Epic cosmic explosion detected via faster-than-light particles

Specialized telescopes – like H.E.S.S. in Namibia and MAGIC in the Canary Islands – detect the bluish Cherenkov light in Earth’s atmosphere, generated by faster-than-light particles, caused by cosmic gamma rays. Image via DESY Science Communication Lab.

On January 14, 2019, two NASA space observatories – Swift and Fermi – detected a burst of gamma rays from a source billions of light-years away. That’s not unusual in and of itself; these space telescopes detect gamma ray bursts about once daily, routinely sending automatic alerts to other gamma-ray observatories around the world. But this burst – labeled GRB 190114C – was different. It became the most powerful yet detected by a specialized telescope on Earth’s surface, where scientists registered the highest energy gamma rays ever measured from a gamma ray burst, reaching about 100 billion times as much energy as visible light. The MAGIC telescope in the Canary Islands was able to point to the region of origin so quickly that it began observing the event within only 57 seconds of the space-based observations. Its scientists presented their observations last week (November 20, 2019) in two independent studies in the peer-reviewed journal Nature.

In the same issue of Nature, scientists presented a study of an earlier gamma ray burst – labeled GRB 180720B – not as strong but also detected on the ground via the H.E.S.S. telescope in Namibia on July 20, 2018. Read an overview of the three Nature studies here.

These two ground-based detections – from January 2019 and July 2018 – are the first detections of gamma-ray bursts with ground-based gamma-ray telescopes. They come after many years of trying to catch such events.

The power of these cosmic explosions is mind-boggling. But their detection is fascinating as well. The ground-based H.E.S.S. and MAGIC telescopes didn’t detect the gamma rays directly. They detected their effect on Earth’s atmosphere, via faster-than-light particles known as Cherenkov radiation. The Deutsches Elektronen-Synchrotron (DESY) – a national research center in Germany that operates particle accelerators and that also plays a role in operating both H.E.S.S. and MAGIC – explained in a statement:

When an energetic cosmic gamma ray hits Earth’s atmosphere, it shatters molecules and atoms. This process creates an avalanche of particles called an air shower. The shower particles are so energetic that they move faster through the air than light – although not faster than light in a vacuum, which according to Albert Einstein’s theory of relativity is the absolute upper speed limit. The result is a bluish glow, a kind of optical counterpart to the supersonic bang. This Cherenkov light, named after its discoverer, can be observed by Cherenkov telescopes such as those of the H.E.S.S. and MAGIC observatories …

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The Hubble Space Telescope caught the fading afterglow of GRB 190114C and its home galaxy on February 11 and March 12, 2019. The difference between these images reveals a faint, short-lived glow (center of the green circle) located about 800 light-years from the galaxy’s core. Blue colors beyond the core signal the presence of hot, young stars, indicating that this is a spiral galaxy somewhat similar to our own. The source of the burst is located about 4.5 billion light-years away in the direction of the constellation Fornax. Image via NASA/ESA/V. Acciari et al./ICRAR.

Gamma-ray bursts – called GRBs by scientists – are sudden, short bursts of gamma radiation from the cosmos. They were discovered by chance at the end of the 1960s by satellites used to monitor compliance with the nuclear test ban on Earth. These bursts are thought to originate from colliding neutron stars or supernova explosions. David Berge, head of gamma-ray astronomy at DESY, said:

Gamma-ray bursts are the most powerful explosions known in the universe and typically release more energy in just a few seconds than our sun during its entire lifetime – they can shine through almost the entire visible universe.

Since the 1960s, astronomers have been studying gamma-ray bursts with satellites. Earth’s atmosphere absorbs gamma rays; Earth-based telescopes can’t detect cosmic gamma rays directly. Telescopes like H.E.S.S. and MAGIC are designed to detect a faint blue glow in the atmosphere – Cherenkov light – induced by cosmic gamma rays.

The detection of these two recent gamma ray bursts by these ground-based observatories was a culmination of years of effort by astronomers.

View larger. | What are gamma ray bursts? They are cosmic explosions, with radiation up to a trillion times the energy of visible light. This illustration shows the set-up for the most common type of gamma ray burst. The core of a massive star (left) has collapsed and formed a black hole. This “engine” drives a jet of particles that moves through the collapsing star and out into space at nearly the speed of light. The prompt emission, which typically lasts a minute or less, may arise from the jet’s interaction with gas near the newborn black hole and from collisions between shells of fast-moving gas within the jet (internal shock waves). The afterglow emission occurs as the leading edge of the jet sweeps up its surroundings (creating an external shock wave) and emits radiation across the spectrum for some time — months to years, in the case of radio and visible light, and many hours at the highest gamma-ray energies yet observed. These far exceed 100 billion electron volts (GeV) for two recent GRBs. Image via NASA’s Goddard Space Flight Center/ICRAR.

One reason the result could be achieved was that – when space-based observatories detect a gamma ray burst – they quickly alert the entire observational community. In the case of the January 2019 gamma ray bust, more than 20 different telescopes were able to obtain a deeper look at the burst’s source. DESY said:

This allowed [them] to pinpoint the details of the physical mechanism responsible for the highest-energy emission, as described in the second paper led by the MAGIC collaboration. Follow-up observations placed GRB 190114C at a distance of more than four billion light-years. This means, its light travelled more than four billion years to us, or about a third of the current age of the universe.

GRB 180720B, at a distance of six billion light years even further away, could still be detected in gamma rays at energies between 100 and 440 billion electron volts long after the initial blast.

DESY theorist Andrew Taylor, who contributed to the H.E.S.S. analysis, commented:

The detection came quite unexpected, as gamma-ray bursts are fading fast, leaving behind an afterglow which can be seen for hours to days across many wavelengths from radio to X-rays, but had never been detected in very-high-energy gamma rays before.

This success is also due to an improved follow-up strategy in which we also concentrate on observations at later times after the actual star collapse.

Read more about these recent gamma ray bursts via DESY

Read more about these recent gamma ray bursts via ICRAR

Artist’s concept of the January 14, 2019, gamma ray burst, caught by the MAGIC observatory in the Canary Islands. Image via Superbossa.com/C. Righi/ICRAR.

Bottom line: On January 14, 2019, space-based observatories detected a violent explosion in a galaxy billions of light-years away. GRB 190114C became the brightest source of high-energy cosmic gamma rays seen so far. The MAGIC telescope in the Canary Islands was able to detect it via faster-than-light Cherenkov radiation cascading through Earth’s atmosphere. This observation – combined with a similar observation of another gamma ray burst, GRB 180720B, from July 2018 – were the successful culmination of years of effort by astronomers.

Source: Extreme emission seen from gamma-ray bursts

Via DESY

Via ICRAR

from EarthSky https://ift.tt/2KQfMM5

Specialized telescopes – like H.E.S.S. in Namibia and MAGIC in the Canary Islands – detect the bluish Cherenkov light in Earth’s atmosphere, generated by faster-than-light particles, caused by cosmic gamma rays. Image via DESY Science Communication Lab.

