What is an eclipse season?

View larger. | EarthSky community member Beverley Sinclair captured this beautiful view of a total solar eclipse outside Charleston, South Carolina, on August 21, 2017, and wrote: “The skies were very cloudy leading up to totality but, miraculously, slowly cleared as totality approached. This photo shows the diamond ring and Bailey’s beads.” Thank you, Beverley!

An eclipse season is a 35-day period during which it’s possible for an eclipse to take place. There are four to seven eclipses every calendar year. Typically, there are two eclipse seasons. They recur in cycles of 173.3 days (somewhat shy of six calendar months). Each eclipse season has two or three eclipses. In some years, it’s possible to have a third eclipse season straddling into the previous or following year; that’s how we get to seven eclipses in some years.

We started 2020 in the midst of an eclipse season. There’d been a solar eclipse on December 26, 2019, and there was a lunar eclipse on January 10, 2020.

The next eclipse season starts June 5, 2020. The eclipse season of June and July 2020 will feature three eclipses: a lunar eclipse on June 5-6, a solar eclipse on June 21, and the third eclipse of that eclipse season, a lunar eclipse, on July 4-5. That eclipse season – June and July 2020 – will be the last eclipse season with three eclipses until the year 2029.

We’ll also end 2020 with an eclipse season: a lunar eclipse on November 29-30 and a solar eclipse on December 14.

Here are some words you need to know to understand eclipse seasons: lunar nodes and ecliptic. The ecliptic is the plane of the Earth’s orbit around the sun. A lunar node is the point where, in its monthly orbit of Earth, the moon’s orbit intersects that plane. An eclipse season is when – from Earth’s perspective – the sun is close enough to a lunar node to allow an eclipse to take place. If the sun is close to a lunar node at full moon, we see a lunar eclipse. If the sun is close to a lunar node at new moon, we see a solar eclipse.

To put it another way, if the moon turns new or full in close concert with the moon’s crossing of one of its nodes, then an eclipse is not only possible – but inevitable.

Lunar nodes are where the moon’s orbit cuts through the ecliptic, or Earth-sun plane. When these nodes point directly at the sun, it marks the midpoint of an approximate 35-day eclipse season. The middle of an eclipse season occurred on December 30, 2019. The middle of an eclipse season will occur on June 20, 2020. Image via Go Science Go.

Given that the lunar month (period of time between successive new moons or successive full moons) is about 29.5 days long, a minimum of two eclipses (one solar and one lunar, in either order) happens in one eclipse season. A maximum of three eclipses is possible (either lunar/solar/lunar, or solar/lunar/solar), though the first eclipse of the eclipse season has to come quite early to allow for a third eclipse near the end.

If there are seven eclipses in one calendar year, there are a few possibilities. The first one belongs to an eclipse season that started in the previous year – and/or the seventh eclipse belongs to an eclipse season that ends in the following year. It’s rare for seven eclipses to occur in one calendar year, however. It last happened in the year 1982, and will next occur in the year 2038.

View at EarthSky Community Photos. | Progression into and out of the annular eclipse on December 26, 2019, from Tumon Bay, Guam. Eliot Herman reported: “It was a beautiful day in Guam to observe the eclipse mostly clear blue skies with a little marine haze on the coast. These images were captured with a Questar telescope and a Nikon D850 camera using a Baader solar filter.” Thank you, Eliot!

Any lunar eclipse that comes early, or late, in an eclipse season finds the full moon missing the Earth’s umbra (inner dark shadow), and passing through the penumbra (outer faint shadow) instead.

A solar eclipse can happen only at new moon. A lunar eclipse can happen only at full moon. Additionally – for an eclipse to occur – the new moon or full moon has to take place within an eclipse season. Otherwise, the new moon passes too far north, or south, of the sun for a solar eclipse to take place, and the full moon sweeps too far north, or south, of the Earth’s shadow for a lunar eclipse to take place.

Eclipses are all about alignments. In a solar eclipse, the sun, moon and Earth line up, with the moon in the middle. Image via NASA.

In a lunar eclipse, the sun, Earth and moon line up, with the Earth in the middle. Image via NASA.

Why do we have eclipse seasons?

There are many cycles in the heavens. An eclipse season is just one of these many celestial cycles.

Consider that if the moon orbited Earth on the same plane that the Earth orbits the sun, then we’d have a solar eclipse at every new moon, and a lunar eclipse at every full moon.

But – in reality – the moon’s orbit is inclined by 5 degrees to the ecliptic (Earth’s orbital plane), so most of the time the new moon or full moon swings too far north, or south, of the ecliptic for an eclipse to take place. For instance, in the year 2020, we will have 12 new moons and 13 full moons, but only 2 solar eclipses and 4 lunar eclipses (all of the lunar eclipses in 2020, unfortunately, will be faint and hard-to-see penumbral lunar eclipses).

In the year 2020, there are 12 new moons and 13 full moons. A = annular solar eclipse, T = total solar eclipse, and n = penumbral lunar elcipse. Moon phases via Astropixels.

Twice every month, as the moon circles Earth in its orbit, the moon crosses the ecliptic (Earth’s orbital plane) at points called nodes. If the moon is going from south to north, it’s called the moon’s ascending node, and if the moon is moving from north to south, it’s called the moon’s descending node. The moon was last at its descending node on December 26, 2019, and will reach its ascending node on January 9, 2020.

Read more: Node passages of the Moon: 2001 to 2100

Whenever the lunar nodes point directly at the sun, that momentous event marks the middle of the eclipse season. The alignment of the moon, sun and Earth is most exact when an eclipse happens at the middle of an eclipse season, and the least so when an eclipse occurs at the start, or the end, of an eclipse season. Any lunar eclipse happening early or late in the eclipse season presents a penumbral lunar eclipse, whereas any solar eclipse happening early or late in the eclipse season features a skimpy partial eclipse of the sun.

This year, 2020, the middles of the eclipse seasons fall on June 20, 2020, and December 11, 2020.

Middle of eclipse season: June 20, 2020
First eclipse (lunar): June 5, 2020
Second eclipse (solar): June 21, 2020
Third eclipse (lunar): July 5, 2020

Middle of eclipse season: December 11, 2020
First eclipse (lunar): November 30, 2020
Second eclipse (solar): December 14, 2020

The plane of the moon’s orbit is inclined at 5 degrees to the plane of Earth’s orbit around the sun (the ecliptic). In this diagram, however, the ecliptic is portrayed as the sun’s apparent annual path in front of the constellations of the zodiac. The moon’s orbit intersects the ecliptic at two points called nodes (labeled here as N1 and N2). It’s the middle of the eclipse season whenever this line of nodes points directly at the sun. In the above diagram, the line of nodes does not point at the sun.

Bottom line: An eclipse season is when – from Earth’s perspective – the sun is close enough to a lunar node to allow an eclipse to take place. If the sun is close to a node at full moon, we see a lunar eclipse. If the sun is close to a node at new moon, we see a solar eclipse. A minimum of two eclipses (one solar and one lunar, in either order) happens in one eclipse season. A maximum of three eclipses is possible (either lunar/solar/lunar, or solar/lunar/solar).

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View larger. | EarthSky community member Beverley Sinclair captured this beautiful view of a total solar eclipse outside Charleston, South Carolina, on August 21, 2017, and wrote: “The skies were very cloudy leading up to totality but, miraculously, slowly cleared as totality approached. This photo shows the diamond ring and Bailey’s beads.” Thank you, Beverley!

An eclipse season is a 35-day period during which it’s possible for an eclipse to take place. There are four to seven eclipses every calendar year. Typically, there are two eclipse seasons. They recur in cycles of 173.3 days (somewhat shy of six calendar months). Each eclipse season has two or three eclipses. In some years, it’s possible to have a third eclipse season straddling into the previous or following year; that’s how we get to seven eclipses in some years.

We started 2020 in the midst of an eclipse season. There’d been a solar eclipse on December 26, 2019, and there was a lunar eclipse on January 10, 2020.

The next eclipse season starts June 5, 2020. The eclipse season of June and July 2020 will feature three eclipses: a lunar eclipse on June 5-6, a solar eclipse on June 21, and the third eclipse of that eclipse season, a lunar eclipse, on July 4-5. That eclipse season – June and July 2020 – will be the last eclipse season with three eclipses until the year 2029.

