Dark energy is an unknown form of energy which is hypothesized to permeate all of space, tending to accelerate the expansion of the universe.

Einstein's theory of general relativity was not always considered correct. It wasn't until Hubble made a grand discovery that the equation was fixed.... or was it? Some scientists believe the equation should actually go back to it's original form due to dark energy.

Evidence suggests that the so called "habitable zone" changes as the Sun ages. Many years ago, Venus may have resembled Earth and been home to life.

Evidence shows that the Andromeda Galaxy is headed straight for our own. In the next few billion years, the two will collide. The Solar System will most likely be okay though.

By studying similar stars, scientists believe they can predict what will happen to our Sun over time. One prediction is that the sun will get brighter as it ages.

Is an ocean actually critical for life to survive? Does that ocean have to be made of water?

Photos from a zone on Mars called the Newton Crater are helping to shed light on the amount of water left on the planet. The moisture left is extremely salty, and possibly toxic to life forms.

Methane is the primary ingredient in many of Saturn's moon's lakes and seas. Scientists designed a submarine that can withstand the volatile chemicals that will be found in these methane lakes.

After Voyager 2 left Saturn, scientists noticed something wrong with the space probe's camera. To fix it from Earth, over a billion miles away, they had to come up with a creative solution.

The Family Portrait is an image of the Solar System acquired by Voyager 1 on February 14, 1990 from a distance of approximately 6 billion kilometers from Earth.

According to current quantum theory, particles can spontaneously appear from nowhere. Since matter and antimatter are opposites, they cancel each other out almost instantly when they come in contact..but how are they influenced by external magnetic fields

Ion thrusters create small thrust levels in comparison to conventional chemical rockets, but achieve high specific impulse. They could be practical in the vacuum of space.

Jupiter’s Great Red Spot – the largest and longest-running storm in our solar system – is shrinking. Juan Lora, a planetary scientist at UCLA, explains why.

Gravity from Jupiter and three neighboring moons twist Io's core, resulting in massive eruptions.

Instead of lava, freezing water is believed to burst from Wright Mons on Pluto.

Volcanic activity on Io, one of Jupiter’s moons, could be the key to the planet’s extraordinary auroras. Here’s how scientists at Syracuse University in New York have recreated volcanic activity on Io.

After Voyager 2 left Saturn, scientists noticed something wrong with the space probe's camera. To fix it from Earth, over a billion miles away, they had to come up with a creative solution.

The Family Portrait is an image of the Solar System acquired by Voyager 1 on February 14, 1990 from a distance of approximately 6 billion kilometers from Earth.

Astronomers find a pulsar feeding off the gas of a nearby star.

Ion thrusters create small thrust levels in comparison to conventional chemical rockets, but achieve high specific impulse. They could be practical in the vacuum of space.

Watch how these trillion-year stars "throw tantrums".

According to current quantum theory, particles can spontaneously appear from nowhere. Since matter and antimatter are opposites, they cancel each other out almost instantly when they come in contact..but how are they influenced by external magnetic fields

The Arecibo Message was a radio signal sent into space with information about Earth in the hope that alien intelligence could understand it -- and respond.

A Dyson sphere is a theoretical mega-structure that could only be built by an advanced civilization. Have astronomers discovered one?

Astronomers combine visible light, infrared light, ultraviolet light, X-rays, and radio waves for a dazzling image.

Even this small asteroid which burned up in the atmosphere still destroyed property and injured 1,500 people.

Should our first off-world colony be in orbit, on the moon, or on Mars?

Explore one of the first planets discovered in another star's habitable zone.

Explore one of the first planets discovered in another star's habitable zone.

Scientists at the National Ignition Facility use lasers to create tiny fusion reactions, like those found in the sun.

Liquid water flows intermittently on the surface of Mars. In those streams, microbial life may have managed to arise.

Dr. Alan Guth unveils the theory of inflation.