1st quarter moon is April 30

View at EarthSky Community Photos. | Composite image of a moon nearly at 1st quarter with some of the features you can see on the moon at this phase – captured April 30, 2020 – by our friend Dr Ski in the Philippines. He wrote: ” … 10 hours before 1st quarter and the Lunar V and Lunar X are well defined … ” More about Lunar V and X below. Thank you Dr Ski!

A first quarter moon rises around noon and sets around midnight. You’ll likely spot it in late afternoon or early evening, when it’s at its highest in the sky. At this moon phase, the moon is showing us precisely half of its lighted half. Or you might say that – at first quarter moon – we’re seeing half the moon’s day side.

We call this moon a quarter and not a half because it is one quarter of the way around in its orbit of Earth, as measured from one new moon to the next. Also, although a first quarter moon appears half-lit to us, the illuminated portion we see of a first quarter moon truly is just a quarter. We’re now seeing half the moon’s day side, that is. Another lighted quarter of the moon shines just as brightly in the direction opposite Earth!

And what about the term half moon? That’s a beloved term, but not an official one.

Lunar X and Lunar V appear when the moon is near its 1st quarter phase. They aren’t really Xs and Vs on the moon. They’re just high areas, catching sunlight, creating an example of pareidolia on the moon. Aqilla Othman in Port Dickson, Negeri Sembilan, Malaysia, caught them both in May of 2017. Notice that he caught Lunar X and Lunar V.

Here’s a closer look at Lunar X and Lunar V. Photo by Izaty Liyana in Port Dickson, Negeri Sembilan, Malaysia. What is Lunar X?

Tom Wildoner wrote: “One of my favorite areas to photograph on the moon near the 1st quarter! I captured this view of the sun lighting up the mountain range called Montes Apenninus. The moon was casting a nice shadow on the back side of the mountains. This mountain range is about 370 miles (600 km) long with some of the peaks rising as high as 3.1 miles (5 km).”

Bottom line: The next 1st quarter moon will come on April 30, 2020, at 20:39 UTC. As viewed from anywhere on Earth, a 1st quarter moon is at its highest in the sky at sunset, looking like half a pie.

Check out EarthSky’s guide to the bright planets.

Help EarthSky keep going! Please donate.

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

View at EarthSky Community Photos. | Composite image of a moon nearly at 1st quarter with some of the features you can see on the moon at this phase – captured April 30, 2020 – by our friend Dr Ski in the Philippines. He wrote: ” … 10 hours before 1st quarter and the Lunar V and Lunar X are well defined … ” More about Lunar V and X below. Thank you Dr Ski!

A first quarter moon rises around noon and sets around midnight. You’ll likely spot it in late afternoon or early evening, when it’s at its highest in the sky. At this moon phase, the moon is showing us precisely half of its lighted half. Or you might say that – at first quarter moon – we’re seeing half the moon’s day side.

We call this moon a quarter and not a half because it is one quarter of the way around in its orbit of Earth, as measured from one new moon to the next. Also, although a first quarter moon appears half-lit to us, the illuminated portion we see of a first quarter moon truly is just a quarter. We’re now seeing half the moon’s day side, that is. Another lighted quarter of the moon shines just as brightly in the direction opposite Earth!

And what about the term half moon? That’s a beloved term, but not an official one.

Lunar X and Lunar V appear when the moon is near its 1st quarter phase. They aren’t really Xs and Vs on the moon. They’re just high areas, catching sunlight, creating an example of pareidolia on the moon. Aqilla Othman in Port Dickson, Negeri Sembilan, Malaysia, caught them both in May of 2017. Notice that he caught Lunar X and Lunar V.

Here’s a closer look at Lunar X and Lunar V. Photo by Izaty Liyana in Port Dickson, Negeri Sembilan, Malaysia. What is Lunar X?

Tom Wildoner wrote: “One of my favorite areas to photograph on the moon near the 1st quarter! I captured this view of the sun lighting up the mountain range called Montes Apenninus. The moon was casting a nice shadow on the back side of the mountains. This mountain range is about 370 miles (600 km) long with some of the peaks rising as high as 3.1 miles (5 km).”

Bottom line: The next 1st quarter moon will come on April 30, 2020, at 20:39 UTC. As viewed from anywhere on Earth, a 1st quarter moon is at its highest in the sky at sunset, looking like half a pie.

Check out EarthSky’s guide to the bright planets.

Help EarthSky keep going! Please donate.

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

May 2020 guide to the bright planets

Click the name of a planet to learn more about its visibility in May 2020. Evening planets: Venus and Mercury. Morning planets: Jupiter, Saturn and Mars.

Try Stellarium for a precise view of the planets from your location.

Want precise planet rise and set times? Click here for recommended almanacs

You can catch all 5 bright planets in May 2020. Use the waning moon to catch the morning planets – Jupiter, Saturn and Mars – from May 11 to 14, 2020. Read more.

During the most of May 2020, the dazzling planet Venus appears between the bright stars Capella and Betelgeuse. Read more.

We expect Mercury, the innermost planet, to become visible by mid-May 2020, if not before. Conveniently, the dazzling planet Venus is there to help guide you to Mercury’s place near the horizon. Read more.

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

The young waxing crescent moon swings by the two inferior planets – Venus and Mercury – on May 23 and 24, 2020. Read more.

Venus – the brightest planet – blazes mightily in the western sky after sunset. Given clear skies, it’ll be hard to miss Venus, the third-brightest celestial body to light up the heavens, after the sun and moon, respectively. Some sharp-sighted people can even see Venus in a daytime sky.

May 2020 presents the last month for Venus’ reign in the evening sky. Day by day, Venus sinks closer to the glare of sunset, to swing behind the sun on June 3, 2020. After that, Venus transitions over to the morning sky. Look for Venus to reappear in the eastern dawn by around mid-June.

At mid-northern latitudes, Venus sets about 3 1/3 hours after the sun in early May, tapering to about 1/2 hour by the month’s end.

At and near the equator, Venus sets about 2 1/2 hours after the sun in early May, tapering to a bit over 1/3 hour near the month’s end.

At temperate latitudes in the Southern Hemisphere, Venus sets about 1 3/4 hours after the sun in early May, tapering to about 1/3 hour by the month’s end.

Around the world, Venus, in its faster orbit around the sun, comes closer to Earth day by day. Therefore, Venus’ thinning (yet elongating) phase becomes easier and easier to view through the telescope. Venus starts out the month about 25 percent illuminated in sunshine, and finishes the month about 0.5 percent illuminated. Venus’ angular diameter increases by 150% throughout the month, whereas its disk size more than doubles.

This month showcases Venus at its best in the evening sky as viewed through the telescope. Keep in mind, though, that you get a crisper view of Venus’ phase in a twilight or daytime sky than after dark. That’s because Venus’ glare is so overwhelming at nighttime. During the second half of the month, it might even be possible to view the crescent Venus through binoculars.

This month, as Venus sinks closer to the sunset day by day, Mercury will be climbing out of the sunset glare and in the direction of Venus. These two worlds will meet up for a conjunction on May 21, 2020. Once you see Venus, aim binoculars at Venus to spot nearby Mercury and Venus in the same binocular field together. As the evening twilight deepens, chances are that you’ll be able to spot Mercury next to Venus with the eye alone.

Read more: Mercury and Venus pair up at dusk May 21 and 22

Look for the moon in the vicinity of Venus (and Mercury) for several days, starting on or near May 23, 2020.

Mercury enters the evening sky on May 4. However, this world probably won’t be far enough from the sun’s glare to be visible until a week or so later. Fortunately, Venus and Mercury will stage a conjunction on May 21, with Mercury passing one degree to the south of Venus. After their conjunction, Mercury will climb upward day by day while Venus will descend downward. As long as you can catch Venus after sunset, seek for Mercury above Venus with the eye alone or binoculars.

At mid-northern latitudes, Mercury sets about one hour after the sun at mid-month, increasing to nearby 2 hours by early June.

At or near the equator, Mercury sets a bit less than one hour after the sun at mid-month, increasing to 1 2/3 hours by early June.

At temperate latitudes in the Southern Hemisphere, Mercury sets about 1/2 hour after sunset at mid-month, increasing to about 1 1/2 hours by early June.

Look for the young waxing crescent moon to shine in the vicinity of Mercury (and Venus) on May 23 and 24.

Mars is the last of the three bright morning planets to rise in May 2020. Jupiter rises first, closely followed by Saturn, and then a few hours later by Mars. Whereas Jupiter and Saturn almost rise in tandem, Mars is off by itself.

At mid-northern latitudes, Mars rises about two hours after midnight in early May, and about an hour after midnight by the month’s end. By midnight, we mean midway between sunset and sunrise. At temperate latitudes in the Southern Hemisphere, Mars comes around the midnight hour throughout the month.

Let the waning crescent moon help guide your eye to Mars for several mornings, centered around May 15.

Mars was in conjunction with the sun – or almost behind the sun as seen from Earth – on September 2, 2019. It was far across the solar system from us at the time. But Earth is now moving toward the red planet, reducing the distance between us and Mars each month. Even so, it’ll be a number of months before we catch Mars, the swiftest-moving superior planet. And so it is, always, for Mars, which alternates years appearing bright in our sky, or faint. 2019 was a dull year, but 2020 will be an exciting one, for Mars!

The excitement will build slowly, though. In May 2020 … you’ll still find Mars respectably bright before dawn. We’ll be rushing along in our smaller, faster orbit, trying to catch up with Mars. As northern summer 2020 approaches, Mars will begin to change. It’ll brighten more dramatically as, finally, Earth begins to close in on Mars. The red planet will appear brightest in our sky and fiery red – around the time of its opposition – when Earth passes between Mars and the sun on October 13, 2020.

View at EarthSky Community Photos. | From Paul Armstrong, who took this photo of Mars, Saturn and Jupiter on the morning of April 15, 2020, from Exmoor, UK. Jupiter is at the upper right, Mars at center left, with Saturn in between. In May 2020, Jupiter and Saturn will be closer together, whereas Mars will be farther away from Jupiter and Saturn. Thanks, Paul!

Jupiter and Saturn are closely joined at the hip on the sky’s dome, remaining rather close together in the morning sky all month long. Look first for brilliant Jupiter and you’ll find Saturn a short hop to the east of Jupiter. Remember, east is in the direction of sunrise. 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.

At mid-northern latitudes, Jupiter and nearby Saturn rise about one hour after midnight in early May, and, by the month’s end, rise about one hour before midnight. By midnight, we mean midway between sunset and sunrise. At temperate latitudes in the Southern Hemisphere, Jupiter and Saturn rise at late evening in early May, and around mid-evening by the month’s end.

Mars, which is roughly the same brightness as Saturn, more or less aligns with Jupiter and Saturn in the predawn/dawn sky. However, standoffish Mars is long jump to the east of Jupiter and Saturn, with Saturn shining in between Jupiter and Mars.

