You’ve got heard of scorching Jupiters. You’ve got heard of mini-Neptunes. You’ve got heard of super-Earths. However have you ever heard of Eyeball Planets? Yep – planetary scientists suppose there is perhaps a sort of exoplanet on the market that appears disturbingly like a large eyeball. Simply sitting there. Staring.
But it surely’s really not as bizarre because it sounds – the looks of those our bodies has to do with tidal locking.
Tidal locking is when an orbiting physique rotates on the similar fee that it orbits. Meaning it at all times has one facet going through the physique it’s orbiting, and the opposite facet at all times going through away. The Moon, as an example, is tidally locked to Earth, that is why we by no means see its far facet from right here.
Earth is not tidally locked to the Solar – that is why we’ve a day/night time cycle – however we all know there are exoplanets which can be tidally locked to their stars. Which suggests one facet is in perpetual day, and the opposite in perpetual night time.
Every bathed in such completely different circumstances, the day facet would possibly look very completely different from the night time facet. Relying how shut the planet is to the star, one facet might be dry, all of the water burned away by stellar radiation; however the different facet, in darkness, might be one big ice cap wrapping round, terminating in a glacial ring. One thing like this:
In response to a 2013 examine within the journal Astrobiology, that ring might be liveable – in perpetual twilight, with water from the melting glaciers enabling a fertile area the place vegetation may develop.
That is a scorching eyeball. Then, in response to astronomer Sean Raymond, there’s the icy eyeball, farther from its star’s warmth. It nonetheless has a night-side ice cap. However the star facet is not dry, barren Earth; as a substitute it is a liquid ocean, which once more might be liveable, like Earth’s teeming seas.
“Scorching eyeball and icy eyeball planets are excessive instances, however any planet that’s tidally locked to its star is more likely to look very completely different on its day facet and its night time facet,” Raymond famous.
“Variations may come from clouds clustered in sure areas, from preferential melting of ice on the day facet or freezing of ice on the night time facet, or from any variety of different attainable sources. The galaxy could also be plagued by wild forms of eyeball planets!”
Properly, it is a massive place on the market, and big area eyeballs definitely aren’t the strangest thought ever. Who is aware of what might be attainable?