Explore astronomy, from the latest trip to the International Space Station to alien planets outside our solar system.
Kelly commanded the space shuttle Endeavour during its last mission into space.
Here's a look at the science behind the summer solstice, the longest day of the year and the official start of summer in the Northern Hemisphere.
The amount of daylight, temperatures and the position of the sun in the sky all change with the solstice.
Storms release plasma across the solar system which can affect the Earth's telecommunication technologies in space.
In reality, the ever-expanding universe is simply too large for the fictional Green Lantern Corps, astronomer says.
Dry ice may be responsible for the comet's peculiar behavior.
The moon took on an eerie red hue Wednesday during the longest total eclipse in 11 years, amazing skywatchers around the world, even in places where the cosmic event wasn't visible.
A monster black hole shredded a Sun-like star, producing a long-lasting flash of gamma rays that probably won't be seen again in a million years.
Volcanoes may have played a large role in Mercury's formation, including its crater-covered landscape and sulfur-rich ground.
Newfound planets are gassy planets of varying mass.
Astronomers have detected faint X-ray signals that they believe were emitted by giant black holes billions of years ago when the universe was young.
Paired stars are discovered when the brightness of one is lessened as its counterpart passes in front of it.
While the eclipse won't be visible in North America, many sources will be streaming the event on the Web.
Scientists thought the Sun would move into solar maximum in 2012, but lately a curious calm has suggested quite the opposite.
Those candidates asked about NASA's future agree that private enterprise is the future of space flight.
Activist and author blogs about politics, energy and Earth's resources.
Science journalist blogs about humans and other wildlife.