We’ll also end 2020 with an eclipse season: a lunar eclipse on November 29-30 and a solar eclipse on December 14.

Here are some words you need to know to understand eclipse seasons: lunar nodes and ecliptic. The ecliptic is the plane of the Earth’s orbit around the sun. A lunar node is the point where, in its monthly orbit of Earth, the moon’s orbit intersects that plane. An eclipse season is when – from Earth’s perspective – the sun is close enough to a lunar node to allow an eclipse to take place. If the sun is close to a lunar node at full moon, we see a lunar eclipse. If the sun is close to a lunar node at new moon, we see a solar eclipse.

To put it another way, if the moon turns new or full in close concert with the moon’s crossing of one of its nodes, then an eclipse is not only possible – but inevitable.

Lunar nodes are where the moon’s orbit cuts through the ecliptic, or Earth-sun plane. When these nodes point directly at the sun, it marks the midpoint of an approximate 35-day eclipse season. The middle of an eclipse season occurred on December 30, 2019. The middle of an eclipse season will occur on June 20, 2020. Image via Go Science Go.

Given that the lunar month (period of time between successive new moons or successive full moons) is about 29.5 days long, a minimum of two eclipses (one solar and one lunar, in either order) happens in one eclipse season. A maximum of three eclipses is possible (either lunar/solar/lunar, or solar/lunar/solar), though the first eclipse of the eclipse season has to come quite early to allow for a third eclipse near the end.

If there are seven eclipses in one calendar year, there are a few possibilities. The first one belongs to an eclipse season that started in the previous year – and/or the seventh eclipse belongs to an eclipse season that ends in the following year. It’s rare for seven eclipses to occur in one calendar year, however. It last happened in the year 1982, and will next occur in the year 2038.

View at EarthSky Community Photos. | Progression into and out of the annular eclipse on December 26, 2019, from Tumon Bay, Guam. Eliot Herman reported: “It was a beautiful day in Guam to observe the eclipse mostly clear blue skies with a little marine haze on the coast. These images were captured with a Questar telescope and a Nikon D850 camera using a Baader solar filter.” Thank you, Eliot!

Any lunar eclipse that comes early, or late, in an eclipse season finds the full moon missing the Earth’s umbra (inner dark shadow), and passing through the penumbra (outer faint shadow) instead.

A solar eclipse can happen only at new moon. A lunar eclipse can happen only at full moon. Additionally – for an eclipse to occur – the new moon or full moon has to take place within an eclipse season. Otherwise, the new moon passes too far north, or south, of the sun for a solar eclipse to take place, and the full moon sweeps too far north, or south, of the Earth’s shadow for a lunar eclipse to take place.

Eclipses are all about alignments. In a solar eclipse, the sun, moon and Earth line up, with the moon in the middle. Image via NASA.

In a lunar eclipse, the sun, Earth and moon line up, with the Earth in the middle. Image via NASA.

Why do we have eclipse seasons?

There are many cycles in the heavens. An eclipse season is just one of these many celestial cycles.

Consider that if the moon orbited Earth on the same plane that the Earth orbits the sun, then we’d have a solar eclipse at every new moon, and a lunar eclipse at every full moon.

But – in reality – the moon’s orbit is inclined by 5 degrees to the ecliptic (Earth’s orbital plane), so most of the time the new moon or full moon swings too far north, or south, of the ecliptic for an eclipse to take place. For instance, in the year 2020, we will have 12 new moons and 13 full moons, but only 2 solar eclipses and 4 lunar eclipses (all of the lunar eclipses in 2020, unfortunately, will be faint and hard-to-see penumbral lunar eclipses).

In the year 2020, there are 12 new moons and 13 full moons. A = annular solar eclipse, T = total solar eclipse, and n = penumbral lunar elcipse. Moon phases via Astropixels.

Twice every month, as the moon circles Earth in its orbit, the moon crosses the ecliptic (Earth’s orbital plane) at points called nodes. If the moon is going from south to north, it’s called the moon’s ascending node, and if the moon is moving from north to south, it’s called the moon’s descending node. The moon was last at its descending node on December 26, 2019, and will reach its ascending node on January 9, 2020.

Read more: Node passages of the Moon: 2001 to 2100

Whenever the lunar nodes point directly at the sun, that momentous event marks the middle of the eclipse season. The alignment of the moon, sun and Earth is most exact when an eclipse happens at the middle of an eclipse season, and the least so when an eclipse occurs at the start, or the end, of an eclipse season. Any lunar eclipse happening early or late in the eclipse season presents a penumbral lunar eclipse, whereas any solar eclipse happening early or late in the eclipse season features a skimpy partial eclipse of the sun.

This year, 2020, the middles of the eclipse seasons fall on June 20, 2020, and December 11, 2020.

Middle of eclipse season: June 20, 2020
First eclipse (lunar): June 5, 2020
Second eclipse (solar): June 21, 2020
Third eclipse (lunar): July 5, 2020

Middle of eclipse season: December 11, 2020
First eclipse (lunar): November 30, 2020
Second eclipse (solar): December 14, 2020

The plane of the moon’s orbit is inclined at 5 degrees to the plane of Earth’s orbit around the sun (the ecliptic). In this diagram, however, the ecliptic is portrayed as the sun’s apparent annual path in front of the constellations of the zodiac. The moon’s orbit intersects the ecliptic at two points called nodes (labeled here as N1 and N2). It’s the middle of the eclipse season whenever this line of nodes points directly at the sun. In the above diagram, the line of nodes does not point at the sun.

Bottom line: An eclipse season is when – from Earth’s perspective – the sun is close enough to a lunar node to allow an eclipse to take place. If the sun is close to a node at full moon, we see a lunar eclipse. If the sun is close to a node at new moon, we see a solar eclipse. A minimum of two eclipses (one solar and one lunar, in either order) happens in one eclipse season. A maximum of three eclipses is possible (either lunar/solar/lunar, or solar/lunar/solar).

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How are zoo animals handling the coronavirus shutdown?

A Californian sea lion swims behind empty seats in its enclosure at a zoo in Berlin, April 4 2020. Image via EPA-EFE/ Clemens Bilan/ The Conversation.

By Ellen Williams, Nottingham Trent University and Jessica Rendle, Murdoch University

More than 700 million people visit zoos and aquariums each year worldwide, so human visitors are usually a constant presence for the animals that live there. But the Covid-19 pandemic has forced these places to close to the public, plunging resident animals into an empty silence.

Instead, zoos have been opening virtually during the lockdown, allowing people to see behind the closed doors from the comfort of their living rooms. Chester Zoo in the UK hosted an online tour so popular that it “broke the internet when it went viral” according to one zookeeper, with hundreds of thousands of people worldwide flocking to the zoo’s Facebook page.

Zoo workers have described how animals are greeting the isolation during COVID-19 closures. One zoo in India reported that animals were “loving the quiet spell” – foxes were “frolicking around”, the hippopotamus was happily splashing in its pool and even the tigers were enjoying a dip. In other zoos, animals seem to be missing people. Twycross Zoo’s curator reported primates looking for zoo visitors, for instance.

A worker disinfects Giza Zoo in Egypt, April 12 2020. Image via EPA-EFE/ Khaled Elfiqi

Some zoo animals are forgetting all about their previous lives, with garden eels at one Japanese aquarium hiding when staff members approached their enclosure. Workers have asked the public to make video calls to their eels, to try and prevent them from seeing visitors as a threat when the aquarium reopens. Meanwhile, some animals are enjoying the freedom of daily zoo walks, like the penguins at the Shedd Aquarium in Chicago, which were let out to wander the empty halls and look into the other enclosures.

Eels have feelings too, ya know?

A Japanese aquarium asks people to video-call lonely eels who have forgotten humans. https://t.co/HyQiOccvDT pic.twitter.com/c1fZJgS1jB

— Natasha Fatah (@NatashaFatah) May 4, 2020

Is this reprieve from regular visitors healthy for zoo animals? And how will they respond to people suddenly flooding back once zoos reopen? Researchers and animal charities are worried that our pets will develop separation anxiety once their owners return to work. The opposite might happen among zoo animals. Will captive creatures be desperate for the public to return or have they adapted to a slower, quieter life?

