Spraying particles into Earth's atmosphere to try and cool a warming planet might sound like a good idea in theory, but it will only work if it's done properly – and even then, it could carry risks that might spill beyond our control, scientists caution.

Mercury will reach its greatest eastern elongation on Oct. 29, marking one of the best evenings to see the planet this fall as it appears farthest from the sun's glare in the twilight sky. As the solar system's innermost planet,

There are a couple of ways that scientists can date planets, so which planets formed first in our solar system?

Mercury reaches its greatest eastern elongation on October 29, appearing farthest from the Sun in the southwestern sky, offering a brief window for observation after sunset.

Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the discovery of Pluto in the 1930s. Labeled as planet X, prominent astronomers had put it forward as an explanation for Uranus’s orbit ...

"It was just a matter of time before we found them."

Research shows Jupiter’s strong gravitational pull may have protected Earth by keeping its orbit steady and preventing it from drifting toward the Sun.