Home / Science / Meet our neighbors, the local emptiness. Look inside, Puny Humans.

Meet our neighbors, the local emptiness. Look inside, Puny Humans.

Our planet is part of the larger structure of the solar system, which is shaped and stabilized by gravity. Our solar system, along with hundreds of millions of other solar systems, is gravitationally bound to the Milky Way. And our galaxy is also part of a larger structure in which not only gravity but also the expansion of the universe shapes and shapes this structure. This is nothing new to the readers of Universe Today.

A new study now sheds light on a strange part of our cosmic neighborhood where there is basically nothing: the local emptiness.

Galaxies are not evenly distributed throughout the universe. They form filaments and lumps throughout the room. Our Milky Way galaxy is part of a group of galaxies called a local group. The local group is dominated by the Milky Way and its larger sibling, the Andromeda galaxy. The many dwarf galaxies gravitationally attached to the Milky Way and Andromeda complete the local population. The local group itself is part of an even larger structure called the Laniakea Super Cluster, which contains over 1

00,000 galaxies.

On the edge of our own galaxy is an area of ​​nothing known as the Local Void. The local emptiness is part of the huge cosmic structure in our neighborhood, a region without galaxies (almost). Scientists want to know more about our galactic neighborhood, and a new study published in the Astronomical Journal maps the extent of the local void.

Our Milky Way is not only part of the local galaxy group, but also part of the so-called Local Sheet. The Local Sheet is a flat array of galaxies adjacent to the Local Void. The Local Sheet contains not only the Milky Way, but also other members of the Local Group and some other galaxies. The Milky Way moves along with the rest of the local layer at 260 km / s away from the void.

All matter is attracted to other matter by gravity. For this reason, we see filament structures and lump structures in the large-format map of the universe. That is also the reason why there are gaps. Once a void begins, there is nothing left that could attract anything, and the void grows. In fact, if you randomly pick a point in the universe, chances are you'll pick a void. Nothing is more common than something.

  The millennium simulation created this image of the large-scale structure of the universe, showing filaments and voids within the cosmic structure. According to a recent study by the University of Wisconsin, our Milky Way is in a vast void in the cosmic structure. The Millennium Simulation is a project of the Max Planck High Performance Computing Center in Germany. Image: Millennium Simulation Project
Image of the large-scale structure of the universe with filaments and cavities within the cosmic structure. Credit: Millennium Simulation Project

The new study is entitled "Cosmicflows-3: Cosmography of the Local Void". Cosmicflows-3 is a compendium of over 17,000 galaxy distances in our cosmic neighborhood, creating a new, updated map of the vast local void. It's the third edition of the compendium, and every new issue is more thorough than the last one.

As gravity moves galaxies toward each other, gaps open up. The local void is of particular interest to scientists because the matter that makes up the Milky Way and the rest of the local group is probably from the local void. The study of these gaps should also tell us something about dark matter. The local emptiness is hard to study as it is located behind the central mass of the Milky Way and blocks the view.

  Local group of galaxies, including the massive members M31 (Andromeda Galaxy) and Milky Way, as well as other nearby galaxies. Photo credits: Wikipedia Commons / Antonio Ciccolella
Local group of galaxies, including the massive members M31 (Andromeda Galaxy) and Milky Way, as well as other nearby galaxies. Image credits: Wikipedia Commons / Antonio Ciccolella

The lead author of this new study is R. Brent Tully of the University of Hawaii Institute of Astronomy (IfA) Tully and the rest of the team responsible for the study got around this obstacle by observing galaxy movements and subsequent conclusion of the mass distribution responsible for the movement.

This movement is not only based on gravity, but also on the expansion of the universe. The team behind the study uses the movement of galaxies to not only derive the mass distribution, but also to create three-dimensional maps of our neighborhood to the universe.

They used this data to create a cosmographic map that highlights the boundary between the collection of matter and the absence of matter that defines the edge of the local void. This is the same technique that Tully and other scientists used in 2014 identified the full extent of our Home Superpeapple of over one hundred thousand galaxies. (They called it Laniakea, which in Hawaiian means "immense sky.")

The following video explains the study's findings as well as the shape and shape of the local emptiness and the surrounding structures.

Excuse the machine voice, but this video explains the results of the study. Photo credit: R. Tully / Department of Astronomy, University of Hawaii (IfA) Give it a try.

What is the conclusion?

Already in 2007, Tully discovered that the void is expanding. This was due to the presence of a dwarf galaxy in the void. It also showed how big the gap is. The dwarf galaxy fled with 350 km / s from the void. This means that the local void must be huge and must have a diameter of at least 150 million light years. For the faster the dwarf moves, the weaker the gravity of the void must be, which means that it must be bigger.

For the past three decades, astronomers have tried to understand the movements of the Milky Way, our next major galaxy neighbor Andromeda and their smaller neighbors. They all deviate from the total extent of the universe by more than 600 km / s. This new study shows that about half of this movement occurs "locally" from the combination of a move from the massive nearby Virgin Cluster and our involvement in expanding the local void as it becomes increasingly emptier.

Living next to a void of 150 million light-years may sound disturbing. All the nothing, so close. But that's the way it is.

It's not like we're sucked into the void. In fact, the opposite is the case. The lack of matter in the void means a lack of gravity and we slowly move away from the center of the void, in our position with the other galaxies on the local leaf.

But it is there. It means something in the ongoing design of the universe and can tell us something about how the Milky Way originated. Stay tuned.


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