Free-floating stars in the Milky Way's bulge

The path of a light beam is bent by the presence of mass, as explained by General Relativity. A massive body can therefore act like a lens—a so called "gravitational lens"—to distort the image of an object seen behind ...

How to weigh stars with gravitational lensing

Astronomy & Astrophysics publishes the predictions of the passages of foreground stars in front of background stars. A team of astronomers, using ultra-precise measurements from the Gaia satellite, have accurately forecast ...

Is dark matter made of primordial black holes?

Astronomers studying the motions of galaxies and the character of the cosmic microwave background radiation came to realize in the last century that most of the matter in the universe was not visible. About 84 percent of ...

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