New closest-known black hole lies in a visible star system

Artist’s concept of a black hole via ESO.

Originally published on May 6, 2020, by the European Southern Observatory.

A team of astronomers from the European Southern Observatory (ESO) and other institutes has discovered a black hole lying just 1,000 light-years from Earth. The black hole is closer to our solar system than any other found to date and forms part of a triple system that can be seen with the unaided eye. The team found evidence for the invisible object by tracking its two companion stars using the 2.2-meter telescope at ESO’s La Silla Observatory in Chile. They say this system could just be the tip of the iceberg, as many more similar black holes could be found in the future.

Prior to this discovery, the closest-known black hole was A0620-00 in the constellation of Monoceros at a distance of 3,000 light years.

Petr Hadrava of the Academy of Sciences of the Czech Republic in Prague, a co-author of the research, said:

We were totally surprised when we realized that this is the first stellar system with a black hole that can be seen with the unaided eye.

Located in the constellation of Telescopium, the system is so close to us that its stars can be viewed from the Southern Hemisphere on a dark, clear night without binoculars or a telescope.

ESO scientist Thomas Rivinius, who led the study published May 6, 2020, in Astronomy & Astrophysics (doi: 10.1051/0004-6361/202038020), said:

This system contains the nearest black hole to Earth that we know of.

This chart shows the location of the HR 6819 triple system, which includes the closest black hole to Earth, in the constellation of Telescopium. This map shows most of the stars visible to the unaided eye under good conditions and the system itself is marked with a red circle. While the black hole is invisible, the two stars in HR 6819 can be viewed from the Southern Hemisphere on a dark, clear night without binoculars or a telescope. Image via ESO/ IAU/ Sky & Telescope.

The team originally observed the system, called HR 6819, as part of a study of double-star systems. However, as they analyzed their observations, they were stunned when they revealed a third, previously undiscovered body in HR 6819: a black hole. The observations with the FEROS spectrograph on the 2.2-meter telescope at La Silla showed that one of the two visible stars orbits an unseen object every 40 days, while the second star is at a large distance from this inner pair.

Dietrich Baade of ESO in Garching and co-author of the study, said:

The observations needed to determine the period of 40 days had to be spread over several months …

The hidden black hole in HR 6819 is one of the very first stellar-mass black holes found that do not interact violently with their environment and, therefore, appear truly black. But the team could spot its presence and calculate its mass by studying the orbit of the star in the inner pair. Rivinius, who is based in Chile, commented:

An invisible object with a mass at least 4 times that of the sun can only be a black hole.

Astronomers have spotted only a couple of dozen black holes in our galaxy to date, nearly all of which strongly interact with their environment and make their presence known by releasing powerful X-rays in this interaction. But scientists estimate that, over the Milky Way’s lifetime, many more stars collapsed into black holes as they ended their lives. The discovery of a silent, invisible black hole in HR 6819 provides clues about where the many hidden black holes in the Milky Way might be. Rivinius explained:

There must be hundreds of millions of black holes out there, but we know about only very few. Knowing what to look for should put us in a better position to find them.

Baade added that finding a black hole in a triple system so close by indicates that we are seeing just “the tip of an exciting iceberg.”

Already, astronomers believe their discovery could shine some light on a second system. Marianne Heida, a postdoctoral fellow at ESO and co-author of the paper, said:

We realized that another system, called LB-1, may also be such a triple, though we’d need more observations to say for sure. LB-1 is a bit further away from Earth but still pretty close in astronomical terms, so that means that probably many more of these systems exist. By finding and studying them we can learn a lot about the formation and evolution of those rare stars that begin their lives with more than about 8 times the mass of the sun and end them in a supernova explosion that leaves behind a black hole.

The discoveries of these triple systems with an inner pair and a distant star could also provide clues about the violent cosmic mergers that release gravitational waves powerful enough to be detected on Earth. Some astronomers believe that the mergers can happen in systems with a similar configuration to HR 6819 or LB-1, but where the inner pair is made up of two black holes or of a black hole and a neutron star. The distant outer object can gravitationally impact the inner pair in such a way that it triggers a merger and the release of gravitational waves. Although HR 6819 and LB-1 have only one black hole and no neutron stars, these systems could help scientists understand how stellar collisions can happen in triple star systems.

Bottom line: An invisible object has 2 companion stars in the triple star system HR 6819. The 2 companion stars can be seen with the unaided eye. The invisible object can only be a black hole, these astronomers said. It’s located only 1, 000 light-years from Earth, closer than any other black hole found so far.

Source: A naked-eye triple system with a nonaccreting black hole in the inner binary

Via ESO

from EarthSky https://ift.tt/2Lb6QR7

Artist’s concept of a black hole via ESO.

Originally published on May 6, 2020, by the European Southern Observatory.

A team of astronomers from the European Southern Observatory (ESO) and other institutes has discovered a black hole lying just 1,000 light-years from Earth. The black hole is closer to our solar system than any other found to date and forms part of a triple system that can be seen with the unaided eye. The team found evidence for the invisible object by tracking its two companion stars using the 2.2-meter telescope at ESO’s La Silla Observatory in Chile. They say this system could just be the tip of the iceberg, as many more similar black holes could be found in the future.

Prior to this discovery, the closest-known black hole was A0620-00 in the constellation of Monoceros at a distance of 3,000 light years.

Petr Hadrava of the Academy of Sciences of the Czech Republic in Prague, a co-author of the research, said:

We were totally surprised when we realized that this is the first stellar system with a black hole that can be seen with the unaided eye.

Located in the constellation of Telescopium, the system is so close to us that its stars can be viewed from the Southern Hemisphere on a dark, clear night without binoculars or a telescope.

ESO scientist Thomas Rivinius, who led the study published May 6, 2020, in Astronomy & Astrophysics (doi: 10.1051/0004-6361/202038020), said:

This system contains the nearest black hole to Earth that we know of.

This chart shows the location of the HR 6819 triple system, which includes the closest black hole to Earth, in the constellation of Telescopium. This map shows most of the stars visible to the unaided eye under good conditions and the system itself is marked with a red circle. While the black hole is invisible, the two stars in HR 6819 can be viewed from the Southern Hemisphere on a dark, clear night without binoculars or a telescope. Image via ESO/ IAU/ Sky & Telescope.

The team originally observed the system, called HR 6819, as part of a study of double-star systems. However, as they analyzed their observations, they were stunned when they revealed a third, previously undiscovered body in HR 6819: a black hole. The observations with the FEROS spectrograph on the 2.2-meter telescope at La Silla showed that one of the two visible stars orbits an unseen object every 40 days, while the second star is at a large distance from this inner pair.

Dietrich Baade of ESO in Garching and co-author of the study, said:

The observations needed to determine the period of 40 days had to be spread over several months …

The hidden black hole in HR 6819 is one of the very first stellar-mass black holes found that do not interact violently with their environment and, therefore, appear truly black. But the team could spot its presence and calculate its mass by studying the orbit of the star in the inner pair. Rivinius, who is based in Chile, commented:

An invisible object with a mass at least 4 times that of the sun can only be a black hole.

Astronomers have spotted only a couple of dozen black holes in our galaxy to date, nearly all of which strongly interact with their environment and make their presence known by releasing powerful X-rays in this interaction. But scientists estimate that, over the Milky Way’s lifetime, many more stars collapsed into black holes as they ended their lives. The discovery of a silent, invisible black hole in HR 6819 provides clues about where the many hidden black holes in the Milky Way might be. Rivinius explained:

There must be hundreds of millions of black holes out there, but we know about only very few. Knowing what to look for should put us in a better position to find them.

Baade added that finding a black hole in a triple system so close by indicates that we are seeing just “the tip of an exciting iceberg.”

Already, astronomers believe their discovery could shine some light on a second system. Marianne Heida, a postdoctoral fellow at ESO and co-author of the paper, said:

We realized that another system, called LB-1, may also be such a triple, though we’d need more observations to say for sure. LB-1 is a bit further away from Earth but still pretty close in astronomical terms, so that means that probably many more of these systems exist. By finding and studying them we can learn a lot about the formation and evolution of those rare stars that begin their lives with more than about 8 times the mass of the sun and end them in a supernova explosion that leaves behind a black hole.

The discoveries of these triple systems with an inner pair and a distant star could also provide clues about the violent cosmic mergers that release gravitational waves powerful enough to be detected on Earth. Some astronomers believe that the mergers can happen in systems with a similar configuration to HR 6819 or LB-1, but where the inner pair is made up of two black holes or of a black hole and a neutron star. The distant outer object can gravitationally impact the inner pair in such a way that it triggers a merger and the release of gravitational waves. Although HR 6819 and LB-1 have only one black hole and no neutron stars, these systems could help scientists understand how stellar collisions can happen in triple star systems.

Bottom line: An invisible object has 2 companion stars in the triple star system HR 6819. The 2 companion stars can be seen with the unaided eye. The invisible object can only be a black hole, these astronomers said. It’s located only 1, 000 light-years from Earth, closer than any other black hole found so far.