Watch for the moon in the vicinity of Jupiter and Saturn for several days, centered on or near May 12 and 13.

What do we mean by bright planet? By bright planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five bright planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets actually do appear bright in our sky. They are typically as bright as – or brighter than – the brightest stars. Plus, these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. You can spot them, and come to know them as faithful friends, if you try.

Skywatcher, by Predrag Agatonovic.

Bottom line: May 2020 presents all 5 bright solar system planets. Dazzling Venus is your ticket to finding Mercury in the evening sky, whereas brilliant Jupiter acts as your tour guide to Saturn and Mars in the morning sky. Quite by coincidence, the inferior planets – Mercury and Venus – reign in the evening sky while the superior planets – Mars, Jupiter and Saturn – predominate over the morning sky.

Don’t miss anything. Subscribe to EarthSky News by email

Visit EarthSky’s Best Places to Stargaze, and recommend a place we can all enjoy.

Help EarthSky keep going! Donate now.

Post your planet photos at EarthSky Community Photos

from EarthSky https://ift.tt/1YD00CF

Click the name of a planet to learn more about its visibility in May 2020. Evening planets: Venus and Mercury. Morning planets: Jupiter, Saturn and Mars.

Try Stellarium for a precise view of the planets from your location.

Want precise planet rise and set times? Click here for recommended almanacs

You can catch all 5 bright planets in May 2020. Use the waning moon to catch the morning planets – Jupiter, Saturn and Mars – from May 11 to 14, 2020. Read more.

During the most of May 2020, the dazzling planet Venus appears between the bright stars Capella and Betelgeuse. Read more.

We expect Mercury, the innermost planet, to become visible by mid-May 2020, if not before. Conveniently, the dazzling planet Venus is there to help guide you to Mercury’s place near the horizon. Read more.

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

The young waxing crescent moon swings by the two inferior planets – Venus and Mercury – on May 23 and 24, 2020. Read more.

Venus – the brightest planet – blazes mightily in the western sky after sunset. Given clear skies, it’ll be hard to miss Venus, the third-brightest celestial body to light up the heavens, after the sun and moon, respectively. Some sharp-sighted people can even see Venus in a daytime sky.

May 2020 presents the last month for Venus’ reign in the evening sky. Day by day, Venus sinks closer to the glare of sunset, to swing behind the sun on June 3, 2020. After that, Venus transitions over to the morning sky. Look for Venus to reappear in the eastern dawn by around mid-June.

At mid-northern latitudes, Venus sets about 3 1/3 hours after the sun in early May, tapering to about 1/2 hour by the month’s end.

At and near the equator, Venus sets about 2 1/2 hours after the sun in early May, tapering to a bit over 1/3 hour near the month’s end.

At temperate latitudes in the Southern Hemisphere, Venus sets about 1 3/4 hours after the sun in early May, tapering to about 1/3 hour by the month’s end.

Around the world, Venus, in its faster orbit around the sun, comes closer to Earth day by day. Therefore, Venus’ thinning (yet elongating) phase becomes easier and easier to view through the telescope. Venus starts out the month about 25 percent illuminated in sunshine, and finishes the month about 0.5 percent illuminated. Venus’ angular diameter increases by 150% throughout the month, whereas its disk size more than doubles.

This month showcases Venus at its best in the evening sky as viewed through the telescope. Keep in mind, though, that you get a crisper view of Venus’ phase in a twilight or daytime sky than after dark. That’s because Venus’ glare is so overwhelming at nighttime. During the second half of the month, it might even be possible to view the crescent Venus through binoculars.

This month, as Venus sinks closer to the sunset day by day, Mercury will be climbing out of the sunset glare and in the direction of Venus. These two worlds will meet up for a conjunction on May 21, 2020. Once you see Venus, aim binoculars at Venus to spot nearby Mercury and Venus in the same binocular field together. As the evening twilight deepens, chances are that you’ll be able to spot Mercury next to Venus with the eye alone.

Read more: Mercury and Venus pair up at dusk May 21 and 22

Look for the moon in the vicinity of Venus (and Mercury) for several days, starting on or near May 23, 2020.

Mercury enters the evening sky on May 4. However, this world probably won’t be far enough from the sun’s glare to be visible until a week or so later. Fortunately, Venus and Mercury will stage a conjunction on May 21, with Mercury passing one degree to the south of Venus. After their conjunction, Mercury will climb upward day by day while Venus will descend downward. As long as you can catch Venus after sunset, seek for Mercury above Venus with the eye alone or binoculars.

At mid-northern latitudes, Mercury sets about one hour after the sun at mid-month, increasing to nearby 2 hours by early June.

At or near the equator, Mercury sets a bit less than one hour after the sun at mid-month, increasing to 1 2/3 hours by early June.

At temperate latitudes in the Southern Hemisphere, Mercury sets about 1/2 hour after sunset at mid-month, increasing to about 1 1/2 hours by early June.

Look for the young waxing crescent moon to shine in the vicinity of Mercury (and Venus) on May 23 and 24.

Mars is the last of the three bright morning planets to rise in May 2020. Jupiter rises first, closely followed by Saturn, and then a few hours later by Mars. Whereas Jupiter and Saturn almost rise in tandem, Mars is off by itself.

At mid-northern latitudes, Mars rises about two hours after midnight in early May, and about an hour after midnight by the month’s end. By midnight, we mean midway between sunset and sunrise. At temperate latitudes in the Southern Hemisphere, Mars comes around the midnight hour throughout the month.

Let the waning crescent moon help guide your eye to Mars for several mornings, centered around May 15.

Mars was in conjunction with the sun – or almost behind the sun as seen from Earth – on September 2, 2019. It was far across the solar system from us at the time. But Earth is now moving toward the red planet, reducing the distance between us and Mars each month. Even so, it’ll be a number of months before we catch Mars, the swiftest-moving superior planet. And so it is, always, for Mars, which alternates years appearing bright in our sky, or faint. 2019 was a dull year, but 2020 will be an exciting one, for Mars!

The excitement will build slowly, though. In May 2020 … you’ll still find Mars respectably bright before dawn. We’ll be rushing along in our smaller, faster orbit, trying to catch up with Mars. As northern summer 2020 approaches, Mars will begin to change. It’ll brighten more dramatically as, finally, Earth begins to close in on Mars. The red planet will appear brightest in our sky and fiery red – around the time of its opposition – when Earth passes between Mars and the sun on October 13, 2020.

View at EarthSky Community Photos. | From Paul Armstrong, who took this photo of Mars, Saturn and Jupiter on the morning of April 15, 2020, from Exmoor, UK. Jupiter is at the upper right, Mars at center left, with Saturn in between. In May 2020, Jupiter and Saturn will be closer together, whereas Mars will be farther away from Jupiter and Saturn. Thanks, Paul!

Jupiter and Saturn are closely joined at the hip on the sky’s dome, remaining rather close together in the morning sky all month long. Look first for brilliant Jupiter and you’ll find Saturn a short hop to the east of Jupiter. Remember, east is in the direction of sunrise. 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.

At mid-northern latitudes, Jupiter and nearby Saturn rise about one hour after midnight in early May, and, by the month’s end, rise about one hour before midnight. By midnight, we mean midway between sunset and sunrise. At temperate latitudes in the Southern Hemisphere, Jupiter and Saturn rise at late evening in early May, and around mid-evening by the month’s end.

Mars, which is roughly the same brightness as Saturn, more or less aligns with Jupiter and Saturn in the predawn/dawn sky. However, standoffish Mars is long jump to the east of Jupiter and Saturn, with Saturn shining in between Jupiter and Mars.

Watch for the moon in the vicinity of Jupiter and Saturn for several days, centered on or near May 12 and 13.

What do we mean by bright planet? By bright planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five bright planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets actually do appear bright in our sky. They are typically as bright as – or brighter than – the brightest stars. Plus, these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. You can spot them, and come to know them as faithful friends, if you try.

Skywatcher, by Predrag Agatonovic.

Bottom line: May 2020 presents all 5 bright solar system planets. Dazzling Venus is your ticket to finding Mercury in the evening sky, whereas brilliant Jupiter acts as your tour guide to Saturn and Mars in the morning sky. Quite by coincidence, the inferior planets – Mercury and Venus – reign in the evening sky while the superior planets – Mars, Jupiter and Saturn – predominate over the morning sky.

Don’t miss anything. Subscribe to EarthSky News by email

Visit EarthSky’s Best Places to Stargaze, and recommend a place we can all enjoy.

Help EarthSky keep going! Donate now.

Post your planet photos at EarthSky Community Photos

from EarthSky https://ift.tt/1YD00CF

Will Dragonfly find dust devils on Titan?

Titan has vast fields of sand dunes, similar to those on Earth and Mars. New research suggests that dust devils might play a role in their formation. Image via NASA/ JPL-Caltech/ Sci-News.com.

Dust devils – short-lived whirlwinds filled with dust grains – are common on Earth, and even on Mars, where various rovers and orbiters have observed them many times. Now there’s another world in the solar system where dust devils might roam, according to a new study from researchers at Boise State University in Idaho. It’s Saturn’s large moon, Titan! And NASA’s planned Dragonfly mission – a drone-like flying robot able to perform vertical-takeoffs and landings – will be able to find them.

The intriguing possibility of dust devils on Titan was the subject of a recent post in AGU Blogosphere by Liza Lester of the American Geophysical Union. The new peer-reviewed paper detailing the dust devil research was published in Geophysical Research Letters on March 3, 2020.

From the paper:

Saturn’s moon Titan may host active dust devils, small dust-laden plumes, which could significantly contribute to transport of dust in that moon’s atmosphere. Although the exact nature of dust on Titan is unclear, previous observations confirm that there is actively blowing dust on that world. If dust devils are active on Titan’s surface, NASA’s upcoming Dragonfly mission is likely to encounter them, but dust devils on Titan are unlikely to pose a hazard to the mission.

The arrival of NASA’s Dragonfly mission on Titan in 2034 presents the prospect of probing extraterrestrial vortices in a similar way to these field studies, although encounters will probably occur primarily while Dragonfly is on the ground. However, Titan’s relevant meteorological conditions suggest that vortex encounters, if in-flight, may occur a few times during Dragonfly’s daily flight. The low wind speeds expected for dust devils on Titan mean they will pose little to no hazard to the mission. However, Dragonfly will spend most of its time on the ground, including during Titan’s midday when vortices are most likely to be active, and so encounters will probably occur on the ground every few Earth hours instead. In this case, they will likely resemble encounters on Mars by landed spacecraft. Even then, though, the imagery and meteorological data collected by Dragonfly during encounters may break new ground in aeolian studies by showing how they operate in a new aerodynamic environment.

Titan with Mimas in the foreground, as seen by Cassini on June 16, 2011. Like Earth and Mars, a new study suggests that Titan has dust devils. Image via NASA/ JPL-Caltech/ Space Science Institute/ Sci-News.com.

