Natalie Batalha, a professor of astronomy and astrophysics at the University of California, Santa Cruz, has watched the field of exoplanet science evolve and change since those early discoveries. Batalha served as a co-investigator and scientist on the Kepler mission. Kepler was the first mission capable of finding Earth-sized planets around other stars, and it transformed exoplanet science.
“The first decade of alien planets was a postage stamp collection where you explore planets one by one,” she said. “But then Kepler launched and broke the sensitivity bottleneck. We’re discovering hundreds of planets at once. (James Webb Telescope) will give us this new lens to study diversity. form of exoplanets. We are entering the third era of atmospheric-characteristic exoplanets.”
“One of the key aspects of Webb’s is understanding whether they actually have at least some of the properties of habitability, but it will be,” said Klaus Pontoppidan, Webb project scientist at Space. not a real Earth analogue. The Institute of Telescope Science in Baltimore.
But the planets it will study could be connected to a fascinating idea: What if life happens otherwise beyond Earth? And that’s what the telescope’s successors can study in the decades to come.
“There really is no Planet B for us,” said Jill Tarter, astronomer and former director of the SETI Research Center, who currently holds the Honorary Chair for SETI Research. “Unless we find a way to tackle all the global problems we face here and mitigate those challenges, if we get anywhere, we’re going to create similar problems.” just like we did here on this planet. There’s no way out.”
What is Planet B?
If there is a Planet B out there somewhere, will it be more like Earth, or will it surprise us and be something of a total surprise?
“When we found a Planet B, I wanted it to be an actual twin of the Earth, a planet orbiting a star like this,” said planetary astrophysicist Sara Seager. sun and Earth-like orbit, with a thin atmosphere and oceans and continents”. scientist and professor at the Massachusetts Institute of Technology.
As interested astronomers point out, each telescope has yielded countless unexpected discoveries beyond the ones they intended to observe. Planet B can also be similar.
“I really wish we could find life on something that doesn’t look very much like Earth,” said Nikole Lewis, astrophysicist and assistant professor of astronomy at Cornell University.
“It’s safe for us to say that if it’s like Earth and it smells like Earth, then it could be Earth and therefore have life. That’s not adventurous enough for me, so that’s why. I’d love to throw it out there and really start looking at the atmospheric chemistry and temperatures of planets that might be a little bit bigger than Earth,” she said.
The search for Planet B isn’t black and white: It’s incredibly complex, balancing what we understand about life processes on Earth with what we don’t yet.
On Earth, even in the most extreme environments, life relies on carbon, says Batalha, with liquid water acting as a solvent for biochemical processes and the DNA that encodes genetic information. It is for this reason that life elsewhere may be carbon-based and water-dependent. And hydrogen, oxygen and carbon are very abundant elements in the universe.
Batalha said: “Planet B, based on how we’re looking at it, is a planet with a liquid water surface. “Besides looking for biological features, I think what Webb can do better is looking for signs of a habitable environment.”
It is also possible that if conditions are not favorable elsewhere, life may find a way “to survive in niches and may even find other biochemical pathways under intense impact,” she said.
Perhaps life on another planet can use methanol instead of water for biochemistry, or we will develop different indicators and symbols to detect habitable planets and life on them in the future. hybrid, she said.
The key element that the astronomers we spoke to agree with is keeping an open mind in the search for life – and a reminder to respect what we find.
“If there is a Planet B, it is by definition not ours,” says Batalha. “We talked about the idea of finding habitable worlds as if they were our own. And if a planet is exactly like Earth with the conditions for life, then by definition it’s a planet. the living world, and it’s not ours.”
Recognize a sign of life
“We know how to find that planet, but it has to stop until 2045 or later,” Seager said.
Life, as we understand it, needs energy, fluid and the right temperature, she said. What happens when a latent sign of life is discovered? Seager says: “Finding the sign is amazing – figuring out the next step is crucial.
If it is determined that there is no other way to generate a potential sign of life, then cooperation will be an important aspect, Lewis said. Interactions with chemists, biologists, and people from different fields beyond astronomy and planetary science can determine the way forward.
“I hope that we will be careful and that we will engage with all relevant experts to try to understand if this is the reality, a signature that can only mean life on the planet. this planet, and then hopefully so informed Lewis said.
And it likely won’t be an isolated moment that happens overnight, Batalha said.
“It’s going to be a very long time as we continue to study the biochemistry of the world because any biological feature that we can come up with, you have to show that there’s no one way. no other abiotic (physical, not biological) generates that signal. That would take a long time.”
Searching for life is a journey that includes taking new paths, asking new questions and developing new hypotheses. Then experiments will be put in place to help answer those questions.
Batalha hopes that future telescopes can help scientists complete a planetary census, including how often Earth-like planets appear in the galaxy.
“I think the most important thing is that we keep it going and keep moving forward,” Batalha said.
“Having a scale like this will help us understand where we are in terms of finding life in specific locations, and in terms of the capabilities of missions and technologies that help us in that mission,” Green said. said in a statement.
The seven levels of the scale reflect a step on the path to declaring positive results in the search for life beyond Earth.
“Until now, the public thought there were only two options: it’s life or it’s not life,” said Mary Voytek, head of NASA’s Biology Program. “We needed a better way to share the excitement of our discoveries and demonstrate how each discovery builds on the next, so we could bring the public and scientists to others join the journey.”
Enduring quest for life
Tarter believes that the answer to the search for life may be based on technological anatomy, rather than biological anatomy, because evidence of past or present technology “has the potential to be much less nebulous. much.”
Bioforms can be gases or molecules with signs of life. Technosignatures are signals that can be generated by intelligent life.
They are “something we can observe to show that not only is life on a distant planet, but it is logically authoritative and has built or created something that we have.” observable with an ever-improving ability to look at the universe,” she said.
Since the 1960s, scientists have been listening for radio signals or looking for optical wavelengths of light that indicate someone out there is transmitting something.
If an intelligent civilization “modifies their environment, such as building solar collectors to collect more energy and reuse it for use on the planet’s surface, we observable consequences of using that technology,” Tarter said.
In the future, she hopes for missions that will dig deeper into the planets than the Perseverance rover, which is collecting samples from rocks on Mars. Exploration deeper than 32.8 feet (10 meters) could reveal evidence of ancient technology.
“I think within a century it will do a pretty good job of exploring life, but I really want to keep an open mind,” says Tarter.
If samples collected by Perseverance, which will be returned by future Earth missions in the 2030s, show evidence of ancient biological life on Mars, it raises another question.
Tarter said: “Are we Martians? Early in the solar system, there was a lot of material exchange, a lot of collisions, and the rock fragments that fell off Mars eventually landed on Mars again. down to Earth”. “It is possible that life began somewhere other than Earth.”
An even more interesting possibility is an example of a second origin if biology on Mars is unrelated to us, but an independent origin of life, Tarter said. “That means it happened twice and it’s ubiquitous. It’s amazing. I hope I live to see it.”
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