Pluto features get names

Pluto’s first official surface-feature names are marked on this map, compiled from images and data gathered by NASA’s New Horizons spacecraft during its flight through the Pluto system in 2015. Image via NASA/JHUAPL/SwRI/Ross Beyer.

Pluto’s “heart” now bears the name of pioneering American astronomer Clyde Tombaugh, who discovered Pluto in 1930. And a crater on Pluto is now officially named after Venetia Burney, the British schoolgirl who in 1930 suggested the name “Pluto,” for the newly-discovered planet.

These are two of 14 official Pluto feature names approved by the International Astronomical Union (IAU), the internationally recognized authority for naming celestial bodies and their surface features.

These and other names were proposed by NASA’s New Horizons team following the first reconnaissance of Pluto and its moons by the New Horizons spacecraft in 2015. The team gathered many ideas during the “Our Pluto” online naming campaign in 2015.

The approved Pluto surface feature names are listed below, from a NASA statement. The names pay homage to the underworld mythology, pioneering space missions, historic pioneers who crossed new horizons in exploration, and scientists and engineers associated with Pluto and the Kuiper Belt.

– Tombaugh Regio honors Clyde Tombaugh (1906–1997), the U.S. astronomer who discovered Pluto in 1930 from Lowell Observatory in Arizona.

– Burney crater honors Venetia Burney (1918-2009), who as an 11-year-old schoolgirl suggested the name “Pluto” for Clyde Tombaugh’s newly discovered planet. Later in life she taught mathematics and economics.

– Sputnik Planitia is a large plain named for Sputnik 1, the first space satellite, launched by the Soviet Union in 1957.

– Tenzing Montes and Hillary Montes are mountain ranges honoring Tenzing Norgay (1914–1986) and Sir Edmund Hillary (1919–2008), the Indian/Nepali Sherpa and New Zealand mountaineer were the first to reach the summit of Mount Everest and return safely.

– Al-Idrisi Montes honors Ash-Sharif al-Idrisi (1100–1165/66), a noted Arab mapmaker and geographer whose landmark work of medieval geography is sometimes translated as “The Pleasure of Him Who Longs to Cross the Horizons.”

– Djanggawul Fossae defines a network of long, narrow depressions named for the Djanggawuls, three ancestral beings in indigenous Australian mythology who traveled between the island of the dead and Australia, creating the landscape and filling it with vegetation.

– Sleipnir Fossa is named for the powerful, eight-legged horse of Norse mythology that carried the god Odin into the underworld.

– Virgil Fossae honors Virgil, one of the greatest Roman poets and Dante’s fictional guide through hell and purgatory in the Divine Comedy.

– Adlivun Cavus is a deep depression named for Adlivun, the underworld in Inuit mythology.

– Hayabusa Terra is a large land mass saluting the Japanese spacecraft and mission (2003-2010) that performed the first asteroid sample return.

– Voyager Terra honors the pair of NASA spacecraft, launched in 1977, that performed the first “grand tour” of all four giant planets. The Voyager spacecraft are now probing the boundary between the Sun and interstellar space.

– Tartarus Dorsa is a ridge named for Tartarus, the deepest, darkest pit of the underworld in Greek mythology.

– Elliot crater recognizes James Elliot (1943-2011), an MIT researcher who pioneered the use of stellar occultations to study the solar system – leading to discoveries such as the rings of Uranus and the first detection of Pluto’s thin atmosphere.

Bottom line: the International Astronomical Union (IAU) gave official names to 14 geological features on Pluto.

Read more from NASA/New Horizons

from EarthSky http://ift.tt/2xRyyKh

Pluto’s first official surface-feature names are marked on this map, compiled from images and data gathered by NASA’s New Horizons spacecraft during its flight through the Pluto system in 2015. Image via NASA/JHUAPL/SwRI/Ross Beyer.

Pluto’s “heart” now bears the name of pioneering American astronomer Clyde Tombaugh, who discovered Pluto in 1930. And a crater on Pluto is now officially named after Venetia Burney, the British schoolgirl who in 1930 suggested the name “Pluto,” for the newly-discovered planet.

These are two of 14 official Pluto feature names approved by the International Astronomical Union (IAU), the internationally recognized authority for naming celestial bodies and their surface features.

These and other names were proposed by NASA’s New Horizons team following the first reconnaissance of Pluto and its moons by the New Horizons spacecraft in 2015. The team gathered many ideas during the “Our Pluto” online naming campaign in 2015.

The approved Pluto surface feature names are listed below, from a NASA statement. The names pay homage to the underworld mythology, pioneering space missions, historic pioneers who crossed new horizons in exploration, and scientists and engineers associated with Pluto and the Kuiper Belt.

– Tombaugh Regio honors Clyde Tombaugh (1906–1997), the U.S. astronomer who discovered Pluto in 1930 from Lowell Observatory in Arizona.

– Burney crater honors Venetia Burney (1918-2009), who as an 11-year-old schoolgirl suggested the name “Pluto” for Clyde Tombaugh’s newly discovered planet. Later in life she taught mathematics and economics.

– Sputnik Planitia is a large plain named for Sputnik 1, the first space satellite, launched by the Soviet Union in 1957.

– Tenzing Montes and Hillary Montes are mountain ranges honoring Tenzing Norgay (1914–1986) and Sir Edmund Hillary (1919–2008), the Indian/Nepali Sherpa and New Zealand mountaineer were the first to reach the summit of Mount Everest and return safely.

– Al-Idrisi Montes honors Ash-Sharif al-Idrisi (1100–1165/66), a noted Arab mapmaker and geographer whose landmark work of medieval geography is sometimes translated as “The Pleasure of Him Who Longs to Cross the Horizons.”