It’s been known for some time now, thanks to the Cassini mission to Saturn and its moons, that Titan has vast expanses of sand dunes (composed of organic hydrocarbon particles, unlike Earth and Mars). Winds on Titan are typically rather weak, but the dune particles do get transported around, and dust devils might be an ideal mechanism for that to happen. As Brian Jackson, a planetary scientist at BSU, said in a statement:

Winds at the surface of Titan are usually very weak. Unless there is a big storm rolling through, there’s probably not that much wind, and so dust devils may be one of the main dust transport mechanisms on Titan, if they exist.

So far, dust devils haven’t actually been seen yet on Titan, but meteorological models, based on data from the Huygens probe which landed on Titan in 2005, suggest they should be possible. Jackson said:

When we plug the numbers in for how much dust the dust devil ought to lift based on the wind speeds we see, they seem to be able to lift more dust than we would expect. There may be some other mechanism which is helping them pull this dust, or the equations are just wrong.

Artist’s concept of Dragonfly soaring over Titan’s surface. Image via NASA/ JHUAPL/ NPR.

On Earth, dust devils are very common (I remember even being briefly caught in a small one when I was a kid). In order to get more insight into how earthly dust devils form, Jackson and his colleagues studied ones in southeastern Oregon’s Alvord Desert, using small airborne drones carrying meteorological instruments. Those findings can be compared with observations of dust devils on Mars. According to Jackson:

We can watch dust devils skitter across the surface of Mars and see what their internal structure is like, but that doesn’t tell us how much dust they are lifting. Mars’ atmosphere is really, really dusty and dust plays an important role in the climate. Dust devils are probably, if not the dominant mechanism, one of the most important mechanisms for lofting the dust.

Mars’ atmosphere is extremely thin, yet dust devils can still reach a height of 5 miles (8 km). This is especially true during the Martian summer. Mars is very dusty – dust is literally everywhere – and that dust can be carried all over the planet despite the thinness of the atmosphere. The planet even experiences periodic global dust storms.

So how does this apply to Titan?

Titan has a thick atmosphere. It’s even thicker than Earth’s. But it only has one-seventh the gravity of Earth. Because of this, winds on Titan tend to be a lot gentler than those on Earth or even Mars. Jackson said:

It’s just this enormous, puffy atmosphere. When you’ve got that much air it’s hard to get it churning. So you just don’t usually get big winds on the surface of Titan so far as we know.

Since, as far as we know, Titan doesn’t have raging wind storms, smaller dust devils might be a good way to transport the hydrocarbon particles and create the massive dune fields. In this way, Titan would be similar to Mars, even though there are such large differences in atmospheric density and composition, wind speed and sand composition between the two worlds.

It will be a while before we can learn more about dust devils on Titan, and whether they even do actually exist. Dragonfly doesn’t launch until 2026, and won’t arrive at Titan until 2034. The Cassini mission, which ended in 2017, was the most recent to visit Saturn and its moons, with no other missions upcoming until Dragonfly.

Brian Jackson at Boise State University (BSU), the lead author of the new study. Image via BSU.

If Dragonfly does find dust devils, it will be fascinating to compare them to the ones on Earth and Mars. This is especially true since Titan is remarkably similar to Earth in some ways, with its rain, rivers, lakes and seas, albeit composed of liquid methane and ethane instead of water. Combined with the sand dunes, you could almost mistake the landscape seen in images sent back as being on Earth, if it weren’t for the smoggy-looking orange-ish sky. Dust devils would add to that already somewhat eerie – yet oddly reminiscent – alien landscape.

Bottom line: Titan may have dust devils like Earth and Mars, a new study says.

Source: Dust Devils on Titan

Via Phys.org

from EarthSky https://ift.tt/3bMkA0u

Titan has vast fields of sand dunes, similar to those on Earth and Mars. New research suggests that dust devils might play a role in their formation. Image via NASA/ JPL-Caltech/ Sci-News.com.

Dust devils – short-lived whirlwinds filled with dust grains – are common on Earth, and even on Mars, where various rovers and orbiters have observed them many times. Now there’s another world in the solar system where dust devils might roam, according to a new study from researchers at Boise State University in Idaho. It’s Saturn’s large moon, Titan! And NASA’s planned Dragonfly mission – a drone-like flying robot able to perform vertical-takeoffs and landings – will be able to find them.

The intriguing possibility of dust devils on Titan was the subject of a recent post in AGU Blogosphere by Liza Lester of the American Geophysical Union. The new peer-reviewed paper detailing the dust devil research was published in Geophysical Research Letters on March 3, 2020.

From the paper:

Saturn’s moon Titan may host active dust devils, small dust-laden plumes, which could significantly contribute to transport of dust in that moon’s atmosphere. Although the exact nature of dust on Titan is unclear, previous observations confirm that there is actively blowing dust on that world. If dust devils are active on Titan’s surface, NASA’s upcoming Dragonfly mission is likely to encounter them, but dust devils on Titan are unlikely to pose a hazard to the mission.

The arrival of NASA’s Dragonfly mission on Titan in 2034 presents the prospect of probing extraterrestrial vortices in a similar way to these field studies, although encounters will probably occur primarily while Dragonfly is on the ground. However, Titan’s relevant meteorological conditions suggest that vortex encounters, if in-flight, may occur a few times during Dragonfly’s daily flight. The low wind speeds expected for dust devils on Titan mean they will pose little to no hazard to the mission. However, Dragonfly will spend most of its time on the ground, including during Titan’s midday when vortices are most likely to be active, and so encounters will probably occur on the ground every few Earth hours instead. In this case, they will likely resemble encounters on Mars by landed spacecraft. Even then, though, the imagery and meteorological data collected by Dragonfly during encounters may break new ground in aeolian studies by showing how they operate in a new aerodynamic environment.

Titan with Mimas in the foreground, as seen by Cassini on June 16, 2011. Like Earth and Mars, a new study suggests that Titan has dust devils. Image via NASA/ JPL-Caltech/ Space Science Institute/ Sci-News.com.

It’s been known for some time now, thanks to the Cassini mission to Saturn and its moons, that Titan has vast expanses of sand dunes (composed of organic hydrocarbon particles, unlike Earth and Mars). Winds on Titan are typically rather weak, but the dune particles do get transported around, and dust devils might be an ideal mechanism for that to happen. As Brian Jackson, a planetary scientist at BSU, said in a statement:

Winds at the surface of Titan are usually very weak. Unless there is a big storm rolling through, there’s probably not that much wind, and so dust devils may be one of the main dust transport mechanisms on Titan, if they exist.

So far, dust devils haven’t actually been seen yet on Titan, but meteorological models, based on data from the Huygens probe which landed on Titan in 2005, suggest they should be possible. Jackson said:

When we plug the numbers in for how much dust the dust devil ought to lift based on the wind speeds we see, they seem to be able to lift more dust than we would expect. There may be some other mechanism which is helping them pull this dust, or the equations are just wrong.

Artist’s concept of Dragonfly soaring over Titan’s surface. Image via NASA/ JHUAPL/ NPR.

On Earth, dust devils are very common (I remember even being briefly caught in a small one when I was a kid). In order to get more insight into how earthly dust devils form, Jackson and his colleagues studied ones in southeastern Oregon’s Alvord Desert, using small airborne drones carrying meteorological instruments. Those findings can be compared with observations of dust devils on Mars. According to Jackson:

We can watch dust devils skitter across the surface of Mars and see what their internal structure is like, but that doesn’t tell us how much dust they are lifting. Mars’ atmosphere is really, really dusty and dust plays an important role in the climate. Dust devils are probably, if not the dominant mechanism, one of the most important mechanisms for lofting the dust.

Mars’ atmosphere is extremely thin, yet dust devils can still reach a height of 5 miles (8 km). This is especially true during the Martian summer. Mars is very dusty – dust is literally everywhere – and that dust can be carried all over the planet despite the thinness of the atmosphere. The planet even experiences periodic global dust storms.

So how does this apply to Titan?

Titan has a thick atmosphere. It’s even thicker than Earth’s. But it only has one-seventh the gravity of Earth. Because of this, winds on Titan tend to be a lot gentler than those on Earth or even Mars. Jackson said:

It’s just this enormous, puffy atmosphere. When you’ve got that much air it’s hard to get it churning. So you just don’t usually get big winds on the surface of Titan so far as we know.

Since, as far as we know, Titan doesn’t have raging wind storms, smaller dust devils might be a good way to transport the hydrocarbon particles and create the massive dune fields. In this way, Titan would be similar to Mars, even though there are such large differences in atmospheric density and composition, wind speed and sand composition between the two worlds.

It will be a while before we can learn more about dust devils on Titan, and whether they even do actually exist. Dragonfly doesn’t launch until 2026, and won’t arrive at Titan until 2034. The Cassini mission, which ended in 2017, was the most recent to visit Saturn and its moons, with no other missions upcoming until Dragonfly.

Brian Jackson at Boise State University (BSU), the lead author of the new study. Image via BSU.

If Dragonfly does find dust devils, it will be fascinating to compare them to the ones on Earth and Mars. This is especially true since Titan is remarkably similar to Earth in some ways, with its rain, rivers, lakes and seas, albeit composed of liquid methane and ethane instead of water. Combined with the sand dunes, you could almost mistake the landscape seen in images sent back as being on Earth, if it weren’t for the smoggy-looking orange-ish sky. Dust devils would add to that already somewhat eerie – yet oddly reminiscent – alien landscape.

Bottom line: Titan may have dust devils like Earth and Mars, a new study says.

Source: Dust Devils on Titan

Via Phys.org

from EarthSky https://ift.tt/3bMkA0u

What is a fogbow?

View larger at EarthSky Community Photos. | Peter Lowenstein caught this fogbow in Mutare, Zimbabwe, on April 29, 2020. He wrote: “Half-an-hour after the Sun rose behind my house on Wednesday, a beautiful fogbow developed in the middle of a misty morning view from my front veranda. All the conditions were right – bright sunshine from the rear with the Sun less than twenty degrees above the horizon and clearing clouds of mist at the antisolar point. The scene was framed by a beautiful flowering Poinsettia to the left, a lush banana grove to the right, and clear blue sky beginning to appear on top!”

Fogbows – sometimes called white rainbows, cloudbows or ghost rainbows – are made much as rainbows are, from the same configuration of sunlight and moisture. Rainbows happen when the air is filled with raindrops, and you always see a rainbow in the direction opposite the sun. Fogbows are much the same, always opposite the sun, but fogbows are caused by the small droplets inside a fog or cloud rather than larger raindrops.

Look for fogbows in a thin fog when the sun is bright. You might see one when the sun breaks through a fog. Or watch for fogbows over the ocean.

Because the water droplets in fog are so small, fogbows have only weak colors or are colorless.

View at EarthSky Community Photos. | Alan Nicolle in New South Wales, Australia, captured this image on July 16, 2019. He wrote: “I was out geocaching in the outskirts of Broken Hill, when I turned back to see this fogbow developing. I took quite a few photos with the iPhone, and rode back to the car on my bike, but by the time I got back to the car to use my SLR, it had faded.” Thank you, Alan!

