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From The Editors Science

What Caused the Halley Bay Colony of Emperor Penguins in Antarctica to Disappear Overnight?

Emperor penguin colonies have thrived in Antarctica since time immemorial, as an abundance of sturdy patches of sea-ice serves as ideal breeding grounds for this tallest and heaviest of all living penguin species.

One such colony was in Halley Bay, on the edge of the Brunt Ice Shelf in the Weddell Sea, where, on an average, some 14,000 to 25,000 breeding pairs flocked every year to breed and raise their fledglings until they were able to fend for themselves.

The colony was the world’s second-largest, representing 5 to 9 percent of the global population of these flightless beauties.

However, thousands of emperor penguin chicks were lost overnight, in 2016, when the sea-ice they were being raised on collapsed under the onslaught of a severe storm.

The hapless hatchlings drowned in the freezing waters of the Weddell Sea, as their feathers were not developed-enough for swimming.

The mass drowning of the little emperors was first spotted and reported by British Antarctic Survey (BAS) scientists, Dr. Peter Fretwell and Dr. Phil Trathan, who noticed the missing Halley Bay colony while studying satellite images.

The species took a massive hit that fateful day, but what’s even more disturbing is that adult emperors have not returned to the breeding site ever since – probably due to the fact that a huge iceberg is predicted to disrupt the site, anyways.

Another reason that has kept the birds away from the spot is the fact that the sea-ice that broke off from the side of the sturdier Brunt shelf never really formed properly to support breeding.

Dr. Fretwell – who is the lead author of the paper entitled, “Emperors on thin ice: three years of breeding failure at Halley Bay,” published in the journal Antarctic Science, said:

“We have been tracking the population of this, and other colonies in the region, for the last decade using very high resolution satellite imagery.
“These images have clearly shown the catastrophic breeding failure at this site over the last three years.

“Our specialized satellite image analysis can detect individuals and penguin huddles, so we can estimate the population based on the known density of the groups to give reliable estimate of colony size.”

Being the tallest and heaviest of all extant penguin species, emperor populations as large as the doomed Halley Bay colony need strong and firm sea-ice under their feet – strong enough to withstand the forces of nature and last until their babies have developed the right feathers for swimming.

The length of time we’re looking at is about nine months, as the birds arrive in April and stay until their offspring fledge in December; that’s how long the sea-ice needs to stay colony-worthy.

If, for some reason, the sea-ice breaks up too soon, then a repeat of what happened in 2016 is a foregone conclusion.

Here’s how Dr. Fretwell explained the situation:

“The sea-ice that’s formed since 2016 hasn’t been as strong. Storm events that occur in October and November will now blow it out early. So there’s been some sort of regime change. Sea-ice that was previously stable and reliable is now just untenable.”

However, all is not lost, as a majority of the breeding pairs that lost their chicks in 2016, have moved to safer breeding sites across the waters of the Weddell, with one colony near the Dawson-Lambton Glacier witnessing a “ more than tenfold increase in penguin numbers,” say the authors.

They have, however, not been able to explain why the sea-ice did not redevelop on the Brunt Shelf’s edge; they have no reason or evidence to attribute this to climate change or to anomalies in atmospheric and oceanic conditions in the Brunt Shelf region.

“It is impossible to say whether the changes in sea-ice conditions at Halley Bay are specifically related to climate change, but such a complete failure to breed successfully is unprecedented at this site,” said Dr. Trathan.

That said, Dr. Trathan believes that global warming will impact the continent’s, and indeed the world’s, emperor penguin populations, in the long run, as strong sea-ice will become increasingly hard to come by in warmer waters.

If computer models of the effects of global warming are anything to go by, we could well be looking at a 50 to 70 percent depletion in the world’s emperor population by the end of this century.

“Even taking into account levels of ecological uncertainty, published models suggest that emperor penguins numbers are set to fall dramatically, losing 50-70 percent of their numbers before the end of this century as sea-ice conditions change as a result of climate change,” Trathan said.

“They’re an important part of the food web; they’re what we call a mesopredator. They’re both prey for animals like leopard seals but they also prey themselves on fish and krill species. So, they do play an important role in the ecosystem,” Dr. Michelle LaRue, an ecologist at the University of Canterbury in New Zealand, told BBC News.

“What’s interesting for me is not that colonies move or that we can have major breeding failures – we know that. It’s that we are talking here about the deep embayment of the Weddell Sea, which is potentially one of the climate change refugia for those cold-adapted species like emperor penguins,” Dr. Trathan said.

“And so if we see major disturbances in these refugia – where we haven’t previously seen changes in 60 years – that’s an important signal,” he added

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From The Editors Science

Getting Started with Solar Energy – A Comprehensive Guide

What is Solar Energy?

Solar energy is radiant heat and light from the Sun. It is an important source of renewable energy. There are two types of these technologies called active solar or passive solar. The difference is how they catch and share solar energy versus how they catch and turn it into solar power.

What is Renewable Energy?

Renewable energy is energy generated from natural resources which are renewable (naturally replenished). The United States currently relies on coal, oil, and natural gas for its energy. Fossil fuels are non-renewable. They draw on finite resources that will dwindle. They are becoming too expensive or too environmentally damaging to retrieve. In contrast, there are many types of renewable energy resources. Solar and wind energy are constantly replenished and will never run out.

Most renewable energy comes either directly or indirectly from the sun. Sunlight is our solar energy. The sun’s heat also drives the winds, captured with wind turbines. Then, the winds and the sun’s heat cause water to evaporate. Hydroelectric power is when this water vapor turns into rain or snow. Then, flows downhill into rivers or streams. Sunlight also causes plants to grow. The organic matter that makes up those plants is known as biomass. Biomass produces electricity, transportation fuels, or chemicals. Bioenergy is the name for using these. Hydrogen is another alternative. Once separated from another element, it is burned as a fuel or converted into electricity. It’s the most abundant element on the Earth. But it doesn’t occur naturally as a gas. Not all renewable energy resources come from the sun. Geothermal energy uses the Earth’s internal heat for a variety of uses. These include electric power production and the heating and cooling of buildings. The energy of the ocean’s tides come from the gravitational pull of the moon and the sun upon the Earth. This is tidal energy. Ocean energy comes from many sources. The ocean waves, from tides and winds. The temperature difference between surface and ocean depths. All these forms of ocean energy can be used to produce electricity.

Why is renewable energy important?

Renewable energy is important because of the benefits it provides. The main benefits are as follows:

Environmental Benefits

Renewable energy technologies are clean sources of energy. They have a much lower environmental impact than conventional energy technologies.

It is energy for our children’s children’s children.

Renewable energy will not run out. Ever. Other sources of energy are finite and will someday be gone.

Jobs and the Economy

Most renewable energy investments spend on materials and workmanship. To build and maintain the facilities, rather than on costly energy imports. Renewable energy investments are usually spent within the United States. Mostly in the same state, and often in the same town. In doing so energy dollars stay home to create jobs. It also fuels local economies, rather than going overseas.

Meanwhile, renewable energy technologies built in the United States are being sold overseas. This also provides a boost to the U.S. trade deficit.

Energy Security

In the early 1970s, the U.S. faced oil supply disruptions. Since then, the U.S. has increased its dependence on foreign oil supplies instead of decreasing it. This increased dependence impacts more than our national energy policy.

What are the types of Solar Energy?

Passive solar is the name for technologies that put buildings facing the Sun. They will find and use special materials that can scatter light. They will also have designs that help the airflow without any blockages.

Active solar uses special systems like solar panels also known as photovoltaic (PV) systems. Also, concentrated solar power (CSP) and solar water heating to save the energy.

What are the most common uses of Solar Energy?

The two most common uses of solar energy are Solar Thermal and Solar Photovoltaic:

  • Solar Thermal systems convert sunlight into thermal energy also known as heat. Most solar thermal systems use solar energy for space heating or to heat water, such as in a solar hot water system. The most common way solar energy is being used today by homeowners in America is by solar hot water systems. The heat from these systems can make steam. By using steam turbines, the steam can generate electricity.

Solar PV systems are systems that can convert sunlight into electricity. These systems use PV cells to do so. The more common term for PV cells is solar cells. Solar cells exist on rooftops,

  • building and even vehicles have them integrated. Power plants have them installed scaled to a megawatt size.

History of Solar Energy

Albert Einstein wrote a paper in 1905 on the photoelectric effect. Titled: “On a Heuristic Viewpoint Concerning the Production and Transformation of Light”. This paper on the photovoltaic effect started to attract scientific attention.

