How unique is Earth?

Artist’s concept of Kepler-69f, a small rocky world that may have water. The new study suggests that many small rocky planets like this are probably quite similar to Earth or Mars in their composition. Image Via NASA/The Verge.

Assuming that all worlds in space are unique in some way … just how unique is Earth? Are there other planets out there with similar compositions, oceans, maybe even living things? We still don’t know for sure, although a quickly-growing number of rocky exoplanets at least similar in size to Earth are being discovered. But now, a new study of white dwarf stars by researchers from the University of California, Los Angeles (UCLA) provides fresh evidence that planets like Earth are probably quite common in our galaxy, an exciting implication.

The peer-reviewed study, published on October 18, 2019, in the journal Science, suggests there are many rocky planets with similar geochemistry as Earth. Various telescopes were used, primarily the W.M. Keck Observatory in Hawaii.

According to Edward Young, a UCLA professor of geochemistry and cosmochemistry:

We have just raised the probability that many rocky planets are like the Earth, and there’s a very large number of rocky planets in the universe. We’re studying geochemistry in rocks from other stars, which is almost unheard of.

As Hilke Schlichting, a UCLA associate professor of astrophysics and planetary science, explained, determining the composition of rocky material so far away is not an easy task:

Learning the composition of planets outside our solar system is very difficult. We used the only method possible – a method we pioneered – to determine the geochemistry of rocks outside of the solar system.

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

Artist’s concept of a white dwarf star with a debris disk and small planets. The new study suggests that many small rocky planets like this are probably quite similar to Earth or Mars in their composition. Image via Mark Garlick/UCLA.

The results suggest that many rocky planets likely have an oxidation rate – oxygen fugacity – similar to that of Earth or Mars. From the abstract:

Oxygen fugacity is a measure of rock oxidation that influences planetary structure and evolution. Most rocky bodies in the solar system formed at oxygen fugacities approximately five orders of magnitude higher than a hydrogen-rich gas of solar composition. It is unclear whether this oxidation of rocks in the solar system is typical among other planetary systems. We exploit the elemental abundances observed in six white dwarfs polluted by the accretion of rocky bodies to determine the fraction of oxidized iron in those extrasolar rocky bodies and therefore their oxygen fugacities. The results are consistent with the oxygen fugacities of Earth, Mars, and typical asteroids in the solar system, suggesting that at least some rocky exoplanets are geophysically and geochemically similar to Earth.

The researchers developed a unique method for analyzing the geochemistry of such worlds, without looking at the planets themselves. Instead, they studied the rocky debris left over from planets that were destroyed around white dwarf stars. They have analyzed the debris from six white dwarfs so far, and the results were intriguing. The closest white dwarf star studied is about 200 light-years from Earth and the farthest is 665 light-years away.

White dwarf stars are very small, about the same size as Earth, but much, much denser. They are the hot remaining cores of sun-like stars that have burned out. Scientists have found that rocky debris from former planets around some white dwarfs is very similar in composition to rocks from Earth and Mars. Image via ESA.

Normally, just hydrogen and helium would be found in a white dwarf star, but instead the researchers also found silicon, magnesium, carbon and oxygen. Such elements would come from rocky planets that used to orbit the stars. As Alexandra Doyle, a graduate student at UCLA who led the new study, explained:

If I were to just look at a white dwarf star, I would expect to see hydrogen and helium. But in these data, I also see other materials, such as silicon, magnesium, carbon and oxygen – material that accreted onto the white dwarfs from bodies that were orbiting them.

By observing these white dwarfs and the elements present in their atmosphere, we are observing the elements that are in the body that orbited the white dwarf. Observing a white dwarf is like doing an autopsy on the contents of what it has gobbled in its solar system.

Rocks in our solar system – from Earth, Mars and elsewhere – are similar in composition, with a lot of oxidized iron. The iron in the rocky material around the white dwarfs had been oxidized in a similar manner, according to Young:

We measured the amount of iron that got oxidized in these rocks that hit the white dwarf. Oxygen steals electrons from iron, producing iron oxide rather than iron metal. We measured the amount of iron that got oxidized in these rocks that hit the white dwarf. We studied how much the metal rusts.

All the chemistry that happens on the surface of the Earth can ultimately be traced back to the oxidation state of the planet. The fact that we have oceans and all the ingredients necessary for life can be traced back to the planet being oxidized as it is. The rocks control the chemistry.

A gray rock on Earth from Yosemite National Park, California that has experienced oxidization. Evidence for similar oxidization has been found in rocky debris around white dwarf stars, from former planets that were similar in composition to Earth or Mars. Image via Clippix ETC.

So just how similar is the rocky debris around the white dwarfs to that of planets like Earth and Mars? Very, according to Doyle:

Very similar. They are Earth-like and Mars-like in terms of their oxidized iron. We’re finding that rocks are rocks everywhere, with very similar geophysics and geochemistry.

As Young also noted:

It’s always been a mystery why the rocks in our solar system are so oxidized. It’s not what you expect. A question was whether this would also be true around other stars. Our study says yes. That bodes really well for looking for Earth-like planets in the universe.

The evidence for oxidation in the rocky debris around the white dwarfs is tantalizing, since it points to similar geological processes on the planets that used to exist. As Schlichting said:

If extraterrestrial rocks have a similar quantity of oxidation as the Earth has, then you can conclude the planet has similar plate tectonics and similar potential for magnetic fields as the Earth, which are widely believed to be key ingredients for life. This study is a leap forward in being able to make these inferences for bodies outside our own solar system and indicates it’s very likely there are truly Earth analogs.

Alexandra Doyle, a graduate student at UCLA, who led the new study. Image via UCLA.

As Doyle added:

We can determine the geochemistry of these rocks mathematically and compare these calculations with rocks that we do have from Earth and Mars. Understanding the rocks is crucial because they reveal the geochemistry and geophysics of the planet.

This new study not only provides fascinating new details on how Earth-like planets may be quite common, it is also a great example of astrophysicists and geochemists working together, according to Young:

The result is we are doing real geochemistry on rocks from outside our solar system. Most astrophysicists wouldn’t think to do this, and most geochemists wouldn’t think to ever apply this to a white dwarf.

Bottom line: A new study from UCLA suggests that there are probably many rocky worlds in our galaxy that are similar in composition and geochemistry to Earth or Mars.

Source: Oxygen fugacities of extrasolar rocks: Evidence for an Earth-like geochemistry of exoplanets

Via UCLA

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

Artist’s concept of Kepler-69f, a small rocky world that may have water. The new study suggests that many small rocky planets like this are probably quite similar to Earth or Mars in their composition. Image Via NASA/The Verge.

Assuming that all worlds in space are unique in some way … just how unique is Earth? Are there other planets out there with similar compositions, oceans, maybe even living things? We still don’t know for sure, although a quickly-growing number of rocky exoplanets at least similar in size to Earth are being discovered. But now, a new study of white dwarf stars by researchers from the University of California, Los Angeles (UCLA) provides fresh evidence that planets like Earth are probably quite common in our galaxy, an exciting implication.

The peer-reviewed study, published on October 18, 2019, in the journal Science, suggests there are many rocky planets with similar geochemistry as Earth. Various telescopes were used, primarily the W.M. Keck Observatory in Hawaii.

According to Edward Young, a UCLA professor of geochemistry and cosmochemistry:

We have just raised the probability that many rocky planets are like the Earth, and there’s a very large number of rocky planets in the universe. We’re studying geochemistry in rocks from other stars, which is almost unheard of.

As Hilke Schlichting, a UCLA associate professor of astrophysics and planetary science, explained, determining the composition of rocky material so far away is not an easy task:

Learning the composition of planets outside our solar system is very difficult. We used the only method possible – a method we pioneered – to determine the geochemistry of rocks outside of the solar system.

