Watch for Jupiter, Saturn and the moon

To see Jupiter and Saturn now, look outside from late night – when you’ll find them ascending in the east – until dawn. The late night on June 7, 2020 or early morning on June 8 are grand opportunities to identify them as the moon sweeps by. This chart shows the sky from 40 degrees N. latitude, 3-and-a-half hours after sunset. For your specific view, or a different time of night, try Stellarium. Chart via Guy Ottewell’s blog.

Originally printed at Guy Ottewell’s blog, Universal Workshop. Re-printed here with permission.

As Jupiter continues to catch up with Saturn – preparing for their once-in-20-years great conjunction in December 2020 – the waning moon comes by, this time passing 2.2° south of Jupiter on June 8 and 2.7° south of Saturn on June 9.

Those angular separations – or apparent separations on or sky’s dome – refer to the center of the moon; from our northern latitudes, the moon is pushed a bit south.

In my picture at top, the moon (at twice its real size) is where it is seen from the chosen U.S. location; but the arrows connecting moon positions are along the track it would take if viewed from the center of the Earth. The difference is the effect called parallax, an effect you can experience yourself when when you hold a finger in front of your nose, but look into the distance (you see two fingers, separated by parallax).

The grouping of the three luminaries – Jupiter, Saturn and the moon – will be tightest at 22h UTC, 17 hours after the time of the picture and in daylight for America. The planets and the moon’s center get to be within a circle of diameter 5.06 degrees, though that is as seen from Earth’s center (parallax makes it a bit wider).

For Saturn, we show its disk, exaggerated 150 times in size, so as to show the current attitude of its rings (their north face is open toward us).

On June 7, the moon will be two days past full, so the planets will be twinkles within its glare. The magnitudes of the moon, Jupiter, and Saturn are -12, -3, and 0.

As the night goes on, the scene will slant up to higher in the sky. And then, if your sky is clear and dark, the Milky Way will become visible.

But not Pluto! Notice it on the chart at top. Pluto is more than 1,000 times too faint to be viewed with the eye. Yet telescopic observers can use Jupiter to find Pluto this year. Read more: Jupiter gives us Pluto in 2020

Now note the area marked as solstice point on the chart at top. That is where the sun is at mid-winter, at its most southerly point on the ecliptic. These planets, and the moon when opposite to the summer sun, are nearly as far south as they can be in the sky.

The anti-sun, as I call it, is also not something that can be seen, except at a lunar eclipse, when Earth’s shadow becomes visible on the moon; but it is an interesting point to contemplate. See it on the chart at top? When at or near it, the moon is full and a planet is at opposition, or most nearly opposite the sun from Earth for that year. It divides the evening sky, to the right of it, from the morning sky, to the left.

Thus, by staying up late, you get a look into the morning sky, of which Jupiter and Saturn are the heralds.

Bottom line: Watch for the moon, Jupiter and Saturn around June 7, 2020. The moon is very bright now, so Jupiter and Saturn are specks in its glare. Jupiter is a brighter speck than Saturn.

Read more: Before 2020 ends, a great conjunction of Jupiter and Saturn

from EarthSky https://ift.tt/3dGzkPo

To see Jupiter and Saturn now, look outside from late night – when you’ll find them ascending in the east – until dawn. The late night on June 7, 2020 or early morning on June 8 are grand opportunities to identify them as the moon sweeps by. This chart shows the sky from 40 degrees N. latitude, 3-and-a-half hours after sunset. For your specific view, or a different time of night, try Stellarium. Chart via Guy Ottewell’s blog.

Originally printed at Guy Ottewell’s blog, Universal Workshop. Re-printed here with permission.

As Jupiter continues to catch up with Saturn – preparing for their once-in-20-years great conjunction in December 2020 – the waning moon comes by, this time passing 2.2° south of Jupiter on June 8 and 2.7° south of Saturn on June 9.

Those angular separations – or apparent separations on or sky’s dome – refer to the center of the moon; from our northern latitudes, the moon is pushed a bit south.

In my picture at top, the moon (at twice its real size) is where it is seen from the chosen U.S. location; but the arrows connecting moon positions are along the track it would take if viewed from the center of the Earth. The difference is the effect called parallax, an effect you can experience yourself when when you hold a finger in front of your nose, but look into the distance (you see two fingers, separated by parallax).

The grouping of the three luminaries – Jupiter, Saturn and the moon – will be tightest at 22h UTC, 17 hours after the time of the picture and in daylight for America. The planets and the moon’s center get to be within a circle of diameter 5.06 degrees, though that is as seen from Earth’s center (parallax makes it a bit wider).

For Saturn, we show its disk, exaggerated 150 times in size, so as to show the current attitude of its rings (their north face is open toward us).

On June 7, the moon will be two days past full, so the planets will be twinkles within its glare. The magnitudes of the moon, Jupiter, and Saturn are -12, -3, and 0.

As the night goes on, the scene will slant up to higher in the sky. And then, if your sky is clear and dark, the Milky Way will become visible.

But not Pluto! Notice it on the chart at top. Pluto is more than 1,000 times too faint to be viewed with the eye. Yet telescopic observers can use Jupiter to find Pluto this year. Read more: Jupiter gives us Pluto in 2020

Now note the area marked as solstice point on the chart at top. That is where the sun is at mid-winter, at its most southerly point on the ecliptic. These planets, and the moon when opposite to the summer sun, are nearly as far south as they can be in the sky.

The anti-sun, as I call it, is also not something that can be seen, except at a lunar eclipse, when Earth’s shadow becomes visible on the moon; but it is an interesting point to contemplate. See it on the chart at top? When at or near it, the moon is full and a planet is at opposition, or most nearly opposite the sun from Earth for that year. It divides the evening sky, to the right of it, from the morning sky, to the left.

Thus, by staying up late, you get a look into the morning sky, of which Jupiter and Saturn are the heralds.

Bottom line: Watch for the moon, Jupiter and Saturn around June 7, 2020. The moon is very bright now, so Jupiter and Saturn are specks in its glare. Jupiter is a brighter speck than Saturn.

