Galaxies

Astronomers estimate 4.5 billion Earth-like planets are spread throughout the Galaxy

The solar system's moons may have emerged from long-gone planetary baubles

Scientific American contributing editor George Musser answers viewer questions submitted to YouTube's Spacelab Channel

Scientists have found evidence of polar lights on exoplanets and hope the discovery will add insight as to the strength of a planet's magnetic field

Recent findings back up Einstein's thinking and cast doubt on "rolling scalar fields," an alternative theory of dark energy that suggests the accelerated expansion of the universe will change over time

Kepler space telescope astrophysicist Martin Still looks for Earth-like worlds and tracks the death of stars as he ponders the possible demise of his own program

If a new hypothesis about black hole firewalls proves correct, at least one of three cherished notions in theoretical physics must be wrong.

The latest finds from Hubble date to just a few hundred million years after the big bang

Gamma rays emitted during the formation of neutron stars and black holes allow scientists to study fundamental principles like superstring theory

The Geminid Meteor Shower offers stargazers a host of slow, bright fireballs and lasts for two to three days

Scientists speculate that an energetic "kick" could boot a star out of orbit and drive the remaining pair closer together

Hubble observations of a speedy galaxy weigh on the Milky Way and indicate that our galaxy is at least a trillion times as massive as the sun