15 October 2015, 07:00 AM ET
On Oct. 6, 1995, Michel Mayor and Didier Queloz of Switzerland's Geneva Observatory announced the discovery of 51 Pegasi b, the first alien planet ever found around a sunlike star.
14 October 2015, 03:45 PM ET
It's a virtual certainty that comets have delivered the building blocks of life to Europa's hidden ocean, according to a new study.
13 October 2015, 07:33 AM ET
Researchers have created a "habitability index" that allows them to rank alien worlds in terms of their life-hosting potential. The metric could help guide the operations of future observatories that will scan exoplanet atmospheres for signs of life.
09 October 2015, 04:47 PM ET
Hawking recently posited that an alien visitation would put Earthlings in the same position as Native Americans when Columbus landed on their shores. Lessons from Earth suggest intelligence and aggression might evolve hand-in-hand.
09 October 2015, 07:00 AM ET
Although time machines remain a sci-fi fantasy, the vast distances of the universe make it possible to peer back in time and see things as they appeared billions of years ago.
08 October 2015, 02:01 PM ET
A series of freshwater lakes within Mars' 96-mile-wide Gale Crater likely persisted for hundreds or thousands of years at a time, and perhaps even longer, according to the new study, which is based on observations made by NASA's Curiosity rover.
03 October 2015, 09:59 AM ET
There's water on Mars, a resupply spaceship at the International Space Station, a science-heavy survival novel on the big screen and something moving inside Saturn. These are our best space stories of the week.
02 October 2015, 08:54 PM ET
From the discovery of water on Mars to stunning reader images of the Supermoon eclipse, don't miss these amazing space images.
02 October 2015, 07:50 AM ET
A planet with liquid water on the surface and titanium oxide deposited by meteors could produce oxygen in the atmosphere without the need for life.
01 October 2015, 01:16 PM ET
See amazing images of the night sky and cosmos in Space.com's gallery of cosmic images posted in September 2015.
01 October 2015, 07:09 AM ET
Scientists are testing a new microphone technology called the remote acoustic sensor (RAS), which is capable of capturing sounds within extreme and often inaccessible aerospace environments.
29 September 2015, 01:50 PM ET
The twitter account for the upcoming movie "The Martian," due out this Friday (Oct. 2) released a very special video following NASA's announcement of liquid finding water on the surface of Mars.
28 September 2015, 04:19 PM ET
Scientists have found liquid water on Mars — does it mean life can exist there, too?
28 September 2015, 03:53 PM ET
After decades of speculation, scientists now know for sure that liquid, salty water flows on the surface of Mars. See what the discovery means in our infographic.
28 September 2015, 01:01 PM ET
The enigmatic dark streaks called recurring slope lineae (RSL) that appear seasonally on steep, relatively warm Martian slopes are caused by salty liquid water, researchers said.
25 September 2015, 10:09 AM ET
The majority of people believe that intelligent aliens are out there, and many want to reach out. The survey found that men are more likely to believe in intelligent aliens than are women, and also more likely to say humanity should reach out.
24 September 2015, 03:06 PM ET
Encryption isn't the reason we're missing alien signals, as Edward Snowden has suggested. Scientists searching for alien life are looking for other hallmarks of communication.
23 September 2015, 07:11 AM ET
The dark, fingerlike features that creep down steep Martian slopes in warm weather continue to puzzle scientists, and generate debate about the best ways to investigate the features.
21 September 2015, 06:30 AM ET
Scientists are developing a mission concept that would send a probe flying through the plume created by the 100-odd geysers erupting from the south polar region of Saturn's ice-covered moon Enceladus.
20 September 2015, 04:37 PM ET
Jeff Bezos announced a new home for Blue Origin and NASA astronaut Scott Kelly reflected on having six more months in orbit. This is our roundup of the best space stories of the week, for Sept. 18, 2015.
18 September 2015, 11:06 PM ET
From a partial solar eclipse to a new view of Pluto, don't miss these amazing space images.
18 September 2015, 07:52 AM ET
Galaxies in the local universe show no signs of advanced alien civilizations — for now.
17 September 2015, 07:31 AM ET
The Square Kilometer Array (SKA), currently planned to begin construction in 2018, could enable the search for intelligent life to piggy-back on other scientific observations, scouring the galaxy with unprecedented precision.
16 September 2015, 09:43 PM ET
14 September 2015, 02:00 PM ET
Something strange is happening on Io: The Jupiter moon's vigorous volcanoes are mysteriously offset from where scientists expected, and its underground magma oceans may be the cause.
13 September 2015, 02:37 AM ET
NASA's New Horizons spacecraft beamed home incredible new images of Pluto, scientists found a giant buried ice sheet on Mars and Elon Musk chatted with Stephen Colbert about the future of spaceflight. Here are Space.com's top stories of the week.
10 September 2015, 09:00 AM ET
The "Red Dragon" sample-return mission would grab samples collected by NASA's 2020 Mars rover and send them rocketing back toward Earth, where researchers could scrutinize the material for possible signs of past Red Planet life.
08 September 2015, 07:00 AM ET
While the main thrust of the Europa mission, which NASA aims to launch by the mid-2020s, involves characterizing the icy satellite from afar during dozens of flybys, the space agency is considering sending a small probe down to the surface as well.
02 September 2015, 07:00 AM ET
Light glinting off the ocean of a faraway alien world could help scientists identify potentially habitable exoplanets.
01 September 2015, 07:53 AM ET
Researchers are testing designs for a starshade, which whould block the light from a star while allowing emissions from much dimmer orbiting planets to be spotted by a future space-based telescope.
01 September 2015, 12:00 AM ET
See amazing images of the night sky and cosmos in Space.com's gallery of cosmic images posted in August 2015.
31 August 2015, 07:00 AM ET
NASA already plans to launch a spacecraft to the Jupiter moon Europa in the early to mid-2020s, and it's also mulling a mission to the Saturn satellite Enceladus that would lift off by the end of 2021.