Edith Smith in Aberdeenshire, Scotland, captured this fogbow on November 1, 2018. She wrote: “The camera spotted it before I did with eye, as I was too engrossed in foggy conditions.”

Tommy Johnson captured this early morning fogbow near Jonesport, Maine, in August 2016. He wrote: “Early in the morning and blueberry rakers are starting to fill their buckets with the fruit. I called out to them to look at the fogbow, it was the first time any of us had seen one.”

Wonderful fogbow caught by Robyn Smith in New Zealand on the morning of September 19, 2017 “… opposite the foggy sunrise.”

GregDiesel Landscape Photography wrote in October 2015: “Saw my first fogbow / white rainbow. Photo taken with cell phone. Moyock, North Carolina.”

Katherine Keyes Millet captured this fogbow in July 2014 at Winter Island Park in Salem, Massachusetts.

Venus and Jupiter above a fogbow in Blacklough, Dungannon, Ireland. Mars is up there, too, but tough to see. John Fagan captured them all in October 2015.

Eileen Claffey in Brookline, Massachusetts, captured this fogbow over a field in September 2014.

Les Cowley of the great website Atmospheric Optics says:

Look away from the sun and at an angle of 35-40 degrees from your shadow which marks the direction of the antisolar point. Some fogbows have very low contrast so look for small brightenings in the misty background. Once caught, they are unmistakable.

The sun must be less than 30-40 degrees high unless you are on a hill or high up on a ship where the mist and fogbow can be viewed from above.

Fogbows are huge, almost as large as a rainbow and much, much broader.

Look here for Les Cowley’s explanation of how fogbows form.

Thomas Kast in Finland captured this fogbow in 2013. He wrote: “In this rather cold August night (+8C [46F]) there was patchy fog, especially in open fields. This lake remained clear for a long time. At one point I saw this white bow with moon in waning gibbous phase behind me.”

Jim Grant caught this fogbow over Sunset Cliffs in San Diego. He wrote: “The skies were sunny and clear, and then the fog rolled in, and with it this beautiful fogbow.”

Lynton Brown of Australia captured this fogbow over a barren field in the autumn of 2012.

Bottom line: Fogbows are made by much the same process as rainbows, but with the small water droplets inside a fog instead of larger raindrops. Because the water droplets in fog are so small, fogbows have only weak colors or are colorless.

from EarthSky https://ift.tt/2RuWZ9W

View larger at EarthSky Community Photos. | Peter Lowenstein caught this fogbow in Mutare, Zimbabwe, on April 29, 2020. He wrote: “Half-an-hour after the Sun rose behind my house on Wednesday, a beautiful fogbow developed in the middle of a misty morning view from my front veranda. All the conditions were right – bright sunshine from the rear with the Sun less than twenty degrees above the horizon and clearing clouds of mist at the antisolar point. The scene was framed by a beautiful flowering Poinsettia to the left, a lush banana grove to the right, and clear blue sky beginning to appear on top!”

Fogbows – sometimes called white rainbows, cloudbows or ghost rainbows – are made much as rainbows are, from the same configuration of sunlight and moisture. Rainbows happen when the air is filled with raindrops, and you always see a rainbow in the direction opposite the sun. Fogbows are much the same, always opposite the sun, but fogbows are caused by the small droplets inside a fog or cloud rather than larger raindrops.

Look for fogbows in a thin fog when the sun is bright. You might see one when the sun breaks through a fog. Or watch for fogbows over the ocean.

Because the water droplets in fog are so small, fogbows have only weak colors or are colorless.

View at EarthSky Community Photos. | Alan Nicolle in New South Wales, Australia, captured this image on July 16, 2019. He wrote: “I was out geocaching in the outskirts of Broken Hill, when I turned back to see this fogbow developing. I took quite a few photos with the iPhone, and rode back to the car on my bike, but by the time I got back to the car to use my SLR, it had faded.” Thank you, Alan!

Edith Smith in Aberdeenshire, Scotland, captured this fogbow on November 1, 2018. She wrote: “The camera spotted it before I did with eye, as I was too engrossed in foggy conditions.”

Tommy Johnson captured this early morning fogbow near Jonesport, Maine, in August 2016. He wrote: “Early in the morning and blueberry rakers are starting to fill their buckets with the fruit. I called out to them to look at the fogbow, it was the first time any of us had seen one.”

Wonderful fogbow caught by Robyn Smith in New Zealand on the morning of September 19, 2017 “… opposite the foggy sunrise.”

GregDiesel Landscape Photography wrote in October 2015: “Saw my first fogbow / white rainbow. Photo taken with cell phone. Moyock, North Carolina.”

Katherine Keyes Millet captured this fogbow in July 2014 at Winter Island Park in Salem, Massachusetts.

Venus and Jupiter above a fogbow in Blacklough, Dungannon, Ireland. Mars is up there, too, but tough to see. John Fagan captured them all in October 2015.

Eileen Claffey in Brookline, Massachusetts, captured this fogbow over a field in September 2014.

Les Cowley of the great website Atmospheric Optics says:

Look away from the sun and at an angle of 35-40 degrees from your shadow which marks the direction of the antisolar point. Some fogbows have very low contrast so look for small brightenings in the misty background. Once caught, they are unmistakable.

The sun must be less than 30-40 degrees high unless you are on a hill or high up on a ship where the mist and fogbow can be viewed from above.

Fogbows are huge, almost as large as a rainbow and much, much broader.

Look here for Les Cowley’s explanation of how fogbows form.

Thomas Kast in Finland captured this fogbow in 2013. He wrote: “In this rather cold August night (+8C [46F]) there was patchy fog, especially in open fields. This lake remained clear for a long time. At one point I saw this white bow with moon in waning gibbous phase behind me.”

Jim Grant caught this fogbow over Sunset Cliffs in San Diego. He wrote: “The skies were sunny and clear, and then the fog rolled in, and with it this beautiful fogbow.”

Lynton Brown of Australia captured this fogbow over a barren field in the autumn of 2012.

Bottom line: Fogbows are made by much the same process as rainbows, but with the small water droplets inside a fog instead of larger raindrops. Because the water droplets in fog are so small, fogbows have only weak colors or are colorless.

from EarthSky https://ift.tt/2RuWZ9W

How family stories help children weather hard times

Stories of family members — who preserved by simply putting one foot in front of the other and by maintaining loving bonds — reassure children that their family will also find a way to get through a situation, says Emory psychologist Robyn Fivush. (Getty Images)

By Carol Clark

In times of great stress, stories sustain us, says Robyn Fivush, director of the Family Narratives Lab in Emory’s Department of Psychology.

Family reminiscing is especially important, says Fivush, who is also director of Emory’s Institute for the Liberal Arts. When children learn family stories it creates a shared history, strengthens emotional bonds and helps them make sense of their experiences when something senseless happens — like the current global pandemic.

“When we don’t know what to do, we look for stories about how people have coped in the past,” Fivush says. “You can see that happening in the media now, in articles comparing today to historical events, like the 1918 flu pandemic and 9/11.”

She sums up the 9/11 narrative in the United States: “A horrific event happened; we were attacked. But we came together as a nation, persevered and rose back up together.”

Such narratives help build a shared capacity for resilience. “That’s true for nations and it’s true for families,” Fivush says.

Over decades of research, Fivush and Emory psychologist Marshall Duke developed a scale to measure how much children know about their family histories. Using this scale, they conducted a study that began just before 9/11 and continued for two years. “We found that in families that talked in more coherent and emotionally open ways about challenging family events with 10- to 12-year-olds, the children coped better over the two-year period than in families telling less emotionally expressive and coherent stories about their challenges,” Fivush says.

The families in the study were all comparable, middle-class, two-parent households.

Standardized measures showed that children in the families that told the more coherent family narratives had better self-esteem, higher levels of social competence, higher quality friendships, and less anxiety and stress. They also had fewer behavioral problems, as reported by parents.

Tips for telling family stories 

For families under quarantine together, opportunities abound to weave family stories into conversation, Fivush says. The stories need to be tailored to different ages, she adds, so that children are emotionally and cognitively able to understand them.

Elementary school children, for example, are not ready to digest complex family stories. “With younger kids, it’s really more about helping them structure their own experiences into stories that help them process their feelings,” Fivush says. “You want to start by asking them non-judgmental, open-ended questions like: ‘Why do you think you were upset yesterday? What could you have done to make yourself feel better? What can we do about this?'"

She uses an example of a little girl who left her favorite storybook at her school and was worried that it wasn’t going to be there when she went back. A mother could tell a story about how she left a favorite toy somewhere when she was little but later her father took her back and they found it.

“Tell them a story from your own life that provides a model for how everybody forgets things, but you can get them back,” Fivush says. “Or, ‘My brother used to tease me a lot, too. But now he’s your Uncle Bill and we love each other.’ Parents are identity figures. Little kids are fascinated by stories about their parents when they were little.”

Ultimately, the goal is to help children construct a coherent story that validates their feelings while helping them think of resolutions.

“Particularly with very young kids, don’t make assumptions about what they may be upset or sad about,” Fivush says. “You may be surprised. Stay open to what your children of all ages may be experiencing.”

Middle school children are starting to have more of an ability to understand the bigger picture. “By the age of 10, children are thinking in the abstract and because of that, they are likely to be anxious about the future,” Fivush says.

By this stage, children begin to understand stories on a deeper level. It’s not that every story needs a happy ending or a silver lining, Fivush stresses. “You can explain to your child, ‘We don’t know yet how this story is going to end but let me tell you about some challenging times I got through, or your grandparents got through.’”

Examples of family members — who preserved by simply putting one foot in front of the other and by maintaining loving bonds — reassure children that their family will also find a way to get through a situation.

When they reach adolescence, children are especially vulnerable. “High school is a time when children start to really think about themselves as a person and what their life is going to be like,” Fivush says. “They are mulling big questions, like ‘Who am I? What are my passions?’ And now the pandemic has pulled the rug out from under them.”

By the age of 16, parents can start talking to a teen-ager about their own vulnerabilities as people and as parents. “Emphasize how you can build strength together, as a family,” Fivush says. She suggests finding ways of giving teen-agers a role in supporting younger children in positive ways.

“Human beings are really altruistic and empathetic. We feel good when we help other people, particularly people that we love,” Fivush says. “That’s going to make every family member feel better about themselves and about each other.”

Silly, funny family stories are also valuable, along with small touchpoints about the past that emerge spontaneously, Fivush says. “When you’re cooking together with your children it’s a perfect time to say, ‘When I was a little girl, my mother taught me how to cook this dish. We used to have post roast every Friday and I would peel the carrots.’”