– Djanggawul Fossae defines a network of long, narrow depressions named for the Djanggawuls, three ancestral beings in indigenous Australian mythology who traveled between the island of the dead and Australia, creating the landscape and filling it with vegetation.

– Sleipnir Fossa is named for the powerful, eight-legged horse of Norse mythology that carried the god Odin into the underworld.

– Virgil Fossae honors Virgil, one of the greatest Roman poets and Dante’s fictional guide through hell and purgatory in the Divine Comedy.

– Adlivun Cavus is a deep depression named for Adlivun, the underworld in Inuit mythology.

– Hayabusa Terra is a large land mass saluting the Japanese spacecraft and mission (2003-2010) that performed the first asteroid sample return.

– Voyager Terra honors the pair of NASA spacecraft, launched in 1977, that performed the first “grand tour” of all four giant planets. The Voyager spacecraft are now probing the boundary between the Sun and interstellar space.

– Tartarus Dorsa is a ridge named for Tartarus, the deepest, darkest pit of the underworld in Greek mythology.

– Elliot crater recognizes James Elliot (1943-2011), an MIT researcher who pioneered the use of stellar occultations to study the solar system – leading to discoveries such as the rings of Uranus and the first detection of Pluto’s thin atmosphere.

Bottom line: the International Astronomical Union (IAU) gave official names to 14 geological features on Pluto.

Read more from NASA/New Horizons

from EarthSky http://ift.tt/2xRyyKh

Last night was fantastic for auroras

Photo by Sacha Layos in Fairbanks, Alaska.

Activity on the sun this week prompted strong geomagnetic activity Thursday night (the night of September 7-8, 2017). Sacha Layos in Fairbanks, Alaska observed this outburst of auroras on Friday morning and captured the wonderful image above. Spaceweather.com said:

The debris from Wednesday’s monster X9-class solar flare reached Earth [Thursday night] and its impact was everything forecasters expected. A severe G4-class geomagnetic storm commenced, sparking auroras over Scandinavia so bright they actually stopped traffic … The storm was still going strong as night fell over North America. For a while, Northern Lights spilled across the Canadian border into the USA as far south as Arkansas–in addition to Maine, Connecticut, New York, Kentucky, Indiana, Missouri, Delaware, Michigan, North Carolina, Ohio, Iowa, Maryland, Virginia, Vermont, North and South Dakota, and other states.

The geomagnetic storm may not be over. Especially if you’re at a northerly latitude, watch when night falls on Friday!

from EarthSky http://ift.tt/2eKLERK

Photo by Sacha Layos in Fairbanks, Alaska.

Activity on the sun this week prompted strong geomagnetic activity Thursday night (the night of September 7-8, 2017). Sacha Layos in Fairbanks, Alaska observed this outburst of auroras on Friday morning and captured the wonderful image above. Spaceweather.com said:

The debris from Wednesday’s monster X9-class solar flare reached Earth [Thursday night] and its impact was everything forecasters expected. A severe G4-class geomagnetic storm commenced, sparking auroras over Scandinavia so bright they actually stopped traffic … The storm was still going strong as night fell over North America. For a while, Northern Lights spilled across the Canadian border into the USA as far south as Arkansas–in addition to Maine, Connecticut, New York, Kentucky, Indiana, Missouri, Delaware, Michigan, North Carolina, Ohio, Iowa, Maryland, Virginia, Vermont, North and South Dakota, and other states.

The geomagnetic storm may not be over. Especially if you’re at a northerly latitude, watch when night falls on Friday!

from EarthSky http://ift.tt/2eKLERK

Are you SMART? The Department of Defense Will Fund Your Education

The SMART Scholarship program is a scholarship for service created to recruit and retain the next generation of science and technology leaders. The latest iteration of the program is accepting applications until Dec. 1, 2017.

from http://ift.tt/2gOVq6f

The SMART Scholarship program is a scholarship for service created to recruit and retain the next generation of science and technology leaders. The latest iteration of the program is accepting applications until Dec. 1, 2017.

from http://ift.tt/2gOVq6f

Wholegrains and bowel cancer – what you need to know

Eating plenty of wholegrains cuts your risk of bowel cancer, according to a new report.

And it seems we can reap the benefits without making wild changes to our diets (unless your diet is mainly hot dogs and fry-ups).

The news comes from a report produced by the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR), outlining the latest evidence on how we can reduce our risk of bowel cancer.

It focusses on the effects of diet, weight, physical activity and alcohol on bowel cancer risk. And with bowel cancer being the fourth most common cancer in the UK, finding ways to reduce our risk of the disease are important.

The WCRF studies all the evidence on a potential cause of cancer and decides whether that evidence is strong enough to support recommendations on ways we can reduce our risk.

For bowel cancer, we already recommend that people include plenty of wholegrain options in their diet. So the new report is welcome.

But what is a wholegrain? We take a look at what they are and how you can get more into your diet.

What’s new in the report?

The proven things you can do to reduce the risk of bowel cancer have remained constant over the years, and this report reinforces that.

What was true yesterday is even more true today.

Copy this link and share our graphic

The most interesting finding from the new report is that for the first time, the WCRF team looked at the effect of wholegrains on their own (a food high in fibre and other nutrients).

Previously, WRCF has only looked at the combined effects of foods high in fibre, and found that eating more of these can reduce the risk of bowel cancer. But other research looking at different types of high fibre foods has found that the strongest evidence for reducing bowel cancer risk comes from wholegrains.