Read more: Before 2020 ends, a great conjunction of Jupiter and Saturn

from EarthSky https://ift.tt/3dGzkPo

Jupiter, Saturn, moon on June 6-8, plus a word about the daytime moon

If you stay up late on the nights of June 6, 7 and 8, 2020, you can glimpse the moon with the bright planets Jupiter and Saturn, ascending in the east. Or see them before daybreak.

Among all the wonderful planet-viewing we’re having in 2020, Jupiter and Saturn hold their own, excitement-wise, by being near one another on the sky’s dome throughout this year. By 2020’s end, they’ll undergo a once-in-20-years great conjunction. This month, and for some months to come, Saturn will closely follow Jupiter westward across the sky. Watch for them in June from mid-to-late evening until dawn. Although Saturn is easily as bright as a 1st-magnitude star, the ringed planet pales next the the king planet Jupiter, which outshines Saturn by some 15 times.

Read more: Before 2020 ends, a great conjunction of Jupiter and Saturn

Try Stellarium for your specific view

After Jupiter and Saturn fade at sunup, look for a daytime moon to remain. No matter where you are on Earth, look generally westward after sunrise to see the moon in a blue daytime sky, assuming your sky is clear.

Are you an early riser? Then enjoy seeing the moon, Jupiter and Saturn higher up in the predawn/dawn sky. Although not visible, we show the dwarf planet Pluto because it’s close to Jupiter on the sky’s dome thruoghout the year 2020. Read more.

Why can you see the moon in the daytime now? The full moon – and partial penumbral eclipse – happened on the night of June 5-6, 2020, for the world’s Eastern Hemisphere. In the days after full moon, the moon is officially in a waning gibbous phase, rising in the east after nightfall and setting in a westward direction shortly after sunrise.

If you look for the moon at the same time every morning, you’ll see this week’s waning moon appearing higher and higher in the western sky each early morning, for several days. To understand why, think about where the sun is in early morning. A full moon is opposite the sun, in the west when the sun is in the east. Except now it’s after full moon. The moon is moving in its orbit around Earth – moving toward the east, as it always does – drawing closer and closer to the Earth-sun line.

By June 13, 2020, the moon will be at the last quarter phase – rising around midnight, southward around dawn. Then the moon will turn new on June 21, 2020, to showcase an annular eclipse of the sun. Two weeks after that, there will be a third eclipse – another penumbral eclipse of the moon – on the night of July 4-5. We won’t have three eclipses in one eclipse season again until the year 2029.

Read more: What is an eclipse season?

It still looks almost full, but the moon was just slightly past full. And so it was a waning gibbous moon that Peter Lowenstein caught on the morning of January 13, 2017 in Mutare, Zimbabwe.

People love to see the daytime moon. They wonder about it, and ask about it. Once, a reader in Kansas City wrote in with the name children’s moon to describe a moon visible during the day. She said this name stemmed from the idea that children can’t stay up at night late enough to see the moon when it appears only in darkness.

That story prompted another reader to send in an alternate version for the origin of the name children’s moon. She wrote:

I heard a daytime moon was called a ‘children’s moon’ because their eyes were sharp enough to pick it out, where the old folks, with fading vision, could not tell it from the clouds.

Can you see the daytime moon in the next few mornings?

July 29, 2018, daytime moon – caught from a rooftop in New York City – via our friend Ben Orlove.

Here’s another July daytime moon – from the year 2017 – from Jeff Hagan in Yakima, Washington. He wrote: “I woke up early and stepped onto the deck at our house in Yakima to check the weather. I was just in time to watch the full moon set over Mt. Adams, a 12,300-foot glaciated volcano in the Cascade Mountains. The moon appeared to be rolling down the north ridge of the mountain.”

Bottom line: If you stay up late on the nights of June 6, 7 and 8, 2020, you can glimpse the moon with the bright planets Jupiter and Saturn, ascending in the east. Or see them before daybreak.

A planisphere is virtually indispensable for beginning stargazers. Order your EarthSky planisphere today.

Four keys to understanding moon phases

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

If you stay up late on the nights of June 6, 7 and 8, 2020, you can glimpse the moon with the bright planets Jupiter and Saturn, ascending in the east. Or see them before daybreak.

Among all the wonderful planet-viewing we’re having in 2020, Jupiter and Saturn hold their own, excitement-wise, by being near one another on the sky’s dome throughout this year. By 2020’s end, they’ll undergo a once-in-20-years great conjunction. This month, and for some months to come, Saturn will closely follow Jupiter westward across the sky. Watch for them in June from mid-to-late evening until dawn. Although Saturn is easily as bright as a 1st-magnitude star, the ringed planet pales next the the king planet Jupiter, which outshines Saturn by some 15 times.

Read more: Before 2020 ends, a great conjunction of Jupiter and Saturn

Try Stellarium for your specific view

After Jupiter and Saturn fade at sunup, look for a daytime moon to remain. No matter where you are on Earth, look generally westward after sunrise to see the moon in a blue daytime sky, assuming your sky is clear.

Are you an early riser? Then enjoy seeing the moon, Jupiter and Saturn higher up in the predawn/dawn sky. Although not visible, we show the dwarf planet Pluto because it’s close to Jupiter on the sky’s dome thruoghout the year 2020. Read more.

Why can you see the moon in the daytime now? The full moon – and partial penumbral eclipse – happened on the night of June 5-6, 2020, for the world’s Eastern Hemisphere. In the days after full moon, the moon is officially in a waning gibbous phase, rising in the east after nightfall and setting in a westward direction shortly after sunrise.

If you look for the moon at the same time every morning, you’ll see this week’s waning moon appearing higher and higher in the western sky each early morning, for several days. To understand why, think about where the sun is in early morning. A full moon is opposite the sun, in the west when the sun is in the east. Except now it’s after full moon. The moon is moving in its orbit around Earth – moving toward the east, as it always does – drawing closer and closer to the Earth-sun line.

By June 13, 2020, the moon will be at the last quarter phase – rising around midnight, southward around dawn. Then the moon will turn new on June 21, 2020, to showcase an annular eclipse of the sun. Two weeks after that, there will be a third eclipse – another penumbral eclipse of the moon – on the night of July 4-5. We won’t have three eclipses in one eclipse season again until the year 2029.

Read more: What is an eclipse season?

It still looks almost full, but the moon was just slightly past full. And so it was a waning gibbous moon that Peter Lowenstein caught on the morning of January 13, 2017 in Mutare, Zimbabwe.