On January 14, 2019, two NASA space observatories – Swift and Fermi – detected a burst of gamma rays from a source billions of light-years away. That’s not unusual in and of itself; these space telescopes detect gamma ray bursts about once daily, routinely sending automatic alerts to other gamma-ray observatories around the world. But this burst – labeled GRB 190114C – was different. It became the most powerful yet detected by a specialized telescope on Earth’s surface, where scientists registered the highest energy gamma rays ever measured from a gamma ray burst, reaching about 100 billion times as much energy as visible light. The MAGIC telescope in the Canary Islands was able to point to the region of origin so quickly that it began observing the event within only 57 seconds of the space-based observations. Its scientists presented their observations last week (November 20, 2019) in two independent studies in the peer-reviewed journal Nature.

In the same issue of Nature, scientists presented a study of an earlier gamma ray burst – labeled GRB 180720B – not as strong but also detected on the ground via the H.E.S.S. telescope in Namibia on July 20, 2018. Read an overview of the three Nature studies here.

These two ground-based detections – from January 2019 and July 2018 – are the first detections of gamma-ray bursts with ground-based gamma-ray telescopes. They come after many years of trying to catch such events.

The power of these cosmic explosions is mind-boggling. But their detection is fascinating as well. The ground-based H.E.S.S. and MAGIC telescopes didn’t detect the gamma rays directly. They detected their effect on Earth’s atmosphere, via faster-than-light particles known as Cherenkov radiation. The Deutsches Elektronen-Synchrotron (DESY) – a national research center in Germany that operates particle accelerators and that also plays a role in operating both H.E.S.S. and MAGIC – explained in a statement:

When an energetic cosmic gamma ray hits Earth’s atmosphere, it shatters molecules and atoms. This process creates an avalanche of particles called an air shower. The shower particles are so energetic that they move faster through the air than light – although not faster than light in a vacuum, which according to Albert Einstein’s theory of relativity is the absolute upper speed limit. The result is a bluish glow, a kind of optical counterpart to the supersonic bang. This Cherenkov light, named after its discoverer, can be observed by Cherenkov telescopes such as those of the H.E.S.S. and MAGIC observatories …

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

The Hubble Space Telescope caught the fading afterglow of GRB 190114C and its home galaxy on February 11 and March 12, 2019. The difference between these images reveals a faint, short-lived glow (center of the green circle) located about 800 light-years from the galaxy’s core. Blue colors beyond the core signal the presence of hot, young stars, indicating that this is a spiral galaxy somewhat similar to our own. The source of the burst is located about 4.5 billion light-years away in the direction of the constellation Fornax. Image via NASA/ESA/V. Acciari et al./ICRAR.

Gamma-ray bursts – called GRBs by scientists – are sudden, short bursts of gamma radiation from the cosmos. They were discovered by chance at the end of the 1960s by satellites used to monitor compliance with the nuclear test ban on Earth. These bursts are thought to originate from colliding neutron stars or supernova explosions. David Berge, head of gamma-ray astronomy at DESY, said:

Gamma-ray bursts are the most powerful explosions known in the universe and typically release more energy in just a few seconds than our sun during its entire lifetime – they can shine through almost the entire visible universe.

Since the 1960s, astronomers have been studying gamma-ray bursts with satellites. Earth’s atmosphere absorbs gamma rays; Earth-based telescopes can’t detect cosmic gamma rays directly. Telescopes like H.E.S.S. and MAGIC are designed to detect a faint blue glow in the atmosphere – Cherenkov light – induced by cosmic gamma rays.

The detection of these two recent gamma ray bursts by these ground-based observatories was a culmination of years of effort by astronomers.

View larger. | What are gamma ray bursts? They are cosmic explosions, with radiation up to a trillion times the energy of visible light. This illustration shows the set-up for the most common type of gamma ray burst. The core of a massive star (left) has collapsed and formed a black hole. This “engine” drives a jet of particles that moves through the collapsing star and out into space at nearly the speed of light. The prompt emission, which typically lasts a minute or less, may arise from the jet’s interaction with gas near the newborn black hole and from collisions between shells of fast-moving gas within the jet (internal shock waves). The afterglow emission occurs as the leading edge of the jet sweeps up its surroundings (creating an external shock wave) and emits radiation across the spectrum for some time — months to years, in the case of radio and visible light, and many hours at the highest gamma-ray energies yet observed. These far exceed 100 billion electron volts (GeV) for two recent GRBs. Image via NASA’s Goddard Space Flight Center/ICRAR.

One reason the result could be achieved was that – when space-based observatories detect a gamma ray burst – they quickly alert the entire observational community. In the case of the January 2019 gamma ray bust, more than 20 different telescopes were able to obtain a deeper look at the burst’s source. DESY said:

This allowed [them] to pinpoint the details of the physical mechanism responsible for the highest-energy emission, as described in the second paper led by the MAGIC collaboration. Follow-up observations placed GRB 190114C at a distance of more than four billion light-years. This means, its light travelled more than four billion years to us, or about a third of the current age of the universe.

GRB 180720B, at a distance of six billion light years even further away, could still be detected in gamma rays at energies between 100 and 440 billion electron volts long after the initial blast.

DESY theorist Andrew Taylor, who contributed to the H.E.S.S. analysis, commented:

The detection came quite unexpected, as gamma-ray bursts are fading fast, leaving behind an afterglow which can be seen for hours to days across many wavelengths from radio to X-rays, but had never been detected in very-high-energy gamma rays before.

This success is also due to an improved follow-up strategy in which we also concentrate on observations at later times after the actual star collapse.

Read more about these recent gamma ray bursts via DESY

Read more about these recent gamma ray bursts via ICRAR

Artist’s concept of the January 14, 2019, gamma ray burst, caught by the MAGIC observatory in the Canary Islands. Image via Superbossa.com/C. Righi/ICRAR.

Bottom line: On January 14, 2019, space-based observatories detected a violent explosion in a galaxy billions of light-years away. GRB 190114C became the brightest source of high-energy cosmic gamma rays seen so far. The MAGIC telescope in the Canary Islands was able to detect it via faster-than-light Cherenkov radiation cascading through Earth’s atmosphere. This observation – combined with a similar observation of another gamma ray burst, GRB 180720B, from July 2018 – were the successful culmination of years of effort by astronomers.

Source: Extreme emission seen from gamma-ray bursts

Via DESY

Via ICRAR

from EarthSky https://ift.tt/2KQfMM5

News digest – A&E diagnoses, teen inactivity, NHS staff shortages and arthritis drugs

NHS staff shortages in Scotland limiting progress

Lives are being put at risk in Scotland because of NHS staff shortages, says BBC News. A new report looking at cancer care found that more than 18 in 100 people diagnosed with cancer had to wait longer than 62 days for their diagnosis. Our CEO called for NHS Scotland to publish their long-term cancer workforce plan, which will help the NHS prepare for rising demands on the health service in the future.

One in 5 diagnosed with cancer in A&E in Northern Ireland

In Northern Ireland, 1 in 5 patients are being diagnosed with cancer in A&E. According to BBC News, the problem, which is more likely to affect older patients, could result from people waiting too long to see a specialist.