Source: A naked-eye triple system with a nonaccreting black hole in the inner binary

Via ESO

from EarthSky https://ift.tt/2Lb6QR7

Last full supermoon of 2020

Above: Stefano Sciarpetti created this composite image of a full supermoon (full moon closest to Earth) with a micro-moon (full moon farthest from Earth). It was the Astronomy Picture of the Day for January 21, 2014.

On both May 6 and 7, 2020, the moon will appear round and full to the eye as it lights up the night from dusk until dawn. This May full moon is 2020’s third and final full supermoon, and it’s also the third-closest, third-biggest and third-brightest supermoon of 2020. The first supermoon of 2020 was on March 9. The second was on the night of April 7-8; it was April when the full moon and lunar perigee (the moon’s closest point to Earth in its monthly orbit) aligned most closely for the year 2020, giving us the biggest and brightest full supermoon of the year.

This May 2020 supermoon isn’t the biggest or brightest, but it is, by definition, a supermoon: a full moon or new moon within 90% of its closest approach to Earth. That definition isn’t official in any sense, but it’s become engrained in popular culture.

In North America – according to the popular culture of earlier times, what we now call folklore, or skylore – we’ll also call this May 2020 supermoon by the names the Flower Moon, Planting Moon or Milk Moon. It’ll shine in front of the constellation Libra the Scales.

Moon’s present position in front of the constellations of the zodiac via Heavens-Above

Full moon supermoons in 2020:

March 9, 2000: 222,081 miles (357,404 km)

April 8, 2020: 221,851 miles (357,035 km)

May 7, 2020: 224,429 miles (361,184 km)

This month, the moon turns precisely full on May 7, at 10:45 UTC. Although the full moon happens at the same instant worldwide, the clock reads differently by time zone. At North American and United States time zones, the moon reaches the crest of its full phase on May 7, at 7:45 a.m. ADT, 6:45 a.m. EDT, 5:45 a.m. CDT, 4:45 a.m. MDT, 3:45 a.m. PDT, 2:45 a.m. AKDT and 12:45 a.m. HST.

The moon always appears full to the eye for two to three days in a row. Twelve hours before and after this May full moon, the moon is still 99.6% illuminated by sunshine (according to The Moon Tonight).

Meanwhile, astronomers regard the moon as full at the instant that it’s exactly 180 degrees opposite the sun in ecliptic longitude. In other words, the moon-sun elongation at full moon equals 180 degrees. Click on The Moon Tonight to find out the present moon-sun elongation, remembering that a positive number refers to a waxing (increasing) moon and a negative number to a waning (shrinking) moon.

From one month to the next – unless you’re a very experienced observer – you’re not likely to discern a size difference between full moons.

On the other hand, full supermoons might be noticeably brighter. A full moon at perigee (closest point to Earth in the moon’s monthly orbit) is about 15 percent brighter than a full moon at its average distance from Earth, and about 30 percent brighter than a full moon at apogee (farthest point from Earth in the moon’s monthly orbit). This May 2020 supermoon, though … it’ll be a bit brighter than non-supermoons, but perhaps not noticeably so.

So it’ll be a fairly ordinary-looking moon that ascends in your sky around sunset on May 6 and 7, 2020 and that shines brightly in your sky all night on these nights. And indeed some skywatchers object to the term supermoon, because the size differences of full moons aren’t readily discernible to the eye. That’s true. They aren’t. On the other hand, few – if any – sky gazers can tell the exact moment of a 100-percent-illuminated full moon with the eye, either. And yet astronomical almanacs give the full moon times to the minute. A photo finish to determine the winner of a contest doesn’t make the event any less exciting.

Here’s a comparison between the December 3, 2017, full moon at perigee (closest to Earth for the month) and the year’s farthest full moon in June 2017 at apogee (farthest from Earth for the month) by Muzamir Mazlan at Telok Kemang Observatory, Port Dickson, Malaysia. More photos of the December 2017 supermoon.

The full moon’s distance only changes incrementally from month to month, as we show on the listing below. For instance, a full moon that aligns with lunar apogee (the moon’s most distant point in its orbit) never precedes or follows a full moon aligning with perigee. In fact, the smallest full moon of the year on October 31, 2020, comes exactly 7 lunar months (7 full moons) after the year’s biggest full moon on April 8, 2020:

Full moon distances:

April 8, 2020: 221,851 miles (357,035 km)

May 7, 2020: 224,429 miles (361,184 km)

June 5, 2020: 229,285 miles (368,999 km)

July 5, 2020: 235,586 miles (379,140 km)

August 3, 2020: 242,254 miles (389,871 km)

September 2, 2020: 248,051 miles (399,200 km)

October 1, 2020: 251,747 miles (405,147 km)

October 31, 2020: 252,380 miles (406,166 km)

Source: The Moon Tonight

And guess what? Exactly 7 lunar months (7 full moons) after the year’s farthest and smallest full moon on October 31, 2020, it’ll be next year’s closest and largest full moon on May 26, 2021! Moreover, this May 2021 full moon will pass right through the Earth’s dark umbral shadow, to stage the first total lunar eclipse since January 21, 2019.

Here’s something fun to think about. Illustration via Phil Plait. Phil explains: “The guy at the top of the Earth in the diagram sees the moon on his horizon, and the guy on the side of the Earth sees it overhead. But you can tell the distances aren’t the same: the moon is closer to the guy who sees it as overhead (by an amount roughly equal to the Earth’s radius).” Cool!

Bottom line: Enjoy the last full moon supermoon of the year on May 6 and 7, 2020. The moon turns precisely full on May 7 at 10:45 UTC; translate UTC to your time.

Read more: What is a supermoon?

from EarthSky https://ift.tt/2L13r7H

Above: Stefano Sciarpetti created this composite image of a full supermoon (full moon closest to Earth) with a micro-moon (full moon farthest from Earth). It was the Astronomy Picture of the Day for January 21, 2014.

On both May 6 and 7, 2020, the moon will appear round and full to the eye as it lights up the night from dusk until dawn. This May full moon is 2020’s third and final full supermoon, and it’s also the third-closest, third-biggest and third-brightest supermoon of 2020. The first supermoon of 2020 was on March 9. The second was on the night of April 7-8; it was April when the full moon and lunar perigee (the moon’s closest point to Earth in its monthly orbit) aligned most closely for the year 2020, giving us the biggest and brightest full supermoon of the year.

This May 2020 supermoon isn’t the biggest or brightest, but it is, by definition, a supermoon: a full moon or new moon within 90% of its closest approach to Earth. That definition isn’t official in any sense, but it’s become engrained in popular culture.

In North America – according to the popular culture of earlier times, what we now call folklore, or skylore – we’ll also call this May 2020 supermoon by the names the Flower Moon, Planting Moon or Milk Moon. It’ll shine in front of the constellation Libra the Scales.

Moon’s present position in front of the constellations of the zodiac via Heavens-Above

Full moon supermoons in 2020:

March 9, 2000: 222,081 miles (357,404 km)

April 8, 2020: 221,851 miles (357,035 km)

May 7, 2020: 224,429 miles (361,184 km)

This month, the moon turns precisely full on May 7, at 10:45 UTC. Although the full moon happens at the same instant worldwide, the clock reads differently by time zone. At North American and United States time zones, the moon reaches the crest of its full phase on May 7, at 7:45 a.m. ADT, 6:45 a.m. EDT, 5:45 a.m. CDT, 4:45 a.m. MDT, 3:45 a.m. PDT, 2:45 a.m. AKDT and 12:45 a.m. HST.

The moon always appears full to the eye for two to three days in a row. Twelve hours before and after this May full moon, the moon is still 99.6% illuminated by sunshine (according to The Moon Tonight).

Meanwhile, astronomers regard the moon as full at the instant that it’s exactly 180 degrees opposite the sun in ecliptic longitude. In other words, the moon-sun elongation at full moon equals 180 degrees. Click on The Moon Tonight to find out the present moon-sun elongation, remembering that a positive number refers to a waxing (increasing) moon and a negative number to a waning (shrinking) moon.

From one month to the next – unless you’re a very experienced observer – you’re not likely to discern a size difference between full moons.

On the other hand, full supermoons might be noticeably brighter. A full moon at perigee (closest point to Earth in the moon’s monthly orbit) is about 15 percent brighter than a full moon at its average distance from Earth, and about 30 percent brighter than a full moon at apogee (farthest point from Earth in the moon’s monthly orbit). This May 2020 supermoon, though … it’ll be a bit brighter than non-supermoons, but perhaps not noticeably so.