People love to see the daytime moon. They wonder about it, and ask about it. Once, a reader in Kansas City wrote in with the name children’s moon to describe a moon visible during the day. She said this name stemmed from the idea that children can’t stay up at night late enough to see the moon when it appears only in darkness.

That story prompted another reader to send in an alternate version for the origin of the name children’s moon. She wrote:

I heard a daytime moon was called a ‘children’s moon’ because their eyes were sharp enough to pick it out, where the old folks, with fading vision, could not tell it from the clouds.

Can you see the daytime moon in the next few mornings?

July 29, 2018, daytime moon – caught from a rooftop in New York City – via our friend Ben Orlove.

Here’s another July daytime moon – from the year 2017 – from Jeff Hagan in Yakima, Washington. He wrote: “I woke up early and stepped onto the deck at our house in Yakima to check the weather. I was just in time to watch the full moon set over Mt. Adams, a 12,300-foot glaciated volcano in the Cascade Mountains. The moon appeared to be rolling down the north ridge of the mountain.”

Bottom line: If you stay up late on the nights of June 6, 7 and 8, 2020, you can glimpse the moon with the bright planets Jupiter and Saturn, ascending in the east. Or see them before daybreak.

A planisphere is virtually indispensable for beginning stargazers. Order your EarthSky planisphere today.

Four keys to understanding moon phases

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

News digest – prostate cancer, COVID-19 trials, breast cancer genes and street lamps?

With news about the coronavirus pandemic developing daily, we want to make sure everyone affected by cancer gets the information they need during this time. 

We’re pulling together the latest government and NHS health updates from across the UK in a separate blog post, which we’re updating regularly. 

Prostate cancer most commonly diagnosed cancer in the UK

New analysis from Prostate Cancer UK suggests that prostate cancer has overtaken breast cancer as the most commonly diagnosed cancer in the UK. Though the numbers aren’t yet the full picture, the charity’s research finds that 57,192 new prostate cancer cases were diagnosed in the UK in 2018, just ahead of the 57,153 breast cancer cases that were diagnosed in the same year. The increasing number of new prostate cancer cases has been linked to increased awareness and earlier diagnosis. But more work is needed to develop tests that can differentiate between aggressive cancers and cancers that may never cause harm in an person’s lifetime. Find out more at The Guardian.

Prostate cancer blood test could help to tailor treatment 

Researchers at The Institute of Cancer Research (ICR) and The Royal Marsden NHS Foundation Trust have developed a new blood test that could help to predict how well patients with advanced prostate cancer will respond to treatment. The test could help clinicians to make more effective treatment decisions for people with advanced prostate cancer. The ICR and Royal Marsden are now looking to incorporate the test into other clinical trials to assess its benefits. Read more at Science Focus.

Cancer cells trigger inflammation to hide from viruses 

An international study led by a team at the Francis Crick Institute has helped researchers to understand why using viruses to kill cancer cells is only effective in a small number of people. The team found that a group of cells, known as cancer-associated fibroblasts (CAFs), cause inflammation in surrounding tissue when they come into contact with cancer cells. Researchers think this inflammation makes it difficult for cancer-killing viruses to enter cancer cells, limiting the effectiveness of virus-based cancer treatments. The team hopes that the study provides an ‘early step’ to improving the effectiveness of oncolytic virus treatments. Find out about the study at the Crick and News Atlas.

Repurposed drug tested for COVID-19, thanks to Cancer Research UK know-how 

Together with our partners, we’ve launched a clinical trial to test if a drug used to treat inflammation in the pancreas can treat people with COVID-19. With COVID-19 delaying cancer research and treatment, our researchers are using their expertise to help tackle the disease and get cancer services back on track, as our press release explains. 

Turning off a ‘key’ gene disrupts development and spread of triple-negative breast cancer in mice 

Researchers from Tulane University have found that ‘switching off’ a gene linked to triple triple negative breast cancer – TRAF3IP2 – can disrupt cancer growth and spread in mice. The researchers are now looking to get approval to start clinical trials . Read more about the discovery at Biospace. 

And finally…

Researchers at the National Cancer Institute in the United States have suggested that exposure to light at night from street lamps might be linked to an up to 10% increased risk of developing breast cancer after menopause. The study examined cases of breast cancer among 186,981 post-menopausal women over a 16-year period. Its findings suggest that women exposed to the highest levels of outdoor light at night had a ten percent higher chance of developing breast cancer during the follow up, compared to women with the lowest exposure. But despite the headlines, the findings don’t mean that street lamps cause breast cancer, and more research is needed to understand any connection. The Sun has this one.

Jamie Hamilton is a media and communication analyst at Cancer Research UK 

from Cancer Research UK – Science blog https://ift.tt/3f01chB

With news about the coronavirus pandemic developing daily, we want to make sure everyone affected by cancer gets the information they need during this time. 

We’re pulling together the latest government and NHS health updates from across the UK in a separate blog post, which we’re updating regularly. 

Prostate cancer most commonly diagnosed cancer in the UK

New analysis from Prostate Cancer UK suggests that prostate cancer has overtaken breast cancer as the most commonly diagnosed cancer in the UK. Though the numbers aren’t yet the full picture, the charity’s research finds that 57,192 new prostate cancer cases were diagnosed in the UK in 2018, just ahead of the 57,153 breast cancer cases that were diagnosed in the same year. The increasing number of new prostate cancer cases has been linked to increased awareness and earlier diagnosis. But more work is needed to develop tests that can differentiate between aggressive cancers and cancers that may never cause harm in an person’s lifetime. Find out more at The Guardian.

Prostate cancer blood test could help to tailor treatment 

Researchers at The Institute of Cancer Research (ICR) and The Royal Marsden NHS Foundation Trust have developed a new blood test that could help to predict how well patients with advanced prostate cancer will respond to treatment. The test could help clinicians to make more effective treatment decisions for people with advanced prostate cancer. The ICR and Royal Marsden are now looking to incorporate the test into other clinical trials to assess its benefits. Read more at Science Focus.

