Space

Explore the vast reaches of space and mankind’s continuing efforts to conquer the stars, including theories such as the Big Bang, the International Space Station, plus what the future holds for space travel and exploration.


The smallest and most-distant planet in our solar system is tiny, icy Pluto. It is even smaller than our moon, and wasn't discovered until 1930 — the only planet discovered in the twentieth century.

Mercury is the closest planet to the sun, and it is the second smallest. It is the fastest-moving planet, so it was named after the Roman god of speed. Like Earth, it is a terrestrial planet, meaning it has a solid surface that you could land on.

Our planet Earth is part of a solar system that consists of nine (and possibly ten) planets orbiting a giant, fiery star we call the sun. For thousands of years, astronomers studying the solar system have noticed that these planets march across the sky in a predictable way.

Neptune is the eighth planet from the sun, the fourth largest, and a gas planet. It is named after the Roman god of the sea. Neptune is four times the size of Earth, and its day lasts a little more than16 hours. Its year is about 165 Earth years. Neptune's orbit is a perfect circle. The last stop on spacecraft Voyager's epic trip through the solar system was the gas giant Neptune.

Uranus is the seventh planet from the sun, and is named for the ancient Greek deity of the Heavens, the earliest supreme god. It is the third largest planet in the solar system, and is three times as large as Earth.

Venus is the second planet from the sun, and is about the same size as Earth. It is a terrestrial planet, meaning it has a solid surface. But the harsh conditions on Venus make it very inhospitable. Two spacecraft, Pioneer Venus 1 and Magellan, were able to penetrate the thick atmosphere of this planet.

Saturn is the sixth planet from the sun and the second largest planet in the solar system. It is named for the Roman god of agriculture, one of the most important gods in the Roman world. Saturn is made mostly of hydrogen and helium, and its poles appear to be flattened because of its speedy rotation on its axis...

Saturn is the sixth planet from the sun and the second largest planet in the solar system. It is named for the Roman god of agriculture, one of the most important gods in the Roman world.

Mars, which is the fourth planet from the sun and the third smallest in size, got its name because of its rusty red color. People associated the planet's blood-red color with war, so they named it Mars, after the Roman god of war.

It's bigger, stronger, more efficient and more precise: The Delta IV Heavy is arguably the greatest rocket built to date. It can put 13 tons of satellite payload into its intended orbit with fuel to spare, and that's just the beginning.

The accounts are oddly similar: darting lights in a night sky, a hovering disc, radio interference. How can so many people be "mistaken"? Learn about the evidence for and against alien UFOs and check out some of the stranger tales of contact.

We know who won – top-runner SpaceShipOne. We know what the team receives for that accomplishment: $10 million and an obscenely gigantic trophy. But what about the story behind the contest? Learn about the rules, restrictions, red tape, test crashes, successful launches and the technological innovations that may get you into sub-orbit sooner than you think.

It's launch time for the first privately funded space flight. In the course of battle for the X Prize, a group called Scaled Composites has built and tested SpaceShipOne, a sub-orbital spacecraft intended to carry tourists on the ride of their life. Learn all about the craft.

Of course we want to go to Mars. Until we figure it out though, roving robots with names like Spirit, Opportunity, Sojourner and Curiosity are our best bet for digging up dirt on our nearest planetary neighbor. Want to go along for the ride?

Get a sneak peek (even before NASA scientists) at a new type of spacecraft that could be jolted through space by electromagnets.

Alien life forms would probably differ from those on Earth but still adhere to certain principles. Learn about astrobiology and the search for alien life forms.

Don't worry. We still love you, Earth, but we've been wondering about the possibility of life on other worlds for centuries, and now we have the tools to do some exploring. What have astronomers found so far?

SETI is the Search for Extraterrestrial Intelligence, and it's dedicated to discovering signals sent to Earth from far, far away. Find out what would happen if an extraterrestrial were to make contact.

Project Mercury launched the first American into space. Have a look back at this historic mission.

What is a solar sail? How can you use sunlight to move a spacecraft in outer space? In this article, HowStuffWorks will show you how solar sail technology works, take an in-depth look at the Cosmos-1 mission and find out what solar-sails mean for future space travel.

Scientists are now developing a new type of composite material that will allow spacecraft to repair themselves. Learn more about this amazing future technology.

As the International Space Station astronauts return to Earth after a three-month stay, learn about the effects of weightlessness on the body.

Using current rocket engine technology, a trip to Mars takes seven months. Fusion propulsion would cut that trip in half. Find out what fusion is and how it could speed up space travel.

Like many new technologies, light propulsion was originally conceived as a tool of war and national defense. But the "Star Wars" missile defense system may eventually send rockets, rather than missile-destroying lasers, into space.

I've heard that Russia's Mir station will be brought down out of orbit and crashed to Earth soon. How will they do that?