So it’ll be a fairly ordinary-looking moon that ascends in your sky around sunset on May 6 and 7, 2020 and that shines brightly in your sky all night on these nights. And indeed some skywatchers object to the term supermoon, because the size differences of full moons aren’t readily discernible to the eye. That’s true. They aren’t. On the other hand, few – if any – sky gazers can tell the exact moment of a 100-percent-illuminated full moon with the eye, either. And yet astronomical almanacs give the full moon times to the minute. A photo finish to determine the winner of a contest doesn’t make the event any less exciting.

Here’s a comparison between the December 3, 2017, full moon at perigee (closest to Earth for the month) and the year’s farthest full moon in June 2017 at apogee (farthest from Earth for the month) by Muzamir Mazlan at Telok Kemang Observatory, Port Dickson, Malaysia. More photos of the December 2017 supermoon.

The full moon’s distance only changes incrementally from month to month, as we show on the listing below. For instance, a full moon that aligns with lunar apogee (the moon’s most distant point in its orbit) never precedes or follows a full moon aligning with perigee. In fact, the smallest full moon of the year on October 31, 2020, comes exactly 7 lunar months (7 full moons) after the year’s biggest full moon on April 8, 2020:

Full moon distances:

April 8, 2020: 221,851 miles (357,035 km)

May 7, 2020: 224,429 miles (361,184 km)

June 5, 2020: 229,285 miles (368,999 km)

July 5, 2020: 235,586 miles (379,140 km)

August 3, 2020: 242,254 miles (389,871 km)

September 2, 2020: 248,051 miles (399,200 km)

October 1, 2020: 251,747 miles (405,147 km)

October 31, 2020: 252,380 miles (406,166 km)

Source: The Moon Tonight

And guess what? Exactly 7 lunar months (7 full moons) after the year’s farthest and smallest full moon on October 31, 2020, it’ll be next year’s closest and largest full moon on May 26, 2021! Moreover, this May 2021 full moon will pass right through the Earth’s dark umbral shadow, to stage the first total lunar eclipse since January 21, 2019.

Here’s something fun to think about. Illustration via Phil Plait. Phil explains: “The guy at the top of the Earth in the diagram sees the moon on his horizon, and the guy on the side of the Earth sees it overhead. But you can tell the distances aren’t the same: the moon is closer to the guy who sees it as overhead (by an amount roughly equal to the Earth’s radius).” Cool!

Bottom line: Enjoy the last full moon supermoon of the year on May 6 and 7, 2020. The moon turns precisely full on May 7 at 10:45 UTC; translate UTC to your time.

Read more: What is a supermoon?

from EarthSky https://ift.tt/2L13r7H

Global experts call for mental health science to combat pandemic's impacts

Emory anthropologist Carol Worthman is among 25 mental health experts who issued a call for global action on mental health science surrounding the COVID-19 pandemic.

By Carol Clark

The outbreak of severe acute respiratory syndrome (SARS) in 2003 infected about 8,000 people and killed hundreds. Although SARS was stamped out relatively quickly, and before it could spread globally, it left a lingering impact. One study found that most SARS survivors in two major hospitals had high levels of psychological distress a year after the outbreak.

“Just surviving the pandemic was not the end of the story,” says Carol Worthman, professor of anthropology at Emory University. “And the COVID-19 pandemic is much more pervasive than SARS. It affects everybody, worldwide. Even those who do not get COVID-19 will have to live with the fallout.”

Worthman is among 25 mental health experts who issued a call for global action on mental health science surrounding the COVID-19 pandemic, recently published by The Lancet Psychiatry. In a position paper, they stress the immediate need for creating neuro-psychological databases concerning the pandemic’s impacts on brain health, mental health and overall well-being. These databases are needed to support evidence-based responses to the pandemic and to develop longer-term strategies to promote mental health and well-being.

Even as nations mobilize to treat patients, develop drugs and vaccines, and salvage economies, coordinated efforts on a similar scale are needed for mental health, Worthman says. Her research focuses on how cultural and social factors interact with human health, for better or for worse.

“We’re used to thinking about physical diseases and mental illnesses as two separate things,” Worthman says, “but the two actually go hand-in-hand. Mental illness doesn’t just affect the lives of individuals, but of those around them. And like a virus, mental illness is invisible, in a way, and can be even harder to test and screen for.” Before the pandemic, depression already ranked in the top 10 causes of poor health worldwide and had climbed to the top four health problems related to healthy years of life lost.

The impacts of the lockdowns and social isolation on the mental health of vulnerable people are among the key questions that need to be tackled in an international response to COVID-19, the experts write. Their paper also stresses the need to research the best ways to move people to follow the advice of public health messages without unduly increasing stress and anxiety.

“People are especially hurting right now, they’re suffering, and they’re looking for ways to feel better,” Worthman says. “If we don’t develop pro-social ways to help people cope now and, in the future, we’re going to be living with the consequences for a long time.”

She points out that the 1918 flu pandemic, following on top of the first world war, helped set the stage for the social disruption and sense of hopelessness that fueled political movements and nationalism leading to the second world war.

One critical need is to gather data and develop strategies to support people currently working in high-intensity, high-risk settings during the pandemic, such as healthcare workers. “Burnout and higher suicide rates among healthcare providers had already been a growing problem for years,” Worthman says.

She cites the mental health effects of massive unemployment as another critical area. “Work is a huge part of peoples’ identities, not to mention their livelihoods,” she says. “Depression, anxiety, stress and lack of control are all things that undermine resilience. What can we do to help people stay resilient when they’re losing their sense of dignity and self-worth and predictability for their futures?”

Youth and adolescent mental health is another vital area to consider, Worthman says. “Young people are having to watch a remapping of the social-economic political world and try to find their way through it. Their future is our future and they need to be part of the solution. How do we mobilize youth to help them make their future as great as possible? Do we make supporting youth as important as saving airlines and other industries?”

COVID-19 is revealing and widening existing fault lines in social, economic and political systems. “We now have the challenge and opportunity to heal those ruptures even as we seek to heal ourselves of COVID-19,” Worthman says.

Related:
The importance of puberty: A call for better research models
How family stories help children weather hard times



from eScienceCommons https://ift.tt/3fmFTYB

Emory anthropologist Carol Worthman is among 25 mental health experts who issued a call for global action on mental health science surrounding the COVID-19 pandemic.

By Carol Clark

The outbreak of severe acute respiratory syndrome (SARS) in 2003 infected about 8,000 people and killed hundreds. Although SARS was stamped out relatively quickly, and before it could spread globally, it left a lingering impact. One study found that most SARS survivors in two major hospitals had high levels of psychological distress a year after the outbreak.

“Just surviving the pandemic was not the end of the story,” says Carol Worthman, professor of anthropology at Emory University. “And the COVID-19 pandemic is much more pervasive than SARS. It affects everybody, worldwide. Even those who do not get COVID-19 will have to live with the fallout.”

Worthman is among 25 mental health experts who issued a call for global action on mental health science surrounding the COVID-19 pandemic, recently published by The Lancet Psychiatry. In a position paper, they stress the immediate need for creating neuro-psychological databases concerning the pandemic’s impacts on brain health, mental health and overall well-being. These databases are needed to support evidence-based responses to the pandemic and to develop longer-term strategies to promote mental health and well-being.

Even as nations mobilize to treat patients, develop drugs and vaccines, and salvage economies, coordinated efforts on a similar scale are needed for mental health, Worthman says. Her research focuses on how cultural and social factors interact with human health, for better or for worse.

“We’re used to thinking about physical diseases and mental illnesses as two separate things,” Worthman says, “but the two actually go hand-in-hand. Mental illness doesn’t just affect the lives of individuals, but of those around them. And like a virus, mental illness is invisible, in a way, and can be even harder to test and screen for.” Before the pandemic, depression already ranked in the top 10 causes of poor health worldwide and had climbed to the top four health problems related to healthy years of life lost.

The impacts of the lockdowns and social isolation on the mental health of vulnerable people are among the key questions that need to be tackled in an international response to COVID-19, the experts write. Their paper also stresses the need to research the best ways to move people to follow the advice of public health messages without unduly increasing stress and anxiety.

“People are especially hurting right now, they’re suffering, and they’re looking for ways to feel better,” Worthman says. “If we don’t develop pro-social ways to help people cope now and, in the future, we’re going to be living with the consequences for a long time.”

She points out that the 1918 flu pandemic, following on top of the first world war, helped set the stage for the social disruption and sense of hopelessness that fueled political movements and nationalism leading to the second world war.

One critical need is to gather data and develop strategies to support people currently working in high-intensity, high-risk settings during the pandemic, such as healthcare workers. “Burnout and higher suicide rates among healthcare providers had already been a growing problem for years,” Worthman says.

She cites the mental health effects of massive unemployment as another critical area. “Work is a huge part of peoples’ identities, not to mention their livelihoods,” she says. “Depression, anxiety, stress and lack of control are all things that undermine resilience. What can we do to help people stay resilient when they’re losing their sense of dignity and self-worth and predictability for their futures?”

