Many people saw the waning moon and dazzlingly bright Venus earlier this week (photos here), and Bruce McClure at EarthSky had mentioned there was also an opportunity to catch the innermost and most elusive of the bright planets, Mercury, near the moon on December 5, 2018. He wrote:
The planet Mercury is much fainter, lower in the sky than Venus, near the exceedingly thin crescent moon on Wednesday morning, December 5. To see them on this morning, unless you’re eagle-eyed and have a very clear sky, you might need binoculars.
We did hear from a few people who spotted Mercury with the eye alone this week, while up early driving to work, for example. The photos on this page are the only ones we’ve received so far. But we’re expecting more! That’s because Mercury is brightening day by day now. It’s also coming up earlier by the day. By the middle of December, Mercury will be a fine morning object in the eastern sky before dawn.
It would be lots of fun to spot it now and watch it brighten! Look very low in the east – below bright Venus – before the sun comes up.
Moon and Mercury from Ken Gallagher Photography in Lake Havasu City, Arizona on December 5, 2018.
Bottom line: Photos of the elusive planet Mercury near the moon in early December, 2018.
Many people saw the waning moon and dazzlingly bright Venus earlier this week (photos here), and Bruce McClure at EarthSky had mentioned there was also an opportunity to catch the innermost and most elusive of the bright planets, Mercury, near the moon on December 5, 2018. He wrote:
The planet Mercury is much fainter, lower in the sky than Venus, near the exceedingly thin crescent moon on Wednesday morning, December 5. To see them on this morning, unless you’re eagle-eyed and have a very clear sky, you might need binoculars.
We did hear from a few people who spotted Mercury with the eye alone this week, while up early driving to work, for example. The photos on this page are the only ones we’ve received so far. But we’re expecting more! That’s because Mercury is brightening day by day now. It’s also coming up earlier by the day. By the middle of December, Mercury will be a fine morning object in the eastern sky before dawn.
It would be lots of fun to spot it now and watch it brighten! Look very low in the east – below bright Venus – before the sun comes up.
Moon and Mercury from Ken Gallagher Photography in Lake Havasu City, Arizona on December 5, 2018.
Bottom line: Photos of the elusive planet Mercury near the moon in early December, 2018.
A ‘universal cancer test’ is big news today, with headlinesclaiming that the test will be able to detect any cancer in just 10 minutes.
While the science behind the headlines is exciting, the reality is the test is a long way from being used to diagnose cancer.
Professor Paul Pharoah, from the University of Cambridge, urges caution, saying it’s unknown if the innovative idea will be useful in a clinical setting, as some news reports suggested.
That’s because using a blood test to confirm that people with advanced cancer have cancer is very different to using that same test to detect the earliest hints of cancer in otherwise healthy people.
The new method
Researchers at the University of Queensland in Australia developed a new way to pick up differences between the DNA of cancer cells and healthy cells.
These differences stem from tiny molecules called methyl groups, which are naturally added to DNA inside cells. These molecules are usually spread evenly across the DNA in cells, but in cancer cells they tend form clusters at different points.
It turns out that in a chemical solution, the tightly clustered methyl groups fold the DNA into a unique shape, which can stick to solid surfaces like gold. This ‘universal fingerprint’ changes the properties of the solution, which can be measured in the lab.
The Australian team tested blood samples from 100 patients with breast and bowel cancers that had already spread to other tissues. The results were then compared to 45 samples taken from people without cancer.
A key point to remember is that the study almost exclusively used samples taken from patients whose cancer had already spread. Patients with these advanced cancers often have more cancer DNA circulating in their blood, which would make it easier to pick up.
“When developing a test like this, researchers will almost always start with samples from patients whose cancer has spread. Because if the test can’t pick up metastatic cancer then it’s not going to work for early stage disease,” says Pharoah. “It’s the first step in the process.”
In initial experiments using blood samples, the scientists correctly distinguished between healthy and cancer samples 73% of the time using one test and 83% of the time with another.
“How accurate a test looks varies massively depending on what samples are being used and how the experiment is run,” says Pharoah. “Which is why it’s too soon to get excited, we need to wait for results on more clinically relevant samples of early stage cancer.”
How do you assess a cancer test?
Researchers look at 3 main things when assessing a new diagnostic test.
Sensitivity – the probability that you test positive if you have the disease. This will vary depending on what’s being defined as the disease. This study mainly looked at samples from advanced cancers, the sensitivity is likely to be different for early stage disease.
Specificity – the probability that you test negative if you do not have the disease.
Accuracy – the proportion of samples correctly classified by the test. It’s a combined measure of sensitivity and specificity. It’s dependent on how experiments are run, and so can be misleading in news stories.