And the conclusion of the latest report is that there is now strong evidence that both wholegrains specifically and a high fibre diet in general reduce the risk of bowel cancer.

What’s a wholegrain?

A grain is the seed of a plant. Grains are made up of three parts: the bran, germ and endosperm. During the milling process, the bran and germ are lost, leaving whiter refined grains, such as white flour. This part of the grain is mainly an energy store, so refined grains give you carbohydrates and some protein but not much else.

A wholegrain still has its bran and germ, such as in wholemeal flour. Most of the nutrients and fibre are found in these bits, which means that wholegrains are naturally more nutritious than refined grains. And this is the likely reason why wholegrains are linked with a reduced risk of bowel cancer.

Copy this link and share our graphic

How do wholegrains cut bowel cancer risk?

This is most likely down to the fibre they contain.

Fibre increases the size of your poos, dilutes them, and helps them move through your system quicker. This reduces the amount of time harmful chemicals stay in contact with the bowel, potentially reducing the damage caused to cells.

Fibre may also help gut bacteria produce helpful chemicals that change the conditions in the bowel.

All these things could help to reduce the risk of bowel cancer and is why foods high in fibre have been linked with bowel cancer for many years now.

But other things in wholegrains, such as phenolic acids, could also be playing a role, and may partly explain why wholegrains seem to show a strong link on their own.

Eating more high-fibre wholegrains and fewer refined grains can help you keep a healthy weight by feeling fuller for longer. This not only cuts the risk of bowel cancer, but 12 other cancers too.

How much wholegrain should we be eating?

The UK’s dietary guidelines recommend that we base our meals on starchy foods, and where possible choose wholegrain versions. But there aren’t any specifics on how much we should eat.

The WCRF report found, based on all the studies published on wholegrains and bowel cancer to date, that for every 90g of wholegrains eaten daily, there was a 17% reduction in bowel cancer risk. This is what’s known as a relative risk (more on that here), which tells us how much more, or in this case less, likely the disease is to occur in one group (people eating 90g of wholegrains), compared to another (people who didn’t eat wholegrains). And because this is for every 90g eaten it underlines that the benefits increase the more wholegrains you eat.

This isn’t a guarantee though, because relative risk can’t tell us about the overall likelihood of bowel cancer being diagnosed in any one person. But with more than 41,000 cases of bowel cancer diagnosed in the UK each year, a 17% reduction in risk could make a sizeable dent.

For example, we already know that eating more foods containing fibre, of which some will be wholegrains, could lead to 5,100 fewer cases of bowel cancer each year in the UK.

So 90g isn’t a magic number, and it doesn’t mean you need to start weighing your food. The key thing here is that by switching to wholegrain versions of your everyday starchy foods you can easily meet this amount and more. And every bit counts.

Copy this link and share our graphic

So whether it’s switching to wholemeal breads, opting for a wholegrain cereal at breakfast (such as porridge oats, shredded wheat, or Weetabix (or your supermarket’s own brand), having plain popcorn instead of crisps or choosing brown rice and whole wheat pasta, all these swaps can make a big difference. If you don’t eat many wholegrains, try switching for just one meal a day.

Wholegrains vs. hot dogs

It’s not just wholegrains we should be thinking about when it comes to bowel cancer and diet.

The latest report also found strong evidence that processed and red meat increase the risk of bowel cancer. This isn’t a new finding, and is something we’ve written about before.

This doesn’t mean you have to be a vegetarian. Too much meat isn’t very good for you but eating it a few times a week probably won’t do much harm. It’s all about balance.

Tried-and-true advice

Beyond diet, this report reinforced the strong evidence that being overweight and drinking too much alcohol also increase the risk of bowel cancer, while being more physically active decreases the risk, adding more weight to previous similar findings.

So our advice remains the same: choose wholegrains and other fibre-rich foods, eat plenty of fruit and veg, keep active, limit your alcohol, and keep a healthy weight.

The science is clear: it’s putting it into practice that’s trickier. We have plenty of hints and tips on our website and we’re also working for better government policy to make being healthier easier for everyone.

Emma Shields is a health information officer at Cancer Research UK

from Cancer Research UK – Science blog http://ift.tt/2xTBJlg

Eating plenty of wholegrains cuts your risk of bowel cancer, according to a new report.

And it seems we can reap the benefits without making wild changes to our diets (unless your diet is mainly hot dogs and fry-ups).

The news comes from a report produced by the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR), outlining the latest evidence on how we can reduce our risk of bowel cancer.

It focusses on the effects of diet, weight, physical activity and alcohol on bowel cancer risk. And with bowel cancer being the fourth most common cancer in the UK, finding ways to reduce our risk of the disease are important.

The WCRF studies all the evidence on a potential cause of cancer and decides whether that evidence is strong enough to support recommendations on ways we can reduce our risk.

For bowel cancer, we already recommend that people include plenty of wholegrain options in their diet. So the new report is welcome.

But what is a wholegrain? We take a look at what they are and how you can get more into your diet.

What’s new in the report?

The proven things you can do to reduce the risk of bowel cancer have remained constant over the years, and this report reinforces that.

What was true yesterday is even more true today.

Copy this link and share our graphic

The most interesting finding from the new report is that for the first time, the WCRF team looked at the effect of wholegrains on their own (a food high in fibre and other nutrients).

Previously, WRCF has only looked at the combined effects of foods high in fibre, and found that eating more of these can reduce the risk of bowel cancer. But other research looking at different types of high fibre foods has found that the strongest evidence for reducing bowel cancer risk comes from wholegrains.

And the conclusion of the latest report is that there is now strong evidence that both wholegrains specifically and a high fibre diet in general reduce the risk of bowel cancer.

