Life may once have been possible on Venus, based on how it spins

Venus' carbon dioxide-rich atmosphere and high temperatures make it one of the most inhospitable places you could imagine.

However, scientists conducted research to find that Venus may once have been not too dissimilar to Earth, with a much cooler surface and even oceans.

A change to the way Venus spins may have changed a once habitable environment into the scorching, oxygen-depleted environment the planet is now home to.

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With a relatively constant average temperature of 864 degrees Fahrenheit day and night, Venus is the hottest planet in our solar system, according to Space.com.

To make an already hostile environment even more inhospitable, the planet's atmosphere predominantly consists primarily of carbon dioxide, according to research published in The Astrophysical Journal Letters. However, it wasn't always the case that Venus was home to such extreme conditions.

Working with NASA and the University of Washington, researchers at Bangor University found that Venus may once have been home to a much cooler surface and even oceans. They found that Venus may once have been a planet not too dissimilar to Earth after all, and it may all be down to how the planet spins.

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Venus now rotates in the opposite direction to Earth, but it's thought that Venus once rotated in the same direction as our planet. One theory suggests a substantial asteroid impact may have caused the direction of the planet's rotation to change, according to Ask an Astronomer.

The planet also spins at a relatively slow speed, taking 243 days to rotate around itself fully, according to Scientific American. It's the planet's slow rotation that has prevented the formation of new liquid oceans on its surface.

Contrary to what one might expect, it may have been oceans originally present on Venus that led the planet to end up spinning so slowly in the first place, according to oceanographer at Bangor University, Mattias Green, and his colleagues at NASA and the University of Washington.

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The friction between an ocean and its seabed at low tide and high tide acts as a sort of brake on the rotation of a planet — this is also the case for Earth, but only to a very limited extent, leading to an average day being extended by roughly 20 seconds every million years.

The researchers suggested the tidal “braking” would have hampered the planet's rotation speed, eventually leading to conditions that would have made the presence of oceans on the planet unsustainable.

To confirm these ideas, Green and his colleagues carried out a series of simulations on a numerical tidal model. The team investigated how the tides of potential oceans with different depths could have influenced the rotational speed of Venus.

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It seems that, within the space of around ten to 50 million years, this “tidal brake” could possibly have slowed Venus down from an Earth-like rotational speed to its current rotational speed.

“This work shows how important tides can be to remodel the rotation of a planet, even if that ocean only exists for a few 100 million years, and how key the tides are for making a planet habitable,” said Green.

According to the research, it's quite plausible that Venus was once covered by oceans and that life there may even have been possible at one point.

The deceleration of the planet's rotational speed then led to the hostile environmental conditions we find on Venus today.