Q How many galaxies are in the universe? — Gus Powvens, Madison, Wis. A Jim Lattis, director of the UW Space Place at the University of Wisconsin-Madison: Galaxies are clouds of stars that range in ...

For decades, scientists engaged in the Search for Extraterrestrial Intelligence (SETI) have probed the galaxy for signs of ...

“We see at most 3% of the universe,” said Pamela Gay of the Planetary Science Institute, citing a mind-boggling constraint that envelops each effort to respond to one of astronomy’s most venerable ...

Dark matter plays a crucial role in galaxy formation by acting as a gravitational “glue” that helps pull gas together to form ...

In space, the gravitational pull of massive objects is irresistible to smaller ones. Moons are locked in orbit around planets. Planets, asteroids and comets orbit more massive stars, and stars collect ...

Astronomers use many methods to determine this number, including gravitational lensing, the universe’s expansion rate, and more.

Galaxies are clouds of stars that range in both size and composition. Some contain hundreds of millions of stars while the largest galaxies can contain trillions of stars. And while it’s not entirely ...