Cancer cells trigger inflammation to hide from viruses 

An international study led by a team at the Francis Crick Institute has helped researchers to understand why using viruses to kill cancer cells is only effective in a small number of people. The team found that a group of cells, known as cancer-associated fibroblasts (CAFs), cause inflammation in surrounding tissue when they come into contact with cancer cells. Researchers think this inflammation makes it difficult for cancer-killing viruses to enter cancer cells, limiting the effectiveness of virus-based cancer treatments. The team hopes that the study provides an ‘early step’ to improving the effectiveness of oncolytic virus treatments. Find out about the study at the Crick and News Atlas.

Repurposed drug tested for COVID-19, thanks to Cancer Research UK know-how 

Together with our partners, we’ve launched a clinical trial to test if a drug used to treat inflammation in the pancreas can treat people with COVID-19. With COVID-19 delaying cancer research and treatment, our researchers are using their expertise to help tackle the disease and get cancer services back on track, as our press release explains. 

Turning off a ‘key’ gene disrupts development and spread of triple-negative breast cancer in mice 

Researchers from Tulane University have found that ‘switching off’ a gene linked to triple triple negative breast cancer – TRAF3IP2 – can disrupt cancer growth and spread in mice. The researchers are now looking to get approval to start clinical trials . Read more about the discovery at Biospace. 

And finally…

Researchers at the National Cancer Institute in the United States have suggested that exposure to light at night from street lamps might be linked to an up to 10% increased risk of developing breast cancer after menopause. The study examined cases of breast cancer among 186,981 post-menopausal women over a 16-year period. Its findings suggest that women exposed to the highest levels of outdoor light at night had a ten percent higher chance of developing breast cancer during the follow up, compared to women with the lowest exposure. But despite the headlines, the findings don’t mean that street lamps cause breast cancer, and more research is needed to understand any connection. The Sun has this one.

Jamie Hamilton is a media and communication analyst at Cancer Research UK 

from Cancer Research UK – Science blog https://ift.tt/3f01chB

Did ancient Mars have rings?

Artist’s concept of the red planet Mars with rings. Image via Kevin Gill on Flickr/ CC by 2.0.

Ring systems are common in our solar system. Jupiter, Saturn, Uranus and Neptune all have rings. None of the smaller rocky planets have them, but is it possible that some of them could have had rings in the past? On June 2, 2020, scientists from the SETI Institute and Purdue University announced evidence suggesting that Mars used to have its own rings a few billion years ago. The findings would help explain why Mars’ smallest moon, Deimos, has an unusually tilted orbit.

The researchers published the new peer-reviewed paper in Astrophysical Journal Letters on June 1, 2020. The research was also presented at the 236th Meeting of the American Astronomical Society (AAS 236), held virtually this week (June 1-3, 2020) due to COVID-19.

While the orbits of both small moons, Phobos and Deimos, lie almost in the same plane as Mars’ equator – suggesting they formed at the same time as Mars – Deimos’ orbit is tilted by about 2 degrees. This tilt was an unusual and unexplained finding. It was also considered to be not all that significant in terms of Mars science.

Now it seems that, all along, that small anomaly – the 2-degree tilt of Deimos’ orbit with respect to Mars’ equator – held a clue to something very interesting about the red planet’s past … that Mars used to have rings!

Mars’ smallest moon, Deimos, as seen by the Mars Reconnaissance Orbiter spacecraft on February 21, 2009. The tilted orbit of the moon hints at ancient ring system around Mars. Image via NASA/ JPL-Caltech/ University of Arizona/ SETI Institute.

Lead author Matija Cuk at the SETI Institute explained in a statement:

The fact that Deimos’s orbit is not exactly in plane with Mars’s equator was considered unimportant, and nobody cared to try to explain it. But once we had a big new idea and we looked at it with new eyes, Deimos’s orbital tilt revealed its big secret.

Three years ago, scientists suggested that the larger of Mars’ two tiny moons – Phobos – might periodically create a ring system for Mars. In that scenario, Mars has had a series of rings, appearing in cycles over billions of years, and it will have rings again in the future. It happens because – for example, at present – Phobos is slowly orbiting closer and closer to Mars. Eventually, Mars’ gravity will rip Photos apart and the fabric of the moon’s body will form a ring. Later, the material in the ring will coalesce to form a moon again. The researchers think that this has happened many times over Mars’ history. The new paper on a Mars ring from the other moon, Deimos, speaks to this alternate theory:

Alternatively, Hesselbrock & Minton (2017) propose that Phobos is only the latest product of a repeating ring-satellite cycle at Mars, with each successive inner satellite being less massive than the preceding one. In the ring-satellite cycle model, satellites form from the outer edge of the ring, and then migrate outward through gravitational interaction with the ring. The ring loses mass to the planet at its inner edge, and once the ring is sufficiently depleted the satellite migrates inward due to tides.

How does this earlier idea relate to the new scenario involving Deimos?

According to the researchers, a newborn moon would move away from both the ring and Mars, heading in the opposite direction from Phobos, or any inwardly-migrating moon. An outwardly-migrating moon, just outside of the rings, could come to experience an orbital resonance – a situation where two orbiting bodies are exerting a regular, periodic gravitational influence on each other – so that the orbital period of Deimos comes to be precisely three times that of the other moon. The researchers’ statement explained:

These orbital resonances are picky but predictable … We can tell that only an outward-moving moon could have strongly affected Deimos, which means that Mars must have had a ring pushing the inner moon outward. Cuk and collaborators deduce that this moon may have been 20 times as massive as Phobos, and may have been its ‘grandparent’ existing just over 3 billion years ago … [that] was followed by two more ring-moon cycles, with the latest moon being Phobos.

Saturn, of course, has the most well-known rings in the solar system, as seen here by the Cassini spacecraft. Image via NASA/ JPL-Caltech.

The formation of Phobos probably happened about 3 1/2 billion years ago, Cuk told ScienceAlert:

Something like 3.5 billion years ago is our best bet. That agrees beautifully with Hesselbrock and Minton’s calculation on when Mars had an inner moon with 20 times the mass of Phobos. Once the ring was gone, the moon also started falling because of Martian tides (just like Phobos). Once it was too close to Mars, tidal forces would pull it apart into a new ring, and the cycle would repeat, probably twice, to get to Phobos that we see.

It’s known that Phobos is much younger than Deimos – perhaps as young as about 200 million years old in contrast to a few billion years old for Deimos – which would fit this scenario.

