Does Venus host alien life? That's the big question after a recent study spotted phosphine -- a gas with possible biological origins -- in the planet's clouds. We won't have answers until further investigation, but clues to the planet's history of habitability could be closer than expected.
Yale University astronomers Samuel Cabot and Gregory Laughlin said we should look to the moon for a peek into Venus' past. They explained why in a paper accepted into the Planetary Science Journal this month.
The study suggests "asteroids and comets slamming into Venus may have dislodged as many as 10 billion rocks and sent them into an orbit that intersected with Earth and Earth's moon," Yale said in a statement. These impacts were more common billions of years ago, meaning bits of ancient Venus could remain as well-preserved meteorites on the lunar surface.
Venus is currently an inhospitable place with a toxic atmosphere. It's the hottest planet in our solar system and is experiencing what NASA calls "a runaway greenhouse effect." But it wasn't always like this. Venus may have had oceans and even been habitable for life as recently as 700 million years ago.
We may not have to wait too terribly long to bring new moon rocks back to Earth for the first time since the 1970s. NASA is encouraging private companies to launch sample collection missions and has its own ambitious plans to return humans to the moon in 2024.
Chemical analysis of moon rocks could tell us if they're original parts of the moon or meteorites from elsewhere.
"An ancient fragment of Venus would contain a wealth of information," Laughlin said. "Venus' history is closely tied to important topics in planetary science, including the past influx of asteroids and comets, atmospheric histories of the inner planets, and the abundance of liquid water."