James Webb telescope could detect life on Earth from across the galaxy, new study suggests

James Webb Space Telescope in outer space.
A new study suggests that the James Webb Space Telescope could detect Earth's human civilization from across the galaxy (Image credit: Getty Images)

The James Webb Space Telescope (JWST) would be able to spot the signs of our civilization on Earth if it was spying on us from another star system in the Milky Way, a new study shows. The finding raises hopes that the state-of-the-art spacecraft could detect alien civilizations as it stares out toward distant worlds in our galaxy.

Since launching in late 2021, JWST has been predominantly peering out into the deepest reaches of the cosmos in search of clues about how the early universe formed. But one of the telescope's secondary objectives is to analyze the atmospheres of nearby exoplanets, or planets beyond the solar system, to look for gases produced by biological life, known as biosignatures, and chemicals produced by advanced alien civilizations, known as technosignatures.

Related: Are aliens real?

But despite being the most advanced telescope currently in operation, it is still unclear how well JWST will be able to spot the tell-tale signs of intelligent life. To answer this question, researchers decided to test whether the space telescope could successfully detect intelligent life from the only planet in the universe that is known to be both habitable and currently inhabited — Earth.

In the new study, uploaded to the pre-print server arXiv on Aug. 28, researchers took a spectrum of Earth's atmosphere and deliberately decreased the quality of the data to mimic how it would look to an observer dozens of light-years away. The team then used a computer model, which replicated JWST's sensor capabilities, to see if the spacecraft could detect the key biosignatures and technosignatures from the dataset, such as methane and oxygen, produced by biological life, and nitrogen dioxide and chlorofluorocarbons (CFCs), which are produced by humans.

The results, which have not yet been peer-reviewed, show that JWST could likely detect all the key markers of non-intelligent and intelligent life in our planet's atmosphere.

Related: There may be hundreds of millions of habitable planets in the Milky Way, new study suggests

A graph showing the spectrum of Earth's atmosphere

This graph shows the raw atmospheric data used in the new study. Specific biosignatures and technosignatures are highlighted in different colors. (Image credit: Lustig-Yaeger, et al)

The researchers noted that the quality of the altered dataset is roughly equivalent to JWST observations of planets from TRAPPIST-1 — a star system containing seven exoplanets that orbit a red dwarf star around 40 light-years from Earth. This suggests the telescope should be able to detect life or alien civilizations on exoplanets within 40 light-years of Earth. But the team believes JWST could possibly detect signs of extraterrestrial life up to 50 light-years from Earth.

Only around 20 exoplanets have been officially discovered within a 50-light-year radius of Earth, but based on the number of suspected stars in this region of space, experts predict that there may actually be as many as 4,000 exoplanets within JWST's reach, according to Project EDEN, an international astronomical collaboration dedicated to finding potentially habitable planets close to Earth.

However, this doesn't guarantee that JWST would be able to detect life on other planets.

7 planets surrounding a star

An artist's interpretation of what the TRAPPIST-1 system might look like. (Image credit: Getty Images)

Detecting biosignatures and technosignatures on other worlds "may prove challenging to interpret without contextual knowledge about the habitable environment," the researchers wrote. In this study, the team already knew which markers to look for, but on an exoplanet with different conditions and alternate potential life forms or technologies those life-signatures may not be as obvious, they added.

JWST has already made some interesting discoveries about exoplanets near Earth. The telescope spotted water on the Neptune-size exoplanet GJ 1214b, which is around 40 light-years from Earth, and found that TRAPPIST-1b, the second-closest exoplanet to the star in the TRAPPIST-1 system, likely has no atmosphere at all due to its extreme heat. The spacecraft also glimpsed a gigantic dust storm in the atmosphere of VHS 1256 b, a "super-Jupiter" exoplanet 40 light-years from Earth.

Closer to home, JWST has also detected giant geysers gushing out of Saturn's moon Enceladus, which could contain the chemical ingredients needed for life. And further out into the cosmos, the spacecraft has also glimpsed potentially life-giving carbon compounds in an infant star system more than 1,000 light-years from Earth.

