Did colliding dark matter shape the El Gordo galaxy cluster?

This Hubble Space Telescope image shows the most massive cluster of galaxies in existence yet known. It existed when the universe was less than half its current age of 13.8 billion years. The cluster – El Gordo, Spanish for the fat one – contains several hundred galaxies swarming around under a collective gravitational pull. A new paper suggests self-interacting dark matter explains the cluster’s internal interactions. Image via NASA/ ESA/ J. Jee (University of California, Davis).

• A new study suggests dark matter may have collisional properties, challenging the standard cosmological model.
• The study analyzed the behavior of dark matter in the El Gordo cluster, supporting the self-interacting dark matter theory.
• Massive galaxy clusters like El Gordo provide valuable insights into the collisional properties of dark matter.

Self-interacting dark matter explains El Gordo

Scientists think 27% of the universe consists of dark matter, a mysterious but unseen substance. And if dark matter can interact with itself, it may explain the behavior of the biggest galaxy clusters in the universe.

That’s the insight Riccardo Valdarnini at the Scuola Internazionale Superiore di Studi Avanzati (SISSA) in Trieste, Italy, reported in a recent analysis late last month. Valdarnini looked at mass concentrations in the El Gordo galaxy cluster. He found the distribution supports a model of self-interacting dark matter (SIDM). The peer-reviewed journal Astronomy and Astrophysics published the study on April 12, 2024.

El Gordo – Spanish for the fat one and cataloged as ACT-CL J0102-4915 – is the largest known merger of galaxy clusters yet observed. Measurements from the Hubble Space Telescope suggest El Gordo, which sits 9.7 billion light-years from Earth, contains 3 million billion (3,000,000,000,000,000) times the mass of our sun. But only part of that is regular matter. Most of it – about 90%, according to Valdarnini – is invisible dark matter.

Cold dark matter clumps up too much

Valdarnini’s work on the mass distribution in El Gordo strongly suggests bits of dark matter are colliding with each other. Those interactions helped shape El Gordo’s ultimate form. He explained what he found in a SISSA news release from May:

The calculations indicated that in this cluster the observed physical separation between the points of maximum density of dark matter and those of the other mass components can be explained using the so-called SIDM (self-interacting dark matter) model, as opposed to the standard one.

The standard explanation – cold dark matter (CDM) – says the stuff doesn’t play well with others. It only interacts gravitationally with regular matter but doesn’t appear to come into contact with it or with itself. But that’s not what we find in El Gordo.

The most significant result of this simulation study is that the relative separations observed between the different mass centroids of the El Gordo cluster are naturally explained if the dark matter is self-interacting.

Invisible mass makes El Gordo lopsided

The mass of El Gordo has three parts: galaxies, gas and dark matter. Under the CDM model, the center of mass for the galaxies and dark matter should be same. In the SIDM model, however, they should be different. And that’s what the mathematical models of the El Gordo data shows.

A noteworthy feature is the peak location of the different mass components. At variance with what we see in the Bullet Cluster, another important example of a colliding cluster, the X-ray peak (from El Gordo) precedes the southeast dark matter peak.

That means, Valdarnini says, we’ve probably found self-interacting dark matter in El Gordo.

For this reason, these findings provide an unambiguous signature of a dark matter behavior that exhibits collisional properties in a very energetic high-redshift cluster collision.

Yet there’s still work to do, he notes. His simulation numbers for El Gordo don’t quite match up perfectly to observation.

This suggests that present SIDM models should be considered as only a low order approximation. And the underlying physical processes that describe the interaction of dark matter in major cluster mergers are more complex than can be adequately represented by the commonly assumed approach based on the scattering of dark matter particles.

That said, Valdarnini’s work provides strong evidence that dark matter does interact with itself. And knowing that could lead to a new understanding of a vast and invisible portion of our universe.

Bottom line: A recently published analysis of the El Gordo galaxy cluster suggests its internal behavior might be a result of self-interacting dark matter (SIDM).

Read more: Dark matter, a mysterious substance … What is it?

Source: An N-body/hydrodynamical simulation study of the merging cluster El Gordo: A compelling case for self-interacting dark matter?

Via Scuola Internazionale Superiore di Studi Avanzati (SISSA)

The post Did colliding dark matter shape the El Gordo galaxy cluster? first appeared on EarthSky.

from EarthSky https://ift.tt/A1pwxJn

This Hubble Space Telescope image shows the most massive cluster of galaxies in existence yet known. It existed when the universe was less than half its current age of 13.8 billion years. The cluster – El Gordo, Spanish for the fat one – contains several hundred galaxies swarming around under a collective gravitational pull. A new paper suggests self-interacting dark matter explains the cluster’s internal interactions. Image via NASA/ ESA/ J. Jee (University of California, Davis).

• A new study suggests dark matter may have collisional properties, challenging the standard cosmological model.
• The study analyzed the behavior of dark matter in the El Gordo cluster, supporting the self-interacting dark matter theory.
• Massive galaxy clusters like El Gordo provide valuable insights into the collisional properties of dark matter.

Self-interacting dark matter explains El Gordo

Scientists think 27% of the universe consists of dark matter, a mysterious but unseen substance. And if dark matter can interact with itself, it may explain the behavior of the biggest galaxy clusters in the universe.

That’s the insight Riccardo Valdarnini at the Scuola Internazionale Superiore di Studi Avanzati (SISSA) in Trieste, Italy, reported in a recent analysis late last month. Valdarnini looked at mass concentrations in the El Gordo galaxy cluster. He found the distribution supports a model of self-interacting dark matter (SIDM). The peer-reviewed journal Astronomy and Astrophysics published the study on April 12, 2024.

El Gordo – Spanish for the fat one and cataloged as ACT-CL J0102-4915 – is the largest known merger of galaxy clusters yet observed. Measurements from the Hubble Space Telescope suggest El Gordo, which sits 9.7 billion light-years from Earth, contains 3 million billion (3,000,000,000,000,000) times the mass of our sun. But only part of that is regular matter. Most of it – about 90%, according to Valdarnini – is invisible dark matter.

Cold dark matter clumps up too much

Valdarnini’s work on the mass distribution in El Gordo strongly suggests bits of dark matter are colliding with each other. Those interactions helped shape El Gordo’s ultimate form. He explained what he found in a SISSA news release from May:

The calculations indicated that in this cluster the observed physical separation between the points of maximum density of dark matter and those of the other mass components can be explained using the so-called SIDM (self-interacting dark matter) model, as opposed to the standard one.

The standard explanation – cold dark matter (CDM) – says the stuff doesn’t play well with others. It only interacts gravitationally with regular matter but doesn’t appear to come into contact with it or with itself. But that’s not what we find in El Gordo.

The most significant result of this simulation study is that the relative separations observed between the different mass centroids of the El Gordo cluster are naturally explained if the dark matter is self-interacting.

Invisible mass makes El Gordo lopsided

The mass of El Gordo has three parts: galaxies, gas and dark matter. Under the CDM model, the center of mass for the galaxies and dark matter should be same. In the SIDM model, however, they should be different. And that’s what the mathematical models of the El Gordo data shows.

A noteworthy feature is the peak location of the different mass components. At variance with what we see in the Bullet Cluster, another important example of a colliding cluster, the X-ray peak (from El Gordo) precedes the southeast dark matter peak.

