Explore astronomy, from the latest trip to the International Space Station to alien planets outside our solar system.
Video: Just how big is Earth in comparison to the Sun, stars and other planets?
The fourth planet from the sun, Mars is one of our closest neighbors in the solar system, and yet it remains a mystery.
Video: An airport in inner Mongolia reportedly shut down due to UFO sightings.
Some astrophysicists propose time will end in 5 billion years with an event no creature alive will witness.
Physicists have calculated that time is likely to end within the next 4 billion years due to a catastrophe that no one alive at the time will witness.
Video: Former U.S. Air Force personnel claim they experienced UFO activity near nuclear sites at which they worked.
First contact will be made by Malaysian astrophysicist.
Humanity’s move into space has been called mankind’s greatest adventure. Certainly, it can be considered one of the most dramatic and triumphant.
Some insist a mysterious photograph shows machinery on Mars despite complete lack of credible evidence.
Video: Leslie Kean describes the hard evidence of UFOs and calls for more investigation into them. Plus: Did you know there was a UFO at Chicago's O'Hare Airport?
Scientists reconstruct a story of cataclysmic violence in the Southwest.
Proposed telescope will look for habitable exoplanets and study the nature of dark energy.
Video: MSNBC's Chris Jansing talks with NASA astronauts Mark and Scott Kelly, who will become the first identical twins in space at the same time.
Experts think Van Gogh and Bach would be more appealing than Newton or Einstein.
Robonaut 2 is scheduled to arrive at the International Space Station in November, fields Twitter questions in the meantime.
Activist and author blogs about politics, energy and Earth's resources.
Science journalist blogs about humans and other wildlife.