Youth and adolescent mental health is another vital area to consider, Worthman says. “Young people are having to watch a remapping of the social-economic political world and try to find their way through it. Their future is our future and they need to be part of the solution. How do we mobilize youth to help them make their future as great as possible? Do we make supporting youth as important as saving airlines and other industries?”

COVID-19 is revealing and widening existing fault lines in social, economic and political systems. “We now have the challenge and opportunity to heal those ruptures even as we seek to heal ourselves of COVID-19,” Worthman says.

Related:
The importance of puberty: A call for better research models
How family stories help children weather hard times



from eScienceCommons https://ift.tt/3fmFTYB

COVID-19: The Cancer Research UK scientists manufacturing PPE

COVID-19 is delaying cancer research and treatment. We catch up with some of the cancer researchers who are using their expertise, experience and equipment to help tackle COVID-19 and get cancer services back on track.

The shortage of personal protective equipment (PPE) for NHS workers has been a headline issue in the UK.  

Standard PPE kit includes an apron, gloves, a surgical mask and eye protection, which is vital to the safety of those working at the front line of the coronavirus crisis and they people they’re looking after. Without it, they’re at a higher risk of catching COVID-19.

Alongside widespread COVID-19 testing, PPE is essential to protect healthcare workers and ensure cancer care can continue during the pandemic.

It’s in exceptional times like these that people across the country have been motivated to respond, doing everything from sewing scrubs and facemasks at home to donate to the NHS to volunteering to deliver medicines or food to people at risk.

We spoke to two of our scientists who are doing their bit to help COVID-19 efforts – using their expertise in 3D printing to help provide essential PPE to health workers around the country.  

Steve Bagley, Manchester: ‘I wondered how I could help’ 

The 3D printer at the Manchester Institute is being used by Steve Bagley to produce essential PPE.

Steve Bagley is a cancer scientist from our Manchester Institute. He normally works with microscopes and X-ray machinery to analyse cancer cells, but became increasingly aware of the lack of PPE for our frontline staff. “I saw that there was a need for more protective equipment for those working in the NHS, so I wondered how I could help.”   

Bagley has produced over 200 head straps.

While the Institute’s labs at Alderley Park have been temporarily closed for research, Bagley has been tasked with the job of looking after and maintaining the specialist lab equipment, including a 3D printer.  

“I’m very familiar with the 3D printer, as it’s a piece of kit we use regularly to create parts for microscopes and other lab equipment,” says Bagley. “And it occurred to me that I could use this to create plastic headbands for protective face masks.” 

Once Bagley had worked out a template, with correct dimensions for the headbands, he began a mini production line, printing the plastic headbands in the lab.  

So far, Bagley has produced over 200 protective face masks for frontline healthcare staff. The PPE will be distributed to hospitals across the North West, including The Christie NHS Foundation Trust in Manchester. 

“I really wanted to do something to support all those who are working so hard on the frontline in the battle against Covid-19. And the sooner we beat this virus, the sooner we can return to beating cancer.” 

Marcel Gehrung, Cambridge: ‘It was like a domino of requests for PPE’ 

Some of the protective visors manufactured by Marcel Gehrung.

“There is this very public discussion about the lack of personal protective equipment for different health care professionals in the NHS,” says Marcel Gehrung, a PhD student at the Cancer Research UK Cambridge Institute, investigating machine learning applications in healthcare, with a focus on medical imaging. Whilst completing his PhD in Cambridge, Gehrung co-founded Cyted, a new diagnostics company that uses artificial intelligence to detect cancers earlier.  

And it was this work that drew him into the discussions around PPE.  

The company has been involved with the commercialisation of the Cytosponge – a ‘sponge-on-a-string’ test that can detect oesophageal cancer earlier. Cytosponge was developed to help pick up Barrett’s oesophagus, a condition that can develop into oesophageal cancer, but plans were adapted in the face of  the COVID-19 outbreak. 

“We were contacted by a lot of trusts saying they don’t have endoscopy capacity anymore, and their waiting lists for people who are being referred for endoscopy are getting very long,” Gehrung explains. To help mitigate this reduction in endoscopies the Cytosponge – the test used to diagnose oesophageal conditions, such as Barrett’s oesophagus and cancer – has been piloted in Addenbrooke’s hospital as an emergency response. 

His involvement in rolling out the Cytosponge test has given him a real insight into the needs of healthcare workers. 

Gehrung and his team were asked about sourcing protective equipment by the nurses running the Cytosponge testing facility at Addenbrooke’s hospital in Cambridge. The Cytosponge test requires nurses to retrieve the device from the patient’s stomach, which sometimes involves coughing as it passes the throat, “so it is very important for the healthcare staff to have face shields”.  

After a couple of days of thinking about where they could source face masks, Gehrung took matters into his own hands. “I started talking to our Institute Director and Director of Operations and said that we could actually use the Institute’s printers to make more visors.” 

Gehrung transported the equipment, which wasn’t being used at the time, from the Institute to his home in Cambridge, and is now producing visors using multiple 3D printers in his living room.  

“So far we just have produced them on demand,” says Gehrung, “we had this domino reaction happening where people would say ‘oh yeah I need another two and I have a few colleagues who are trying to source them as well’”.   

Although it’s hard to say exactly, Gehrung estimates he’s made between 150–250 protective visors.  

Gehrung notes the importance of thinking beyond the area you’re working in to find solutions to tricky situations. “If someone talks about academia and science, they tell you it’s about vertical depth, and having maximum understanding of a topic, but breadth is very helpful for this situation, as it helps you think outside of the box.” 

Lilly

Read more:

• Marcel Gehrung- the many hats of an entrepreneur at home

from Cancer Research UK – Science blog https://ift.tt/2YDDh2K

COVID-19 is delaying cancer research and treatment. We catch up with some of the cancer researchers who are using their expertise, experience and equipment to help tackle COVID-19 and get cancer services back on track.

The shortage of personal protective equipment (PPE) for NHS workers has been a headline issue in the UK.  

Standard PPE kit includes an apron, gloves, a surgical mask and eye protection, which is vital to the safety of those working at the front line of the coronavirus crisis and they people they’re looking after. Without it, they’re at a higher risk of catching COVID-19.

Alongside widespread COVID-19 testing, PPE is essential to protect healthcare workers and ensure cancer care can continue during the pandemic.

It’s in exceptional times like these that people across the country have been motivated to respond, doing everything from sewing scrubs and facemasks at home to donate to the NHS to volunteering to deliver medicines or food to people at risk.

We spoke to two of our scientists who are doing their bit to help COVID-19 efforts – using their expertise in 3D printing to help provide essential PPE to health workers around the country.  

Steve Bagley, Manchester: ‘I wondered how I could help’ 

The 3D printer at the Manchester Institute is being used by Steve Bagley to produce essential PPE.

Steve Bagley is a cancer scientist from our Manchester Institute. He normally works with microscopes and X-ray machinery to analyse cancer cells, but became increasingly aware of the lack of PPE for our frontline staff. “I saw that there was a need for more protective equipment for those working in the NHS, so I wondered how I could help.”   

Bagley has produced over 200 head straps.

While the Institute’s labs at Alderley Park have been temporarily closed for research, Bagley has been tasked with the job of looking after and maintaining the specialist lab equipment, including a 3D printer.  

“I’m very familiar with the 3D printer, as it’s a piece of kit we use regularly to create parts for microscopes and other lab equipment,” says Bagley. “And it occurred to me that I could use this to create plastic headbands for protective face masks.” 

Once Bagley had worked out a template, with correct dimensions for the headbands, he began a mini production line, printing the plastic headbands in the lab.  

So far, Bagley has produced over 200 protective face masks for frontline healthcare staff. The PPE will be distributed to hospitals across the North West, including The Christie NHS Foundation Trust in Manchester. 

“I really wanted to do something to support all those who are working so hard on the frontline in the battle against Covid-19. And the sooner we beat this virus, the sooner we can return to beating cancer.” 

Marcel Gehrung, Cambridge: ‘It was like a domino of requests for PPE’ 

Some of the protective visors manufactured by Marcel Gehrung.

“There is this very public discussion about the lack of personal protective equipment for different health care professionals in the NHS,” says Marcel Gehrung, a PhD student at the Cancer Research UK Cambridge Institute, investigating machine learning applications in healthcare, with a focus on medical imaging. Whilst completing his PhD in Cambridge, Gehrung co-founded Cyted, a new diagnostics company that uses artificial intelligence to detect cancers earlier.  

And it was this work that drew him into the discussions around PPE.  

The company has been involved with the commercialisation of the Cytosponge – a ‘sponge-on-a-string’ test that can detect oesophageal cancer earlier. Cytosponge was developed to help pick up Barrett’s oesophagus, a condition that can develop into oesophageal cancer, but plans were adapted in the face of  the COVID-19 outbreak. 

“We were contacted by a lot of trusts saying they don’t have endoscopy capacity anymore, and their waiting lists for people who are being referred for endoscopy are getting very long,” Gehrung explains. To help mitigate this reduction in endoscopies the Cytosponge – the test used to diagnose oesophageal conditions, such as Barrett’s oesophagus and cancer – has been piloted in Addenbrooke’s hospital as an emergency response. 