When zoos reopen

As zoos that have closed for months reopen their doors, we have an opportunity to study how visitors influence the lives of zoo animals. While we can’t predict the future, previous research on how zoo animals have responded to changes in visitor schedules might give us some idea of what to expect.

During the night, zoo animals are used to relative peace and quiet. For many, beyond the odd security warden, there are no visitors. But before COVID-19, some zoos did open their doors outside of normal opening hours, for late-night tours and overnight camps.

During lockdown, zookeepers are the only human presence for many zoo animals. Image via EPA-EFE/ Roman Rios

Typically, we study animal behaviors to understand how they may be feeling and try to make judgements about their experiences. From that, we can say that zoo animals have tended to show mixed responses to evening events. A study at a zoo in Germany found that elephants sought comfort from others in their herd during an evening firework display, but they didn’t retreat into their indoor enclosures. Researchers at London Zoo noticed no changes in the behavior of lions during sunset safaris, on evenings when the zoo was open for visitors until 10pm, compared to their behavior during normal opening hours.

Across the board, changes in the usual routines of zoo animals affect different species in different ways. The quiet caused by vanished visitors might mean more animals performing attention-seeking behaviors to try and interact with visitors more than normal, as keepers have reported chimpanzees doing during lockdown, as they reach out towards workers who would usually feed them by hand. It may also cause them to be overly skittish to human visitors when they return, like the garden eels in Japan.

Amsterdam’s Artis Zoo has reopened for members only, instituting strict social distancing guidelines. Image via EPA-EFE/ Koen Van Weel/ The Conversation.

This is the longest time many zoo animals will have gone without the public, and zoo staff will have to help them transition back to normal life. Most zoos are planning phased reopenings of animal houses to prevent the sudden changes in noise disturbing the animals.

Some animals, especially those born during the COVID-19 lockdown, will never have experienced life in the public eye. Many up-close animal encounters will have to change, particularly as humans can transmit coronaviruses to great apes in captivity.

On your next visit, be cool, calm and collected. Keepers and other zoo staff will be on hand to guide you, helping enforce social distancing and supporting you on how best to behave around the animals. Your local zoo will need visitors more than ever when they reopen. But remember, zoo animals will be experiencing their own post lockdown fuzz, and, just like you, they may need time to adjust.

Ellen Williams, Lecturer in Animal Science, Nottingham Trent University and Jessica Rendle, Honorary Postdoctoral Associate in Conservation Medicine, Murdoch University

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

Bottom line: the COVID-19 pandemic has forced zoos and aquariums to close to the public. How are captive animals coping with the sudden emptiness?

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A Californian sea lion swims behind empty seats in its enclosure at a zoo in Berlin, April 4 2020. Image via EPA-EFE/ Clemens Bilan/ The Conversation.

By Ellen Williams, Nottingham Trent University and Jessica Rendle, Murdoch University

More than 700 million people visit zoos and aquariums each year worldwide, so human visitors are usually a constant presence for the animals that live there. But the Covid-19 pandemic has forced these places to close to the public, plunging resident animals into an empty silence.

Instead, zoos have been opening virtually during the lockdown, allowing people to see behind the closed doors from the comfort of their living rooms. Chester Zoo in the UK hosted an online tour so popular that it “broke the internet when it went viral” according to one zookeeper, with hundreds of thousands of people worldwide flocking to the zoo’s Facebook page.

Zoo workers have described how animals are greeting the isolation during COVID-19 closures. One zoo in India reported that animals were “loving the quiet spell” – foxes were “frolicking around”, the hippopotamus was happily splashing in its pool and even the tigers were enjoying a dip. In other zoos, animals seem to be missing people. Twycross Zoo’s curator reported primates looking for zoo visitors, for instance.

A worker disinfects Giza Zoo in Egypt, April 12 2020. Image via EPA-EFE/ Khaled Elfiqi

Some zoo animals are forgetting all about their previous lives, with garden eels at one Japanese aquarium hiding when staff members approached their enclosure. Workers have asked the public to make video calls to their eels, to try and prevent them from seeing visitors as a threat when the aquarium reopens. Meanwhile, some animals are enjoying the freedom of daily zoo walks, like the penguins at the Shedd Aquarium in Chicago, which were let out to wander the empty halls and look into the other enclosures.

Eels have feelings too, ya know?

A Japanese aquarium asks people to video-call lonely eels who have forgotten humans. https://t.co/HyQiOccvDT pic.twitter.com/c1fZJgS1jB

— Natasha Fatah (@NatashaFatah) May 4, 2020

Is this reprieve from regular visitors healthy for zoo animals? And how will they respond to people suddenly flooding back once zoos reopen? Researchers and animal charities are worried that our pets will develop separation anxiety once their owners return to work. The opposite might happen among zoo animals. Will captive creatures be desperate for the public to return or have they adapted to a slower, quieter life?

When zoos reopen

As zoos that have closed for months reopen their doors, we have an opportunity to study how visitors influence the lives of zoo animals. While we can’t predict the future, previous research on how zoo animals have responded to changes in visitor schedules might give us some idea of what to expect.

During the night, zoo animals are used to relative peace and quiet. For many, beyond the odd security warden, there are no visitors. But before COVID-19, some zoos did open their doors outside of normal opening hours, for late-night tours and overnight camps.

During lockdown, zookeepers are the only human presence for many zoo animals. Image via EPA-EFE/ Roman Rios

Typically, we study animal behaviors to understand how they may be feeling and try to make judgements about their experiences. From that, we can say that zoo animals have tended to show mixed responses to evening events. A study at a zoo in Germany found that elephants sought comfort from others in their herd during an evening firework display, but they didn’t retreat into their indoor enclosures. Researchers at London Zoo noticed no changes in the behavior of lions during sunset safaris, on evenings when the zoo was open for visitors until 10pm, compared to their behavior during normal opening hours.

Across the board, changes in the usual routines of zoo animals affect different species in different ways. The quiet caused by vanished visitors might mean more animals performing attention-seeking behaviors to try and interact with visitors more than normal, as keepers have reported chimpanzees doing during lockdown, as they reach out towards workers who would usually feed them by hand. It may also cause them to be overly skittish to human visitors when they return, like the garden eels in Japan.

Amsterdam’s Artis Zoo has reopened for members only, instituting strict social distancing guidelines. Image via EPA-EFE/ Koen Van Weel/ The Conversation.

This is the longest time many zoo animals will have gone without the public, and zoo staff will have to help them transition back to normal life. Most zoos are planning phased reopenings of animal houses to prevent the sudden changes in noise disturbing the animals.

Some animals, especially those born during the COVID-19 lockdown, will never have experienced life in the public eye. Many up-close animal encounters will have to change, particularly as humans can transmit coronaviruses to great apes in captivity.

On your next visit, be cool, calm and collected. Keepers and other zoo staff will be on hand to guide you, helping enforce social distancing and supporting you on how best to behave around the animals. Your local zoo will need visitors more than ever when they reopen. But remember, zoo animals will be experiencing their own post lockdown fuzz, and, just like you, they may need time to adjust.

Ellen Williams, Lecturer in Animal Science, Nottingham Trent University and Jessica Rendle, Honorary Postdoctoral Associate in Conservation Medicine, Murdoch University

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

Bottom line: the COVID-19 pandemic has forced zoos and aquariums to close to the public. How are captive animals coping with the sudden emptiness?

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Before 2020 ends, a great conjunction of Jupiter and Saturn

View at EarthSky Community Photos. | Closeup of Jupiter and Saturn, via Dr Ski. Saturn is now closely following Jupiter westward across the sky each night. Watch for the pair 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. Thank you, Dr Ski!

Astronomers use the word conjunction to describe meetings of planets and other objects on our sky’s dome. They use the term great conjunction to describe a meeting of two particular planets, very bright Jupiter and golden Saturn. The last great Jupiter-Saturn conjunction was May 28, 2000. The next one will be December 21, 2020. But don’t wait until December to start watching these worlds. They’re visible tonight and every night – near each other for the rest of 2020 – an appealing and mind-expanding sight! 

At the 2000 great conjunction, Jupiter and Saturn were near the sun in our sky and difficult to observe. We’re due for a more observable great conjunction, and we’ll get one. By December, Jupiter and Saturn will be visible in the west shortly after sunset.

