Hubble captures a dozen galaxy doppelgangers

View larger. | A Hubble Space Telescope image of the 4 visible arcs associated with the Sunburst Arc galaxy. This exceedingly distant galaxy helps create one of the brightest gravitational lenses known. Within these 4 visible arcs are at least 12 images – 12 doppelgangers, or illusory images – of the galaxy. Image via ESA/NASA/E. Rivera-Thorsen et al./SpaceTelescope.org.

Not all the lights in this Hubble Space Telescope image – released on November 7, 2019 – are stars. Many are galaxies in a galaxy cluster 4.6 billion light-years away. See the four partial arcs in the image, three in the upper right and the fourth on the lower left? These arcs are an illusion in space, created via the light of an even-more-distant galaxy – 11 billion light-years away – behind the galaxy cluster. The light of the very distant galaxy is bent by the closer, super-massive cluster. This is an example of gravitational lensing, predicted by Einstein’s relativity theory. The distant galaxy creates one of the brightest gravitational lenses known, which is why astronomers call it the Sunburst Arc.

Scientists recently studied the Sunburst Arc, using the Hubble Telescope. Their peer-reviewed study revealed the 12 doppelganger galaxies within those four arcs of light. The study was published in the journal Science on November 8. A statement at SpaceTelescope.org explained:

The mass of the galaxy cluster is large enough to bend and magnify the light from the more distant galaxy behind it. This process leads not only to a deformation of the light from the object, but also to a multiplication of the image of the lensed galaxy.

In the case of the Sunburst Arc, the lensing effect led to at least 12 images of the galaxy, distributed over four major arcs. Three of these arcs are visible in the top right of the image [above], while one counterarc is visible in the lower left — partially obscured by a bright foreground star within the Milky Way.

These scientists said that, using the Hubble Telescope and the effect of gravitational lensing – the bending of the light of distant objects in space by massive intervening objects – they can study distant objects otherwise too faint and too small even for Hubble’s instruments. That’s because, they said:

The lens makes various images of the Sunburst Arc between 10 and 30 times brighter.

This brightening via gravitational lensing lets the Hubble telescope view structures within the very distant galaxy as small as 520 light-years across! That’s an incredibly rare, detailed observation for an object 11 billion light-years away. In fact, that resolution – the seeing of features as small as 520 light-years across – compares reasonably well, these astronomers said, with star forming regions in galaxies in the space near our own Milky Way galaxy.

So the gravitational lensing effect of the Sunburst Arc gives astronomers a window on the very early universe. That’s because, as we all know, a galaxy that’s 11 billion light-years away is seen – not as it is now – but as it was 11 billion years ago. The astronomers said this essential fact about our universe – which happens because light doesn’t travel infinitely fast, but instead at a finite speed (186,000 miles per second or 299,992 km/s) – is letting these astronomers study a time in the early universe known as the epoch of reionization. That epoch began only 150 million years after the Big Bang. To learn more about that aspect of this study, read toward the bottom of the astronomers’ statement.

In the meantime, contemplate the images below … the multiple arcs of the Sunburst Arc, each one containing ghost images of the galaxy. Don’t we live in an interesting universe?

EarthSky 2020 lunar calendars are available! They make great gifts. Order now. Going fast!

Here’s a close-up of a Hubble image, showing one of 4 arcs formed of the light from the Sunburst Arc galaxy. Created by strong gravitational lensing, this bright arc of light contains at least 6 copies of the image of the very distant galaxy. Image via ESA/NASA/E. Rivera-Thorsen et al./SpaceTelescope.org.

Hubble Space Telescope image of yet another of the 4 arcs formed of the light from the Sunburst Arc galaxy. This isn’t a material object in space. It’s an illusion of light and gravity, created by what’s called gravitational lensing. This bright arc of light contains at least 4 copies of the image of the Sunburst Arc galaxy. Image via ESA/NASA/E. Rivera-Thorsen et al/SpaceTelescope.org.

This Hubble Space Telescope images shows another one of 4 arcs formed of the light from the Sunburst Arc galaxy. Created by strong gravitational lensing, this bright arc of light shows “at least” one copy of the image of the galaxy. There’s also a foreground star in this image, partially blocking the view of the arc. Image via ESA/NASA/E. Rivera-Thorsen et al./SpaceTelescope.org.

Bottom line: The Sunburst Arc galaxy is part of a gravitational lens system. That is, it’s located behind a massive galaxy cluster, as seen from Earth, and the intervening cluster has bent its light into multiple arcs. A recent study revealed that the 4 bright arcs in this Hubble image contain 12 images of the galaxy – cosmic doppelgangers – 11 billion light-years away.

Source: Bright ionizing escape at high resolution from multiply imaged, gravitationally lensed galaxy

Via SpaceTelescope.org

from EarthSky https://ift.tt/34Tp4yo

View larger. | A Hubble Space Telescope image of the 4 visible arcs associated with the Sunburst Arc galaxy. This exceedingly distant galaxy helps create one of the brightest gravitational lenses known. Within these 4 visible arcs are at least 12 images – 12 doppelgangers, or illusory images – of the galaxy. Image via ESA/NASA/E. Rivera-Thorsen et al./SpaceTelescope.org.

Not all the lights in this Hubble Space Telescope image – released on November 7, 2019 – are stars. Many are galaxies in a galaxy cluster 4.6 billion light-years away. See the four partial arcs in the image, three in the upper right and the fourth on the lower left? These arcs are an illusion in space, created via the light of an even-more-distant galaxy – 11 billion light-years away – behind the galaxy cluster. The light of the very distant galaxy is bent by the closer, super-massive cluster. This is an example of gravitational lensing, predicted by Einstein’s relativity theory. The distant galaxy creates one of the brightest gravitational lenses known, which is why astronomers call it the Sunburst Arc.

Scientists recently studied the Sunburst Arc, using the Hubble Telescope. Their peer-reviewed study revealed the 12 doppelganger galaxies within those four arcs of light. The study was published in the journal Science on November 8. A statement at SpaceTelescope.org explained:

The mass of the galaxy cluster is large enough to bend and magnify the light from the more distant galaxy behind it. This process leads not only to a deformation of the light from the object, but also to a multiplication of the image of the lensed galaxy.

In the case of the Sunburst Arc, the lensing effect led to at least 12 images of the galaxy, distributed over four major arcs. Three of these arcs are visible in the top right of the image [above], while one counterarc is visible in the lower left — partially obscured by a bright foreground star within the Milky Way.