That means, Valdarnini says, we’ve probably found self-interacting dark matter in El Gordo.

For this reason, these findings provide an unambiguous signature of a dark matter behavior that exhibits collisional properties in a very energetic high-redshift cluster collision.

Yet there’s still work to do, he notes. His simulation numbers for El Gordo don’t quite match up perfectly to observation.

This suggests that present SIDM models should be considered as only a low order approximation. And the underlying physical processes that describe the interaction of dark matter in major cluster mergers are more complex than can be adequately represented by the commonly assumed approach based on the scattering of dark matter particles.

That said, Valdarnini’s work provides strong evidence that dark matter does interact with itself. And knowing that could lead to a new understanding of a vast and invisible portion of our universe.

Bottom line: A recently published analysis of the El Gordo galaxy cluster suggests its internal behavior might be a result of self-interacting dark matter (SIDM).

Read more: Dark matter, a mysterious substance … What is it?

Source: An N-body/hydrodynamical simulation study of the merging cluster El Gordo: A compelling case for self-interacting dark matter?

Via Scuola Internazionale Superiore di Studi Avanzati (SISSA)

The post Did colliding dark matter shape the El Gordo galaxy cluster? first appeared on EarthSky.

from EarthSky https://ift.tt/A1pwxJn

Full moon in June mimics path of December sun

This June’s full moon will occur at 1:08 UTC on June 22, 2024. That is 8:08 p.m. on June 21 in the central United States. The moon will rise in the southeast just after sunset and will lie to the lower left of the bright red star Antares. Chart via EarthSky.

When to watch in 2024: Overnight of June 21.
Where to look: Look for the bright, round moon in the east in the evening, highest in the sky around midnight, and in the west before sunrise on June 22.
Crest of the full moon falls at 1:08 UTC on June 22, 2024. That’s 8:08 p.m. CDT on June 21 in central North America. So, if you live in either North or South America, your fullest moon hangs in the southeast after sunset on June 21.

In fact, all full moons rise along the eastern horizon near sunset, and set along the western horizon near sunrise. And they are visible all night as they trek across the sky. At full moon, the sun, Earth, and moon are aligned in space with Earth in the middle. That’s because the moon’s day side – its fully lighted hemisphere – directly faces us. That’s why the moon appears full. Also note that the moon will look full and round for a day or two before and after the crest of the full moon.

At full moon, the sun, Earth, and moon are aligned with Earth in the middle. The moon’s day side – its fully lighted hemisphere – directly faces us. Chart via EarthSky.

It’s the Strawberry Moon

All full moons have names. In Europe, popular names for the June full moon include the Honey Moon and the Mead Moon. Some Native Americans used the name Strawberry Moon for the June full moon, and that name is still the most common in North America. The name Strawberry Moon highlights the time of year when many species of berries ripen, particularly sweet strawberries.

June full moon is in Sagittarius in 2024

The June 2024 full moon can lie in front of one of three constellations of the zodiac. First, it can lie in the constellation Scorpius the Scorpion. The second is the lesser-known constellation Ophiuchus the Serpent Bearer. And the third is Sagittarius the Archer.

As seen from the Americas, the full moon on the night of June 21, 2024, will be located in the direction of Sagittarius and in the foot of its Teapot asterism. This June full moon also happens to lie almost in the direction of the center of our galaxy, the Milky Way.

You’ll notice a bright star to the moon’s west. It’s Antares, the brightest star of Sagittarius’ neighboring constellation, Scorpius. It is known as the Scorpion’s Heart.

The 2024 June full moon falls on the overnight of June 21 and lies in the constellation Sagittarius. Chart via EarthSky.

June full moon mimics December sun

And because a full moon stays more or less opposite the sun, the full moon’s nighttime path mimics the sun’s daytime path from six months ago, or six months hence.

This full moon occurs very close to the June solstice, so the moon follows nearly the same path across the sky as the December solstice sun. The December solstice is the Northern Hemisphere’s winter solstice. Thus, the moon’s trek on the nights around the June full moon will resemble the low path of the winter solstice sun.

North of the Arctic Circle, the wintertime sun never climbs above the horizon. So neither will this June full moon.

Meanwhile in the Southern Hemisphere, the June full moon’s flight across the sky will mirror that of the high summer solstice sun.

And, south of the Antarctic Circle, the moon will be out for 24 hours around the clock, simulating the midnight sun of summer.

Arc of the June full moon

The moon’s arc across our sky varies from month to month and season to season. Every full moon rises along the eastern horizon, opposite the sun as it sets in the west. And every full moon arcs across the sky throughout the night, and sets along the western horizon around dawn. So for viewers in the Northern Hemisphere, the arc of June’s full moon is lower than the paths of the full moons since December.

For observers in the Northern Hemisphere, the low arc across the sky of the June full moon closely matches that of the December sun. The arc of the June sun is always much higher than the arc of the June full moon, and matches that of the December full moon. Chart via EarthSky.

On the other hand, for those in the Southern Hemisphere, the full moon’s arc across the sky is climbing higher with each successive month since December. So, it reaches its highest at the full moon falling closest to the June solstice, which occurs sometime from mid-June through early July. In 2024, the June 21 full moon is just one day after the solstice.

For observers in the Southern Hemisphere, the high arc across the sky of the June full moon closely matches that of the December sun. The arc of the June sun is always much lower than the arc of the June full moon, and matches that of the December full moon. Chart via EarthSky.

Bottom line: The June full moon – the Strawberry Moon – will occur overnight on June 21-22, 2024 and will lie in the constellation of Sagittarius.

The post Full moon in June mimics path of December sun first appeared on EarthSky.

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This June’s full moon will occur at 1:08 UTC on June 22, 2024. That is 8:08 p.m. on June 21 in the central United States. The moon will rise in the southeast just after sunset and will lie to the lower left of the bright red star Antares. Chart via EarthSky.

When to watch in 2024: Overnight of June 21.
Where to look: Look for the bright, round moon in the east in the evening, highest in the sky around midnight, and in the west before sunrise on June 22.
Crest of the full moon falls at 1:08 UTC on June 22, 2024. That’s 8:08 p.m. CDT on June 21 in central North America. So, if you live in either North or South America, your fullest moon hangs in the southeast after sunset on June 21.

In fact, all full moons rise along the eastern horizon near sunset, and set along the western horizon near sunrise. And they are visible all night as they trek across the sky. At full moon, the sun, Earth, and moon are aligned in space with Earth in the middle. That’s because the moon’s day side – its fully lighted hemisphere – directly faces us. That’s why the moon appears full. Also note that the moon will look full and round for a day or two before and after the crest of the full moon.

At full moon, the sun, Earth, and moon are aligned with Earth in the middle. The moon’s day side – its fully lighted hemisphere – directly faces us. Chart via EarthSky.

It’s the Strawberry Moon

All full moons have names. In Europe, popular names for the June full moon include the Honey Moon and the Mead Moon. Some Native Americans used the name Strawberry Moon for the June full moon, and that name is still the most common in North America. The name Strawberry Moon highlights the time of year when many species of berries ripen, particularly sweet strawberries.

