Expert: Courtney Seligman - 12/4/2008

Question
Hi,

What would happen to the planets in our solar system if the sun just vanished in the blink of an eye?

Answer
For one thing, they would get very cold as their surface heat was radiated into space, and not replaced. This wouldn't be as important for the Jovian planets, as some of their heat comes from their insides, but the Terrestrial planets' temperatures would drop by tens of degrees per hour (Venus would cool more slowly, because of its thick atmosphere), and within a few days or weeks, depending upon the planet, they would all be two to three hundred degrees below zero Fahrenheit, and within a few years, most would be within a few degrees of absolute zero.

For another, they would move away from each other into interstellar space, as each followed a straight-line path in whatever direction and with whatever speed it was moving at the moment the Sun disappeared. They would continue to move around the Galaxy, with about the same motion the Sun had before it disappeared, but would gradually spread out, to distances comparable to those between the stars, over a few hundreds of thousands of years.

Courtney Seligman