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

Artist’s concept of a white dwarf star with a debris disk and small planets. The new study suggests that many small rocky planets like this are probably quite similar to Earth or Mars in their composition. Image via Mark Garlick/UCLA.

The results suggest that many rocky planets likely have an oxidation rate – oxygen fugacity – similar to that of Earth or Mars. From the abstract:

Oxygen fugacity is a measure of rock oxidation that influences planetary structure and evolution. Most rocky bodies in the solar system formed at oxygen fugacities approximately five orders of magnitude higher than a hydrogen-rich gas of solar composition. It is unclear whether this oxidation of rocks in the solar system is typical among other planetary systems. We exploit the elemental abundances observed in six white dwarfs polluted by the accretion of rocky bodies to determine the fraction of oxidized iron in those extrasolar rocky bodies and therefore their oxygen fugacities. The results are consistent with the oxygen fugacities of Earth, Mars, and typical asteroids in the solar system, suggesting that at least some rocky exoplanets are geophysically and geochemically similar to Earth.

The researchers developed a unique method for analyzing the geochemistry of such worlds, without looking at the planets themselves. Instead, they studied the rocky debris left over from planets that were destroyed around white dwarf stars. They have analyzed the debris from six white dwarfs so far, and the results were intriguing. The closest white dwarf star studied is about 200 light-years from Earth and the farthest is 665 light-years away.

White dwarf stars are very small, about the same size as Earth, but much, much denser. They are the hot remaining cores of sun-like stars that have burned out. Scientists have found that rocky debris from former planets around some white dwarfs is very similar in composition to rocks from Earth and Mars. Image via ESA.

Normally, just hydrogen and helium would be found in a white dwarf star, but instead the researchers also found silicon, magnesium, carbon and oxygen. Such elements would come from rocky planets that used to orbit the stars. As Alexandra Doyle, a graduate student at UCLA who led the new study, explained:

If I were to just look at a white dwarf star, I would expect to see hydrogen and helium. But in these data, I also see other materials, such as silicon, magnesium, carbon and oxygen – material that accreted onto the white dwarfs from bodies that were orbiting them.

By observing these white dwarfs and the elements present in their atmosphere, we are observing the elements that are in the body that orbited the white dwarf. Observing a white dwarf is like doing an autopsy on the contents of what it has gobbled in its solar system.

Rocks in our solar system – from Earth, Mars and elsewhere – are similar in composition, with a lot of oxidized iron. The iron in the rocky material around the white dwarfs had been oxidized in a similar manner, according to Young:

We measured the amount of iron that got oxidized in these rocks that hit the white dwarf. Oxygen steals electrons from iron, producing iron oxide rather than iron metal. We measured the amount of iron that got oxidized in these rocks that hit the white dwarf. We studied how much the metal rusts.

All the chemistry that happens on the surface of the Earth can ultimately be traced back to the oxidation state of the planet. The fact that we have oceans and all the ingredients necessary for life can be traced back to the planet being oxidized as it is. The rocks control the chemistry.

A gray rock on Earth from Yosemite National Park, California that has experienced oxidization. Evidence for similar oxidization has been found in rocky debris around white dwarf stars, from former planets that were similar in composition to Earth or Mars. Image via Clippix ETC.

So just how similar is the rocky debris around the white dwarfs to that of planets like Earth and Mars? Very, according to Doyle:

Very similar. They are Earth-like and Mars-like in terms of their oxidized iron. We’re finding that rocks are rocks everywhere, with very similar geophysics and geochemistry.

As Young also noted:

It’s always been a mystery why the rocks in our solar system are so oxidized. It’s not what you expect. A question was whether this would also be true around other stars. Our study says yes. That bodes really well for looking for Earth-like planets in the universe.

The evidence for oxidation in the rocky debris around the white dwarfs is tantalizing, since it points to similar geological processes on the planets that used to exist. As Schlichting said:

If extraterrestrial rocks have a similar quantity of oxidation as the Earth has, then you can conclude the planet has similar plate tectonics and similar potential for magnetic fields as the Earth, which are widely believed to be key ingredients for life. This study is a leap forward in being able to make these inferences for bodies outside our own solar system and indicates it’s very likely there are truly Earth analogs.

Alexandra Doyle, a graduate student at UCLA, who led the new study. Image via UCLA.

As Doyle added:

We can determine the geochemistry of these rocks mathematically and compare these calculations with rocks that we do have from Earth and Mars. Understanding the rocks is crucial because they reveal the geochemistry and geophysics of the planet.

This new study not only provides fascinating new details on how Earth-like planets may be quite common, it is also a great example of astrophysicists and geochemists working together, according to Young:

The result is we are doing real geochemistry on rocks from outside our solar system. Most astrophysicists wouldn’t think to do this, and most geochemists wouldn’t think to ever apply this to a white dwarf.

Bottom line: A new study from UCLA suggests that there are probably many rocky worlds in our galaxy that are similar in composition and geochemistry to Earth or Mars.

Source: Oxygen fugacities of extrasolar rocks: Evidence for an Earth-like geochemistry of exoplanets

Via UCLA

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

Why don’t evergreen trees change color and drop their leaves?

What’s happening with the trees that stay green? Image via BingHao/Shutterstock.com.

By Barry Logan, Bowdoin College

It’s autumn in the Northern Hemisphere – otherwise known as leaf-peeping season. Now is when people head outside to soak up the annual display of orange, red and yellow foliage painted across the landscape.

But mixed among those bright, colorful patches are some trees that stay steadfastly green. Why do evergreen conifers sit out this blazing seasonal spectacle?

Like so many other challenges, the problem of winter can be solved by trees in more than one way.

As temperatures begin to dip, broad-leafed temperate trees – think maples and oaks – withdraw the green chlorophyll from their leaves. That’s the pigment that absorbs sunlight to power photosynthesis. Trees store the hard-won minerals, chiefly nitrogen, they’ve invested in chlorophyll in their wood for reuse in a future growing season. Yellows and oranges and reds are left fleetingly visible before the leaves drop for winter.

Evergreen conifers – cone-bearing trees – retain their foliage year-round and have a different strategy for withstanding winter’s stresses.

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Green starts to stand out in the fall woods. Image via Michele Ursi/Shutterstock.com.

Return on investment in leaves

Staying evergreen is not about continuing to conduct photosynthesis throughout the winter. Cold temperatures affect conifers’ metabolism just as they do any other organism’s. In fact, on cold wintry days, evergreen conifers perform no more photosynthesis than their leafless neighbors.

The best way to understand the benefit of evergreenness is by considering the construction costs of leaves. Needles are really just modified leaves, after all. How do trees balance the energy it takes to grow a leaf with the energy that leaf produces via photosynthesis? In other words, how long do the leaves take to repay their construction costs and offer the tree a return on its investment?

Deciduous trees must recoup their investment in their leafy canopy in only a single growing season. In contrast, evergreen conifers, by hanging onto their needles, grant those needles multiple growing seasons to contribute to their tree’s balance sheets. That’s the real benefit to staying green.

Evergreens’ greater leaf longevity means they can survive in environments that just don’t work for their deciduous cousins. At higher latitudes and elevations, shorter and cooler growing seasons can limit photosynthetic activity. Drought can further interfere with photosynthesis. In these harsher conditions, a year may not be long enough for a leaf to produce enough energy to pay back its growth costs to the tree.

This may explain why evergreen conifers dominate mountaintops and the boreal forests that stretch across high latitudes in Alaska, Canada and Northern Europe. Deciduous broad-leafed trees largely drop out of such habitats – conditions mean they can’t balance their accounts with respect to investments in leaves and leaves’ photosynthetic return in a single season.

White pine needles need to withstand only one winter. Image via Candia Baxter/Shutterstock.com.

