The curious minds at What If imagine a second Earth hiding in our solar system, exploring how it could exist and its effects on our planet and orbit.

In a groundbreaking study,Harvard physicist Dr. Avi Loeb has brought new attention to an unusual interstellar object, 3I/ATLAS, discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) ...

The workings of our solar system are roughly the same now as they have been for millions of years. Moons circle their planets, the planets circle the sun, the sun’s magnetic fields and sunspots wax ...

Far from the Sun’s heat, orbiting the outer planets of the solar system, are moons with oceans of liquid water beneath their frozen surfaces. Keith Cooper finds out how planetary scientists are ...

A NASA mission to study the heliosphere—the sun's magnetic bubble that shields our solar system—and develop a better understanding of space weather was launched from the agency's Kennedy Space Center ...

Add Yahoo as a preferred source to see more of our stories on Google. Our solar system is mostly arranged along one plane in space, as in this not-to-scale artist's diagram. NASA/JPL, CC BY If you’ve ...

The U.S. planetary science community is sounding the alarm about plans to discard a nuclear technology that has powered dozens of NASA missions over the past 50 years But RPS is expensive, costing ...