Health warnings on e-cigs may stop people switching from smoking

Vaping has had mixed coverage recently. Our study looking at the impact of different types of warning labels on e-cigarettes has found that language matters. Researchers found the current messages on e-cigarettes, which focuses on the addictive nature of nicotine, put some smokers off using them to quit. Whereas a warning label stating that the product is less harmful than smoking made smokers more likely to consider using the products, without encouraging non-smokers to start. Read the Independent for the details.

Global inactivity among teens

Youngsters around the world are not doing enough exercise, according to new figures from the World Health Organisation (WHO) reported by the Guardian. The survey of schools from 146 countries found that around 4 in 5 teens from 11 to 17 years old are not meeting the recommended daily hour of physical activity. And UK figures from 2016 showed that more than 85 in 100 girls and almost 75 in 100 boys were not active enough. The researchers suggested that measures to make sure sport and leisure facilities are safe, accessible and affordable could help young people be more active.

Drug combo shrinks pancreatic cancer in mice

New research in the US has shown that a drug combination using two existing cancer drugs can shrink pancreatic cancer tumours in mice, reports the Mail Online. The scientists say this combo may be effective because it attacks the cancer with a double hit, as one drugs starves cancer cells of nutrients while the second stops the disease entering survival mode when its fuel supply is cut. It’s a promising step, but the drugs now need to be tested in people to see if the combination could have the same effect.

Delays to cervical screening results

Pulse reports new data released from Public Health England (PHE) showing that over half of cervical cancer screening letters were delayed last year. Only around 48 in 100 letters were received within the expected 2-week time frame, with over a third of people waiting more than 3 weeks for their results.

And finally…

A drug used to treat arthritis can stop breast cancer spreading and settling in the bones of mice. It’s thought the effect could be because the drugs block a molecule made by the bone that encourages breast cancer cells to grow into tumours in the bone. But before this existing drug can be repurposed, trials need to be carried out to see if the drug have the same effect in people. Read the Telegraph for more on these interesting findings.

Gabi

from Cancer Research UK – Science blog https://ift.tt/2rfaR0v

NHS staff shortages in Scotland limiting progress

Lives are being put at risk in Scotland because of NHS staff shortages, says BBC News. A new report looking at cancer care found that more than 18 in 100 people diagnosed with cancer had to wait longer than 62 days for their diagnosis. Our CEO called for NHS Scotland to publish their long-term cancer workforce plan, which will help the NHS prepare for rising demands on the health service in the future.

One in 5 diagnosed with cancer in A&E in Northern Ireland

In Northern Ireland, 1 in 5 patients are being diagnosed with cancer in A&E. According to BBC News, the problem, which is more likely to affect older patients, could result from people waiting too long to see a specialist.

Health warnings on e-cigs may stop people switching from smoking

Vaping has had mixed coverage recently. Our study looking at the impact of different types of warning labels on e-cigarettes has found that language matters. Researchers found the current messages on e-cigarettes, which focuses on the addictive nature of nicotine, put some smokers off using them to quit. Whereas a warning label stating that the product is less harmful than smoking made smokers more likely to consider using the products, without encouraging non-smokers to start. Read the Independent for the details.

Global inactivity among teens

Youngsters around the world are not doing enough exercise, according to new figures from the World Health Organisation (WHO) reported by the Guardian. The survey of schools from 146 countries found that around 4 in 5 teens from 11 to 17 years old are not meeting the recommended daily hour of physical activity. And UK figures from 2016 showed that more than 85 in 100 girls and almost 75 in 100 boys were not active enough. The researchers suggested that measures to make sure sport and leisure facilities are safe, accessible and affordable could help young people be more active.

Drug combo shrinks pancreatic cancer in mice

New research in the US has shown that a drug combination using two existing cancer drugs can shrink pancreatic cancer tumours in mice, reports the Mail Online. The scientists say this combo may be effective because it attacks the cancer with a double hit, as one drugs starves cancer cells of nutrients while the second stops the disease entering survival mode when its fuel supply is cut. It’s a promising step, but the drugs now need to be tested in people to see if the combination could have the same effect.

Delays to cervical screening results

Pulse reports new data released from Public Health England (PHE) showing that over half of cervical cancer screening letters were delayed last year. Only around 48 in 100 letters were received within the expected 2-week time frame, with over a third of people waiting more than 3 weeks for their results.

And finally…

A drug used to treat arthritis can stop breast cancer spreading and settling in the bones of mice. It’s thought the effect could be because the drugs block a molecule made by the bone that encourages breast cancer cells to grow into tumours in the bone. But before this existing drug can be repurposed, trials need to be carried out to see if the drug have the same effect in people. Read the Telegraph for more on these interesting findings.

Gabi

from Cancer Research UK – Science blog https://ift.tt/2rfaR0v

Spectacular! Don’t miss Venus and Jupiter

Photo above: View full image at EarthSky Community Photos. | Venus and Jupiter – bright in the western twilight sky, shortly after sunset – from our friend Dr Ski in the Philippines on November 20, 2019.

Wow! The sky’s two brightest planets – Venus and Jupiter – are now drawing closer together in the west after sunset. A conjunction between the two planets will happen on November 24, 2019. Venus, the brighter planet as seen in Earth’s sky, will pass a scant 1.4 degrees south of Jupiter. For reference, that’s about three moon-diameters, or about the width of your index finger held at arm’s length.

To maximize your enjoyment of these dazzling worlds – and especially if you’re in the Northern Hemisphere, where the two now appear low in the western twilight sky – be sure find an unobstructed horizon in the direction of sunset.

No matter where you are on Earth, Venus and Jupiter will be the first objects in the sky to pop out at dusk. They’ll follow the sun below your horizon as twilight gives way to dark.

The last Venus-Jupiter conjunction happened 10 months ago, on January 22, 2019, and the next one will occur on February 11, 2021. There will be no Venus-Jupiter conjunction in 2020.

So this is a relatively rare event. Don’t miss it.

See photos of Venus and Jupiter from the EarthSky community.

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

It should be grand viewing Venus and Jupiter around the time of their conjunction on November 24, 2019. After all, Venus and Jupiter rank as the 3rd-brightest and 4th-brightest heavenly bodies, respectively, after the sun and moon.

Watch for the young moon to fly by Jupiter, Venus and Saturn in late November 2019. Afterwards, Jupiter will sink downward and will disappear in the sun’s glare by around mid-December 2019. Venus, meanwhile, will climb upward, away from the sunset, to reign as a dazzling “evening star” throughout the first part of 2020.

We can all see Venus and Jupiter now. The key to seeing them is to go outside very soon after the sun goes down. The planets will quickly follow the sun below the western horizon. Here are the approximate setting times for Venus and Jupiter at various latitudes across the globe:

35 degrees north latitude
Venus and Jupiter set about 1 hour and 40 minutes after sunset

Equator (0 degrees latitude)
Venus and Jupiter set about 1 hour and 50 minutes after sunset

35 degrees south latitude
Venus and Jupiter set about 2 hours after sunset

Want more specific information? Click here for a recommended sky almanac.