June full moon is in Sagittarius in 2024

The June 2024 full moon can lie in front of one of three constellations of the zodiac. First, it can lie in the constellation Scorpius the Scorpion. The second is the lesser-known constellation Ophiuchus the Serpent Bearer. And the third is Sagittarius the Archer.

As seen from the Americas, the full moon on the night of June 21, 2024, will be located in the direction of Sagittarius and in the foot of its Teapot asterism. This June full moon also happens to lie almost in the direction of the center of our galaxy, the Milky Way.

You’ll notice a bright star to the moon’s west. It’s Antares, the brightest star of Sagittarius’ neighboring constellation, Scorpius. It is known as the Scorpion’s Heart.

The 2024 June full moon falls on the overnight of June 21 and lies in the constellation Sagittarius. Chart via EarthSky.

June full moon mimics December sun

And because a full moon stays more or less opposite the sun, the full moon’s nighttime path mimics the sun’s daytime path from six months ago, or six months hence.

This full moon occurs very close to the June solstice, so the moon follows nearly the same path across the sky as the December solstice sun. The December solstice is the Northern Hemisphere’s winter solstice. Thus, the moon’s trek on the nights around the June full moon will resemble the low path of the winter solstice sun.

North of the Arctic Circle, the wintertime sun never climbs above the horizon. So neither will this June full moon.

Meanwhile in the Southern Hemisphere, the June full moon’s flight across the sky will mirror that of the high summer solstice sun.

And, south of the Antarctic Circle, the moon will be out for 24 hours around the clock, simulating the midnight sun of summer.

Arc of the June full moon

The moon’s arc across our sky varies from month to month and season to season. Every full moon rises along the eastern horizon, opposite the sun as it sets in the west. And every full moon arcs across the sky throughout the night, and sets along the western horizon around dawn. So for viewers in the Northern Hemisphere, the arc of June’s full moon is lower than the paths of the full moons since December.

For observers in the Northern Hemisphere, the low arc across the sky of the June full moon closely matches that of the December sun. The arc of the June sun is always much higher than the arc of the June full moon, and matches that of the December full moon. Chart via EarthSky.

On the other hand, for those in the Southern Hemisphere, the full moon’s arc across the sky is climbing higher with each successive month since December. So, it reaches its highest at the full moon falling closest to the June solstice, which occurs sometime from mid-June through early July. In 2024, the June 21 full moon is just one day after the solstice.

For observers in the Southern Hemisphere, the high arc across the sky of the June full moon closely matches that of the December sun. The arc of the June sun is always much lower than the arc of the June full moon, and matches that of the December full moon. Chart via EarthSky.

Bottom line: The June full moon – the Strawberry Moon – will occur overnight on June 21-22, 2024 and will lie in the constellation of Sagittarius.

The post Full moon in June mimics path of December sun first appeared on EarthSky.

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Katmai bear cam season begins now! Livestream here

Watch a bear cam above or visit Explore.org for all 8 bear cams.

Bear cam livestream begins again

Returning for a 12th season, the world-famous bear cam livestream at Katmai National Park in Alaska begins on June 20, 2024. The bear cams go live at 8 a.m. Alaska Daylight Time, or 11 a.m. CDT. Explore.org established the bear cams in 2012. The cams are situated along the Brooks River and at Brook Falls, where brown bears await salmon swimming upstream. Eight cameras will capture the action this year as bears compete for their supper. But you can also see other wildlife on the livestream, from eagles to gulls to the occasional wolf.

Brown bears come to Brooks Falls starting in late June because that’s when the salmon start migrating. By late summer, the salmon spawn and begin to die. So, in September and October, bear activity moves to the lower Brooks River. There, the bears search for dead and dying salmon near the mouth of the river. The most active months on the bear cams are July and September. Also, bears are diurnal, meaning they’re most active during the day. A bear at Brooks Falls can catch and eat more than 30 salmon a day.

Don’t forget, in the fall, to follow along with Fat Bear Week. That’s when the park shares before-and-after pictures, showing how much the bears have plumped up over a summer of engorging themselves. The public gets to vote on which bear they think did the best job of preparing for winter.

The brown bears at Brooks Falls begin actively feeding on salmon in late June. You can watch them on the Katmai bear cam. Image via NPS.

Brown bears on the bear cam

Alaska’s brown bears are those that live near the coast and eat salmon. Sometimes, people confuse them with grizzly bears. Grizzly bears in Alaska live farther inland, however. All grizzly bears are brown bears. However, not all brown bears are grizzly bears. The brown bears of Alaska are larger than the inland grizzlies.

Sometimes brown bears snorkel for fish. Image via NPS/ M. Fitz.

Brooks Falls in Katmai

Brooks Falls has long been a popular spot to view brown bears in Alaska. The National Park Service hosts visitors at Brooks Camp on the Brooks River, where they’ve built boardwalks and viewing platforms for easier access to bear-gazing. There are north and south platforms near the camp at the mouth of the river and Naknek Lake, plus platforms at the falls itself and one downstream in the riffles, where less competitive bears come for meals. The National Park Service estimates there are about 2,200 bears in the park, with more bears than people living on the Alaskan Peninsula.

See that white patch near the center of this river? That’s Brooks Falls on the Brooks River in Katmai National Park, Alaska. Water flows from Lake Brooks at the right to Naknek Lake on the left. Image via NPS/ Roy Wood.

Valley of Ten Thousand Smokes

But Katmai is more than just bear territory. The U.S. government first set aside the land of Katmai in 1918 to protect the area around Novarupta volcano. In 1912, Novarupta exploded in the largest volcano eruption of the 20th century. For 60 hours, starting on June 6, the volcano spewed magma and ash, eventually releasing more than 30 times the output of the 1980 eruption of Mount St. Helens.

Scientists Robert F. Griggs visited the area four years later and was awed by the devastation, giving the area its nickname of Valley of Ten Thousand Smokes. Griggs wrote:

The sight that flashed into view … was one of the most amazing visions ever beheld by mortal eye. The whole valley as far as the eye could reach was full of hundreds, no thousands – literally tens of thousands – of smokes curling up from its fissured floor … It was as though all the steam engines in the world, assembled together, had popped their safety valves at once and were letting off surplus steam in concert.

Our feeling of admiration [for the Valley] soon gave way to one of stupefaction. We were overawed. For a while we could neither think nor act in a normal fashion.

NASA used this decimated landscape to train Apollo astronauts in 1965 and 1966.

Bottom line: The world-famous Katmai bear cam season begins on June 20, 2024. Find the livestream here and learn more about brown bears and Katmai National Park.

The post Katmai bear cam season begins now! Livestream here first appeared on EarthSky.

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Watch a bear cam above or visit Explore.org for all 8 bear cams.

Bear cam livestream begins again

Returning for a 12th season, the world-famous bear cam livestream at Katmai National Park in Alaska begins on June 20, 2024. The bear cams go live at 8 a.m. Alaska Daylight Time, or 11 a.m. CDT. Explore.org established the bear cams in 2012. The cams are situated along the Brooks River and at Brook Falls, where brown bears await salmon swimming upstream. Eight cameras will capture the action this year as bears compete for their supper. But you can also see other wildlife on the livestream, from eagles to gulls to the occasional wolf.