Bell Laboratories worked on silicon semiconductors in the 1950’s. They discovered silicon had photoelectric properties. This helped to develop a silicon cell with 6% efficiency. Early satellites were the primary use for these first solar cells.

The “photovoltaic effect” is the ability of sunlight to excite the flow of electrons (electricity). It was first discovered more than 175 years ago.

Here is a summary of the first 175 years of humans discovery and use of photovoltaic technology:

  • 1839 – Nineteen-year-old French physicist Alexandre Edmond Becquerel observes a physical phenomenon. Discovering light-electricity conversion. While experimenting with metal electrodes and electrolyte.
  • 1883 – American inventor Charles Fritts describes the first solar cells made from selenium wafers.
  • 1888 – First US patent for “solar cell” received by Edward Weston.
  • 1901 – US patent for “method of utilizing, and apparatus for the use of, radiant energy” received by Nikola Tesla.
  • 1905 – Albert Einstein publishes a paper on the theory behind the “photoelectric effect”. The same year he published the “theory of relativity” (E=MC2).

1916 – Robert Millikan experimented Einstein’s theory on the photoelectric effect.

  • 1922 – Albert Einstein wins Nobel Prize for 1905 paper on the photoelectric effect.
  • 1954 – Bell Labs exhibits first high-power silicon PV cell. The same year The New York Times forecasts solar cells will lead to a source of “limitless energy of the sun”.
  • 1963 – Japan installs a 242-watt PV array on a lighthouse, the world’s largest array at that time.  Sharp Corporation produces a viable photovoltaic module of silicon solar cells.
  • 1966 – NASA launches Orbiting Astronomical Observatory with a 1-kilowatt PV array.
  • The 1970s – Research drives PV costs down 80%. Reduced costs of offshore navigation warning lights and horns lighthouses. Also helped railroad crossings and remote use where utility grid connections are too costly.
  • 1976 – Kyocera Corp starts production of Silicon ribbon crystal solar modules.
  • 1977 – US Dept. of Energy establishes US Solar Energy Research Institute in Golden, CO. This organization currently known as NREL, the National Renewable Energy Laboratories.
  • 1990 – Germany launches $500MM “100,000 Solar Roofs” program. The German’s spent the hard money when solar panels were still very expensive.
  • 1994 – Japan starts “70,000 Solar Roofs” PV subsidy program.
  • 2006 – The CA PUC launches the California Solar Initiative (CSI). A $3 billion solar subsidy program spanning 10 years.
  • 2007 – The CSI program starts. Well received by the market, with higher than expected application volume.
  • 2008 – The Energy Policy Act of 2005 (P.L. 109-58) created a 30 percent investment tax credit (ITC). For commercial and residential solar energy systems. Applicable January 1, 2006, through December 31, 2007. Tax Relief and Health Care Act of 2006 (P.L. 109-432) extended credits one more year in December 2006. In 2007, global investment in clean energy topped $100 billion. Solar energy leads clean energy technology for venture capital and private equity investment. The solar tax credits helped to create growth in the U.S. solar industry from 2006-2007. Solar electric capacity installations doubled in 2007 compared to 2006. The Emergency Economic Stabilization Act of 2008 (P.L. 110-343) added an eight-year extension. Covering commercial and residential solar ITC. This eliminated the monetary cap for residential solar electric installations. Companies and utilities paying the alternative minimum tax (AMT) qualified for the credit. In 2009, American Recovery and Reinvestment Act (P.L. 111-5) removed credit cap. The $2,000 credit cap on solar hot water installations no longer existed. This 30% Federal Tax credit renewed until 2016.
  • 2008 – 2012 – Stronger subsidies in Germany and new subsidy programs in Spain, Italy, and Australia. The cost of PV modules falls from approximately $5 per watt to the $1 per watt level.
  • 2010 – 2013 – Chinese manufacturing companies start to build large automated solar cell. Also, solar module production factories. This further reduced the cost of modules down towards $.70 per watt.
  • 2012 – 2015 – Residential solar installations became cost effective for average American households. In 2015, more solar powers installed at home in the US over 18 months than in all the cumulative history before this.
  • May 2015 – The Tesla Motor Company announces product launch of a lithium-ion battery storage. Price point would make it economic for ordinary American householders. Providing ability to store solar power generated during the day for use at night.
  • Dec 2015 – The US Congress passed an 8-year extension to the 30% Federal Income Tax Credit. Ensures the continued growth and adoption of photovoltaic solar power systems in America.

How does Solar Energy work?

Our Sun is a naturally occurring nuclear reactor. It releases tiny packets of energy called photons. These photons travel 93 million miles from the sun to Earth. This only takes about eight-and-a-half minutes. Every hour, enough photons hit our planet to meet global energy needs for an entire year. Yet, solar-generated power in the United States accounts for 0.4% of the total energy consumed. As solar technology is improving, costs are dropping. Our ability to harness the sun’s surplus of energy is on the rise. A report from International Energy Agency states a big change by 2050. Solar energy could become the largest global source of electricity.

In the coming years, everyone will enjoy the benefits. As solar-generated electricity grows more popular every day.

PV solar panels

Photovoltaic (PV) solar panels are made up of many solar cells. Solar cells are made of silicon, like semiconductors. They are constructed with a positive layer and a negative layer, which together create an electric field, just like in a battery. When photons hit a solar cell, they knock electrons loose from their atoms. If conductors are attached to the positive and negative sides of a cell, it forms an electrical circuit. When electrons flow through such a circuit, they generate electricity. Multiple cells make up a solar panel, and multiple panels (modules) can be wired together to form a solar array. The more panels you can deploy, the more energy you can expect to generate.

Basics of electricity

PV solar panels are built of many solar cells. We use silicon to make Solar cells, like semiconductors. They are constructed with a positive layer and a negative layer. Both layers come together to create an electric field, like in a battery. When photons hit a solar cell, they knock electrons loose from their atoms. We can form an electric circuit by attaching a conductor to both positive and negative sides of a cell. When electrons flow through such a circuit, they generate electricity. Many cells make up a solar panel. We create a solar array by wiring many panels (modules) together. The more panels you can deploy, the more energy you can expect to generate.

Alternating current is one form of electricity, also known as AC. This is when electrons are pushed and pulled, reversing direction. This exchange is much like the cylinder of a car’s engine. Generators create AC electricity when a coil of wire is spun next to a magnet. Many different energy sources can “turn the handle” of this generator. Examples include gas or diesel fuel, hydroelectricity, nuclear, coal, wind, or solar.

The U.S. electrical power grid chose AC electricity. It is less expensive to transmit over long distances. Yet, solar panels create DC electricity. The only way to get DC electricity into the AC grid is by using an inverter.

Inverters

A solar inverter takes the DC electricity from the solar array. It then uses that to create AC electricity. Inverters are like the brains of the system. Not only do they invert DC to AC power. They also provide ground fault protection. Provide system stats including voltage and current on AC and DC circuits. As well as stats on energy production, and largest power point tracking.

Central inverters have dominated the solar industry since the beginning. One of the biggest technology shifts in the PV industry was the introduction of micro-inverters. These inverters optimize for each individual solar panel. Rather than an entire solar system, as central inverters do. This enables every solar panel to perform at maximum potential. One solar panel will not drag down the performance of the entire solar array. In contrast, central inverters optimize for the weakest link.

Putting it all together

Here is an example of how a residential solar energy installation works. First, sunlight hits the solar panel or PV array on the roof. The panels convert the energy to DC current. This flows to the inverter. The inverter changes the solar DC power in 240V AC. This is suitable for your household appliances and feeding into the grid. Your home uses electricity from the solar PV modules first. Any additional demand is supplied from the Grid. A meter measures your electricity production and consumption. Any excess is exported to the electricity Grid.

The above example illustrates the basic idea of solar energy in the home. At this point, there may be a few questions. What happens if you are not at home to use the electricity the solar panels generate every sunny day? What happens at night when the solar system is not generating power in real time?

One way to solve this is to store the solar-generated energy for later use. If there is no home battery installed, the energy will flow back into the grid. But don’t worry, you still benefit from a system called “net metering”. This is the other solution.

Net metering

A grid-tied PV system has no batteries. Neighbors will receive any excess power generated that is not used. This is known as “back feeding” the grid. At night, the grid will provide energy for lights and other appliances as usual. This covers solar users in exchange for the excess energy they shared with the grid during the day. A net meter records the energy sent compared to the energy received from the grid.