Adolescents are especially hungry for these kinds of stories, she adds. “If they roll their eyes, so be it, they’re still listening,” Fivush says. “It’s the really mundane, everyday stories that reassure them that life is stable. It provides a sense of continuity, of enduring relationships and values. They need to know that they come from a long line of people who are strong, who are resilient, who are brave. And who can cook. The definition of who they are is not just something independent and autonomous, spun from nowhere. It’s embedded in a long, intergenerational family story.”

Related:
Stories your parents should have told you
Psychologists document the age our earliest memories fade

from eScienceCommons https://ift.tt/2SiTSVM

Stories of family members — who preserved by simply putting one foot in front of the other and by maintaining loving bonds — reassure children that their family will also find a way to get through a situation, says Emory psychologist Robyn Fivush. (Getty Images)

By Carol Clark

In times of great stress, stories sustain us, says Robyn Fivush, director of the Family Narratives Lab in Emory’s Department of Psychology.

Family reminiscing is especially important, says Fivush, who is also director of Emory’s Institute for the Liberal Arts. When children learn family stories it creates a shared history, strengthens emotional bonds and helps them make sense of their experiences when something senseless happens — like the current global pandemic.

“When we don’t know what to do, we look for stories about how people have coped in the past,” Fivush says. “You can see that happening in the media now, in articles comparing today to historical events, like the 1918 flu pandemic and 9/11.”

She sums up the 9/11 narrative in the United States: “A horrific event happened; we were attacked. But we came together as a nation, persevered and rose back up together.”

Such narratives help build a shared capacity for resilience. “That’s true for nations and it’s true for families,” Fivush says.

Over decades of research, Fivush and Emory psychologist Marshall Duke developed a scale to measure how much children know about their family histories. Using this scale, they conducted a study that began just before 9/11 and continued for two years. “We found that in families that talked in more coherent and emotionally open ways about challenging family events with 10- to 12-year-olds, the children coped better over the two-year period than in families telling less emotionally expressive and coherent stories about their challenges,” Fivush says.

The families in the study were all comparable, middle-class, two-parent households.

Standardized measures showed that children in the families that told the more coherent family narratives had better self-esteem, higher levels of social competence, higher quality friendships, and less anxiety and stress. They also had fewer behavioral problems, as reported by parents.

Tips for telling family stories 

For families under quarantine together, opportunities abound to weave family stories into conversation, Fivush says. The stories need to be tailored to different ages, she adds, so that children are emotionally and cognitively able to understand them.

Elementary school children, for example, are not ready to digest complex family stories. “With younger kids, it’s really more about helping them structure their own experiences into stories that help them process their feelings,” Fivush says. “You want to start by asking them non-judgmental, open-ended questions like: ‘Why do you think you were upset yesterday? What could you have done to make yourself feel better? What can we do about this?'"

She uses an example of a little girl who left her favorite storybook at her school and was worried that it wasn’t going to be there when she went back. A mother could tell a story about how she left a favorite toy somewhere when she was little but later her father took her back and they found it.

“Tell them a story from your own life that provides a model for how everybody forgets things, but you can get them back,” Fivush says. “Or, ‘My brother used to tease me a lot, too. But now he’s your Uncle Bill and we love each other.’ Parents are identity figures. Little kids are fascinated by stories about their parents when they were little.”

Ultimately, the goal is to help children construct a coherent story that validates their feelings while helping them think of resolutions.

“Particularly with very young kids, don’t make assumptions about what they may be upset or sad about,” Fivush says. “You may be surprised. Stay open to what your children of all ages may be experiencing.”

Middle school children are starting to have more of an ability to understand the bigger picture. “By the age of 10, children are thinking in the abstract and because of that, they are likely to be anxious about the future,” Fivush says.

By this stage, children begin to understand stories on a deeper level. It’s not that every story needs a happy ending or a silver lining, Fivush stresses. “You can explain to your child, ‘We don’t know yet how this story is going to end but let me tell you about some challenging times I got through, or your grandparents got through.’”

Examples of family members — who preserved by simply putting one foot in front of the other and by maintaining loving bonds — reassure children that their family will also find a way to get through a situation.

When they reach adolescence, children are especially vulnerable. “High school is a time when children start to really think about themselves as a person and what their life is going to be like,” Fivush says. “They are mulling big questions, like ‘Who am I? What are my passions?’ And now the pandemic has pulled the rug out from under them.”

By the age of 16, parents can start talking to a teen-ager about their own vulnerabilities as people and as parents. “Emphasize how you can build strength together, as a family,” Fivush says. She suggests finding ways of giving teen-agers a role in supporting younger children in positive ways.

“Human beings are really altruistic and empathetic. We feel good when we help other people, particularly people that we love,” Fivush says. “That’s going to make every family member feel better about themselves and about each other.”

Silly, funny family stories are also valuable, along with small touchpoints about the past that emerge spontaneously, Fivush says. “When you’re cooking together with your children it’s a perfect time to say, ‘When I was a little girl, my mother taught me how to cook this dish. We used to have post roast every Friday and I would peel the carrots.’”

Adolescents are especially hungry for these kinds of stories, she adds. “If they roll their eyes, so be it, they’re still listening,” Fivush says. “It’s the really mundane, everyday stories that reassure them that life is stable. It provides a sense of continuity, of enduring relationships and values. They need to know that they come from a long line of people who are strong, who are resilient, who are brave. And who can cook. The definition of who they are is not just something independent and autonomous, spun from nowhere. It’s embedded in a long, intergenerational family story.”

Related:
Stories your parents should have told you
Psychologists document the age our earliest memories fade

from eScienceCommons https://ift.tt/2SiTSVM

April’s 2nd first quarter moon on April 30

Above photo: First quarter moon as captured by Duke Marsh in Indiana. Thank you, Duke!

Tonight – April 30, 2020 – the moon is at or near its first quarter phase, as darkness falls around the world. At first quarter moon, the moon is 90 degrees east of the sun on the sky’s dome, and its disk is half-illuminated by sunshine. About one week from now – on May 7, 2020 – the moon will turn full when it’s 180 degrees from the sun in our sky, and its disk is totally illuminated by sunshine.

Read more: Last full moon supermoon of 2020

Moon phase diagram with sun at right: 1) new moon, 2) waxing crescent, 3) first quarter, 4) waxing gibbous, 5) full moon, 6) waning gibbous, 7) last quarter, 8) waning crescent. At first quarter phase, the sun-Earth-moon angle = 90 degrees, with the Earth at the vertex of this right angle.

This first quarter moon presents the second of two April 2020 first quarter moons, with the first one falling on April 1, 2020. It’s the only time this year that two first quarter moons take place in a single calendar month, though the event probably won’t generate much fanfare. Later on this year, two full moons will occur in October 2020, and the second of these two full moons will be celebrated by many people around the world as a Blue Moon.

In the year 2020, there are 13 first quarter moons and 13 full moons. Therefore, the month of April has two first quarter moons, and the month of October has two full moons. Moon phases via Astropixels.

The second first quarter moon of April 2020 comes on April 30, 2020, at 20:38 UTC. In United States time zones, that gives the local clock time for the first quarter moon as 4:38 p.m. EDT, 3:38 p.m. CDT, 2:38 p.m. MDT and 1:38 p.m. PDT. Although the moon will be slightly past its first quarter phase as darkness falls over North America on April 30, you can still see the moon at the instant of its first quarter phase in a daytime sky.

Click on this Sunrise Sunset Calendar to find out the moon’s rising time, remembering to check the moonrise and moonset box.

This first quarter moon shines in front of the constellation Cancer the Crab, one of the faintest constellations of the zodiac. Because the first quarter moon is 90 degrees east of the sun on the sky’s dome, the first quarter moon shows you where the sun will be shining in front of the constellations of the zodiac some 3 months (or 1/4 year) from now: on or near July 30, 2020.

Click on Heavens-Above to know which constellation of the zodiac backdrops the moon.

Chart of the constellation Cancer via International Astronomical Association (IAU).

The sun will pass in front of the constellation Cancer from July 20 to August 10, 2020. Of course, the constellation Cancer will then be invisible because it’ll be rising and setting with the sun, and will be lost in the solar glare.

Read more: Sun in zodiac constellations, 2020

Bottom line: Tonight – April 30, 2020 – enjoy the second of two April first quarter moons, as it lights up Cancer the Crab, one of the faintest constellations of the zodiac.

from EarthSky https://ift.tt/3cS3pL4

Above photo: First quarter moon as captured by Duke Marsh in Indiana. Thank you, Duke!

Tonight – April 30, 2020 – the moon is at or near its first quarter phase, as darkness falls around the world. At first quarter moon, the moon is 90 degrees east of the sun on the sky’s dome, and its disk is half-illuminated by sunshine. About one week from now – on May 7, 2020 – the moon will turn full when it’s 180 degrees from the sun in our sky, and its disk is totally illuminated by sunshine.

Read more: Last full moon supermoon of 2020

Moon phase diagram with sun at right: 1) new moon, 2) waxing crescent, 3) first quarter, 4) waxing gibbous, 5) full moon, 6) waning gibbous, 7) last quarter, 8) waning crescent. At first quarter phase, the sun-Earth-moon angle = 90 degrees, with the Earth at the vertex of this right angle.

This first quarter moon presents the second of two April 2020 first quarter moons, with the first one falling on April 1, 2020. It’s the only time this year that two first quarter moons take place in a single calendar month, though the event probably won’t generate much fanfare. Later on this year, two full moons will occur in October 2020, and the second of these two full moons will be celebrated by many people around the world as a Blue Moon.

In the year 2020, there are 13 first quarter moons and 13 full moons. Therefore, the month of April has two first quarter moons, and the month of October has two full moons. Moon phases via Astropixels.

The second first quarter moon of April 2020 comes on April 30, 2020, at 20:38 UTC. In United States time zones, that gives the local clock time for the first quarter moon as 4:38 p.m. EDT, 3:38 p.m. CDT, 2:38 p.m. MDT and 1:38 p.m. PDT. Although the moon will be slightly past its first quarter phase as darkness falls over North America on April 30, you can still see the moon at the instant of its first quarter phase in a daytime sky.

Click on this Sunrise Sunset Calendar to find out the moon’s rising time, remembering to check the moonrise and moonset box.

This first quarter moon shines in front of the constellation Cancer the Crab, one of the faintest constellations of the zodiac. Because the first quarter moon is 90 degrees east of the sun on the sky’s dome, the first quarter moon shows you where the sun will be shining in front of the constellations of the zodiac some 3 months (or 1/4 year) from now: on or near July 30, 2020.

Click on Heavens-Above to know which constellation of the zodiac backdrops the moon.

Chart of the constellation Cancer via International Astronomical Association (IAU).

The sun will pass in front of the constellation Cancer from July 20 to August 10, 2020. Of course, the constellation Cancer will then be invisible because it’ll be rising and setting with the sun, and will be lost in the solar glare.