You might catch Venus popping out into the evening twilight some 30 minutes (or less) after sunset, and then see Jupiter coming out 15 or so minutes after Venus first appears. The twosome should be pretty easy to see with the eye alone about one hour after sunset. But you can always use binoculars to spot these embracing worlds all the sooner after sundown.

View at EarthSky Community Photos. | Peter Lowenstein in Mutare, Zimbabwe, captured this image on November 18, 2019. He wrote: “A break in the weather after the onset of the rains provided a good Southern Hemisphere view of Jupiter (above) and bright Venus (below) getting closer together in the twilight sky. Antares is also faintly visible (lower left).” Thank you, Peter! The planets after sunset now are most easily viewed from Earth’s Southern Hemisphere, where the ecliptic – or path of the sun, moon and planets – makes a steep angle with the sunset horizon.

The interval between successive Venus-Jupiter conjunctions can be as little as 10 months or as long as 15 months. The mean interval is 13 months. Most of the time, there is one and only one Venus-Jupiter conjunction in one calendar year (though it is possible to have none). The year 2019 stands as an exception because two Venus-Jupiter conjunctions happen in one year. These two different conjunctions occur 10 months apart, allowing for a Venus-Jupiter conjunction on January 22, 2019, and then again on November 24, 2019.

It appears that similar Venus-Jupiter conjunctions recur in periods of about 24 years plus one week, whereby Venus and Jupiter return to nearly the same place relative to the sun, the stars of the zodiac, and the horizon. Hence, similar Venus-Jupiter conjunctions occurred 24 years ago (January 14 and November 19, 1995) and will again take place 24 years from now (January 29 and November 29, 2043):

1995 January 14 (morning sky)
1995 November 19 (evening sky)

2019 January 22 (morning sky)
2019 November 24 (evening sky)

2043 January 29 (morning sky)
2043 November 29 (evening sky)

Roughly midway between these twofold Venus-Jupiter conjunction years (1995, 2019 and 2043), we find two Venus-Jupiter conjunctions in 2008 – and then 24 years later, two Venus-Jupiter conjunctions in 2032.

2008 February 1 (morning sky)
2008 December 1 (evening sky)

2032 February 7 (morning sky)
2032 December 8 (evening sky)

The elongation (angular separation of the Venus-Jupiter conjunction from the sun) was 46 degrees west of the sun on January 22, 2019, and 26 degrees east of the sun on November 24, 2019. The elongations are more or less similar (within a few degrees) throughout the series: 1995, 2019 and 2043.

Interestingly, the elongations are similar – yet reversed – in these in-between years of 2008 and 2032. In 1995, 2019 and 2043, the year’s first conjunction in the morning sky showcases the conjunction near its maximum possible elongation from the sun (46 degrees west); yet, in the years 2008 and 2032, it’s the year’s second conjunction in the evening sky that presents the conjunction near maximum elongation (46 degrees east).

Want more details? Visit the Heavens-Above planet summary or enter your location and select Planets on the Heavens-Above home page. For an interactive online chart of the night sky for any location and time, visit Stellarium.

(Note: When Venus is near inferior conjunction, Venus can actually conjunct Jupiter three times in four months. Venus first meets up with Jupiter going prograde (eastward in front of the stars), a second time when going retrograde (westward in front of the stars), and finally a third time when going prograde (eastward) again. For our purposes, we’re calling this three-peat performance a “single” event. This special type of triple conjunction last happened in 2015 and will next take place in 2036.)

Because Venus and Jupiter beam as the third-brightest and fourth-brightest celestial bodies, respectively (after the sun and moon), Venus-Jupiter conjunctions are particularly spectacular and photogenic.

By the way, if you’re an early morning person, use the waning crescent moon to find the planets Mars and Mercury in the predawn/dawn sky right now, as shown on the sky chart below.

If you’re an early bird, waking up before the sun, then use the moon, the star Regulus and the star Spica to help you envision the ecliptic with the mind’s eye, and to find Mars and Mercury. Read more.

Bottom line: Witness the grand conjunction of Venus and Jupiter near the sunset point on the horizon as evening dusk deepens into nightfall. The conjunction itself is November 24, 2019. Any evening around then – especially the evenings before the conjunction – would be a wonderful time to view them.

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

Photo above: View full image at EarthSky Community Photos. | Venus and Jupiter – bright in the western twilight sky, shortly after sunset – from our friend Dr Ski in the Philippines on November 20, 2019.

Wow! The sky’s two brightest planets – Venus and Jupiter – are now drawing closer together in the west after sunset. A conjunction between the two planets will happen on November 24, 2019. Venus, the brighter planet as seen in Earth’s sky, will pass a scant 1.4 degrees south of Jupiter. For reference, that’s about three moon-diameters, or about the width of your index finger held at arm’s length.

To maximize your enjoyment of these dazzling worlds – and especially if you’re in the Northern Hemisphere, where the two now appear low in the western twilight sky – be sure find an unobstructed horizon in the direction of sunset.

No matter where you are on Earth, Venus and Jupiter will be the first objects in the sky to pop out at dusk. They’ll follow the sun below your horizon as twilight gives way to dark.

The last Venus-Jupiter conjunction happened 10 months ago, on January 22, 2019, and the next one will occur on February 11, 2021. There will be no Venus-Jupiter conjunction in 2020.

So this is a relatively rare event. Don’t miss it.

See photos of Venus and Jupiter from the EarthSky community.

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

It should be grand viewing Venus and Jupiter around the time of their conjunction on November 24, 2019. After all, Venus and Jupiter rank as the 3rd-brightest and 4th-brightest heavenly bodies, respectively, after the sun and moon.

Watch for the young moon to fly by Jupiter, Venus and Saturn in late November 2019. Afterwards, Jupiter will sink downward and will disappear in the sun’s glare by around mid-December 2019. Venus, meanwhile, will climb upward, away from the sunset, to reign as a dazzling “evening star” throughout the first part of 2020.

We can all see Venus and Jupiter now. The key to seeing them is to go outside very soon after the sun goes down. The planets will quickly follow the sun below the western horizon. Here are the approximate setting times for Venus and Jupiter at various latitudes across the globe:

35 degrees north latitude
Venus and Jupiter set about 1 hour and 40 minutes after sunset

Equator (0 degrees latitude)
Venus and Jupiter set about 1 hour and 50 minutes after sunset

35 degrees south latitude
Venus and Jupiter set about 2 hours after sunset

Want more specific information? Click here for a recommended sky almanac.

You might catch Venus popping out into the evening twilight some 30 minutes (or less) after sunset, and then see Jupiter coming out 15 or so minutes after Venus first appears. The twosome should be pretty easy to see with the eye alone about one hour after sunset. But you can always use binoculars to spot these embracing worlds all the sooner after sundown.

View at EarthSky Community Photos. | Peter Lowenstein in Mutare, Zimbabwe, captured this image on November 18, 2019. He wrote: “A break in the weather after the onset of the rains provided a good Southern Hemisphere view of Jupiter (above) and bright Venus (below) getting closer together in the twilight sky. Antares is also faintly visible (lower left).” Thank you, Peter! The planets after sunset now are most easily viewed from Earth’s Southern Hemisphere, where the ecliptic – or path of the sun, moon and planets – makes a steep angle with the sunset horizon.