Brown bears come to Brooks Falls starting in late June because that’s when the salmon start migrating. By late summer, the salmon spawn and begin to die. So, in September and October, bear activity moves to the lower Brooks River. There, the bears search for dead and dying salmon near the mouth of the river. The most active months on the bear cams are July and September. Also, bears are diurnal, meaning they’re most active during the day. A bear at Brooks Falls can catch and eat more than 30 salmon a day.

Don’t forget, in the fall, to follow along with Fat Bear Week. That’s when the park shares before-and-after pictures, showing how much the bears have plumped up over a summer of engorging themselves. The public gets to vote on which bear they think did the best job of preparing for winter.

The brown bears at Brooks Falls begin actively feeding on salmon in late June. You can watch them on the Katmai bear cam. Image via NPS.

Brown bears on the bear cam

Alaska’s brown bears are those that live near the coast and eat salmon. Sometimes, people confuse them with grizzly bears. Grizzly bears in Alaska live farther inland, however. All grizzly bears are brown bears. However, not all brown bears are grizzly bears. The brown bears of Alaska are larger than the inland grizzlies.

Sometimes brown bears snorkel for fish. Image via NPS/ M. Fitz.

Brooks Falls in Katmai

Brooks Falls has long been a popular spot to view brown bears in Alaska. The National Park Service hosts visitors at Brooks Camp on the Brooks River, where they’ve built boardwalks and viewing platforms for easier access to bear-gazing. There are north and south platforms near the camp at the mouth of the river and Naknek Lake, plus platforms at the falls itself and one downstream in the riffles, where less competitive bears come for meals. The National Park Service estimates there are about 2,200 bears in the park, with more bears than people living on the Alaskan Peninsula.

See that white patch near the center of this river? That’s Brooks Falls on the Brooks River in Katmai National Park, Alaska. Water flows from Lake Brooks at the right to Naknek Lake on the left. Image via NPS/ Roy Wood.

Valley of Ten Thousand Smokes

But Katmai is more than just bear territory. The U.S. government first set aside the land of Katmai in 1918 to protect the area around Novarupta volcano. In 1912, Novarupta exploded in the largest volcano eruption of the 20th century. For 60 hours, starting on June 6, the volcano spewed magma and ash, eventually releasing more than 30 times the output of the 1980 eruption of Mount St. Helens.

Scientists Robert F. Griggs visited the area four years later and was awed by the devastation, giving the area its nickname of Valley of Ten Thousand Smokes. Griggs wrote:

The sight that flashed into view … was one of the most amazing visions ever beheld by mortal eye. The whole valley as far as the eye could reach was full of hundreds, no thousands – literally tens of thousands – of smokes curling up from its fissured floor … It was as though all the steam engines in the world, assembled together, had popped their safety valves at once and were letting off surplus steam in concert.

Our feeling of admiration [for the Valley] soon gave way to one of stupefaction. We were overawed. For a while we could neither think nor act in a normal fashion.

NASA used this decimated landscape to train Apollo astronauts in 1965 and 1966.

Bottom line: The world-famous Katmai bear cam season begins on June 20, 2024. Find the livestream here and learn more about brown bears and Katmai National Park.

The post Katmai bear cam season begins now! Livestream here first appeared on EarthSky.

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It’s summer. What’s noon to you? Midday? High noon?

What is noon to you? Image via Scott Webb/ Pexels.com. Used with permission.

What is noon to you?

When is it noon for you? That’s not as easy a question to answer as you might think! What do you mean by noon? Do you define it by your clock or smartphone? Or the gnawing in your stomach that says it’s time for lunch? Well, you might want to think again!

We in the Northern Hemisphere typically say the first day of summer comes at the June solstice, which, in 2024, falls on June 20. But – no matter what day it is – when noon occurs depends in part on your location and in part on your definition of noon. On the day of a June solstice, noontime shadows are just a hair shorter than the day before. That’s because, at the June solstice, Earth’s Northern Hemisphere is tilted most sunward for the year, and the sun rises highest in our Northern Hemisphere sky, yielding the year’s shortest midday shadows.

Notice that I said midday, rather than just noon. Usually when most of us say noon, we mean 12 p.m. on the clock. But that may not be what astronomers mean by noon.

Shadows at noon are shortest around the June solstice

Around the time of the June solstice, shadows are shortest when the sun is due south in the sky. We say that the sun is crossing the meridian. But the sun’s meridian crossing rarely occurs at exactly straight-up noon, according to the clock. The time at which the sun crosses the meridian used to be called high noon because that is when the sun is highest in the sky. Today, we astronomers sometimes refer to it as transit time or local solar noon. Of course, shadows will vary by your location on the globe.

You can perform an experiment yourself

In fact, you can perform an experiment that simulates an observation by Eratosthenes more than 2,000 years ago, through which he obtained the first accurate measurement of the size of the Earth.

You can construct a simple device called a gnomon (pronounced NO-mun) or shadow stick to calculate how high the sun is, with simple trigonometry. Just measure the height of the gnomon (H) and the length of the shadow (L) at local solar noon. Then the angular height of the sun is the arctangent of H/L. For accuracy, the gnomon must be very straight, the ground level, and the measurements precise. For example, in Denver, it will be about 73.75 degrees high. How high is it where you live?

But before you can make the measurement, you need to know when local solar noon occurs where you are located. Before the invention of the telegraph in the 19th century, every locality defined noon by the time when the sun crossed the meridian. Because of geographical location, when the sun crosses the meridian as seen in Denver, in Grand Junction (about 180 miles to the west) the sun hasn’t reached the meridian yet, and won’t for another 14 minutes or so. It takes about 14 minutes for the Earth to turn far enough to bring the sun to the meridian in Grand Junction after it passes the meridian in Denver.

Why we have time zones

At a time when the fastest form of communication was a stagecoach or the Pony Express, this difference in time did not matter. But when near-instantaneous communication became available with the telegraph, people gradually realized that a standardization of time was necessary. Thus, the concept of time zones was developed in 1884, but not adopted officially in the U.S. until 1918.

But even considering time zones, the actual time of transit varies through the year because of the Earth’s varying speed in its orbit around the sun. At times the planet has to turn a bit more from one transit to the next, and at times it needs to turn a bit less. This is because the change in Earth’s speed (due to varying distance to the sun through the year) causes the sun’s apparent motion across the sky to change.

There is also a variation due to the tilt of the Earth that affects the sun’s apparent motion in the sky. That means that the real sun (which crosses the meridian at local solar noon) is as much as 16 minutes faster or slower than the steady but fictitious mean sun that defines clock-time noon for the various time zones.

And don’t forget daylight saving time

And then, of course, there is the complication of daylight saving time, which really saves nothing but merely offsets the clocks by an hour.

Now you can make all the calculations to figure out transit time or local solar noon for yourself, but you don’t need to go to the trouble. Just go to the sunrise sunset calendar website and have it calculated it for you.

Here are some examples of typical transit times, or local solar noons, for June 20, as calculated by the Sunrise Sunset Calendar website:

Eastern Time Zone		Central Time Zone		Mountain Time Zone		Pacific Time Zone
New York	12:58 p.m	Chicago	12:52 p.m.	Denver	1:02 p.m.	Los Angeles	12:55 p.m.
Miami	1:22 p.m.	Little Rock	1:11 p.m.	Albuquerque	1:08 p.m.	Seattle	1:11 p.m.
Detroit	1:34 p.m.	Kansas City (KS)	1:21 p.m.	Salt Lake City	1:29 p.m.	San Francisco	1:11 p.m.
Atlanta	1:39 p.m.	Houston	1:23 p.m.	Phoenix	12:30 p.m. *	Portland	1:11 p.m.

