NASA has a new, large telescope. It could find clues to life on far-flung planets
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NASA will launch the largest space telescope ever launched in December. The James Webb Space Telescope can be used to examine planets beyond our solar system in unprecedented detail. It will also check if their atmospheres are indicative of life on Earth.
It's not easy to find life beyond Earth. This telescope will not be able offer solid evidence of alien life. Some researchers believe that the telescope may be able to detect signs of life on Earth-sized worlds, which have so far been elusive.
New telescopes and cosmic ambitions
Over three decades ago, searching for signs of life was not part of the job description of the James Webb Space Telescope. It was named after an ex-NASA administrator.
Back then, there was no way to know if any planets were orbiting distant stars. Scientists wanted a telescope capable of capturing light from the first galaxies within the universe.
The $10 billion instrument was so complicated and time-consuming to build, it has led to a new scientific field. This is the study of exoplanets, planets outside our solar system. This telescope's power is a boon for the new generation of astronomers.
Laura Kreidberg (German astronomer, Max Planck Institute for Astronomy) says that James Webb was first discussed in the 1990s. She is an elementary school student. She points out that the 1995 discovery of a Sun-like star around a planet was the first time such a planet was discovered.
Scientists have discovered thousands of planets since then. Kreidberg says that 25 years ago, the first planet discovered around a star was found. "Now we know that almost every star has at least one planet," Kreidberg said.
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James Webb's launch will revolutionize our ability to study these distant worlds. It's been hard to determine what distant planets look like beyond basic information such as their mass and distance from the star they orbit.
Scientists don't usually see the planets. Researchers instead detect planets indirectly. Researchers can use indirect methods to detect planets, such as measuring how gravity of a planet causes a star to wobble or watching if a star dims due to a planet passing in front of it.
It is possible to get a glimpse into the atmosphere of a planet by using a telescope such as Hubble to examine the starlight passing through it.
Lisa Kaltenegger (an astronomer at Cornell University) says that "we can do this analysis right away for the big, hot, planets with lots of gas so the light shines through," and her research focuses on planets around other stars.
She says, "But for small planets such as the Earth's with just a bit of atmosphere, we need more light to do that same thing."
James Webb is here to help.
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Looking for biosignatures in distant worlds?
The telescope's 21-foot-wide light-collecting mirror will allow scientists to analyze the chemical composition of small rocky planets' atmospheres.
The James Webb Space Telescope can find signs of life on rocky worlds.
This is important because scientists expect to see tell-tale combinations between different gases on any planet that has life as we know.
Nikole Lewis, an astronomer at Cornell University, says that "The James Webb Space Telescope does possess the capability to measure these key biosignatures." It's possible for the James Webb Space Telescope, to detect signs of life on rocky worlds.
James Webb will be studying a fascinating planetary system located 40 light years from Earth. TRAPPIST-1 is a small cool star. Seven planets of Earth size orbit the star. Three of them orbit in the area where water should be liquid.
Lewis says, "It's a perfect target for James Webb Space Telescope."
Lewis says James Webb should be capable of revealing whether any of these planets is actually surrounded or not by air. "And then, we'll go from there-ok, what's that air made of?" Is the air the same for planets close to the star, or planets far from the star?
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Alien life? Not so fast
Lewis believes that scientists will debate the meaning of any potential atmospheric signs of life found by the telescope. The public may end up with a wrong understanding.
Lewis says, "As careful scientists we are in trying to present findings, people immediately assume we have found aliens when they hear words like 'habitable zones plus water'." "We have to be very careful."
It is extremely difficult to find subtle combinations of gases that could indicate life on other planets, especially with a telescope not designed for this task.
Some astronomers believe it is a stretch for James Webb to be able find signs of alien life, if there are any.
Kreidberg says that the telescope should be able to determine which gas dominates an atmosphere. However, when it comes to combinations of gases, especially those with low abundances or weak spectral features, it can be very difficult.
Because of the information this telescope will reveal about other planets, large and small, she is still excited for James Webb’s launch later in the year. Kreidberg is optimistic that other space telescopes that were designed from the beginning to search for signs of life on Earth-like planets will soon be built.