That’s not where Jupiter and Saturn are now, however. In 2020, the pair appeared in the east before sunup in February. As the weeks passed, we watched them shift higher up in the predawn sky, where they were joined by Mars:

View at EarthSky Community Photos. | Jupiter, Saturn, Mars and the moon on May 17, 2020. In May, these planets have been stretched across the sky in a graceful line shortly before sunup. They follow a line across our sky because the planets of our solar system orbit the sun in a nearly flat plane. That plane (as defined by the Earth-sun plane) is called the ecliptic. Thus, whenever you’re looking for planets, be sure to look along the path traveled by the sun from east to west each day.

Now – as Earth has pursued its smaller, faster orbit around the sun – Jupiter and Saturn have come into view earlier at night. As June approaches, they’re rising so early that you can glimpse them ascending over your eastern horizon by about midnight. You’ll recognize them easily. Jupiter is brighter than any star. Saturn is not as bright as Jupiter, but it’s as bright as the brightest stars and shines with a distinctly golden color.

Unlike the twinkling stars, Jupiter and Saturn both shine steadily. Your next opportunity to identify them near the moon will be around June 7 and 8.

The moon, Jupiter and Saturn rising together in mid-to-late evening on June 7 and 8, 2020. As viewed from the Northern Hemisphere, they’ll rise into your southeastern sky. Read more. For a specific view from your particular location, try Stellarium-Web.

Saturn, the sixth planet outward from the sun, is the farthest and slowest-moving planet that we can easily see with the eye alone. Dazzling Jupiter, the fifth planet outward from the sun, is the second-slowest bright planet, after Saturn.

For that reason, Jupiter/Saturn conjunctions are the rarest of bright-planet conjunctions, by virtue of their slow motions in front of the constellations of the zodiac. Saturn takes nearly 30 years to go around the sun full circle whereas Jupiter takes nearly 12 years.

Thus, every 20 years, Jupiter catches up to Saturn as viewed from Earth.

Artist’s concept of Jupiter and Saturn in December of 2020, as viewed from a space-based perspective. Their conjunction will be December 21. See the moon in this drawing? It’ll be along our line of sight to the planets on December 16, 2020. Chart via Jay Ryan at ClassicalAstronomy.com.

From the years 2000 to 2100 inclusive, as viewed from our planet Earth, these Jupiter/Saturn conjunctions (in ecliptic longitude) happen on these dates:

May 28, 2000
December 21, 2020
October 31, 2040
April 7, 2060
March 15, 2080
September 18, 2100

These great Jupiter/Saturn conjunctions recur in periods of 20 years. Each year, Saturn completes about 12 degrees of its orbit around the sun, whereas Jupiter completes about 30 degrees. Therefore, in one year, Jupiter closes the gap between itself and Saturn by about 18 degrees (30 – 12 = 18 degrees). In a period of 20 years, then, Jupiter gains 360 degrees on Saturn (18 x 20 = 360 degrees), therefore lapping the ringed planet once every 20 years.

So start watching Jupiter and Saturn now! They’ll be at their best during June, July and August. During these months, Earth will pass between both Jupiter and Saturn and the sun, bringing these planets opposite the sun in our sky, to a position called opposition by astronomers. Jupiter will come to opposition on July 14. Saturn’s opposition will be July 20.

At opposition – when we on Earth are seeing these worlds opposite the sun – Jupiter and Saturn will rise in the east at sunset, appear highest in the sky at midnight, and set at sunrise. Afterwards, they’ll rise earlier and set earlier, day by day, appearing for fewer and fewer nighttime minutes throughout September, October, November and December.

The great conjunction of Jupiter and Saturn on December 21, 2020, will mark the end of the year of observing these worlds … and what a great year it is! Don’t miss Jupiter and Saturn in 2020.

View at EarthSky Community Photos. | Dr Ski added an arrow to show that Jupiter and Saturn are now moving in retrograde (westward) toward the famous Teapot pattern in the constellation Sagittarius. They won’t quite make it before resuming their normal, eastward motion in mid-September 2020. Thanks, Dr. Ski.

Bottom line: The upcoming great conjunction of Jupiter and Saturn will be December 21, 2020. This is a once-in-20-years event. The planets are visible now and will be at their best in June, July and August. Watch for them.

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View at EarthSky Community Photos. | Closeup of Jupiter and Saturn, via Dr Ski. Saturn is now closely following Jupiter westward across the sky each night. Watch for the pair 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. Thank you, Dr Ski!

Astronomers use the word conjunction to describe meetings of planets and other objects on our sky’s dome. They use the term great conjunction to describe a meeting of two particular planets, very bright Jupiter and golden Saturn. The last great Jupiter-Saturn conjunction was May 28, 2000. The next one will be December 21, 2020. But don’t wait until December to start watching these worlds. They’re visible tonight and every night – near each other for the rest of 2020 – an appealing and mind-expanding sight! 

At the 2000 great conjunction, Jupiter and Saturn were near the sun in our sky and difficult to observe. We’re due for a more observable great conjunction, and we’ll get one. By December, Jupiter and Saturn will be visible in the west shortly after sunset.

That’s not where Jupiter and Saturn are now, however. In 2020, the pair appeared in the east before sunup in February. As the weeks passed, we watched them shift higher up in the predawn sky, where they were joined by Mars:

View at EarthSky Community Photos. | Jupiter, Saturn, Mars and the moon on May 17, 2020. In May, these planets have been stretched across the sky in a graceful line shortly before sunup. They follow a line across our sky because the planets of our solar system orbit the sun in a nearly flat plane. That plane (as defined by the Earth-sun plane) is called the ecliptic. Thus, whenever you’re looking for planets, be sure to look along the path traveled by the sun from east to west each day.

Now – as Earth has pursued its smaller, faster orbit around the sun – Jupiter and Saturn have come into view earlier at night. As June approaches, they’re rising so early that you can glimpse them ascending over your eastern horizon by about midnight. You’ll recognize them easily. Jupiter is brighter than any star. Saturn is not as bright as Jupiter, but it’s as bright as the brightest stars and shines with a distinctly golden color.

Unlike the twinkling stars, Jupiter and Saturn both shine steadily. Your next opportunity to identify them near the moon will be around June 7 and 8.

The moon, Jupiter and Saturn rising together in mid-to-late evening on June 7 and 8, 2020. As viewed from the Northern Hemisphere, they’ll rise into your southeastern sky. Read more. For a specific view from your particular location, try Stellarium-Web.

Saturn, the sixth planet outward from the sun, is the farthest and slowest-moving planet that we can easily see with the eye alone. Dazzling Jupiter, the fifth planet outward from the sun, is the second-slowest bright planet, after Saturn.

For that reason, Jupiter/Saturn conjunctions are the rarest of bright-planet conjunctions, by virtue of their slow motions in front of the constellations of the zodiac. Saturn takes nearly 30 years to go around the sun full circle whereas Jupiter takes nearly 12 years.

Thus, every 20 years, Jupiter catches up to Saturn as viewed from Earth.

Artist’s concept of Jupiter and Saturn in December of 2020, as viewed from a space-based perspective. Their conjunction will be December 21. See the moon in this drawing? It’ll be along our line of sight to the planets on December 16, 2020. Chart via Jay Ryan at ClassicalAstronomy.com.

From the years 2000 to 2100 inclusive, as viewed from our planet Earth, these Jupiter/Saturn conjunctions (in ecliptic longitude) happen on these dates:

May 28, 2000
December 21, 2020
October 31, 2040
April 7, 2060
March 15, 2080
September 18, 2100

These great Jupiter/Saturn conjunctions recur in periods of 20 years. Each year, Saturn completes about 12 degrees of its orbit around the sun, whereas Jupiter completes about 30 degrees. Therefore, in one year, Jupiter closes the gap between itself and Saturn by about 18 degrees (30 – 12 = 18 degrees). In a period of 20 years, then, Jupiter gains 360 degrees on Saturn (18 x 20 = 360 degrees), therefore lapping the ringed planet once every 20 years.

So start watching Jupiter and Saturn now! They’ll be at their best during June, July and August. During these months, Earth will pass between both Jupiter and Saturn and the sun, bringing these planets opposite the sun in our sky, to a position called opposition by astronomers. Jupiter will come to opposition on July 14. Saturn’s opposition will be July 20.

