A planet-size object that possibly once visited the solar system may have permanently changed our cosmic neighborhood by ...

Astronomers Find 4 New Planets. ... system," more like our own — one that has an Earth-sized planet in the inner region and a Jupiter-sized planet in the outer region, said Alan Boss, a planet ...

Artist's impression of Planet Nine – a suspected “wide-orbit” planet – with the Sun in the distance; Neptune's orbit is shown ...

Astronomers have discovered six planets orbiting a bright star in perfect resonance. The star system, 100 light-years from Earth, was described on Wednesday in a paper published in the journal ...

Using computer models of the four outer planets, the team carried out 50,000 simulations of such flybys, each over 20 million years, while altering certain parameters of each visitor, ...

Using computer models of the four outer planets, the team carried out 50,000 simulations of such flybys, each over 20 million years, while altering certain parameters of each visitor, including ...