Now over 20,000 megawatts of solar electric capacity is operating in the United States. Around 650,000 homes and businesses have now gone solar.

In 2014, every two-and-a-half minutes a new solar project was installed. Projections say solar capacity will double in the next two years. Solar energy is the wave of the future. The sun belongs to everyone. Anyone can enjoy the freedom solar power systems provides. We need to commit to unlocking its vast energy.  It all starts with a single solar cell.

How much energy can you get from solar electricity?

The map above shows the average amount of solar power produced each day from each state of the USA. Each number corresponds to the amount of kWh produced by the 1-kilowatt solar power system. As you can see the amount of electricity varies depending on your location. It also varies by the season and so the estimates given in the map above are annual averages.

Please note that these numbers are averages for the whole state. Some parts of some states have different climatic conditions. These numbers may not reflect when you live necessarily.

Across the USA daily production per kilowatt installed varies. From as little as 2.9 kWh per kW per day to almost to 4.7 kWh in very sunny locations.

The amount of electricity produced by each kW of solar you install will vary. This will depend on the level of solar irradiation that falls on your home or business. Solar irradiation is often measured in Sun Hours. Meteorologists measure Sun Hours in megajoules. Measuring total amount of irradiation in an area in each day. Next, they calculate complete hours compared to an area with 1000 megajoules per square meter on an area.

For example, if there were 500 megajoules falling on average over a 12 hour day then the Sun Hours would be 6.

These numbers may be confusing but are important. They relate to the output of solar panels. Solar panels are rated based on the power they produce. Per 1000 megajoules per square meter of irradiation falling on them.

Sun Hours measure irradiation. With this number, we can work out the actual amount of power we will produce. Real world solar power systems do produce less than their rated output.

The factors that reduce power rating include:

  • Inverter inefficiency – most inverters will lose 3-5% of electricity when converting from DC to AC
  • Cable Losses – small amounts of power lost through resistance in the cables
  • Dirt – dirt, and grime on solar panels will reduce their real world performance.
  • Temperature losses – solar panels are rated based on what they produce at 25 degrees celsius. As the cells in solar panels get hotter there is more resistance to the flow of electrons across the cells. Their power output reduces compared to when they are at a lower temperature. Even with the same level of irradiation.

Overall, total losses due to these derating factors will generally be between 20-30%. Yet, when we are working out the real world power of a system we usually use a derating factor of around 25%.

Please note when using the map above, estimates assume a perfect installation. Positioned due south, at an optimal tilt angle, and unshaded.

Pros and Cons for Solar Energy

Below are the advantages and disadvantages of installing solar panels on your home.

Advantages of Solar Energy

Marginal cost of generation is zero

Once the capital cost of installing a solar power system has returned, the energy is free. This is the most significant attraction for American homeowners. The only remaining question is how long the payback period will last. When comparing, it is possible this is a better deal than other ways to invest money.

Most homeowners are more interested in financial aspects of installing this system. Rather than the environmental benefits.

Insurance against rising power prices

Current solar panels have a year life of at least 25 years. By installing a solar power system on you home, you lock in a price for energy during this period. First, you need to calculate how much energy the solar panels will produce. Next, you can get an accurate price quote calculating each kilowatt-hour over the next 25 years. Many consumers are now able to get a Levelized cost of energy of $0.10 per kilowatt-hour. Next work out your average amount to pay for power over the next 25 years. Once your quote is available, you can compare the savings.

The average consumer with a $150 per month power bill can see savings in the range of $30,000 over the life of a solar system. At the beginning, the monthly savings are not huge. This may only be $50 per month but in the 25th year, it can reach savings of up to $300 per month.

Renewable

Solar energy is a renewable energy source. NASA estimates that the sun will shine for another 6.5 billion years. This means that solar energy is abundant, and will never run out in our lifetime. The surface of the earth receives 120,000 terawatts of solar radiation (sunlight). This is 20,000 times more power than what needed to supply the entire world.

Environmentally Friendly

Harnessing solar energy does not generally cause pollution. There are some emissions during production and installation of solar energy equipment. These emissions are minimal when compared to generating electricity from fossil fuels. An Australian government research body (The CSIRO) estimates energy payback is 1.5 years. This means it takes a solar panel 1.5 years to generate the amount of power it took to make it. These numbers are from a statistic back in 2009. It is likely a lot quicker payback now. As solar panels last 25 years, this is good news.

Geographically widely available

The level of solar irradiation that falls upon the earth varies with the geography of the planet. Generally, the closer to the equator the more accessible solar energy is. What most do not realize is that solar energy is available anywhere.

In the sunniest parts of America, a solar system will produce on average 4.7 kWh of power per 1 kilowatt of solar panels.

The least sunny areas are different, such as in the mountains and northeast. In this area, it will produce 2.9-kilowatt hours per kilowatt, per day. Some areas are better than others are. For solar power, it is still viable in almost all locations.

Reduces Electricity Costs

Two schemes have been recently introduced net metering and feed-in tariff (FIT) schemes. Homeowners can now “sell” excess electricity or receive bill credits. This is possible during times a home produces more electricity than consumed. This means that homeowners can reduce their electricity expenses by going solar.

Data from www.solar-estimate.org show that adding solar panels can bring big savings. Annual savings of well above $1000 per year in many states. 

In California, residents save on average $28,000 after 20 years! The availability of solar finance options has made it more affordable and available. Through Solar PPA agreements and zero down loans.

Community Solar can be used to overcome installation issues

Many American homes are unfit for solar panels. Due to shading, insufficient space and ownership issues.

With the introduction of shared solar, homeowners can subscribe to “community solar gardens”.  With this approach, your own rooftop does not need any solar panels. the community generates the solar electricity.

Installation costs of many panels installed on vacant land are cheaper. This is a great advantage.

With this approach, Legislation is a need. This enables installations of community solar in each state. This has been available for some time now, but only started to arrive in California and New York.

No moving Parts means no noise and little maintenance

Solar panel systems have no moving parts. Also, there is no noise from the PV technology. When compared to other renewable technologies, solar wins in this category. One alternative like wind turbines has moving parts and causes noise pollution.

Financial Support from Government/State

In December 2015, the US Senate passed an extension of the 30% Renewable Tax Credit. This federal incentive extended the tax credit for a further 8 year.

There are also rebates available in some jurisdictions. Available at either the state, county or utility company level.

Technology is improving

Technology is always developing new advancements. This includes the design and manufacture of solar power equipment. Solar cells are becoming more efficient at turning solar energy into electricity. The amount of space required to generate a specific amount of solar power is reducing. As the popularity of solar increases, so will the dramatic advances. Improvements are incremental. Nothing revolutionary yet, but the future is bright.

Disadvantages of Solar Energy

High Capital Cost

Most people understand that solar power is expensive. This is one of the most debatable topics on the entire solar energy pros and cons list. Politics is the driving forces behind the development of solar energy.

Solar power received government subsidies. Yet, oil and coal industries have also been subsidized.

In 2010, coal received $1,189 billion in federal subsidies. Coal also received support for electricity production. Meanwhile, solar is not far behind at $968 billion.

Nowadays, the best solar panels can be cheaper than buying electricity.

Solar energy is an intermittent energy source

There are three aspects to the intermittent nature of solar power:

  • The sun does not shine at night meaning solar panels do not generate power at night.
  • The sun shines with different intensity. This changes based on location and time of year. Also, each day the sun shines at different times.
  • Cloud cover can have a significant effect on the amount of energy produced by solar panels.

In the past, all these factors have meant that solar power is unreliable. It is a risk if relied on for baseload or for mission critical applications.

This is now changing. Tesla Motors announced last year a new product to solve this issue. A Lithium Ion battery for the home. This solution will allow consumers to cost-effectively store solar power energy.

Energy Storage is Expensive

Energy storage systems such as batteries will help smoothen out demand and load. This will make solar power more stable, but these technologies are currently expensive.

Looking at the numbers, we are fortunate. There is a good relation between our access to solar and energy demand. Our electricity peaks in the middle of the day. That is the same time there is a lot of sunlight!

Associated with Pollution

While solar power is less polluting than fossil fuels, some problems do exist. There are some greenhouse gas emissions associated with some manufacturing processes. Nitrogen trifluoride and sulfur hexafluoride are the talked about ones. The production of solar panels has found traces of these.