Evergreen needle longevity varies widely and maps onto the degree of growing season stress. Some temperate trees common to southern New England, such as white pine, retain needles for only two growing seasons. Any individual white pine needle overwinters only once, minimally meeting the definition of evergreen.

Some conifers, such as larch, do not achieve even that, instead shedding their entire crown of needles each autumn in a luminously golden display that can be a highlight of the autumn foliage splendor where they are found.

In contrast, bristlecone pines, inhabitants of high elevations in the arid Southwest, hang onto individual needles for almost 50 years. It may take nearly that long for bristlecone pine needles to achieve a photosynthetic return on the investment in their construction, given the growing-season stresses they confront.

Tough bristlecone pine needles last for decades in their harsh habitat. Image via Darren J. Bradley/Shutterstock.com.

Adapting to deal with winter stresses

Overwintering is profoundly stressful for trees.

Subzero temperatures bring the risk of cellular freezing in evergreen needles – which would be lethal. To prevent freezing, evergreen conifers accumulate high concentrations of dissolved substances known as cryoprotectants that lower the freezing point of water in their cells and protect key cell structures, while not interfering with metabolism.

Cold, snow and blowing ice, along with the demands of longevity, lead evergreen conifers to invest their energy in the toughness of needles. Conifer needles vary in toughness; for instance, relatively short-lived white pine needles are more delicate. The fibrous materials that make needles more durable further deepen coniferous trees’ investment, extending the period required to achieve a return on needle construction costs.

Heavy loads of snow can result in broken branches, a prevailing risk of evergreenness. Thin, often drooping conifer needles catch less snow than the broad leaves of deciduous trees. Indeed, when deciduous trees lose branches to snowstorms, it is generally during storms on the edges of the snow season – in autumn or spring – not midwinter storms, when the crowns are leafless. If you’ve ever wondered why deciduous trees are taking so long in spring to leaf out, missing out on some excellent growing days as a result, keep in mind that trees don’t want to risk the damage that could result from a freak spring storm.

Evergreen branches are built to let snow slide off them so they don’t snap under the weight. Image via Melinda Nagy/Shutterstock.com

Conifer branch architecture is also adapted to shedding snow. Conifer branches generally sweep outwards and downwards from the trunk: Think of a Christmas fir. Not only that, conifer branches are generally more flexible than their counterparts on deciduous trees. Collecting heavy snow weighs down conifer branches until they reach an angle where it sloughs off.

No matter the species, at midlatitudes, where the snow flies in winter and growing seasons are generally mild and favorable, trees need strategies to make it through. Some recreate a crown of leaves each spring. Evergreens equip their needles and branches with features necessary to survive winter and thus live to see another spring – and, for some, many springs thereafter.

Barry Logan, Professor of Biology, Bowdoin College

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

Bottom line: Why evergreen trees don’t change color or drop their leaves in the fall.

from EarthSky https://ift.tt/2N6loDG

What’s happening with the trees that stay green? Image via BingHao/Shutterstock.com.

By Barry Logan, Bowdoin College

It’s autumn in the Northern Hemisphere – otherwise known as leaf-peeping season. Now is when people head outside to soak up the annual display of orange, red and yellow foliage painted across the landscape.

But mixed among those bright, colorful patches are some trees that stay steadfastly green. Why do evergreen conifers sit out this blazing seasonal spectacle?

Like so many other challenges, the problem of winter can be solved by trees in more than one way.

As temperatures begin to dip, broad-leafed temperate trees – think maples and oaks – withdraw the green chlorophyll from their leaves. That’s the pigment that absorbs sunlight to power photosynthesis. Trees store the hard-won minerals, chiefly nitrogen, they’ve invested in chlorophyll in their wood for reuse in a future growing season. Yellows and oranges and reds are left fleetingly visible before the leaves drop for winter.

Evergreen conifers – cone-bearing trees – retain their foliage year-round and have a different strategy for withstanding winter’s stresses.

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

Green starts to stand out in the fall woods. Image via Michele Ursi/Shutterstock.com.

Return on investment in leaves

Staying evergreen is not about continuing to conduct photosynthesis throughout the winter. Cold temperatures affect conifers’ metabolism just as they do any other organism’s. In fact, on cold wintry days, evergreen conifers perform no more photosynthesis than their leafless neighbors.

The best way to understand the benefit of evergreenness is by considering the construction costs of leaves. Needles are really just modified leaves, after all. How do trees balance the energy it takes to grow a leaf with the energy that leaf produces via photosynthesis? In other words, how long do the leaves take to repay their construction costs and offer the tree a return on its investment?

Deciduous trees must recoup their investment in their leafy canopy in only a single growing season. In contrast, evergreen conifers, by hanging onto their needles, grant those needles multiple growing seasons to contribute to their tree’s balance sheets. That’s the real benefit to staying green.

Evergreens’ greater leaf longevity means they can survive in environments that just don’t work for their deciduous cousins. At higher latitudes and elevations, shorter and cooler growing seasons can limit photosynthetic activity. Drought can further interfere with photosynthesis. In these harsher conditions, a year may not be long enough for a leaf to produce enough energy to pay back its growth costs to the tree.

This may explain why evergreen conifers dominate mountaintops and the boreal forests that stretch across high latitudes in Alaska, Canada and Northern Europe. Deciduous broad-leafed trees largely drop out of such habitats – conditions mean they can’t balance their accounts with respect to investments in leaves and leaves’ photosynthetic return in a single season.

White pine needles need to withstand only one winter. Image via Candia Baxter/Shutterstock.com.

Evergreen needle longevity varies widely and maps onto the degree of growing season stress. Some temperate trees common to southern New England, such as white pine, retain needles for only two growing seasons. Any individual white pine needle overwinters only once, minimally meeting the definition of evergreen.

Some conifers, such as larch, do not achieve even that, instead shedding their entire crown of needles each autumn in a luminously golden display that can be a highlight of the autumn foliage splendor where they are found.

In contrast, bristlecone pines, inhabitants of high elevations in the arid Southwest, hang onto individual needles for almost 50 years. It may take nearly that long for bristlecone pine needles to achieve a photosynthetic return on the investment in their construction, given the growing-season stresses they confront.

Tough bristlecone pine needles last for decades in their harsh habitat. Image via Darren J. Bradley/Shutterstock.com.

Adapting to deal with winter stresses

Overwintering is profoundly stressful for trees.

Subzero temperatures bring the risk of cellular freezing in evergreen needles – which would be lethal. To prevent freezing, evergreen conifers accumulate high concentrations of dissolved substances known as cryoprotectants that lower the freezing point of water in their cells and protect key cell structures, while not interfering with metabolism.

Cold, snow and blowing ice, along with the demands of longevity, lead evergreen conifers to invest their energy in the toughness of needles. Conifer needles vary in toughness; for instance, relatively short-lived white pine needles are more delicate. The fibrous materials that make needles more durable further deepen coniferous trees’ investment, extending the period required to achieve a return on needle construction costs.

Heavy loads of snow can result in broken branches, a prevailing risk of evergreenness. Thin, often drooping conifer needles catch less snow than the broad leaves of deciduous trees. Indeed, when deciduous trees lose branches to snowstorms, it is generally during storms on the edges of the snow season – in autumn or spring – not midwinter storms, when the crowns are leafless. If you’ve ever wondered why deciduous trees are taking so long in spring to leaf out, missing out on some excellent growing days as a result, keep in mind that trees don’t want to risk the damage that could result from a freak spring storm.

Evergreen branches are built to let snow slide off them so they don’t snap under the weight. Image via Melinda Nagy/Shutterstock.com

Conifer branch architecture is also adapted to shedding snow. Conifer branches generally sweep outwards and downwards from the trunk: Think of a Christmas fir. Not only that, conifer branches are generally more flexible than their counterparts on deciduous trees. Collecting heavy snow weighs down conifer branches until they reach an angle where it sloughs off.

