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Milky Way found to be too big for its ‘cosmological wall’

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Milky Way found to be more unique than previously thought
A lonely Milky Way Analogue galaxy, too massive for its wall. The background image shows the distribution of dark matter (green and blue) and galaxies (here seen as tiny yellow dots) in a thin slice of the cubic volume in which we expect to find one of such rare massive galaxies. Credit: Images: Miguel A. Aragon-Calvo. Simulation data: Illustris TNG project

Is the Milky Way special, or, at least, is it in a special place in the universe? An international team of astronomers has found that the answer to that question is yes, in a way not previously appreciated. A new study shows that the Milky Way is too big for its “cosmological wall,” something yet to be seen in other galaxies. The new research is published in Monthly Notices of the Royal Astronomical Society.

A cosmological wall is a flattened arrangement of galaxies found surrounding other galaxies, characterized by particularly empty regions called “voids” on either side of it. These voids seem to squash the galaxies together into a pancake-like shape to make the flattened arrangement. This wall environment, in this case called the Local Sheet, influences how the Milky Way and rotate around their axes, in a more organized way than if we were in a random place in the universe, without a wall.

Typically, galaxies tend to be significantly smaller than this so-called wall. The Milky Way is found to be surprisingly massive in comparison to its cosmological wall, a rare cosmic occurrence.

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The new findings are based on a state-of-the-art computer simulation, part of the IllustrisTNG project. The team simulated a volume of the universe nearly a billion light-years across that contains millions of galaxies. Only a handful—about a millionth of all the galaxies in the simulation—were as “special” as the Milky Way, i.e., both embedded in a cosmological wall like the Local Sheet, and as massive as our home galaxy.

According to the team, it may be necessary to take into account the special environment around the Milky Way when running simulations, to avoid a so-called “Copernican bias” in making scientific inference from the galaxies around us. This bias, describing the successive removal of our special status in the nearly 500 years since Copernicus demoted the Earth from being at the center of the cosmos, would come from assuming that we reside in a completely average place in the universe. To simulate observations, astronomers sometimes assume that any point in a simulation such as IllustrisTNG is as good as any, but the team’s findings indicate that it may be important to use precise locations to make such measurements.

“So the Milky Way is, in a way, special,” said research lead Miguel Aragón. “The Earth is very obviously special, the only home of life that we know. But it’s not the center of the universe, or even the solar system. And the sun is just an ordinary star among billions in the Milky Way. Even our galaxy seemed to be just another among billions of others in the .”

“The Milky Way doesn’t have a particularly special mass, or type. There are lots of spiral galaxies that look roughly like it,” Joe Silk, another of the researchers, said. “But it is rare if you take into account its surroundings. If you could see the nearest dozen or so large galaxies easily in the sky, you would see that they all nearly lie on a ring, embedded in the Local Sheet. That’s a little bit special in itself. What we newly found is that other walls of galaxies in the universe like the Local Sheet very seldom seem to have a galaxy inside them that’s as massive as the Milky Way.”

“You might have to travel a half a billion from the Milky Way, past many, many , to find another cosmological wall with a galaxy like ours,” Aragón said. He adds, “That’s a couple of hundred times farther away than the nearest large galaxy around us, Andromeda.”

“You do have to be careful, though, choosing properties that qualify as ‘special,'” Neyrinck, another member of the team, said. “If we added a ridiculously restrictive condition on a galaxy, such as that it must contain the paper we wrote about this, we would certainly be the only galaxy in the observable like that. But we think this ‘too big for its wall’ property is physically meaningful and observationally relevant enough to call out as really being special.”

More information:
M A Aragon-Calvo et al, The unusual Milky Way-local sheet system: implications for spin strength and alignment, Monthly Notices of the Royal Astronomical Society: Letters (2022). DOI: 10.1093/mnrasl/slac161

Citation:
Milky Way found to be too big for its ‘cosmological wall’ (2023, January 23)
retrieved 23 January 2023
from https://phys.org/news/2023-01-milky-big-cosmological-wall.html

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Eta Aquariids meteor shower: Fireball streaks across BC sky

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A bright green fireball streaked across the Okanagan sky Wednesday night, and sightings were reported elsewhere in southern B.C.

