Milky Way tagged posts

Milky Way is embedded in a ‘large-scale sheet’ of dark matter, which explains motions of nearby galaxies

The Milky Way is embedded in a 'large-scale sheet' and this explains the motions of nearby galaxies
Various projections of the posterior mean density of the constrained simulation ensemble, normalized by the cosmic mean density. Credit: Nature Astronomy (2026). DOI: 10.1038/s41550-025-02770-w. https://www.nature.com/articles/s41550-025-02770-w

Computer simulations carried out by astronomers from the University of Groningen in collaboration with researchers from Germany, France and Sweden show that most of the (dark) matter beyond the Local Group of galaxies (which includes the Milky Way and the Andromeda galaxy) must be organized in an extended plane. Above and below this plane are large voids. The observed motions of nearby galaxies and the joint masses of the Milky Way and the Andromeda galaxy can only be properly explained with this “flat” mass distribution...

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Astronomers thought the Milky Way was doomed to crash into Andromeda. Now they’re not so sure

A detailed photo of a white-and-pink pinwheel-shaped galaxy.
The new study took into account the gravitational effect of the Triangulum Galaxy, which orbits Andromeda. ESOCC BY

For years, astronomers have predicted a dramatic fate for our galaxy: a head-on collision with Andromeda, our nearest large galactic neighbor. This merger—expected in about 5 billion years—has become a staple of astronomy documentaries, textbooks and popular science writing.

But in our new study published in Nature Astronomy, led by Till Sawala from the University of Helsinki, we find the Milky Way’s future might not be as certain previously assumed.

By carefully accounting for uncertainties in existing measurements, and including the gravitational influence of other nearby galaxies, we found there is only about a 50% chance the Milky Way and Andromeda will ...

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Magnetic fields can map the universe—here’s how

Running Chicken Nebula Credit: ESO

Who knew that magnetic fields could be so useful? Astronomers are able to use magnetic fields to map our environment within the Milky Way using a technique called Faraday rotation.

It works like this. There’s a bunch of dust—literal dust grains—floating within the galaxy.

Well, I say there’s a lot of dust, but it’s at very, very low densities. Thankfully, the volumes within interstellar space are so vast that the total amount of dust can really add up. And all these little dust grains have little magnetic fields associated with them, because all the grains are made of electric charges and they’re spinning around themselves.

When light from distant sources passes through the dust, that light encounters all these little magnetic fields...

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Supermassive Black Hole Heading Towards The Milky Way Galaxy

The strange behavior of hypervelocity stars suggests a nearby dwarf galaxy must contain a supermassive black hole. If so, a collision with the Milky Way is inevitable.

galaxy
(Credit: Alexcpt_photography/Shutterstock)

Back in 1971, a couple of British astronomers predicted the existence of a black hole at the center of our galaxy. And in 1974, other astronomers found it, naming it Sagittarius A*.

Since then, astronomers have discovered that a similar “supermassive black hole” sits at the center of almost every other large galaxy. In 2019, they took the first image of a supermassive black hole. Today, these exotic objects are a fundamental part of our understanding of how galaxies form and evolve.

But what of smaller astronomical bodies, like the Large Magellanic Cloud, a dwarf sa...

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