No matter the species, at midlatitudes, where the snow flies in winter and growing seasons are generally mild and favorable, trees need strategies to make it through. Some recreate a crown of leaves each spring. Evergreens equip their needles and branches with features necessary to survive winter and thus live to see another spring – and, for some, many springs thereafter.

Barry Logan, Professor of Biology, Bowdoin College

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

Bottom line: Why evergreen trees don’t change color or drop their leaves in the fall.

from EarthSky https://ift.tt/2N6loDG

All you need to know: Taurid meteors

Taurid fireball through light clouds – November 1, 2018 – by Eliot Herman in Tucson, Arizona. Notice the moon, just rising, on the left.

The South and North Taurid meteor showers aren’t known for their large numbers of meteors, but they do offer a high percentage of fireballs, or exceptionally bright meteors. This shower made a huge splash four years ago, in 2015, when there were many, many reports and photos featuring Taurid fireball sightings. Higher rates of Taurid fireballs appear to happen in seven-year cycles. Grand fireball displays did indeed take place in 2008 and 2015. No elevated levels of fireballs are expected in 2019. Even so, watch out for Taurid meteors – and possible fireballs – throughout November.

The nominal peak night for the South Taurids is November 6 while that of the North Taurids is about a week later, on November 12 (the same date as the November 2019 full moon). So this year, in 2019, the first several days of November may be best for watching the Taurids, as there will be no to little moon to disrupt the show. But you might even see a Taurid or two on the night of the full moon, given the high percentage of fireballs accompanying the Taurids.

Taurid fireball on the evening of October 21, 2017 – 10:27 p.m. – from Joanne West at Gold Canyon, Arizona. Eliot Herman in Tucson caught this same meteor. Read more about the 2 photos.

The prime time viewing hours are from late night until dawn, with the peak viewing coming just after the midnight hour. In general, the South Taurids offer about five meteors per hour at their peak, but the North Taurid shower may add a few more meteors to the mix. How many you’ll see will depend on how far from city lights you are … and how bright the meteors are. If they’re bright enough, they’ll overcome skies beset by light pollution.

Taurid meteors radiate from the constellation Taurus, but they’ll appear in all parts of the sky.

The Taurid meteor stream consists of an extremely wide roadway of far-flung debris left behind by Comet 2P/Encke. When Earth travels through this belt of comet debris, bits and pieces of Comet 2P/Encke smash into the Earth’s upper atmosphere to vaporize as rather slow-moving Taurid meteors (28 km/17 miles per second).

Apparently, the original Taurid stream has been perturbed by Jupiter into two branches: South and North Taurids.

Comet Encke, parent of the Taurid meteor shower. Image via Messenger.

Bottom line: South and North Taurid meteors – some of them bright fireballs – can be seen through late October and November, each year.

from EarthSky https://ift.tt/2AHknf3

Taurid fireball through light clouds – November 1, 2018 – by Eliot Herman in Tucson, Arizona. Notice the moon, just rising, on the left.

The South and North Taurid meteor showers aren’t known for their large numbers of meteors, but they do offer a high percentage of fireballs, or exceptionally bright meteors. This shower made a huge splash four years ago, in 2015, when there were many, many reports and photos featuring Taurid fireball sightings. Higher rates of Taurid fireballs appear to happen in seven-year cycles. Grand fireball displays did indeed take place in 2008 and 2015. No elevated levels of fireballs are expected in 2019. Even so, watch out for Taurid meteors – and possible fireballs – throughout November.

The nominal peak night for the South Taurids is November 6 while that of the North Taurids is about a week later, on November 12 (the same date as the November 2019 full moon). So this year, in 2019, the first several days of November may be best for watching the Taurids, as there will be no to little moon to disrupt the show. But you might even see a Taurid or two on the night of the full moon, given the high percentage of fireballs accompanying the Taurids.

Taurid fireball on the evening of October 21, 2017 – 10:27 p.m. – from Joanne West at Gold Canyon, Arizona. Eliot Herman in Tucson caught this same meteor. Read more about the 2 photos.

The prime time viewing hours are from late night until dawn, with the peak viewing coming just after the midnight hour. In general, the South Taurids offer about five meteors per hour at their peak, but the North Taurid shower may add a few more meteors to the mix. How many you’ll see will depend on how far from city lights you are … and how bright the meteors are. If they’re bright enough, they’ll overcome skies beset by light pollution.

Taurid meteors radiate from the constellation Taurus, but they’ll appear in all parts of the sky.

The Taurid meteor stream consists of an extremely wide roadway of far-flung debris left behind by Comet 2P/Encke. When Earth travels through this belt of comet debris, bits and pieces of Comet 2P/Encke smash into the Earth’s upper atmosphere to vaporize as rather slow-moving Taurid meteors (28 km/17 miles per second).

Apparently, the original Taurid stream has been perturbed by Jupiter into two branches: South and North Taurids.

Comet Encke, parent of the Taurid meteor shower. Image via Messenger.

Bottom line: South and North Taurid meteors – some of them bright fireballs – can be seen through late October and November, each year.

from EarthSky https://ift.tt/2AHknf3

Is daylight time worth the trouble?

Falling back or staying put? Image via Romolo Tavani/Shutterstock.com.

By Laura Grant, Claremont McKenna College

This weekend, public service announcements will remind us to “fall back,” ending daylight saving time by setting our clocks an hour earlier on Sunday, November 3. On November 4, many of us will commute home in the dark.

This semiannual ritual shifts our rhythms and temporarily makes us groggy at times when we normally feel alert. Moreover, many Americans are confused about why we spring forward in March and fall back in November, and whether it is worth the trouble.

The practice of resetting clocks is not designed for farmers, whose plows follow the sun regardless of what time clocks say it is. And it does not create extra daylight – it simply shifts when the sun rises and sets relative to society’s regular schedule and routines.

The key question is how people respond to this enforced shift. Most people have to be at work at a certain time – say, 8:30 a.m. – and if that time comes an hour earlier, they simply get up an hour earlier. The effect on society is another question. Here, the research shows that daylight saving time is more burden than boon.

No energy savings

Benjamin Franklin was one of the first thinkers to endorse the idea of making better use of daylight. Although he lived well before the invention of light bulbs, Franklin observed that people who slept past sunrise wasted more candles later in the evening. He also whimsically suggested the first policy fixes to encourage energy conservation: firing cannons at dawn as public alarm clocks, and fining homeowners who put up window shutters.

To this day, our laws equate daylight saving with energy conservation. However, recent research suggests that it actually increases energy use.

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Poster celebrating enactment of daylight saving time during World War I, 1917. Image via Library of Congress/Wikipedia.

This is what I found in a study co-authored with Yale economist Matthew Kotchen. We used a policy change in Indiana to estimate daylight saving time’s effects on electricity consumption. Prior to 2006, most Indiana counties did not observe it. By comparing households’ electricity demand before and after daylight saving time was adopted, month by month, we showed that it had actually increased residential electricity demand in Indiana by 1 to 4 percent annually.

The largest effects occurred in the summer – when shifting clocks forward aligns our lives with the hottest part of the day, so that people tend to use more air conditioning – and late fall, when we wake up in a cold dark house and use more heating, with no reduction in lighting needs.

Other studies corroborate these findings. Research in Australia and in the United States shows that daylight saving time does not decrease total energy use. However, it does smooth out peaks and valleys in energy demand throughout the day, as people at home use more electricity in the morning and less during the afternoon. Though people still use more electricity, shifting the timing reduces average costs to deliver energy because not everyone demands it during typical peak usage periods.

Other outcomes are mixed

Daylight saving time proponents also argue that changing times provides more hours for afternoon recreation and reduces crime rates. The best time for recreation is a matter of preference. However, there is better evidence on crime rates: Fewer muggings and sexual assaults occur during daylight saving time months because fewer potential victims are out after dark.