The test that made headlines today wasn’t sensitive enough to detect very low levels of DNA that had the “cancer signature” artificially added. The researchers noted in the paper that with the current method used: “We may not be able to detect cancer on a very early stage.”
What’s next?
To understand if the test could help diagnose cancer, the next step is to use it on more relevant samples.
Pharoah says this could involve collecting samples from a large group of people with non-specific symptoms that may be cancer. Once they had gone through routine diagnostic tests, researchers could then use the new technique to see how well it picked up the cancers that were diagnosed. But studies like this need to be done on a large scale and take a long time to get solid results.
Dr Ankur Chakravarthy, one of the researchers involved in the study agreed, telling Forbes that it’s too soon to know how clinically useful the test might be. “Just how useful this test will be for routine clinical use will depend on extensive testing in the general population to see how often it gets things wrong.”
It’s always exciting to see new methods being developed that could one day be used to help diagnose cancer. But the reality is there’s a long way to go before we know if this method will be accurate enough to be useful in the clinic.
“Often these tests get overhyped very early on in their development, which can be extremely unhelpful,” says Pharoah. “It’s a long road from discovering a new technology to actually having something that could benefit patients, and this test is right at the start of that journey.”
Katie
Reference
Sina, et al. (2018) Epigenetically reprogrammed methylation landscape drives the DNA self-assembly and serves as a universal cancer biomarker. Nature Comms. DOI: 10.1038/s41467-018-07214-w
from Cancer Research UK – Science blog https://ift.tt/2zITXst
A ‘universal cancer test’ is big news today, with headlinesclaiming that the test will be able to detect any cancer in just 10 minutes.
While the science behind the headlines is exciting, the reality is the test is a long way from being used to diagnose cancer.
Professor Paul Pharoah, from the University of Cambridge, urges caution, saying it’s unknown if the innovative idea will be useful in a clinical setting, as some news reports suggested.
That’s because using a blood test to confirm that people with advanced cancer have cancer is very different to using that same test to detect the earliest hints of cancer in otherwise healthy people.
The new method
Researchers at the University of Queensland in Australia developed a new way to pick up differences between the DNA of cancer cells and healthy cells.
These differences stem from tiny molecules called methyl groups, which are naturally added to DNA inside cells. These molecules are usually spread evenly across the DNA in cells, but in cancer cells they tend form clusters at different points.
It turns out that in a chemical solution, the tightly clustered methyl groups fold the DNA into a unique shape, which can stick to solid surfaces like gold. This ‘universal fingerprint’ changes the properties of the solution, which can be measured in the lab.
The Australian team tested blood samples from 100 patients with breast and bowel cancers that had already spread to other tissues. The results were then compared to 45 samples taken from people without cancer.
A key point to remember is that the study almost exclusively used samples taken from patients whose cancer had already spread. Patients with these advanced cancers often have more cancer DNA circulating in their blood, which would make it easier to pick up.
“When developing a test like this, researchers will almost always start with samples from patients whose cancer has spread. Because if the test can’t pick up metastatic cancer then it’s not going to work for early stage disease,” says Pharoah. “It’s the first step in the process.”
In initial experiments using blood samples, the scientists correctly distinguished between healthy and cancer samples 73% of the time using one test and 83% of the time with another.
“How accurate a test looks varies massively depending on what samples are being used and how the experiment is run,” says Pharoah. “Which is why it’s too soon to get excited, we need to wait for results on more clinically relevant samples of early stage cancer.”
How do you assess a cancer test?
Researchers look at 3 main things when assessing a new diagnostic test.
Sensitivity – the probability that you test positive if you have the disease. This will vary depending on what’s being defined as the disease. This study mainly looked at samples from advanced cancers, the sensitivity is likely to be different for early stage disease.
Specificity – the probability that you test negative if you do not have the disease.
Accuracy – the proportion of samples correctly classified by the test. It’s a combined measure of sensitivity and specificity. It’s dependent on how experiments are run, and so can be misleading in news stories.
The test that made headlines today wasn’t sensitive enough to detect very low levels of DNA that had the “cancer signature” artificially added. The researchers noted in the paper that with the current method used: “We may not be able to detect cancer on a very early stage.”
What’s next?
To understand if the test could help diagnose cancer, the next step is to use it on more relevant samples.
Pharoah says this could involve collecting samples from a large group of people with non-specific symptoms that may be cancer. Once they had gone through routine diagnostic tests, researchers could then use the new technique to see how well it picked up the cancers that were diagnosed. But studies like this need to be done on a large scale and take a long time to get solid results.
Dr Ankur Chakravarthy, one of the researchers involved in the study agreed, telling Forbes that it’s too soon to know how clinically useful the test might be. “Just how useful this test will be for routine clinical use will depend on extensive testing in the general population to see how often it gets things wrong.”