His involvement in rolling out the Cytosponge test has given him a real insight into the needs of healthcare workers. 

Gehrung and his team were asked about sourcing protective equipment by the nurses running the Cytosponge testing facility at Addenbrooke’s hospital in Cambridge. The Cytosponge test requires nurses to retrieve the device from the patient’s stomach, which sometimes involves coughing as it passes the throat, “so it is very important for the healthcare staff to have face shields”.  

After a couple of days of thinking about where they could source face masks, Gehrung took matters into his own hands. “I started talking to our Institute Director and Director of Operations and said that we could actually use the Institute’s printers to make more visors.” 

Gehrung transported the equipment, which wasn’t being used at the time, from the Institute to his home in Cambridge, and is now producing visors using multiple 3D printers in his living room.  

“So far we just have produced them on demand,” says Gehrung, “we had this domino reaction happening where people would say ‘oh yeah I need another two and I have a few colleagues who are trying to source them as well’”.   

Although it’s hard to say exactly, Gehrung estimates he’s made between 150–250 protective visors.  

Gehrung notes the importance of thinking beyond the area you’re working in to find solutions to tricky situations. “If someone talks about academia and science, they tell you it’s about vertical depth, and having maximum understanding of a topic, but breadth is very helpful for this situation, as it helps you think outside of the box.” 

Lilly

Read more:

• Marcel Gehrung- the many hats of an entrepreneur at home

from Cancer Research UK – Science blog https://ift.tt/2YDDh2K

What’s a constellation? What’s an asterism?

Sometimes several stars in different constellations join together to form a large asterism. That’s true of the Summer Triangle asterism, which is made of 3 bright stars – Vega, Deneb and Altair – in 3 different constellations. Image via our friend Susan Gies Jensen in Odessa, Washington.

What are constellations and asterisms?

A constellation is a recognized pattern of stars in the night sky. The word is from the Latin constellacio, meaning a set of stars. There are 88 official constellations. Many are very old. They’re a link between us and our ancestors, a projection of human imagination into the cosmos: ancient people looked at the stars and thought they saw mythical beings, beasts and cultural touchstones among the stars. On the other hand, most asterisms are relatively new. Most are small patterns within a constellation, although some are large patterns made of bright stars from several constellations. There’s nothing official about asterisms, but people on all parts of Earth still love them and enjoy them.

Stars in a constellation all lie at different distances from the Earth. For example, the three stars comprising the constellation of Triangulum are between 35 and 127 light-years away. While a constellation may look as if all of its stars are the same distance away, in reality that is only because, as we now know, stars vary in size and brightness, so two stars which appear to be the same brightness in the sky may actually be separated by vast distances. This means that an alien astronomer on a planet a hundred light years from Earth would know very different constellations, because they would see the night sky from a completely different perspective.

The Plough, for example, (also known as the Big Dipper or King Charles’ Wain) is a pattern of seven stars within the constellation of Ursa Major, the Great Bear. It is undoubtedly the most famous asterism in the sky, and not least because of its usefulness as a signpost for other stars and constellations. In the southern hemisphere, five stars comprise the Southern Cross, an asterism within the constellation of Crux. Sometimes, asterisms comprise stars of more than one constellation: for example, the glorious Summer Triangle, so prominent in the northern hemisphere sky between June and September, comprises stars in Cygnus, Lyra and Aquila. In Sagittarius there is the famous “teapot” asterism, inside which lies the location of the centre of our Milky Way galaxy.

There is no hard and fast rule for what constitutes an asterism: usually it’s a group of prominent stars in a simple pattern that are among the first that people recognise when they are learning their way around the sky.

Many constellations are well-known: Orion, Ursa Major, Cassiopeia, Cygnus , the famous star patterns you learn first when bitten by the bug of astronomy. But perhaps the most recognized are those that comprise the star signs of the zodiac: Aries, Libra, Pisces, Virgo and the eight others which had a special significance for astrologers, more than two thousand years ago when the first astrological charts were drawn by the Babylonians (although the history of the zodiac may go back further). The twelve constellations of the zodiac had a special significance because, together, they comprise the path through the heavens that the sun appears to follow during one year.

Of course, we now know that the sun does not follow this path, that it is the Earth which is moving and not the sun. We also know that since the first astrological charts were created, a gradual tilting of the Earth’s axis, causing an effect known as the precession of the equinoxes, means that the sun now appears to pass though a thirteenth constellation of the zodiac: that of Ophiuchus, the serpent-bearer. This has had the knock-on effect of changing the dates when the sun “passes through” each zodiacal constellation, so that, for example, Ophiuchus occupies most of the days in the calendar where the astrological sign of Sagittarius resides, and Aquarius largely occupies the space where Pisces is.  Although this does of course invalidate the dates of the astrological star-signs seen in the horoscopes of tabloid newspapers, as well as the dates of the supposed star sign which people are “born under,” it should be remembered that the astrological zodiac has little resemblance to the actual constellations which the star signs represent: astrology simply divides the 360-degree heavens into twelve equal segments, without regard for how many degrees each constellation actually spans in the sky. This means that an astrological star sign can encompass more than one constellation, and therefore the astrological zodiac should be seen as largely symbolic rather than factual. It has nothing to do with the real universe.

It was the Greeks and Romans who, between them, first recognized and named the constellations of the Northern Hemisphere, listed around the second century A.D., although doubtless prehistoric humans had created their own constellations long before them. Indeed, each human culture has seen its own mythology and creation stories in the stars since time immemorial. Not surprisingly, the Greeks and Romans saw the heroes, heroines and beasts from their mythologies in the sky: Pegasus, Orion, Taurus, Cassiopeia and many others.

The first list of constellations we know of appears in Ptolemy’s second-century Almagest, which was his treatise on the apparent motions and stars and planets, and which established a geocentric view of the universe which was to persist for 1200 years. While the Greeks and Romans bequeathed us the names of the Northern Hemisphere constellations, it was Arabs who were the first to name the individual stars composing each: Islamic scholars were the first to systematically map the skies.  Many of these Arabic star names have survived until today: Aldebaran, Alcor, Altair, Algol. The prefix “Al-” is a sure indication of an Islamic name: it simply means “the.” Hence, for example, Aldebaran is “the follower,” because it appears to follow the Hyades star cluster that makes up the head of the constellation of Taurus the Bull.

Certain constellations have acquired special significance over the millennia because of their appearance marking the onset of seasons, telling ancient peoples when to sow or reap their crops, when to collect food or animal skins. Because of the Earth’s orbit around the sun, different constellations become visible at different times of the year. For example, in the Northern Hemisphere the appearance of Orion in the early morning sky warns of the onset of autumn, that temperatures will shortly start to drop. The rising of the Summer Triangle to prominence in the northern sky is a harbinger of summer. Thus, to ancient cultures constellations were more than just patterns: they marked the passing of the seasons, of the years, of life itself.

The 48 constellations of the Northern Hemisphere, and their boundaries, were formally recognized by the International Astronomical Union in 1928 and the official list published in 1930. The story of the constellations of the Southern Hemisphere, however, is a little more complicated. Many of these were named by Italian, Dutch and Portuguese explorers of the 14th to 16th centuries. So as constellations there are objects and beasts associated with the great seafaring voyages of that epoch: Telescopium, the telescope; Octans, the octant; Dorado, the swordfish; Vela, the ship’s sails; Hydrus, the sea serpent. But explorers and observers often proposed different constellations with conflicting names, often to please their patrons. It was not until the 19th century that the current list of southern constellations was agreed upon and adopted.

From an observer’s perspective, from sunset to dawn the sky appears to revolve around one fixed point in the sky. This location in the heavens is what the Earth’s axis points at and is called the celestial pole. In the Northern Hemisphere, Polaris (the pole star) lies very close to the celestial pole, whereas in the Southern Hemisphere there is no bright star marking the location. Those constellations which revolve around the celestial pole yet do not dip below the horizon during the night, due to their proximity to it, are known as circumpolar constellations. In other words, for an observer these constellations will never set. There are five of these in the Northern Hemisphere: Ursa Major, Ursa Minor, Draco, Cassiopeia and Cepheus. The Southern Hemisphere has three: Crux, Centaurus and Carina.

The constellations are not difficult for a budding astronomer to learn. There are many excellent resources and planetarium-type programs available free online. It is certainly worth learning to recognize the constellations, even if sometimes we strain to see what the ancients did!

Bottom line: Constellations and asterisms are patterns of stars. Some asterisms consist of stars from different constellations, and some asterisms are part of one constellation.

from EarthSky https://ift.tt/2YyXaI6

Sometimes several stars in different constellations join together to form a large asterism. That’s true of the Summer Triangle asterism, which is made of 3 bright stars – Vega, Deneb and Altair – in 3 different constellations. Image via our friend Susan Gies Jensen in Odessa, Washington.