These are some of the most potent greenhouse gasses. Having many, thousand times the impact on global warming compared to carbon dioxide. Transportation and installation of solar power systems can also cause pollution.

The lesson of the day is: There is nothing that is completely risk-free in the energy world. Yet, solar power is most favorable when compared with all other technologies.

Exotic Materials

Certain solar cells need materials that are expensive and rare in nature. This is especially true for thin-film solar cells. Based on either cadmium telluride (CdTe) or copper indium gallium selenide (CIGS).

Requires Space

Power density is also called watt per square meter (W/m2). Used when looking at how much power an energy source has in a certain area. In this case, we are looking at real estate. Low power density means we need more real estate to get the power we demand at a good price. The global mean power density for solar radiation is 170 W/m². This is more than any other renewable energy source. But it cannot compare to oil, gas and nuclear power. Not yet anyway.

Solar doesn’t move house

One disadvantage with installing solar panels on your home is that it is expensive to move. If you move house, it is not easy to bring it with you. The net metering agreement with your utility is fixed to the property.

Yet, in practice, solar panels add value to a home. If you do move, you are likely to see the value of your investment in solar panels reflected in a higher sale price. The easiest way, in this case, is to buy the solar panels outright. With a lease or PPA, you need the new owner to agree to take over the agreement. That can be tricky.

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From The Editors Science

Images of Giant Spinning Ice Disk in a Maine River Awes People Across the Globe

A huge spinning ice disk that suddenly appeared on the surface of the Presumpscot River in the city of Westbrook, Maine, this week, has generated a lot of interest on social media.

People are having a field day with their own explanations of this gigantic version of a rare natural phenomenon, with comparisons being drawn with crop circles and the surface of the moon, while some have even gone to the extent of calling it the handiwork of aliens.

“Cool! Looks like a moon,” said a certain Candice Dutil.

“Wessie,” wrote Matt Ireland.

“Frozen Crop Circle,” posted David Lawrence.

While sightings of rotating ice disks on water bodies dates as far back as the late nineteenth century, none has been as huge as the one the people of Westbrook have been treated to this week.

The intriguing circle of ice, which measures some 90 meters (300 feet) in diameter, was spinning counter-clockwise at the speed of what locals described as a “brisk walk.”

The disk has apparently stopped spinning and has moved to the other side of the river.

According to Kenneth G. Libbrecht, an ice physics expert and a professor at the California Institute of Technology in Pasadena, Calif., ice disks are generally twenty to thirty feet across, which effectively makes the Presumpscot River disk 10-15 times larger – a record, indeed.

“It might be a world-record size if anybody were keeping track,” Libbrecht told The New York Times.

Rob Mitchell, a local entrepreneur with business interests at the Presumpscot riverfront alerted Westbrook city’s marketing and communications manager Tina Radel about the somewhat eerie- looking formation on Monday.

“There were ducks sitting on it,” Mitchell said.

“The ducks were rotating on this big Lazy Susan. It was a big duck-go-round,” he added.

The incredible drone footage that Radel released later has gone viral on the internet, generating “an overwhelming reaction,” according to Radel.

“People are loving it,” she said.

According to the Portland Press Herald, the spinning sheet of ice has created almost as much buzz in Westbrook as the spotting of a giant snake devouring a beaver in the same area had done in 2016.

While there are no footages of the snake, which was dubbed “Wessie” by the locals, the rotating sheet of ice is a stark reality and the images and videos will always be there for all to see and marvel at, long after the ice has melted into the waters of Presumpscot.

Watch the drone footage here.

It kind of looks like a crop circle,” Doug Bertlesman, a web developer at Ethos Marketing, was quoted by the newspaper as saying.

“It’s pretty wild to look at,” he said, adding: “It’s certainly not every day that you can watch a spinning circle of ice in the river.”

While the disk was certainly rotating, it appeared to be doing so at a fixed spot, without going upstream or downstream at the time.

“It’s stuck right there. It’s not going anywhere,” Mitchell said. “I think it will continue to gain in thickness as long as it keeps spinning.”

However, as mentioned, the disk has shifted to the opposite bank of the river and appears to have stopped rotating.

The initial explanation for these ice disks was that swirling eddies caused circles of ice to form and rotate on rivers.

“Since the water in the eddy is flowing more slowly than the main current, it’s more likely to freeze, creating the icy disc,” The Boston Globe quoted John Huth – an experimental physicist at Harvard University, as saying

“The icy disc retains the rotation of the eddy, as it’s caught in it,” he explained.

However, this explanation is not entirely correct because if eddies were the sole cause for these spinning mysteries then smaller disks would spin faster than larger ones, but the fact is that these circles of ice are known to rotate at roughly the same speed regardless of their size.

Also, if eddies were the reason, ice disks would not have spun on still water which they are also known to do.

Subsequent experiments, however, suggested that the water melting off the disks sank straight down because of being colder and, hence, denser than the surrounding waters of the river.

Just like the water in your kitchen sink spins before draining out, the sinking cold water from the melting disk also swirls like an eddy as it goes down, causing the ice to spin on the surface.

https://twitter.com/daisandconfused/status/1085022237986615296

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From The Editors Science

China’s Chang’e-4 Mission Witnesses the First Seeds Germinate on Moon

Update: The lunar cottonseed sprouts died after mission scientists were forced to cut the power supply to the batteries that kept them alive.

The news came two days after it was announced that cottonseeds had sprouted on the moon.

The extreme conditions on the inhospitable far side of the moon also caused other seeds, yeast and fruit fly eggs to die too.

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China’s Chang’e-4 mission has literally sown the first seeds for future lunar living by managing to sprout cotton seeds it carried with it to the far side of the moon.

Images beamed back by Chang’e-4 and released by the Advanced Technology Research Institute at Chongqing University clearly show small green shoots that have sprouted through a grid-like structure inside a canister in which the experimental cotton seeds are housed.

Although the probe has also carried with it seeds for potato, rockcress, and rape plant, these were the only seeds that have sprouted so far; it remains to be seen when, or if, the others follow suit.

The lunar lander has also carried with it some experimental silkworm eggs, fruit fly pupae, and yeast.

While similar experiments have been successfully carried out on the International Space Station, this is the first time seed of any kind has sprouted on the moon, which is being seen as a significant step towards sustaining extended space missions where the ability to grow plants will come in super handy.

“This is the first time humans have done biological growth experiments on the lunar surface,” said Xie Gengxin, who led the design of the experiment, on Tuesday (Jan 15).

Earlier this year, in a never-before-attempted mission, the China National Space Administration (CNSA) soft-landed a robotic probe, the Chang’e-4, in a crater within a crater on the far side of the moon.

The spacecraft made a picture-perfect touch down in the Von Karman Crater – a huge southern hemisphere impact crater, measuring about 112 miles (180 kilometers) in diameter, located within an even bigger impact crater – the 1,600-mile (2,500-kilometer) South Pole-Aitken Basin.

Although Chang’e-4 had made it to the Moon’s orbit four days after launch, it began its final descent about three weeks later from an elliptical landing orbit almost 10 miles above the lunar surface.

When it was 100 meters above the landing site, the spacecraft briefly paused in its vertical approach, hovering over the landing zone to survey the topography below and selecting a relatively flat spot before resuming its descent.

The impeccable touchdown was appreciated by NASA Administrator Jim Bridenstine, who congratulated the mission team on “a successful landing on the far side of the Moon,” calling it “a first for humanity and an impressive accomplishment.”

The final approach phases were achieved autonomously by the spacecraft, as remote intervention from mission control in China was not possible during this stage of the mission.

“This is a great technological accomplishment as it was out of sight of Earth, so signals are relayed back by their orbiter, and most of the landing was actually done autonomously in difficult terrain,” Prof. Andrew Coates of UCL Mullard Space Science Laboratory (MSSL) in Surrey, England, was quoted by The Guardian as saying.

“The landing was almost vertical because of the surrounding hills,” Prof. Coates added.

Soon after landing, Chang’e-4 deployed its lunar rover named “Yutu-2” – Chinese for “Jade Rabbit-2” – which sent back the first ever close-up shot of the mysterious far side of our only known natural satellite.

The Chinese space agency also shared an image of Yutu-2’s deployment, along with pre- and post-landing images, all of which were relayed through the Queqiao (Magpie Bridge) satellite orbiting at the Earth-moon Lagrange point 2 beyond the far side.