It’s always exciting to see new methods being developed that could one day be used to help diagnose cancer. But the reality is there’s a long way to go before we know if this method will be accurate enough to be useful in the clinic.
“Often these tests get overhyped very early on in their development, which can be extremely unhelpful,” says Pharoah. “It’s a long road from discovering a new technology to actually having something that could benefit patients, and this test is right at the start of that journey.”
Katie
Reference
Sina, et al. (2018) Epigenetically reprogrammed methylation landscape drives the DNA self-assembly and serves as a universal cancer biomarker. Nature Comms. DOI: 10.1038/s41467-018-07214-w
from Cancer Research UK – Science blog https://ift.tt/2zITXst
“I don’t believe it,” said Donald Trump when asked about the fourth national climate assessment, authored by 13 government agencies and hundreds of the US’s top climate scientists. His administration had tried to hide the report, publishing it on Black Friday when many Americans were either recovering from a Thanksgiving food coma or stampeding department store sales.
The administration’s plan backfired badly – the latest alarming climate science report became front-page news. Numerous Republican politicians were asked about it on TV news and politics shows, and their answers demonstrated that Trump’s climate science denial continues to pervade the GOP.
Republican party leaders’ answers ranged from platitudes – such as “our climate always changes” and “innovation” is all that is needed to solve the problem – to accusations that “a lot of these scientists are driven by the money”.
Addressing the latter point, one of the report’s lead authors, Prof Katharine Hayhoe, noted that many of its contributors were “paid zero dollars” and estimated that in the time she devoted to the assessment, she could have written eight of her own papers. Conversely, GOP politicians and operatives are paid millions of dollars annually by the fossil fuel industry. Some people are clearly driven by the money, and it’s not climate scientists.
Trump’s comments did not stop at disbelief – he also appeared to shift blame to other countries and tout the US’s clean air and water.
“You’re going to have to have China, and Japan, and all of Asia, and all of these other countries – you know, [the report] addresses our country. Right now, we’re at the cleanest we’ve ever been, and that’s very important to me. But if we’re clean but every other place on Earth is dirty, that’s not so good. So, I want clean air, I want clean water – very important,” the president said.
These comments confuse climate change with air pollution, but the two are connected. The national climate assessment report pointed out that climate change was exacerbating wildfires, which in turn create air pollution. The Camp fire in November produced so much smoke that California had the worst air quality in the world at the time.
A key figure showed that climate change had approximately doubled the area burned by wildfires in the western US, and the report noted that – contrary to the administration’s frequent claims – this increase was “more closely related to climate factors than to fire suppression, local fire management, or other non-climate factors”.
The cumulative forest area burned by wildfires in the western US between 1984 and 2015. Photograph: Fourth National Climate Assessment Report
“I don’t believe it,” said Donald Trump when asked about the fourth national climate assessment, authored by 13 government agencies and hundreds of the US’s top climate scientists. His administration had tried to hide the report, publishing it on Black Friday when many Americans were either recovering from a Thanksgiving food coma or stampeding department store sales.
The administration’s plan backfired badly – the latest alarming climate science report became front-page news. Numerous Republican politicians were asked about it on TV news and politics shows, and their answers demonstrated that Trump’s climate science denial continues to pervade the GOP.
Republican party leaders’ answers ranged from platitudes – such as “our climate always changes” and “innovation” is all that is needed to solve the problem – to accusations that “a lot of these scientists are driven by the money”.
Addressing the latter point, one of the report’s lead authors, Prof Katharine Hayhoe, noted that many of its contributors were “paid zero dollars” and estimated that in the time she devoted to the assessment, she could have written eight of her own papers. Conversely, GOP politicians and operatives are paid millions of dollars annually by the fossil fuel industry. Some people are clearly driven by the money, and it’s not climate scientists.
Trump’s comments did not stop at disbelief – he also appeared to shift blame to other countries and tout the US’s clean air and water.
“You’re going to have to have China, and Japan, and all of Asia, and all of these other countries – you know, [the report] addresses our country. Right now, we’re at the cleanest we’ve ever been, and that’s very important to me. But if we’re clean but every other place on Earth is dirty, that’s not so good. So, I want clean air, I want clean water – very important,” the president said.
These comments confuse climate change with air pollution, but the two are connected. The national climate assessment report pointed out that climate change was exacerbating wildfires, which in turn create air pollution. The Camp fire in November produced so much smoke that California had the worst air quality in the world at the time.
A key figure showed that climate change had approximately doubled the area burned by wildfires in the western US, and the report noted that – contrary to the administration’s frequent claims – this increase was “more closely related to climate factors than to fire suppression, local fire management, or other non-climate factors”.