What are constellations and asterisms?

A constellation is a recognized pattern of stars in the night sky. The word is from the Latin constellacio, meaning a set of stars. There are 88 official constellations. Many are very old. They’re a link between us and our ancestors, a projection of human imagination into the cosmos: ancient people looked at the stars and thought they saw mythical beings, beasts and cultural touchstones among the stars. On the other hand, most asterisms are relatively new. Most are small patterns within a constellation, although some are large patterns made of bright stars from several constellations. There’s nothing official about asterisms, but people on all parts of Earth still love them and enjoy them.

Stars in a constellation all lie at different distances from the Earth. For example, the three stars comprising the constellation of Triangulum are between 35 and 127 light-years away. While a constellation may look as if all of its stars are the same distance away, in reality that is only because, as we now know, stars vary in size and brightness, so two stars which appear to be the same brightness in the sky may actually be separated by vast distances. This means that an alien astronomer on a planet a hundred light years from Earth would know very different constellations, because they would see the night sky from a completely different perspective.

The Plough, for example, (also known as the Big Dipper or King Charles’ Wain) is a pattern of seven stars within the constellation of Ursa Major, the Great Bear. It is undoubtedly the most famous asterism in the sky, and not least because of its usefulness as a signpost for other stars and constellations. In the southern hemisphere, five stars comprise the Southern Cross, an asterism within the constellation of Crux. Sometimes, asterisms comprise stars of more than one constellation: for example, the glorious Summer Triangle, so prominent in the northern hemisphere sky between June and September, comprises stars in Cygnus, Lyra and Aquila. In Sagittarius there is the famous “teapot” asterism, inside which lies the location of the centre of our Milky Way galaxy.

There is no hard and fast rule for what constitutes an asterism: usually it’s a group of prominent stars in a simple pattern that are among the first that people recognise when they are learning their way around the sky.

Many constellations are well-known: Orion, Ursa Major, Cassiopeia, Cygnus , the famous star patterns you learn first when bitten by the bug of astronomy. But perhaps the most recognized are those that comprise the star signs of the zodiac: Aries, Libra, Pisces, Virgo and the eight others which had a special significance for astrologers, more than two thousand years ago when the first astrological charts were drawn by the Babylonians (although the history of the zodiac may go back further). The twelve constellations of the zodiac had a special significance because, together, they comprise the path through the heavens that the sun appears to follow during one year.

Of course, we now know that the sun does not follow this path, that it is the Earth which is moving and not the sun. We also know that since the first astrological charts were created, a gradual tilting of the Earth’s axis, causing an effect known as the precession of the equinoxes, means that the sun now appears to pass though a thirteenth constellation of the zodiac: that of Ophiuchus, the serpent-bearer. This has had the knock-on effect of changing the dates when the sun “passes through” each zodiacal constellation, so that, for example, Ophiuchus occupies most of the days in the calendar where the astrological sign of Sagittarius resides, and Aquarius largely occupies the space where Pisces is.  Although this does of course invalidate the dates of the astrological star-signs seen in the horoscopes of tabloid newspapers, as well as the dates of the supposed star sign which people are “born under,” it should be remembered that the astrological zodiac has little resemblance to the actual constellations which the star signs represent: astrology simply divides the 360-degree heavens into twelve equal segments, without regard for how many degrees each constellation actually spans in the sky. This means that an astrological star sign can encompass more than one constellation, and therefore the astrological zodiac should be seen as largely symbolic rather than factual. It has nothing to do with the real universe.

It was the Greeks and Romans who, between them, first recognized and named the constellations of the Northern Hemisphere, listed around the second century A.D., although doubtless prehistoric humans had created their own constellations long before them. Indeed, each human culture has seen its own mythology and creation stories in the stars since time immemorial. Not surprisingly, the Greeks and Romans saw the heroes, heroines and beasts from their mythologies in the sky: Pegasus, Orion, Taurus, Cassiopeia and many others.

The first list of constellations we know of appears in Ptolemy’s second-century Almagest, which was his treatise on the apparent motions and stars and planets, and which established a geocentric view of the universe which was to persist for 1200 years. While the Greeks and Romans bequeathed us the names of the Northern Hemisphere constellations, it was Arabs who were the first to name the individual stars composing each: Islamic scholars were the first to systematically map the skies.  Many of these Arabic star names have survived until today: Aldebaran, Alcor, Altair, Algol. The prefix “Al-” is a sure indication of an Islamic name: it simply means “the.” Hence, for example, Aldebaran is “the follower,” because it appears to follow the Hyades star cluster that makes up the head of the constellation of Taurus the Bull.

Certain constellations have acquired special significance over the millennia because of their appearance marking the onset of seasons, telling ancient peoples when to sow or reap their crops, when to collect food or animal skins. Because of the Earth’s orbit around the sun, different constellations become visible at different times of the year. For example, in the Northern Hemisphere the appearance of Orion in the early morning sky warns of the onset of autumn, that temperatures will shortly start to drop. The rising of the Summer Triangle to prominence in the northern sky is a harbinger of summer. Thus, to ancient cultures constellations were more than just patterns: they marked the passing of the seasons, of the years, of life itself.

The 48 constellations of the Northern Hemisphere, and their boundaries, were formally recognized by the International Astronomical Union in 1928 and the official list published in 1930. The story of the constellations of the Southern Hemisphere, however, is a little more complicated. Many of these were named by Italian, Dutch and Portuguese explorers of the 14th to 16th centuries. So as constellations there are objects and beasts associated with the great seafaring voyages of that epoch: Telescopium, the telescope; Octans, the octant; Dorado, the swordfish; Vela, the ship’s sails; Hydrus, the sea serpent. But explorers and observers often proposed different constellations with conflicting names, often to please their patrons. It was not until the 19th century that the current list of southern constellations was agreed upon and adopted.

From an observer’s perspective, from sunset to dawn the sky appears to revolve around one fixed point in the sky. This location in the heavens is what the Earth’s axis points at and is called the celestial pole. In the Northern Hemisphere, Polaris (the pole star) lies very close to the celestial pole, whereas in the Southern Hemisphere there is no bright star marking the location. Those constellations which revolve around the celestial pole yet do not dip below the horizon during the night, due to their proximity to it, are known as circumpolar constellations. In other words, for an observer these constellations will never set. There are five of these in the Northern Hemisphere: Ursa Major, Ursa Minor, Draco, Cassiopeia and Cepheus. The Southern Hemisphere has three: Crux, Centaurus and Carina.

The constellations are not difficult for a budding astronomer to learn. There are many excellent resources and planetarium-type programs available free online. It is certainly worth learning to recognize the constellations, even if sometimes we strain to see what the ancients did!

Bottom line: Constellations and asterisms are patterns of stars. Some asterisms consist of stars from different constellations, and some asterisms are part of one constellation.

from EarthSky https://ift.tt/2YyXaI6

Venus’ final month in the evening sky

May will be the planet Venus’ last full month in the western twilight sky for the year 2020. On June 3, Venus will swing between the Earth and sun in its orbit, reaching the point called inferior conjunction by astronomers. Afterwards it’ll transition over to the eastern sky before sunup. But what an exciting month for Venus this will be! We’ll all be able to watch it sink closer to the western horizon day by day, finally disappearing in the sunset glare.

Those with telescopes will see that – as it gets closer to the sunset, preparing to go between us and the sun – more and more of its day side will be turned away from our direction in space: we’ll see Venus as a waning crescent. What’s more, the sun’s other inner planet – Mercury – will join the scene in the west after sunset beginning around mid-May. All in all, a fascinating month to watch the western sky after sunset!

Given clear skies, you can’t miss seeing Venus in your western sky after sunset. After all, dazzling Venus ranks as the third-brightest celestial body to light up the heavens, after the sun and moon. Some people can actually see Venus in a daytime sky, but we mere mortals can expect to see this bright beauty some 15 to 30 minutes after sundown.

Although Venus plunges closer and closer to the sunset each day, this world will be rather easy to view for the next few weeks. Venus stays out longer after dark at more northerly latitudes, however. At present – May 5, 2020 – Venus stays out for over 3 hours after sunset at mid-northern latitudes, 2 1/2 hours after the sun at the equator, and 1 3/4 hours after sunset at temperate latitudes in the Southern Hemisphere.

Have a telescope? This is by far the most exciting time to view Venus through the telescope. That’s because Venus in its faster orbit around the sun is rapidly catching up with our planet Earth. Therefore, Venus’ disk size is increasing while its phase is waning (shrinking). On May 5, 2020, Venus is 21% illuminated in sunshine. A week from now – May 12, 2020 – Venus will be 14% illuminated; and two weeks from now – May 19, 2020 – Venus will be 8% illuminated. Three weeks later – May 26, 2020 – Venus will be 3% illuminated. All the while, the disk size will have increased by 80%.