Queqiao was, in fact, launched in May last year for the exact same purpose because direct communication with the far side of the Moon is impossible, what with the Moon’s entire mass blocking the exchange of direct signals to and from Earth.

While humans have glimpsed, and even mapped, the lunar far side in the past – thanks to NASA’s Apollo 8 mission half a century ago and the Soviet Luna 3 mission a decade prior to that – no spacecraft had ever touched down on the untrodden ground, until Chang’e-4 changed all of that.

In the past decade. or so, China has made rapid advances in space technology and is the only country in the world to have soft-landed a space vehicle on the Moon since the then Soviet Union’s 1976 Luna 24 mission to retrieve samples Moon soil.

China achieved the feat in December 2013, landing its Chang’e-3 rover on Mare Imbrium –  a vast lava plain within the Imbrium Basin on the near side of the Moon, becoming only the third country after Russia and the United States to achieve a lunar touchdown.

Encouraged by Chang’e-3’s success, China stepped up its lunar program for an even bigger mission, the first phase of which came to a successful conclusion with Chang’e-4’s Thursday landing on the targeted far side.

Comprising of a lander and a small rover, Chang’e-4 was, in fact, a backup spacecraft manufactured with the Chang’e-3.

It was only in 2015 that China announced its plans of using the spare space vehicle to launch something so complex that it had never been attempted before.

The nearly four-metric-ton Chang’e-4 has carried with it eight scientific instruments – four each on the lander and the rover.

The lander is equipped with the Landing Camera (LCAM), the Terrain Camera (TCAM), the Low-Frequency Spectrometer (LFS), and the Lunar Lander Neutrons and Dosimetry (LND).

And, the rover is carrying the Panoramic Camera (PCAM), the Lunar Penetrating Radar (LPR), the Visible and Near-Infrared Imaging Spectrometer (VNIS), and the Advanced Small Analyzer for Neutrals (ASAN).

As mentioned, Chang’e-4 also carried with it a small experimental payload of silkworm eggs, fruit fly pupae and yeast, in addition to seeds for potato, rockcress, rape plant, and cotton to check how they develop in the inhospitable lunar environment.

The huge amounts of scientific data and information that the spacecraft’s state-of-the-art instruments are capable of garnering will go a long way in helping researchers understand why the far side of our Moon is so vastly different from the side we’re familiar with.

For example, the lunar terrain on the tidally-locked near side is largely dark basaltic plains called the lunar maria, while the far side is mountainous and rugged and, hence, difficult to land anything on.

Since the Moon takes the same amount of time (28 days) to orbit our planet as it does to rotate once on its axis, we always get to see the same side of the natural satellite, with the opposite side forever hidden from view.

“Since the far side of the moon is shielded from electromagnetic interference from the Earth, it’s an ideal place to research the space environment and solar bursts, and the probe can ‘listen’ to the deeper reaches of the cosmos,” CNSA’s deputy director for the Lunar Exploration and Space Program Center, Tongjie Liu, was quoted by CNN as saying.

China’s next lunar run will be the Chang’e-5 sample-retrieval mission, which CNSA started preparing for in October 2014 when it launched the Chang’e-5T1 mission to run atmospheric re-entry tests on the -4Chang’e-5 capsule.

“Experts are still discussing and verifying the feasibility of subsequent projects, but it’s confirmed that there will be another three missions after Chang’e 5,” said Wu Yanhua, deputy head of the China National Space Administration (CNSA), at a press conference.

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From The Editors Science

Scientists Detect Thirteen Fast Radio Bursts (FRBs) from 1.5 Light Years Away

Using the Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB radio telescope at the Dominion Radio Astrophysical

Observatory in British Columbia, scientists have detected thirteen fast radio bursts, or FRBs, including one that repeated as many as six times.
Fast Radio Bursts, or FRBs, which are basically highly dispersed radio signals from outside the Milky Way that last for a few milliseconds, have been baffling scientists for years, now.

What’s different about these thirteen FRBs, though, is the fact that they are brighter and have the lowest radio frequency compared to previous detections, which the researchers think has something to do with their source of origin roughly 1.5 billion lightyears away.

“It doesn’t mean that they’re traveling from further away,” study author Shriharsh Tendulkar, a postdoctoral fellow in the department of physics at McGill University, was quoted by National Geographic as saying.

“As light propagates through the hot gas and plasma in the intergalactic medium and the interstellar medium, it has a bunch of different effects on the signal,” Tendulkar said.

The fact that at least seven of the thirteen blasts detected by the CHIME/FRB instrument were as low as 400 MHz points towards the possibility of even lower frequency signals out there – too low for CHIME to pick up.

“[We now know] the sources can produce low-frequency radio waves and those low-frequency waves can escape their environment, and are not too scattered to be detected by the time they reach the Earth,” explained Tom Landecker, a CHIME team member from the National Research Council of Canada.

“That tells us something about the environments and the sources,” he said, adding: “We haven’t solved the problem, but it’s several more pieces in the puzzle.”

“Whatever the source of these radio waves is, it’s interesting to see how wide a range of frequencies it can produce,” said Arun Naidu, another CHIME team member from McGill University.

“There are some models where intrinsically the source can’t produce anything below a certain frequency,” Naidu added.

While this astrophysical phenomenon is not an uncommon occurrence, repeating series of FRBs definitely is, as this is only the second instance in sixteen years that scientists have detected a “repeater.”

FRBs never seemed to repeat themselves until FRB 121102 was first discovered on November 2, 2012, at precisely 06:35:53.244 (Date and Time [UTC] for 1581.804688 MHz) by the Peurto Rico-Arecibo Observatory radio telescope.

In 2015, Shami Chatterjee, a senior researcher at the Cornell Center for Astrophysics and Planetary Science and an international team of astronomers were able to accurately pinpoint the source of FRB 121102, which they said was a dwarf galaxy some 3 billion lightyears away from Earth – twice the distance of the latest repeater – FRB 180814.

By the way, fast radio bursts are named according to the date the signal is first detected – in the YYMMDD format prefixed by the letters FRB; which means FRB 180814 was detected on Aug 14, 2018, and the first repeater FRB 121102 was picked up on Nov 2, 2012.

“The host galaxy for this FRB appears to be a very humble and unassuming dwarf galaxy, which is less than 1 percent of the mass of our Milky Way galaxy,” Tendulkar said in a statement at the time.

“That’s surprising. One would generally expect most FRBs to come from large galaxies which have the largest numbers of stars and neutron stars — remnants of massive stars,” he added.

Although the origins of the two repeaters are 1.5 billion light years apart, there are striking structural similarities between them, notes Tendulkar.

“The fact that we see these multiple structures in the burst was very similar to the first repeating fast radio burst. This is very uncommon,” he said.

“Now there is this tantalizing evidence that these bursts’ structures are seen only in repeaters,” he concluded.

This basically means that FRBs sharing the same structure are possibly repeaters even if they don’t repeat when detected.

Determined to find more conclusive evidence, the researchers are continuing their hunt for more FRBs, keeping the CHIME/FRB instrument trained on the region of the sky where the high-speed radio bursts came from, in addition to following up on already detected FRBs with other radio telescopes.

“We are trying to build up clues and trying to understand whether the repeating fast radio bursts and single fast radio bursts are different populations,” Tendulkar said.

“Do they come from different objects? Or are they related in some way to each other? We are trying to figure these things out, so that’s really exciting,” he added.

“The CHIME discovery points to a huge potential,” said Chatterjee.

“I’m intensely curious how many [fast radio bursts] they are sitting on now. They must have dozens or hundreds,” he added.

Another pertinent question that Tendulkar and the CHIME team would probably be trying to find an answer to would be:

What cosmic event creates these millisecond-duration bursts of radio signals that reach Earth from distances of 1.5 and 3 billion lightyears and has the capacity of generating more energy than 500 million Suns?

“There is a lot of fun in the not knowing,” says Tendulkar.

“You keep adding more information, but as in all sciences, whenever you solve one mystery, it always opens up three more.”

So, are we talking about aliens here?

Unlikely, but you never know!

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From The Editors Science

Citizen Scientists Find “Super Earth” in Habitable Zone of Binary Star System 226 Lightyears Away

Two NASA interns and a team of amateur astronomers have discovered a new exoplanet roughly twice the size of Earth while gleaning through data captured by the U.S. space agency’s now-defunct Kepler space telescope.