These scientists said that, using the Hubble Telescope and the effect of gravitational lensing – the bending of the light of distant objects in space by massive intervening objects – they can study distant objects otherwise too faint and too small even for Hubble’s instruments. That’s because, they said:

The lens makes various images of the Sunburst Arc between 10 and 30 times brighter.

This brightening via gravitational lensing lets the Hubble telescope view structures within the very distant galaxy as small as 520 light-years across! That’s an incredibly rare, detailed observation for an object 11 billion light-years away. In fact, that resolution – the seeing of features as small as 520 light-years across – compares reasonably well, these astronomers said, with star forming regions in galaxies in the space near our own Milky Way galaxy.

So the gravitational lensing effect of the Sunburst Arc gives astronomers a window on the very early universe. That’s because, as we all know, a galaxy that’s 11 billion light-years away is seen – not as it is now – but as it was 11 billion years ago. The astronomers said this essential fact about our universe – which happens because light doesn’t travel infinitely fast, but instead at a finite speed (186,000 miles per second or 299,992 km/s) – is letting these astronomers study a time in the early universe known as the epoch of reionization. That epoch began only 150 million years after the Big Bang. To learn more about that aspect of this study, read toward the bottom of the astronomers’ statement.

In the meantime, contemplate the images below … the multiple arcs of the Sunburst Arc, each one containing ghost images of the galaxy. Don’t we live in an interesting universe?

EarthSky 2020 lunar calendars are available! They make great gifts. Order now. Going fast!

Here’s a close-up of a Hubble image, showing one of 4 arcs formed of the light from the Sunburst Arc galaxy. Created by strong gravitational lensing, this bright arc of light contains at least 6 copies of the image of the very distant galaxy. Image via ESA/NASA/E. Rivera-Thorsen et al./SpaceTelescope.org.

Hubble Space Telescope image of yet another of the 4 arcs formed of the light from the Sunburst Arc galaxy. This isn’t a material object in space. It’s an illusion of light and gravity, created by what’s called gravitational lensing. This bright arc of light contains at least 4 copies of the image of the Sunburst Arc galaxy. Image via ESA/NASA/E. Rivera-Thorsen et al/SpaceTelescope.org.

This Hubble Space Telescope images shows another one of 4 arcs formed of the light from the Sunburst Arc galaxy. Created by strong gravitational lensing, this bright arc of light shows “at least” one copy of the image of the galaxy. There’s also a foreground star in this image, partially blocking the view of the arc. Image via ESA/NASA/E. Rivera-Thorsen et al./SpaceTelescope.org.

Bottom line: The Sunburst Arc galaxy is part of a gravitational lens system. That is, it’s located behind a massive galaxy cluster, as seen from Earth, and the intervening cluster has bent its light into multiple arcs. A recent study revealed that the 4 bright arcs in this Hubble image contain 12 images of the galaxy – cosmic doppelgangers – 11 billion light-years away.

Source: Bright ionizing escape at high resolution from multiply imaged, gravitationally lensed galaxy

Via SpaceTelescope.org

from EarthSky https://ift.tt/34Tp4yo

Astronomers catch a record-setting X-ray burst

On August 20, 2019, a special telescope mounted on the outside of the International Space Station (ISS) detected a sudden spike of X-rays from a distant neutron star that’s also a pulsar. The explosion, which astronomers classify as a Type I X-ray burst, released as much energy in 20 seconds as the sun does in nearly 10 days. Turns out it was a massive thermonuclear flash on the pulsar, which is labeled J1808 by astronomers. This pulsar – the crushed remains of a star that long ago exploded as a supernova – is located about 11,400 light-years away in the direction of our constellation Sagittarius the Archer. NASA said these observations of the record-setting X-ray spike on this object:

… reveal many phenomena that have never been seen together in a single burst. In addition, the subsiding fireball briefly brightened again for reasons astronomers cannot yet explain.

The telescope aboard ISS is interesting, too. It’s called NICER, which stands for Neutron star Interior Composition Explorer, and it was launched to ISS in 2017. It has made multiple discoveries before this, but, according to lead researcher Peter Bult of NASA’s Goddard Space Flight Center and the University of Maryland:

This burst was outstanding. We see a two-step change in brightness, which we think is caused by the ejection of separate layers from the pulsar surface, and other features that will help us decode the physics of these powerful events.

A paper describing the observations and resulting analysis has been published by the peer-reviewed Astrophysical Journal Letters and is available online.

EarthSky 2020 lunar calendars are available! They make great gifts. Order now. Going fast!

View larger. | Artist’s concept via NASA.

Neutron stars are highly compact stars, the crushed remains of a massive star that ran out of fuel, collapsed under its own weight, and exploded as a supernova. Pulsars are characterized by their rapid spin and – in the case of X-ray pulsars – by the X-ray-emitting hot spots at their magnetic poles. As the object spins, it sweeps the hot spots across our line of sight, producing regular pulses of high-energy radiation. We observe the pulses, and so call the object a pulsar. NASA explained that J1808:

… spins at a dizzying 401 rotations each second, and is one member of a binary system. Its companion is a brown dwarf, an object larger than a giant planet yet too small to be a star. A steady stream of hydrogen gas flows from the companion toward the neutron star, and it accumulates in a vast storage structure called an accretion disk.

Gas in accretion disks doesn’t move inward easily. But every few years, the disks around pulsars like J1808 become so dense that a large amount of the gas becomes ionized, or stripped of its electrons. This makes it more difficult for light to move through the disk. The trapped energy starts a runaway process of heating and ionization that traps yet more energy. The gas becomes more resistant to flow and starts spiraling inward, ultimately falling onto the pulsar.

Hydrogen raining onto the surface forms a hot, ever-deepening global ‘sea.’ At the base of this layer, temperatures and pressures increase until hydrogen nuclei fuse to form helium nuclei, which produces energy – a process at work in the core of our sun.

Zaven Arzoumanian, who is deputy PI for NICER and a co-author on the new paper, said:

The helium settles out and builds up a layer of its own. Once the helium layer is a few meters deep, the conditions allow helium nuclei to fuse into carbon. Then the helium erupts explosively and unleashes a thermonuclear fireball across the entire pulsar surface.

Hence, the X-ray spike.

These astronomers said a concept called the Eddington limit – named for English astrophysicist Sir Arthur Eddington – also comes into play here. The Eddington limit is a theoretical upper limit to the mass of a star, or, as these astronomers described it:

… the maximum radiation intensity a star can have before that radiation causes the star to expand. This point depends strongly on the composition of the material lying above the emission source.

