A planet illuminated against the blackness of space, its axis tilted to the left of the frame. The planet has a wide band of pale orange around its equator, pale blue regions above and below that, and wispy white clouds scattered around its face.

Discovery Alert: An Ice-Cold Earth?

A candidate planet that might be remarkably similar to Earth, HD 137010 b, has one potentially big difference: It could be colder than perpetually frozen Mars.

NASA Science