Overall, net benefits from these three durational effects of crime, recreation and energy use – that is, impacts that last for the duration of the time change – are murky.

Other consequences of daylight saving time are ephemeral. I think of them as bookend effects, since they occur when we change our clocks.

When we “spring forward” in March we lose an hour, which comes disproportionately from resting hours rather than wakeful time. Therefore, many problems associated with springing forward stem from sleep deprivation. With less rest, people make more mistakes, which appear to cause more traffic accidents and workplace injuries, lower workplace productivity due to cyberloafing and poorer stock market trading.

Even when we gain that hour back in the fall, we must readjust our routines over several days because the sun and our alarm clocks feel out of synchronization, much like jet lag. Some impacts are serious: During bookend weeks, children in higher latitudes go to school in the dark, which increases the risk of pedestrian casualties. Dark commutes are so problematic for pedestrians that New York City is repeating the “Dusk and Darkness” safety campaign that it launched in 2016. And heart attacks increase after the spring time shift – it is thought because of lack of sleep – but decrease to a lesser extent after the fall shift. Collectively, these bookend effects represent net costs and strong arguments against retaining daylight saving time.

Pick your own time zone?

Spurred by many of these arguments, at least 16 states have considered changes to daylight saving time this year. Some bills would end daylight saving time, while others would make it permanent. For example, Massachusetts is studying whether to move in coordination with other New England states to Atlantic Time, joining Canada’s Maritime provinces one hour ahead of Eastern Standard Time. If they shift, travelers flying from Los Angeles to Boston would cross five time zones.

Countries observing daylight saving time (blue in Northern Hemisphere, orange in Southern Hemisphere). Light gray countries have abandoned DST; dark gray nations have never practiced it. Image via TimeZonesBoy/Wikipedia.

Some states have good reason for diverging from the norm. Notably, Hawaii does not practice daylight saving time because it is much closer to the equator than the rest of the nation, so its daylight hours barely change throughout the year. Arizona is the sole contiguous state that abstains from daylight saving time, citing its extreme summer temperatures. Although this disparity causes confusion for western travelers, the state’s residents have not changed clocks’ times for over 40 years.

In my research I have found that everyone has strong opinions about daylight saving time. Many people welcome the shift in March as a signal of spring. Others like the coordinated availability of daylight after work. Dissenters, including farmers, curse their loss of quiet morning hours.

When the evidence about costs and benefits is mixed but we need to make coordinated choices, how should we make decisions? The strongest arguments, with the exception of energy costs, support not only doing away with the switches but keeping the nation on daylight saving time year-round. This provides the benefits of after- work sun without the schedule disruptions. Yet humans adapt. If we abandon the twice-yearly switch, we may eventually slide back into old routines and habits of sleeping in during daylight. Daylight saving time is the coordinated alarm to wake us up a bit earlier in the summer and get us out of work with more sunshine.

Editor’s note: This is an updated version of an article originally published on November 2, 2016.

Laura Grant, Assistant Professor of Economics, Claremont McKenna College

This article was originally published on The Conversation. Read the original article.

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

Falling back or staying put? Image via Romolo Tavani/Shutterstock.com.

By Laura Grant, Claremont McKenna College

This weekend, public service announcements will remind us to “fall back,” ending daylight saving time by setting our clocks an hour earlier on Sunday, November 3. On November 4, many of us will commute home in the dark.

This semiannual ritual shifts our rhythms and temporarily makes us groggy at times when we normally feel alert. Moreover, many Americans are confused about why we spring forward in March and fall back in November, and whether it is worth the trouble.

The practice of resetting clocks is not designed for farmers, whose plows follow the sun regardless of what time clocks say it is. And it does not create extra daylight – it simply shifts when the sun rises and sets relative to society’s regular schedule and routines.

The key question is how people respond to this enforced shift. Most people have to be at work at a certain time – say, 8:30 a.m. – and if that time comes an hour earlier, they simply get up an hour earlier. The effect on society is another question. Here, the research shows that daylight saving time is more burden than boon.

No energy savings

Benjamin Franklin was one of the first thinkers to endorse the idea of making better use of daylight. Although he lived well before the invention of light bulbs, Franklin observed that people who slept past sunrise wasted more candles later in the evening. He also whimsically suggested the first policy fixes to encourage energy conservation: firing cannons at dawn as public alarm clocks, and fining homeowners who put up window shutters.

To this day, our laws equate daylight saving with energy conservation. However, recent research suggests that it actually increases energy use.

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Poster celebrating enactment of daylight saving time during World War I, 1917. Image via Library of Congress/Wikipedia.

This is what I found in a study co-authored with Yale economist Matthew Kotchen. We used a policy change in Indiana to estimate daylight saving time’s effects on electricity consumption. Prior to 2006, most Indiana counties did not observe it. By comparing households’ electricity demand before and after daylight saving time was adopted, month by month, we showed that it had actually increased residential electricity demand in Indiana by 1 to 4 percent annually.

The largest effects occurred in the summer – when shifting clocks forward aligns our lives with the hottest part of the day, so that people tend to use more air conditioning – and late fall, when we wake up in a cold dark house and use more heating, with no reduction in lighting needs.

Other studies corroborate these findings. Research in Australia and in the United States shows that daylight saving time does not decrease total energy use. However, it does smooth out peaks and valleys in energy demand throughout the day, as people at home use more electricity in the morning and less during the afternoon. Though people still use more electricity, shifting the timing reduces average costs to deliver energy because not everyone demands it during typical peak usage periods.

Other outcomes are mixed

Daylight saving time proponents also argue that changing times provides more hours for afternoon recreation and reduces crime rates. The best time for recreation is a matter of preference. However, there is better evidence on crime rates: Fewer muggings and sexual assaults occur during daylight saving time months because fewer potential victims are out after dark.

Overall, net benefits from these three durational effects of crime, recreation and energy use – that is, impacts that last for the duration of the time change – are murky.

Other consequences of daylight saving time are ephemeral. I think of them as bookend effects, since they occur when we change our clocks.

When we “spring forward” in March we lose an hour, which comes disproportionately from resting hours rather than wakeful time. Therefore, many problems associated with springing forward stem from sleep deprivation. With less rest, people make more mistakes, which appear to cause more traffic accidents and workplace injuries, lower workplace productivity due to cyberloafing and poorer stock market trading.

Even when we gain that hour back in the fall, we must readjust our routines over several days because the sun and our alarm clocks feel out of synchronization, much like jet lag. Some impacts are serious: During bookend weeks, children in higher latitudes go to school in the dark, which increases the risk of pedestrian casualties. Dark commutes are so problematic for pedestrians that New York City is repeating the “Dusk and Darkness” safety campaign that it launched in 2016. And heart attacks increase after the spring time shift – it is thought because of lack of sleep – but decrease to a lesser extent after the fall shift. Collectively, these bookend effects represent net costs and strong arguments against retaining daylight saving time.

Pick your own time zone?

Spurred by many of these arguments, at least 16 states have considered changes to daylight saving time this year. Some bills would end daylight saving time, while others would make it permanent. For example, Massachusetts is studying whether to move in coordination with other New England states to Atlantic Time, joining Canada’s Maritime provinces one hour ahead of Eastern Standard Time. If they shift, travelers flying from Los Angeles to Boston would cross five time zones.

Countries observing daylight saving time (blue in Northern Hemisphere, orange in Southern Hemisphere). Light gray countries have abandoned DST; dark gray nations have never practiced it. Image via TimeZonesBoy/Wikipedia.

Some states have good reason for diverging from the norm. Notably, Hawaii does not practice daylight saving time because it is much closer to the equator than the rest of the nation, so its daylight hours barely change throughout the year. Arizona is the sole contiguous state that abstains from daylight saving time, citing its extreme summer temperatures. Although this disparity causes confusion for western travelers, the state’s residents have not changed clocks’ times for over 40 years.