Read more: Sun in zodiac constellations, 2020

Bottom line: Tonight – April 30, 2020 – enjoy the second of two April first quarter moons, as it lights up Cancer the Crab, one of the faintest constellations of the zodiac.

from EarthSky https://ift.tt/3cS3pL4

First-ever comprehensive geologic map of the moon

The animation above shows a rotating globe of the new Unified Geologic Map of the Moon with shaded topography from NASA’s LOLA mission to the moon (LOLA stands for Lunar Orbiter Laser Altimeter).

You can directly download the new moon map at its website: https://astrogeology.usgs.gov/search/map/Moon/Geology/Unified_Geologic_Map_of_the_Moon_GIS.

[NOTE ADDED APRIL 29: This USGS website, where you can download the map, was down when we checked it earlier today; keep trying]

The U.S. Geologic Survey (USGS) announced the new Unified Geologic Map of the Moon on April 20, 2020. They said it shows the moon’s surface geology, with rock layers and craters charted “in great detail.” The map is a synthesis of six Apollo-era regional geologic maps, updated with data from more recent moon missions.

USGS said it’s designed to serve as “the definitive blueprint” for lunar science and future human missions to the moon, and to be used by the international scientific community, educators and the public at large.

View larger. | The new Unified Geologic Map of the moon. It shows orthographic projections – that is, representations of 3-dimensional objects on a 2-dimensional map – of the geology of the moon’s near side (left) and far side (right). This geologic map is a synthesis of 6 Apollo-era regional geologic maps, updated based on data from recent satellite missions. It will serve as a reference for lunar science and future human missions to the moon. Image via NASA/ GSFC /USGS.

To create the new digital map, scientists used information from six Apollo-era regional maps along with updated information from recent satellite missions to the moon.

The existing historical maps were redrawn to align them with the modern data sets, thus preserving previous observations and interpretations. Along with merging new and old data, USGS researchers also developed a unified description of the stratigraphy, or rock layers, of the moon. This resolved issues from previous maps where rock names, descriptions and ages were sometimes inconsistent.

Corey Fortezzo, USGS geologist, is lead author of the study, published by the Lunar and Planetary Institute. Fortezzo said in a statement:

This map is a culmination of a decades-long project. It provides vital information for new scientific studies by connecting the exploration of specific sites on the moon with the rest of the lunar surface.

Topography for the north and south poles was supplemented with data from NASA’s Lunar Orbiter Laser Altimeter (LOLA), a robotic spacecraft currently orbiting the moon. Data collected by the Lunar Reconnaisance Orbiter (LRO) have been described as essential for planning NASA’s future human and robotic missions to the Moon. Its detailed mapping program is identifying safe landing sites, locating potential resources on the moon, characterizing the radiation environment, and demonstrating new technologies.

Elevation data for the moon’s equatorial region came from stereo observations collected by the Terrain Camera on the recent SELENE (Selenological and Engineering Explorer) mission led by JAXA, the Japan Aerospace Exploration Agency.

Learn more at the Unified Geologic Map of the Moon website.

Bottom line: The first-ever comprehensive geological map of the entire moon has been created.

Source: Release of the digital unified global geologic map of the moon at 1:5,000,000-scale

Via USGS

More from USGS

from EarthSky https://ift.tt/2KLe2mQ

The animation above shows a rotating globe of the new Unified Geologic Map of the Moon with shaded topography from NASA’s LOLA mission to the moon (LOLA stands for Lunar Orbiter Laser Altimeter).

You can directly download the new moon map at its website: https://astrogeology.usgs.gov/search/map/Moon/Geology/Unified_Geologic_Map_of_the_Moon_GIS.

[NOTE ADDED APRIL 29: This USGS website, where you can download the map, was down when we checked it earlier today; keep trying]

The U.S. Geologic Survey (USGS) announced the new Unified Geologic Map of the Moon on April 20, 2020. They said it shows the moon’s surface geology, with rock layers and craters charted “in great detail.” The map is a synthesis of six Apollo-era regional geologic maps, updated with data from more recent moon missions.

USGS said it’s designed to serve as “the definitive blueprint” for lunar science and future human missions to the moon, and to be used by the international scientific community, educators and the public at large.

View larger. | The new Unified Geologic Map of the moon. It shows orthographic projections – that is, representations of 3-dimensional objects on a 2-dimensional map – of the geology of the moon’s near side (left) and far side (right). This geologic map is a synthesis of 6 Apollo-era regional geologic maps, updated based on data from recent satellite missions. It will serve as a reference for lunar science and future human missions to the moon. Image via NASA/ GSFC /USGS.

To create the new digital map, scientists used information from six Apollo-era regional maps along with updated information from recent satellite missions to the moon.

The existing historical maps were redrawn to align them with the modern data sets, thus preserving previous observations and interpretations. Along with merging new and old data, USGS researchers also developed a unified description of the stratigraphy, or rock layers, of the moon. This resolved issues from previous maps where rock names, descriptions and ages were sometimes inconsistent.

Corey Fortezzo, USGS geologist, is lead author of the study, published by the Lunar and Planetary Institute. Fortezzo said in a statement:

This map is a culmination of a decades-long project. It provides vital information for new scientific studies by connecting the exploration of specific sites on the moon with the rest of the lunar surface.

Topography for the north and south poles was supplemented with data from NASA’s Lunar Orbiter Laser Altimeter (LOLA), a robotic spacecraft currently orbiting the moon. Data collected by the Lunar Reconnaisance Orbiter (LRO) have been described as essential for planning NASA’s future human and robotic missions to the Moon. Its detailed mapping program is identifying safe landing sites, locating potential resources on the moon, characterizing the radiation environment, and demonstrating new technologies.

Elevation data for the moon’s equatorial region came from stereo observations collected by the Terrain Camera on the recent SELENE (Selenological and Engineering Explorer) mission led by JAXA, the Japan Aerospace Exploration Agency.

Learn more at the Unified Geologic Map of the Moon website.

Bottom line: The first-ever comprehensive geological map of the entire moon has been created.

Source: Release of the digital unified global geologic map of the moon at 1:5,000,000-scale

Via USGS

More from USGS

from EarthSky https://ift.tt/2KLe2mQ

Coronavirus genome like a shipping label that lets epidemiologists track where it’s been

The steady rate of genetic changes lets researchers recreate how a virus has travelled. Image via nextstrain.org.

By Bert Ely, University of South Carolina and Taylor Carter, University of South Carolina

Following the coronavirus’s spread through the population – and anticipating its next move – is an important part of the public health response to the new disease, especially since containment is our only defense so far.

Just looking at an infected person doesn’t tell you where their version of the coronavirus came from, and SARS-CoV-2 doesn’t have a bar code you can scan to allow you to track its travel history. However, its genetic sequence is almost as good for providing some insight into where the virus has been.

An organism’s genome is its complete genetic instructions. You can think of a genome as a book, containing words made up of letters. Each “letter” in the genome is a molecule called a nucleotide – in shorthand, an A, G, C, T or U.

Mutations can occur every time the virus replicates its genome, so that over time mutations accumulate in the viral genome. For example, in place of the “word” CAT, the new virus has GAT. The virus carries these minor modifications as it moves from one person to the next host.

These mutations behave like a passport stamp. No matter where you go next, previous stamps in your passport still show where you’ve been.

Molecular geneticists like us can use this information to construct family trees for the coronavirus. That allows us to trace the routes the virus has traveled through space and time and start to answer questions like how quickly and easily does it spread from one person to another?

In early February, a laboratory technician works on virus samples from patients sick in Wuhan, China. Image via STR/ AFP/ Getty Images

Individual patient data help paint a big picture

Online databases have been collecting SARS-CoV-2 genomic nucleotide sequences since mid-December. Whenever a patient tests positive for SARS-CoV-2, a lab can determine the genome sequence of the infecting virus and upload it. As of late April 2020 more than 1,500 genome sequence samples have been deposited in GenBank, a publicly available database run by the National Institutes of Health, and more than 3,000 are in GISAID, the open-access Global Initiative on Sharing All Influenza Data.

Since each sequence is from a patient who is in a specific place in the world, these viral genome sequences allow scientists to compare them and track where the virus has been. The more similar the sequences from two particular viruses are, the more closely related they are and the more recently they’ve shared a common ancestor. The first SARS-CoV-2 genomic sequence uploaded to the GISAID’s website was collected from a patient in early December 2019.

Of course, the viral mutations themselves do not tell researchers which country they happened in. But since the databases record where particular patterns of mutations have been observed, scientists can determine the route that each viral strain has taken. The global map tracks the movement of the virus around the world.

The data recorded from thousands of patients show that SARS-Cov-2 originated in Wuhan, China, and spread from there to the rest of the world.

The SARS-CoV-2 phylogenetic tree, the family tree that connects all the sequenced coronavirus samples worldwide. The colors denote regional ‘branches’ of the tree. Image via nextstrain.org.

Building maps out of sequences

The genetic data can play a big role in cracking public health mysteries, like how the coronavirus has spread through the United States.

For example, a traveler from Wuhan arrived in Seattle on January 15 and tested positive for the virus on January 20.

On February 28, scientists sequenced a virus sample from an American patient in Seattle and found its mutation signature matched that of the virus from the Wuhan traveler, plus three new mutations. GISAID has estimated the mutation rate at about 0.45 mutations per genome per week – so three mutations between the January 20 case and the February 28 case fits that rate.

Based on the three new mutations, this version of the virus had been multiplying undetected for about five weeks in the Seattle area. Since each infected person can infect several other people without experiencing any symptoms themselves, the virus could have spread to more than 100 people in five weeks.

Using the genome sequences to link the virus from the January 15 traveler from Wuhan with the Washington-based patient from the end of February alerted Washington state officials that the virus was silently spreading through the population. This undetected spreading of the virus in Seattle and elsewhere is one of the primary reasons public health officials are calling for the public to stay home as much as possible.

Another study detailed the path the virus took as it moved from Wuhan to Shanghai to Germany to Italy to Mexico, stowing away in infected travelers. This study tracked infected individuals and compared their viral genomic sequences. Since researchers could compare the viral mutations to those in known locations at specific times, they were able to map out the phylogenetic tree, the family tree that shows how the various virus genome sequences are related.

Using the GISAID estimated mutation rate and the phylogenetic tree, scientists think the first time the coronavirus infected a person likely occurred in Wuhan in November or early December 2019.

If the virus had been around much longer, the viruses of the first known patients would have had a larger variety of mutations than they did.

The coronavirus can travel the world by hitching a ride in an infected traveler. Image via Anadolu Agency/ Getty Images.

Still tracking and learning from the sequences

The analysis of viral genomic sequences will continue to be a valuable tool for tracking and containing the spread of SARS-CoV-2.

For instance, sequencing the genome of a virus from a newly infected patient could tell you if it is a virus that has been circulating in the area for a while, or if it is a new introduction from elsewhere.

Someone who’d been in northern Italy before travel restrictions were in place brought the virus to Iceland. That initial outbreak was contained fairly quickly, but then new forms of the virus were introduced from elsewhere in Europe.

