Milky Way tagged posts

Dark matter may come in two flavors—finally explaining why its signals appear in some galaxies but vanish in others. A mysterious glow of gamma rays at the center of the Milky Way has long hinted at dark matter, but the lack of similar signals in smaller dwarf galaxies has cast doubt on that idea. Now, researchers propose a bold twist: dark matter might not be a single particle at all, but a mix of two different types that must interact with each other to produce detectable signals.

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Giant black holes may be secretly controlling how entire clusters of galaxies grow. A blazing supermassive black hole can influence far more than its own galaxy. Scientists found that quasars emit radiation strong enough to shut down star formation in nearby galaxies millions of light-years away. This could explain why some galaxies near early quasars appear faint or missing. The finding suggests galaxies grow and evolve together, not in isolation.

Powerful radiation from active supermassive black holes, which are believed to sit at the center of most galaxies, can do more than shape their own surroundings. A new study led by Yongda Zhu at the University of Arizona suggests these black holes can also slow the formation of stars in galaxies located millions of light-years away.

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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...

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 ...