A collision between planets,like the one illustrated, could have caused the odd orbit of XO-3b (Illustration: NASA/JPL-Caltech)
BILLIONS of years ago, something kicked planet XO-3b into a cock-eyed orbit. The culprit may have been another planet, which would mean planets can bounce each other around like cosmic billiard balls.
Guillame Hébrard of the Institute of Astrophysics in Paris and colleagues detected an unusual colour shift as XO-3b passed in front of its star. The pattern suggests that its 3.2-day orbit is tilted by 70 degrees (see diagram). “If confirmed, this might be the first planet of this type,” says…