Co-author Deepto Chakrabarty of MIT said:

Our study exploits this longstanding concept in a new way. We are apparently seeing the Eddington limit for two different compositions in the same X-ray burst. This is a very powerful and direct way of following the nuclear burning reactions that underlie the event.

In other words, as the burst started, NICER data showed that its X-ray brightness leveled off for almost a second, and then increased again at a slower pace. NASA said:

The researchers interpret this ‘stall’ as the moment when the energy of the blast built up enough to blow the pulsar’s hydrogen layer into space.

The fireball continued to build for another two seconds and then reached its peak, blowing off the more massive helium layer. The helium expanded faster, overtook the hydrogen layer before it could dissipate, and then slowed, stopped and settled back down onto the pulsar’s surface.

Following this phase, the pulsar briefly brightened again by roughly 20 percent for reasons the team does not yet understand.

The NICER telescope has provided other cool insights about the exotic objects in our Milky Way galaxy. Visit NICER’s website. Or check out the two videos below. The first is an overview of NICER and what its makers expect it to provide, in terms of insights about neutron stars. The second is a fun video timelapse, showing NICER twisting and turning from its perch on the hull of ISS.

Bottom line: In August, NASA’s NICER telescope aboard ISS observed a sudden spike of X-rays from a neutron star, or pulsar. The star released as much energy in 20 seconds as our sun does in nearly 10 days. Turns out it was a massive thermonuclear flash on a pulsar, the crushed remains of a star that exploded as a supernova long ago.

Source: A NICER Thermonuclear Burst from the Millisecond X-Ray Pulsar SAX J1808.4–3658

Via NASA

from EarthSky https://ift.tt/2qcWJ7J

On August 20, 2019, a special telescope mounted on the outside of the International Space Station (ISS) detected a sudden spike of X-rays from a distant neutron star that’s also a pulsar. The explosion, which astronomers classify as a Type I X-ray burst, released as much energy in 20 seconds as the sun does in nearly 10 days. Turns out it was a massive thermonuclear flash on the pulsar, which is labeled J1808 by astronomers. This pulsar – the crushed remains of a star that long ago exploded as a supernova – is located about 11,400 light-years away in the direction of our constellation Sagittarius the Archer. NASA said these observations of the record-setting X-ray spike on this object:

… reveal many phenomena that have never been seen together in a single burst. In addition, the subsiding fireball briefly brightened again for reasons astronomers cannot yet explain.

The telescope aboard ISS is interesting, too. It’s called NICER, which stands for Neutron star Interior Composition Explorer, and it was launched to ISS in 2017. It has made multiple discoveries before this, but, according to lead researcher Peter Bult of NASA’s Goddard Space Flight Center and the University of Maryland:

This burst was outstanding. We see a two-step change in brightness, which we think is caused by the ejection of separate layers from the pulsar surface, and other features that will help us decode the physics of these powerful events.

A paper describing the observations and resulting analysis has been published by the peer-reviewed Astrophysical Journal Letters and is available online.

EarthSky 2020 lunar calendars are available! They make great gifts. Order now. Going fast!

View larger. | Artist’s concept via NASA.

Neutron stars are highly compact stars, the crushed remains of a massive star that ran out of fuel, collapsed under its own weight, and exploded as a supernova. Pulsars are characterized by their rapid spin and – in the case of X-ray pulsars – by the X-ray-emitting hot spots at their magnetic poles. As the object spins, it sweeps the hot spots across our line of sight, producing regular pulses of high-energy radiation. We observe the pulses, and so call the object a pulsar. NASA explained that J1808:

… spins at a dizzying 401 rotations each second, and is one member of a binary system. Its companion is a brown dwarf, an object larger than a giant planet yet too small to be a star. A steady stream of hydrogen gas flows from the companion toward the neutron star, and it accumulates in a vast storage structure called an accretion disk.

Gas in accretion disks doesn’t move inward easily. But every few years, the disks around pulsars like J1808 become so dense that a large amount of the gas becomes ionized, or stripped of its electrons. This makes it more difficult for light to move through the disk. The trapped energy starts a runaway process of heating and ionization that traps yet more energy. The gas becomes more resistant to flow and starts spiraling inward, ultimately falling onto the pulsar.

Hydrogen raining onto the surface forms a hot, ever-deepening global ‘sea.’ At the base of this layer, temperatures and pressures increase until hydrogen nuclei fuse to form helium nuclei, which produces energy – a process at work in the core of our sun.

Zaven Arzoumanian, who is deputy PI for NICER and a co-author on the new paper, said:

The helium settles out and builds up a layer of its own. Once the helium layer is a few meters deep, the conditions allow helium nuclei to fuse into carbon. Then the helium erupts explosively and unleashes a thermonuclear fireball across the entire pulsar surface.

Hence, the X-ray spike.

These astronomers said a concept called the Eddington limit – named for English astrophysicist Sir Arthur Eddington – also comes into play here. The Eddington limit is a theoretical upper limit to the mass of a star, or, as these astronomers described it:

… the maximum radiation intensity a star can have before that radiation causes the star to expand. This point depends strongly on the composition of the material lying above the emission source.

Co-author Deepto Chakrabarty of MIT said:

Our study exploits this longstanding concept in a new way. We are apparently seeing the Eddington limit for two different compositions in the same X-ray burst. This is a very powerful and direct way of following the nuclear burning reactions that underlie the event.

In other words, as the burst started, NICER data showed that its X-ray brightness leveled off for almost a second, and then increased again at a slower pace. NASA said:

The researchers interpret this ‘stall’ as the moment when the energy of the blast built up enough to blow the pulsar’s hydrogen layer into space.

The fireball continued to build for another two seconds and then reached its peak, blowing off the more massive helium layer. The helium expanded faster, overtook the hydrogen layer before it could dissipate, and then slowed, stopped and settled back down onto the pulsar’s surface.

Following this phase, the pulsar briefly brightened again by roughly 20 percent for reasons the team does not yet understand.

The NICER telescope has provided other cool insights about the exotic objects in our Milky Way galaxy. Visit NICER’s website. Or check out the two videos below. The first is an overview of NICER and what its makers expect it to provide, in terms of insights about neutron stars. The second is a fun video timelapse, showing NICER twisting and turning from its perch on the hull of ISS.

Bottom line: In August, NASA’s NICER telescope aboard ISS observed a sudden spike of X-rays from a neutron star, or pulsar. The star released as much energy in 20 seconds as our sun does in nearly 10 days. Turns out it was a massive thermonuclear flash on a pulsar, the crushed remains of a star that exploded as a supernova long ago.