What’s a wholegrain?

A grain is the seed of a plant. Grains are made up of three parts: the bran, germ and endosperm. During the milling process, the bran and germ are lost, leaving whiter refined grains, such as white flour. This part of the grain is mainly an energy store, so refined grains give you carbohydrates and some protein but not much else.

A wholegrain still has its bran and germ, such as in wholemeal flour. Most of the nutrients and fibre are found in these bits, which means that wholegrains are naturally more nutritious than refined grains. And this is the likely reason why wholegrains are linked with a reduced risk of bowel cancer.

Copy this link and share our graphic

How do wholegrains cut bowel cancer risk?

This is most likely down to the fibre they contain.

Fibre increases the size of your poos, dilutes them, and helps them move through your system quicker. This reduces the amount of time harmful chemicals stay in contact with the bowel, potentially reducing the damage caused to cells.

Fibre may also help gut bacteria produce helpful chemicals that change the conditions in the bowel.

All these things could help to reduce the risk of bowel cancer and is why foods high in fibre have been linked with bowel cancer for many years now.

But other things in wholegrains, such as phenolic acids, could also be playing a role, and may partly explain why wholegrains seem to show a strong link on their own.

Eating more high-fibre wholegrains and fewer refined grains can help you keep a healthy weight by feeling fuller for longer. This not only cuts the risk of bowel cancer, but 12 other cancers too.

How much wholegrain should we be eating?

The UK’s dietary guidelines recommend that we base our meals on starchy foods, and where possible choose wholegrain versions. But there aren’t any specifics on how much we should eat.

The WCRF report found, based on all the studies published on wholegrains and bowel cancer to date, that for every 90g of wholegrains eaten daily, there was a 17% reduction in bowel cancer risk. This is what’s known as a relative risk (more on that here), which tells us how much more, or in this case less, likely the disease is to occur in one group (people eating 90g of wholegrains), compared to another (people who didn’t eat wholegrains). And because this is for every 90g eaten it underlines that the benefits increase the more wholegrains you eat.

This isn’t a guarantee though, because relative risk can’t tell us about the overall likelihood of bowel cancer being diagnosed in any one person. But with more than 41,000 cases of bowel cancer diagnosed in the UK each year, a 17% reduction in risk could make a sizeable dent.

For example, we already know that eating more foods containing fibre, of which some will be wholegrains, could lead to 5,100 fewer cases of bowel cancer each year in the UK.

So 90g isn’t a magic number, and it doesn’t mean you need to start weighing your food. The key thing here is that by switching to wholegrain versions of your everyday starchy foods you can easily meet this amount and more. And every bit counts.

Copy this link and share our graphic

So whether it’s switching to wholemeal breads, opting for a wholegrain cereal at breakfast (such as porridge oats, shredded wheat, or Weetabix (or your supermarket’s own brand), having plain popcorn instead of crisps or choosing brown rice and whole wheat pasta, all these swaps can make a big difference. If you don’t eat many wholegrains, try switching for just one meal a day.

Wholegrains vs. hot dogs

It’s not just wholegrains we should be thinking about when it comes to bowel cancer and diet.

The latest report also found strong evidence that processed and red meat increase the risk of bowel cancer. This isn’t a new finding, and is something we’ve written about before.

This doesn’t mean you have to be a vegetarian. Too much meat isn’t very good for you but eating it a few times a week probably won’t do much harm. It’s all about balance.

Tried-and-true advice

Beyond diet, this report reinforced the strong evidence that being overweight and drinking too much alcohol also increase the risk of bowel cancer, while being more physically active decreases the risk, adding more weight to previous similar findings.

So our advice remains the same: choose wholegrains and other fibre-rich foods, eat plenty of fruit and veg, keep active, limit your alcohol, and keep a healthy weight.

The science is clear: it’s putting it into practice that’s trickier. We have plenty of hints and tips on our website and we’re also working for better government policy to make being healthier easier for everyone.

Emma Shields is a health information officer at Cancer Research UK

from Cancer Research UK – Science blog http://ift.tt/2xTBJlg

How nuclear war would affect Earth’s climate

Image via Stanford/StrahilDimitrov/Getty Images.

Via Stanford University, a Q&A with Paul N. Edwards, CISAC’s William J. Perry Fellow in International Security at Stanford’s Freeman Spogli Institute for International Studies.

There is no denying that nuclear war would have a huge impact on the environment. Though daily headlines worry about the safety of nations and citizens, little has been said about the impact on climate change. In Part Two of our series on the consequences of nuclear war, science and technology historian Paul N. Edwards tells us about the effects of nuclear war on Earth itself – and how they would affect humans.

In the nuclear conversation, what are we not talking about that we should be?

We are not talking enough about the climatic effects of nuclear war.

The “nuclear winter” theory of the mid-1980s played a significant role in the arms reductions of that period. But with the collapse of the Soviet Union and the reduction of U.S. and Russian nuclear arsenals, this aspect of nuclear war has faded from view. That’s not good. In the mid-2000s, climate scientists such as Alan Robock (Rutgers) took another look at nuclear winter theory. This time around, they used much-improved and much more detailed climate models than those available 20 years earlier. They also tested the potential effects of smaller nuclear exchanges.

The result: an exchange involving just 50 nuclear weapons — the kind of thing we might see in an India-Pakistan war, for example — could loft 5 billion kilograms of smoke, soot and dust high into the stratosphere. That’s enough to cool the entire planet by about 2 degrees Fahrenheit (1.25 degrees Celsius) — about where we were during the Little Ice Age of the 17th century. Growing seasons could be shortened enough to create really significant food shortages. So the climatic effects of even a relatively small nuclear war would be planet-wide.