The findings are fascinating since they imply that Mars has had at least one prominent ring, and probably more, during its lifetime. This would mean that smaller rocky planets can also have rings, although none of those in our current solar system do.

On the other hand, scientists know that the ring process must be a common one in our solar system.

Artist’s concept of asteroid Chariklo, which, in 2014, was the first object in the solar system smaller than the gas or ice giant planets found to have rings. Image via ESO.

They know that because Jupiter, Saturn, Uranus and Neptune all are known to have rings. And, in 2014, astronomers discovered an asteroid – named Chariklo – with two dense and narrow rings. This was the first time that rings were found around any solar system object smaller than the gas or ice giant planets. Chariklo is a member of a group of asteroids called Centaurs that orbit between Jupiter and Neptune. Uffe Gråe Jørgensen at Niels Bohr Institute, University of Copenhagen in Denmark, said of Chariklo:

For me, it was quite amazing to realize that we were able not only to detect a ring system, but also pinpoint that it consists of two clearly distinct rings. I try to imagine how it would be to stand on the surface of this icy object – small enough that a fast sports car could reach escape velocity and drive off into space – and stare up at a 20-kilometer (12-mile) wide ring system 1,000 times closer than the moon.

In 2017, a ring was also discovered around the asteroid-like dwarf planet Haumea, which orbits beyond Neptune in the Kuiper Belt.

Matija Cuk at the SETI Institute, lead author of the new study. Image via SETI Institute.

The Japanese space agency JAXA is planning to send a new mission to Phobos in 2024, which will collect samples for return to Earth. This will hopefully provide more clues about Mars’ rings and the previous larger moon that Phobos came from. Cuk said:

I do theoretical calculations for a living, and they are good, but getting them tested against the real world now and then is even better.

It would be really cool if we could go back in time and see the rings of Mars as they once were. But, we can still learn about them by studying the clues left behind in the planet’s two remaining little moons, Deimos and Phobos.

Bottom line: A new research study of Mars’ smallest moon Deimos suggests that the planet used to have a ring or rings a few billion years ago.

Source: Evidence for a Past Martian Ring from the Orbital Inclination of Deimos

Via SETI Institute

from EarthSky https://ift.tt/30iqV0C

Artist’s concept of the red planet Mars with rings. Image via Kevin Gill on Flickr/ CC by 2.0.

Ring systems are common in our solar system. Jupiter, Saturn, Uranus and Neptune all have rings. None of the smaller rocky planets have them, but is it possible that some of them could have had rings in the past? On June 2, 2020, scientists from the SETI Institute and Purdue University announced evidence suggesting that Mars used to have its own rings a few billion years ago. The findings would help explain why Mars’ smallest moon, Deimos, has an unusually tilted orbit.

The researchers published the new peer-reviewed paper in Astrophysical Journal Letters on June 1, 2020. The research was also presented at the 236th Meeting of the American Astronomical Society (AAS 236), held virtually this week (June 1-3, 2020) due to COVID-19.

While the orbits of both small moons, Phobos and Deimos, lie almost in the same plane as Mars’ equator – suggesting they formed at the same time as Mars – Deimos’ orbit is tilted by about 2 degrees. This tilt was an unusual and unexplained finding. It was also considered to be not all that significant in terms of Mars science.

Now it seems that, all along, that small anomaly – the 2-degree tilt of Deimos’ orbit with respect to Mars’ equator – held a clue to something very interesting about the red planet’s past … that Mars used to have rings!

Mars’ smallest moon, Deimos, as seen by the Mars Reconnaissance Orbiter spacecraft on February 21, 2009. The tilted orbit of the moon hints at ancient ring system around Mars. Image via NASA/ JPL-Caltech/ University of Arizona/ SETI Institute.

Lead author Matija Cuk at the SETI Institute explained in a statement:

The fact that Deimos’s orbit is not exactly in plane with Mars’s equator was considered unimportant, and nobody cared to try to explain it. But once we had a big new idea and we looked at it with new eyes, Deimos’s orbital tilt revealed its big secret.

Three years ago, scientists suggested that the larger of Mars’ two tiny moons – Phobos – might periodically create a ring system for Mars. In that scenario, Mars has had a series of rings, appearing in cycles over billions of years, and it will have rings again in the future. It happens because – for example, at present – Phobos is slowly orbiting closer and closer to Mars. Eventually, Mars’ gravity will rip Photos apart and the fabric of the moon’s body will form a ring. Later, the material in the ring will coalesce to form a moon again. The researchers think that this has happened many times over Mars’ history. The new paper on a Mars ring from the other moon, Deimos, speaks to this alternate theory:

Alternatively, Hesselbrock & Minton (2017) propose that Phobos is only the latest product of a repeating ring-satellite cycle at Mars, with each successive inner satellite being less massive than the preceding one. In the ring-satellite cycle model, satellites form from the outer edge of the ring, and then migrate outward through gravitational interaction with the ring. The ring loses mass to the planet at its inner edge, and once the ring is sufficiently depleted the satellite migrates inward due to tides.

How does this earlier idea relate to the new scenario involving Deimos?

According to the researchers, a newborn moon would move away from both the ring and Mars, heading in the opposite direction from Phobos, or any inwardly-migrating moon. An outwardly-migrating moon, just outside of the rings, could come to experience an orbital resonance – a situation where two orbiting bodies are exerting a regular, periodic gravitational influence on each other – so that the orbital period of Deimos comes to be precisely three times that of the other moon. The researchers’ statement explained:

These orbital resonances are picky but predictable … We can tell that only an outward-moving moon could have strongly affected Deimos, which means that Mars must have had a ring pushing the inner moon outward. Cuk and collaborators deduce that this moon may have been 20 times as massive as Phobos, and may have been its ‘grandparent’ existing just over 3 billion years ago … [that] was followed by two more ring-moon cycles, with the latest moon being Phobos.

Saturn, of course, has the most well-known rings in the solar system, as seen here by the Cassini spacecraft. Image via NASA/ JPL-Caltech.

The formation of Phobos probably happened about 3 1/2 billion years ago, Cuk told ScienceAlert:

Something like 3.5 billion years ago is our best bet. That agrees beautifully with Hesselbrock and Minton’s calculation on when Mars had an inner moon with 20 times the mass of Phobos. Once the ring was gone, the moon also started falling because of Martian tides (just like Phobos). Once it was too close to Mars, tidal forces would pull it apart into a new ring, and the cycle would repeat, probably twice, to get to Phobos that we see.

