By Jonny Lupsha, Wondrium Staff Writer
The James Webb Space Telescope sees the Universe in new ways. It can look at the oldest stars and galaxies and analyze exoplanet atmospheres. An expert explains how it could detect simple alien life.
The launch of the James Webb Space Telescope (JWST) is a once-in-a-generation phenomenon for space exploration. Where Hubble has spent 30 years teaching us about the age of the Universe and showing us celestial bodies in incredible detail, the JWST will use infrared tech to show us another side of the cosmos.
For The Great Courses Daily‘s three-part series about the JWST, we spoke with Dr. Sarah Rugheimer, Glasstone Research Fellow at Oxford University and author of the Audible Audiobook Searching for Extraterrestrial Life, in an exclusive interview. In our first article, Dr. Rugheimer spoke about the differences between Hubble and the JWST, as well as the cause of some of the JWST’s delays and its best working conditions. In our second article, she explained exoplanet research and how the JWST analyzes exoplanet atmospheres.
For our final segment, Dr. Rugheimer discusses how the telescope could detect signs of alien life—which would likely be a little less X-Files and a little more microscopic—and where the best spot is to look.
(Very) Little Green Men
When the public speaks about alien life, we often conjure images in our heads of Hollywood movie monsters: Intelligent creatures with ray guns and incredible tech. However, we rarely consider the more grounded and scientifically likely kind of alien life, which would be on a microbial scale.
Single-celled organisms and other forms of simple life are much more believable than the usual trappings of sci-fi. But why do scientists believe the JWST might find even microbial life? The belief that simple life—like the earliest forms of life on Earth—might exist on other planets finds a bit of support by looking back even before we look up.
“Life started so quickly on Earth,” Dr. Rugheimer said. “In some of our oldest rocks, we already have evidence of life. We have really robust evidence of life dating back 3.5, maybe 3.8 billion years, and this is right after the planet cooled.”
In other words, almost as soon as there could be life on Earth, there was. Had it taken until recently in Earth’s history, that would be cause for more pessimism about foreign microbial life. However, looking at Earth’s timeline transitioning “from no life to life,” as Dr. Rugheimer put it, supports the argument for searching for microbial life elsewhere in the Universe.
Signs of Life
Previously, Dr. Rugheimer explained how the JWST can analyze exoplanets to determine what’s abundant in their atmospheres. Depending on what the JWST sees, certain planets may or may not be more indicative of life.
“If I saw a planet and it [only] had water, CO2 and maybe a tiny touch of methane, I would not be that impressed,” she said. “Water and CO2 are abundant in the Universe and methane can be released by volcanoes in small amounts. We have to look for combinations of gases that couldn’t exist through geology alone—things that biology is the only plausible explanation for because it’s driving the system out of equilibrium.”
Ozone and methane, for example, are a combination that suggest life. Hypothetically, if an alien astronomer looked at Earth with an infrared telescope like the JWST, its best bet for knowing we were here would be detecting ozone and methane in Earth’s atmosphere in addition to habitability signs of water and carbon dioxide.
“Oxygenic photosynthesis uses carbon dioxide, water, and light from the Sun to make the oxygen we breathe. Ozone comes from oxygen; so detecting either would be interesting, and methane is produced in quantities 100 times more by life than by geology.”
Up to this point, we’ve established that the JWST has the right technology and protection for looking at the oldest stars and galaxies in the Universe and that it will also look at some exoplanets, or planets in other star systems. Knowing what to look for that may indicate microbial life in distant regions of the Universe, theorists like Dr. Rugheimer have built models to help observers determine how to look at exoplanets and gather data about their atmospheres.
With all this information, it seems that just one question remains: Where should the JWST look?
In February 2020, NASA announced that the JWST will “seek atmospheres around potentially habitable exoplanets” in the TRAPPIST-1 system, a star system consisting of seven exoplanets 39 light years away that was discovered in 2017. According to Dr. Rugheimer, three of those planets are in the “habitable zone.” NASA defines the habitable zone as “the right orbital distance to be warm enough for liquid water to exist on their surfaces.”
TRAPPIST-1 is a red dwarf star often described as “ultra-cool” in temperature. Dr. Rugheimer had more information on its three potentially habitable planets.
“In fact, because the star is so small, and the planets are so close, if you were standing on the surface of one of the habitable planets, the other two in the night sky would be the size of our Moon,” Dr. Rugheimer said.
“So you would actually be able to see continents and oceans and whatnot on those planets, if they exist. Wouldn’t that be an amazing sight?”
In 30 days, the James Webb Space Telescope will reach its orbit of one million miles from Earth, also known as Lagrange 2, where it will unfold and begin operation. Until then, enthusiasts and scientists the world over are holding their collective breaths.