What about a larger-scale conflict?

A U.S.-Russia war currently seems unlikely, but if it were to occur, hundreds or even thousands of nuclear weapons might be launched. The climatic consequences would be catastrophic: global average temperatures would drop as much as 12 degrees Fahrenheit (7 degrees Celsius) for up to several years — temperatures last seen during the great ice ages. Meanwhile, smoke and dust circulating in the stratosphere would darken the atmosphere enough to inhibit photosynthesis, causing disastrous crop failures, widespread famine and massive ecological disruption.

The effect would be similar to that of the giant meteor believed to be responsible for the extinction of the dinosaurs. This time, we would be the dinosaurs.

Many people are concerned about North Korea’s advancing missile capabilities. Is nuclear war likely in your opinion?

At this writing, I think we are closer to a nuclear war than we have been since the early 1960s. In the North Korea case, both Kim Jong-un and President Trump are bullies inclined to escalate confrontations. President Trump lacks impulse control, and there are precious few checks on his ability to initiate a nuclear strike. We have to hope that our generals, both inside and outside the White House, can rein him in.

North Korea would most certainly “lose” a nuclear war with the United States. But many millions would die, including hundreds of thousands of Americans currently living in South Korea and Japan (probable North Korean targets). Such vast damage would be wrought in Korea, Japan and Pacific island territories (such as Guam) that any “victory” wouldn’t deserve the name. Not only would that region be left with horrible suffering amongst the survivors; it would also immediately face famine and rampant disease. Radioactive fallout from such a war would spread around the world, including to the U.S.

It has been more than 70 years since the last time a nuclear bomb was used in warfare. What would be the effects on the environment and on human health today?

To my knowledge, most of the changes in nuclear weapons technology since the 1950s have focused on making them smaller and lighter, and making delivery systems more accurate, rather than on changing their effects on the environment or on human health. So-called “battlefield” weapons with lower explosive yields are part of some arsenals now — but it’s quite unlikely that any exchange between two nuclear powers would stay limited to these smaller, less destructive bombs.

Larger bombs can flatten cities. Many if not most people within the blast radius —
which can be up to 10 miles — would die instantly. Those who survived would wish they hadn’t, since most would die later of severe burns or awful cancers. Radioactive fallout from these weapons’ debris clouds would reach the stratosphere, where it would travel worldwide, potentially contaminating crops and livestock as well as causing radiation sickness and cancer directly. Later, this fallout would cause genetic mutations in plants, animals and human beings, as it has in the vicinity of the Chernobyl nuclear accident.

Nuclear explosions would also cause immense fires. The smoke from burning buildings, oil and gas fields, refineries, chemical factories, and industrial facilities would be highly toxic. Forest fires would engulf large areas. These effects would destroy more property and kill more people.

You have asked whether it is legal to start a nuclear war, given its environmental effects. Tell us about the impacts of such a war on climate change.

So far, nuclear weapons have been treated as a last resort. If leaders are rational, political scientists have always argued, they will never launch first because they know they’ll be destroyed, or at least badly damaged, by the retaliatory attack.

The laws of war require belligerent nations to avoid damage and casualties to neutral nations and non-combatants. But medium- and large-scale nuclear conflicts would have severe, and global, climatic effects. Most or all neutral nations and non-combatants would be damaged and would suffer casualties. So a strong argument can be made that any such war would be illegal (a point I owe to discussions with Scott Sagan and Bill Perry).

My hope is that as the much slower catastrophe of global climate change continues to grow, the full scale of the climatic damage that could be done by nuclear war will also become a serious issue for international negotiation.

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Bottom line: Q&A with Stanford scientist on the catastrophic effects nuclear war would have on Earth’s climate and environment.

from EarthSky http://ift.tt/2xTFMhv

Image via Stanford/StrahilDimitrov/Getty Images.

Via Stanford University, a Q&A with Paul N. Edwards, CISAC’s William J. Perry Fellow in International Security at Stanford’s Freeman Spogli Institute for International Studies.

There is no denying that nuclear war would have a huge impact on the environment. Though daily headlines worry about the safety of nations and citizens, little has been said about the impact on climate change. In Part Two of our series on the consequences of nuclear war, science and technology historian Paul N. Edwards tells us about the effects of nuclear war on Earth itself – and how they would affect humans.

In the nuclear conversation, what are we not talking about that we should be?

We are not talking enough about the climatic effects of nuclear war.

The “nuclear winter” theory of the mid-1980s played a significant role in the arms reductions of that period. But with the collapse of the Soviet Union and the reduction of U.S. and Russian nuclear arsenals, this aspect of nuclear war has faded from view. That’s not good. In the mid-2000s, climate scientists such as Alan Robock (Rutgers) took another look at nuclear winter theory. This time around, they used much-improved and much more detailed climate models than those available 20 years earlier. They also tested the potential effects of smaller nuclear exchanges.

The result: an exchange involving just 50 nuclear weapons — the kind of thing we might see in an India-Pakistan war, for example — could loft 5 billion kilograms of smoke, soot and dust high into the stratosphere. That’s enough to cool the entire planet by about 2 degrees Fahrenheit (1.25 degrees Celsius) — about where we were during the Little Ice Age of the 17th century. Growing seasons could be shortened enough to create really significant food shortages. So the climatic effects of even a relatively small nuclear war would be planet-wide.

What about a larger-scale conflict?