* Note that Phoenix is on Standard, not Daylight, Time. Also note that the exact moment of the summer solstice is not related to the time of local solar noon.

Oh, and by the way, if you’re out in the sun – contemplating the passage of the sun and the time of noon for you – don’t forget your sunscreen.

Bottom line: What is the definition of noon? An exploration of how astronomers think about noontime.

Read more: Equation of time: Why times vary for your high noon by Guy Ottwell

The post It’s summer. What’s noon to you? Midday? High noon? first appeared on EarthSky.

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What is noon to you? Image via Scott Webb/ Pexels.com. Used with permission.

What is noon to you?

When is it noon for you? That’s not as easy a question to answer as you might think! What do you mean by noon? Do you define it by your clock or smartphone? Or the gnawing in your stomach that says it’s time for lunch? Well, you might want to think again!

We in the Northern Hemisphere typically say the first day of summer comes at the June solstice, which, in 2024, falls on June 20. But – no matter what day it is – when noon occurs depends in part on your location and in part on your definition of noon. On the day of a June solstice, noontime shadows are just a hair shorter than the day before. That’s because, at the June solstice, Earth’s Northern Hemisphere is tilted most sunward for the year, and the sun rises highest in our Northern Hemisphere sky, yielding the year’s shortest midday shadows.

Notice that I said midday, rather than just noon. Usually when most of us say noon, we mean 12 p.m. on the clock. But that may not be what astronomers mean by noon.

Shadows at noon are shortest around the June solstice

Around the time of the June solstice, shadows are shortest when the sun is due south in the sky. We say that the sun is crossing the meridian. But the sun’s meridian crossing rarely occurs at exactly straight-up noon, according to the clock. The time at which the sun crosses the meridian used to be called high noon because that is when the sun is highest in the sky. Today, we astronomers sometimes refer to it as transit time or local solar noon. Of course, shadows will vary by your location on the globe.

You can perform an experiment yourself

In fact, you can perform an experiment that simulates an observation by Eratosthenes more than 2,000 years ago, through which he obtained the first accurate measurement of the size of the Earth.

You can construct a simple device called a gnomon (pronounced NO-mun) or shadow stick to calculate how high the sun is, with simple trigonometry. Just measure the height of the gnomon (H) and the length of the shadow (L) at local solar noon. Then the angular height of the sun is the arctangent of H/L. For accuracy, the gnomon must be very straight, the ground level, and the measurements precise. For example, in Denver, it will be about 73.75 degrees high. How high is it where you live?

But before you can make the measurement, you need to know when local solar noon occurs where you are located. Before the invention of the telegraph in the 19th century, every locality defined noon by the time when the sun crossed the meridian. Because of geographical location, when the sun crosses the meridian as seen in Denver, in Grand Junction (about 180 miles to the west) the sun hasn’t reached the meridian yet, and won’t for another 14 minutes or so. It takes about 14 minutes for the Earth to turn far enough to bring the sun to the meridian in Grand Junction after it passes the meridian in Denver.

Why we have time zones

At a time when the fastest form of communication was a stagecoach or the Pony Express, this difference in time did not matter. But when near-instantaneous communication became available with the telegraph, people gradually realized that a standardization of time was necessary. Thus, the concept of time zones was developed in 1884, but not adopted officially in the U.S. until 1918.

But even considering time zones, the actual time of transit varies through the year because of the Earth’s varying speed in its orbit around the sun. At times the planet has to turn a bit more from one transit to the next, and at times it needs to turn a bit less. This is because the change in Earth’s speed (due to varying distance to the sun through the year) causes the sun’s apparent motion across the sky to change.

There is also a variation due to the tilt of the Earth that affects the sun’s apparent motion in the sky. That means that the real sun (which crosses the meridian at local solar noon) is as much as 16 minutes faster or slower than the steady but fictitious mean sun that defines clock-time noon for the various time zones.

And don’t forget daylight saving time

And then, of course, there is the complication of daylight saving time, which really saves nothing but merely offsets the clocks by an hour.

Now you can make all the calculations to figure out transit time or local solar noon for yourself, but you don’t need to go to the trouble. Just go to the sunrise sunset calendar website and have it calculated it for you.

Here are some examples of typical transit times, or local solar noons, for June 20, as calculated by the Sunrise Sunset Calendar website:

Eastern Time Zone		Central Time Zone		Mountain Time Zone		Pacific Time Zone
New York	12:58 p.m	Chicago	12:52 p.m.	Denver	1:02 p.m.	Los Angeles	12:55 p.m.
Miami	1:22 p.m.	Little Rock	1:11 p.m.	Albuquerque	1:08 p.m.	Seattle	1:11 p.m.
Detroit	1:34 p.m.	Kansas City (KS)	1:21 p.m.	Salt Lake City	1:29 p.m.	San Francisco	1:11 p.m.
Atlanta	1:39 p.m.	Houston	1:23 p.m.	Phoenix	12:30 p.m. *	Portland	1:11 p.m.

* Note that Phoenix is on Standard, not Daylight, Time. Also note that the exact moment of the summer solstice is not related to the time of local solar noon.

Oh, and by the way, if you’re out in the sun – contemplating the passage of the sun and the time of noon for you – don’t forget your sunscreen.

Bottom line: What is the definition of noon? An exploration of how astronomers think about noontime.

Read more: Equation of time: Why times vary for your high noon by Guy Ottwell

The post It’s summer. What’s noon to you? Midday? High noon? first appeared on EarthSky.

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Jupiter’s Great Red Spot is 190 years old, scientists say

Today’s Great Red Spot on Jupiter may be 190 years old. Researchers think it’s not the same spot astronomers saw when 1st turning their telescopes on Jupiter in the 1600’s. Image via NASA/ JPL-Caltech/ SwRI/ MSSS/ Gerald Eichstadt/ Justin Cowart.

Jupiter’s Great Red Spot

In the 1600s, astronomers such as Giovanni Domenico Cassini, Robert Hooke and Galileo Galilei first pointed a new instrument called the telescope at the sky and saw a reddish spot on Jupiter. In fact, Cassini – whose observations started in 1665 – called it a “Permanent Spot”. This huge orangish anticyclone is a storm system on the solar system’s largest gas giant planet that has persisted for a few hundred years … or has it? On June 17, 2024, researchers said the Great Red Spot we see today on Jupiter is not the same storm astronomers saw in the 1600s. The researchers said this storm formed some 190 years ago. But that still makes it the longest-lived vortex in the solar system.

The researchers published their peer-reviewed study in Geophysical Research Letters on June 16, 2024.

Hold old is it?

We already knew the size and color of the Great Red Spot have varied over the years. In 1879, scientists estimated the Great Red Spot was 24,200 miles (39,000 km) at its widest. But today the storm is about 8,700 miles (14,000 km) wide and rounder in shape. Currently, it’s about the size of one Earth-diameter.