Source: A NICER Thermonuclear Burst from the Millisecond X-Ray Pulsar SAX J1808.4–3658

Via NASA

from EarthSky https://ift.tt/2qcWJ7J

What makes a cancer test?

The earlier a cancer is picked up, the more likely a person is to survive. And if we can’t stop cancers starting then, detecting them before they cause trouble is the next best thing.

But detecting the almost undetectable comes with significant challenges as these tiny, newly formed cancers are hiding from scientists and doctors amongst a smokescreen of trillions of healthy cells.

Detecting the almost undetectable

To find cancer in the body, first you need something to look for.

A successful cancer test will be able to detect ‘red-flag’ molecules produced by the cancer, revealing its presence. And to pick up disease at a stage where it can be cured with treatment such as surgery, the cancer needs to be compact and contained. Unfortunately, in most cases, this means it’s small enough to lay low. So, to locate these tiny cancers and successfully pick up the small number of ‘red flag’ molecules they’re making, scientists have to get creative.

One type of test that’s seen a lot of investment are those looking for floating bits of cancer cell DNA in the blood.

Professor Paul Pharoah, from the Cancer Research UK Cambridge Centre, says “a very small part of the blood is made up of cell free DNA that’s come from all sorts of places in your body.” Cancer cells can also release DNA into the bloodstream when they die, which could be picked up by testing the blood. But it’s no mean feat.

“The proportion of DNA from cancer is even smaller and therefore your test has to be incredibly sensitive to look beyond all of these extra DNA pieces,” says Pharoah, adding that urine, poo and breath may also contain signs of cancer.

The secret to a good cancer test

A good cancer test needs to be suitable to use in entire populations of people who are likely healthy. If getting tested is a nasty experience, then no one is going to choose to do it.

“If you’re going to test people without symptoms, the test needs to be acceptable,” says Pharoah.

Sensitivity

A sensitive test picks out cancer when it’s there so fewer cancers are missed (false negatives).

Specificity

A specific test doesn’t pick up something else and say it’s cancer by mistake (false positives).

The sample that you’re looking for cancer in must also be readily available. “That could be blood, urine, faeces. Basically, anything that you can find evidence of cancer in and acquire easily.”

It also needs to be reliable, so it doesn’t lead doctors on a wild-goose chase.

“The test needs to be fairly sensitive, because you want it to be able to pick up most of the people who’ve got the cancer,” says Pharoah.

But you also need to be confident that the positive results are correct, so doctors don’t follow the wrong lines of investigation with too many people.

“It needs to be reasonably specific so that if the test is positive it’s not detecting all sorts of other conditions.”

Lastly, useful cancer tests must be cheap so it can be used on thousands of people without financially crippling healthcare providers.

Why haven’t more cancer tests been developed?

Despite Pharoah saying that a screening test “doesn’t have to be perfect” because it’s not designed to diagnose someone with cancer, but rather highlight those who may need more investigation, even getting to the stage where a test works fairly well is troublesome. As it turns out, finding the perfect ‘red flag’ or marker of cancer for the test to pick up is incredibly hard.

Pharoah says researchers have spent a considerable amount of time following promising but ultimately unsuccessful leads – molecules that at first seem to be a good indicator of cancer but, after more research, turn out to be unsuitable. Often this is because the molecules aren’t just made by the tumour, they’re also produced by healthy cells. Or they’re made in too small quantities for a cancer test to detect.

And once you’ve found a suitable cancer ‘red flag’, you need to make sure it’s fit for purpose. The next step is often to use the test on people who already have cancer, where there are likely to be a lot more ‘red flag’ molecules floating around. It’s a sensible start – if a test can’t pick up cancer that’s already been diagnosed then it’s unlikely to be able to detect smaller cancers – but positive results at this stage aren’t as ‘game-changing’ as many headlines suggest.

For a test to really work, it needs to pick up tiny amounts of disease in people who don’t even know they have it.

“To show that screening with a given test is a useful intervention you need to do a randomised control trial.” These trials are very costly and difficult to organise because they need to include very large numbers of people.

Overcoming overdiagnosis

Finally, when you go looking for something you can usually find it. With every cancer test you also run the risk of identifying tiny tumours that may not have gone on to cause harm. We have not yet developed a way to distinguish between cancers that are dangerous and need treatment, and those which aren’t and could be safely left alone.

“There are lots of cancers that are called ‘cancer’ if you look at them under the microscope but actually, they were never destined to kill that person because they’re slow growing,” says Pharaoh.

And so naturally some of these cancers are treated, which could lead to unnecessary side effects.

Research to clear muddied waters

There are currently three national cancer screening programmes available in the UK for cervical, breast and bowel cancers. But, due to difficulties in developing useful cancer tests, these life-saving programmes have been decades in the making.

False clues make detecting cancer at an early stage very hard. But thanks to research, scientists are getting better at identifying red herrings. And learning more about cancer biology will get us closer to knowing how to set dangerous cancers apart from the mass of other molecules clouding our bodily fluids.

Although hard work, early detection is an investment that will really pay off. Developing these types of tests which meet the criteria above and promptly putting them into practice, will give people the best possible chance of treatment being successful and maybe even cure.

Follow our series to find out all the different ways – and types of bodily fluid – our scientists are investigating to find cancer early and boost the number of people who survive.

Gabi

from Cancer Research UK – Science blog https://ift.tt/34YuZCt

The earlier a cancer is picked up, the more likely a person is to survive. And if we can’t stop cancers starting then, detecting them before they cause trouble is the next best thing.

But detecting the almost undetectable comes with significant challenges as these tiny, newly formed cancers are hiding from scientists and doctors amongst a smokescreen of trillions of healthy cells.

Detecting the almost undetectable

To find cancer in the body, first you need something to look for.

A successful cancer test will be able to detect ‘red-flag’ molecules produced by the cancer, revealing its presence. And to pick up disease at a stage where it can be cured with treatment such as surgery, the cancer needs to be compact and contained. Unfortunately, in most cases, this means it’s small enough to lay low. So, to locate these tiny cancers and successfully pick up the small number of ‘red flag’ molecules they’re making, scientists have to get creative.

One type of test that’s seen a lot of investment are those looking for floating bits of cancer cell DNA in the blood.

Professor Paul Pharoah, from the Cancer Research UK Cambridge Centre, says “a very small part of the blood is made up of cell free DNA that’s come from all sorts of places in your body.” Cancer cells can also release DNA into the bloodstream when they die, which could be picked up by testing the blood. But it’s no mean feat.

