Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, ...

Upon further investigation, it seems that Gliese 581d may be the only one of the two actually in the habitable zone, and its ...

Astronomers have discovered that "super-Earth" planets may exist on wider orbits than previously thought — and this implies these rocky, or "terrestrial," worlds are far more common than was suspected ...

Another brown dwarf is present in this system, but is too far away - about 250 times the distance between Earth and the sun - for its gravitational pull to measurably disturb the other two. Of the ...

The reality is, Venus will be larger and brighter. Saturn will be smaller and dimmer. These two planets would depict the "eyes" of the smiley face. The "smile" would be made by the crescent moon.

Even though Saturn is physically far larger than Mercury, at over 20 times wider, its distance of 1.5 billion kilometers from Earth is so much farther away that the two planets appear to be nearly ...