At opposition – when we on Earth are seeing these worlds opposite the sun – Jupiter and Saturn will rise in the east at sunset, appear highest in the sky at midnight, and set at sunrise. Afterwards, they’ll rise earlier and set earlier, day by day, appearing for fewer and fewer nighttime minutes throughout September, October, November and December.

The great conjunction of Jupiter and Saturn on December 21, 2020, will mark the end of the year of observing these worlds … and what a great year it is! Don’t miss Jupiter and Saturn in 2020.

View at EarthSky Community Photos. | Dr Ski added an arrow to show that Jupiter and Saturn are now moving in retrograde (westward) toward the famous Teapot pattern in the constellation Sagittarius. They won’t quite make it before resuming their normal, eastward motion in mid-September 2020. Thanks, Dr. Ski.

Bottom line: The upcoming great conjunction of Jupiter and Saturn will be December 21, 2020. This is a once-in-20-years event. The planets are visible now and will be at their best in June, July and August. Watch for them.

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What are mammatus clouds? Stunning photos here

View larger at EarthSky Community Photos. | Adelina Bathorja in Tirane, Albania, captured these clouds on May 14, 2020. Adelina wrote: “For the first time ever I see mammatus clouds. Just, wow! It was a spectacular view of cellular and jellyfish patterns.”

Mammatus clouds are pouch-like protrusions hanging from the undersides of clouds, usually thunderstorm anvil clouds but other types of clouds as well. Composed primarily of ice, these cloud pouches can extend hundreds of miles in any direction, remaining visible in your sky for perhaps 10 or 15 minutes at a time.

People associate them with severe weather, and it’s true they can appear around, before or after a storm. Contrary to myth, they don’t continue extending downward to form tornados, but they are interesting in part because they’re formed by sinking air. Most clouds are formed by rising air. Mammatus clouds can appear ominous. But, in a way that’s so common in nature, their dangerous aspect goes hand in hand with a magnificent beauty.

View at EarthSky Community Photos. | Marlane Burns captured this image on May 15, 2020, near Robert Lee, Texas. She said: “Mammatus clouds preceding a northern thunderstorm that came out of nowhere! The wind blew the flies away and the rain settled the dust!”

View at EarthSky Community Photos. | Peter Lowenstein captured these spectacular mammatus clouds in Mutare, Zimbabwe, on March 23, 2020. He wrote: “I took an early morning walk up to the Murambi High Level Water Tanks in the hope of catching a glimpse of the very thin old moon rising. Instead there was a surprise appearance of mammatus clouds on the underside of a sunrise-illuminated band of altostratus cloud above.”

Stephanie Tilden Dorr in Wichita, Kansas, caught these clouds in June 2018. She wrote: “Mammatus clouds appearing exactly one hour after a hailstorm passed over. Twenty-five years in Kansas and I’ve only seen mammatus clouds this vivid one other time, years ago. So exciting!”

Mammatus clouds over New Jersey, via Phil Chillemi.

Mammatus clouds via Andrew Hill in Gloucestershire, U.K.

Crystal Kolb caught these mammatus clouds from Essex, Maryland – near Baltimore – after a bad storm.

Mammatus clouds at sunset from Andrew Ashton in Nampa, Idaho.

Josh Blash caught these mammatus clouds illuminated by lightning over Rye, New Hampshire.

From Lorrie Wy, who wrote in May 2014, “Bubbly clouds over central Alberta, approximately 9:20 p.m. Temp approximately plus 12. Winds cold and light from northwest. These clouds just rolled right over.”

Berit Roaldseth in Trondheim, Norway, saw these mammatus clouds after an April rain shower.

Mammatus clouds over Fayetteville, Arkansas, just before sunset. Image via Mike Price.

Mammatus clouds over Fort Worth, Texas, in May 2013 – the day a tornado struck near Oklahoma City. Photo via Sundog Art Photography.

Pam Rice Phillips caught the same mammatus clouds as in the image above, on May 20, 2013, the day a tornado struck Moore, Oklahoma. She was in Granbury, Texas, which is southwest of Fort Worth.

Mammatus clouds over Tynemouth, England, via Colin Cooper.

Mammatus clouds over Salt Lake City, Utah, from Shanna Dennis.

Mammatus clouds over Denver in 2012 via Larry Sessions.

Mammatus clouds over Half Dome in Yosemite National Park in June 2013 by Kristal Leonard.

Bottom line: A spectacular collection of photos of mammatus clouds.

from EarthSky https://ift.tt/33L8vWl

View larger at EarthSky Community Photos. | Adelina Bathorja in Tirane, Albania, captured these clouds on May 14, 2020. Adelina wrote: “For the first time ever I see mammatus clouds. Just, wow! It was a spectacular view of cellular and jellyfish patterns.”

Mammatus clouds are pouch-like protrusions hanging from the undersides of clouds, usually thunderstorm anvil clouds but other types of clouds as well. Composed primarily of ice, these cloud pouches can extend hundreds of miles in any direction, remaining visible in your sky for perhaps 10 or 15 minutes at a time.

People associate them with severe weather, and it’s true they can appear around, before or after a storm. Contrary to myth, they don’t continue extending downward to form tornados, but they are interesting in part because they’re formed by sinking air. Most clouds are formed by rising air. Mammatus clouds can appear ominous. But, in a way that’s so common in nature, their dangerous aspect goes hand in hand with a magnificent beauty.

View at EarthSky Community Photos. | Marlane Burns captured this image on May 15, 2020, near Robert Lee, Texas. She said: “Mammatus clouds preceding a northern thunderstorm that came out of nowhere! The wind blew the flies away and the rain settled the dust!”

View at EarthSky Community Photos. | Peter Lowenstein captured these spectacular mammatus clouds in Mutare, Zimbabwe, on March 23, 2020. He wrote: “I took an early morning walk up to the Murambi High Level Water Tanks in the hope of catching a glimpse of the very thin old moon rising. Instead there was a surprise appearance of mammatus clouds on the underside of a sunrise-illuminated band of altostratus cloud above.”

Stephanie Tilden Dorr in Wichita, Kansas, caught these clouds in June 2018. She wrote: “Mammatus clouds appearing exactly one hour after a hailstorm passed over. Twenty-five years in Kansas and I’ve only seen mammatus clouds this vivid one other time, years ago. So exciting!”

Mammatus clouds over New Jersey, via Phil Chillemi.

Mammatus clouds via Andrew Hill in Gloucestershire, U.K.

Crystal Kolb caught these mammatus clouds from Essex, Maryland – near Baltimore – after a bad storm.

Mammatus clouds at sunset from Andrew Ashton in Nampa, Idaho.

Josh Blash caught these mammatus clouds illuminated by lightning over Rye, New Hampshire.

From Lorrie Wy, who wrote in May 2014, “Bubbly clouds over central Alberta, approximately 9:20 p.m. Temp approximately plus 12. Winds cold and light from northwest. These clouds just rolled right over.”

Berit Roaldseth in Trondheim, Norway, saw these mammatus clouds after an April rain shower.

Mammatus clouds over Fayetteville, Arkansas, just before sunset. Image via Mike Price.

Mammatus clouds over Fort Worth, Texas, in May 2013 – the day a tornado struck near Oklahoma City. Photo via Sundog Art Photography.

Pam Rice Phillips caught the same mammatus clouds as in the image above, on May 20, 2013, the day a tornado struck Moore, Oklahoma. She was in Granbury, Texas, which is southwest of Fort Worth.

Mammatus clouds over Tynemouth, England, via Colin Cooper.

Mammatus clouds over Salt Lake City, Utah, from Shanna Dennis.

Mammatus clouds over Denver in 2012 via Larry Sessions.

Mammatus clouds over Half Dome in Yosemite National Park in June 2013 by Kristal Leonard.

Bottom line: A spectacular collection of photos of mammatus clouds.

from EarthSky https://ift.tt/33L8vWl

Markarian’s Chain of galaxies

View on Facebook. | Fred Espenak at Dark View Observatory, Portal, Arizona posted this image to EarthSky Facebook on May 19, 2020. Thank you, Fred!