“The proportion of DNA from cancer is even smaller and therefore your test has to be incredibly sensitive to look beyond all of these extra DNA pieces,” says Pharoah, adding that urine, poo and breath may also contain signs of cancer.

The secret to a good cancer test

A good cancer test needs to be suitable to use in entire populations of people who are likely healthy. If getting tested is a nasty experience, then no one is going to choose to do it.

“If you’re going to test people without symptoms, the test needs to be acceptable,” says Pharoah.

Sensitivity

A sensitive test picks out cancer when it’s there so fewer cancers are missed (false negatives).

Specificity

A specific test doesn’t pick up something else and say it’s cancer by mistake (false positives).

The sample that you’re looking for cancer in must also be readily available. “That could be blood, urine, faeces. Basically, anything that you can find evidence of cancer in and acquire easily.”

It also needs to be reliable, so it doesn’t lead doctors on a wild-goose chase.

“The test needs to be fairly sensitive, because you want it to be able to pick up most of the people who’ve got the cancer,” says Pharoah.

But you also need to be confident that the positive results are correct, so doctors don’t follow the wrong lines of investigation with too many people.

“It needs to be reasonably specific so that if the test is positive it’s not detecting all sorts of other conditions.”

Lastly, useful cancer tests must be cheap so it can be used on thousands of people without financially crippling healthcare providers.

Why haven’t more cancer tests been developed?

Despite Pharoah saying that a screening test “doesn’t have to be perfect” because it’s not designed to diagnose someone with cancer, but rather highlight those who may need more investigation, even getting to the stage where a test works fairly well is troublesome. As it turns out, finding the perfect ‘red flag’ or marker of cancer for the test to pick up is incredibly hard.

Pharoah says researchers have spent a considerable amount of time following promising but ultimately unsuccessful leads – molecules that at first seem to be a good indicator of cancer but, after more research, turn out to be unsuitable. Often this is because the molecules aren’t just made by the tumour, they’re also produced by healthy cells. Or they’re made in too small quantities for a cancer test to detect.

And once you’ve found a suitable cancer ‘red flag’, you need to make sure it’s fit for purpose. The next step is often to use the test on people who already have cancer, where there are likely to be a lot more ‘red flag’ molecules floating around. It’s a sensible start – if a test can’t pick up cancer that’s already been diagnosed then it’s unlikely to be able to detect smaller cancers – but positive results at this stage aren’t as ‘game-changing’ as many headlines suggest.

For a test to really work, it needs to pick up tiny amounts of disease in people who don’t even know they have it.

“To show that screening with a given test is a useful intervention you need to do a randomised control trial.” These trials are very costly and difficult to organise because they need to include very large numbers of people.

Overcoming overdiagnosis

Finally, when you go looking for something you can usually find it. With every cancer test you also run the risk of identifying tiny tumours that may not have gone on to cause harm. We have not yet developed a way to distinguish between cancers that are dangerous and need treatment, and those which aren’t and could be safely left alone.

“There are lots of cancers that are called ‘cancer’ if you look at them under the microscope but actually, they were never destined to kill that person because they’re slow growing,” says Pharaoh.

And so naturally some of these cancers are treated, which could lead to unnecessary side effects.

Research to clear muddied waters

There are currently three national cancer screening programmes available in the UK for cervical, breast and bowel cancers. But, due to difficulties in developing useful cancer tests, these life-saving programmes have been decades in the making.

False clues make detecting cancer at an early stage very hard. But thanks to research, scientists are getting better at identifying red herrings. And learning more about cancer biology will get us closer to knowing how to set dangerous cancers apart from the mass of other molecules clouding our bodily fluids.

Although hard work, early detection is an investment that will really pay off. Developing these types of tests which meet the criteria above and promptly putting them into practice, will give people the best possible chance of treatment being successful and maybe even cure.

Follow our series to find out all the different ways – and types of bodily fluid – our scientists are investigating to find cancer early and boost the number of people who survive.

Gabi

from Cancer Research UK – Science blog https://ift.tt/34YuZCt

Aldebaran is star near moon on November 13

On November 13, 2019, the waning gibbous moon passes to the north of Aldebaran, an ex-pole star, a famous zodiac star and the brightest star in the constellation Taurus the Bull.

This is a wonderful time to learn to identify this star, even though you might have to squint a bit to see it in the glare of tonight’s moon. These two luminaries should be up by nightfall or early evening. If you can see the moon, but not Aldebaran, try placing your finger over the moon to seek out

Aldebaran is a bright reddish star, a good star to come to know. Did you know that Aldebaran is also a former pole star? It’s true, and it’s a fascinating story.

Many people know that Polaris is the present-day North Star, but few know that Aldebaran reigned as the North Star some 450,000 years ago.

What’s more, Aldebaran appeared several times brighter in the sky then than it does now. Plus – 450,000 years ago – Aldebaran shone very close to the very bright star Capella on the sky’s dome. In that distant past, these two brilliant stars served as a double pole star in the astronomical year -447,890 (447,891 B.C.).

View larger. | This illustration shows the view from present-day Arizona in 447,000 B.C., when Aldebaran and Capella served as double pole stars. Image via Carina Software and Instruments.

At this point, we should probably insert a note about astronomical dating. In ancient times, there was no zero year, so the year A.D. 1 followed the year 1 B.C. However, present-day astronomical calculating is made simpler by equating the astronomical year 0 with the year 1 B.C. Thus, the astronomical year -1 corresponds to 2 B.C. and the astronomical year -2 corresponds to 3 B.C. And so on …

But back to Aldebaran and Capella as dual pole stars. The identity of the pole star shifts over time, due to the 26,000-year cycle of precession. To read more about that, click into this article about Thuban, another former pole star.

Still, how can it be, you might wonder, that the stars Aldebaran and Capella were once so near each other on the sky’s dome? They’re not especially close together now. Aren’t the stars essentially fixed relative to one another? The answer is that, yes, on the scale of a human lifespan, the stars are essentially fixed. But the stars are actually moving through space, in orbit around the center of the galaxy. In our solar system, galaxy, and universe … everything is always moving. So the sky looked different hundreds of thousands of years ago than it does today.

So watch for Aldebaran near the moon tonight, and think back to 450,000 years ago, when Aldebaran and Capella teamed up together to serve as Earth’s double north pole star!*

*Source: Page 363 of Mathematical Astronomy Morsels V by Jean Meeus

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Bottom line: Will you see the red star Aldebaran – Eye of the Bull in Taurus – in the moon’s glare tonight? More here, including the story of Aldebaran when it joined with another bright star, Capella, to appear as a double pole star.