Keep in mind that you get a crisper view of Venus’ phase in a twilight or daytime sky than after dark. That’s because Venus’ glare is so overwhelming at nighttime.

When Galileo (1564-1642) first saw the phases of Venus through the telescope, he came to the realization that Venus must orbit the sun instead of orbiting Earth. This observation countered the widely-held notion at the time that Venus orbits Earth.

By the way, the planet Mercury entered the evening sky on May 4, 2020. However, the innermost planet probably won’t climb high enough from the sunset glare to become visible for another week or two. Fortunately, we can use Venus to help us locate Mercury in May 2020. Throughout the month, Venus will be falling toward the sunset while Mercury will be climbing away. On or near May 21, 2020, watch for these two worlds to be within one degree of one another on the sky’s dome. If you can see Venus with the eye alone, then aim binoculars at Venus to see Mercury sharing a single binocular field with Venus.

Depending on where you live worldwide, the planets Mercury and Venus will couple up most closely on the sky’s dome on May 21 or May 22, 2020. If you can see Venus, but not Mercury, aim binoculars at Venus to see Mercury and Venus taking stage in a single binocular field.

Then, only a few to several days after the Venus/Mercury conjunction, watch for the slender waxing lunar crescent to join up with Mercury and Venus at dusk. Think photo opportunity! Thereafter, Venus will continue to fall downward while Mercury will soar upward. Mercury will reach its greatest eastern elongation (greatest angular distance) from the setting sun on June 4, 2020.

Have a telescope? You’ll see the phases of the moon and Venus nearly match on or around May 24, 2020.

Bottom line: Before Venus transits to the morning sky, it will be fun to watch this upcoming month, with or without a telescope. Find an unobstructed horizon in the direction of sunset, and you might be able to view Venus in the western evening dusk until the month’s end.

from EarthSky https://ift.tt/2W5KUNK

May will be the planet Venus’ last full month in the western twilight sky for the year 2020. On June 3, Venus will swing between the Earth and sun in its orbit, reaching the point called inferior conjunction by astronomers. Afterwards it’ll transition over to the eastern sky before sunup. But what an exciting month for Venus this will be! We’ll all be able to watch it sink closer to the western horizon day by day, finally disappearing in the sunset glare.

Those with telescopes will see that – as it gets closer to the sunset, preparing to go between us and the sun – more and more of its day side will be turned away from our direction in space: we’ll see Venus as a waning crescent. What’s more, the sun’s other inner planet – Mercury – will join the scene in the west after sunset beginning around mid-May. All in all, a fascinating month to watch the western sky after sunset!

Given clear skies, you can’t miss seeing Venus in your western sky after sunset. After all, dazzling Venus ranks as the third-brightest celestial body to light up the heavens, after the sun and moon. Some people can actually see Venus in a daytime sky, but we mere mortals can expect to see this bright beauty some 15 to 30 minutes after sundown.

Although Venus plunges closer and closer to the sunset each day, this world will be rather easy to view for the next few weeks. Venus stays out longer after dark at more northerly latitudes, however. At present – May 5, 2020 – Venus stays out for over 3 hours after sunset at mid-northern latitudes, 2 1/2 hours after the sun at the equator, and 1 3/4 hours after sunset at temperate latitudes in the Southern Hemisphere.

Have a telescope? This is by far the most exciting time to view Venus through the telescope. That’s because Venus in its faster orbit around the sun is rapidly catching up with our planet Earth. Therefore, Venus’ disk size is increasing while its phase is waning (shrinking). On May 5, 2020, Venus is 21% illuminated in sunshine. A week from now – May 12, 2020 – Venus will be 14% illuminated; and two weeks from now – May 19, 2020 – Venus will be 8% illuminated. Three weeks later – May 26, 2020 – Venus will be 3% illuminated. All the while, the disk size will have increased by 80%.

Keep in mind that you get a crisper view of Venus’ phase in a twilight or daytime sky than after dark. That’s because Venus’ glare is so overwhelming at nighttime.

When Galileo (1564-1642) first saw the phases of Venus through the telescope, he came to the realization that Venus must orbit the sun instead of orbiting Earth. This observation countered the widely-held notion at the time that Venus orbits Earth.

By the way, the planet Mercury entered the evening sky on May 4, 2020. However, the innermost planet probably won’t climb high enough from the sunset glare to become visible for another week or two. Fortunately, we can use Venus to help us locate Mercury in May 2020. Throughout the month, Venus will be falling toward the sunset while Mercury will be climbing away. On or near May 21, 2020, watch for these two worlds to be within one degree of one another on the sky’s dome. If you can see Venus with the eye alone, then aim binoculars at Venus to see Mercury sharing a single binocular field with Venus.

Depending on where you live worldwide, the planets Mercury and Venus will couple up most closely on the sky’s dome on May 21 or May 22, 2020. If you can see Venus, but not Mercury, aim binoculars at Venus to see Mercury and Venus taking stage in a single binocular field.

Then, only a few to several days after the Venus/Mercury conjunction, watch for the slender waxing lunar crescent to join up with Mercury and Venus at dusk. Think photo opportunity! Thereafter, Venus will continue to fall downward while Mercury will soar upward. Mercury will reach its greatest eastern elongation (greatest angular distance) from the setting sun on June 4, 2020.

Have a telescope? You’ll see the phases of the moon and Venus nearly match on or around May 24, 2020.

Bottom line: Before Venus transits to the morning sky, it will be fun to watch this upcoming month, with or without a telescope. Find an unobstructed horizon in the direction of sunset, and you might be able to view Venus in the western evening dusk until the month’s end.

from EarthSky https://ift.tt/2W5KUNK

4 amazing astronomical discoveries from ancient Greece

Earth and moon as seen by the Galileo spacecraft. Image via NASA/ The Conversation.

By Gareth Dorrian, University of Birmingham and Ian Whittaker, Nottingham Trent University

“The Histories” by Herodotus (484 B.C. to 425 B.C.) offers a remarkable window into the world as it was known to the ancient Greeks in the mid fifth century B.C. Almost as interesting as what they knew, however, is what they did not know. This sets the baseline for the remarkable advances in their understanding over the next few centuries – simply relying on what they could observe with their own eyes.

Herodotus claimed that Africa was surrounded almost entirely by sea. How did he know this? He recounts the story of Phoenician sailors who were dispatched by King Neco II of Egypt (about 600 B.C.), to sail around continental Africa, in a clockwise fashion, starting in the Red Sea. This story, if true, recounts the earliest known circumnavigation of Africa, but also contains an interesting insight into the astronomical knowledge of the ancient world.

The voyage took several years. Having rounded the southern tip of Africa, and following a westerly course, the sailors observed the sun as being on their right hand side, above the northern horizon. This observation simply did not make sense at the time because they didn’t yet know that the Earth has a spherical shape, and that there is a southern hemisphere.

1. The planets orbit the sun

A few centuries later, there had been a lot of progress. Aristarchus of Samos (310 B.C. to 230 B.C.) argued that the sun was the “central fire” of the cosmos and he placed all of the then known planets in their correct order of distance around it. This is the earliest known heliocentric theory of the solar system.

Unfortunately, the original text in which he makes this argument has been lost to history, so we cannot know for certain how he worked it out. Aristarchus knew the sun was much bigger than the Earth or the moon, and he may have surmised that it should therefore have the central position in the solar system.

Nevertheless it is a jaw-dropping finding, especially when you consider that it wasn’t rediscovered until the 16th century, by Nicolaus Copernicus, who even acknowledged Aristarchus during the development of his own work.

2. The size of the moon

One of Aristarchus’ books that did survive is about the sizes and distances of the sun and moon. In this remarkable treatise, Aristarchus laid out the earliest known attempted calculations of the relative sizes and distances to the sun and moon.

It had long been observed that the sun and moon appeared to be of the same apparent size in the sky, and that the sun was further away. They realized this from solar eclipses, caused by the moon passing in front of the sun at a certain distance from Earth.

Also, at the instant when the moon is at first or third quarter, Aristarchus reasoned that the sun, Earth, and moon would form a right-angled triangle.

As Pythagoras had determined how the lengths of a triangle’s sides were related a couple of centuries earlier, Aristarchus used the triangle to estimate that the distance to the sun was between 18 and 20 times the distance to the moon. He also estimated that the size of the moon was approximately one-third that of Earth, based on careful timing of lunar eclipses.

A 10th century reproduction of a diagram by Aristarchus showing some of the geometry he used in his calculations. Image via Wikipedia.

While his estimated distance to the sun was too low (the actual ratio is 390), on account of the lack of telescopic precision available at the time, the value for the ratio of the size of the Earth to the moon is surprisingly accurate (the moon has a diameter 0.27 times that of Earth).

Today, we know the size and distance to the moon accurately by a variety of means, including precise telescopes, radar observations and laser reflectors left on the surface by Apollo astronauts.

