To be a planet, NASA says an object must be big enough that its gravity has cleared away any other objects of a similar size near its orbit around the Sun. I can understand how something can clear ...

Discover the hottest planet in the solar system, why Venus is hotter than Mercury, planet temperature facts, greenhouse effect and important solar system details. The planets in the solar system have ...

Scientists have discovered a bizarre planetary system where a rocky world orbits farther out than giant gas planets, defying ...

Editor's note: This article was updated March 25 at 11:40 a.m. ET to account for the recent discovery of new moons around Saturn and Jupiter. The total number of planetary moons and small-body ...

Using a new technique that partly relies on artificial intelligence, researchers spotted potentially more than 10,000 new ...

Looking for a sky event this week? Check out our full Sky This Week column. May 24: Egeria slides on by After reaching superior conjunction midmonth, Mercury is increasing in visibility and should be ...

Unlike previous season finales, For All Mankind's Season 5 finale ends on a mysterious and ominous cliffhanger. Here's what ...

Neptune has only been visited by one spacecraft, NASA’s Voyager 2 in 1989. Nereid was discovered 40 years earlier by Dutch ...

Despite being the closest planet to the sun, Mercury has thick deposits of ice at its poles, and now we may understand the events that formed them over just one Mercurian day ...

Somewhere around 50 light-years from Earth, a dim red dwarf star called LHS 1903 hosts four planets arranged in an order that ...

Two decades ago, the International Astronomical Union—which defines and names celestial bodies—redefined the criteria for being a planet, putting Pluto into the new category of dwarf planet ...

NASA’s Psyche spacecraft successfully completed a flyby of the Red Planet on May 15, coming within 2,864 miles (4,609 ...