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Star formation is a topic astronomers are still trying to fully understand. We know, for example, that stars don’t form individually, but rather are born within vast interstellar molecular clouds. These stellar nurseries contain gas dense enough for gravity to trigger the formation of stars. In spiral galaxies, these molecular clouds are most commonly found within spiral arms, which is why stars are most often born in spiral arms.

We can observe several of these molecular clouds in our local neighborhood of the Milky Way. The most famous one is the Orion nebula, which is part of the Orion Molecular Cloud Complex, but there are other well-known molecular clouds, such as the molecular clouds of Perseus and Taurus. We can see stars forming within these clouds.

One part of the story we don’t fully understand is how these dense molecular clouds form in the first place. Since they are often found along spiral arms, one idea is that they form within pressure waves along the arms as stars bunch up like a traffic jam. Another idea is that their formation is triggered by supernovae. These massive explosions create shockwaves in interstellar gas and dust, causing them to bunch together. But proving this idea is hard because it’s extremely difficult to pin down the location of a molecular cloud. We can see where it is in the sky, but determining the distance is difficult. But a new study has pinned down the locations of the Perseus and Taurus clouds, and the result supports the supernova model.

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A bubble exists between the Taurus molecular cloud (blue) and the Perseus molecular cloud (red). Credit: Jasen Lux Chambers/Center for Astrophysics | Harvard & Smithsonian

Using data from the Gaia spacecraft, the team was able to map the Perseus and Taurus molecular clouds in 3-D. They also mapped other, fainter clouds in the region, and found they were all part of a single structure. They all lie along the surface of a bubble about 500 light-years across. The spherical structure is very clear, and the team has even created an augmented reality version you can check out. Based on the structure of the bubble, the team estimates it was formed by a large supernova or series of supernovae that occurred about 10 million years ago. The clouds we see now, and the stars forming within them, are the result of supernova shock waves.

This work shows that supernovae can play a significant role in the formation of stars, beyond their contribution of heavier elements. With 3-D maps such as this one, we can now compare them to simulation models to better understand both cloud formation and star formation.

Reference: Bialy, Shmuel, et al. “The Per-Tau Shell: A Giant Star-forming Spherical Shell Revealed by 3D Dust Observations.” The Astrophysical Journal Letters 919.1 (2021): L5.

The post Astronomers Find a Giant Cavity in Space, Hollowed out by an Ancient Supernova appeared first on Universe Today.

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The First 5 Things I Do in Camp When Backpacking

Tet19 047 Me on Teton Crest Trail copy cropped 38

By Michael Lanza

I doubt that I had any typical routine when arriving at a campsite on my earliest backpacking trips; like many backpackers, I probably just dropped my pack, shucked off my boots, and kicked back until motivated to move by the urge to eat, drink, get warm, or go to the bathroom. Over the years, though, I’ve developed a routine that I follow almost religiously when I arrive in camp at the end of a day of backpacking. These five simple, quick, almost effortless steps make a world of difference in how good I feel that evening and the next morning, and how well I sleep.

These tips derive from habits I’ve gradually adopted over more than three decades and innumerable backpacking trips across the U.S. and around the world, including the 10 years I spent as Northwest Editor of Backpacker magazine and even longer running this blog. These are practices I’ve followed in every type of environment and on every type of trip, from easier outings with my family when our kids were young—although it didn’t always feel “easier” carrying much of our children’s gear and food—to extreme adventures backpacking 20 to 30 or more miles per day.

Tet19 047 Me on Teton Crest Trail copy cropped 39
Hi, I’m Michael Lanza, creator of The Big Outside. Click here to sign up for my FREE email newsletter. Join The Big Outside to get full access to all of my blog’s stories. Click here for my e-books to classic backpacking trips. Click here to learn how I can help you plan your next trip.