A U.S.-Russia war currently seems unlikely, but if it were to occur, hundreds or even thousands of nuclear weapons might be launched. The climatic consequences would be catastrophic: global average temperatures would drop as much as 12 degrees Fahrenheit (7 degrees Celsius) for up to several years — temperatures last seen during the great ice ages. Meanwhile, smoke and dust circulating in the stratosphere would darken the atmosphere enough to inhibit photosynthesis, causing disastrous crop failures, widespread famine and massive ecological disruption.

The effect would be similar to that of the giant meteor believed to be responsible for the extinction of the dinosaurs. This time, we would be the dinosaurs.

Many people are concerned about North Korea’s advancing missile capabilities. Is nuclear war likely in your opinion?

At this writing, I think we are closer to a nuclear war than we have been since the early 1960s. In the North Korea case, both Kim Jong-un and President Trump are bullies inclined to escalate confrontations. President Trump lacks impulse control, and there are precious few checks on his ability to initiate a nuclear strike. We have to hope that our generals, both inside and outside the White House, can rein him in.

North Korea would most certainly “lose” a nuclear war with the United States. But many millions would die, including hundreds of thousands of Americans currently living in South Korea and Japan (probable North Korean targets). Such vast damage would be wrought in Korea, Japan and Pacific island territories (such as Guam) that any “victory” wouldn’t deserve the name. Not only would that region be left with horrible suffering amongst the survivors; it would also immediately face famine and rampant disease. Radioactive fallout from such a war would spread around the world, including to the U.S.

It has been more than 70 years since the last time a nuclear bomb was used in warfare. What would be the effects on the environment and on human health today?

To my knowledge, most of the changes in nuclear weapons technology since the 1950s have focused on making them smaller and lighter, and making delivery systems more accurate, rather than on changing their effects on the environment or on human health. So-called “battlefield” weapons with lower explosive yields are part of some arsenals now — but it’s quite unlikely that any exchange between two nuclear powers would stay limited to these smaller, less destructive bombs.

Larger bombs can flatten cities. Many if not most people within the blast radius —
which can be up to 10 miles — would die instantly. Those who survived would wish they hadn’t, since most would die later of severe burns or awful cancers. Radioactive fallout from these weapons’ debris clouds would reach the stratosphere, where it would travel worldwide, potentially contaminating crops and livestock as well as causing radiation sickness and cancer directly. Later, this fallout would cause genetic mutations in plants, animals and human beings, as it has in the vicinity of the Chernobyl nuclear accident.

Nuclear explosions would also cause immense fires. The smoke from burning buildings, oil and gas fields, refineries, chemical factories, and industrial facilities would be highly toxic. Forest fires would engulf large areas. These effects would destroy more property and kill more people.

You have asked whether it is legal to start a nuclear war, given its environmental effects. Tell us about the impacts of such a war on climate change.

So far, nuclear weapons have been treated as a last resort. If leaders are rational, political scientists have always argued, they will never launch first because they know they’ll be destroyed, or at least badly damaged, by the retaliatory attack.

The laws of war require belligerent nations to avoid damage and casualties to neutral nations and non-combatants. But medium- and large-scale nuclear conflicts would have severe, and global, climatic effects. Most or all neutral nations and non-combatants would be damaged and would suffer casualties. So a strong argument can be made that any such war would be illegal (a point I owe to discussions with Scott Sagan and Bill Perry).

My hope is that as the much slower catastrophe of global climate change continues to grow, the full scale of the climatic damage that could be done by nuclear war will also become a serious issue for international negotiation.

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Bottom line: Q&A with Stanford scientist on the catastrophic effects nuclear war would have on Earth’s climate and environment.

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Star of the week: Delta Cephei

Like lights in a dark tunnel, stars in the distant universe become fainter as they are farther away. But, because they pulsate at a particular rate always correlated to their intrinsic brightnesses, Cepheid variable stars reveal their own true distances. Image via The Last Word on Nothing

At the southeast corner of the house-shaped constellation Cepheus the King, there is an intriguing variable star called Delta Cephei. With clocklike precison, this rather faint star doubles in brightness, fades to a minimum and then doubles in brightness every 5.36 days. You can see it change over a period of days. The entire cycle is visible to the eye alone in a dark-enough sky. This star and others like it have secured a place as important standard candles for establishing the scale of the galaxy and universe.

Delta Cephei itself looms large in the history of astronomy. An entire class of supergiant stars – called Cepheid variables – is named in this star’s honor.

Like Delta Cephei, Cepheid variable stars dependably change their brightnesses over regular intervals. The time period can range from about one to 100 days, depending on the star’s luminosity or intrinsic brightness. Astronomers have learned that – the longer the cycle – the greater the intrinsic brightness of the star. This knowledge is a powerful tool in astronomy. Follow the links below to learn more about this interesting star.

How do Cepheid variable stars help measure cosmic distances?

How can I spot Delta Cephei in the night sky?

How can I watch Delta Cephei vary in brightness?

This graph is what astronomers call a light curve. It’s the light curve of Delta Cephei, which, as dependably as a fine clock, doubles in brightness and then fades again every 5.366341 days days.

How do Cepheid variable stars help measure cosmic distances? Because Delta Cephei and other stars in its class vary so dependably – and because the cycle of their brightness change is tied so strongly to their intrinsic brightnesses – these stars can be used to measure distances across space. Astronomers call objects that can be used in this way standard candles.

How does it work? First, they carefully measure the rates of these stars’ pulsations. Unfortunately, the distances to very few – if any – Cepheid variable stars are close enough to measure directly by stellar parallax. However, the approximate distances of Cepheid variables in relatively nearby star clusters have been determined indirectly by the spectroscopic method (sometimes called by the misnomer spectroscopic parallax). After watching many Cepheid variables pulsate – and knowing their approximate distances via the spectroscopic method – they know how bright a Cepheid variable of a particular intrinsic brightness should look at a given distance from Earth.