So, scientists decided to look at the historical record of this fluctuating storm with numerical models in an attempt to explain its nature and longevity. Lead author Agustín Sánchez-Lavega of the University of the Basque Country in Spain said:

From the measurements of sizes and movements, we deduced that it is highly unlikely that the current Great Red Spot was the ‘Permanent Spot’ observed by Giovanni Domenico Cassini. The ‘Permanent Spot’ probably disappeared sometime between the mid-18th and 19th centuries; in which case, we can now say that the longevity of the Red Spot exceeds 190 years.

This sketch by Thomas Gwyn Elger, a 19th century selenographer, shows his view of Jupiter and the Great Red Spot from 1881. The Spot is at the top in this sketch because the artist replicated his inverted view through a telescope. Image via Wikimedia Commons (public domain).

Early observations

The so-called Permanent Spot persisted from the 1600s to about 1713, when astronomers reportedly lost track of it. It was not until more than 100 years later, in 1831, that astronomers again began taking note of an oval storm at around the same latitude as the previous Permanent Spot. So, astronomy historians have long wondered if this was the same spot or a different one cropping up in the same location.

Sánchez-Lavega said:

It has been very motivating and inspiring to turn to the notes and drawings of Jupiter and its Permanent Spot made by the great astronomer Giovanni Domenico Cassini, and to his articles of the second half of the 17th century describing the phenomenon. Others before us had explored these observations, and now we have quantified the results.

Donato Creti’s 1711 painting titled “Jupiter.” It was the 1st depiction of the Great Red Spot as red in color. Image via Wikimedia Commons (public domain).

How did it form?

Recent spacecraft observations show the Great Red Spot is shallow and thin. So researchers used computer modeling to analyze the behavior of thin vortices in the Jovian atmosphere. The researchers had a couple options for how the storm could have formed. It may have been the result of a huge superstorm, a merging of smaller vortices, or perhaps an instability in the winds creating an atmospheric cell.

The modeling showed that anticyclones from superstorms or mergers would result in different properties from the Great Red Spot we see today. But the model of an atmospheric cell produced by an instability from the severe Jovian winds made for a pretty good fit. This model would create a “proto-Great Red Spot”. Then the early form of the Red Spot would eventually shrink, creating a compact and rapidly rotating storm.

And early sketches do show a more elongated Great Red Spot in the past. Plus, scientists have observed other big, elongated cells transform into different vortices on Jupiter.

In the future, scientists would like to learn how the Great Red Spot is so stable. And they’d also like to know if the Great Red Spot will continue to shrink until it disintegrates or if it might find stability and persist for many years to come.

More stats on the Great Red Spot

The fastest winds of the anticyclone roar at about 280 miles per hour (450 km per hour). Its red coloration is due to chemicals in the atmosphere. The strong winds in the vortex stir up ammonia ice particles into the upper layer of clouds. And this exposes them to the sun’s ultraviolet light, giving this region a slight sunburn.

This April 1, 2018, image of the Great Red Spot is courtesy of the Juno spacecraft. Image via NASA/ JPL-Caltech/ SwRI/ MSSS/ Gerald Eichstädt/ Seán Doran.

Bottom line: Scientists said Jupiter’s Great Red Spot has persisted for around 190 years. They believe it’s not the same storm astronomers saw on Jupiter in the 1600s.

Source: The Origin of Jupiter’s Great Red Spot

Via AGU

Read more: Jupiter’s Great Red Spot is shrinking! See photos

The post Jupiter’s Great Red Spot is 190 years old, scientists say first appeared on EarthSky.

from EarthSky https://ift.tt/sUWMQXC

Today’s Great Red Spot on Jupiter may be 190 years old. Researchers think it’s not the same spot astronomers saw when 1st turning their telescopes on Jupiter in the 1600’s. Image via NASA/ JPL-Caltech/ SwRI/ MSSS/ Gerald Eichstadt/ Justin Cowart.

Jupiter’s Great Red Spot

In the 1600s, astronomers such as Giovanni Domenico Cassini, Robert Hooke and Galileo Galilei first pointed a new instrument called the telescope at the sky and saw a reddish spot on Jupiter. In fact, Cassini – whose observations started in 1665 – called it a “Permanent Spot”. This huge orangish anticyclone is a storm system on the solar system’s largest gas giant planet that has persisted for a few hundred years … or has it? On June 17, 2024, researchers said the Great Red Spot we see today on Jupiter is not the same storm astronomers saw in the 1600s. The researchers said this storm formed some 190 years ago. But that still makes it the longest-lived vortex in the solar system.

The researchers published their peer-reviewed study in Geophysical Research Letters on June 16, 2024.

Hold old is it?

We already knew the size and color of the Great Red Spot have varied over the years. In 1879, scientists estimated the Great Red Spot was 24,200 miles (39,000 km) at its widest. But today the storm is about 8,700 miles (14,000 km) wide and rounder in shape. Currently, it’s about the size of one Earth-diameter.

So, scientists decided to look at the historical record of this fluctuating storm with numerical models in an attempt to explain its nature and longevity. Lead author Agustín Sánchez-Lavega of the University of the Basque Country in Spain said:

From the measurements of sizes and movements, we deduced that it is highly unlikely that the current Great Red Spot was the ‘Permanent Spot’ observed by Giovanni Domenico Cassini. The ‘Permanent Spot’ probably disappeared sometime between the mid-18th and 19th centuries; in which case, we can now say that the longevity of the Red Spot exceeds 190 years.

This sketch by Thomas Gwyn Elger, a 19th century selenographer, shows his view of Jupiter and the Great Red Spot from 1881. The Spot is at the top in this sketch because the artist replicated his inverted view through a telescope. Image via Wikimedia Commons (public domain).

Early observations

The so-called Permanent Spot persisted from the 1600s to about 1713, when astronomers reportedly lost track of it. It was not until more than 100 years later, in 1831, that astronomers again began taking note of an oval storm at around the same latitude as the previous Permanent Spot. So, astronomy historians have long wondered if this was the same spot or a different one cropping up in the same location.

Sánchez-Lavega said:

It has been very motivating and inspiring to turn to the notes and drawings of Jupiter and its Permanent Spot made by the great astronomer Giovanni Domenico Cassini, and to his articles of the second half of the 17th century describing the phenomenon. Others before us had explored these observations, and now we have quantified the results.

Donato Creti’s 1711 painting titled “Jupiter.” It was the 1st depiction of the Great Red Spot as red in color. Image via Wikimedia Commons (public domain).

How did it form?

Recent spacecraft observations show the Great Red Spot is shallow and thin. So researchers used computer modeling to analyze the behavior of thin vortices in the Jovian atmosphere. The researchers had a couple options for how the storm could have formed. It may have been the result of a huge superstorm, a merging of smaller vortices, or perhaps an instability in the winds creating an atmospheric cell.

The modeling showed that anticyclones from superstorms or mergers would result in different properties from the Great Red Spot we see today. But the model of an atmospheric cell produced by an instability from the severe Jovian winds made for a pretty good fit. This model would create a “proto-Great Red Spot”. Then the early form of the Red Spot would eventually shrink, creating a compact and rapidly rotating storm.

And early sketches do show a more elongated Great Red Spot in the past. Plus, scientists have observed other big, elongated cells transform into different vortices on Jupiter.

