The James Webb Space Telescope has captured its first direct images of carbon dioxide in a planet outside the solar system in HR 8799, a multiplanet system 130 light-years away that has long been a ...

So exactly how many solar system moons have we found? The answer, it turns out, depends on your definition of a moon. The International Astronomical Union (IAU) officially recognizes 288 planetary ...

"These objects really could be anywhere in the solar system at any given time." One million alien visitors from another star system could already be lurking in the solar system. We aren't talking ...

If the team’s version of planetary definition is indeed widely adopted — and to be clear, that’s a long shot at best — it would greatly expand the number of planets in our solar system ...

The stars as seen from Earth would have looked dimmer 14 million years ago, as the solar system was in the middle of passing ...

So exactly how many solar system moons have we found? The answer, it turns out, depends on your definition of a moon. But this is likely just "the tip of the iceberg," Edward Ashton, an astronomer ...