Planets that could support life:

All life on Earth needs water, so that is the main thing that a planet would need to have in order to support life. Another important thing would be an atmosphere. The planet would also have to be the right distance from the sun so it wasn't too hot or too cold.

In our Solar System, Mars is a planet that may once have supported life. There may have once been water on Mars. It could still contain life. Two robots are already on Mars, searching for evidence of water.

Although astronomers have found more than 100 planets around other stars, none of them are like Earth, and none could sustain life as we know it. One of the planets orbits the star 91 Aquarius, 146 light-years away. It is a gas giant that is three times larger than Jupiter. Another planet that is 299 light-years away, is 6 times larger than Jupiter.

For the first time, scientists have found oxygen and carbon in the atmosphere of a planet beyond our Solar System. The planet is named HD 209458b. It is another "hot Jupiter," and is 150 light-years from Earth in the constellation Pegasus.

Recently, scientists discovered that the Vega star has a group of planets orbiting it that are probably similar to our own Solar System. One of them may be similar to Earth! Vega is 25 light-years from Earth. Now, if we could just get there!

Distance to other solar systems:

The nearest star to our Solar System is called Proxima Centauri. Proxima Centauri is just a star, with no planets around it. It would take over 4.2 light years to gets there if you could travel at the speed of light.

One of the fastest spacecraft, called the Voyager, can travel up to speeds of up to 37,000 miles per hour. It would take 80,000 years to get to Proxima Centauri.

Hmm, looks like we're going to have to speed things up a bit . . .

Speed of Travel:

The speed of light is always the same (specifically, 300000 km/s). According to the scientist Albert Einstein, it is impossible for anything with mass, like a spaceship, to reach the speed of light. Experiments have shown that as you travel faster and approach the speed of light, distances shorten and time slows down so that light still travels at 300000 km/s relative to you. In other words, you can never catch up to light.

Scientists have discovered an Interplanetary Superhighway in space! The highway is made of connecting tube-like areas between the planets and stars where the gravity cancels each other out. This leaves paths through the gravity fields that spacecraft can travel on, increasing their speed, and reducing the amount of fuel they need. NASA scientists plan to map out these tubes for the whole solar system.

Images of space on this page are Courtesy of NASA/JPL-Caltech