Fred Espenak wrote:

At the heart of the Virgo Cluster of Galaxies lies a remarkable lineup of galaxies called Markarian’s Chain. This image captures the western end of the chain and features the two large, bright lenticular galaxies, M84 and M86. To the upper left is a pair of interacting galaxies known as The Eyes: NGC 4435 (top) and NGC 4438 (bottom). Dozens of smaller, fainter galaxies are also captured in this vista covering an area of the sky about twice the size of a full moon.

The Virgo Cluster contains over 2,000 galaxies, and has a noticeable gravitational pull on the galaxies of the Local Group of Galaxies surrounding our Milky Way Galaxy. The center of the Virgo Cluster is located about 70 million light-years away toward the constellation of Virgo. At least seven galaxies in the chain appear to move coherently.

This image was shot with an AstroPhysics 130 EDT refractor and a ZWO ASI183MC Pro cooled color CMOS camera. It is a stack of 34 individual 5 minute exposures making the combined exposure of 170 minutes.

Markarian’s Chain in the direction of the constellation Virgo, located within the Virgo Galaxy Cluster. Find an annotated version of this image here. Image via Hewholooks/ Wikimedia Commons.

Bottom line: An image of a lineup of galaxies called Markarian’s Chain, part of the Virgo Galaxy Cluster.

from EarthSky https://ift.tt/3d22ubm

View on Facebook. | Fred Espenak at Dark View Observatory, Portal, Arizona posted this image to EarthSky Facebook on May 19, 2020. Thank you, Fred!

Fred Espenak wrote:

At the heart of the Virgo Cluster of Galaxies lies a remarkable lineup of galaxies called Markarian’s Chain. This image captures the western end of the chain and features the two large, bright lenticular galaxies, M84 and M86. To the upper left is a pair of interacting galaxies known as The Eyes: NGC 4435 (top) and NGC 4438 (bottom). Dozens of smaller, fainter galaxies are also captured in this vista covering an area of the sky about twice the size of a full moon.

The Virgo Cluster contains over 2,000 galaxies, and has a noticeable gravitational pull on the galaxies of the Local Group of Galaxies surrounding our Milky Way Galaxy. The center of the Virgo Cluster is located about 70 million light-years away toward the constellation of Virgo. At least seven galaxies in the chain appear to move coherently.

This image was shot with an AstroPhysics 130 EDT refractor and a ZWO ASI183MC Pro cooled color CMOS camera. It is a stack of 34 individual 5 minute exposures making the combined exposure of 170 minutes.

Markarian’s Chain in the direction of the constellation Virgo, located within the Virgo Galaxy Cluster. Find an annotated version of this image here. Image via Hewholooks/ Wikimedia Commons.

Bottom line: An image of a lineup of galaxies called Markarian’s Chain, part of the Virgo Galaxy Cluster.

from EarthSky https://ift.tt/3d22ubm

Young moon, Venus, Mercury on May 23, 24 and 25

At evening dusk – May 23, 24 and 25, 2020 – find an unobstructed horizon in the direction of sunset, and watch for the young moon, plus the planets Mercury and Venus, to pop out in the deepening twilight. From many places worldwide, it’ll be tough to spot the whisker-thin lunar crescent beneath Venus and Mercury on May 23, because the moon will be out only briefly after sunset. It’ll be a lovely, fragile crescent that’ll follow the sun beneath the horizon before true darkness falls. Then on May 24 and 25, the moon will be easy. And, on all of these evenings, the planets near the moon will be breathtaking, with Venus piercing the very bright twilight and Mercury slightly higher up.

The Mercury-Venus conjunction took place on May 22 at around 7 UTC. That is when Mercury swept 0.9 degrees S. of Venus on our sky’s dome, and it’s why Mercury is now higher in the sky than Venus.

Click here to find out when the moon will set in your sky, remembering to check the moonrise/moonset box.

View larger at EarthSky Community Photos. Congratulations to Dustin Guy of Seattle, Washington, U.S., who caught last year’s May young moon after sunset May 5, 2019. Thank you, Dustin!

On May 23, you may well have an easier time spotting Venus than the young moon. After all, dazzling Venus ranks as the 3rd-brightest celestial object, after the sun and moon. But Venus looms higher up in the sky at sunset May 23, while the young moon is more submerged in the sunset glare. People with good vision (or binoculars) might see Venus as little as 10 to 20 minutes after sundown. Once you catch Venus, seek for a faint glimmer of lunar crescent in between Venus and the horizon at dusk May 23. While you’re at it, seek for Mercury above Venus with the eye alone or binoculars. Good luck!

Live in the United States or Canada? Find out when Mercury and Venus set in your sky via Old Farmer’s Almanac. Find out the sunrise/sunset times first and then scroll down to Rise and set times for the moon and planets.

Live elsewhere worldwide? Find out the setting times for Mercury and Venus via TimeandDate Planets.

View larger at EarthSky Community Photos. Last year, Mark Sansom of Melbourne, Australia, caught the young crescent in the west after sunset on May 6, 2019. Note that the crescent tilts in a different direction than in the above photo from the Northern Hemisphere. Thank you Mark!

Given clear skies, the young lunar crescent will be much easier to catch after the sun goes down on May 24 and 25. Day by day, a wider lunar crescent appears higher in the sky at sunset, and the moon stays out longer after dark. You’re also more likely to view the soft glow of earthshine on the dark – or nighttime – side of the moon. Earthshine is twice-reflected sunlight, with sunlight being reflected from Earth to the moon, and then from the moon back to Earth.

Ken Christison caught a very young moon, with its dark side all aglow in earthshine, on March 31, 2014, the day after a new moon.

Unlike the moon, which is climbing away from the setting sun, Venus is sinking closer to the sun day by day. These next several days will present Venus’ farewell appearance in the evening sky, before this world finally succumbs to the sun’s glare by the month’s end. In other words, May 2020 showcases the year’s final pairing of the crescent moon and Venus in the evening sky.

Mercury, on the other hand, is still edging away from the sun, to reach its greatest elongation (maximum angular separation from the sun) on June 4, 2020. So Mercury’s presence in the evening sky could last for another week or two. However, this world is dimming day by day, so we advise you not to dally. Catch Mercury while it’s still bright and beautiful, and you still have the young moon there to guide you. And don’t forget binoculars, if you have them.

We anticipate May 24 being the best date for observing the celestial threesome. Although this chart is especially made for mid-northern North American latitudes, the young moon will be close to these two planets on this date (May 24) everywhere worldwide. On May 24, from the world’s Eastern Hemisphere – Europe, Africa, Asia, Australia and New Zealand – you’ll actually see the moon closer to Mercury and Venus than we will in North America.

May 24 might present the optimal date for viewing this gorgeous celestial threesome as dusk gives way to darknnes. As seen from around the world, the young moon, Venus and Mercury will be fairly close together on the sky’s dome, enabling you to hop from the young moon to Mercury and Venus with minimal effort. (See the sky chart above.) Once again, we encourage you to bring along binoculars.

Bottom line: Shortly after sunset on May 23, 24 and 25, 2020, watch the great drama in your western twilight sky, as the young moon meets up with the two inferior planets, Mercury and Venus.

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

At evening dusk – May 23, 24 and 25, 2020 – find an unobstructed horizon in the direction of sunset, and watch for the young moon, plus the planets Mercury and Venus, to pop out in the deepening twilight. From many places worldwide, it’ll be tough to spot the whisker-thin lunar crescent beneath Venus and Mercury on May 23, because the moon will be out only briefly after sunset. It’ll be a lovely, fragile crescent that’ll follow the sun beneath the horizon before true darkness falls. Then on May 24 and 25, the moon will be easy. And, on all of these evenings, the planets near the moon will be breathtaking, with Venus piercing the very bright twilight and Mercury slightly higher up.

The Mercury-Venus conjunction took place on May 22 at around 7 UTC. That is when Mercury swept 0.9 degrees S. of Venus on our sky’s dome, and it’s why Mercury is now higher in the sky than Venus.

Click here to find out when the moon will set in your sky, remembering to check the moonrise/moonset box.

View larger at EarthSky Community Photos. Congratulations to Dustin Guy of Seattle, Washington, U.S., who caught last year’s May young moon after sunset May 5, 2019. Thank you, Dustin!

