Largest Planet Ever Discovered

Huge, lightweight discovery puzzles scientists
A 3D rendered simulation of TrES-4, with its host star, which is bigger and hotter than the Sun, and about ten times larger than the planet, itself. Astronomers also speculate that the large size and...   (Jeffrey Hall, Lowell Observatory)
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(Newser) – Forget Jupiter. Scientists have discovered the largest planet out there—a "puffy" space mass almost twice the size of our solar system's gas giant. But the find is posing more questions than answers, reports: TrES-4’s mass is large but its density is about the same as balsa wood, which has confounded astronomers' theoretical models.

The exoplanet is "way bigger than it's supposed to be," one of its puzzled discoverers said. "For its mass, it should be much smaller."  TrES-4 is 1,400 light years from Earth and was discovered by scientists using a telescope that tracked its orbit around its parent star—a giant that will swallow the poor planet up in about a billion years.