The mysterious Oort cloud is the source of many of our solar system's comets, but astronomers still have no idea what it ...

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

Did you know our solar system might have had an extra planet? Scientists believe a mysterious ninth planet once existed but ...

In February 2025, all seven of our planetary neighbors will be visible from Earth. So what does such a planetary alignment ...

Astronomers for the first time have deciphered the three-dimensional structure of the atmosphere of a planet beyond our solar ...

That path is called the ecliptic, and it exists because all planets in our solar system orbit around the sun on roughly the same plane. You may like Watch 'planetary parade' online for free on Jan ...

That path is called the ecliptic, and it exists because all planets in our solar system orbit around the sun on roughly the same plane. Astronomers, on the other hand, look for more specific ...

NASA said the system is thought to be moving at least 1.2 million miler per hour, nearly twice as fast as our solar system.

Sure, they’re particles and rocks, but they’re still a fascinatingly long way from home. Alpha Centauri is the star system ...

Why is Pluto no longer a planet? Discover the real reason behind Pluto’s reclassification as a dwarf planet and the science that led to this change.

But turning our nine-planet solar system into eight just earned Pluto more fans. This year also marks the 10th anniversary of Pluto's first dedicated flyby mission. NASA’s New Horizons spacecraft ...