On May 23, you may well have an easier time spotting Venus than the young moon. After all, dazzling Venus ranks as the 3rd-brightest celestial object, after the sun and moon. But Venus looms higher up in the sky at sunset May 23, while the young moon is more submerged in the sunset glare. People with good vision (or binoculars) might see Venus as little as 10 to 20 minutes after sundown. Once you catch Venus, seek for a faint glimmer of lunar crescent in between Venus and the horizon at dusk May 23. While you’re at it, seek for Mercury above Venus with the eye alone or binoculars. Good luck!

Live in the United States or Canada? Find out when Mercury and Venus set in your sky via Old Farmer’s Almanac. Find out the sunrise/sunset times first and then scroll down to Rise and set times for the moon and planets.

Live elsewhere worldwide? Find out the setting times for Mercury and Venus via TimeandDate Planets.

View larger at EarthSky Community Photos. Last year, Mark Sansom of Melbourne, Australia, caught the young crescent in the west after sunset on May 6, 2019. Note that the crescent tilts in a different direction than in the above photo from the Northern Hemisphere. Thank you Mark!

Given clear skies, the young lunar crescent will be much easier to catch after the sun goes down on May 24 and 25. Day by day, a wider lunar crescent appears higher in the sky at sunset, and the moon stays out longer after dark. You’re also more likely to view the soft glow of earthshine on the dark – or nighttime – side of the moon. Earthshine is twice-reflected sunlight, with sunlight being reflected from Earth to the moon, and then from the moon back to Earth.

Ken Christison caught a very young moon, with its dark side all aglow in earthshine, on March 31, 2014, the day after a new moon.

Unlike the moon, which is climbing away from the setting sun, Venus is sinking closer to the sun day by day. These next several days will present Venus’ farewell appearance in the evening sky, before this world finally succumbs to the sun’s glare by the month’s end. In other words, May 2020 showcases the year’s final pairing of the crescent moon and Venus in the evening sky.

Mercury, on the other hand, is still edging away from the sun, to reach its greatest elongation (maximum angular separation from the sun) on June 4, 2020. So Mercury’s presence in the evening sky could last for another week or two. However, this world is dimming day by day, so we advise you not to dally. Catch Mercury while it’s still bright and beautiful, and you still have the young moon there to guide you. And don’t forget binoculars, if you have them.

We anticipate May 24 being the best date for observing the celestial threesome. Although this chart is especially made for mid-northern North American latitudes, the young moon will be close to these two planets on this date (May 24) everywhere worldwide. On May 24, from the world’s Eastern Hemisphere – Europe, Africa, Asia, Australia and New Zealand – you’ll actually see the moon closer to Mercury and Venus than we will in North America.

May 24 might present the optimal date for viewing this gorgeous celestial threesome as dusk gives way to darknnes. As seen from around the world, the young moon, Venus and Mercury will be fairly close together on the sky’s dome, enabling you to hop from the young moon to Mercury and Venus with minimal effort. (See the sky chart above.) Once again, we encourage you to bring along binoculars.

Bottom line: Shortly after sunset on May 23, 24 and 25, 2020, watch the great drama in your western twilight sky, as the young moon meets up with the two inferior planets, Mercury and Venus.

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

Is Mars still volcanically active? New study says maybe

Orbital view from Mars Express of Olympus Mons, the tallest volcano on Mars, stretching some 13.6 miles (22 km, 72,000 feet) above the red Martian plains. Olympus Mons is 2 1/2 times taller than Mount Everest! Image via ESA/ Justin Cowart.

Is Mars still volcanically active? At first glance, it wouldn’t seem to be, since no eruptions have ever been observed from any of the numerous volcanoes dotting its desert surface. Recent findings from NASA’s InSight lander have shown that there’s still at least some residual geologic activity underground, however, in the form of marsquakes. Now, a newly announced study of a Martian meteorite has provided the first evidence of what scientists call magma convection on Mars – a rising and falling of currents in molten material beneath Mars’ surface – that took place in the planet’s mantle a few hundred million years ago. Perhaps this slow roiling of magma beneath Mars’ crust still occurs today.

The new peer-reviewed findings were published in Meteoritics & Planetary Science on May 7, 2020.

The intriguing results – reported in ScienceAlert by Michelle Star on May 11, 2020 – come from a new study of the Tissint Martian meteorite. A Martian meteorite is a rock ejected from Mars, likely via an impact event, which traversed interplanetary space and ultimately landed on Earth. Found in Morocco on July 18, 2011, the Tissint meteorite originated from deep within Mars. Tissint has been the subject of much study already, but this time, the researchers found something surprising. The meteorite contained crystals of olivine, rock-forming minerals commonly found in Earth’s crust.

When those crystals were examined more closely, it was found that they could have only formed in changing temperatures within currents of magma convection.

Mars’ internal structure: core, mantle, crust and atmosphere. Image via IPGP/ David Ducros/ SEIS.

Diagram of a possible magma chamber on ancient Mars. The Tissint meteorite may have originated from a place like this, beneath Mars’ surface. Image via Mari et al./ Meteoritics & Planetary Science, 2020/ ScienceAlert.

The crystals are an estimated 674 to 582 million years old, fairly young geologically speaking, so the implication is that Mars was still volcanically active at that time. Planetary geologist Nicola Mari of the University of Glasgow told ScienceAlert:

There was no previous evidence of convection on Mars, but the question ‘Is Mars a still volcanically active planet?’ was previously investigated using different methods. However, this is the first study that proves activity in the Mars interior from a purely chemical point of view, on real Martian samples.

The olivine crystals would have formed inside a magma chamber deep underground. Olivine is common in Earth’s mantle, and even in meteorites. But the researchers noticed something odd about the olivine crystals in Tissint. They had irregularly-spaced bands composed of phosphorus. It’s a known process on Earth, called solute trapping, where, during rapid solidification, solute (the substance dissolved in a solution) may be incorporated into the solid phase at a concentration significantly different from that predicted by equilibrium thermodynamics.

The Tissint meteorite. Image via Alain Herzog/ EPFL.

Mari explained:

This occurs when the rate of crystal growth exceeds the rate at which phosphorus can diffuse through the melt, thus the phosphorus is obliged to enter the crystal structure instead of ‘swimming’ in the liquid magma. In the magma chamber that generated the lava that I studied, the convection was so vigorous that the olivines were moved from the bottom of the chamber (hotter) to the top (cooler) very rapidly, to be precise, this likely generated cooling rates of 15-30 degrees Celsius per hour [about 27-55 degrees Fahrenheit] for the olivines.

From the paper:

The Tissint martian meteorite is an unusual depleted olivine-phyric shergottite, reportedly sourced from a mantle-derived melt within a deep magma chamber. Here, we report major and trace element data for Tissint olivine and pyroxene, and use these data to provide new insights into the dynamics of the Tissint magma chamber. The presence of irregularly spaced oscillatory phosphorous (P)-rich bands in olivine, along with geochemical evidence indicative of a closed magmatic system, implies that the olivine grains were subject to solute trapping caused by vigorous crystal convection within the Tissint magma chamber. Calculated equilibration temperatures for the earliest crystallizing (antecrystic) olivine cores suggest a Tissint magma source temperature of 1680 degrees Celsius [3056 degrees Fahrenheit], and a local martian mantle temperature of 1560 degrees Celsius [2840 degrees F] during the Late Amazonian, the latter being consistent with the ambient mantle temperature of Archean Earth.

How do the researchers know the meteorite came originally from deep under Mars’ crust? The larger olivine crystals contained traces of nickel and cobalt. This, along with previous evidence, shows that the meteorite must have once been part of rock 25 to 50 miles (40 to 80 kilometers) beneath the surface.

False color x-ray images of 2 thin sections of the Tissint meteorite. Embedded olivine crystals are marked OI. Image via Mari et al./ Meteoritics & Planetary Science, 2020/ Wiley Online Library.

With all of this data, the researchers could estimate the temperatures in the Martian mantle at the time when the crystals first formed. They came up with 1,560 degrees Celsius (2840 degrees F) during the Martian Late Amazonian period. That’s a lot hotter than had been previously thought, almost as hot as 1,650 degrees Celsius (3002 F) during the Archean Eon on Earth, 4 to 2.5 billion years ago. This is recent enough, geologically, to suggest that Mars may still have active magma convection even today. Mari said:

I really think that Mars could be a still volcanically active world today, and these new results point toward this. We may not see a volcanic eruption on Mars for the next 5 million years, but this doesn’t mean that the planet is inactive. It could just mean that the timing between eruptions between Mars and Earth is different, and instead of seeing one or more eruptions per day (as on Earth) we could see a Martian eruption every n-millions of years.

