"It's been such a puzzle that there was liquid water on Mars, because Mars is further from the sun, and also, the sun was ...

How far away is Mars? To determine how long it ... "It takes the Earth one year to orbit the sun and it takes Mars about 1.9 years (say 2 years for easy calculation) to orbit the sun.

Orbital dynamics show that President Trump’s pledge to land astronauts on Mars couldn’t happen until 2029 at the earliest.

There’s another complicating factor: Mars has a far thinner atmosphere ... barrier makes it easier for the sun’s high-energy particles to strip away the red planet’s atmosphere, which ...