Astronomers have just realized that the Milky Way is too big for its surroundings

(ORDO NEWS) — Our home, the Milky Way, doesn’t seem particularly strange in a galaxy. Moderate in size, spiral in shape, with a few curves suggestive of a destructive past.

But astronomers have just revealed a quirk never seen before in any of the galaxies studied to date: the Milky Way is too big for its surroundings.

In particular, it appears to be too large for the area in which it is located, known as the Local Leaf. This flattened arrangement of galaxies has similar velocities bounded by relatively empty space, called voids, on either side.

Our Local sheet is an example of a “cosmological wall” separating the Local Void in one direction from the Southern Void in the other.

The relationships between galaxies on the Local Sheet appear to have a strong influence on their behavior; for example, their close velocities relative to the expansion of the universe. Outside the environment of the cosmological wall, these speeds will have a much wider range.

To determine the influence of the environment on the galaxies around us, a team of astronomers led by Miguel Aragon from the National Autonomous University of Mexico conducted an analysis using simulations from the IllustrisTNG project, which models the physical universe.

They didn’t expect to find anything particularly out of the ordinary.

The Milky Way is special in some way,” says Aragon. “Earth is clearly special, the only house of life known to us. But it is not the center of the universe and not even the solar system.

And the Sun is an ordinary star among the billions of the Milky Way. Even our galaxy seemed to be just another spiral galaxy among billions of others in the observable universe.”

But when they modeled a volume of space about a billion light-years across, containing millions of galaxies, a different picture emerged: that just a small handful of galaxies as massive as the Milky Way could be located inside the cosmological wall.

“The Milky Way has no particular mass or type. There are plenty of spiral galaxies that look something like this,” says astronomer Joe Silk of the Paris Institute of Astrophysics at the Sorbonne in France.

“But this is a rarity, given his environment. If you could see the next dozen or so large galaxies easily in the sky, you would see that they all almost lie on the ring, Nab. added to local sheet. It’s a bit special in itself.

We recently discovered that other walls of galaxies in the universe, such as the Local Leaf, very rarely have a galaxy within them as massive as the Milky Way.”

The team’s analysis left out the account of Andromeda, the Milky Way’s largest galactic neighbor. Also a feature of the Local Leaf – and therefore part of the same cosmological wall – is a galaxy the same size as the Milky Way.

Since the presence of two heavyweights in the cosmological wall would be even rarer, their conclusions still apply.

However, the study highlights that we may need to consider our local environment when exploring the Milky Way, rather than assuming our house hangs on average in an average place in the universe.

Since the team only took into account the context of the Milky Way inside the cosmological wall in their simulations, it is possible that future work could explain the greater number of galaxies in the Local Group.

The researchers also note that environmental context may help explain some previously unexplained phenomena, such as the unusual arrangement of satellite galaxies around Andromeda and the strange absence of them around the Milky Way.

“You really have to be careful… choosing properties that qualify as ‘special’. “says astronomer Marc Neyrink of the Basque Science Foundation in Spain.

“If we were to add a ridiculous restrictive condition to a galaxy, such as that it must contain an article we wrote about it, we would by far be the only galaxy in the observable universe like this.

But we think this ‘too big for its wall’ property makes physical sense and is observationally relevant enough to call it really special.”


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