Comets are raining down water on a faraway planet

The Eta Corvi solar system is like a window into how our own solar system looked billions of years ago. All of Eta Corvi is being bombarded by giant comets — the exact same process that created Earth's oceans.

What's more, observations by NASA's Spitzer telescope show signs of huge dust clouds close to the system's star. The most obvious way to create dust clouds like that is if a huge comet collided with a planet near the star. Analysis of the light coming from the dust suggests it's composed of water ice, organic compounds, and rock, all of which points very strongly to a big comet.

We can't be sure, but it's certainly possible that this comet actually hit a planet located in Eta Corvi's habitable zone. If that's the case, then we're witnessing what is essentially a reenactment of the formation of our planet's oceans. Earth got huge amounts of its water and carbon-based organic compounds during an epoch known as the Late Heavy Bombardment, in which comets from the Kuiper Belt beyond Neptune began hurtling towards the inner solar system due to gravitational disturbances from Jupiter and Saturn.

We probably owe the existence of life as we know it to a bunch of comets, and now the Eta Corvi system is in the middle of the exact same process. The Eta Corvi system even has its very own answer for the Kuiper Belt, as astronomers had previously discovered the existence of a massive ring of cold dust located about 150 astronomical units from the star, meaning the distance is 150 times that between the Sun and Earth.

Lead researcher Carey Lisse explains the potential of studying what's going on in the Eta Corvi system:

"We believe we have direct evidence for an ongoing Late Heavy Bombardment in the nearby star system Eta Corvi, occurring about the same time as in our solar system. We think the Eta Corvi system should be studied in detail to learn more about the rain of impacting comets and other objects that may have started life on our own planet."

Because a lot of what's going on in the Eta Corvi system is too dim for our telescopes to see, we can't be sure of everything that's going on there. But it does appear that we're witnessing something very close to what happened in our own solar system more than 3.8 billion years ago, which is an exciting thought. Indeed, as we get better and better at observing alien solar systems, each in different phases of development, we may be essentially able to reconstruct our solar system's entire past and future. Eta Corvi is just one pretty crucial piece of that cosmic reenactment.

Via the Jet Propulsion Laboratory. Image by NASA/JPL-Caltech.