A backpacker hiking the Doubletop Mountain Trail, Wind River Range WY.
” data-image-caption=”My wife, Penny, backpacking the Doubletop Mountain Trail in the Wind River Range, Wyoming. Click photo to see “The 10 Best Backpacking Trips in the Wind River Range.”
” data-medium-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/05/06224931/Wind8-014-Penny-Beach-backpacking-the-Doubletop-Mountain-Trail-Wind-River-Range-WY..jpg?fit=300%2C200&ssl=1″ data-large-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/05/06224931/Wind8-014-Penny-Beach-backpacking-the-Doubletop-Mountain-Trail-Wind-River-Range-WY..jpg?fit=900%2C600&ssl=1″ tabindex=”0″ role=”button” src=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/05/06224931/Wind8-014-Penny-Beach-backpacking-the-Doubletop-Mountain-Trail-Wind-River-Range-WY.-1024×683.jpg?resize=900%2C600&ssl=1″ alt=”A backpacker hiking the Doubletop Mountain Trail, Wind River Range WY.” class=”wp-image-58503″ srcset=”https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/05/06224931/Wind8-014-Penny-Beach-backpacking-the-Doubletop-Mountain-Trail-Wind-River-Range-WY..jpg 1024w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/05/06224931/Wind8-014-Penny-Beach-backpacking-the-Doubletop-Mountain-Trail-Wind-River-Range-WY..jpg 300w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/05/06224931/Wind8-014-Penny-Beach-backpacking-the-Doubletop-Mountain-Trail-Wind-River-Range-WY..jpg 768w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/05/06224931/Wind8-014-Penny-Beach-backpacking-the-Doubletop-Mountain-Trail-Wind-River-Range-WY..jpg 150w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/05/06224931/Wind8-014-Penny-Beach-backpacking-the-Doubletop-Mountain-Trail-Wind-River-Range-WY..jpg 1200w” sizes=”(max-width: 900px) 100vw, 900px” data-recalc-dims=”1″ />My wife, Penny, backpacking the Doubletop Mountain Trail in the Wind River Range, Wyoming. Click photo to see “The 10 Best Backpacking Trips in the Wind River Range.”

Follow these tips and I think you’ll make your campsite hours—and backpacking trips as a whole—more comfortable.

Click on any photo to read more about that place and
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Neutron Star is Spraying Jets Like a Garden Sprinkler

Cowie1 s shape jet

X-ray binaries are some of the oddest ducks in the cosmic zoo and they attract attention across thousands of light-years. Now, astronomers have captured new high-resolution radio images of the first one ever discovered. It’s called Circinus X-1. Their views show a weird kind of jet emanating from the neutron star member of the binary. The jet rotates like an off-axis sprinkler as it spews material out through surrounding space, sending shockwaves through the interstellar medium.

The MeerKAT radio telescope in South African spotted the S-shaped jets emanating from the neutron star. Its images are the first-ever high-resolution views of such jets, according to lead researcher Fraser Cowie. “This image is the first time we have seen strong evidence for a precessing jet from a confirmed neutron star,” he said, referring to the neutron star’s off-axis spin. “This evidence comes from both the symmetric S shape of the radio-emitting plasma in the jets and from the fast, wide shockwave, which can only be produced by a jet changing direction.”

Such an awkward spin gives the jets their peculiar S-like configuration. Since scientists aren’t completely sure what phenomena caused them to launch in the first place, studying the odd behavior gives insight into the extreme physics behind its existence.

Examining the Neutron Star Jets in Detail

The MeerKAT measurements showed not only the jet but revealed termination shocks moving away from the neutron star. These occur in regions where the jets slam into material in surrounding space. This is the first time astronomers found such shocks around an X-ray binary like Circinus X-1. Those waves are moving fast—at about 10 percent the speed of light and their structure points back to the jet as their source. “The fact that these shockwaves span a wide angle agrees with our model,” Cowie said. “So we have two strong pieces of evidence telling us the neutron star jet is processing.”

A MeerKAT radio image of the S-shape jet precessing in the Circinus X-1 X-ray binary pair system. The jet emanates as a result of the accretion of material around the neutron star. Courtesy: Fraser Cowie, Attribution CC BY 4.0.
A MeerKAT radio image of the S-shape jet precessing in the Circinus X-1 X-ray binary pair system. The jet emanates as a result of the accretion of material around the neutron star. Courtesy: Fraser Cowie, Attribution CC BY 4.0.