A new study pending peer-review indicates that California also had multiple introduction events with distinct viral lineages. For California, knowledge of the frequency of new introductions would be an important factor to consider as officials devise ways to contain the virus.

Viral genome sequences can be informative in other ways as well. Eventually, researchers may find that some forms of the virus are more virulent than others. In that case, the sequence of the viral genome could help physicians decide which treatment would be best for a particular patient.

Bottom line: Every time the coronavirus copies itself, it makes mistakes, creating a trail that researchers can use to build a family tree with information about where it’s traveled, and when.

Bert Ely, Professor of Biological Sciences, University of South Carolina and Taylor Carter, Ph.D. Student in Biological Sciences, University of South Carolina

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

from EarthSky https://ift.tt/3f4NomT

The steady rate of genetic changes lets researchers recreate how a virus has travelled. Image via nextstrain.org.

By Bert Ely, University of South Carolina and Taylor Carter, University of South Carolina

Following the coronavirus’s spread through the population – and anticipating its next move – is an important part of the public health response to the new disease, especially since containment is our only defense so far.

Just looking at an infected person doesn’t tell you where their version of the coronavirus came from, and SARS-CoV-2 doesn’t have a bar code you can scan to allow you to track its travel history. However, its genetic sequence is almost as good for providing some insight into where the virus has been.

An organism’s genome is its complete genetic instructions. You can think of a genome as a book, containing words made up of letters. Each “letter” in the genome is a molecule called a nucleotide – in shorthand, an A, G, C, T or U.

Mutations can occur every time the virus replicates its genome, so that over time mutations accumulate in the viral genome. For example, in place of the “word” CAT, the new virus has GAT. The virus carries these minor modifications as it moves from one person to the next host.

These mutations behave like a passport stamp. No matter where you go next, previous stamps in your passport still show where you’ve been.

Molecular geneticists like us can use this information to construct family trees for the coronavirus. That allows us to trace the routes the virus has traveled through space and time and start to answer questions like how quickly and easily does it spread from one person to another?

In early February, a laboratory technician works on virus samples from patients sick in Wuhan, China. Image via STR/ AFP/ Getty Images

Individual patient data help paint a big picture

Online databases have been collecting SARS-CoV-2 genomic nucleotide sequences since mid-December. Whenever a patient tests positive for SARS-CoV-2, a lab can determine the genome sequence of the infecting virus and upload it. As of late April 2020 more than 1,500 genome sequence samples have been deposited in GenBank, a publicly available database run by the National Institutes of Health, and more than 3,000 are in GISAID, the open-access Global Initiative on Sharing All Influenza Data.

Since each sequence is from a patient who is in a specific place in the world, these viral genome sequences allow scientists to compare them and track where the virus has been. The more similar the sequences from two particular viruses are, the more closely related they are and the more recently they’ve shared a common ancestor. The first SARS-CoV-2 genomic sequence uploaded to the GISAID’s website was collected from a patient in early December 2019.

Of course, the viral mutations themselves do not tell researchers which country they happened in. But since the databases record where particular patterns of mutations have been observed, scientists can determine the route that each viral strain has taken. The global map tracks the movement of the virus around the world.

The data recorded from thousands of patients show that SARS-Cov-2 originated in Wuhan, China, and spread from there to the rest of the world.

The SARS-CoV-2 phylogenetic tree, the family tree that connects all the sequenced coronavirus samples worldwide. The colors denote regional ‘branches’ of the tree. Image via nextstrain.org.

Building maps out of sequences

The genetic data can play a big role in cracking public health mysteries, like how the coronavirus has spread through the United States.

For example, a traveler from Wuhan arrived in Seattle on January 15 and tested positive for the virus on January 20.

On February 28, scientists sequenced a virus sample from an American patient in Seattle and found its mutation signature matched that of the virus from the Wuhan traveler, plus three new mutations. GISAID has estimated the mutation rate at about 0.45 mutations per genome per week – so three mutations between the January 20 case and the February 28 case fits that rate.

Based on the three new mutations, this version of the virus had been multiplying undetected for about five weeks in the Seattle area. Since each infected person can infect several other people without experiencing any symptoms themselves, the virus could have spread to more than 100 people in five weeks.

Using the genome sequences to link the virus from the January 15 traveler from Wuhan with the Washington-based patient from the end of February alerted Washington state officials that the virus was silently spreading through the population. This undetected spreading of the virus in Seattle and elsewhere is one of the primary reasons public health officials are calling for the public to stay home as much as possible.

Another study detailed the path the virus took as it moved from Wuhan to Shanghai to Germany to Italy to Mexico, stowing away in infected travelers. This study tracked infected individuals and compared their viral genomic sequences. Since researchers could compare the viral mutations to those in known locations at specific times, they were able to map out the phylogenetic tree, the family tree that shows how the various virus genome sequences are related.

Using the GISAID estimated mutation rate and the phylogenetic tree, scientists think the first time the coronavirus infected a person likely occurred in Wuhan in November or early December 2019.

If the virus had been around much longer, the viruses of the first known patients would have had a larger variety of mutations than they did.

The coronavirus can travel the world by hitching a ride in an infected traveler. Image via Anadolu Agency/ Getty Images.

Still tracking and learning from the sequences

The analysis of viral genomic sequences will continue to be a valuable tool for tracking and containing the spread of SARS-CoV-2.

For instance, sequencing the genome of a virus from a newly infected patient could tell you if it is a virus that has been circulating in the area for a while, or if it is a new introduction from elsewhere.

Someone who’d been in northern Italy before travel restrictions were in place brought the virus to Iceland. That initial outbreak was contained fairly quickly, but then new forms of the virus were introduced from elsewhere in Europe.

A new study pending peer-review indicates that California also had multiple introduction events with distinct viral lineages. For California, knowledge of the frequency of new introductions would be an important factor to consider as officials devise ways to contain the virus.

Viral genome sequences can be informative in other ways as well. Eventually, researchers may find that some forms of the virus are more virulent than others. In that case, the sequence of the viral genome could help physicians decide which treatment would be best for a particular patient.

Bottom line: Every time the coronavirus copies itself, it makes mistakes, creating a trail that researchers can use to build a family tree with information about where it’s traveled, and when.

Bert Ely, Professor of Biological Sciences, University of South Carolina and Taylor Carter, Ph.D. Student in Biological Sciences, University of South Carolina

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

from EarthSky https://ift.tt/3f4NomT

Breakup of comet ATLAS

View larger. | Image via NASA/ ESA/ D. Jewitt (UCLA), Quanzhi Ye (University of Maryland

On Tuesday (April 28, 2020) the NASA/ESA Hubble Space Telescope released the sharpest views yet of the breakup of comet C/2019 Y4 (ATLAS). The space telescope images reveal roughly 30 fragments of the comet on April 20 – each roughly the size of a house – and 25 pieces on April 23.

Astronomers using the ATLAS (Asteroid Terrestrial-impact Last Alert System) in Hawaii discovered Comet C/2019 Y4 (ATLAS) on December 28, 2019. It brightened quickly until mid-March, and some astronomers initially anticipated that it might be visible to the naked eye in May to become one of the most spectacular comets seen in the last two decades. However, the comet began to get fainter, leading astronomers to speculate that the icy core may be fragmenting, or even disintegrating. By April 11, ATLAS’s fragmentation was confirmed by amateur astronomer Jose de Queiroz, who photographed several pieces of the comet.

Hubble Space Telescope image of comet C/2019 Y4 (ATLAS) on April 20, 2020. Image via NASA/ ESA/ STScI/ D. Jewitt (UCLA).

Hubble Space Telescope image of comet C/2019 Y4 (ATLAS) on April 23, 2020. Image via NASA/ ESA/ STScI/ D. Jewitt (UCLA).

Hubble’s April 20 and 23 observations of the comet’s breakup show that the broken fragments enveloped in a sunlight-swept tail of cometary dust. These images provide further evidence that comet fragmentation is probably common and might even be the dominant mechanism by which the solid, icy nuclei of comets die. UCLA’s David Jewitt is leader of one of two Hubble teams who imaged the doomed comet. He said in a statement:

Their appearance changes substantially between the two days, so much so that it’s quite difficult to connect the dots. I don’t know whether this is because the individual pieces are flashing on and off as they reflect sunlight, acting like twinkling lights on a Christmas tree, or because different fragments appear on different days.

Because comet fragmentation happens quickly and unpredictably, reliable observations are rare, an astronomers remain largely uncertain about the cause of fragmentation. University of Maryland’s Quanzhi Ye, leader of the second Hubble observing team, said:

This is really exciting — both because such events are super cool to watch and because they do not happen very often. Most comets that fragment are too dim to see. Events at such scale only happen once or twice a decade.

Hubble’s crisp images may yield new clues to the breakup. The telescope has distinguished pieces as small as the size of a house. Before the breakup, the entire nucleus may have been no more than the length of two football fields.

The disintegrating comet was approximately 91 million miles (146 million km) from Earth when the latest Hubble observations were taken. If any of it survives, the comet will make its closest approach to Earth on May 23 at a distance of about 72 million miles (116 million km), and eight days later it will skirt past the sun at 25 million miles (40 million km).

Bottom line: New Hubble images show comet ATLAS breaking up.

Via ESA

from EarthSky https://ift.tt/2Ska8FN

View larger. | Image via NASA/ ESA/ D. Jewitt (UCLA), Quanzhi Ye (University of Maryland

On Tuesday (April 28, 2020) the NASA/ESA Hubble Space Telescope released the sharpest views yet of the breakup of comet C/2019 Y4 (ATLAS). The space telescope images reveal roughly 30 fragments of the comet on April 20 – each roughly the size of a house – and 25 pieces on April 23.

Astronomers using the ATLAS (Asteroid Terrestrial-impact Last Alert System) in Hawaii discovered Comet C/2019 Y4 (ATLAS) on December 28, 2019. It brightened quickly until mid-March, and some astronomers initially anticipated that it might be visible to the naked eye in May to become one of the most spectacular comets seen in the last two decades. However, the comet began to get fainter, leading astronomers to speculate that the icy core may be fragmenting, or even disintegrating. By April 11, ATLAS’s fragmentation was confirmed by amateur astronomer Jose de Queiroz, who photographed several pieces of the comet.

Hubble Space Telescope image of comet C/2019 Y4 (ATLAS) on April 20, 2020. Image via NASA/ ESA/ STScI/ D. Jewitt (UCLA).

Hubble Space Telescope image of comet C/2019 Y4 (ATLAS) on April 23, 2020. Image via NASA/ ESA/ STScI/ D. Jewitt (UCLA).

Hubble’s April 20 and 23 observations of the comet’s breakup show that the broken fragments enveloped in a sunlight-swept tail of cometary dust. These images provide further evidence that comet fragmentation is probably common and might even be the dominant mechanism by which the solid, icy nuclei of comets die. UCLA’s David Jewitt is leader of one of two Hubble teams who imaged the doomed comet. He said in a statement:

Their appearance changes substantially between the two days, so much so that it’s quite difficult to connect the dots. I don’t know whether this is because the individual pieces are flashing on and off as they reflect sunlight, acting like twinkling lights on a Christmas tree, or because different fragments appear on different days.

