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.

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.

Mike explains how you can join the astronaut club.

The NASA probe endures intense radiation to learn Jupiter's secrets

Mike talks about tourism - in space.

Lightning on Jupiter extracts carbon from methane, turning it into diamonds

Mike talks about his favorite memory from orbit.

When astronauts explore Mars, they'll need a way around communication delays of up to 22 minutes.

What formed Orcus Patera? An asteroid, a volcano, or possibly Mars' third moon?

Mike talks about the importance of teamwork.

Mike reveals the moment he thought, “Maybe this wasn’t such a good idea."

Earth and Venus endured massive impacts in the distant past.

Greenhouse gasses from volcanoes have helped raise Venus' surface temperature to 900 degrees Fahrenheit.