The supermassive black hole that lives at the center of our galaxy has been mysteriously sparkling as of late, and nobody knows the reason.
This dark behemoth, known as as Sagittarius A* (Sgr A*), is four million times as massive as the Sun. Though no light escapes its boundaries, astronomers can observe the hole’s interactions with bright stars or dust clouds that surround it.
Back in early January, when scientists pulled down their first batch of data from the New Horizons spacecraft, they celebrated an odd snowman-shaped object in the outer Solar System. From this first look, it appeared as though Ultima Thule, formally named 2014 MU69, consisted of two spheres in contact with one another—a contact binary.
Two newfound galaxies appear to be devoid of the substance, paradoxically providing more proof dark matter exists
Much as a ripple in a pond reveals a thrown stone, the existence of the mysterious stuff known as dark matter is inferred via its wider cosmic influence. Astronomers cannot see it directly, but its gravity sculpts the birth, shape and movement of galaxies. This makes a discovery from last year all the more unexpected: a weirdly diffuse galaxy that seemed to harbor no dark matter at all.
Two astronomers have devised a method that lets them “see” dark matter with the light from rogue stars. The pair has shown how images of faint starlight taken with the Hubble Space Telescope can be used to map dark matter’s distribution in galaxy clusters. The novel technique could ultimately help explore the nature of dark matter.
The human tolerance for sound is, on a galactic level, puny. Volcano eruptions, jackhammer-intensive construction work, My Bloody Valentine concerts—these tinnitus-inducing phenomena are barely whispers besides the majestic, roiling bursts and collisions going on in outer space.
Of course, much of this activity is technically soundless—space’s atmosphere lacks the material that make sound waves possible. So for this week’s Giz Asks, we asked experts in astronomy and astrophysics what the loudest sound wouldbe, if sound as we understand it existed up there.