In the future, scientists would like to learn how the Great Red Spot is so stable. And they’d also like to know if the Great Red Spot will continue to shrink until it disintegrates or if it might find stability and persist for many years to come.

More stats on the Great Red Spot

The fastest winds of the anticyclone roar at about 280 miles per hour (450 km per hour). Its red coloration is due to chemicals in the atmosphere. The strong winds in the vortex stir up ammonia ice particles into the upper layer of clouds. And this exposes them to the sun’s ultraviolet light, giving this region a slight sunburn.

This April 1, 2018, image of the Great Red Spot is courtesy of the Juno spacecraft. Image via NASA/ JPL-Caltech/ SwRI/ MSSS/ Gerald Eichstädt/ Seán Doran.

Bottom line: Scientists said Jupiter’s Great Red Spot has persisted for around 190 years. They believe it’s not the same storm astronomers saw on Jupiter in the 1600s.

Source: The Origin of Jupiter’s Great Red Spot

Via AGU

Read more: Jupiter’s Great Red Spot is shrinking! See photos

The post Jupiter’s Great Red Spot is 190 years old, scientists say first appeared on EarthSky.

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New pterosaur species found in Queensland, Australia

An artist’s concept of what the newly discovered pterosaur, Haliskia peterseni, may have looked like in life. Image via Gabriel Ugueto/ Curtin University.

A formidable flying reptile – a pterosaur – once patrolled the skies over an ancient sea. It had a wingspan much larger than that of a pelican, with powerful jaws and tongue for catching fish and cephalopods. When it died, some of its bones were buried in marine sediment and eventually became fossilized. One hundred million years passed. The sea where it lived has long since disappeared and is now an arid expanse in western Queensland, Australia. On June 12, 2024, an international team of researchers said they’ve identified fossils belonging to this flying cousin of dinosaurs.

In 2021, Kevin Petersen, a curator at the Kronosaurus Korner Museum in Queensland, found the pterosaur’s fossilized bones weathering out of some rocks. He carefully excavated it for scientific study. Then, researchers who analyzed the bones discovered the species was new to science. They published their findings in the peer-reviewed journal Scientific Reports/ Springer Nature on June 12, 2024.

Pterosaurs were ancient flying reptiles

When dinosaurs once dominated life on land, large flying reptiles like pterosaurs ruled the skies.

Contrary to popular belief, pterosaurs were not flying dinosaurs. Instead, they were reptiles related to dinosaurs. These creatures, scientists think, were the first vertebrate animals to evolve powered flight. That is, they were able to continually flap their wings to keep themselves aloft for long periods.

Pterosaur fossils have been found worldwide. But they’re relatively rare because their bones are thin and fragile, and therefore often not well-preserved.

These creatures first emerged about 225 million years ago. And they became extinct 66 million years ago, around the same time most dinosaurs perished. But for almost 160 million years, pterosaurs thrived. They evolved to form many different species, ranging in size from a pigeon to a small aircraft.

A new type of pterosaur

Adele Pentland, a graduate student at Curtin University, led the study of the fossil. She was able to identify the specimen as a type of pterosaur called an anhanguerian, based on its skull, teeth and shoulder bones. Other distinctive features about the specimen also indicated it was a new species, unique to the fossil record.

Haliskia peterseni is the name of this new pterosaur species. In their paper, the scientists described the origin of its name. The genus name, Haliskia, is a combination of ancient Greek words that evoke “a flying creature that casts a shadow on the sea.” The species name, peterseni, is in honor of Kevin Petersen who discovered and prepared the fossil.

What scientists know about Haliskia peterseni

Pentland said:

With a wingspan of approximately 4.6 m [15 feet], Haliskia would have been a fearsome predator around 100 million years ago when much of central western Queensland was underwater, covered by a vast inland sea and globally positioned about where Victoria’s southern coastline is today.

She also had these comments about the fossil:

Careful preparation by Mr. Petersen has provided the remains of the most complete specimen of an anhanguerian, and of any pterosaur, discovered in Australia to date.

Haliskia is 22% complete, making it more than twice as complete as the only other known partial pterosaur skeleton found in Australia.

The specimen includes complete lower jaws, the tip of the upper jaw, 43 teeth, vertebrae, ribs, bones from both wings and part of a leg. Also present are very thin and delicate throat bones, indicating a muscular tongue, which helped during feeding on fish and cephalopods.

Pentland provided some additional details about the pterosaur’s head in an interview with the Australian Broadcasting Corporation:

This animal was an adult, with a big head about 60 cm long, or 2 feet, long. And in those jaws were dozens of spike-shaped teeth. So, we looked at the shape of the skull and we think it was probably eating fish and squid-like cephalopods.

Bottom line: A fossil unearthed in western Queensland, Australia, is a new species of pterosaur. Scientists named it Haliskia peterseni.

Source: Haliskia peterseni, a new anhanguerian pterosaur from the late Early Cretaceous of Australia

Via Curtin University

The post New pterosaur species found in Queensland, Australia first appeared on EarthSky.

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An artist’s concept of what the newly discovered pterosaur, Haliskia peterseni, may have looked like in life. Image via Gabriel Ugueto/ Curtin University.

A formidable flying reptile – a pterosaur – once patrolled the skies over an ancient sea. It had a wingspan much larger than that of a pelican, with powerful jaws and tongue for catching fish and cephalopods. When it died, some of its bones were buried in marine sediment and eventually became fossilized. One hundred million years passed. The sea where it lived has long since disappeared and is now an arid expanse in western Queensland, Australia. On June 12, 2024, an international team of researchers said they’ve identified fossils belonging to this flying cousin of dinosaurs.

In 2021, Kevin Petersen, a curator at the Kronosaurus Korner Museum in Queensland, found the pterosaur’s fossilized bones weathering out of some rocks. He carefully excavated it for scientific study. Then, researchers who analyzed the bones discovered the species was new to science. They published their findings in the peer-reviewed journal Scientific Reports/ Springer Nature on June 12, 2024.

Pterosaurs were ancient flying reptiles

When dinosaurs once dominated life on land, large flying reptiles like pterosaurs ruled the skies.

Contrary to popular belief, pterosaurs were not flying dinosaurs. Instead, they were reptiles related to dinosaurs. These creatures, scientists think, were the first vertebrate animals to evolve powered flight. That is, they were able to continually flap their wings to keep themselves aloft for long periods.

Pterosaur fossils have been found worldwide. But they’re relatively rare because their bones are thin and fragile, and therefore often not well-preserved.

These creatures first emerged about 225 million years ago. And they became extinct 66 million years ago, around the same time most dinosaurs perished. But for almost 160 million years, pterosaurs thrived. They evolved to form many different species, ranging in size from a pigeon to a small aircraft.

A new type of pterosaur

Adele Pentland, a graduate student at Curtin University, led the study of the fossil. She was able to identify the specimen as a type of pterosaur called an anhanguerian, based on its skull, teeth and shoulder bones. Other distinctive features about the specimen also indicated it was a new species, unique to the fossil record.

Haliskia peterseni is the name of this new pterosaur species. In their paper, the scientists described the origin of its name. The genus name, Haliskia, is a combination of ancient Greek words that evoke “a flying creature that casts a shadow on the sea.” The species name, peterseni, is in honor of Kevin Petersen who discovered and prepared the fossil.