The exciting celestial event occurred just before 10 p.m. Wednesday and residents across Kelowna, Kamloops and down to Osoyoos reported seeing the fireball.

One Castanet reader who lives near Kelowna International Airport said it appeared in the sky to the west.

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“It didn’t have a fast movement to it, it sort of came flowing down,” he said. “It was a very bright green, beautiful orb, just very strange, that fell out of the sky last night.”

Kamloops resident Justin Moss caught the event on his house’s surveillance camera, pointing south towards the TRU campus.

People living on Vancouver Island posted online about seeing the event as well, along with others in Washington State.

While it’s not clear what the fireball in the sky was, the Eta Aquariids meteor shower is currently ongoing. The meteor shower, associated with Halley’s Comet, generally runs from about April 19 to May 28 every year, peaking around May 5 or 6.

A meteor’s colour is indicative of the chemical makeup of a meteor. Those with a lot of nickel glow green when they burn up in the earth’s atmosphere.

 

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NASA Contractor Warns That Boeing Launch Must Be Stopped "Before Something Catastrophic Happens"

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“NASA needs to re-double safety checks and re-examine safety protocols to make sure the Starliner is safe before something catastrophic happens to the astronauts and to the people on the ground.”

Shut It Down

A NASA contractor is urging the space agency to suspend the upcoming Boeing Starliner launch over major safety concerns with the aerospace company’s wares.

In a press release, the president of ValveTech, a NASA contractor that supplies the agency with parts, warned that the buzzing sound heard during the now-scrubbed Starliner launch could indicate something seriously wrong with the transport capsule.

“As a valued NASA partner and as valve experts, we strongly urge them not to attempt a second launch due to the risk of a disaster occurring on the launchpad,” ValveTech president Erin Faville cautioned. “According to media reports, a buzzing sound indicating the leaking valve was noticed by someone walking by the Starliner minutes before launch. This sound could indicate that the valve has passed its lifecycle.”

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After the incident, which occurred just before Starliner was supposed to attempt its first crewed launch earlier in May, NASA has said that it won’t try again until at least May 17. According to Faville, much needs to be be done between now and then to head off the worst possible outcomes.

“NASA needs to re-double safety checks and re-examine safety protocols,” he said, “to make sure the Starliner is safe before something catastrophic happens to the astronauts and to the people on the ground.”

Bad News Boeing

The CEO of United Launch Alliance, which is launching the craft into orbit, pushed back strongly on X-formerly-Twitter.

“Not sure what to say about this one,” he wrote. “Close to none of it is correct: Not urgent. Not leaking. Etc. Remarkable that the particular person quoted doesn’t seem to know how this type of valve works.”

ValveTech’s warnings come not just after the scrubbed Starliner launch, but also after months of terrible press for Boeing that have included parts falling off its planes, government investigations, and two dead whistleblowers.

As the company’s press release notes, the launch scrub also occurred after a November 2023 ruling in which a federal court found that Boeing had used a valve from another aerospace company, Aerojet Rocketdyne, that copied ValveTech’s designs. The part was not, according to a witness in that trial, equipped for the job it was meant to do, and as far as the company can tell, it hasn’t been replaced.

“ValveTech continues to question how NASA, Boeing and Aerojet could have qualified this valve for the mission without proper supporting data or previous history or legacy information, which in its experience, goes against aerospace-industry qualification protocols established by NASA,” the press release reads.

All told, these are some pretty serious claims, and Futurism has reached out to NASA to ask if the parts in question have been replaced.

 

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Strong solar storm could trigger northern lights in United States

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Multiple outbursts from the sun could trigger magnificent auroras in many parts of the United States this weekend.

A severe geomagnetic storm is expected to hit Earth on Friday, triggering colorful nighttime auroras, or the northern lights. People in the United States could see moderate to strong geomagnetic activity starting around 11 p.m. and lasting through Saturday.

 

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