In my research I have found that everyone has strong opinions about daylight saving time. Many people welcome the shift in March as a signal of spring. Others like the coordinated availability of daylight after work. Dissenters, including farmers, curse their loss of quiet morning hours.

When the evidence about costs and benefits is mixed but we need to make coordinated choices, how should we make decisions? The strongest arguments, with the exception of energy costs, support not only doing away with the switches but keeping the nation on daylight saving time year-round. This provides the benefits of after- work sun without the schedule disruptions. Yet humans adapt. If we abandon the twice-yearly switch, we may eventually slide back into old routines and habits of sleeping in during daylight. Daylight saving time is the coordinated alarm to wake us up a bit earlier in the summer and get us out of work with more sunshine.

Editor’s note: This is an updated version of an article originally published on November 2, 2016.

Laura Grant, Assistant Professor of Economics, Claremont McKenna College

This article was originally published on The Conversation. Read the original article.

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

Mist over an Antarctic research station

View larger. | Twilight in Antarctica. Image via the European Space Agency.

The European Space Agency (ESA) released this image this month of a twilight mist above the Concordia Research Station, a French–Italian facility built 2 miles (3,233 meters) above sea level at a location called Dome C on the Antarctic Plateau. ESA has called this location the remotest base on Earth and explained:

The nearest human beings are stationed some 600 km [about 400 miles] away at the Russian Vostok base, making Concordia more remote than the International Space Station [about 250 miles, or 400 km, above Earth].

It’s also very cold there, of course. ESA said:

A place of extremes, temperatures can drop to –80°C in the winter, with a yearly average temperature of –50°C.

The Concordia Research Station undergoes about four months of continuous night each year. Sunlight returns in August; that’s probably when the photo above was taken. Now, ESA said, the station is getting ready for the influx of summer visitors. Linens are being washed, mattresses cleaned and changed, and fresh food supplies are arriving. Concordia hosts up to 80 researchers in the busy summer months – from around now through about February – who come to set up sensors and run experiments.

Read more via ESA: First sun come to Concordia Research Station in August

Read more via ESA: The most remote base on Earth

Read more via ESA: Antarctic mist

Location of Dome C in Antarctica.

Bottom line: As we in the Northern Hemisphere experience longer nights and shorter days, Antarctica is nearing its season of 24-hour sunlight. This photo shows a period of twilight at the Concordia Research Station in East Antarctica.

Via ESA

from EarthSky https://ift.tt/2WvMbw8

View larger. | Twilight in Antarctica. Image via the European Space Agency.

The European Space Agency (ESA) released this image this month of a twilight mist above the Concordia Research Station, a French–Italian facility built 2 miles (3,233 meters) above sea level at a location called Dome C on the Antarctic Plateau. ESA has called this location the remotest base on Earth and explained:

The nearest human beings are stationed some 600 km [about 400 miles] away at the Russian Vostok base, making Concordia more remote than the International Space Station [about 250 miles, or 400 km, above Earth].

It’s also very cold there, of course. ESA said:

A place of extremes, temperatures can drop to –80°C in the winter, with a yearly average temperature of –50°C.

The Concordia Research Station undergoes about four months of continuous night each year. Sunlight returns in August; that’s probably when the photo above was taken. Now, ESA said, the station is getting ready for the influx of summer visitors. Linens are being washed, mattresses cleaned and changed, and fresh food supplies are arriving. Concordia hosts up to 80 researchers in the busy summer months – from around now through about February – who come to set up sensors and run experiments.

Read more via ESA: First sun come to Concordia Research Station in August

Read more via ESA: The most remote base on Earth

Read more via ESA: Antarctic mist

Location of Dome C in Antarctica.

Bottom line: As we in the Northern Hemisphere experience longer nights and shorter days, Antarctica is nearing its season of 24-hour sunlight. This photo shows a period of twilight at the Concordia Research Station in East Antarctica.

Via ESA

from EarthSky https://ift.tt/2WvMbw8

Moon, Saturn, Jupiter in early November

At nightfall and early evening – November 1 and 2, 2019 – the waxing crescent moon shines in the vicinity of the planet Saturn, and the dazzling planet Jupiter sits below the moon and Saturn, fairly close to the horizon.

As the moon swings by Saturn in early November 2019, it’ll pass to the north of the ringed planet for most of the globe. However, for some far-southern latitudes, the moon will actually occult (cover over) Saturn on November 2, 2019. From New Zealand, this occultation of Saturn will take place at nightfall. (By the time that we in North America see the moon and Saturn at nightfall November 2, 2019, the moon will be well to the east of Saturn.)

We refer you to the worldwide map below via IOTA (International Occultation Timing Association), showing in which part of the world this occultation takes place. Only the part of the world in between the solid white lines can see the occultation in a nighttime sky. The swath in between the dotted red lines depicts where the occultation happens in daytime; and the area in between the short blue lines shows where the occultation occurs at evening dusk.

Only a small section of the world in between the solid white lines (New Zealand) gets to watch the occultation of Saturn at nightfall and early evening on November 2, 2019. Image via IOTA.

We give the occultation times for Auckland, New Zealand, in local New Zealand Daylight Time (NZDT):

Occultation begins (Saturn disappears behind dark side of moon): 9:17 p.m. NZDT
Occultation ends (Saturn reappears from behind moon’s lit side): 9:58 p.m NZDT

Click here if you wish to know the occultation times at other New Zealand localities, remembering to add 13 hours to change Universal Time (UTC) to local time (NZDT = UTC + 13 hours).

Saturn, the 6th planet outward from the sun, is the farthest and slowest-moving planet that we can easily see with the eye alone. Dazzling Jupiter, the 5th planet outward from the sun, is the second-slowest bright planet, after Saturn. For that reason, Jupiter/Saturn conjunctions are the rarest of bright planet conjunctions, by virtue of their slow motions in front of the constellations of the zodiac. Saturn takes nearly 30 years to go around the sun full circle whereas Jupiter takes nearly 12 years.

Johannes Kepler (1571 to 1630) maps out 10 heliocentric (sun-centered) Jupiter/Saturn conjunctions during the 180-year period from 1583 to 1763. After 60 years, the planets meet up at nearly the same place on the zodiac, with a displacement of about 8 degrees eastward relative to the background stars. Drawing taken from Kepler’s De Stella Nova (Prague, 1606).

The next grand conjunction will be forthcoming on December 21, 2020. From the years 2000 to 2100 inclusive, as viewed from our planet Earth, these Jupiter/Saturn conjunctions (in ecliptic longitude) happen on these dates:

2000 May 28
2020 Dec 21
2040 Oct 31
2060 Apr 07
2080 Mar 15
2100 Sep 18

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

In early November 2019, let the moon be your guide to the planets Saturn and Jupiter. From New Zealand, watch the moon occult Saturn at nightfall/early evening on November 2, 2019. Next year, on the December 2020 solstice, the great conjunction of Jupiter/Saturn will happen for the first time since May 28, 2000.

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

At nightfall and early evening – November 1 and 2, 2019 – the waxing crescent moon shines in the vicinity of the planet Saturn, and the dazzling planet Jupiter sits below the moon and Saturn, fairly close to the horizon.

As the moon swings by Saturn in early November 2019, it’ll pass to the north of the ringed planet for most of the globe. However, for some far-southern latitudes, the moon will actually occult (cover over) Saturn on November 2, 2019. From New Zealand, this occultation of Saturn will take place at nightfall. (By the time that we in North America see the moon and Saturn at nightfall November 2, 2019, the moon will be well to the east of Saturn.)

We refer you to the worldwide map below via IOTA (International Occultation Timing Association), showing in which part of the world this occultation takes place. Only the part of the world in between the solid white lines can see the occultation in a nighttime sky. The swath in between the dotted red lines depicts where the occultation happens in daytime; and the area in between the short blue lines shows where the occultation occurs at evening dusk.