What scientists know about Haliskia peterseni

Pentland said:

With a wingspan of approximately 4.6 m [15 feet], Haliskia would have been a fearsome predator around 100 million years ago when much of central western Queensland was underwater, covered by a vast inland sea and globally positioned about where Victoria’s southern coastline is today.

She also had these comments about the fossil:

Careful preparation by Mr. Petersen has provided the remains of the most complete specimen of an anhanguerian, and of any pterosaur, discovered in Australia to date.

Haliskia is 22% complete, making it more than twice as complete as the only other known partial pterosaur skeleton found in Australia.

The specimen includes complete lower jaws, the tip of the upper jaw, 43 teeth, vertebrae, ribs, bones from both wings and part of a leg. Also present are very thin and delicate throat bones, indicating a muscular tongue, which helped during feeding on fish and cephalopods.

Pentland provided some additional details about the pterosaur’s head in an interview with the Australian Broadcasting Corporation:

This animal was an adult, with a big head about 60 cm long, or 2 feet, long. And in those jaws were dozens of spike-shaped teeth. So, we looked at the shape of the skull and we think it was probably eating fish and squid-like cephalopods.

Bottom line: A fossil unearthed in western Queensland, Australia, is a new species of pterosaur. Scientists named it Haliskia peterseni.

Source: Haliskia peterseni, a new anhanguerian pterosaur from the late Early Cretaceous of Australia

Via Curtin University

The post New pterosaur species found in Queensland, Australia first appeared on EarthSky.

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Lupus the Wolf, a constellation in southern skies

Lupus the Wolf is a southern constellation with few bright stars. You can see it from the Northern Hemisphere if you live at southerly latitudes such as Florida. Chart via EarthSky.

Lupus is an unassuming constellation whose name means wolf in Latin. The astronomer Ptolemy named Lupus and 47 other constellations in the 2nd century CE. Lupus is boxed in by two larger, brighter and better known constellations: Scorpius and Centaurus.

How to find Lupus the Wolf

Lupus is located south of the ecliptic. If you want to see it, you’ll need to be in the Southern Hemisphere or southward of Florida in the Northern Hemisphere. April through September are the best months to spot Lupus. The Wolf sits beside the constellation Norma the Carpenter’s Square. Scorpius the Scorpion is one of the noticeable constellations that border Lupus, and Centaurus lies on the opposite side.

The stars in Lupus are dim; therefore, you may want to trace out the forms of the Scorpion and Centaur first. Then look toward the dark patch of sky between them. Lupus and Norma both reside here: Lupus has brighter stars and sits farther north than Norma.

Lupus looks vaguely like the wolf it represents. Plus. from the Northern Hemisphere, you may only see the head of the Wolf near Scorpius. From the south, Lupus will be close to overhead on June evenings.

View at EarthSky Community Photos. | Prateek Pandey in Bhopal, India, captured this photo of Lupus and Centaurus on April 18, 2021. He wrote: “The constellation Lupus – its name is Latin for wolf – lies between Scorpius and Centaurus.” Thank you, Prateek!

Stars of the Wolf

The main stars in Lupus are mostly 2nd and 3rd magnitude. The stars near the pincers of Scorpius form a triangle that marks the head of Lupus the Wolf. These stars are Eta Lupi, 440 light-years away, Theta Lupi at a distance of 410 light-years, and Chi Lupi, 470 light-years.

Four stars mark the curve of the Wolf’s body: Gamma Lupi at a distance of 420 light-years, Delta Lupi at 880 light-years and Beta Lupi at 383 light-years. Last is the brightest star in Lupus, magnitude 2.29 Alpha Lupi at a distance of 460 light-years.

Two brighter stars seem to hang down from Beta Lupi and mark the front leg of the wolf. However, these stars are classified as part of Centaurus the Centaur.

If you scan the boundaries of the constellation Lupus with a telescope, you’ll find many double stars and star clusters. Although Lupus is juxtaposed on the Milky Way, it does not have many bright deep-sky observing targets for binocular users.

The stars of Lupus the Wolf. Image via International Astronomical Union/ Sky & Telescope/ Wikimedia Commons (CC BY 3.0).

Bottom line: Lupus the Wolf is a constellation that lies between Scorpius and Centaurus. You have to be farther south on the globe to see the Wolf.

The post Lupus the Wolf, a constellation in southern skies first appeared on EarthSky.

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Lupus the Wolf is a southern constellation with few bright stars. You can see it from the Northern Hemisphere if you live at southerly latitudes such as Florida. Chart via EarthSky.

Lupus is an unassuming constellation whose name means wolf in Latin. The astronomer Ptolemy named Lupus and 47 other constellations in the 2nd century CE. Lupus is boxed in by two larger, brighter and better known constellations: Scorpius and Centaurus.

How to find Lupus the Wolf

Lupus is located south of the ecliptic. If you want to see it, you’ll need to be in the Southern Hemisphere or southward of Florida in the Northern Hemisphere. April through September are the best months to spot Lupus. The Wolf sits beside the constellation Norma the Carpenter’s Square. Scorpius the Scorpion is one of the noticeable constellations that border Lupus, and Centaurus lies on the opposite side.

The stars in Lupus are dim; therefore, you may want to trace out the forms of the Scorpion and Centaur first. Then look toward the dark patch of sky between them. Lupus and Norma both reside here: Lupus has brighter stars and sits farther north than Norma.

Lupus looks vaguely like the wolf it represents. Plus. from the Northern Hemisphere, you may only see the head of the Wolf near Scorpius. From the south, Lupus will be close to overhead on June evenings.

View at EarthSky Community Photos. | Prateek Pandey in Bhopal, India, captured this photo of Lupus and Centaurus on April 18, 2021. He wrote: “The constellation Lupus – its name is Latin for wolf – lies between Scorpius and Centaurus.” Thank you, Prateek!

Stars of the Wolf

The main stars in Lupus are mostly 2nd and 3rd magnitude. The stars near the pincers of Scorpius form a triangle that marks the head of Lupus the Wolf. These stars are Eta Lupi, 440 light-years away, Theta Lupi at a distance of 410 light-years, and Chi Lupi, 470 light-years.

Four stars mark the curve of the Wolf’s body: Gamma Lupi at a distance of 420 light-years, Delta Lupi at 880 light-years and Beta Lupi at 383 light-years. Last is the brightest star in Lupus, magnitude 2.29 Alpha Lupi at a distance of 460 light-years.

Two brighter stars seem to hang down from Beta Lupi and mark the front leg of the wolf. However, these stars are classified as part of Centaurus the Centaur.

If you scan the boundaries of the constellation Lupus with a telescope, you’ll find many double stars and star clusters. Although Lupus is juxtaposed on the Milky Way, it does not have many bright deep-sky observing targets for binocular users.

The stars of Lupus the Wolf. Image via International Astronomical Union/ Sky & Telescope/ Wikimedia Commons (CC BY 3.0).

Bottom line: Lupus the Wolf is a constellation that lies between Scorpius and Centaurus. You have to be farther south on the globe to see the Wolf.

The post Lupus the Wolf, a constellation in southern skies first appeared on EarthSky.

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