For the better part of a century, we believed there were nine planets in our solar system ... Pluto Has the Biggest Heart in the Solar System It was only after images from 2015 arrived that ...

Saturn, the sixth planet from the Sun, captivates scientists with its massive size, stunning rings, and diverse moons.

Mike Brown is convinced that beyond Neptune, at the far reaches of our solar system, there's an unseen giant planet. "This is the 5th largest planet in our solar system, lurking out there ...

Astronomers have found a planet that orbits at an angle of 90 degrees around a rare pair of peculiar stars. This is the first time we have strong evidence for one of these 'polar planets' orbiting a ...

but also provide vital information for future uncrewed missions to the third largest planet in the solar system. [Related: Uranus’s quirks and hidden features have astronomers jazzed about a ...

With a radius of 2,106 miles, Mars is the seventh largest planet in our solar system and about half the diameter of Earth. Its surface gravity is 37.5 percent of Earth’s. Mars rotates on its ...

Mars, the fourth planet from the sun, is a dry, rocky world. Its famous red color has earned it the nickname the Red Planet. Mars has fascinated people throughout history, and today, it is one of ...