Connect with us

In their pursuit of understanding cosmic evolution, scientists rely on a two-pronged approach. Using advanced instruments, astronomical surveys attempt to look farther and farther into space (and back in time) to study the earliest periods of the Universe. At the same time, scientists create simulations that attempt to model how the Universe has evolved based on our understanding of physics. When the two match, astrophysicists and cosmologists know they are on the right track!

In recent years, increasingly-detailed simulations have been made using increasingly sophisticated supercomputers, which have yielded increasingly accurate results. Recently, an international team of researchers led by the University of Helsinki conducted the most accurate simulations to date. Known as SIBELIUS-DARK, these simulations accurately predicted the evolution of our corner of the cosmos from the Big Bang to the present day.

In addition to the University of Helsinki, the team was comprised of researchers from the Institute for Computational Cosmology (ICC) and the Centre for Extragalactic Astronomy at Durham University, the Lorentz Institute for Theoretical Physics at Leiden University, the Institut d’Astrophysique de Paris, and The Oskar Klein Centre at Stockholm University. The team’s results are published in the Monthly Notices of the Royal Astronomical Society.

Kuva1 drupal 1 1024x556 2
Images of the SIBELIUS-DARK simulation. Credit: McAlpine et al. (2021)

This simulation is the first study conducted as part of the “Simulations Beyond the Local Universe” (SIBELIUS) project and was performed using the DiRAC COSmology MAchine (COSMA), a distributed computer network operated by the ICC. The simulation covers a volume of space up to a distance of 600 million light-years from Earth and is represented by over 130 billion simulated ‘particles’, which required thousands of computers several weeks to produce.

The team used known physics to describe how Dark Matter and cosmic gas evolved during the history of the Universe. Specifically, they sought to determine if what we observe today is consistent with the standard model of cosmology – the Cold Dark Matter (CDM) model. For the past few decades, astrophysicists have used this model to explain the properties of the Cosmic Microwave Background (CMB) to the number and spatial distribution of the galaxies we see today.

Previous CDM simulations have typically modeled random patches of the Universe that are similar to what we observe today. By using advanced generative algorithms, these simulations were conditioned to reproduce our specific patch of the Universe. This allowed the team to see if their simulation reproduced the present-day structures in the vicinity of the Milky Way that astronomers have observed for decades.

After meticulously comparing the virtual Universe they created to a series of observational surveys, they found that the simulation matched the locations and properties of structures like the Virgo, Coma, and Perseus galaxy clusters, the “Great Wall,” and the “Local Void.” Most importantly, at the center of the simulation were the two most important and familiar structures to astronomers: the virtual counterparts of the Milky Way and the neighboring Andromeda galaxy.

The Local Environment 1024x354 1
At the very center of the simulation is the Milky Way galaxy (MW) and our nearest massive neighbour, the Andromeda galaxy (M31). Credit Dr Stuart McAlpine

As co-author Professor Carlos Frenk (the Ogden Professor

Frontier Adventure

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
Did you miss our previous article…
https://mansbrand.com/neutron-star-is-spraying-jets-like-a-garden-sprinkler/

Continue Reading

Frontier Adventure

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…
https://mansbrand.com/experimental-radar-technique-reveals-the-composition-of-titans-seas/

Continue Reading

Frontier Adventure

Experimental Radar Technique Reveals the Composition of Titan’s Seas

Cassini Titan bistatic schematic 1024x523 1

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
Did you miss our previous article…
https://mansbrand.com/webb-measures-the-weather-on-a-tidally-locked-exoplanet/

Continue Reading

Trending