The cumulative forest area burned by wildfires in the western US between 1984 and 2015. Photograph: Fourth National Climate Assessment Report
An international team of scientists says it has measured all of the starlight ever produced throughout the 13.7-billion-year history of the observable universe. Sounds wild, right? But the new study was published November 30, 2018 in the peer-reviewed journal Science. According to the new measurement, the number of photons (particles of visible light) that have escaped into space since the universe began – after being emitted by stars – translates to 4×1084.
Or put another way …
That’s 4,000,000,000,000,000,000,000,000,000,000,000,000,000,000, 000,000,000,000,000,000,000,000,000,000,000,000,000,000 photons of light.
Clemson College of Science astrophysicist Marco Ajello – who is featured in the video above – is lead author of the new paper. He said in a statement:
… we were able to measure the entire amount of starlight ever emitted. This has never been done before.
And, of course, there are many variables, so this number is just a ballpark figure. Still, it’s impressive. How did scientists arrive at this number?
This is part of the Hubble Ultra Deep Field. It shows some of the oldest starlight ever seen in our universe. Image via NASA/ ESA.
Astrophysicists believe that our universe started in a Big Bang, some 13.7 billion years ago. They think it started forming stars very quickly after its birth, when it was only a few hundred million years old. Since then, the universe has become a star-making tour de force.
In the universe today, there are about two trillion galaxies and about a trillion-trillion stars.
Measuring all of the starlight in this vast universe is clearly a daunting task. This team of scientists says it did it by analyzing data from NASA’s Fermi Gamma-ray Space Telescope.
The new calculations are based on measurements of the extragalactic background light, also known as the EBL. You can think of the EBL as a cosmic fog composed of all the ultraviolet, visible and infrared light ever emitted by stars. If you could measure the EBL, you’d have taken a huge step toward measuring all the starlight in the universe.
But obtaining this measurement hasn’t been easy.
Abhishek Desai is a physics and astronomy grad student at Clemson, and a co-author on the new paper. Desai said:
Scientists have tried to measure the EBL for a long time. However, very bright foregrounds like the zodiacal light (which is light scattered by dust in the solar system) rendered this measurement very challenging.
The new study used Fermi Gamma-ray Space Telescope data to analyze the light from 739 blazars – supermassive black holes that emit powerful jets of gamma rays – whose light was emitted in the ancient universe and has taken billions of years to arrive at Earth. The scientists said:
Blazars are galaxies containing supermassive black holes that are able to release narrowly collimated jets of energetic particles that leap out of their galaxies and streak across the cosmos at nearly the speed of light. When one of these jets happens to be pointed directly at Earth, it is detectable even when originating from extremely far away. Gamma ray photons produced within the jets eventually collide with the cosmic fog [or EBL], leaving an observable imprint.
And thus the researchers were able to measure the density of the EBL not just at a given place, but also at a given time in the history of the universe.
Or check out the video below, which also describes more about how this study was conducted:
The upshot is that, until a future team of scientists corrects this number (a high probability since, as we all know, science is a process, not a body of facts), we now have a number to describe the total photons of light emitted by stars since the universe began.
That number again … 4,000,000,000,000,000,000,000,000,000,000,000,000,000,000, 000,000,000,000,000,000,000,000,000,000,000,000,000,000.
Despite this stupendously large number, the researchers said, it’s interesting to note that – with the exception of the light that comes from our own sun and galaxy – the rest of the starlight that reaches Earth is exceedingly dim. It’s equivalent to a 60-watt light bulb viewed in complete darkness from about 2.5 miles (4 km) away.
Why is this? It’s because our universe is almost incomprehensibly huge. The dimness of starlight also explains why the sky is dark at night, other than light from the moon, visible stars and the faint glow of the Milky Way.
An image of ancient starlight from what was called the Ultra-Deep Survey, via University of Nottingham.
Bottom line: How much starlight has our universe produced? According to a new study, stars have radiated 4×1084 photons since the start of the universe 13.7 billion years ago. That’s the number 4 with 84 zeros behind it.
An international team of scientists says it has measured all of the starlight ever produced throughout the 13.7-billion-year history of the observable universe. Sounds wild, right? But the new study was published November 30, 2018 in the peer-reviewed journal Science. According to the new measurement, the number of photons (particles of visible light) that have escaped into space since the universe began – after being emitted by stars – translates to 4×1084.
Or put another way …
That’s 4,000,000,000,000,000,000,000,000,000,000,000,000,000,000, 000,000,000,000,000,000,000,000,000,000,000,000,000,000 photons of light.
Clemson College of Science astrophysicist Marco Ajello – who is featured in the video above – is lead author of the new paper. He said in a statement:
… we were able to measure the entire amount of starlight ever emitted. This has never been done before.
And, of course, there are many variables, so this number is just a ballpark figure. Still, it’s impressive. How did scientists arrive at this number?
This is part of the Hubble Ultra Deep Field. It shows some of the oldest starlight ever seen in our universe. Image via NASA/ ESA.