The interval between successive Venus-Jupiter conjunctions can be as little as 10 months or as long as 15 months. The mean interval is 13 months. Most of the time, there is one and only one Venus-Jupiter conjunction in one calendar year (though it is possible to have none). The year 2019 stands as an exception because two Venus-Jupiter conjunctions happen in one year. These two different conjunctions occur 10 months apart, allowing for a Venus-Jupiter conjunction on January 22, 2019, and then again on November 24, 2019.

It appears that similar Venus-Jupiter conjunctions recur in periods of about 24 years plus one week, whereby Venus and Jupiter return to nearly the same place relative to the sun, the stars of the zodiac, and the horizon. Hence, similar Venus-Jupiter conjunctions occurred 24 years ago (January 14 and November 19, 1995) and will again take place 24 years from now (January 29 and November 29, 2043):

1995 January 14 (morning sky)
1995 November 19 (evening sky)

2019 January 22 (morning sky)
2019 November 24 (evening sky)

2043 January 29 (morning sky)
2043 November 29 (evening sky)

Roughly midway between these twofold Venus-Jupiter conjunction years (1995, 2019 and 2043), we find two Venus-Jupiter conjunctions in 2008 – and then 24 years later, two Venus-Jupiter conjunctions in 2032.

2008 February 1 (morning sky)
2008 December 1 (evening sky)

2032 February 7 (morning sky)
2032 December 8 (evening sky)

The elongation (angular separation of the Venus-Jupiter conjunction from the sun) was 46 degrees west of the sun on January 22, 2019, and 26 degrees east of the sun on November 24, 2019. The elongations are more or less similar (within a few degrees) throughout the series: 1995, 2019 and 2043.

Interestingly, the elongations are similar – yet reversed – in these in-between years of 2008 and 2032. In 1995, 2019 and 2043, the year’s first conjunction in the morning sky showcases the conjunction near its maximum possible elongation from the sun (46 degrees west); yet, in the years 2008 and 2032, it’s the year’s second conjunction in the evening sky that presents the conjunction near maximum elongation (46 degrees east).

Want more details? Visit the Heavens-Above planet summary or enter your location and select Planets on the Heavens-Above home page. For an interactive online chart of the night sky for any location and time, visit Stellarium.

(Note: When Venus is near inferior conjunction, Venus can actually conjunct Jupiter three times in four months. Venus first meets up with Jupiter going prograde (eastward in front of the stars), a second time when going retrograde (westward in front of the stars), and finally a third time when going prograde (eastward) again. For our purposes, we’re calling this three-peat performance a “single” event. This special type of triple conjunction last happened in 2015 and will next take place in 2036.)

Because Venus and Jupiter beam as the third-brightest and fourth-brightest celestial bodies, respectively (after the sun and moon), Venus-Jupiter conjunctions are particularly spectacular and photogenic.

By the way, if you’re an early morning person, use the waning crescent moon to find the planets Mars and Mercury in the predawn/dawn sky right now, as shown on the sky chart below.

If you’re an early bird, waking up before the sun, then use the moon, the star Regulus and the star Spica to help you envision the ecliptic with the mind’s eye, and to find Mars and Mercury. Read more.

Bottom line: Witness the grand conjunction of Venus and Jupiter near the sunset point on the horizon as evening dusk deepens into nightfall. The conjunction itself is November 24, 2019. Any evening around then – especially the evenings before the conjunction – would be a wonderful time to view them.

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Hamal is an ancient equinox star

These are star trails, and one of the brightest trails here is Alpha Arietis, or Hamal. To learn which one, click here, then click on the image you find. This neat image is via Herb Raab on Flickr.

Hamal – also known as Alpha Arietis – shines as the brightest star in the constellation Aries the Ram. This star and two others – Sheratan and Mesarthim – make up the Head of the Ram. Aries is small. But the compact pattern of these three stars makes Aries relatively easy to find. As seen from mid-northern latitudes, Hamal lights up the eastern sky on autumn evenings, shines high in the southern sky on winter evenings, and sits in the west on early spring evenings. It’s easily visible from Earth’s Southern Hemisphere, too … try using Stellarium to find Hamal from your exact location on the globe. As seen from the whole Earth, Hamal disappears from the night sky around April. It returns to the eastern sky before sunrise by late spring or early summer, to begin another cycle of visibility.

It’s fun to spot Hamal and its brother stars in the night sky. But this star also has a profound significance in the history of astronomy as an ancient equinox star.

In other words, in our modern era, if you could see the stars in daytime, you’d see the sun and Hamal in conjunction – lined up with one another, due north and south in right ascension – on or near April 24. But, long ago, they were in conjunction exactly at the March equinox.

Most people see the constellation Aries as three stars in a compact grouping. The stars are Hamal, Sheratan, and Mesarthim.

Nowadays, April 24 – the date of Hamal’s conjunction with the sun – is a little more than one month after the March equinox, which always takes place around March 20. This is the Northern Hemisphere’s spring equinox, and it’s a time of renewal throughout the northern half of Earth. So of course this time of year had significance to our ancestors, who were much more aware than we are of their dependence on the land and sky.

If you could backtrack some 2,500 years, you’d find the annual conjunction of the sun and Hamal happening on the March equinox. In fact, if you could backtrack 2,200 years, we’d also find the March equinox sun in conjunction with another star in Aries, Sheratan.

So you see that the location of the sun at the March equinox sun drifts in front of the stars. It moves westward in front of the backdrop constellations by about one degree (two sun diameters) every 72 years. This drifting is due to a well-known motion of Earth called precession, or sometimes the precession of the equinoxes.

The March equinox sun shone in front of the constellation Aries from about 2,000 to 100 BCE. At present, the sun shines in front of the constellation Pisces on the March equinox.

Even so, many people pay homage to the Ram and still refer to the March equinox point as the First Point of Aries.

Sky chart of the constellation Aries the Ram

Nowadays the sun passes in front of the constellation Aries from about April 19 to May 13. Click here for a larger chart

Bottom line: The star Hamal is the brightest star in Aries the Ram. Thousands of years ago, the sun was in conjunction – or aligned north and south – with this star at the time of the March equinox.

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These are star trails, and one of the brightest trails here is Alpha Arietis, or Hamal. To learn which one, click here, then click on the image you find. This neat image is via Herb Raab on Flickr.

Hamal – also known as Alpha Arietis – shines as the brightest star in the constellation Aries the Ram. This star and two others – Sheratan and Mesarthim – make up the Head of the Ram. Aries is small. But the compact pattern of these three stars makes Aries relatively easy to find. As seen from mid-northern latitudes, Hamal lights up the eastern sky on autumn evenings, shines high in the southern sky on winter evenings, and sits in the west on early spring evenings. It’s easily visible from Earth’s Southern Hemisphere, too … try using Stellarium to find Hamal from your exact location on the globe. As seen from the whole Earth, Hamal disappears from the night sky around April. It returns to the eastern sky before sunrise by late spring or early summer, to begin another cycle of visibility.