It’s known that Phobos is much younger than Deimos – perhaps as young as about 200 million years old in contrast to a few billion years old for Deimos – which would fit this scenario.

The findings are fascinating since they imply that Mars has had at least one prominent ring, and probably more, during its lifetime. This would mean that smaller rocky planets can also have rings, although none of those in our current solar system do.

On the other hand, scientists know that the ring process must be a common one in our solar system.

Artist’s concept of asteroid Chariklo, which, in 2014, was the first object in the solar system smaller than the gas or ice giant planets found to have rings. Image via ESO.

They know that because Jupiter, Saturn, Uranus and Neptune all are known to have rings. And, in 2014, astronomers discovered an asteroid – named Chariklo – with two dense and narrow rings. This was the first time that rings were found around any solar system object smaller than the gas or ice giant planets. Chariklo is a member of a group of asteroids called Centaurs that orbit between Jupiter and Neptune. Uffe Gråe Jørgensen at Niels Bohr Institute, University of Copenhagen in Denmark, said of Chariklo:

For me, it was quite amazing to realize that we were able not only to detect a ring system, but also pinpoint that it consists of two clearly distinct rings. I try to imagine how it would be to stand on the surface of this icy object – small enough that a fast sports car could reach escape velocity and drive off into space – and stare up at a 20-kilometer (12-mile) wide ring system 1,000 times closer than the moon.

In 2017, a ring was also discovered around the asteroid-like dwarf planet Haumea, which orbits beyond Neptune in the Kuiper Belt.

Matija Cuk at the SETI Institute, lead author of the new study. Image via SETI Institute.

The Japanese space agency JAXA is planning to send a new mission to Phobos in 2024, which will collect samples for return to Earth. This will hopefully provide more clues about Mars’ rings and the previous larger moon that Phobos came from. Cuk said:

I do theoretical calculations for a living, and they are good, but getting them tested against the real world now and then is even better.

It would be really cool if we could go back in time and see the rings of Mars as they once were. But, we can still learn about them by studying the clues left behind in the planet’s two remaining little moons, Deimos and Phobos.

Bottom line: A new research study of Mars’ smallest moon Deimos suggests that the planet used to have a ring or rings a few billion years ago.

Source: Evidence for a Past Martian Ring from the Orbital Inclination of Deimos

Via SETI Institute

from EarthSky https://ift.tt/30iqV0C

Black holes are like a hologram

Who could forget this image? It’s the first direct image of a black hole, in the galaxy M87, released in April 2019. This long-sought image provided the strongest evidence to date for the existence of supermassive black holes and opened a new window onto the study of black holes, their event horizons, and gravity. Image via the Event Horizon Telescope Collaboration.

Reprinted from the International School of Advanced Studies (SISSA) in Trieste, Italy.

We all remember that incredible image of a black hole that traveled around the world about a year ago. Yet, according to new research by scientists in Italy, black holes could be like a hologram, where all the information is amassed in a two-dimensional surface able to reproduce a three-dimensional image. In this way, these cosmic bodies, as affirmed by quantum theories, could be incredibly complex and concentrate an enormous amount of information inside themselves, as the largest hard disk that exists in nature, in two dimensions. This idea aligns with Einstein’s theory of relativity, which describes black holes as three dimensional, simple, spherical, and smooth, as they appear in that famous image. In short, black holes “appear” as three dimensional, just like holograms. The study which demonstrates it, and which unites two discordant theories, has recently been published in Physical Review X.

The study comes from the SISSA, and from the International Centre for Theoretical Physics (ICTP) and the National Institute for Nuclear Physics (INFN), all based in Italy.

The mystery of black holes

For scientists, black holes are a big question mark for many reasons. They are, for example, excellent representatives of the great difficulties of theoretical physics in putting together the principles of Einstein’s general theory of relativity with those of quantum physics when it comes to gravity. According to the first theory, they would be simple bodies without information. According to the other, as claimed by Jacob Bekenstein and Stephen Hawking, they would be “the most complex existing systems” because they would be characterized by an enormous “entropy,” which measures the complexity of a system, and consequently would have a lot of information inside them.

The holographic principle applied to black holes

To study black holes, the two authors of the research, Francesco Benini (SISSA Professor, ICTP scientific consultant and INFN researcher) and Paolo Milan (SISSA and INFN researcher), used an idea almost 30 years old, but still surprising, called the holographic principle.

The researchers said:

This revolutionary and somewhat counterintuitive principle proposes that the behavior of gravity in a given region of space can alternatively be described in terms of a different system, which lives only along the edge of that region and therefore in a one less dimension.

And, more importantly, in this alternative description (called holographic) gravity does not appear explicitly. In other words, the holographic principle allows us to describe gravity using a language that does not contain gravity, thus avoiding friction with quantum mechanics.

What Benini and Milan have done is:

… apply the theory of the holographic principle to black holes. In this way, their mysterious thermodynamic properties have become more understandable: focusing on predicting that these bodies have a great entropy and observing them in terms of quantum mechanics, you can describe them just like a hologram: they have two dimensions, in which gravity disappears, but they reproduce an object in three dimensions.

From theory to observation

The two scientists explained:

This study is only the first step towards a deeper understanding of these cosmic bodies and of the properties that characterize them when quantum mechanics crosses with general relativity.

Everything is more important now at a time when observations in astrophysics are experiencing an incredible development. Just think of the observation of gravitational waves from the fusion of black holes result of the collaboration between LIGO and Virgo or, indeed, that of the black hole made by the Event Horizon Telescope that produced this extraordinary image.

In the near future, we may be able to test our theoretical predictions regarding quantum gravity, such as those made in this study, by observation. And this, from a scientific point of view, would be something absolutely exceptional.

Artist’s concept of a black hole via SISSA.

Bottom line: The theory of relativity describes black holes as being spherical, smooth and simple. Quantum theory describes them as being extremely complex and full of information. Two scientists in Italy have applied the theory of the holographic principle to black holes in a way that appears to resolve this duality.