Astrophysicists believe that our universe started in a Big Bang, some 13.7 billion years ago. They think it started forming stars very quickly after its birth, when it was only a few hundred million years old. Since then, the universe has become a star-making tour de force.
In the universe today, there are about two trillion galaxies and about a trillion-trillion stars.
Measuring all of the starlight in this vast universe is clearly a daunting task. This team of scientists says it did it by analyzing data from NASA’s Fermi Gamma-ray Space Telescope.
The new calculations are based on measurements of the extragalactic background light, also known as the EBL. You can think of the EBL as a cosmic fog composed of all the ultraviolet, visible and infrared light ever emitted by stars. If you could measure the EBL, you’d have taken a huge step toward measuring all the starlight in the universe.
But obtaining this measurement hasn’t been easy.
Abhishek Desai is a physics and astronomy grad student at Clemson, and a co-author on the new paper. Desai said:
Scientists have tried to measure the EBL for a long time. However, very bright foregrounds like the zodiacal light (which is light scattered by dust in the solar system) rendered this measurement very challenging.
The new study used Fermi Gamma-ray Space Telescope data to analyze the light from 739 blazars – supermassive black holes that emit powerful jets of gamma rays – whose light was emitted in the ancient universe and has taken billions of years to arrive at Earth. The scientists said:
Blazars are galaxies containing supermassive black holes that are able to release narrowly collimated jets of energetic particles that leap out of their galaxies and streak across the cosmos at nearly the speed of light. When one of these jets happens to be pointed directly at Earth, it is detectable even when originating from extremely far away. Gamma ray photons produced within the jets eventually collide with the cosmic fog [or EBL], leaving an observable imprint.
And thus the researchers were able to measure the density of the EBL not just at a given place, but also at a given time in the history of the universe.
Or check out the video below, which also describes more about how this study was conducted:
The upshot is that, until a future team of scientists corrects this number (a high probability since, as we all know, science is a process, not a body of facts), we now have a number to describe the total photons of light emitted by stars since the universe began.
That number again … 4,000,000,000,000,000,000,000,000,000,000,000,000,000,000, 000,000,000,000,000,000,000,000,000,000,000,000,000,000.
Despite this stupendously large number, the researchers said, it’s interesting to note that – with the exception of the light that comes from our own sun and galaxy – the rest of the starlight that reaches Earth is exceedingly dim. It’s equivalent to a 60-watt light bulb viewed in complete darkness from about 2.5 miles (4 km) away.
Why is this? It’s because our universe is almost incomprehensibly huge. The dimness of starlight also explains why the sky is dark at night, other than light from the moon, visible stars and the faint glow of the Milky Way.
An image of ancient starlight from what was called the Ultra-Deep Survey, via University of Nottingham.
Bottom line: How much starlight has our universe produced? According to a new study, stars have radiated 4×1084 photons since the start of the universe 13.7 billion years ago. That’s the number 4 with 84 zeros behind it.
The Solfatara volcanic crater is part of the Phlegraean Fields near Naples. Image via Futurity/Getty Images.
A new study suggests that the Phlegraean Fields — one of the most active and volatile volcanic regions in the world — is at the early stage of a new cycle that could culminate in another gigantic eruption. But it won’t happen for several thousand years, according to new research, published November 14, 2018, in the journal Science Advances.
The Phlegraean Fields, near the bustling metropolis of Naples, Italy, is one of the world’s most active and volatile volcanic regions. Its calderas were formed by enormous eruptions that took place 39,000 and 15,000 years ago, in addition to countless minor eruptions. Smaller volcanoes also erupted repeatedly during the period in between. The Phlegraean Fields have become more active again in recent years.
The Phlegraean Fields, to the west of Naples, Italy. The area of the caldera consists of 24 craters and volcanic edifices, most of which are under water.
The researchers explained that volcanoes go though cycles. The cycle begins with the accumulation of magma – molten rock – in a large reservoir in the Earth’s crust, a process that takes millennia. Long periods of dormancy and small eruptions characterize this stage. A further injection of magma into the magma chamber triggers an enormous eruption. The reservoir empties abruptly, the roof collapses, a new caldera forms, and the cycle begins anew.
In the Phlegraean Fields study, rock samples from 23 earlier eruptions provided the researchers with evidence of the start of a new cycle. In particular, rock material from Monte Nuovo, which last erupted in 1538, resembles rock ejected just before the last two major eruptions.
Despite their new findings, the researchers can’t predict exactly when the next major eruption at the Phlegraean Fields may occur. Francesca Forni of ETH Zurich is the study lead author. She said in a statement:
But we do not have to worry about a catastrophic eruption in the next 20,000 years. The magma reservoir underneath the Phlegraean Fields fills up only very slowly. We, the next generations, and perhaps the entire human race will not be here to witness a massive eruption.