So Mars may still be volcanically active today – as in recent geological time – but eruptions are spaced far apart, by a few million years, according to the researchers. It would be amazing to see a volcanic eruption on Mars, since the planet’s largest volcanoes are much larger than ones on Earth. Olympus Mons, the biggest of them all, is taller than Mount Everest!

Nicola Mari of the University of Glasgow, lead author of the new study. Image via Twitter.

In 2014, it was reported that the Tissint meteorite might contain traces of ancient microbial activity. According to Philippe Gillet, director of École Polytechnique de Lausanne (EPFL, Switzerland) Earth and Planetary Sciences Laboratory:

Insisting on certainty is unwise, particularly on such a sensitive topic. I’m completely open to the possibility that other studies might contradict our findings. However, our conclusions are such that they will rekindle the debate as to the possible existence of biological activity on Mars – at least in the past. So far, there is no other theory that we find more compelling.

While the jury is still out on the possible life traces, Tissint has shown, at the very least, that Mars was once much more active geologically than it is now.

Bottom line: A new study of an ancient Martian meteorite suggests that Mars was more volcanically active a few hundred million years ago than previously thought, and may even still be active today.

Source: Convective activity in a Martian magma chamber recorded by P-zoning in Tissint olivine

Via ScienceAlert

from EarthSky https://ift.tt/2yob1X5

Orbital view from Mars Express of Olympus Mons, the tallest volcano on Mars, stretching some 13.6 miles (22 km, 72,000 feet) above the red Martian plains. Olympus Mons is 2 1/2 times taller than Mount Everest! Image via ESA/ Justin Cowart.

Is Mars still volcanically active? At first glance, it wouldn’t seem to be, since no eruptions have ever been observed from any of the numerous volcanoes dotting its desert surface. Recent findings from NASA’s InSight lander have shown that there’s still at least some residual geologic activity underground, however, in the form of marsquakes. Now, a newly announced study of a Martian meteorite has provided the first evidence of what scientists call magma convection on Mars – a rising and falling of currents in molten material beneath Mars’ surface – that took place in the planet’s mantle a few hundred million years ago. Perhaps this slow roiling of magma beneath Mars’ crust still occurs today.

The new peer-reviewed findings were published in Meteoritics & Planetary Science on May 7, 2020.

The intriguing results – reported in ScienceAlert by Michelle Star on May 11, 2020 – come from a new study of the Tissint Martian meteorite. A Martian meteorite is a rock ejected from Mars, likely via an impact event, which traversed interplanetary space and ultimately landed on Earth. Found in Morocco on July 18, 2011, the Tissint meteorite originated from deep within Mars. Tissint has been the subject of much study already, but this time, the researchers found something surprising. The meteorite contained crystals of olivine, rock-forming minerals commonly found in Earth’s crust.

When those crystals were examined more closely, it was found that they could have only formed in changing temperatures within currents of magma convection.

Mars’ internal structure: core, mantle, crust and atmosphere. Image via IPGP/ David Ducros/ SEIS.

Diagram of a possible magma chamber on ancient Mars. The Tissint meteorite may have originated from a place like this, beneath Mars’ surface. Image via Mari et al./ Meteoritics & Planetary Science, 2020/ ScienceAlert.

The crystals are an estimated 674 to 582 million years old, fairly young geologically speaking, so the implication is that Mars was still volcanically active at that time. Planetary geologist Nicola Mari of the University of Glasgow told ScienceAlert:

There was no previous evidence of convection on Mars, but the question ‘Is Mars a still volcanically active planet?’ was previously investigated using different methods. However, this is the first study that proves activity in the Mars interior from a purely chemical point of view, on real Martian samples.

The olivine crystals would have formed inside a magma chamber deep underground. Olivine is common in Earth’s mantle, and even in meteorites. But the researchers noticed something odd about the olivine crystals in Tissint. They had irregularly-spaced bands composed of phosphorus. It’s a known process on Earth, called solute trapping, where, during rapid solidification, solute (the substance dissolved in a solution) may be incorporated into the solid phase at a concentration significantly different from that predicted by equilibrium thermodynamics.

The Tissint meteorite. Image via Alain Herzog/ EPFL.

Mari explained:

This occurs when the rate of crystal growth exceeds the rate at which phosphorus can diffuse through the melt, thus the phosphorus is obliged to enter the crystal structure instead of ‘swimming’ in the liquid magma. In the magma chamber that generated the lava that I studied, the convection was so vigorous that the olivines were moved from the bottom of the chamber (hotter) to the top (cooler) very rapidly, to be precise, this likely generated cooling rates of 15-30 degrees Celsius per hour [about 27-55 degrees Fahrenheit] for the olivines.

From the paper:

The Tissint martian meteorite is an unusual depleted olivine-phyric shergottite, reportedly sourced from a mantle-derived melt within a deep magma chamber. Here, we report major and trace element data for Tissint olivine and pyroxene, and use these data to provide new insights into the dynamics of the Tissint magma chamber. The presence of irregularly spaced oscillatory phosphorous (P)-rich bands in olivine, along with geochemical evidence indicative of a closed magmatic system, implies that the olivine grains were subject to solute trapping caused by vigorous crystal convection within the Tissint magma chamber. Calculated equilibration temperatures for the earliest crystallizing (antecrystic) olivine cores suggest a Tissint magma source temperature of 1680 degrees Celsius [3056 degrees Fahrenheit], and a local martian mantle temperature of 1560 degrees Celsius [2840 degrees F] during the Late Amazonian, the latter being consistent with the ambient mantle temperature of Archean Earth.

How do the researchers know the meteorite came originally from deep under Mars’ crust? The larger olivine crystals contained traces of nickel and cobalt. This, along with previous evidence, shows that the meteorite must have once been part of rock 25 to 50 miles (40 to 80 kilometers) beneath the surface.

False color x-ray images of 2 thin sections of the Tissint meteorite. Embedded olivine crystals are marked OI. Image via Mari et al./ Meteoritics & Planetary Science, 2020/ Wiley Online Library.

With all of this data, the researchers could estimate the temperatures in the Martian mantle at the time when the crystals first formed. They came up with 1,560 degrees Celsius (2840 degrees F) during the Martian Late Amazonian period. That’s a lot hotter than had been previously thought, almost as hot as 1,650 degrees Celsius (3002 F) during the Archean Eon on Earth, 4 to 2.5 billion years ago. This is recent enough, geologically, to suggest that Mars may still have active magma convection even today. Mari said:

I really think that Mars could be a still volcanically active world today, and these new results point toward this. We may not see a volcanic eruption on Mars for the next 5 million years, but this doesn’t mean that the planet is inactive. It could just mean that the timing between eruptions between Mars and Earth is different, and instead of seeing one or more eruptions per day (as on Earth) we could see a Martian eruption every n-millions of years.

So Mars may still be volcanically active today – as in recent geological time – but eruptions are spaced far apart, by a few million years, according to the researchers. It would be amazing to see a volcanic eruption on Mars, since the planet’s largest volcanoes are much larger than ones on Earth. Olympus Mons, the biggest of them all, is taller than Mount Everest!

Nicola Mari of the University of Glasgow, lead author of the new study. Image via Twitter.

In 2014, it was reported that the Tissint meteorite might contain traces of ancient microbial activity. According to Philippe Gillet, director of École Polytechnique de Lausanne (EPFL, Switzerland) Earth and Planetary Sciences Laboratory:

Insisting on certainty is unwise, particularly on such a sensitive topic. I’m completely open to the possibility that other studies might contradict our findings. However, our conclusions are such that they will rekindle the debate as to the possible existence of biological activity on Mars – at least in the past. So far, there is no other theory that we find more compelling.

While the jury is still out on the possible life traces, Tissint has shown, at the very least, that Mars was once much more active geologically than it is now.

Bottom line: A new study of an ancient Martian meteorite suggests that Mars was more volcanically active a few hundred million years ago than previously thought, and may even still be active today.

Source: Convective activity in a Martian magma chamber recorded by P-zoning in Tissint olivine

Via ScienceAlert

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