3. The Earth’s circumference

Eratosthenes (276BC to 195 B.C.) was chief librarian at the Great Library of Alexandria, and a keen experimentalist. Among his many achievements was the earliest known calculation of the circumference of the Earth. Pythagoras is generally regarded as the earliest proponent of a spherical Earth, although apparently not its size. Eratosthenes’ famous and yet simple method relied on measuring the different lengths of shadows cast by poles stuck vertically into the ground, at midday on the summer solstice, at different latitudes.

The sun is sufficiently far away that, wherever its rays arrive at Earth, they are effectively parallel, as had previously been shown by Aristarchus. So the difference in the shadows demonstrated how much the Earth’s surface curved. Eratosthenes used this to estimate the Earth’s circumference as approximately 25,000 miles (40,000 km). This is within a couple of percent of the actual value, as established by modern geodesy (the science of the Earth’s shape).

Later, another scientist called Posidonius (135 B.C. to 51 B.C.) used a slightly different method and arrived at almost exactly the same answer. Posidonius lived on the island of Rhodes for much of his life. There he observed the bright star Canopus would lie very close to the horizon. However, when in Alexandria, in Egypt, he noted Canopus would ascend to some 7.5 degrees above the horizon.

Given that 7.5 degrees is 1/48th of a circle, he multiplied the distance from Rhodes to Alexandria by 48, and arrived at a value also of approximately 25,000 miles (40,000 km).

4. The first astronomical calculator

The world’s oldest surviving mechanical calculator is the Antikythera Mechanism. The amazing device was discovered in an ancient shipwreck off the Greek island of Antikythera in 1900.

The device is now fragmented by the passage of time, but when intact it would have appeared as a box housing dozens of finely machined bronze gear wheels. When manually rotated by a handle, the gears spun dials on the exterior showing the phases of the moon, the timing of lunar eclipses, and the positions of the five planets then known (Mercury, Venus, Mars, Jupiter, and Saturn) at different times of the year. This even accounted for their retrograde motion – an illusionary change in the movement of planets through the sky.

We don’t know who built it, but it dates to some time between the third and first centuries B.C., and may even have been the work of Archimedes. Gearing technology with the sophistication of the Antikythera mechanism was not seen again for a thousand years.

Sadly, the vast majority of these works were lost to history and our scientific awakening was delayed by millennia. As a tool for introducing scientific measurement, the techniques of Eratosthenes are relatively easy to perform and require no special equipment, allowing those just beginning their interest in science to understand by doing, experimenting and, ultimately, following in the footsteps of some of the first scientists.

One can but speculate where our civilization might be now if this ancient science had continued unabated.

Gareth Dorrian, Post Doctoral Research Fellow in Space Science, University of Birmingham and Ian Whittaker, Lecturer in Physics, Nottingham Trent University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bottom line: Four 4 astronomical discoveries from ancient Greece.

from EarthSky https://ift.tt/2WqJv3q

Earth and moon as seen by the Galileo spacecraft. Image via NASA/ The Conversation.

By Gareth Dorrian, University of Birmingham and Ian Whittaker, Nottingham Trent University

“The Histories” by Herodotus (484 B.C. to 425 B.C.) offers a remarkable window into the world as it was known to the ancient Greeks in the mid fifth century B.C. Almost as interesting as what they knew, however, is what they did not know. This sets the baseline for the remarkable advances in their understanding over the next few centuries – simply relying on what they could observe with their own eyes.

Herodotus claimed that Africa was surrounded almost entirely by sea. How did he know this? He recounts the story of Phoenician sailors who were dispatched by King Neco II of Egypt (about 600 B.C.), to sail around continental Africa, in a clockwise fashion, starting in the Red Sea. This story, if true, recounts the earliest known circumnavigation of Africa, but also contains an interesting insight into the astronomical knowledge of the ancient world.

The voyage took several years. Having rounded the southern tip of Africa, and following a westerly course, the sailors observed the sun as being on their right hand side, above the northern horizon. This observation simply did not make sense at the time because they didn’t yet know that the Earth has a spherical shape, and that there is a southern hemisphere.

1. The planets orbit the sun

A few centuries later, there had been a lot of progress. Aristarchus of Samos (310 B.C. to 230 B.C.) argued that the sun was the “central fire” of the cosmos and he placed all of the then known planets in their correct order of distance around it. This is the earliest known heliocentric theory of the solar system.

Unfortunately, the original text in which he makes this argument has been lost to history, so we cannot know for certain how he worked it out. Aristarchus knew the sun was much bigger than the Earth or the moon, and he may have surmised that it should therefore have the central position in the solar system.

Nevertheless it is a jaw-dropping finding, especially when you consider that it wasn’t rediscovered until the 16th century, by Nicolaus Copernicus, who even acknowledged Aristarchus during the development of his own work.

2. The size of the moon

One of Aristarchus’ books that did survive is about the sizes and distances of the sun and moon. In this remarkable treatise, Aristarchus laid out the earliest known attempted calculations of the relative sizes and distances to the sun and moon.

It had long been observed that the sun and moon appeared to be of the same apparent size in the sky, and that the sun was further away. They realized this from solar eclipses, caused by the moon passing in front of the sun at a certain distance from Earth.

Also, at the instant when the moon is at first or third quarter, Aristarchus reasoned that the sun, Earth, and moon would form a right-angled triangle.

As Pythagoras had determined how the lengths of a triangle’s sides were related a couple of centuries earlier, Aristarchus used the triangle to estimate that the distance to the sun was between 18 and 20 times the distance to the moon. He also estimated that the size of the moon was approximately one-third that of Earth, based on careful timing of lunar eclipses.

A 10th century reproduction of a diagram by Aristarchus showing some of the geometry he used in his calculations. Image via Wikipedia.

While his estimated distance to the sun was too low (the actual ratio is 390), on account of the lack of telescopic precision available at the time, the value for the ratio of the size of the Earth to the moon is surprisingly accurate (the moon has a diameter 0.27 times that of Earth).

Today, we know the size and distance to the moon accurately by a variety of means, including precise telescopes, radar observations and laser reflectors left on the surface by Apollo astronauts.

3. The Earth’s circumference

Eratosthenes (276BC to 195 B.C.) was chief librarian at the Great Library of Alexandria, and a keen experimentalist. Among his many achievements was the earliest known calculation of the circumference of the Earth. Pythagoras is generally regarded as the earliest proponent of a spherical Earth, although apparently not its size. Eratosthenes’ famous and yet simple method relied on measuring the different lengths of shadows cast by poles stuck vertically into the ground, at midday on the summer solstice, at different latitudes.

The sun is sufficiently far away that, wherever its rays arrive at Earth, they are effectively parallel, as had previously been shown by Aristarchus. So the difference in the shadows demonstrated how much the Earth’s surface curved. Eratosthenes used this to estimate the Earth’s circumference as approximately 25,000 miles (40,000 km). This is within a couple of percent of the actual value, as established by modern geodesy (the science of the Earth’s shape).

Later, another scientist called Posidonius (135 B.C. to 51 B.C.) used a slightly different method and arrived at almost exactly the same answer. Posidonius lived on the island of Rhodes for much of his life. There he observed the bright star Canopus would lie very close to the horizon. However, when in Alexandria, in Egypt, he noted Canopus would ascend to some 7.5 degrees above the horizon.

Given that 7.5 degrees is 1/48th of a circle, he multiplied the distance from Rhodes to Alexandria by 48, and arrived at a value also of approximately 25,000 miles (40,000 km).

4. The first astronomical calculator

The world’s oldest surviving mechanical calculator is the Antikythera Mechanism. The amazing device was discovered in an ancient shipwreck off the Greek island of Antikythera in 1900.

The device is now fragmented by the passage of time, but when intact it would have appeared as a box housing dozens of finely machined bronze gear wheels. When manually rotated by a handle, the gears spun dials on the exterior showing the phases of the moon, the timing of lunar eclipses, and the positions of the five planets then known (Mercury, Venus, Mars, Jupiter, and Saturn) at different times of the year. This even accounted for their retrograde motion – an illusionary change in the movement of planets through the sky.

We don’t know who built it, but it dates to some time between the third and first centuries B.C., and may even have been the work of Archimedes. Gearing technology with the sophistication of the Antikythera mechanism was not seen again for a thousand years.

Sadly, the vast majority of these works were lost to history and our scientific awakening was delayed by millennia. As a tool for introducing scientific measurement, the techniques of Eratosthenes are relatively easy to perform and require no special equipment, allowing those just beginning their interest in science to understand by doing, experimenting and, ultimately, following in the footsteps of some of the first scientists.

One can but speculate where our civilization might be now if this ancient science had continued unabated.

Gareth Dorrian, Post Doctoral Research Fellow in Space Science, University of Birmingham and Ian Whittaker, Lecturer in Physics, Nottingham Trent University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bottom line: Four 4 astronomical discoveries from ancient Greece.

from EarthSky https://ift.tt/2WqJv3q