Although we haven’t discovered life on Mars yet, one researcher thinks that within the next 25 years we may be able to find signs of it on planets outside of our solar system.
These words were spoken by ETH Zurich astrophysicist Sasha Quanz during the recent opening of the university’s new Center for the Origin and Prevalence of Life.
At a press briefing on September 2, Quanz described the technological initiatives that are currently under way that might allow researchers to finally resolve the question of whether or not we are alone in the universe.
During the briefing, Quanz stated, “In 1995, my colleague [and Noble Prize laureate Didier Queloz] discovered the first planet outside of our solar system.” As of today, we are aware of more than 5,000 exoplanets, and we find new ones every day.”
Given that astronomers think each of the more than 100 billion stars in the Milky Way galaxy has at least one companion planet, there are undoubtedly many more exoplanets still to be found. This makes a huge number of exoplanets. According to Quanz, many of them are like Earth and are at a distance from their host stars that makes it possible for conditions needed for life, like liquid water, to exist.
According to Quanz, the existence of atmospheres on these terrestrial planets and their composition are unknown. “We must look into these planets’ atmospheres. To be able to photograph these planets, we need an observational strategy.
The briefing happened just one day after the James Webb Space Telescope team released the first direct image of an exoplanet orbiting a distant star. The image was of HIP 65426 b, a huge gas giant that is 12 times the size of Jupiter and is 100 sun-Earth distances from its parent star.
The James Webb Space Telescope has already made a number of advances in exoplanet research, including the detection of carbon dioxide and water in the atmospheres of several of them. The James Webb Space Telescope was not designed to study exoplanets but rather to search for the universe’s oldest stars. Although Webb is the most powerful observatory ever launched into space, Quanz warns that it is not quite powerful enough to see the much smaller, Earth-like planets that orbit their stars at closer ranges where liquid water can exist.
Quanz declared, “[The HIP 65426] system is a very special system.” The planet is a gas giant that orbits its star very far away. When it comes to taking pictures of planets, Webb is capable of doing this. The small planets won’t be accessible to us. “Webb lacks the strength to accomplish that.
New instruments are already being created to make up for this weakness in the James Webb Space Telescope’s capabilities. The mid-infrared ELT imager and spectrograph (METIS), a pioneering instrument for the Extremely Large Telescope, is being developed by Quanz and his team (ELT). The ELT, which is currently being constructed by the European Southern Observatory in Chile, will have a 130-foot-wide (40-meter) mirror when it is finished, making it the largest optical telescope in the world.
The main objective of the instrument, according to Quanz, is to capture the first image of a terrestrial planet, possibly similar to Earth, orbiting one of the nearest stars. But in the long run, we want to investigate the atmospheres of dozens of terrestrial exoplanets in addition to a handful of stars.
Quanz acknowledges that it’s still possible for the METIS instrument to miss finding evidence of life on an extrasolar planet. Earth’s atmosphere interferes with ground-based telescopes like ELT, skewing measurements of the chemistry of the atmospheres surrounding other planets. The big question will need to be addressed by a completely new mission because Webb is not quite up to the task. According to Quanz, that mission is already being discussed by the European Space Agency (ESA). LIFE, which stands for “Large Interferometer for Exoplanets,” is the name of the mission. It was first thought of in 2017, but research is still in its early stages and the mission has not yet been approved or funded.
Quanz said, “The mission is being looked at as a possible candidate for a large mission in the ESA science program in the future.”
The space telescope would look at a lot of interesting exoplanets to see if their atmospheres have any molecules that could have been made by living things.
Quanz said that the new ETH Zurich center will help prepare for this upcoming mission and help us learn more about how the chemistry of life affects the environments and atmospheres of planets.
To help us prioritize target stars and target planets, Quantz said, “We need to gain a deeper understanding of the possible components of life, the pathways and timescales of chemical reactions, and the external conditions.” Because there may be other processes that could result in the creation of the gases in these atmospheres, it is important to ascertain whether the traces of life are in fact bioindicators.
Quantz’s goal of finding life outside of the solar system in 25 years is not “unrealistic,” he said, even though it is a big goal.
“No assurance of success exists. However, there are other things we’ll discover along the way, “said he.