Armed with this knowledge, astronomers watch the pulsations of this class of stars in distant space. They can deduce the stars’ intrinsic brightnesses because of their rates of pulsation. Then they can infer the distances to more faraway stars by their apparent magnitude. Because light dims by the inverse square law, astronomers know a star of a given luminosity (intrinsic brightness) would appear 1/16th as bright at 4 times the distance, 1/64th as bright at 8 times the distance or 1/100th as bright at 10 times the distance.

Why are these stars varying in brightness, by the way? The variations are thought to be actual pulsations as the star itself expands and then contracts.

Cepheid variable stars can be seen up to a distance of 20 million light-years. The nearest galaxy is about 2 million light-years away – and the most distant are billions of light-years away. So these stars don’t get you far in measuring distances across space. Still, since astronomers learned the secrets of their pulsation, these stars have been vital to astronomy.

The astronomer Henrietta Leavitt discovered Cepheid variables in 1912. In 1923, the astronomer Edwin Hubble used Cepheid variable stars to determine that the so-called Andromeda nebula is actually a giant galaxy lying beyond the confines of our Milky Way. That knowledge released us from the confines of a single galaxy and gave us the vast universe we know today.

How can I spot Delta Cephei in the night sky? This star is circumpolar – always above the horizon – in the northern half of the United States.

Location of star Delta Cephei within constellation Cepheus.

Even so, this star is much easier to see when it’s high in the northern sky on autumn and winter evenings. You can find Cepheus by way of the Big Dipper. First, use the Big Dipper “pointer stars” to locate Polaris, the North Star. Then jump beyond the Polaris by a fist-width to land on Cepheus.

You’ll see the constellation Cepheus the King close his wife, Cassiopeia the Queen, her signature W or M-shaped figurine of stars making her the flashier of the two constellations. They’re high in your northern sky on November and December evenings.

International Astronomical Union chart showing constellation Cepheus.

How can I watch Delta Cephei vary in brightness? The real answer to that question is: time and patience. But two stars lodging near Delta Cephei on the sky’s dome – Epsilon Cephei and Zeta Cephei – match the low and high ends of Delta Cephei’s brightness scale. That fact should help you watch Delta Cephei change.

So look back at the chart at the top of this post, and locate the stars Epsilon and Zeta Cephei. At its faintest, Delta Cephei is as dim as the fainter star, Epsilon Cephei. At its brightest, Delta Cephei matches the brightness of the brighter star, Zeta Cephei.

Have fun!

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Bottom line: The star Delta Cephei brightens and fades with clocklike precision every 5.36 days.

from EarthSky http://ift.tt/TM6Zye

Like lights in a dark tunnel, stars in the distant universe become fainter as they are farther away. But, because they pulsate at a particular rate always correlated to their intrinsic brightnesses, Cepheid variable stars reveal their own true distances. Image via The Last Word on Nothing

At the southeast corner of the house-shaped constellation Cepheus the King, there is an intriguing variable star called Delta Cephei. With clocklike precison, this rather faint star doubles in brightness, fades to a minimum and then doubles in brightness every 5.36 days. You can see it change over a period of days. The entire cycle is visible to the eye alone in a dark-enough sky. This star and others like it have secured a place as important standard candles for establishing the scale of the galaxy and universe.

Delta Cephei itself looms large in the history of astronomy. An entire class of supergiant stars – called Cepheid variables – is named in this star’s honor.

Like Delta Cephei, Cepheid variable stars dependably change their brightnesses over regular intervals. The time period can range from about one to 100 days, depending on the star’s luminosity or intrinsic brightness. Astronomers have learned that – the longer the cycle – the greater the intrinsic brightness of the star. This knowledge is a powerful tool in astronomy. Follow the links below to learn more about this interesting star.

How do Cepheid variable stars help measure cosmic distances?

How can I spot Delta Cephei in the night sky?

How can I watch Delta Cephei vary in brightness?

This graph is what astronomers call a light curve. It’s the light curve of Delta Cephei, which, as dependably as a fine clock, doubles in brightness and then fades again every 5.366341 days days.

How do Cepheid variable stars help measure cosmic distances? Because Delta Cephei and other stars in its class vary so dependably – and because the cycle of their brightness change is tied so strongly to their intrinsic brightnesses – these stars can be used to measure distances across space. Astronomers call objects that can be used in this way standard candles.

How does it work? First, they carefully measure the rates of these stars’ pulsations. Unfortunately, the distances to very few – if any – Cepheid variable stars are close enough to measure directly by stellar parallax. However, the approximate distances of Cepheid variables in relatively nearby star clusters have been determined indirectly by the spectroscopic method (sometimes called by the misnomer spectroscopic parallax). After watching many Cepheid variables pulsate – and knowing their approximate distances via the spectroscopic method – they know how bright a Cepheid variable of a particular intrinsic brightness should look at a given distance from Earth.

Armed with this knowledge, astronomers watch the pulsations of this class of stars in distant space. They can deduce the stars’ intrinsic brightnesses because of their rates of pulsation. Then they can infer the distances to more faraway stars by their apparent magnitude. Because light dims by the inverse square law, astronomers know a star of a given luminosity (intrinsic brightness) would appear 1/16th as bright at 4 times the distance, 1/64th as bright at 8 times the distance or 1/100th as bright at 10 times the distance.

Why are these stars varying in brightness, by the way? The variations are thought to be actual pulsations as the star itself expands and then contracts.