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On November 13, 2019, the waning gibbous moon passes to the north of Aldebaran, an ex-pole star, a famous zodiac star and the brightest star in the constellation Taurus the Bull.

This is a wonderful time to learn to identify this star, even though you might have to squint a bit to see it in the glare of tonight’s moon. These two luminaries should be up by nightfall or early evening. If you can see the moon, but not Aldebaran, try placing your finger over the moon to seek out

Aldebaran is a bright reddish star, a good star to come to know. Did you know that Aldebaran is also a former pole star? It’s true, and it’s a fascinating story.

Many people know that Polaris is the present-day North Star, but few know that Aldebaran reigned as the North Star some 450,000 years ago.

What’s more, Aldebaran appeared several times brighter in the sky then than it does now. Plus – 450,000 years ago – Aldebaran shone very close to the very bright star Capella on the sky’s dome. In that distant past, these two brilliant stars served as a double pole star in the astronomical year -447,890 (447,891 B.C.).

View larger. | This illustration shows the view from present-day Arizona in 447,000 B.C., when Aldebaran and Capella served as double pole stars. Image via Carina Software and Instruments.

At this point, we should probably insert a note about astronomical dating. In ancient times, there was no zero year, so the year A.D. 1 followed the year 1 B.C. However, present-day astronomical calculating is made simpler by equating the astronomical year 0 with the year 1 B.C. Thus, the astronomical year -1 corresponds to 2 B.C. and the astronomical year -2 corresponds to 3 B.C. And so on …

But back to Aldebaran and Capella as dual pole stars. The identity of the pole star shifts over time, due to the 26,000-year cycle of precession. To read more about that, click into this article about Thuban, another former pole star.

Still, how can it be, you might wonder, that the stars Aldebaran and Capella were once so near each other on the sky’s dome? They’re not especially close together now. Aren’t the stars essentially fixed relative to one another? The answer is that, yes, on the scale of a human lifespan, the stars are essentially fixed. But the stars are actually moving through space, in orbit around the center of the galaxy. In our solar system, galaxy, and universe … everything is always moving. So the sky looked different hundreds of thousands of years ago than it does today.

So watch for Aldebaran near the moon tonight, and think back to 450,000 years ago, when Aldebaran and Capella teamed up together to serve as Earth’s double north pole star!*

*Source: Page 363 of Mathematical Astronomy Morsels V by Jean Meeus

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

Bottom line: Will you see the red star Aldebaran – Eye of the Bull in Taurus – in the moon’s glare tonight? More here, including the story of Aldebaran when it joined with another bright star, Capella, to appear as a double pole star.

from EarthSky https://ift.tt/2rxF6j9

SDO caught Monday’s Mercury transit from space

NASA’s Solar Dynamics Observatory (SDO) had a ringside seat on Monday, November 11, 2019, watched as Mercury crossed the face of the sun, in the last transit of Mercury until the year 2032. The video above shows SDO’s views of the sun – during the hours of the transit – in a variety of wavelengths of light in the extreme ultraviolet.

Plus … hey, who knew NASA could be funny?

Q: What did Mercury say when it was asked to line up between Earth & the Sun?
A: I'll pass! ?

We witnessed a rare treat during today's #MercuryTransit, which only happens ~13 times a century! Revel in the views captured our @NASASun-observing satellite: https://t.co/Wm7TYlNSeX pic.twitter.com/UqhYHTpAQm

— NASA (@NASA) November 12, 2019

Bottom line: Video of November 11, 2019 transit of Mercury, as seen by NASA’s Solar Dynamics Observatory.

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NASA’s Solar Dynamics Observatory (SDO) had a ringside seat on Monday, November 11, 2019, watched as Mercury crossed the face of the sun, in the last transit of Mercury until the year 2032. The video above shows SDO’s views of the sun – during the hours of the transit – in a variety of wavelengths of light in the extreme ultraviolet.

Plus … hey, who knew NASA could be funny?

Q: What did Mercury say when it was asked to line up between Earth & the Sun?
A: I'll pass! ?

We witnessed a rare treat during today's #MercuryTransit, which only happens ~13 times a century! Revel in the views captured our @NASASun-observing satellite: https://t.co/Wm7TYlNSeX pic.twitter.com/UqhYHTpAQm

— NASA (@NASA) November 12, 2019

Bottom line: Video of November 11, 2019 transit of Mercury, as seen by NASA’s Solar Dynamics Observatory.

from EarthSky https://ift.tt/34Sn21G

Some microbes eat electricity

Scientists have discovered that there are certain microbes that find electricity very tasty. What’s more, it turns out that these electron-eating microbes are very common. Scientists are finding them in many different places.

But how to these microbes do it? Microbes – microscopic organisms such as bacteria, protozoa, fungi – don’t have mouths, so they need another way to bring their fuel into their bodies. A new study, published November 5, 2019 in the journal mBio reveals how one such bacteria pulls in electrons straight from an electrode source.

Washington University biologist Arpita Bose is a coauthor of the study. She said in a statement:

The molecular underpinning of this process has been difficult to unravel … This is mostly due to the complex nature of the proteins involved in this process.

According to the researchers, getting the electricity across the outer layer of the bacteria is the key challenge. This barrier is both nonconductive and impermeable to insoluble iron minerals and/or electrodes.

R. palustris TIE-1 builds a conduit to accept electrons across its outer membrane. Image via Bose laboratory.

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The study scientists showed that the naturally occurring strain of a bacteria called Rhodopseudomonas palustris TIE-1 builds a conduit to accept electrons across its outer membrane. According the the research, the bacteria relies on an iron-containing helper molecule called a deca-heme cytochrome c. By processing this protein, TIE-1 can form an essential bridge to its electron source.

The ability of these microbes to take up electrons from substances such as metal oxides – called extracellular electron uptake – can help microbes to survive under nutrient-scarce conditions.

Dinesh Gupta, a PhD candidate at Washington University, is the study lead author. Gupta said:

This study will aid in designing a bacterial platform where bacteria can feed on electricity and carbon dioxide to produce value-added compounds such as biofuels.

Source: Photoferrotrophs Produce a PioAB Electron Conduit for Extracellular Electron Uptake

Via Washington University

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Scientists have discovered that there are certain microbes that find electricity very tasty. What’s more, it turns out that these electron-eating microbes are very common. Scientists are finding them in many different places.