A fumarole at the Phlegraean Fields; painting by Michael Wutky (1780s). Image via Wikipedia.
For the research, the volcanologists took advantage of the fact that the chemical composition of minerals from magmatic rock stores information on the conditions under which it originates. By comparing the chemical signatures of rock from different eras, scientists can reconstruct the conditions in the crust at the time of its formation. This allows them to determine the current stage of the magma system. The volcanologists also created a model of the cycle. Olivier Bachmann, a professor at ETH Zurich, is a study co-author. He said:
We can reconstruct from past eruptions the rhythm that supervolcanoes have, and hopefully predict where they stand in their cycle.
The Bay of Naples with the island of Ischia (left) and the scarred Phlegraean Fields. Naples lies at the foot of Mount Vesuvius (center). Image via Futurity/ESA.
Although a major eruption is thousands of years away, it’s important to continue to monitor the evolution of the Phlegraean Fields on a sustained basis, said Forni. She warns that even a small eruption, which can occur during the early stages of a cycle, would wreak havoc on the region.
Some of the early warning signs of an impending eruption of a magma chamber are land elevation and changes in the composition of the gases the Phlegraean Fields emits.
A massive volcanic eruption would be devastating not only for the Naples region but the entire world. Supervolcanoes have caused short-term climate catastrophes, crop failure, and famines in the past. The eruption of the Indonesian supervolcano Tambora in 1815 is a well-documented example: the following summer was dubbed the “year without a summer,” and even places as far away as Switzerland suffered crop failure.
Bottom line: A new study suggests that Italy’s Phlegraean Fields is readying for a catastrophic eruption, but not for thousands of years.
The Solfatara volcanic crater is part of the Phlegraean Fields near Naples. Image via Futurity/Getty Images.
A new study suggests that the Phlegraean Fields — one of the most active and volatile volcanic regions in the world — is at the early stage of a new cycle that could culminate in another gigantic eruption. But it won’t happen for several thousand years, according to new research, published November 14, 2018, in the journal Science Advances.
The Phlegraean Fields, near the bustling metropolis of Naples, Italy, is one of the world’s most active and volatile volcanic regions. Its calderas were formed by enormous eruptions that took place 39,000 and 15,000 years ago, in addition to countless minor eruptions. Smaller volcanoes also erupted repeatedly during the period in between. The Phlegraean Fields have become more active again in recent years.
The Phlegraean Fields, to the west of Naples, Italy. The area of the caldera consists of 24 craters and volcanic edifices, most of which are under water.
The researchers explained that volcanoes go though cycles. The cycle begins with the accumulation of magma – molten rock – in a large reservoir in the Earth’s crust, a process that takes millennia. Long periods of dormancy and small eruptions characterize this stage. A further injection of magma into the magma chamber triggers an enormous eruption. The reservoir empties abruptly, the roof collapses, a new caldera forms, and the cycle begins anew.
In the Phlegraean Fields study, rock samples from 23 earlier eruptions provided the researchers with evidence of the start of a new cycle. In particular, rock material from Monte Nuovo, which last erupted in 1538, resembles rock ejected just before the last two major eruptions.
Despite their new findings, the researchers can’t predict exactly when the next major eruption at the Phlegraean Fields may occur. Francesca Forni of ETH Zurich is the study lead author. She said in a statement:
But we do not have to worry about a catastrophic eruption in the next 20,000 years. The magma reservoir underneath the Phlegraean Fields fills up only very slowly. We, the next generations, and perhaps the entire human race will not be here to witness a massive eruption.
A fumarole at the Phlegraean Fields; painting by Michael Wutky (1780s). Image via Wikipedia.
For the research, the volcanologists took advantage of the fact that the chemical composition of minerals from magmatic rock stores information on the conditions under which it originates. By comparing the chemical signatures of rock from different eras, scientists can reconstruct the conditions in the crust at the time of its formation. This allows them to determine the current stage of the magma system. The volcanologists also created a model of the cycle. Olivier Bachmann, a professor at ETH Zurich, is a study co-author. He said:
We can reconstruct from past eruptions the rhythm that supervolcanoes have, and hopefully predict where they stand in their cycle.
The Bay of Naples with the island of Ischia (left) and the scarred Phlegraean Fields. Naples lies at the foot of Mount Vesuvius (center). Image via Futurity/ESA.
Although a major eruption is thousands of years away, it’s important to continue to monitor the evolution of the Phlegraean Fields on a sustained basis, said Forni. She warns that even a small eruption, which can occur during the early stages of a cycle, would wreak havoc on the region.
Some of the early warning signs of an impending eruption of a magma chamber are land elevation and changes in the composition of the gases the Phlegraean Fields emits.