Although the so-called “Super Earth” was first spotted by the “citizen scientists,” using information gathered by the Kepler space telescope during Campaign 4 of its extended K2 “Second Light” mission back in 2015, the data was discarded as unreliable due to issues with two of Kepler’s reaction wheels.

The same team analyzed the Campaign 4 data a second time and uploaded the re-processed information on Exoplanet Explorers – a new Zooniverse project open to public searches of Kepler’s K2 observations to locate new transiting planets – in 2017.

To cut a long story short, mistakes were made but follow-up observations, using data from the Keck Observatory in Hawaii, NASA’s Infrared Telescope – also in Hawaii, the agency’s Spitzer Space Telescope, and European Space Agency’s (ESA’s) Gaia space observatory, allowed the team to confirm the existence of K2-288Bb at the 233rd American Astronomical Society meeting in Seattle on January 7, 2019.

“It’s a very exciting discovery due to how it was found, its temperate orbit and because planets of this size seem to be relatively uncommon,” said Adina Feinstein, a graduate student at the University of Chicago, Illinois, and the lead author of the study paper due to be published in The Astronomical Journal.

“It took the keen eyes of citizen scientists to make this extremely valuable find and point us to it,” Feinstein said.

Officially known as K2-288Bb, the exoplanet is possibly a rocky, or a gas-rich planet along the lines of Neptune.

It is located in the habitable zone, also known as “Goldilocks’ zone,” of a binary star system of the same name minus the suffix “b” in the constellation Taurus some 226 lightyears away from Earth.

The binary stellar system K2-288B, which K2-288Bb is a part of, contains two dim stars about 5.1 billion miles (8.2 billion kilometers) apart.

The larger and brighter of the two stars is about half the mass and size of our own Sun, while its stellar companion is about one-third of our Sun’s mass and girth.

However, it’s the lesser of the two stars that K2-288Bb orbits once every 31.3 Earth-days.

Exoplanets

Simply put, an exoplanet is a planet that does not orbit our Sun but belongs to a different planetary system and orbits the star (sun) of that particular system.

They are also referred to as extrasolar planets; aptly so because they’re not part of our Solar System.

An exoplanet is named after the star of the system to which it belongs with a lower case letter added to the name as a suffix.

The first exoplanet discovered in the system gets the suffix ‘b’, with subsequent discoveries getting the letters c, d, e, and so forth, in the order they are found.

That is why the new exoplanet is named K2-288Bb – the ‘b’ at the end being the suffix for the first planet discovered in the stellar system K2-288B.

To give another example, TRAPPIST-1, an ultra-cool dwarf star in the constellation Aquarius, 39 light-years away from the Earth, has ten known exoplanets

Hence, based on the aforementioned naming methodology, the seven latest discoveries, starting from the planet closest to the star, are named TRAPPIST-1b, TRAPPIST-1c, TRAPPIST-1d, TRAPPIST-1e, TRAPPIST-1f, TRAPPIST-1g, and TRAPPIST-1h.

The letter ‘a’ by default goes to the parent star, though not shown with the name.

Habitable Zone (Goldilocks’ Zone)

An planet or exoplanet is said to be in the habitable zone of a planetary system when it is orbiting at an ideal distance from the system’s star/sun to potentially support life of any kind – not too close to the star to be too hot to support water formation, neither too far for water to be in a permanent freeze.

Kepler Space Observatory

Named after the astronomer, Johannes Kepler, the Kepler space observatory had been in an “Earth-trailing heliocentric orbit” ever since its launch in March 2009 as part of NASA’s program to discover Earth-sized exoplanets.

After nine years of service to science and space research, Kepler was decommissioned by the space agency on October 30, 2018.

The spacecraft was designed to scan an area of the galaxy in the vicinity of our own solar system to identify Earth-like exoplanets in and around the ‘habitable zones’ of their planetary systems.

Equipped with a photometer that continuously monitored the brightness of over 145,000 main sequence stars in a fixed field of view, Kepler beamed the collected data back to Earth for analysis.

The method involved detecting the periodic dimming which happens when exoplanets cross in front of their host star – similar to the Eclipse concept.

Due to noise interference in the data from the stars as well as the spacecraft, the mission was supposed to be extended till 2016 in order to achieve all mission targets.

However, built to endure the harsh space conditions for a maximum of 3.5 years, Kepler ran into trouble on July 14, 2012, when one of the four reaction wheels of the craft stopped turning.

Incident-free functioning of the three remaining reaction wheels was now critical to the completion of the mission but fate would have it differently.

On May 11, 2013, the continuation of the mission was seriously jeopardized when a second reaction wheel stopped working.

NASA failed in its attempt to fix the two out-of-commission reaction wheels, publicly throwing in the towel on August 15, 2013, with an announcement to the effect.

The agency then appealed to the space science community for alternative plans for continuing the search for exoplanets using the two working reaction wheels and thrusters.

The K2 “Second Light” proposal, which involved using the limited capabilities of the handicapped Kepler to track habitable planets around smaller and dimmer red dwarfs, was made in Nov 2013, getting NASA’s official nod in May 2014.

Since then until its demise, the space telescope’s had surveyed and cataloged hundreds of new planetary candidates.

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From The Editors Science

NASA to Crash 13,500mph Spacecraft into an Asteroid Moon in Experimental Earth-Saving Mission

With some 20,000 near-Earth asteroids and comets orbiting the Sun, NASA and other space agencies have been constantly tracking these near-Earth objects (NEOs) since the 1990s in a joint initiative called ‘Spaceguard.”

However, merely chasing these potential threats is not going to save Earth from another mass extinction and, probably, thousands of years of ice age, should one of them slam into us.

The good news is that NASA has been working on a planetary-defense mission called DART, an acronym for Double Asteroid Redirection Test, to save us from exactly such an eventuality.

DART is essentially an impactor spacecraft that NASA plans to crash into an asteroid satellite at 13,500 miles per hour in an effort to change its course.

The idea is to find out how much the car-sized impactor can change the trajectory of the flying space rock and whether it’s enough to redirect an Earth-bound asteroid safely away from us.

The space rock that NASA has in its crosshairs for the planned Oct 2022 smash-up is, in fact, a satellite moonlet nicknamed Didymoon, about seven million miles away from Earth.

The moonlet, which is about 150 meters across, orbits an 800-meter-wide asteroid called Didymos, from where it gets its nickname.

While Didymoon is not on a collision course with Earth and poses no threat to us whatsoever, a detailed study of the space object and then slamming into it to bump it off its bearings should provide the DART team with useful data that can come in handy in averting a real asteroid threat if ever it comes to that.

Speaking to Space.com at the annual meeting of the American Geophysical Union, Nancy Chabot – a planetary scientist at Johns Hopkins University’s Applied Physics Laboratory and project scientist for DART – said that “science-driven” space missions were largely focused on understanding the origins of our solar system and its building blocks, but planetary defense was all “about the present solar system and what are we going to do in the present.”

Chabot says that tracking the moonlet and knowing its exact location, instead of having a ballpark idea of its whereabouts, is going to be crucial to the mission because the DART team wants to hit it head-on for maximum impact.

“It’s interesting because it’s a space mission, but the telescopes are such a huge, important part of the mission succeeding,” Chabot told space news website.

“We have to know where this moon is in order to impact it, to make this maximum deflection,” she said.

“We kind of take for granted that we know where everything is at all times,” she continued

“We understand where the system is as a whole, but specifically where that moon’s gonna be [requires tracking] because we want to try to hit it head-on,” Chabot added.

However, at least ten to twenty years’ advance warning will be needed to pull off something like redirecting a huge asteroid in a real-threat scenario, according to Chabot.

She says that “the idea of a kinetic impactor is definitely not like [the movie] ‘Armageddon,’ where you go up at the last hour and you know, save the Earth.”

She adds: “This is something that you would do five, 10, 15, 20 years in advance — gently nudge the asteroid so it just sails merrily on its way and doesn’t impact the Earth.”

The 14 radar images below, captured by the Arecibo Observatory radio telescope in Puerto Rico in November 2003, show Didymos (65803) and its moonlet.

 (Credit: NASA)

If all goes according to plan, the mission will launch as early as June 2021, with an expected collision date in Oct 2022, as mentioned earlier.

While ground telescopes will track the new course of the twin objects post-impact, an Italian Space Agency CubeSat called Light Italian CubeSat for Imaging of Asteroids will accompany DART on its mission to keep an eye on proceedings.

