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

New research suggests that dark energy isn't needed to explain the acceleration in the expansion of the universe — instead suggesting giant voids in space are creating an illusion.

NASA's flagship space telescope captured flares from the disk of superheated material around the black hole, revealing the dynamic—and explosive—physics at our galaxy's core.

These alignments aren't the neat planetary queues you see in diagrams and illustrations of the Solar System. That's not a thing that actually happens in the real Universe, sadly. Yet the planets ...

The moons around planets in the Solar System are natural satellites ... circular orbit it must be travelling at the right speed. The diagram shows a satellite orbiting the Earth.

Space photos remind us that, around every corner of our vast universe, something spectacular ... humanity's first landing on a moon in the outer solar system when it touched down on Titan.