It’s fun to spot Hamal and its brother stars in the night sky. But this star also has a profound significance in the history of astronomy as an ancient equinox star.

In other words, in our modern era, if you could see the stars in daytime, you’d see the sun and Hamal in conjunction – lined up with one another, due north and south in right ascension – on or near April 24. But, long ago, they were in conjunction exactly at the March equinox.

Most people see the constellation Aries as three stars in a compact grouping. The stars are Hamal, Sheratan, and Mesarthim.

Nowadays, April 24 – the date of Hamal’s conjunction with the sun – is a little more than one month after the March equinox, which always takes place around March 20. This is the Northern Hemisphere’s spring equinox, and it’s a time of renewal throughout the northern half of Earth. So of course this time of year had significance to our ancestors, who were much more aware than we are of their dependence on the land and sky.

If you could backtrack some 2,500 years, you’d find the annual conjunction of the sun and Hamal happening on the March equinox. In fact, if you could backtrack 2,200 years, we’d also find the March equinox sun in conjunction with another star in Aries, Sheratan.

So you see that the location of the sun at the March equinox sun drifts in front of the stars. It moves westward in front of the backdrop constellations by about one degree (two sun diameters) every 72 years. This drifting is due to a well-known motion of Earth called precession, or sometimes the precession of the equinoxes.

The March equinox sun shone in front of the constellation Aries from about 2,000 to 100 BCE. At present, the sun shines in front of the constellation Pisces on the March equinox.

Even so, many people pay homage to the Ram and still refer to the March equinox point as the First Point of Aries.

Sky chart of the constellation Aries the Ram

Nowadays the sun passes in front of the constellation Aries from about April 19 to May 13. Click here for a larger chart

Bottom line: The star Hamal is the brightest star in Aries the Ram. Thousands of years ago, the sun was in conjunction – or aligned north and south – with this star at the time of the March equinox.

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Bizarre Tully Monster fossil is still a mystery

Artist’s illustration of how the Tully Monster would have looked. Image via PaleoEquii/Wikipedia, CC BY-SA/Phys.org.

Evolution can be very weird sometimes, producing creatures that are so bizarre-looking, you might think they must be aliens. Such is the the case with the Tully Monster, a marine animal that kind of looked like a giant slug and lived about 300 million years ago. Now, a new study shows that this ancient creature may be even more mysterious than previously thought.

New peer-reviewed findings were published in the October 2019 issue of Proceedings of the Royal Society B: Biological Sciences.

The famed Tully Monster fossil – formally known as Tullimonstrum – was first discovered at Mazon Creek in in Illinois in the 1950s. Ever since it was found, scientists have been unable to agree on whether Tully was a vertebrate (with a backbone) or an invertebrate (no backbone). A previous report in 2016 claimed that Tully must be a vertebrate.

The once-living creature is indeed one of the strangest ever discovered, with a slug-like body and long thin appendage ending in a claw-like structure with two rows of conical teeth. Its eyes are at the end of long thin stalks, or rigid bars, like something out of a science fiction movie. It also had a vertical tail fin and a long, narrow dorsal fin. The Tully Monster wasn’t too big though, growing up to 14 inches (35 cm) long. As paleontologist Victoria McCoy at the University of Leicester put it:

I would rank the Tully Monster just about at the top of the scale of weirdness.

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Another reconstruction of the Tully Monster. Image via Sean McMahon via EurekAlert/Scientific American.

But now the new findings from Chris Rogers at University College Cork are challenging that consensus.

One of the main pieces of evidence that led to Tully previously being declared a vertebrate was that its eyes contained pigment granules called melanosomes, which are arranged by shape and size in the same way as those in vertebrate eyes.

But the new research has called that into question, pointing out that some invertebrates – such as octopus and squid – do have melanosomes that are similar to the ones found in Tully.

So how did Rogers and his team determine this?

They used a kind of particle accelerator called a synchrotron radiation lightsource, at Stanford University in California, which can examine the chemical makeup of both fossils and living animals. According to Rogers:

To do this, we used a type of particle accelerator called the Stanford Synchrotron Radiation Lightsource (SSRL) located at Stanford University in California. This allowed us to explore the chemical makeup of samples from fossils and from animals living today. The synchrotron bombards specimens with intense bursts of radiation to “excite” the elements within them. When excited, each element releases X-rays with a specific signature. By detecting the emitted X-ray signatures, we can tell what elements were excited and ultimately what the specimen we’re interested in is made of.

The Tully Monster (Tullimonstrum) fossil. Image via Ghedoghedo/Wikimedia, CC BY-SA/The Conversation.

When they looked at samples of modern vertebrates and invertebrates, they found something interesting. The eyes of modern vertebrates have a higher zinc to copper ratio than modern invertebrates.

That same pattern of zinc and copper was then also found in fossils from Mazon Creek, where the Tully fossil had been discovered. So the researchers then examined the eyes of the Tully fossil itself. The zinc to copper ratio was found to be more similar to that of invertebrates, challenging the previous conclusion that Tully was a vertebrate.

But there was also another twist. The copper in Tully’s eyes was a different type of copper from that normally found in the eyes of both vertebrates and invertebrates, confusing the issue even further.

Chris Rogers, Postdoctoral Researcher in Palaeobiology at University College Cork. Image via The Conversation.

In light of these findings, the debate over Tully still continues. While new evidence suggests it was an invertebrate, it isn’t a slam-dunk case yet, either. Only further testing and analysis will help to finally determine what kind of species Tully really was.

Bottom line: The Tully Monster – one of the most bizarre fossils ever found – is still a mystery as to whether it was a vertebrate or an invertebrate, according to a new study.

Source: Synchrotron X-ray absorption spectroscopy of melanosomes in vertebrates and cephalopods: implications for the affinity of Tullimonstrum

Via The Conversation

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Artist’s illustration of how the Tully Monster would have looked. Image via PaleoEquii/Wikipedia, CC BY-SA/Phys.org.

Evolution can be very weird sometimes, producing creatures that are so bizarre-looking, you might think they must be aliens. Such is the the case with the Tully Monster, a marine animal that kind of looked like a giant slug and lived about 300 million years ago. Now, a new study shows that this ancient creature may be even more mysterious than previously thought.

New peer-reviewed findings were published in the October 2019 issue of Proceedings of the Royal Society B: Biological Sciences.

The famed Tully Monster fossil – formally known as Tullimonstrum – was first discovered at Mazon Creek in in Illinois in the 1950s. Ever since it was found, scientists have been unable to agree on whether Tully was a vertebrate (with a backbone) or an invertebrate (no backbone). A previous report in 2016 claimed that Tully must be a vertebrate.

