Ripples found in the Milky Way’s disk reveal our galaxy survived an ancient hit-and-run. Now, astronomers might have caught the culprit.
A cosmic rabbit hole in the tail of Leo will take you to Abell 1367, a wonderland of galaxies more than 300 million light-years from Earth. Step in and lose yourself in the vastness.
Astronomers determine the number of galaxies in the universe by counting up the number visible in a tiny portion of the sky, and then accounting for all the regions of the observable universe. A 2013 study estimates that there are 225 billion galaxies in the observable universe.
Here's how to hone your galaxy-hunting skills — and what to expect at the eyepiece.
Evidence from observations sheds doubt on cosmic cannibalism as a source for galaxy growth, suggesting that instead galaxies grow by pulling in gas from the intergalactic medium.
Astronomers have identified 53 “super spirals” — spiral galaxies that are huge and incredibly luminous — as part of a project exploring archived observations.