The relative quantities of volatile gases like methane and ethane can reveal key details about distant Kuiper Belt objects.

Astronomers have discovered an Earth-size planet orbiting an ultracool red dwarf star similar in size to Jupiter. The red dwarf, located some 55 light-years away, is 100 times less bright than the ...

A dwarf planet is defined as a world massive enough to be round but still in a part of space where other objects of similar size can cross its orbit, according to NASA. "Major" planets ...

Here's How to See It When a medium-mass star roughly the same size as the Sun ... s impression shows a planet (left) that has ...

A decades-old cosmic mystery may finally be solved. Scientists now suspect that the strange X-ray glow from a distant white ...

Why was Pluto reclassified as a dwarf planet? One might think that it’s purely a matter of size. Mercury, the smallest of the ...

Some are the size of small stones and pebbles. Some measure hundreds of kilometres across. The largest object is the asteroid belt is the dwarf planet Ceres, which is 950km in diameter (that's ...

Such stars are about the same size as a Jupiter-like planet but are more massive, making them much less likely to have been torn apart by the white dwarf. WD 2226-210 has some similarities in X ...

A surprising chemical difference between Pluto and Sedna, another dwarf planet in the distant Kuiper ... "Since Gonggong is similar in size to Sedna, we believe methane must have escaped from ...