The Giant Planets: X-ray Secrets Revealed

NASA: We have booster ignition and liftoff of Columbia, reaching new heights for women and X-ray Astronomy.

Martin Elvis: The main thing Chandra does is take these superb, sharp images.

Narrator: Jupiter and Saturn are the two largest planets in our Solar System, best known for very different reasons. Most people think of Jupiter's famous Great Red Spot, while Saturn is, of course, most loved for those excellent rings. These two planets, however, offer much, much more for astronomers looking to learn more about our Solar System. Dr. Scott Wolk of the Chandra X-ray Center explains why X-ray light can help in this cause.

Scientist: It's hard to imagine x-rays coming from a planet. X-rays are a kind of light we associate with some of the hottest things in the universe, neutron stars, supernova remnants and black holes. If you were to find x-rays coming from a planet, you would think that all the planets would be the same, maybe reflecting x-rays from the Sun. But as we've already seen everywhere else in the universe, things are never that simple. In fact, the stories of Jupiter and Saturn, the two largest planets in the solar system, are completely different.

Narrator: Let's take a look at Saturn first and find out what Chandra has told us so far.

Scientist: Saturn's atmosphere does in fact act like a big massive fuzzy mirror, reflecting X-rays emitted by the Sun back to the Earth, much like it reflects sunlight back to us that we see in the night sky. How are we so certain about this? Well, the Sun flares in x-rays, getting hundreds of times brighter, and the Sun flared during one of the Chandra observations of Saturn. Two hours and 14 minutes later, exactly the amount of time it takes light to go to Saturn and back to Earth, we saw Saturn get brighter in x-rays. Now one can imagine in the future using Jupiter or Saturn to let us know if the far side of the sun flares. This could be important to astronauts traveling deep in the solar system.

Narrator: Astronomers were also able to take advantage of a rare alignment of Saturn's moon, Titan. On January 5, 2003, Titan crossed in front of the Crab Nebula, which is a very strong X-ray source.

Scientist: Now because the Crab pulsar and the nebula is so bright in x-rays, we effectively got a good old-fashioned x-ray of Titan, just like you get when you go to the doctors office and they put a strong x-ray beam on one side and a film on the other side and your arm, your finger, or whatever you might have broken, in between. These data reveal elements high up in the atmosphere of one of the few bodies in the solar system that actually has liquid on its surface.

Narrator: Let's return to Jupiter. Scott Wolk describes some of what Chandra has revealed about this gas giant planet.

Scientist: Jupiter can also reflect x-rays, just like Saturn, but it has a strong magnetic field which makes things a lot more interesting. Charged particles, possibly from the Sun in what's called the solar wind, possibly from material sputtered off the moon Io, can get captured by the magnetic field of Jupiter and driven towards the million-volt environment above the planet's poles. I say possibly because the region where the x-rays are seen on Jupiter is actually a little bit too close to the poles to be coming from either source directly and there's some new astrophysics we need to learn. Just in time comes the flyby of the New Horizons spacecraft past Jupiter in 2007 on its way to Pluto. It will be mapping the magnetic field of Jupiter while Chandra is watching for any odd behavior.

Narrator: While we've sent spacecraft out to study the outer Solar System, certain secrets may only be revealed through the X-rays that Chandra can detect. Scientists will continue to use the observatory to unlock the mysteries of our planetary neighbors.