The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

The formation of our solar system from a singular nebula raises an intriguing question: why did each planet develop with a ...

Stargazers will be treated to a rare seven-planet alignment in February. This is what scientists hope to learn.

Mercury joins the night sky to complete a 7-planet alignment just after sunset for the end of February. Saturn leaves our ...

While the composition of gas and dust in a molecular cloud is fairly uniform, everything changes once a star begins to form.

An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit ...

Look to the bright moon for a convenient guidepost; it’ll pose with a different planet from one day to the next. Stand out dates include January 31 when the moon is closest to Saturn ...

Staring up at the night sky, you might see thousands of stars sprinkled above the horizon. It feels as though you can see so ...

Currently, six planets are visible in the sky in a line—and soon enough, a seventh will join them, according to the BBC. And ...

Kepler was one of the most successful exoplanet-hunting missions so far. It discovered 2,600 confirmed exoplanets—almost half ...