Additionally, as part of an international Asteroid Impact Deflection Assessment (AIDA) mission, the European Space Agency (ESA) will launch two CubeSats, APEX (Asteroid Prospection Explorer) and Juventas, onboard the agency’s Hera spacecraft, in time to reach the binary asteroid system sometime in 2026 to record the effects of the DART collision, according to NASA.

“To test potential techniques in “deflecting” an asteroid – one of the preferred methods for mitigating a threat – DART will travel to the Didymos binary asteroid system via its a xenon-based electric propulsion system, steering with an onboard camera and sophisticated autonomous navigation software,” says the U.S. space agency.

DART is expected to send back a close-up shot of the Didymoon surface – its last transmission to Earth – before it is pulverized into space dust.

For any Solar System body to qualify as a near-Earth object, its closest approach to the Sun has to be less than 1.3 astronomical units (AU), the equivalent of nearly 121 million miles.

Among the 20,000 near-Earth asteroids and comets orbiting the Sun is a 500-meter-wide asteroid called Bennu, which has a 1-in-2,700 chance of smashing into Earth sometime between 2175 and 2196, say scientists.

The potentially hazardous object (PHO), “listed on the Sentry Risk Table with the second-highest cumulative rating on the Palermo Technical Impact Hazard Scale,” is currently 54 million miles from Earth.

The Sun-orbiting asteroid has been in NASA’s crosshairs ever since its discovery by the Lincoln Near-Earth Asteroid Research (LINEAR) project in 1999.

So focussed has the space agency been on Bennu that in 2016 it sent its ORISIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) spacecraft to the asteroid on a sample-return mission.

After traveling through space for more than two years, the spacecraft finally reached the proximity of Bennu last month.

Over the coming months, the NASA spaceship will map the asteroid to identify the best possible sample-collection site before making a slow descent to the surface to collect samples using its robotic arm.

OSIRIS-REx will begin its return journey after it has safely tucked away its precious cargo of Bennu samples inside a Sample-Return Capsule (SRC).

The SRC is expected to re-enter Earth’s atmosphere and land at the U.S.

Air Force Utah Test and Training Range on Sep 24, 2023 – about a year after DART smashes into Didymoon, hopefully, achieving the desired results.

For all we know, Bennu might just turn out be the asteroid that NASA has to knock off-course to save the planet in the future; that’s when the knowledge gained from the DART mission will come in handy – unless the 500-meter flying rock hits us sooner.

Time will tell.

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From The Editors Science

Imminent Collision of Milky Way with Nearby Galaxy Could Send our Solar System into Interstellar Space

Astrophysicists at Durham University’s Institute for Computational Cosmology in the UK and the University of Helsinki in Finland have predicted that a dwarf galaxy called the Large Magellanic Cloud (LMC), which weighs as much as 250 billion suns, will slam into the Milky Way in about two and a half billion years.

Should it happen for real, the cosmic collision will wreak havoc in our galactic neighborhood that could likely send our Solar System tumbling into the infinite void of interstellar space.

The massive impact is also likely to wake up the Milky Way’s hibernating blackhole, which will then begin devouring the surrounding gases and bloat to ten times its original size.

The awakened giant will spit out high-energy radiation in the galactic neighborhood in a dazzling display of cosmic eruptions.

“Barring any disasters, like a major disturbance to the solar system, our descendants, if any, are in for a treat: a spectacular display of cosmic fireworks as the newly awakened supermassive black hole at the center of our galaxy reacts by emitting jets of extremely bright energetic radiation,” said Prof. Carlos Frenk, study co-author and director of the Institute for Computational Cosmology at Durham.

While it may seem like a lot of fuss is being made over something that’s predicted to take place 2.5 billion years from now, “it is a very short time on cosmic timescales,” according to lead author Marius Cautun, a postdoctoral fellow at Durham’s.

The astrophysicists arrived at the scary conclusion after computer simulations of the LMC’s orbital trajectory revealed that the satellite galaxy, one among many orbiting our Milky Way, is headed for an imminent collision with the parent galaxy.

The simulations show that the LMC, which is now 163,000 lightyears away from our own galaxy and careening away from it at 900,000 miles per hour (1.4 million kilometers per hour), will eventually decelerate and reverse its trajectory to come crashing back into the Milky Way.

“The whole of the Milky Way will be shaken and the entire solar system could be ejected into outer space,” said Prof. Frenk.

“If that happens, I don’t see how our descendants, if we have any, will be able to withstand it,” he added.

Before the Durham discovery, astronomers believed that the Milky Way was facing total annihilation in about eight billion years’ time, but from an altogether different galaxy called Andromeda, five times more massive than the Large Magellanic Cloud.

Although the LMC bang is expected to happen much sooner, it may probably push the Milky Way out of harm’s way, thereby saving it from the bigger Andromeda, which is sure to spell our doom should it hit us.

“One of the by-products of the collision with the LMC is it will delay Armageddon,” explained Prof. Frenk.

“It will move the Milky Way a bit and that may buy us a couple of billion years,” he said.

“The LMC is big but it won’t completely destroy our galaxy,” he continued, going on to say that “it’ll produce these amazing fireworks, but it doesn’t have the mass to create a huge disturbance.”

He added: “The collision with Andromeda really will be Armageddon. That really will be the end of the Milky Way as we know it.”

The Milky Way is not a regular spiral galaxy because its inactive black hole is too small in the order of magnitude.

Also, our galaxy’s stellar halo has way too fewer heavy elements compared to regular spiral galaxies and the LMC is unusually large for a satellite galaxy.

However, all that will change when the LMC eventually smashes into the Milky Way.

“Once the LMC gets gobbled up by the Milky Way, our galaxy will become a beautiful, normal spiral,” Frenk said.

“Most of the halo will become stars from the LMC and the black hole will gorge on this sudden unexpected abundance of fuel and it will go berserk,” he added.

Durham University’s Alis Deason, one of the co-authors of the paper says that “many of the apparent ‘unusual’ properties of the Milky Way are temporary,” but “after the collision with the LMC, the Milky Way will look much more typical.”

Owing to the fact that there is way too much space between stars in a galaxy, the collision will most likely spare Earth any major destruction.

“This is not a ‘collision’ in the sense of a car crash,” said Scott Tremaine from the Institute for Advanced Study in New Jersey, who was not involved in the study.

“The effect of a merger with the Cloud on the Sun and Earth would be negligible, except perhaps that the night sky would look more interesting,” Tremaine added.

The paper entitled “The aftermath of the Great Collision between our Galaxy and the Large Magellanic Cloud” has been published in the journal “Monthly Notices of the Royal Astronomical Society.”

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From The Editors Science

China’s Lunar Probe Chang’e-4 Pulls Off Picture-Perfect Landing on Far Side of the Moon

In a never-before-attempted mission, China’s lunar lander, Chang’e-4, made a flawless touchdown on the far side of the Moon, state-run news channel China Central Television (CCTV) announced Thursday (Jan 3).

The China National Space Administration (CNSA) soft-landed the robotic probe in the targeted  Von Karman Crater – a huge southern hemisphere impact crater, measuring about 112 miles (180 kilometers) in diameter, located within an even bigger impact crater – the 1,600-mile (2,500-kilometer) South Pole-Aitken Basin.

Although Chang’e-4 had made it to the Moon’s orbit four days after launch, it began its final descent about three weeks later from an elliptical landing orbit almost 10 miles above the lunar surface.

When it was 100 meters above the landing site, the spacecraft briefly paused in its vertical approach, hovering over the landing zone to survey the topography below and selecting a relatively flat spot before resuming its descent.

The impeccable touchdown was appreciated by NASA Administrator Jim Bridenstine, who congratulated the mission team on “a successful landing on the far side of the Moon,” calling it “a first for humanity and an impressive accomplishment.”

The final approach phases were achieved autonomously by the spacecraft, as remote intervention from mission control in China was not possible during this stage of the mission.

“This is a great technological accomplishment as it was out of sight of Earth, so signals are relayed back by their orbiter, and most of the landing was actually done autonomously in difficult terrain,” Prof. Andrew Coates of UCL Mullard Space Science Laboratory (MSSL) in Surrey, England, was quoted by The Guardian as saying.

“The landing was almost vertical because of the surrounding hills,” Prof. Coates added.

Soon after landing, Chang’e-4 deployed its lunar rover named “Yutu-2” – Chinese for “Jade Rabbit-2” – which sent back the first ever close-up shot of the mysterious far side of our only known natural satellite.