Source: Black Holes in 4D N = 4 Super-Yang-Mills Field Theory

Via SISSA

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

Who could forget this image? It’s the first direct image of a black hole, in the galaxy M87, released in April 2019. This long-sought image provided the strongest evidence to date for the existence of supermassive black holes and opened a new window onto the study of black holes, their event horizons, and gravity. Image via the Event Horizon Telescope Collaboration.

Reprinted from the International School of Advanced Studies (SISSA) in Trieste, Italy.

We all remember that incredible image of a black hole that traveled around the world about a year ago. Yet, according to new research by scientists in Italy, black holes could be like a hologram, where all the information is amassed in a two-dimensional surface able to reproduce a three-dimensional image. In this way, these cosmic bodies, as affirmed by quantum theories, could be incredibly complex and concentrate an enormous amount of information inside themselves, as the largest hard disk that exists in nature, in two dimensions. This idea aligns with Einstein’s theory of relativity, which describes black holes as three dimensional, simple, spherical, and smooth, as they appear in that famous image. In short, black holes “appear” as three dimensional, just like holograms. The study which demonstrates it, and which unites two discordant theories, has recently been published in Physical Review X.

The study comes from the SISSA, and from the International Centre for Theoretical Physics (ICTP) and the National Institute for Nuclear Physics (INFN), all based in Italy.

The mystery of black holes

For scientists, black holes are a big question mark for many reasons. They are, for example, excellent representatives of the great difficulties of theoretical physics in putting together the principles of Einstein’s general theory of relativity with those of quantum physics when it comes to gravity. According to the first theory, they would be simple bodies without information. According to the other, as claimed by Jacob Bekenstein and Stephen Hawking, they would be “the most complex existing systems” because they would be characterized by an enormous “entropy,” which measures the complexity of a system, and consequently would have a lot of information inside them.

The holographic principle applied to black holes

To study black holes, the two authors of the research, Francesco Benini (SISSA Professor, ICTP scientific consultant and INFN researcher) and Paolo Milan (SISSA and INFN researcher), used an idea almost 30 years old, but still surprising, called the holographic principle.

The researchers said:

This revolutionary and somewhat counterintuitive principle proposes that the behavior of gravity in a given region of space can alternatively be described in terms of a different system, which lives only along the edge of that region and therefore in a one less dimension.

And, more importantly, in this alternative description (called holographic) gravity does not appear explicitly. In other words, the holographic principle allows us to describe gravity using a language that does not contain gravity, thus avoiding friction with quantum mechanics.

What Benini and Milan have done is:

… apply the theory of the holographic principle to black holes. In this way, their mysterious thermodynamic properties have become more understandable: focusing on predicting that these bodies have a great entropy and observing them in terms of quantum mechanics, you can describe them just like a hologram: they have two dimensions, in which gravity disappears, but they reproduce an object in three dimensions.

From theory to observation

The two scientists explained:

This study is only the first step towards a deeper understanding of these cosmic bodies and of the properties that characterize them when quantum mechanics crosses with general relativity.

Everything is more important now at a time when observations in astrophysics are experiencing an incredible development. Just think of the observation of gravitational waves from the fusion of black holes result of the collaboration between LIGO and Virgo or, indeed, that of the black hole made by the Event Horizon Telescope that produced this extraordinary image.

In the near future, we may be able to test our theoretical predictions regarding quantum gravity, such as those made in this study, by observation. And this, from a scientific point of view, would be something absolutely exceptional.

Artist’s concept of a black hole via SISSA.

Bottom line: The theory of relativity describes black holes as being spherical, smooth and simple. Quantum theory describes them as being extremely complex and full of information. Two scientists in Italy have applied the theory of the holographic principle to black holes in a way that appears to resolve this duality.

Source: Black Holes in 4D N = 4 Super-Yang-Mills Field Theory

Via SISSA

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

Scientist identify cleanest air on Earth

The Southern Ocean. Image via Spartan & the green egg

Researchers have identified Earth’s cleanest air – free of particles caused by our human activity – in a region in the Southern Ocean off the coast of Antartica.

Weather and climate are complex processes that connect each part of the world to every other region. A team of climate scientists from Colorado State University were curious to see just how far particles produced by human industry and activity reach. To find out, they sailed from Tasmania into the Southern Ocean – which encircles Antartica below 40 degrees south latitude – and measured the bioaerosol composition – the particles in the atmosphere – at several points.

Location of the Southern Ocean. Image via Brittanica.

They took measurements from the boundary layer, a part of the lower atmosphere that comes in direct contact with the ocean’s surface and reaches as high as 1.2 miles (1.9 km) into the atmosphere.

The study, published June 1, 2020, in Proceedings of the National Academy of Sciences, found the boundary layer air that feeds the lower clouds over the Southern Ocean to be pristine, free from particles, called aerosols, connected to human pollution or other activity or transported from distant lands.

Aerosol filter samplers probe the air over the Southern Ocean on the Australian Marine National Facility’s R/V Investigator. Image via Kathryn Moore/ Colorado State University.

The researchers said that it’s difficult to find any area or process on Earth untouched by people. The scientists suspected the air directly over the remote Southern Ocean that encircles Antarctica would be least affected by humans and dust from continents. They set out to discover what was in the air and where it came from. Colorado State University research scientist Thomas Hill is a study coauthor. Hill said in a statement:

We were able to use the bacteria in the air over the Southern Ocean as a diagnostic tool to infer key properties of the lower atmosphere. For example, that the aerosols controlling the properties of Southern Ocean clouds are strongly linked to ocean biological processes, and that Antarctica appears to be isolated from southward dispersal of microorganisms and nutrient deposition from southern continents. Overall, it suggests that the Southern Ocean is one of very few places on Earth that has been minimally affected by anthropogenic activities.

These results counter other studies from oceans in the subtropics and northern hemisphere, which found that most microbes came from upwind continents.

Bottom line: A new study suggests the cleanest air on Earth – free from pollution from human activities – is in a region of the Southern Ocean which surrounds Antarctica.

Source: Airborne bacteria confirm the pristine nature of the Southern Ocean boundary layer

Via Colorado State University

from EarthSky https://ift.tt/3eU90Sg

The Southern Ocean. Image via Spartan & the green egg

Researchers have identified Earth’s cleanest air – free of particles caused by our human activity – in a region in the Southern Ocean off the coast of Antartica.