Because comet fragmentation happens quickly and unpredictably, reliable observations are rare, an astronomers remain largely uncertain about the cause of fragmentation. University of Maryland’s Quanzhi Ye, leader of the second Hubble observing team, said:

This is really exciting — both because such events are super cool to watch and because they do not happen very often. Most comets that fragment are too dim to see. Events at such scale only happen once or twice a decade.

Hubble’s crisp images may yield new clues to the breakup. The telescope has distinguished pieces as small as the size of a house. Before the breakup, the entire nucleus may have been no more than the length of two football fields.

The disintegrating comet was approximately 91 million miles (146 million km) from Earth when the latest Hubble observations were taken. If any of it survives, the comet will make its closest approach to Earth on May 23 at a distance of about 72 million miles (116 million km), and eight days later it will skirt past the sun at 25 million miles (40 million km).

Bottom line: New Hubble images show comet ATLAS breaking up.

Via ESA

from EarthSky https://ift.tt/2Ska8FN

COVID-19: Fighting viruses with viruses

Since the outbreak of COVID-19, many of our scientists have been using the techniques and approaches developed over decades of cancer research to understand and defeat the virus.

While beating cancer remains our priority, we will not be able to fully focus on our mission until COVID-19 is beaten. We’re catching up with some of our researchers who are turning their expertise, experience and equipment over to COVID-19.

One lab thinks that the key is to fight the virus with another virus.

The main job of our immune system is to protect the body from potential threats – including viruses and cancer. In response to this, cancer cells have evolved multiple strategies to evade the immune system – allowing them to grow into larger and larger tumours.

At Cardiff University, Dr Alan Parker’s team looks at how we can pit one threat against another and use viruses to destroy cancer cells.

Building a Trojan Horse

The idea of giving a virus to someone with cancer may sound strange. But Parker’s team believe that, with a bit of fine-tuning, viruses can be trained to focus their destructive power on cancer cells.

The lab is particularly interested in a family of family of over 50 viruses, called adenoviruses. In most people, adenoviruses cause relatively mild conditions, such as an upset stomach or a cold (depending on the type of virus).

“We’re interested in how – at a molecular level – these viruses infect healthy cells and cause disease” says Parker. “By understanding how they do that, you can start to re-engineer the virus so it can hunt and destroy cancer cells.”

At its simplest, a virus is a bundle of genetic information wrapped up in an incredibly tiny shell. This protective coating is made up of proteins that allow the virus to interact with cells, infect them and then hijack the cell to create more of itself.

Through genetic engineering, Parker and his team modify the adenovirus DNA so that when the virus infects tumour cells, it makes them release antigens (proteins that the immune system uses to recognise and respond to threats) that are unique to the tumour.

This release teaches the immune system to be better able to target tumour cells and so – like a trojan horse – the cells inadvertantly cause their own destruction.

A battle of two viruses

It’s a technique the lab has been perfecting for several years, but their work was brought to a temporary halt by the COVID-19 outbreak.

The COVID-19 pandemic has forced universities to partially close, and a lot of Parker’s lab work had to be shut down.

Like many other scientists working at home, they wondered how they could use their skills to aid research into the virus.

After receiving a phone call from a colleague who wanted to develop tests to determine if people infected with COVID-19 had developed neutralising antibodies, Parker had a realisation – the technique his lab uses to help the immune system recognise cancer cells could also be used to train the immune system to recognise and destroy the COVID-19 virus.

“I was saying to the group, you know what might be more useful is if we engineer the adenovirus to express coronavirus antigens and use it like a vaccine.”

“It was a question of ‘who in the team was able to be sent in’ and ‘who was best placed to do the research’.”

Instead of being limited to tumour cells, the group are modifying adenovirus to enter as many cells as possible, using them as miniature factories to pump out coronavirus antigens.

This gives the immune system a chance to learn about what it can expect so when an actual COVID-19 infection occurs, the immune system is primed to deal with it.

While many labs around the world use adenoviruses as the basis for vaccines, Parker’s lab has one key advantage: freezers packed full of hundreds of adenoviruses, all subtly different.

This meant they could go back to some of the adenoviruses that they had discarded in the past as not being useful for targeting cancer and examine them in a new light.

“We know we’ve got adenoviruses that are good at what they do. Instead of expressing a cancer antigens to help the immune system recognise and kill cancer cells, we’re just going to change the tumour antigen for a viral antigen and try and make the body recognise and eliminate coronavirus when it enters the body.”

“Mouse is a very limited model…you can’t give mice [COVID-19] and see if the vaccine is protective because [COVID-19] doesn’t infect mice.”

“We think – based on timelines of other things we’ve produced – it will take us around two months to be able to produce our first batches of research grade vaccines for evaluation.”

It’s an exciting timeframe, but for a lab whittled down to just 4 researchers, this is just the start of the process of developing any kind of usable vaccine.

One of the pivotal moments will be injecting mice with their modified adenoviruses and seeing if the immune system can respond in a way that indicates it’s primed to fight off the COVID-19 virus. But there’s one big issue – mice can’t be infected by COVID-19. This means the team can’t test out whether the immune responses developed in mice will actually protect against the virus. Parker knows that the next step requires even more collaboration.

“I feel my role here is to make the tools and do what we can reasonably do in the in the fastest time possible, and then hand it over to the experts,” says Parker.

Coming back to cancer

“Cancer immunotherapies have spun out of basic and fundamental findings in immunology, and often the immunology of infectious diseases. So actually the two things are very much intertwined.”

Although they might seem like two separate worlds, Parker think that this work into COVID-19 will allow them to get a better understanding of their own research and how adenoviruses can be optimised as treatments for cancer.

“We will take that knowledge into the cancer setting to look at how the body can respond when you provide a tumour antigen in the same way, and how it can then mount an anti-cancer response. So it all kind of feeds together – at least in my head, it does.”

Alex

from Cancer Research UK – Science blog https://ift.tt/2KMmz92

Since the outbreak of COVID-19, many of our scientists have been using the techniques and approaches developed over decades of cancer research to understand and defeat the virus.

While beating cancer remains our priority, we will not be able to fully focus on our mission until COVID-19 is beaten. We’re catching up with some of our researchers who are turning their expertise, experience and equipment over to COVID-19.

One lab thinks that the key is to fight the virus with another virus.

The main job of our immune system is to protect the body from potential threats – including viruses and cancer. In response to this, cancer cells have evolved multiple strategies to evade the immune system – allowing them to grow into larger and larger tumours.

At Cardiff University, Dr Alan Parker’s team looks at how we can pit one threat against another and use viruses to destroy cancer cells.

Building a Trojan Horse

The idea of giving a virus to someone with cancer may sound strange. But Parker’s team believe that, with a bit of fine-tuning, viruses can be trained to focus their destructive power on cancer cells.

The lab is particularly interested in a family of family of over 50 viruses, called adenoviruses. In most people, adenoviruses cause relatively mild conditions, such as an upset stomach or a cold (depending on the type of virus).

“We’re interested in how – at a molecular level – these viruses infect healthy cells and cause disease” says Parker. “By understanding how they do that, you can start to re-engineer the virus so it can hunt and destroy cancer cells.”

At its simplest, a virus is a bundle of genetic information wrapped up in an incredibly tiny shell. This protective coating is made up of proteins that allow the virus to interact with cells, infect them and then hijack the cell to create more of itself.

Through genetic engineering, Parker and his team modify the adenovirus DNA so that when the virus infects tumour cells, it makes them release antigens (proteins that the immune system uses to recognise and respond to threats) that are unique to the tumour.

This release teaches the immune system to be better able to target tumour cells and so – like a trojan horse – the cells inadvertantly cause their own destruction.

A battle of two viruses

It’s a technique the lab has been perfecting for several years, but their work was brought to a temporary halt by the COVID-19 outbreak.

The COVID-19 pandemic has forced universities to partially close, and a lot of Parker’s lab work had to be shut down.

Like many other scientists working at home, they wondered how they could use their skills to aid research into the virus.

After receiving a phone call from a colleague who wanted to develop tests to determine if people infected with COVID-19 had developed neutralising antibodies, Parker had a realisation – the technique his lab uses to help the immune system recognise cancer cells could also be used to train the immune system to recognise and destroy the COVID-19 virus.

“I was saying to the group, you know what might be more useful is if we engineer the adenovirus to express coronavirus antigens and use it like a vaccine.”

“It was a question of ‘who in the team was able to be sent in’ and ‘who was best placed to do the research’.”

Instead of being limited to tumour cells, the group are modifying adenovirus to enter as many cells as possible, using them as miniature factories to pump out coronavirus antigens.

This gives the immune system a chance to learn about what it can expect so when an actual COVID-19 infection occurs, the immune system is primed to deal with it.

While many labs around the world use adenoviruses as the basis for vaccines, Parker’s lab has one key advantage: freezers packed full of hundreds of adenoviruses, all subtly different.

This meant they could go back to some of the adenoviruses that they had discarded in the past as not being useful for targeting cancer and examine them in a new light.

“We know we’ve got adenoviruses that are good at what they do. Instead of expressing a cancer antigens to help the immune system recognise and kill cancer cells, we’re just going to change the tumour antigen for a viral antigen and try and make the body recognise and eliminate coronavirus when it enters the body.”

“Mouse is a very limited model…you can’t give mice [COVID-19] and see if the vaccine is protective because [COVID-19] doesn’t infect mice.”

“We think – based on timelines of other things we’ve produced – it will take us around two months to be able to produce our first batches of research grade vaccines for evaluation.”

It’s an exciting timeframe, but for a lab whittled down to just 4 researchers, this is just the start of the process of developing any kind of usable vaccine.

One of the pivotal moments will be injecting mice with their modified adenoviruses and seeing if the immune system can respond in a way that indicates it’s primed to fight off the COVID-19 virus. But there’s one big issue – mice can’t be infected by COVID-19. This means the team can’t test out whether the immune responses developed in mice will actually protect against the virus. Parker knows that the next step requires even more collaboration.

“I feel my role here is to make the tools and do what we can reasonably do in the in the fastest time possible, and then hand it over to the experts,” says Parker.

Coming back to cancer

“Cancer immunotherapies have spun out of basic and fundamental findings in immunology, and often the immunology of infectious diseases. So actually the two things are very much intertwined.”

Although they might seem like two separate worlds, Parker think that this work into COVID-19 will allow them to get a better understanding of their own research and how adenoviruses can be optimised as treatments for cancer.

“We will take that knowledge into the cancer setting to look at how the body can respond when you provide a tumour antigen in the same way, and how it can then mount an anti-cancer response. So it all kind of feeds together – at least in my head, it does.”

Alex

from Cancer Research UK – Science blog https://ift.tt/2KMmz92