The bottom line is that finding orphan planets - small, faint, and located who-knows-where - is not for the faint of heart. The task is comparable to observing a match flame at the distance of Pluto. The WISE satellite, a hi-tech, space-based infrared telescope especially suited for such work, has found only a few.

On Mars, where the air is spare - a hundred times less dense than on Earth - someone could hear you scream. But you'd have to really strain to get anyone's attention. On the Red Planet, where the wind is high-pitched and faint, even a symphony orchestra will sound as thin as cheap gruel.

Jupiter, a world far larger than Earth, is so warm that it currently radiates more internal heat than it receives from the Sun.

Seth Shostak Quotes