A massive volcanic eruption would be devastating not only for the Naples region but the entire world. Supervolcanoes have caused short-term climate catastrophes, crop failure, and famines in the past. The eruption of the Indonesian supervolcano Tambora in 1815 is a well-documented example: the following summer was dubbed the “year without a summer,” and even places as far away as Switzerland suffered crop failure.
Bottom line: A new study suggests that Italy’s Phlegraean Fields is readying for a catastrophic eruption, but not for thousands of years.
Wesley Loftis in Clarksville, Virginia, caught this Geminid meteor during the 2017 shower.
The Geminid meteor shower – always a highlight of the meteor year – will peak around the mornings of December 13 and 14, 2018. The Geminids are a very reliable shower if you watch at the peak time of night (centered on about 2 a.m. for all parts of the globe) and if you watch in a dark sky. The meteors tend to be bold, white and quick! This shower favors Earth’s Northern Hemisphere, but it’s visible from the Southern Hemisphere, too. The curious rock comet called 3200 Phaethon is the parent body of this shower.
On a dark night, near the peak, you can often catch 50 or more meteors per hour.
Why are the Geminids best around 2 a.m.? It’s because that’s when the shower’s radiant point – the point in our sky from which the meteors seem to radiate – is highest in the sky. As a general rule, the higher the constellation Gemini the Twins climbs into your sky, the more Geminid meteors you’re likely to see. The Geminids’ radiant point is highest around 2 a.m.
Special equipment? None needed. Just find a dark, open sky and maybe bring a sleeping bag to keep warm. Plan to sprawl back in a hammock, lawn chair, pile of hay or blanket on the ground.
Martin Marthadinata in Surabaya, East Java, Indonesia, caught this Geminid fireball in 2014, coming from the shower’s radiant point near the star Castor.
The Geminids radiate from near the bright star Castor in the constellation Gemini, in the east on December evenings, highest around 2 a.m. Learn more about the Geminids’ radiant point.
This Geminids’ radiant point nearly coincides with the bright star Castor in Gemini. That’s a chance alignment, of course, as Castor lies about 52 light-years away while these meteors burn up in the upper atmosphere, some 60 miles (100 km) above Earth’s surface.
Castor is noticeably near another bright star, the golden star Pollux of Gemini. It’s fun to spot them, but you don’t need to find a meteor shower’s radiant point in order see the meteors.
Instead, meteors in annual showers appear in all parts of the sky. It’s even possible to have your back to the constellation Gemini and see a Geminid meteor fly by.
That’s why, when you’re meteor-watching, it’s good to bring along a buddy. Then two of you can watch in different directions. When someone sees one, they can call out “meteor!” This technique will let you see more meteors than one person watching alone will see.
Be sure to give yourself at least an hour of observing time. It takes about 20 minutes for your eyes to adapt to the dark.
Be aware that meteors often come in spurts, interspersed with lulls.
Painting of 1860 earthgrazer fireball by Frederic Edwin Church. Image via Wikimedia Commons.
Earthgrazers possible possible at early evening. Okay, we said you’ll likely see the most meteors at a time of night centered around 2 a.m. You won’t see as many Geminid meteors in early evening, when the constellation Gemini sits close to the eastern horizon.
But the evening hours are the best time to try to catch an earthgrazer meteor.
An earthgrazer is a slow-moving, long-lasting meteor that travels horizontally across the sky.
Earthgrazers are rarely seen but prove to be especially memorable, if you should be lucky enough to catch one.
Radar images of near-Earth asteroid 3200 Phaethon generated by astronomers at the Arecibo Observatory on December 17, 2017. The 2017 encounter was the closest the asteroid will come to Earth until 2093. Image via Wikipedia.
Geminid’s parent – 3200 Phaethon – is a “rock comet” Every year, in December, our planet Earth crosses the orbital path of an object called 3200 Phaethon, a mysterious body that is sometimes referred to as a rock comet. The debris shed by 3200 Phaethon crashes into Earth’s upper atmosphere at some 80,000 miles (130,000 km) per hour, to vaporize as colorful Geminid meteors.
In periods of 1.43 years, this small 5-kilometer (3-mile) wide asteroid-type object swings extremely close to the sun (to within one-third of Mercury’s distance), at which juncture intense thermal fracturing causes it to shed yet more rubble into its orbital stream.
In 2017, 3200 Phaethon was exceedingly nearby around nights of the Geminid meteor shower’s peak. This object swept to within 0.069 astronomical units (6.4 million miles, 10.3 million km, 26 lunar-distances) on December 16, 2017. Click here to know 3200 Phaethon’s present distance from the Earth and sun.
Meteor flying straight from Gemini’s two brightest stars, Castor and Pollux, during the 2012 Geminid meteor shower. Photo by EarthSky Facebook friend Mike O’Neal in Oklahoma.