Only a small section of the world in between the solid white lines (New Zealand) gets to watch the occultation of Saturn at nightfall and early evening on November 2, 2019. Image via IOTA.

We give the occultation times for Auckland, New Zealand, in local New Zealand Daylight Time (NZDT):

Occultation begins (Saturn disappears behind dark side of moon): 9:17 p.m. NZDT
Occultation ends (Saturn reappears from behind moon’s lit side): 9:58 p.m NZDT

Click here if you wish to know the occultation times at other New Zealand localities, remembering to add 13 hours to change Universal Time (UTC) to local time (NZDT = UTC + 13 hours).

Saturn, the 6th planet outward from the sun, is the farthest and slowest-moving planet that we can easily see with the eye alone. Dazzling Jupiter, the 5th planet outward from the sun, is the second-slowest bright planet, after Saturn. For that reason, Jupiter/Saturn conjunctions are the rarest of bright planet conjunctions, by virtue of their slow motions in front of the constellations of the zodiac. Saturn takes nearly 30 years to go around the sun full circle whereas Jupiter takes nearly 12 years.

Johannes Kepler (1571 to 1630) maps out 10 heliocentric (sun-centered) Jupiter/Saturn conjunctions during the 180-year period from 1583 to 1763. After 60 years, the planets meet up at nearly the same place on the zodiac, with a displacement of about 8 degrees eastward relative to the background stars. Drawing taken from Kepler’s De Stella Nova (Prague, 1606).

The next grand conjunction will be forthcoming on December 21, 2020. From the years 2000 to 2100 inclusive, as viewed from our planet Earth, these Jupiter/Saturn conjunctions (in ecliptic longitude) happen on these dates:

2000 May 28
2020 Dec 21
2040 Oct 31
2060 Apr 07
2080 Mar 15
2100 Sep 18

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

In early November 2019, let the moon be your guide to the planets Saturn and Jupiter. From New Zealand, watch the moon occult Saturn at nightfall/early evening on November 2, 2019. Next year, on the December 2020 solstice, the great conjunction of Jupiter/Saturn will happen for the first time since May 28, 2000.

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

November guide to the bright planets

Watch for the young crescent moon near Jupiter on October 30 and 31, and then near Saturn on November 1 and 2. Read more.

Click the name of a planet to learn more about its visibility in November 2019: Venus, Jupiter, Saturn, Mars and Mercury.

Jupiter – the second-brightest planet after Venus – adorns the western sky at dusk and nightfall. Venus lurks below Jupiter nearly all month long, until these two dazzling beauties meet up for a conjunction on November 24, 2019. By the month’s end, Venus will have moved above Jupiter in the evening sky.

Jupiter pops out at dusk – brighter than any star – and stays out until early evening at mid-northern latitudes (mid-evening at temperate latitudes in the Southern Hemisphere). Not sure which one is Jupiter? See the moon in Jupiter’s vicinity for several days, centered on or near Halloween and then again on or near November 27.

Need more confirmation? Find a bright object you think is Jupiter, steady your binoculars – maybe sit down and anchor them on your knees, or prop your elbows on a fence railing – and aim them at that very bright light. If it is Jupiter, at least one or more of its four largest moons should pop into view.

At mid-northern latitudes in the Northern Hemisphere, Jupiter appears in the southwest sky at dusk. In early November, Jupiter sets around 7 to 8 p.m. (8 to 9 p.m. daylight saving time). By the month’s end, Jupiter sets at nightfall, around 6 p.m.

At temperate latitudes in the Southern Hemisphere, the king planet stays out till around 10 p.m. in early November, and by late November, Jupiter sets at nightfall, or around 8 p.m.

Try Stellarium Online for the view from your location.

At nightfall and early evening – November 1 and 2, 2019 – the waxing crescent moon shines in the vicinity of the planet Saturn, and the dazzling planet Jupiter sits below the moon and Saturn, fairly close to the horizon. Read more.

Saturn. After you find Jupiter at dusk and nightfall, use this brilliant beauty of a planet to find another bright evening planet, Saturn. Saturn is not as bright as Jupiter, but the ringed planet shines on a par with the sky’s brightest stars. Hold your fist at arm’s length. Saturn is roughly two fist-widths to the east of (or above) Jupiter. Because Saturn is the only bright-looking “star” to occupy this part of the sky, you’re not likely to mistake a bright star for Saturn.

Read more: When Jupiter and Saturn meet

Saturn – a golden world to the eye alone – pops out at nightfall and stays out well after nightfall. This planet still shines as brightly as a 1st-magnitude star, in other words, as brightly as our sky’s brightest stars.

Viewing Saturn’s rings soon? Read me 1st

At mid-northern latitudes, Saturn plunges below the horizon around 9 p.m. (10 p.m. daylight saving time) in early November. Near the month’s end, Saturn sets around 7 to 8 p.m.

At temperate latitudes in the Southern Hemisphere, in early November, Saturn sinks below the horizon near the midnight hour. (Midnight in this usage means midway between sunset and sunrise.) By the month’s end, Saturn sets around 9 to 10 p.m.

You won’t mistake Jupiter for Saturn. Jupiter is significantly the brighter of these two worlds. The king planet Jupiter ranks as the fourth-brightest celestial object after the sun, moon and Venus, outshining Saturn by about 10 times. What’s more, at nightfall and early evening in November 2019, Jupiter shines well to the west of Saturn.

Watch for the waxing crescent moon to join up with Saturn in early November, as shown on the sky chart above, and then again at the month’s end, as shown on the sky chart below.

Watch for the young moon to fly by Jupiter, Venus and Saturn in late November 2019. By the month’s end, Venus will have climbed above Jupiter in the evening sky. Read more.

Venus – the brightest planet – climbs out of the glare of evening dusk throughout the month, becoming more prominent in the evening sky in late November. Venus starts out the month below Jupiter, the second-brightest planet after Venus. But watch for Venus to soar upward day by day while Jupiter sinks downward. These two dazzling beauties will meet up for a close-knit conjunction on November 24, 2019, as shown on the sky chart below. By the month’s end, Venus hovers over Jupiter, as she reclaims her stature as the evening “star.”

At mid-northern latitudes in early November, Venus sets about one hour after sunset; but by the month’s end, that’ll increase to nearly two hours.

At temperate latitudes in the Southern Hemisphere, Venus sets about 1 1/2 hours after the sun in early November, and some two hours after sunset by the month’s end.

Watch for the young waxing crescent moon to pair up with Venus on or near November 28, as shown on the chart above.

It should be grand viewing Venus and Jupiter in conjunction in the evening twilight on November 24, 2019. After all, Venus and Jupiter rank as the 3rd-brightest and 4th-brightest heavenly bodies, respectively, after the sun and moon. Read more.

Transit of Mercury from San Juan, Puerto Rico – May 9, 2016 – by Fernando Roquel Torres. The next transit of Mercury will take place on November 11, 2019. Read more.

Mercury shifts from the evening sky to the morning sky on November 11, 2019. Most of the time, as seen from Earth, Mercury swings to the north or south of the sun as its transitions over to the morning sky at inferior conjunction (see diagram below). But not this time! Mercury passes directly in front of the sun, to show itself as a small black dot crossing the solar disk. You need an optical aid and proper eye protection to safely watch this transit of Mercury.

Read more: Transit of Mercury on November 11, 2019

This diagram depicts an inferior conjunction of Venus or Mercury. At such times, the inner planet passes between the Earth and sun. Image via COSMOS.

From southerly latitudes, it may be possible to catch Mercury after sunset in early November; and, from northerly latitudes, to view Mercury before sunrise during the last week or two of November. Watch for the waning crescent moon to pair up with Mercury around November 24 or 25, as shown on the sky chart below.