The once-living creature is indeed one of the strangest ever discovered, with a slug-like body and long thin appendage ending in a claw-like structure with two rows of conical teeth. Its eyes are at the end of long thin stalks, or rigid bars, like something out of a science fiction movie. It also had a vertical tail fin and a long, narrow dorsal fin. The Tully Monster wasn’t too big though, growing up to 14 inches (35 cm) long. As paleontologist Victoria McCoy at the University of Leicester put it:

I would rank the Tully Monster just about at the top of the scale of weirdness.

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

Another reconstruction of the Tully Monster. Image via Sean McMahon via EurekAlert/Scientific American.

But now the new findings from Chris Rogers at University College Cork are challenging that consensus.

One of the main pieces of evidence that led to Tully previously being declared a vertebrate was that its eyes contained pigment granules called melanosomes, which are arranged by shape and size in the same way as those in vertebrate eyes.

But the new research has called that into question, pointing out that some invertebrates – such as octopus and squid – do have melanosomes that are similar to the ones found in Tully.

So how did Rogers and his team determine this?

They used a kind of particle accelerator called a synchrotron radiation lightsource, at Stanford University in California, which can examine the chemical makeup of both fossils and living animals. According to Rogers:

To do this, we used a type of particle accelerator called the Stanford Synchrotron Radiation Lightsource (SSRL) located at Stanford University in California. This allowed us to explore the chemical makeup of samples from fossils and from animals living today. The synchrotron bombards specimens with intense bursts of radiation to “excite” the elements within them. When excited, each element releases X-rays with a specific signature. By detecting the emitted X-ray signatures, we can tell what elements were excited and ultimately what the specimen we’re interested in is made of.

The Tully Monster (Tullimonstrum) fossil. Image via Ghedoghedo/Wikimedia, CC BY-SA/The Conversation.

When they looked at samples of modern vertebrates and invertebrates, they found something interesting. The eyes of modern vertebrates have a higher zinc to copper ratio than modern invertebrates.

That same pattern of zinc and copper was then also found in fossils from Mazon Creek, where the Tully fossil had been discovered. So the researchers then examined the eyes of the Tully fossil itself. The zinc to copper ratio was found to be more similar to that of invertebrates, challenging the previous conclusion that Tully was a vertebrate.

But there was also another twist. The copper in Tully’s eyes was a different type of copper from that normally found in the eyes of both vertebrates and invertebrates, confusing the issue even further.

Chris Rogers, Postdoctoral Researcher in Palaeobiology at University College Cork. Image via The Conversation.

In light of these findings, the debate over Tully still continues. While new evidence suggests it was an invertebrate, it isn’t a slam-dunk case yet, either. Only further testing and analysis will help to finally determine what kind of species Tully really was.

Bottom line: The Tully Monster – one of the most bizarre fossils ever found – is still a mystery as to whether it was a vertebrate or an invertebrate, according to a new study.

Source: Synchrotron X-ray absorption spectroscopy of melanosomes in vertebrates and cephalopods: implications for the affinity of Tullimonstrum

Via The Conversation

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Arctic ice loss exposes sea mammals to deadly virus

Steller sea lions. Image via NOAA Fisheries, Polar Ecosystems Program/UC Davis.

A new study has linked the decline in Arctic sea ice to the emergence of a deadly virus that could threaten marine mammals in the North Pacific. The researchers say melting sea ice is connecting marine mammals that were formerly separated by ice, opening pathways of disease transmission.

The virus, phocine distemper virus (PDV, also called phocine morbillivirus), which killed thousands of European harbor seals in the North Atlantic in 2002, was identified in northern sea otters in Alaska in 2004, raising questions about when and how the virus reached them.

In recent decades, sea ice in the Arctic Ocean has been melting faster than it re-freezes in winter. As the ice melts, the virus is on the move, said the researchers. Their 15-year study, published November 7, 2019, in the peer-reviewed journal Scientific Reports, suggests that the radical reshaping of sea ice has opened pathways for contact between Arctic and sub-Arctic seals that was previously impossible. This allowed for the virus’ introduction into the Northern Pacific Ocean.

Tracey Goldstein, of University of California Davis School of Veterinary Medicine, is a study co-author She said in a statement:

The loss of sea ice is leading marine wildlife to seek and forage in new habitats and removing that physical barrier, allowing for new pathways for them to move. As animals move and come in contact with other species, they carry opportunities to introduce and transmit new infectious disease, with potentially devastating impacts.

For the study, tresearchers sampled marine mammals – including northern fur seals, Steller sea lions and northern sea otters – for PDV exposure and infection from 2001 to 2016, from Southeast Alaska to Russia along the Aleutian Islands and the Bering, Chukchi and Beaufort seas.

Satellite data helped the researchers link animal movement and risk factor data, in order to demonstrate that exposed animals have the potential to carry phocine distemper virus long distances.

The scientists identified widespread infection and exposure to the virus across the North Pacific Ocean beginning in 2003, with a second peak of exposure and infection in 2009. These peaks coincided with reductions in Arctic sea ice extent, they said.

University of Nebraska’s Elizabeth VanWormer is the study lead author. She said:

As sea ice continues its melting trend, the opportunities for this virus and other pathogens to cross between North Atlantic and North Pacific marine mammals may become more common.

Bottom line: A new study suggests declining Arctic sea is contributing to the spread of a deadly virus among marine mammals.

Via University of California Davis

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Steller sea lions. Image via NOAA Fisheries, Polar Ecosystems Program/UC Davis.

A new study has linked the decline in Arctic sea ice to the emergence of a deadly virus that could threaten marine mammals in the North Pacific. The researchers say melting sea ice is connecting marine mammals that were formerly separated by ice, opening pathways of disease transmission.

The virus, phocine distemper virus (PDV, also called phocine morbillivirus), which killed thousands of European harbor seals in the North Atlantic in 2002, was identified in northern sea otters in Alaska in 2004, raising questions about when and how the virus reached them.

In recent decades, sea ice in the Arctic Ocean has been melting faster than it re-freezes in winter. As the ice melts, the virus is on the move, said the researchers. Their 15-year study, published November 7, 2019, in the peer-reviewed journal Scientific Reports, suggests that the radical reshaping of sea ice has opened pathways for contact between Arctic and sub-Arctic seals that was previously impossible. This allowed for the virus’ introduction into the Northern Pacific Ocean.

Tracey Goldstein, of University of California Davis School of Veterinary Medicine, is a study co-author She said in a statement:

The loss of sea ice is leading marine wildlife to seek and forage in new habitats and removing that physical barrier, allowing for new pathways for them to move. As animals move and come in contact with other species, they carry opportunities to introduce and transmit new infectious disease, with potentially devastating impacts.

For the study, tresearchers sampled marine mammals – including northern fur seals, Steller sea lions and northern sea otters – for PDV exposure and infection from 2001 to 2016, from Southeast Alaska to Russia along the Aleutian Islands and the Bering, Chukchi and Beaufort seas.

Satellite data helped the researchers link animal movement and risk factor data, in order to demonstrate that exposed animals have the potential to carry phocine distemper virus long distances.

The scientists identified widespread infection and exposure to the virus across the North Pacific Ocean beginning in 2003, with a second peak of exposure and infection in 2009. These peaks coincided with reductions in Arctic sea ice extent, they said.

