A Mars-size object called Theia smashed into Earth, and the debris coalesced into the moon. Now scientists believe they may have identified pieces of Theia at the bottom of Earth’s mantle. A new study ...

For close to a century, scientists have been trying to marry Albert Einstein’s General Theory of Relativity and quantum theory—our two best bets on understanding the universe on a macroscopic and ...

3I/ATLAS, comet or alien spaceship? Turns out, we are not ready to give this interstellar object the clean chit. A scientist says it is strange that it will pass exactly near Jupiter's Hill radius. At ...

Science fiction loves to take us to desolate alien worlds with low-gravity, and envision creatures evolved to those or humans adapted to those conditions or zero-gravity in space, and many planets we ...