But how to these microbes do it? Microbes – microscopic organisms such as bacteria, protozoa, fungi – don’t have mouths, so they need another way to bring their fuel into their bodies. A new study, published November 5, 2019 in the journal mBio reveals how one such bacteria pulls in electrons straight from an electrode source.

Washington University biologist Arpita Bose is a coauthor of the study. She said in a statement:

The molecular underpinning of this process has been difficult to unravel … This is mostly due to the complex nature of the proteins involved in this process.

According to the researchers, getting the electricity across the outer layer of the bacteria is the key challenge. This barrier is both nonconductive and impermeable to insoluble iron minerals and/or electrodes.

R. palustris TIE-1 builds a conduit to accept electrons across its outer membrane. Image via Bose laboratory.

EarthSky’s 2020 lunar calendars are here! Get yours today. They make great gifts. Going fast.

The study scientists showed that the naturally occurring strain of a bacteria called Rhodopseudomonas palustris TIE-1 builds a conduit to accept electrons across its outer membrane. According the the research, the bacteria relies on an iron-containing helper molecule called a deca-heme cytochrome c. By processing this protein, TIE-1 can form an essential bridge to its electron source.

The ability of these microbes to take up electrons from substances such as metal oxides – called extracellular electron uptake – can help microbes to survive under nutrient-scarce conditions.

Dinesh Gupta, a PhD candidate at Washington University, is the study lead author. Gupta said:

This study will aid in designing a bacterial platform where bacteria can feed on electricity and carbon dioxide to produce value-added compounds such as biofuels.

Source: Photoferrotrophs Produce a PioAB Electron Conduit for Extracellular Electron Uptake

Via Washington University

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

See it! Monday’s transit of Mercury

You’ll find even more images at EarthSky Community Photos. A huge thank you to all who submitted! Submit your Earth and sky photos here.

View at EarthSky Community Photos. https://ift.tt/2ND7Aki | Karl Diefenderfer wrote: “The clouds were threatening but held off until I was able to snap a few photos.”

View at EarthSky Community Photos. https://ift.tt/2X7GAwv | Steve Scanlon https://ift.tt/2pV9804 in Long Branch, New Jersey wrote: “Crossed fingers for clear skies prevailed.”

View at EarthSky Community Photos.https://ift.tt/34UATEQ | Joel Weatherly https://ift.tt/2QbbS48 in Edmonton, Alberta, Canada wrote: “I enjoyed watching and photographing this morning’s Transit of Mercury. While I missed the first bit in Edmonton, the skies were very clear (some atmospheric turbulence though). Here’s my shot at capturing the event, I finally got to give my Calcium K-line filter a go.”

View at EarthSky Community Photos. https://ift.tt/36W0b7g | Tom Palmer of Carrboro, North Carolina wrote: “This was taken at 1:02:54 pm ET, just a few seconds after 3rd contact, when the disk of Mercury had just started exiting the face of the sun.”

View at EarthSky Community Photos.https://ift.tt/36STeUl | Mimi Ditchie https://ift.tt/2KegLWl at Avila Beach, California worte: “This is an image of Mercury transiting the sun. Mercury is the small black dot in the mid-upper right of the sun.”

View at EarthSky Community Photos. https://ift.tt/2X8z5Ff | Chirag Upreti in New York, New York wrote: “We had brief clear skies over NYC during the start of the Mercury transit, later high clouds rolled in making Mercury hard to spot through the haze. I was amazed at the scale of this speedy little planet compared to our star, it gave a wonderful perspective.”

View at EarthSky Community Photos. https://ift.tt/2NDXz6a | Richard Lakhan https://ift.tt/2X6pa31 in Trinidad wrote: “Transit of Mercury – view from Trinidad.” Thanks, Richard!

View at EarthSky Community Photos. https://ift.tt/32CDTE7 | Ken Gallagher https://ift.tt/2Qbfp24 at Lake Havasu City, Arizona wrote: “Was hoping for some sun spots.”

View at EarthSky Community Photos. https://ift.tt/36VDUq7 | Tom Wildoner at the The Dark Side Observatory https://ift.tt/2Dc1IYf in Weatherly, Pennsylvania wrote: “Here is a view of the Mercury transit across the sun.”

View at EarthSky Community Photos. https://ift.tt/2NEha6t | Steve Bellavia of Southold, New York captured this image.

View at EarthSky Community Photos. https://ift.tt/2X8uza8 | Olivér Nagy in Budapest wrote: “I was at my workplace, but I take one day off. I have pack out at the roof of our office, to follow up the Mercury transit. From Budapest, it was visible from start till the center point. I used 2 telescopes,one for visual, where I could show my colleges the transit, and one for photography. Unfortunately, awe received some clouds, and I was only able to take good images from the beginning, and some during sunset including this one, where the Mercury is almost at the center of the sun.”

View at EarthSky Community Photos. https://earthsky.org/earthsky-community-photos/entry/21397| Ken Chan in Palo Alto, California wrote: “It had been foggy in the morning for the past few days. Fortunately, it was clear this morning, and I was able to see Mercury transit the sun.” Thanks, Ken!

View at EarthSky Community Photos. https://ift.tt/2O4JaPx | Jean Marie André Delaporte https://ift.tt/29yahkM of Normandy, France wrote: “Here you go, the splendid transit of Mercury in front of the sun. I’m so happy.”

View at EarthSky Community Photos. https://ift.tt/36YoJfK | Eric Smith https://www.facebook.com/profile.php?id=1453217299&__tn__=%2Cd*F*F-R&eid=ARBO_j0czHRO4aBsXsWmEh6YY2qIrRgexzm7UceZ5d9ZaiEl2mGE9SMtwZAKdU3jTou8Oiv_sxW1ZZEH&tn-str=*F at Paso Robles, California wrote: “A fitting tribute to Veterans Day was today’s transit of the sun by the planet Mercury! Enjoy, Fellow Star Voyagers!”

View at EarthSky Community Photos. https://ift.tt/36WMFA6 | Eliot Herman https://ift.tt/2O4ErNW wrote: “In Tucson, Arizona, seeing was mostly fair to poor. At sunrise there were thick clouds that disappeared for a nice window after mid-transit when this photo was captured and then more haze and light clouds for toward the end of the transit. This photo was at about best seeing conditions.”