Cepheid variable stars can be seen up to a distance of 20 million light-years. The nearest galaxy is about 2 million light-years away – and the most distant are billions of light-years away. So these stars don’t get you far in measuring distances across space. Still, since astronomers learned the secrets of their pulsation, these stars have been vital to astronomy.

The astronomer Henrietta Leavitt discovered Cepheid variables in 1912. In 1923, the astronomer Edwin Hubble used Cepheid variable stars to determine that the so-called Andromeda nebula is actually a giant galaxy lying beyond the confines of our Milky Way. That knowledge released us from the confines of a single galaxy and gave us the vast universe we know today.

How can I spot Delta Cephei in the night sky? This star is circumpolar – always above the horizon – in the northern half of the United States.

Location of star Delta Cephei within constellation Cepheus.

Even so, this star is much easier to see when it’s high in the northern sky on autumn and winter evenings. You can find Cepheus by way of the Big Dipper. First, use the Big Dipper “pointer stars” to locate Polaris, the North Star. Then jump beyond the Polaris by a fist-width to land on Cepheus.

You’ll see the constellation Cepheus the King close his wife, Cassiopeia the Queen, her signature W or M-shaped figurine of stars making her the flashier of the two constellations. They’re high in your northern sky on November and December evenings.

International Astronomical Union chart showing constellation Cepheus.

How can I watch Delta Cephei vary in brightness? The real answer to that question is: time and patience. But two stars lodging near Delta Cephei on the sky’s dome – Epsilon Cephei and Zeta Cephei – match the low and high ends of Delta Cephei’s brightness scale. That fact should help you watch Delta Cephei change.

So look back at the chart at the top of this post, and locate the stars Epsilon and Zeta Cephei. At its faintest, Delta Cephei is as dim as the fainter star, Epsilon Cephei. At its brightest, Delta Cephei matches the brightness of the brighter star, Zeta Cephei.

Have fun!

Enjoying EarthSky? Sign up for our free daily newsletter today!

Bottom line: The star Delta Cephei brightens and fades with clocklike precision every 5.36 days.

from EarthSky http://ift.tt/TM6Zye

Moon and Uranus in Pisces September 8

Tonight – September 8, 2017 – the waning gibbous moon and Uranus, the seventh planet outward from the sun, are near each other on the sky’s dome, in front of the constellation Pisces the Fishes. Although Uranus will remain within Pisces’ borders for the rest of this year, the moon will leave Pisces after a day or two. Around the world, the moon and Uranus will rise over the eastern horizon by around mid-evening, though you can find out a more specific time from an astronomical almanac.

With the moon so bright and so close to Uranus on the sky’s dome, you’re not likely to glimpse Uranus with the unaided eye. But keep reading. We give you an idea of its location, and links to detailed charts, in this post.

View larger. | José Luis Ruiz Gómez in Almería, Spain captured Uranus near the moon on January 15, 2016. He wrote: “Why not try?”

Uranus was the first planet to be discovered by the telescope, by William Hershel on March 13, 1781. At a distance of about 19 astronomical units from Earth at present, this world is pretty easy to see through binoculars – if you know exactly where to look.

People with good vision – and good charts (scroll to bottom of page) – can see Uranus with the unaided eye on dark, moonless nights.

In your quest to locate Uranus, first make friends with the constellation Pisces after the moon leaves the evening sky, starting in a few more days. Familiar with the Great Square of Pegasus? If so, jump off from there to the constellation Pisces the Fishes. Then with a good sky chart and binoculars you just might catch Uranus, the seventh planet from the sun.

First find the signpost known as the Great Square of Pegasus. That’s your jumping off spot for finding Pisces’ place in the great celestial sea. Click here for a larger chart.

EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store

Bottom line: The moon and the planet Uranus both reside in front of the constellation Pisces the Fishes on September 8, 2017.

from EarthSky http://ift.tt/2gMQEWU

Tonight – September 8, 2017 – the waning gibbous moon and Uranus, the seventh planet outward from the sun, are near each other on the sky’s dome, in front of the constellation Pisces the Fishes. Although Uranus will remain within Pisces’ borders for the rest of this year, the moon will leave Pisces after a day or two. Around the world, the moon and Uranus will rise over the eastern horizon by around mid-evening, though you can find out a more specific time from an astronomical almanac.

With the moon so bright and so close to Uranus on the sky’s dome, you’re not likely to glimpse Uranus with the unaided eye. But keep reading. We give you an idea of its location, and links to detailed charts, in this post.

View larger. | José Luis Ruiz Gómez in Almería, Spain captured Uranus near the moon on January 15, 2016. He wrote: “Why not try?”

Uranus was the first planet to be discovered by the telescope, by William Hershel on March 13, 1781. At a distance of about 19 astronomical units from Earth at present, this world is pretty easy to see through binoculars – if you know exactly where to look.

People with good vision – and good charts (scroll to bottom of page) – can see Uranus with the unaided eye on dark, moonless nights.

In your quest to locate Uranus, first make friends with the constellation Pisces after the moon leaves the evening sky, starting in a few more days. Familiar with the Great Square of Pegasus? If so, jump off from there to the constellation Pisces the Fishes. Then with a good sky chart and binoculars you just might catch Uranus, the seventh planet from the sun.

First find the signpost known as the Great Square of Pegasus. That’s your jumping off spot for finding Pisces’ place in the great celestial sea. Click here for a larger chart.

EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store

Bottom line: The moon and the planet Uranus both reside in front of the constellation Pisces the Fishes on September 8, 2017.

from EarthSky http://ift.tt/2gMQEWU