University of Nebraska’s Elizabeth VanWormer is the study lead author. She said:

As sea ice continues its melting trend, the opportunities for this virus and other pathogens to cross between North Atlantic and North Pacific marine mammals may become more common.

Bottom line: A new study suggests declining Arctic sea is contributing to the spread of a deadly virus among marine mammals.

Via University of California Davis

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Old moon to pass Spica, Mars, Mercury

Are you an early morning person, up and about during the predawn/dawn hours? If so, let the old waning crescent moon serve as your guide to the morning lineup of celestial lights: Spica, the constellation Virgo‘s brightest star, plus the planets Mars and Mercury.

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

If you’re not one to get up early – or even if you are – pay attention to the Venus-Jupiter show in the southwest sky at dusk/nightfall. These two brilliant worlds reside quite close together on the sky’s dome now, but will snuggle up even most closely on their conjunction date: November 24, 2019. Read more.

On the morning of November 22, as seen from around the world, the lit side of the moon points at this string of lights, with Spica reigning at top, Mercury at bottom and Mars in between. In terms of brilliance, Mercury is the brightest of the threesome, followed by 1st-magnitude Spica and then 2nd-magnitude Mars.

At present, Spica is about twice as bright as Mars; whereas Mercury is more than twice Spica’s brightness. That doesn’t necessarily mean Mercury will be the easiest of the bunch to see, however. Mercury will sit the lowest in the sky and closest to the glare of the sun.

It’ll be easier to observe the morning attraction at northerly latitudes than at southerly latitudes. At temperate latitudes in the Southern Hemisphere, these heavenly bodies rise quite close to sunrise.

We give the approximate rising times of Spica, Mars and Mercury for various latitudes:

35 degrees north latitude:
Spica rises 2 3/4 hours before the sun
Mars rises 2 1/4 hours before the sun
Mercury rises 1 1/2 hours before the sun

Equator (0 degrees latitude):
Spica rises 2 1/3 hours before the sun
Mars rises 1 3/4 hours before the sun
Mercury rises 1 1/10 hours before the sun

35 degrees south latitude:
Spica rises 2 hours before the sun
Mars rises 1 1/3 hours before the sun
Mercury rises 3/4 hour before the sun

Want more specific information? Click here for a recommended sky almanac.

Arcturus, the brightest star to adorn the eastern morning sky, shines to the upper left of the celestial line-up at mid-northern latitudes. At the equator (0 degrees latitude), Arcturus is seen to the left (not the upper left) of Mars and Mercury. At temperate latitudes in the Southern Hemisphere, Arcturus is not visible because it rises around or after sunrise in that part of the world.

Day by day, watch the waning (shrinking) lunar crescent sink closer and closer to the sunrise point on the horizon. The moon will bypass Spica on or near November 23, pair up with Mars around November 24, and then meet up with Mercury on November 25. New moon will come on November 26 – at which juncture, the moon will pass more or less in front of the sun, to transition out of the morning sky and into the evening sky.

Visit Sunrise Sunset Calendars to find out when the moon rises into your sky, remembering to check the moonrise and moonset box.

For the Northern Hemisphere, this morning apparition of Mercury counts as a particularly good one, so Mercury should be fairly easy to see with the eye alone for the next several weeks. What’s more, Mercury is brightening by the day. On November 23, Mercury will match Arcturus in brightness; and by the month’s end, Mercury will be about 1 1/2 times brighter than Arcturus.

At temperate latitudes in the Southern Hemisphere, you’ll probably need binoculars to spot Mercury. At southerly latitudes, Mercury rises a short while before the sun and sits in the harsh glare of morning twilight.

Bottom line: Enjoy the morning spectacle over the next several mornings, as the waning crescent moon sweeps by the star Spica and then the planets Mars and Mercury.

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

Are you an early morning person, up and about during the predawn/dawn hours? If so, let the old waning crescent moon serve as your guide to the morning lineup of celestial lights: Spica, the constellation Virgo‘s brightest star, plus the planets Mars and Mercury.

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

If you’re not one to get up early – or even if you are – pay attention to the Venus-Jupiter show in the southwest sky at dusk/nightfall. These two brilliant worlds reside quite close together on the sky’s dome now, but will snuggle up even most closely on their conjunction date: November 24, 2019. Read more.

On the morning of November 22, as seen from around the world, the lit side of the moon points at this string of lights, with Spica reigning at top, Mercury at bottom and Mars in between. In terms of brilliance, Mercury is the brightest of the threesome, followed by 1st-magnitude Spica and then 2nd-magnitude Mars.

At present, Spica is about twice as bright as Mars; whereas Mercury is more than twice Spica’s brightness. That doesn’t necessarily mean Mercury will be the easiest of the bunch to see, however. Mercury will sit the lowest in the sky and closest to the glare of the sun.

It’ll be easier to observe the morning attraction at northerly latitudes than at southerly latitudes. At temperate latitudes in the Southern Hemisphere, these heavenly bodies rise quite close to sunrise.

We give the approximate rising times of Spica, Mars and Mercury for various latitudes:

35 degrees north latitude:
Spica rises 2 3/4 hours before the sun
Mars rises 2 1/4 hours before the sun
Mercury rises 1 1/2 hours before the sun

Equator (0 degrees latitude):
Spica rises 2 1/3 hours before the sun
Mars rises 1 3/4 hours before the sun
Mercury rises 1 1/10 hours before the sun

35 degrees south latitude:
Spica rises 2 hours before the sun
Mars rises 1 1/3 hours before the sun
Mercury rises 3/4 hour before the sun

Want more specific information? Click here for a recommended sky almanac.

Arcturus, the brightest star to adorn the eastern morning sky, shines to the upper left of the celestial line-up at mid-northern latitudes. At the equator (0 degrees latitude), Arcturus is seen to the left (not the upper left) of Mars and Mercury. At temperate latitudes in the Southern Hemisphere, Arcturus is not visible because it rises around or after sunrise in that part of the world.

Day by day, watch the waning (shrinking) lunar crescent sink closer and closer to the sunrise point on the horizon. The moon will bypass Spica on or near November 23, pair up with Mars around November 24, and then meet up with Mercury on November 25. New moon will come on November 26 – at which juncture, the moon will pass more or less in front of the sun, to transition out of the morning sky and into the evening sky.

Visit Sunrise Sunset Calendars to find out when the moon rises into your sky, remembering to check the moonrise and moonset box.

For the Northern Hemisphere, this morning apparition of Mercury counts as a particularly good one, so Mercury should be fairly easy to see with the eye alone for the next several weeks. What’s more, Mercury is brightening by the day. On November 23, Mercury will match Arcturus in brightness; and by the month’s end, Mercury will be about 1 1/2 times brighter than Arcturus.

At temperate latitudes in the Southern Hemisphere, you’ll probably need binoculars to spot Mercury. At southerly latitudes, Mercury rises a short while before the sun and sits in the harsh glare of morning twilight.

Bottom line: Enjoy the morning spectacle over the next several mornings, as the waning crescent moon sweeps by the star Spica and then the planets Mars and Mercury.

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