Are We Close To Finding An Earth-Like Atmosphere On Another Planet? Astronomers Think So

Astronomers may be on the verge of confirming something that, until recently, seemed like science fiction: the existence of an Earth-like atmosphere around a planet outside our solar system. Preliminary observations from the James Webb Space Telescope (JWST) suggest that TRAPPIST-1e, a rocky planet orbiting a small red dwarf star 40 light-years away, could be a candidate.

Why TRAPPIST-1 Matters?

Discovered in 2016 by Belgian astronomers, the TRAPPIST-1 system is unusual. The star is barely the size of Jupiter, yet it hosts at least seven rocky planets, three of which sit in the “habitable zone”- the orbital sweet spot where conditions might allow liquid water.

TRAPPIST-1e, roughly Earth-sized, is the system’s most promising candidate for habitability.

Unlike its innermost neighbor, TRAPPIST-1b, which JWST confirmed has no atmosphere, TRAPPIST-1e remains an open question.

What Webb Telescope Found?

A study published in The Astrophysical Journal Letters reports that four Webb observations in 2023 could not rule out an atmosphere on TRAPPIST-1e. While this doesn’t prove one exists, it leaves the possibility alive- an exciting prospect for astronomers.

The data suggest the planet likely lost its original hydrogen-rich atmosphere due to strong radiation from its star, similar to what happened to Earth early in its history. Now, scientists are testing whether it may have developed a secondary atmosphere, potentially rich in nitrogen, like Earth or Titan, Saturn’s icy moon.

How Scientists Detect Atmospheres?

Astronomers study atmospheres by watching planets transit or pass in front of their stars. During these moments, some starlight filters through the planet’s atmosphere, if one exists. Different gases absorb light at specific wavelengths, allowing scientists to identify their chemical makeup. So far, Webb has excluded Venus-like (carbon dioxide–heavy) atmospheres for TRAPPIST-1e, narrowing the possibilities to something more Earth-like. A new round of 15 Webb observations, already two-thirds complete, could provide a definitive answer.

What’s At Stake?

Confirmation of an atmosphere would be groundbreaking. Red dwarfs like TRAPPIST-1 are the most common stars in the universe. If one of their planets can retain an atmosphere, it would dramatically expand the odds of habitable worlds elsewhere. But even a null result would be significant as it would highlight how rare Earth might be.

Scientists caution that the results are “immensely exciting, but incomplete.” Computer simulations suggest TRAPPIST-1e could be a desert-like rock or a water-rich ocean planet- both scenarios remain possible.