The speed of those shockwaves turns them into particle accelerators producing high-energy cosmic rays. The fact that those rays exist tells astronomers the action around the X-ray binary is extremely energetic. That high-energy activity has grabbed astronomers’ attention for half a century. Still, it remains a mysterious system, so as Cowie points out, it’s important to observe the jets and see how their behavior changes over time. “Several aspects of its behavior are not well explained so it’s very rewarding to help shed new light on this system, building on 50 years of work from others,” he said. “The next steps will be to continue to monitor the jets and see if they change over time in the way we expect. This will allow us to more precisely measure their properties and continue to learn more about this puzzling object.”

bout Circinus X-1

The Circinus X-1 system contains a neutron star and a companion. The pair lies some 30,000 light-years away in the direction of the southern hemisphere constellation Circinus. It was first spotted in June 1969 by an Aerobee suborbital rocket carrying X-ray-sensitive instruments and has been studied for years by astronomers using optical, X-ray, and radio telescopes.

Composite image of Circinus X-1, which is about 24,000 light-years from Earth in the constellation Circinus. Credit: X-ray: NASA/CXC/Univ. of Wisconsin-Madison/S. Heinz et al; Optical: DSS; Radio: Did you miss our previous article…
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Experimental Radar Technique Reveals the Composition of Titan’s Seas

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The Cassini-Huygens mission to Saturn generated so much data that giving it a definitive value is impossible. It’s sufficient to say that the amount is vast and that multiple scientific instruments generated it. One of those instruments was a radar designed to see through Titan’s thick atmosphere and catch a scientific glimpse of the moon’s extraordinary surface.

Scientists are still making new discoveries with all this data.

Though Saturn has almost 150 known moons, Titan attracts almost all of the scientific attention. It’s Saturn’s largest moon and the Solar System’s second largest. But Titan’s surface is what makes it stand out. It’s the only object in the Solar System besides Earth with surface liquids.

Cassini’s radar instrument had two basic modes: active and passive. In active mode, it bounced radio waves off surfaces and measured what was reflected back. In passive mode, it measured waves emitted by Saturn and its moons. Both of these modes are called static modes.

But Cassini had a third mode called bistatic mode that saw more limited use. It was experimental and used its Radio Science Subsystem (RSS) to bounce signals off of Titan’s surface. Instead of travelling back to sensors on the spacecraft, the signals were reflected back to Earth, where they were received at one of NASA’s Deep Space Network (DNS) stations. Critically, after bouncing off of Titan’s surface, the signal was split into two, hence the name bistatic.

A team of researchers has used Cassini’s bistatic data to learn more about Titan’s hydrocarbon seas. Their work, “Surface properties of the seas of Titan as revealed by Cassini mission bistatic radar experiments,” has been published in Nature Communications. Valerio Poggiali, a research associate at the Cornell Center for Astrophysics and Planetary Science, is the lead author.

This schematic shows how Cassini's bistatic radar experiment worked. The orbiter used its Radio Science Subsystem to send signals to Titan's surface. The signals then reflected off of Titan to Earth, where they were received by either the DNS receiver at Canberra, Goldstone, or Madrid. The signals are either Right Circularly Polarized (RCP) or Left Circularly Polarized (LCP.) Image Credit: Poggiali et al. 2024.
This schematic shows how Cassini’s bistatic radar experiment worked. The orbiter used its Radio Science Subsystem to send signals to Titan’s surface. The signals then reflected off Titan to Earth, where they were received by one of the DNS receivers at Canberra, Goldstone, or Madrid. The signals are either Right Circularly Polarized (RCP) or Left Circularly Polarized (LCP). Image Credit: Poggiali et al. 2024.

The signals that reach the DNS are polarized, which reveals more information about the hydrocarbon seas on Titan. While Cassini’s radar instrument revealed how deep the seas are, the bistatic radar data tells researchers about both their compositions and surface textures.

This image of the hydrocarbon seas on Titan is well-known and was radar-imaged by Cassini. That radar data told us how deep the seas are. New bistatic radar data can reveal more about the composition and surface texture of the seas. Image Credit: [JPL-CALTECH/NASA, ASI, USGS]
This image of the hydrocarbon seas on Titan is well-known and was radar-imaged by Cassini. That radar data told us how deep the seas are. New bistatic radar data can reveal more about the composition and surface texture of the seas. Image Credit: [JPL-CALTECH/NASA, ASI, USGS]

“The main difference,” Poggiali said, “is that the bistatic information is
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