Planets

Earth

Asteroids boiled young Earth’s oceans

At least two asteroids hit Earth 3.3 billion years ago. This superheated the atmosphere, boiled the oceans and shaped how early life evolved.

Planets

Mini-sats: The trick to spying Earth-bound asteroids?

NASA is supposed to begin nonstop screening by 2020 for all asteroids that could pose a threat to Earth. Some astronomers now think the only way to affordably meet that deadline is by using mini-satellites

Planets

Something’s cooking on Saturn’s moon

Grit in one of Saturn’s rings likely formed in hot water on the planet’s ice-covered moon Enceladus. That suggests conditions on this moon might be able to support life.

Chemistry

Asteroid impacts may have sparked life on Earth

The energy produced by comets and asteroids that collide with Earth may have been strong enough to start life.

Planets

Comet probe may shed light on Earth’s past

Scientists spent more than two decades setting up Philae’s months-long investigation of a comet. What they hope to learn could shed light on Earth’s childhood — and the source of its water. But that’s if problems with Philae’s landing don’t cut the robot’s life span.

Planets

Picture This: Falling to a comet

After a more than decade-long ride, a robotic lander has left its spacecraft and floated down onto the surface of a comet. From there it should begin scouting for hints at how our solar system formed.

Planets

Distant world hosts water

One measure of an extraterrestrial world’s potential for supporting life is the presence of water. The Neptune-size HAT-P-11b fits that criterion.

Planets

This moon’s surface slides, just like Earth’s

Europa is one of Jupiter’s giant, icy moons. Scientists say it has plate tectonics, which means its surface is covered by moving, giant slabs.

Planets

Asteroids: A stepping stone to Mars?

NASA's Asteroid Redirect Mission, designed to capture and move an asteroid, may be a step toward getting to Mars. But not everyone agrees it's the right step.

Planets

Asteroids: Avoiding an Earthly smashup

Any of nearly 1,500 asteroids could hit Earth. Experts want to learn more about the space rocks — and maybe even bump them off course.

Planets

Explainer: What are asteroids?

Leftovers from the creation of the solar system, asteroids are space rocks that orbit the sun. Let’s hope the big ones never become meteorites.

Earth

Meteorites likely wiped out Earth’s earliest life

Enormous meteorites appear to have slammed into Earth several times early in its history. Each mega-smashup would have boiled off oceans and obliterated any bit of life.