Weather and climate are complex processes that connect each part of the world to every other region. A team of climate scientists from Colorado State University were curious to see just how far particles produced by human industry and activity reach. To find out, they sailed from Tasmania into the Southern Ocean – which encircles Antartica below 40 degrees south latitude – and measured the bioaerosol composition – the particles in the atmosphere – at several points.

Location of the Southern Ocean. Image via Brittanica.

They took measurements from the boundary layer, a part of the lower atmosphere that comes in direct contact with the ocean’s surface and reaches as high as 1.2 miles (1.9 km) into the atmosphere.

The study, published June 1, 2020, in Proceedings of the National Academy of Sciences, found the boundary layer air that feeds the lower clouds over the Southern Ocean to be pristine, free from particles, called aerosols, connected to human pollution or other activity or transported from distant lands.

Aerosol filter samplers probe the air over the Southern Ocean on the Australian Marine National Facility’s R/V Investigator. Image via Kathryn Moore/ Colorado State University.

The researchers said that it’s difficult to find any area or process on Earth untouched by people. The scientists suspected the air directly over the remote Southern Ocean that encircles Antarctica would be least affected by humans and dust from continents. They set out to discover what was in the air and where it came from. Colorado State University research scientist Thomas Hill is a study coauthor. Hill said in a statement:

We were able to use the bacteria in the air over the Southern Ocean as a diagnostic tool to infer key properties of the lower atmosphere. For example, that the aerosols controlling the properties of Southern Ocean clouds are strongly linked to ocean biological processes, and that Antarctica appears to be isolated from southward dispersal of microorganisms and nutrient deposition from southern continents. Overall, it suggests that the Southern Ocean is one of very few places on Earth that has been minimally affected by anthropogenic activities.

These results counter other studies from oceans in the subtropics and northern hemisphere, which found that most microbes came from upwind continents.

Bottom line: A new study suggests the cleanest air on Earth – free from pollution from human activities – is in a region of the Southern Ocean which surrounds Antarctica.

Source: Airborne bacteria confirm the pristine nature of the Southern Ocean boundary layer

Via Colorado State University

from EarthSky https://ift.tt/3eU90Sg

Despite the full moon, comet Lemmon!

June 4, 2020, capture of comet C/2019 U6 (Lemmon) via Terry Lovejoy of Australia.

As always, there are multiple comets in the sky now, but one to watch is comet C/2019 U6 (Lemmon), which will make its closest approach to the sun on June 18, 2020, and which is currently visible in binoculars from Southern Hemisphere locations at an apparent magnitude of about 7. The comet is moving northward and will enter northern skies soon. By some reports, this comet might become nearly visible to the unaided eye this month. Seeing it will require finder charts and a very dark sky. Still, we’re hearing good reports about this comet. Veteran comet hunter Terry Lovejoy wrote on Twitter on June 4:

Even with a full moon, Comet Lemmon looking good. 10x20sec with C14 Hyperstar + QHY183c.

Terry is an experienced observer and astrophotographer, with comets bearing his name, and he captured this image with a 14-inch telescope and CCD imaging. The comet is not visible to the eye. Still, it’s a nice comet, isn’t it? Check out that tail!

Comet C/2019 U6 (Lemmon) is currently in the constellation Canis Major the Greater Dog, which means it’s currently a Southern Hemisphere object, but it’ll move into northern skies later this month (see finder charts). Here’s some information about comet Lemmon from TheSkyLive.com:

The current Right Ascension of Comet C/2019 U6 (Lemmon) is 07h 28m 47s and the Declination is -18° 11’ 15” … The current estimated magnitude of Comet C/2019 U6 (Lemmon) is 11.46 (JPL) while the latest observed magnitude is 7.0 (COBS).

Bright comets are the ones that get all the attention. And yet, although most of us aren’t aware of it, there are multiple faint comets visible via the telescopes of astronomers at any given time. You’ll find a list of comets in the sky now via In-The-Sky.org.

Follow Terry Lovejoy on Twitter.

Or read about him on Wikipedia.

Bottom line: A beautiful CCD image of comet C/2019 U6 (Lemmon), taken June 4, 2020, by Terry Lovejoy.

from EarthSky https://ift.tt/3cCBcHy

June 4, 2020, capture of comet C/2019 U6 (Lemmon) via Terry Lovejoy of Australia.

As always, there are multiple comets in the sky now, but one to watch is comet C/2019 U6 (Lemmon), which will make its closest approach to the sun on June 18, 2020, and which is currently visible in binoculars from Southern Hemisphere locations at an apparent magnitude of about 7. The comet is moving northward and will enter northern skies soon. By some reports, this comet might become nearly visible to the unaided eye this month. Seeing it will require finder charts and a very dark sky. Still, we’re hearing good reports about this comet. Veteran comet hunter Terry Lovejoy wrote on Twitter on June 4:

Even with a full moon, Comet Lemmon looking good. 10x20sec with C14 Hyperstar + QHY183c.

Terry is an experienced observer and astrophotographer, with comets bearing his name, and he captured this image with a 14-inch telescope and CCD imaging. The comet is not visible to the eye. Still, it’s a nice comet, isn’t it? Check out that tail!

Comet C/2019 U6 (Lemmon) is currently in the constellation Canis Major the Greater Dog, which means it’s currently a Southern Hemisphere object, but it’ll move into northern skies later this month (see finder charts). Here’s some information about comet Lemmon from TheSkyLive.com:

The current Right Ascension of Comet C/2019 U6 (Lemmon) is 07h 28m 47s and the Declination is -18° 11’ 15” … The current estimated magnitude of Comet C/2019 U6 (Lemmon) is 11.46 (JPL) while the latest observed magnitude is 7.0 (COBS).

Bright comets are the ones that get all the attention. And yet, although most of us aren’t aware of it, there are multiple faint comets visible via the telescopes of astronomers at any given time. You’ll find a list of comets in the sky now via In-The-Sky.org.

Follow Terry Lovejoy on Twitter.

Or read about him on Wikipedia.

Bottom line: A beautiful CCD image of comet C/2019 U6 (Lemmon), taken June 4, 2020, by Terry Lovejoy.

from EarthSky https://ift.tt/3cCBcHy