"Without Mars, Earth's orbit would be missing major climate cycles. What would humans and other animals even look like if Mars weren't there?"
The findings potentially solve the paradox of how liquid water seems to have persisted on Mars even when the climate grew too cold.
Exploration advocates are pushing back against the planned cancellation of NASA's Mars sample return project, saying it could potentially find evidence of Red Planet life.
"The Chinese may well beat the U.S. with a grab sample."
Outside Earth's protection, space travellers will be routinely exposed.
The HiRISE camera on NASA's Mars Reconnaissance Orbiter just notched a big milestone, snapping its 100,000th photo of the Red Planet.
"We did the simplest thing that could be done — we just mapped them and pieced them together."
For the first time, we can see and hear lightning-like discharges in Mars' thin atmosphere.
Humanity's exploration of Mars should be organized around the search for signs of past or present Red Planet life, according to a new report from the U.S. National Academies.
A new view of Mars showcases a dramatic impact crater on the Red Planet with its debris wings unfurling across the surface like a butterfly in flight.