Bottom line: Meteor showers are part of nature and so inherently unpredictable. But the reliable Geminid shower counts as one of the year’s best, peppering the nighttime sky with 50 or more meteors per hour at its peak.
from EarthSky https://ift.tt/2FXXFE5
Wesley Loftis in Clarksville, Virginia, caught this Geminid meteor during the 2017 shower.
The Geminid meteor shower – always a highlight of the meteor year – will peak around the mornings of December 13 and 14, 2018. The Geminids are a very reliable shower if you watch at the peak time of night (centered on about 2 a.m. for all parts of the globe) and if you watch in a dark sky. The meteors tend to be bold, white and quick! This shower favors Earth’s Northern Hemisphere, but it’s visible from the Southern Hemisphere, too. The curious rock comet called 3200 Phaethon is the parent body of this shower.
On a dark night, near the peak, you can often catch 50 or more meteors per hour.
Why are the Geminids best around 2 a.m.? It’s because that’s when the shower’s radiant point – the point in our sky from which the meteors seem to radiate – is highest in the sky. As a general rule, the higher the constellation Gemini the Twins climbs into your sky, the more Geminid meteors you’re likely to see. The Geminids’ radiant point is highest around 2 a.m.
Special equipment? None needed. Just find a dark, open sky and maybe bring a sleeping bag to keep warm. Plan to sprawl back in a hammock, lawn chair, pile of hay or blanket on the ground.
Martin Marthadinata in Surabaya, East Java, Indonesia, caught this Geminid fireball in 2014, coming from the shower’s radiant point near the star Castor.
The Geminids radiate from near the bright star Castor in the constellation Gemini, in the east on December evenings, highest around 2 a.m. Learn more about the Geminids’ radiant point.
This Geminids’ radiant point nearly coincides with the bright star Castor in Gemini. That’s a chance alignment, of course, as Castor lies about 52 light-years away while these meteors burn up in the upper atmosphere, some 60 miles (100 km) above Earth’s surface.
Castor is noticeably near another bright star, the golden star Pollux of Gemini. It’s fun to spot them, but you don’t need to find a meteor shower’s radiant point in order see the meteors.
Instead, meteors in annual showers appear in all parts of the sky. It’s even possible to have your back to the constellation Gemini and see a Geminid meteor fly by.
That’s why, when you’re meteor-watching, it’s good to bring along a buddy. Then two of you can watch in different directions. When someone sees one, they can call out “meteor!” This technique will let you see more meteors than one person watching alone will see.
Be sure to give yourself at least an hour of observing time. It takes about 20 minutes for your eyes to adapt to the dark.
Be aware that meteors often come in spurts, interspersed with lulls.
Painting of 1860 earthgrazer fireball by Frederic Edwin Church. Image via Wikimedia Commons.
Earthgrazers possible possible at early evening. Okay, we said you’ll likely see the most meteors at a time of night centered around 2 a.m. You won’t see as many Geminid meteors in early evening, when the constellation Gemini sits close to the eastern horizon.
But the evening hours are the best time to try to catch an earthgrazer meteor.
An earthgrazer is a slow-moving, long-lasting meteor that travels horizontally across the sky.
Earthgrazers are rarely seen but prove to be especially memorable, if you should be lucky enough to catch one.
Radar images of near-Earth asteroid 3200 Phaethon generated by astronomers at the Arecibo Observatory on December 17, 2017. The 2017 encounter was the closest the asteroid will come to Earth until 2093. Image via Wikipedia.
Geminid’s parent – 3200 Phaethon – is a “rock comet” Every year, in December, our planet Earth crosses the orbital path of an object called 3200 Phaethon, a mysterious body that is sometimes referred to as a rock comet. The debris shed by 3200 Phaethon crashes into Earth’s upper atmosphere at some 80,000 miles (130,000 km) per hour, to vaporize as colorful Geminid meteors.
In periods of 1.43 years, this small 5-kilometer (3-mile) wide asteroid-type object swings extremely close to the sun (to within one-third of Mercury’s distance), at which juncture intense thermal fracturing causes it to shed yet more rubble into its orbital stream.
In 2017, 3200 Phaethon was exceedingly nearby around nights of the Geminid meteor shower’s peak. This object swept to within 0.069 astronomical units (6.4 million miles, 10.3 million km, 26 lunar-distances) on December 16, 2017. Click here to know 3200 Phaethon’s present distance from the Earth and sun.
Meteor flying straight from Gemini’s two brightest stars, Castor and Pollux, during the 2012 Geminid meteor shower. Photo by EarthSky Facebook friend Mike O’Neal in Oklahoma.
Bottom line: Meteor showers are part of nature and so inherently unpredictable. But the reliable Geminid shower counts as one of the year’s best, peppering the nighttime sky with 50 or more meteors per hour at its peak.
