The James Webb Telescope has proven that it can detect signs of life in space's atmospheres
The components of life are scattered throughout the universe, while Earth is the only place known to have life in the universe. Discovering life far from Earth is a big goal for the community of modern astronomers and planetary scientists.
We are exoplanet scientists and astrobiologists, researchers like us who will be able to measure the chemical composition of the atmospheres of planets orbiting other stars, thanks in large part to next-generation telescopes like James Webb.
Planets outside the solar system are habitable
Life can exist in the solar system where liquid water exists - such as the aquifers of Mars or the oceans of Jupiter's moon Europa. In any case, the search for life in these places is very difficult, as it is difficult to reach them, and monitoring life in them requires sending Space probe and return with physical samples.
Many astronomers believe that there is a great chance of life existing on planets that orbit other stars and that they could be the first places where life will exist.
Computational theories suggest that there are about 300 million potentially habitable planets in the Milky Way alone and many more habitable, Earth-like planets only 30 light-years away from us – our galactic neighbors.
Astronomers have detected more than 5,000 planets outside the solar system, so far, including hundreds of planets that are likely to be habitable for life, using indirect methods that measure the extent of the influence of the planet on its star close to it, these measurements give astronomers information about the masses and size of exoplanets. The solar system, but nothing more than that.
Search for biometrics
To detect life on a distant planet, astrobiologists will study the interaction of starlight with the planet's surface or atmosphere. If the atmosphere or atmosphere has changed, the light will hold a clue called a "biosignature".
For the first half of its existence, Earth enjoyed an oxygen-starved atmosphere, although it hosted single-celled life. The Earth's biosignature was very dim during its early days. This changed abruptly, about 2.4 billion years ago, when a new family of algae evolved.
Algae used the process of photosynthesis, which produces free oxygen - oxygen that is not chemically associated with any other element. At that moment, the oxygen that filled the Earth's atmosphere left a strong and easy-to-observe biomark on the light passing through it.
When light bounces off the surface of a material or passes through a gas, certain wavelengths will be trapped in the gas or surface of materials and not others. This selective confinement of wavelengths of light is the reason objects differ in color.
Leaves are green because chlorophyll is particularly good at absorbing light at the red and blue wavelengths. When light hits the leaf it absorbs the red and blue wavelengths, leaving mainly the green light to bounce back to your eye.
The light lost is determined by the particular composition of the materials the light interacts with, which is why astronomers can understand some things about the composition of an exoplanet's atmosphere or surface by measuring the colors of the light coming from the planet.
This method can be used to identify specific gases in the atmosphere associated with the presence of life - such as oxygen or methane - because these gases leave very specific signatures in the light, and the method can also be used to identify strange colors on the surface of the planet.
On Earth, for example, chlorophyll and other pigmented plants and photosynthetic algae capture specific wavelengths of light.
These pigments produce distinct colors that can be identified using sensitive infrared cameras. If you see this color reflected from the surface of a distant planet, this indicates that chlorophyll may be present.
Telescopes in space and on Earth
It takes a massively powerful telescope to detect these tiny changes in the light from a potentially habitable exoplanet. The only telescope capable of performing work of this kind is the new James Webb Space Telescope.
Since he began his scientific operations in July 2022, James Webb has taken readings on the spectrum of the gas giant planet WASP-96 b outside our solar system. The spectrum showed the presence of water and clouds, but a planet the size and temperature of WASP-96 b is unlikely to harbor life. .
However, this preliminary data shows that James Webb is able to detect subtle chemical signatures in the light from planets outside our solar system.
Next month, Webb will turn its mirrors toward TRAPPIST-1 e, a potentially habitable Earth-sized planet just 39 light-years from Earth.
Webb can look for biosignatures by studying planets as they pass in front of their host stars and picking up starlight passing through a planet's atmosphere, but Webb wasn't designed to search for life, so the telescope is only able to scan a few nearby worlds that are potentially habitable. .
It can only detect changes in atmospheric levels of carbon dioxide, methane and water vapor, and while specific combinations of these gases may suggest life, Webb cannot detect the presence of free oxygen, which is a strong sign of life.
The ideas we're developing for the future will be even more powerful. Space telescopes include plans to block the bright light from the planet's host stars to reveal the bright light reflected from the planet. This idea is similar to using your hand to block sunlight so you can see something well from a distance.
The new generation of space telescopes can use small indoor masks or large outdoor umbrellas like spacecraft to do so, when blocking starlight, it will be easier to study the light reflected from the planet.
There are also three massive ground-based telescopes currently in the works that will be able to search for biosignatures: the Giant Magellan telescope, the Thirty Mete Telescope, and the European Extremely large Telescope.
Each is more powerful than the telescopes currently on Earth, and despite the obstruction of the atmosphere, which distorts starlight, these three telescopes may be able to search for oxygen in the atmospheres of our near worlds.
?Is it biology or geology
Even using the most powerful telescopes in the coming decades, alien biologists will only detect biosignatures from worlds completely altered by life.
Unfortunately, most of the gases produced by life on Earth can come from non-biological processes - cows and volcanoes both emit methane, photosynthesis produces oxygen, but sunlight also produces oxygen when it separates water atoms into oxygen and hydrogen.
There is a great opportunity for astronomers to spot some false positives when looking for life in faraway places. To help rule out these false positives, scientists need to understand the planets of their interest well in order to understand whether geological or atmospheric processes are occurring that could Simulate biometrics.
New studies of planets outside our solar system have the potential to succeed in providing the unique evidence we need to prove the existence of life. The first data from the James Webb Space Telescope gives us a glimpse of the amazing progress that's coming soon.
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