The Chinese space agency also shared an image of Yutu-2’s deployment, along with pre- and post-landing images, all of which were relayed through the Queqiao (Magpie Bridge) satellite orbiting at the Earth-moon Lagrange point 2 beyond the far side.

Queqiao was, in fact, launched in May last year for the exact same purpose because direct communication with the far side of the Moon is impossible, what with the Moon’s entire mass blocking the exchange of direct signals to and from Earth.

The first image of the far side of the Moon (Image: China National Space Administration/Xinhua News Agency)
The first image of the far side of the Moon (Image: China National Space Administration/Xinhua News Agency)

Image of the far side surface taken during descent
Image of the far side surface taken during descent

While humans have glimpsed, and even mapped, the lunar far side in the past – thanks to NASA’s Apollo 8 mission half a century ago and the Soviet Luna 3 mission a decade prior to that – no spacecraft had ever touched down on the untrodden ground, until Chang’e-4 changed all of that.

In the past decade. or so, China has made rapid advances in space technology and is the only country in the world to have soft-landed a space vehicle on the Moon since the then Soviet Union’s 1976 Luna 24 mission to retrieve samples Moon soil.

China achieved the feat in December 2013, landing its Chang’e-3 rover on Mare Imbrium –  a vast lava plain within the Imbrium Basin on the near side of the Moon, becoming only the third country after Russia and the United States to achieve a lunar touchdown.

Encouraged by Chang’e-3’s success, China stepped up its lunar program for an even bigger mission, the first phase of which came to a successful conclusion with Chang’e-4’s Thursday landing on the targeted far side.

Comprising of a lander and a small rover, Chang’e-4 was, in fact, a backup spacecraft manufactured with the Chang’e-3.

It was only in 2015 that China announced its plans of using the spare space vehicle to launch something so complex that it had never been attempted before.

The nearly four-metric-ton Chang’e-4 has carried with it eight scientific instruments – four each on the lander and the rover.

The lander is equipped with the Landing Camera (LCAM), the Terrain Camera (TCAM), the Low-Frequency Spectrometer (LFS), and the Lunar Lander Neutrons and Dosimetry (LND).

And, the rover is carrying the Panoramic Camera (PCAM), the Lunar Penetrating Radar (LPR), the Visible and Near-Infrared Imaging Spectrometer (VNIS), and the Advanced Small Analyzer for Neutrals (ASAN).

Chang’e-4 has also carried a small experimental payload of silkworm eggs and seeds to check how they develop in the inhospitable lunar environment.

The huge amounts of science data and information these state-of-the-art space contraptions are capable of garnering will go a long way in helping researchers understand why the far side of our Moon is so vastly different from the side we’re familiar with.

For example, the lunar terrain on the tidally-locked near side is largely dark basaltic plains called the lunar maria, while the far side is mountainous and rugged and, hence, difficult to land anything on.

Since the Moon takes the same amount of time (28 days) to orbit our planet as it does to rotate once on its axis, we always get to see the same side of the natural satellite, with the opposite side forever hidden from view.

“Since the far side of the moon is shielded from electromagnetic interference from the Earth, it’s an ideal place to research the space environment and solar bursts, and the probe can ‘listen’ to the deeper reaches of the cosmos,” CNSA’s deputy director for the Lunar Exploration and Space Program Center, Tongjie Liu, was quoted by CNN as saying.

China’s next lunar run will be the Chang’e-5 sample-retrieval mission, which CNSA started preparing for in October 2014 when it launched the Chang’e-5T1 mission to run atmospheric re-entry tests on the -4Chang’e-5 capsule.

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From The Editors Science

NASA’s ‘New Horizons’ Spacecraft Makes Contact with Earth, Confirming New Year’s Day Flyby of Ultima Thule

When it was thirty-three minutes past midnight in New York; when the ball had already dropped in Times Square to usher in 2019; when parties were in full swing across the city; history was being made four billion miles out in space.

Technically, history happened in the blink of an eye, as NASA spacecraft New Horizons zipped past Ultima Thule, a tiny Kuiper Belt object (KBO) in the outer reaches of our solar system, at a lusty speed of 32,280 miles per hour – that’s 9 miles in a second, to put things in perspective.

However, confirmation of the historic flyby came only after an agonizing wait of six hours and eight minutes.

That’s how long it took the radio signal from the robotic craft to travel through the void of space before it was plucked from the air by a NASA deep space radio dish in Madrid.

Mission controllers at the John Hopkins University Applied Physics Laboratory in Maryland broke out in applause and cheers as the good news reached them; happy at the success, relieved that the unbearable suspense was over.

“We have a healthy spacecraft,” said Mission Operations Manager Alice Bowman, adding, “We’ve just accomplished the most distant flyby.”

However, Principal Mission Investigator Alan Stern is somewhat concerned that something could go wrong with the space-weary craft.

“Even though the spacecraft has performed perfectly now for almost 13 years, there’s always the chance that something could go amiss,” said Stern in a Tuesday press briefing.

New images of 2014 MU69 (Ultima Thule’s official designation), taken when New Horizons was still about 500,000 miles away, looks like a blurry peanut pod.

However, it was enough to give the mission scientists a refined estimation of its size, which they worked out to be roughly 22 miles (35 kilometers) long and 9.3 miles (15 kilometers) wide.

“Even though it’s a pixelated blob still,” said Project Scientist Dr. Harold Weaver, Jr., adding, “it’s a better pixelated blob.”

(Image source: JHUAPL/SwRI/NASA)
(Image source: JHUAPL/SwRI/NASA)

“The [lower resolution] images that come down this week will already reveal the basic geology and structure of Ultima for us, and we’re going to start writing our first scientific paper next week,” Stern told reporters.

Another question that the low-res pics helped answer was why Ultima Thule emitted a steady light as the NASA probe approached, instead of rhythmically dimming and brightening as a spinning object is expected to do.

It was because the spacecraft’s onboard camera was front-on with one of the poles of Ultima Thule, meaning the reflected sunlight was coming from the same side all along.

“It’s almost like a propeller blade,” said Weaver, adding, “That explains everything.”

One burning question, however, remains unanswered: Is Ultima Thule a single object, or two separate bodies orbiting in a tight configuration, or, two connected KBO’s, like conjoined twins?

However, Stern and Weaver are of the opinion that Ultima Thule is more likely a single object.

“If I’m wrong, I’ll tell you tomorrow,” Dr. Stern said.

“If it’s two separate objects, this would be an unprecedented situation, in terms of how close they’re orbiting one another,” he said.

“It’d be spectacular to see, and I’d love to see it, but I think the higher probability is that it’s a single body,” Stern added.

As more and more data is beamed back in the days and months ahead, scientists will be able to understand a lot about this ancient object, like, for example, the number of craters it has, if any; the composition of its surface material; whether there are any moons orbiting it, or rings around it,’ and more.

The New Year’s Day flyby has made Ultima Thule, which dates back to our solar system’s origin 4.5 billion years ago, the most distant object ever to be visited by a human-made spacecraft.

As distant and tiny as it is, this KBO has largely remained a mystery for scientists, which they are hoping to unravel more of with each passing day as New Horizons continues its data gathering mission.

“There’s so much that we can learn from close-up spacecraft observations that we’ll never learn from Earth, as the Pluto flyby demonstrated so spectacularly,” John Spencer, New Horizons science team member, had said in a statement in August.

New Horizons has been traveling through space ever since it was launched thirteen years ago on a Pluto flyby and study mission, which it accomplished back in 2015.

On February 28, 2007, New Horizons flew by Jupiter at a distance of 1.4 million miles (2.3 million kilometers), successfully sending back data about the planet’s atmosphere, moons, and magnetosphere.

The solar system giant gave it the gravitational slingshot it needed to boost its speed for the onward journey, which was spent in hibernation mode to keep its onboard systems preserved for the mission ahead.

The systems were, however, brought back online for brief annual check-ups before being put back to sleep.

More than a month before the 2015 rendezvous with Pluto, the probe was brought online one final time for a complete instruments and systems checkout before the close encounter.

The mission was a success as New Horizons was able to provide close-ups of the dwarf planet as well as scientifically invaluable data about its atmosphere, terrain, and environments.

Ultima Thule was never part of the original mission; it was selected as New Horizons next flyby destination about six months after the Pluto encounter.

New Horizons is well equipped to map 2014 MU69 in every which way possible, and although nothing is certain, the KBO could possibly be pockmarked with impact craters, pits, and sinkholes or, conversely, it could present a smooth surface.