The universe is a strange, amazing place.

Largest known exoplanet puzzles astronomers

A newly discovered alien planet has a record-breaking low density – about the same as that of balsawood. Astronomers say the planet, called TrES-4, could be losing grip of its puffed-up atmosphere.

"TrES-4 is the largest known exoplanet," says Georgi Mandushev from Lowell Observatory in Arizona, US. "Because of the planet's relatively weak pull on its upper atmosphere, some of the atmosphere probably escapes in a comet-like tail."

Mandushev's team discovered TrES-4 in a project called the Trans-Atlantic Exoplanet Survey (TrES), which uses a network of small automated telescopes in the Canary Islands and in Arizona and California in the US. They look for the slight dimming of stars when planets pass in front of them, blocking out some starlight.

The periodic dimming of a star 1400 light years away in the constellation Hercules revealed the presence of TrES-4, which orbits the star every 3.5 days. Follow-up observations using large telescopes in Hawaii and Arizona showed that the planet is just 0.84 times as massive as Jupiter.

But the amount of dimming makes sense only if the planet is about 1.7 times as wide as Jupiter. Astronomers calculate that its average density is only about 0.2 grams per cubic centimetre – less dense than a wine cork. "It's way lower than the density of water," says Mandushev.

This is where science gets fun. TrES-4 breaks the paradigm. We need new theories to explain it, new models of how planets work, and this is how we increase our understanding.

Just when we think we're starting to get a handle on things - bam!

Just hit the ball, and touch 'em all....

756!!!!!