Harry Baker
Staff Writer

Harry is a U.K.-based staff writer at Live Science. He studied Marine Biology at the University of Exeter (Penryn campus) and after graduating started his own blog site "Marine Madness," which he continues to run with other ocean enthusiasts. He is also interested in evolution, climate change, robots, space exploration, environmental conservation and anything that's been fossilized. When not at work he can be found watching sci-fi films, playing old Pokemon games or running (probably slower than he'd like). 

  • Thomas Thompson
    Unless NASA or some other government entity has faster-than-light-speed travel all figured out, it would occur to me that loading all the rich and powerful elite humans on giant spaceships and sending them off to a new home somewhere else in the Galaxy is a pipe dream. And that's the idea, isn't it? There are 8 billion of us stewing in our own juices on this little, soon-to-be-depleted rock, and 99.99999% of us are going NOWHERE! How about spending all that money on a solution to global warming, instead?
    Reply
  • Jay R. Clemons
    Thomas Thompson said:
    Unless NASA or some other government entity has faster-than-light-speed travel all figured out, it would occur to me that loading all the rich and powerful elite humans on giant spaceships and sending them off to a new home somewhere else in the Galaxy is a pipe dream. And that's the idea, isn't it? There are 8 billion of us stewing in our own juices on this little, soon-to-be-depleted rock, and 99.99999% of us are going NOWHERE! How about spending all that money on a solution to global warming, instead?
    "And that's the idea, isn't it?" Well, no, that isn't the idea of the JWST. By all means, we NEED to drastically reduce our carbon footprint, planet-wide. But we should also be using our best technology to find out as much as possible about the universe around us. Meanwhile, how about spending some money convincing 3/4 of Republicans that global warming is an existential threat?
    Reply
  • Steamdude
    Given to hyperbole at all? How 40 to 50 light years away translates to "across the galaxy" literally boggles my mind, given the latter would suggest a distance of somewhere around 50,000 LY! It betrays a certain ignorance of the distances involved, or a tendency towards click bait, or both.
    Reply
  • Shrike
    Steamdude said:
    Given to hyperbole at all? How 40 to 50 light years away translates to "across the galaxy" literally boggles my mind, given the latter would suggest a distance of somewhere around 50,000 LY! It betrays a certain ignorance of the distances involved, or a tendency towards click bait, or both.
    That was the first thing I thought. 45 LY is hardly "across the galaxy."
    Reply
  • Shrike
    Thomas Thompson said:
    Unless NASA or some other government entity has faster-than-light-speed travel all figured out, it would occur to me that loading all the rich and powerful elite humans on giant spaceships and sending them off to a new home somewhere else in the Galaxy is a pipe dream. And that's the idea, isn't it? There are 8 billion of us stewing in our own juices on this little, soon-to-be-depleted rock, and 99.99999% of us are going NOWHERE! How about spending all that money on a solution to global warming, instead?
    We learned much about the greenhouse effect by observing Venus. The JWST was money well spent. It may result in a paradigm shift in our understanding of the cosmos and the big bang. Space exploration is a good thing. It's not an either / or scenario. How about allocating much of the military budget for greener energy instead.
    Reply
  • Roj5
    Thomas Thompson said:
    How about spending all that money on a solution to global warming, instead?
    Try convincing a few of the posters on here there is an issue with Global Warming and then take that to the masses opposed to it.
    Reply
  • Shrike
    Roj5 said:
    Try convincing a few of the posters on here there is an issue with Global Warming and then take that to the masses opposed to it.
    Who on here has given any indication that global warming isn't an issue?
    Reply
  • Roj5
    Shrike said:
    Who on here has given any indication that global warming isn't an issue?


    One example thread here with September posts https://forums.livescience.com/threads/this-was-the-hottest-summer-ever-recorded-on-earth.18158/#post-38265
    There are others which is a shame as this is, for me, a site where science is discussed and not refuted.
    Reply
  • Shrike
    Roj5 said:
    One example thread here with September posts https://forums.livescience.com/threads/this-was-the-hottest-summer-ever-recorded-on-earth.18158/#post-38265
    There are others which is a shame as this is, for me, a site where science is discussed and not refuted.
    Thought you were referring to this article and the this topic. The discussion is about whether or not funding space exploration is good. Roj5 thinks it isn't because of global warming.
    Reply