Our quest for habitable planets that could support life has just reached a whole new level – one that extraplanetary beings might admire if we one day communicate with them.
Following a successful launch in late 2021, NASA’s James Webb Space Telescope is now almost a million miles from Earth and has completed an extensive commissioning process that has included the commissioning of 17 scientific instrument modes and countless tests. The mighty machine marvel, now fully operational, launches the first of many observations over a possible 20-year run in space. The telescope’s instruments aim to capture faint objects that could be more than 13.5 billion years away, including galaxies that formed just a few hundred million years after the Big Bang.
As Webb searches for clues to how the Universe formed, it will also attempt to capture signatures of habitability in the atmospheres of exoplanets. What it finds is unclear, but considering it’s the largest and most powerful telescope capable of being launched from Earth, scientists are excited.
A super telescope built to last will pass its first test
Webb is 100 times more powerful than the largest optical telescope ever flown into space: the Hubble Space Telescope. While Hubble orbits the Earth at an altitude of about 354 miles, Webb is about 930,000 miles away. From this standpoint, Webb’s instruments can operate primarily in the infrared portion of the electromagnetic spectrum, relying on sensitivity cameras and a 21.3-foot-diameter mirror. This primary mirror catches infrared light traveling through space and reflects it onto a smaller mirror, which then focuses the light onto the telescope’s instruments for processing and examination.
In one of Webb’s first tests, it targets the TRAPPIST-1 system, a group of seven rocky exoplanets 41 light-years from Earth and three times the diameter of our planet. NASA says Webb’s findings will characterize these planets’ atmospheres and help scientists learn more about planet formation and habitability. Yes, apart from how the exoplanets formed, they are also looking for signs that life might exist.
Will NASA’s James Webb Space Telescope Find Indicators That Could Support Life?
Understanding the TRAPPIST-1 system and other exoplanets could lead to indicators in the atmosphere that could support traces of life in the universe. As the SETI Institute observes, scientists can make a mountain out of this mole of information, even though distant objects appear as one-pixel dots in the images Webb captured. The ultraviolet light from distant planets and stars has been stretched by the expanding universe, but scientists can filter the tiniest dots of that light through a high-tech prism and split it up into a detailed spectrum that can show what’s in a given atmosphere.
Oxygen and other unique markers in an atmosphere can indicate a planet’s biology. The SETI Institute offered such an example: images of the atmospheres of Mars and Venus would show carbon dioxide to observers in other galaxies, while Earth would show not only CO2 but also the accumulation of exhaust gases from billions of years of photosynthesis – ample evidence of life.
The trick, however, is to sort out true and false findings. Scientists can’t hop on a spacecraft to confirm what the Webb telescope sees. To help NASA, several scientists recently published a study in the Proceedings of the National Academy of Sciences saying Webb should look for the presence of methane when looking for extraterrestrial life.
The Webb telescope will have a hard time detecting oxygen, but a prevalence of methane could indicate the biological activity needed to form the chemical compound, the scientists said in a press release announcing the study. Photochemical reactions destroy atmospheric methane, so its appearance in an atmosphere would mean constantly replenishing it to maintain high levels.
Non-biological sources would not be able to produce any significant amount of methane without providing other clues to its origin, such as carbon monoxide. However, the scientists found that non-biological sources cannot readily produce habitable planetary atmospheres rich in methane and carbon dioxide and low in carbon monoxide. So if methane is found in abundance in an atmosphere and other non-biological sources can be ruled out, NASA can begin to build on that evidence.
“One molecule won’t give you the answer – you have to consider the whole context of the planet,” one of the scientists said in the press release. But methane will help eliminate false positives and give NASA and other scientists involved a jump start in determining whether distant planets served — or still serve — as homes for biological, or as we say, “alien” life.
Confidence grows that one day we will see something
The stories the Webb telescope could tell are enticing – so much so that scientists are beginning to feel confident that it’s possible to find conditions for life in the outer reaches of space. Last year, a group of them, led by NASA’s chief scientist, proposed a framework to verify and share with the public the detection of biosignatures outside of Earth.
A biosignature is any feature, element, molecule, substance, or trait that can be used as evidence of past or present life. It must also be something that cannot be made without the presence of life.
As Scientific American reports, the idea is to avoid false positives and false claims by placing results on a scale of one to seven, with a claim moving up the scale as studies corroborate the work. Claims reaching the “final level” would represent robust follow-up observations cementing a connection to life.
Now that the Webb telescope is in space, the joy of watching it at work will lie in the slow resolution of the images it transmits home. Hopefully we’ll see the strongest evidence of how the universe formed, and we’ll also hopefully see signs that habitable worlds are millions of miles away – opening up a whole new set of scientific questions and spurring even more exploration of space .
Did you know that Northrop Grumman helped build Webb? If you are interested in a career exploration room, please click here.