Life On Exoplanet Is Possible But We May Not Be Able To Detect It
Using the transit method, scientists can find exoplanets that support life.
Scientists are confident that a path exists to finding life on an exoplanet but say that research is years away from making that path a reality. An article from Universe Today explains that telescopes in development could allow scientists to measure the atmospheric contents of planets in the relatively nearby solar system Trappist-1, thus determining whether or not enough oxygen is on the planet to sustain life.
Exoplanet is the term for a planet that orbits a star outside of Earth’s solar system.
One of the ways stars and planetary systems are observed is called the transit method. When an exoplanet passes in front of its star, it temporarily alters the star’s perceived brightness. That interruption allows scientists to spot celestial objects by observing the effect of a planet’s transit on our view of the cosmos.
As an exoplanet crosses the path of its star, light from the star filters through the planet’s atmosphere. Scientists can theoretically measure the star’s spectrum during these transits. By determining how light is absorbed by the planet’s atmosphere, the atmosphere’s composition can be discovered.
Such measurements would allow scientists to find an exoplanet with life-giving oxygen in its atmosphere. The problem is that telescopes currently in operation cannot accurately capture enough data to make these determinations. That, compounded with the fact that many planetary transits would have to be observed in order to collect sufficient data, makes the task nearly impossible.
However, telescopes being developed now are bigger than ever. They can still only capture small bits of data from starlight passing through exoplanet atmospheres, but it should be enough to determine atmospheric conditions.
These new, large telescopes will still require many transit observations before any conclusions can be drawn. Scientists will have to filter the pertinent data from a considerable amount of noise, meaning they will need a large sample size.
A research team built a model to determine how long it would take to draw these atmospheric conclusions about exoplanets using data observing transit periods. They chose the planets of Trappist-1 as their hypothetical guinea pig.
The planetary system Trappist-1 orbits a Red Dwarf, the smallest and coolest kind of star. The planets orbit their star every four to 12 days. Scientists estimate that thousands of measured transits would be necessary to build up enough data to accurately determine the atmospheric composition of Trappist-1.
That means it would take 16-55 years to get an accurate model of an exoplanet atmosphere from Trappist-1. And that is after a telescope powerful enough to retrieve the data is built.
Some scientists believe that humanity will encounter alien life before we can detect it. Assuming those predictions are incorrect and humanity remains, to its knowledge, alone in the universe, profiling exoplanet atmospheres could be the quickest path to discovering other life in the galaxy.
The timeline for the proposed method is not exactly immediate, but it is decades ahead of interplanetary travel and even further ahead of humanity leaving its own solar system.
If aliens want to contact Earth, they will do so on their terms. For humanity to find extraterrestrial life on its own, the measurement of exoplanet atmospheres may be the fastest path.