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

Where is Mars? Sitting in the glare of morning twilight, modestly-bright Mars slowly climbs out the glare of morning twilight throughout November. Mars is more easily seen from the Northern Hemisphere and southern tropics than at temperate latitudes in the Southern Hemisphere. At mid-northern latitudes, Mars rises about two hours before the sun in early November, and by the month’s end, rises some 2 1/2 hours before.

At temperate latitudes in the Southern Hemisphere, Mars comes up about one hour before the sun in early November, and about 1 1/2 hours before sunrise at the month’s end.

Watch for the old waning crescent moon to couple up with Mars on or near November 25, as shown on the above sky chart.

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: In November 2019, a line-up three planets – Saturn, Jupiter and Venus – adorns the sky at dusk/nightfall, with Saturn at top and Venus at bottom. Day by day, Venus climbs upward, toward Jupiter, until Venus and Jupiter meet up for a conjunction on November 24. Mercury crosses the sun’s disk on November 11. Throughout the month, Mars climbs out of the glare of sunrise. Click here for recommended almanacs; they can help you know when the planets rise and set in your sky.

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Watch for the young crescent moon near Jupiter on October 30 and 31, and then near Saturn on November 1 and 2. Read more.

Click the name of a planet to learn more about its visibility in November 2019: Venus, Jupiter, Saturn, Mars and Mercury.

Jupiter – the second-brightest planet after Venus – adorns the western sky at dusk and nightfall. Venus lurks below Jupiter nearly all month long, until these two dazzling beauties meet up for a conjunction on November 24, 2019. By the month’s end, Venus will have moved above Jupiter in the evening sky.

Jupiter pops out at dusk – brighter than any star – and stays out until early evening at mid-northern latitudes (mid-evening at temperate latitudes in the Southern Hemisphere). Not sure which one is Jupiter? See the moon in Jupiter’s vicinity for several days, centered on or near Halloween and then again on or near November 27.

Need more confirmation? Find a bright object you think is Jupiter, steady your binoculars – maybe sit down and anchor them on your knees, or prop your elbows on a fence railing – and aim them at that very bright light. If it is Jupiter, at least one or more of its four largest moons should pop into view.

At mid-northern latitudes in the Northern Hemisphere, Jupiter appears in the southwest sky at dusk. In early November, Jupiter sets around 7 to 8 p.m. (8 to 9 p.m. daylight saving time). By the month’s end, Jupiter sets at nightfall, around 6 p.m.

At temperate latitudes in the Southern Hemisphere, the king planet stays out till around 10 p.m. in early November, and by late November, Jupiter sets at nightfall, or around 8 p.m.

Try Stellarium Online for the view from your location.

At nightfall and early evening – November 1 and 2, 2019 – the waxing crescent moon shines in the vicinity of the planet Saturn, and the dazzling planet Jupiter sits below the moon and Saturn, fairly close to the horizon. Read more.

Saturn. After you find Jupiter at dusk and nightfall, use this brilliant beauty of a planet to find another bright evening planet, Saturn. Saturn is not as bright as Jupiter, but the ringed planet shines on a par with the sky’s brightest stars. Hold your fist at arm’s length. Saturn is roughly two fist-widths to the east of (or above) Jupiter. Because Saturn is the only bright-looking “star” to occupy this part of the sky, you’re not likely to mistake a bright star for Saturn.

Read more: When Jupiter and Saturn meet

Saturn – a golden world to the eye alone – pops out at nightfall and stays out well after nightfall. This planet still shines as brightly as a 1st-magnitude star, in other words, as brightly as our sky’s brightest stars.

Viewing Saturn’s rings soon? Read me 1st

At mid-northern latitudes, Saturn plunges below the horizon around 9 p.m. (10 p.m. daylight saving time) in early November. Near the month’s end, Saturn sets around 7 to 8 p.m.

At temperate latitudes in the Southern Hemisphere, in early November, Saturn sinks below the horizon near the midnight hour. (Midnight in this usage means midway between sunset and sunrise.) By the month’s end, Saturn sets around 9 to 10 p.m.

You won’t mistake Jupiter for Saturn. Jupiter is significantly the brighter of these two worlds. The king planet Jupiter ranks as the fourth-brightest celestial object after the sun, moon and Venus, outshining Saturn by about 10 times. What’s more, at nightfall and early evening in November 2019, Jupiter shines well to the west of Saturn.

Watch for the waxing crescent moon to join up with Saturn in early November, as shown on the sky chart above, and then again at the month’s end, as shown on the sky chart below.

Watch for the young moon to fly by Jupiter, Venus and Saturn in late November 2019. By the month’s end, Venus will have climbed above Jupiter in the evening sky. Read more.

Venus – the brightest planet – climbs out of the glare of evening dusk throughout the month, becoming more prominent in the evening sky in late November. Venus starts out the month below Jupiter, the second-brightest planet after Venus. But watch for Venus to soar upward day by day while Jupiter sinks downward. These two dazzling beauties will meet up for a close-knit conjunction on November 24, 2019, as shown on the sky chart below. By the month’s end, Venus hovers over Jupiter, as she reclaims her stature as the evening “star.”

At mid-northern latitudes in early November, Venus sets about one hour after sunset; but by the month’s end, that’ll increase to nearly two hours.

At temperate latitudes in the Southern Hemisphere, Venus sets about 1 1/2 hours after the sun in early November, and some two hours after sunset by the month’s end.

Watch for the young waxing crescent moon to pair up with Venus on or near November 28, as shown on the chart above.

It should be grand viewing Venus and Jupiter in conjunction in the evening twilight on November 24, 2019. After all, Venus and Jupiter rank as the 3rd-brightest and 4th-brightest heavenly bodies, respectively, after the sun and moon. Read more.

Transit of Mercury from San Juan, Puerto Rico – May 9, 2016 – by Fernando Roquel Torres. The next transit of Mercury will take place on November 11, 2019. Read more.

Mercury shifts from the evening sky to the morning sky on November 11, 2019. Most of the time, as seen from Earth, Mercury swings to the north or south of the sun as its transitions over to the morning sky at inferior conjunction (see diagram below). But not this time! Mercury passes directly in front of the sun, to show itself as a small black dot crossing the solar disk. You need an optical aid and proper eye protection to safely watch this transit of Mercury.

Read more: Transit of Mercury on November 11, 2019

This diagram depicts an inferior conjunction of Venus or Mercury. At such times, the inner planet passes between the Earth and sun. Image via COSMOS.

From southerly latitudes, it may be possible to catch Mercury after sunset in early November; and, from northerly latitudes, to view Mercury before sunrise during the last week or two of November. Watch for the waning crescent moon to pair up with Mercury around November 24 or 25, as shown on the sky chart below.

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

Where is Mars? Sitting in the glare of morning twilight, modestly-bright Mars slowly climbs out the glare of morning twilight throughout November. Mars is more easily seen from the Northern Hemisphere and southern tropics than at temperate latitudes in the Southern Hemisphere. At mid-northern latitudes, Mars rises about two hours before the sun in early November, and by the month’s end, rises some 2 1/2 hours before.

At temperate latitudes in the Southern Hemisphere, Mars comes up about one hour before the sun in early November, and about 1 1/2 hours before sunrise at the month’s end.

Watch for the old waning crescent moon to couple up with Mars on or near November 25, as shown on the above sky chart.

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: In November 2019, a line-up three planets – Saturn, Jupiter and Venus – adorns the sky at dusk/nightfall, with Saturn at top and Venus at bottom. Day by day, Venus climbs upward, toward Jupiter, until Venus and Jupiter meet up for a conjunction on November 24. Mercury crosses the sun’s disk on November 11. Throughout the month, Mars climbs out of the glare of sunrise. Click here for recommended almanacs; they can help you know when the planets rise and set in your sky.

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