The James Webb Space Telescope was designed to find traces of life beyond Earth using spectroscopy, which is one of the goals of its creation. However, scientists have recently had major doubts about the achievability of this goal due to a number of possible obstacles.
James Webb and the search for extraterrestrial life
The recent discovery of two substances in the atmosphere of the planet K2-18b that can be considered biomarkers has led to lengthy discussions about how this news fits with other facts that are known about this world. Later, experts began to discuss the extent to which the results obtained by the space telescope can even be considered proof of the existence of life somewhere.
And then an article by Sara Seager of the Massachusetts Institute of Technology emerged in the discussions on this issue. There, she pointed out a number of problems that could potentially make it impossible to determine the presence of life with this instrument.
In general, the search for traces of extraterrestrial life is officially considered one of the tasks for which the James Webb Space Telescope was created. For this purpose, it has on board at once several of the most advanced spectrographs, which are able to determine the presence of even small amounts of a certain substance in the atmosphere of the exoplanet.
However, in reality, it’s not as simple as it seems. The fact is that absolutely all the light that comes to us from a planet is actually radiation from its star, which has passed through the atmosphere and in which it is thought to find traces of the substances it met on its way.
Problems with spectroscopy
The James Webb Telescope usually determines the chemical composition of exoplanet atmospheres during transits, that is, at times when the planet is between its star and us. The idea that this method is effective is based on the assumption that scientists are able to effectively separate the lines that originated in the Sun from those that the light acquired as it passed through the atmosphere.
However, there are actually some doubts about this. The method works well in the case when the planet orbits around a red dwarf. If the star is much brighter than it, it simply begins to “illuminate” everything, and you can not even notice the planet itself, not that signs of life on it.
In addition, spots on the star make a significant contribution to the distortion of the observations. All this does not apply to the case of K2-18b. The star there quite allows a qualitative spectroscopic analysis. The problem is more with the planet itself.
However, in general about James Webb’s ability to detect biomarkers, it should be recognized that it cannot reliably detect them, despite numerous claims. It is rather able to provide some generalized characterization of the atmospheres of exoplanets. Scientists hope that telescopes actually capable of doing this appear in the next decade.
According to phys.org