View at EarthSky Community Photos. https://ift.tt/2O7gntN | Annie Lewis https://www.facebook.com/Annie.Lewis2212?__tn__=%2CdC-R-R&eid=ARDXsp9iKNOgz64Y4qEX4cI_vwbegxzH1PGCAG24yY3AWqs4-22fjL_87eVeeoh3R2nPFUrt7AyAHZZx&hc_ref=ARSFv5sVwSw6qdXr_q92vsYe3EO7KS56e8TeQcMNWYKmQsjEbngVuFC3fwtyCteE6sk&fref=nf wrote: “Awful cloudy day here in Madrid, Spain, but I’ve just about managed to get Mercury entering the sun’s disk.”

View at EarthSky Community Photos.https://ift.tt/33FMJlW | Abdulmajeed Alshatti https://ift.tt/2O71KGD in Kuwait wrote: “Mercury in a rare pass across the Sun today. This is photo shows the position of Mercury after 1 hour and 10 minutes after the starting the transition in Kuwait, at sunset.”

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You’ll find even more images at EarthSky Community Photos. A huge thank you to all who submitted! Submit your Earth and sky photos here.

View at EarthSky Community Photos. https://ift.tt/2ND7Aki | Karl Diefenderfer wrote: “The clouds were threatening but held off until I was able to snap a few photos.”

View at EarthSky Community Photos. https://ift.tt/2X7GAwv | Steve Scanlon https://ift.tt/2pV9804 in Long Branch, New Jersey wrote: “Crossed fingers for clear skies prevailed.”

View at EarthSky Community Photos.https://ift.tt/34UATEQ | Joel Weatherly https://ift.tt/2QbbS48 in Edmonton, Alberta, Canada wrote: “I enjoyed watching and photographing this morning’s Transit of Mercury. While I missed the first bit in Edmonton, the skies were very clear (some atmospheric turbulence though). Here’s my shot at capturing the event, I finally got to give my Calcium K-line filter a go.”

View at EarthSky Community Photos. https://ift.tt/36W0b7g | Tom Palmer of Carrboro, North Carolina wrote: “This was taken at 1:02:54 pm ET, just a few seconds after 3rd contact, when the disk of Mercury had just started exiting the face of the sun.”

View at EarthSky Community Photos.https://ift.tt/36STeUl | Mimi Ditchie https://ift.tt/2KegLWl at Avila Beach, California worte: “This is an image of Mercury transiting the sun. Mercury is the small black dot in the mid-upper right of the sun.”

View at EarthSky Community Photos. https://ift.tt/2X8z5Ff | Chirag Upreti in New York, New York wrote: “We had brief clear skies over NYC during the start of the Mercury transit, later high clouds rolled in making Mercury hard to spot through the haze. I was amazed at the scale of this speedy little planet compared to our star, it gave a wonderful perspective.”

View at EarthSky Community Photos. https://ift.tt/2NDXz6a | Richard Lakhan https://ift.tt/2X6pa31 in Trinidad wrote: “Transit of Mercury – view from Trinidad.” Thanks, Richard!

View at EarthSky Community Photos. https://ift.tt/32CDTE7 | Ken Gallagher https://ift.tt/2Qbfp24 at Lake Havasu City, Arizona wrote: “Was hoping for some sun spots.”

View at EarthSky Community Photos. https://ift.tt/36VDUq7 | Tom Wildoner at the The Dark Side Observatory https://ift.tt/2Dc1IYf in Weatherly, Pennsylvania wrote: “Here is a view of the Mercury transit across the sun.”

View at EarthSky Community Photos. https://ift.tt/2NEha6t | Steve Bellavia of Southold, New York captured this image.

View at EarthSky Community Photos. https://ift.tt/2X8uza8 | Olivér Nagy in Budapest wrote: “I was at my workplace, but I take one day off. I have pack out at the roof of our office, to follow up the Mercury transit. From Budapest, it was visible from start till the center point. I used 2 telescopes,one for visual, where I could show my colleges the transit, and one for photography. Unfortunately, awe received some clouds, and I was only able to take good images from the beginning, and some during sunset including this one, where the Mercury is almost at the center of the sun.”

View at EarthSky Community Photos. https://earthsky.org/earthsky-community-photos/entry/21397| Ken Chan in Palo Alto, California wrote: “It had been foggy in the morning for the past few days. Fortunately, it was clear this morning, and I was able to see Mercury transit the sun.” Thanks, Ken!

View at EarthSky Community Photos. https://ift.tt/2O4JaPx | Jean Marie André Delaporte https://ift.tt/29yahkM of Normandy, France wrote: “Here you go, the splendid transit of Mercury in front of the sun. I’m so happy.”

View at EarthSky Community Photos. https://ift.tt/36YoJfK | Eric Smith https://www.facebook.com/profile.php?id=1453217299&__tn__=%2Cd*F*F-R&eid=ARBO_j0czHRO4aBsXsWmEh6YY2qIrRgexzm7UceZ5d9ZaiEl2mGE9SMtwZAKdU3jTou8Oiv_sxW1ZZEH&tn-str=*F at Paso Robles, California wrote: “A fitting tribute to Veterans Day was today’s transit of the sun by the planet Mercury! Enjoy, Fellow Star Voyagers!”

View at EarthSky Community Photos. https://ift.tt/36WMFA6 | Eliot Herman https://ift.tt/2O4ErNW wrote: “In Tucson, Arizona, seeing was mostly fair to poor. At sunrise there were thick clouds that disappeared for a nice window after mid-transit when this photo was captured and then more haze and light clouds for toward the end of the transit. This photo was at about best seeing conditions.”

View at EarthSky Community Photos. https://ift.tt/2O7gntN | Annie Lewis https://www.facebook.com/Annie.Lewis2212?__tn__=%2CdC-R-R&eid=ARDXsp9iKNOgz64Y4qEX4cI_vwbegxzH1PGCAG24yY3AWqs4-22fjL_87eVeeoh3R2nPFUrt7AyAHZZx&hc_ref=ARSFv5sVwSw6qdXr_q92vsYe3EO7KS56e8TeQcMNWYKmQsjEbngVuFC3fwtyCteE6sk&fref=nf wrote: “Awful cloudy day here in Madrid, Spain, but I’ve just about managed to get Mercury entering the sun’s disk.”

View at EarthSky Community Photos.https://ift.tt/33FMJlW | Abdulmajeed Alshatti https://ift.tt/2O71KGD in Kuwait wrote: “Mercury in a rare pass across the Sun today. This is photo shows the position of Mercury after 1 hour and 10 minutes after the starting the transition in Kuwait, at sunset.”

from EarthSky https://ift.tt/2p9ICPY