Look at what each planet needs to complete a cycling of the sun.

Well, here's a close-up image of the Andromeda Galaxy - each dot is a star This image was taken by the Hubble Space Telescope, the largest and sharpest image ever taken from the Andromeda Galaxy. The full image contains 1.5...

Cesium 137 is produced in nuclear explosions and nuclear reactors. This is a big problem with low half-life isotopes. But it has many practical uses. It is used in radiation therapy. It is dangerous that most compounds of cesium are...