NASA has a plan to see the surface of exoplanets within 100 light years

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[EN VIDÉO] Proxima b, the closest exoplanet to us!
It is the only known planet to date orbiting Proxima Centauri, a star located in Alpha Centauri. This system is the closest to our solar system, “only” 4,244 light years away.

This July 29, 2022, the famous place ofEncyclopedia of Extrasolar Planets mentions that the noosphere discovered 5,121 exoplanets since 51 Pegasi B, a discovery then made thanks to the Nobel Prizes of Physical Michel Mayor and Didier Queloz. Futura recently interviewed the creator of this site now world famous, theastronomer French Jean Schneider.

The knowledge of the existence of these exoplanets is an extraordinary advance in the history ofHomo sapiens but it is still very partial because for the most part we only have estimates plenty and distances for these exoplanets, and a few rare spectra that provide a fetus composition of theatmospheres to shorten it.

Of course, we want pictures of the details of these exoplanets, especially if they are potential exo-Earths. Ideally, we would even like to detect biosignatures and even technosignatures there.

That Nasa recently allocated new funds for the study of a spectacular project that could be carried out during the XXIe century for this purpose. The project itself is just in the cards, and there is no question of physically taking it on yet. This is a avatar of a concept proposed in 1979 by a researcher from Stanford University, VR Eshleman: the lens gravitational sun.

Concretely, this means that you take advantage of the fact that the field of gravity of a celestial body deflects light rays like a lens and therefore provides a magnification factor to form images. By standing at a distance Sunso it can be used as gravitational lens to form the image of an exoplanet with a solution record as if we had one giant telescope much larger than those that can be built on Earth due to gravity which deforms one mirror under its own weight.

Scientists like Slava G. Turyshev from Jet Propulsion Laboratory as well as Alexander Madurowicz and Bruce Macintosh from Stanford has therefore published it arXiv and in an article by The Astrophysical Journal for a few years already, where they have developed the concept.

A swarm of telescopes powered by solar sails

Currently, the general ideas on this topic are as follows:

Using directly, as with a telescope, a gravitational lens to form images of an exoplanet, however, we would have rather vague results. It is best to have several instruments flying in a swarm and each observing a part corresponding to a ring ofEinstein for the solar lens, i.e. a deformation of the image of the exoplanet forming a ring, as in the case of certain observations of quasars by means of strong gravitational lensing produced by a cluster of galaxies.

Concretely, this would require sending this swarm to distances between 548 and 900 times the distance from Earth to the Sun, which would make it possible to image exoplanets up to about 100 light years of the Sun. No problem in theory therefore to observe the exoplanets around Proxima Centauri and Trappist 1e.g.

With a single instrument, the mirror of which would be about a meter in diameter, we could obtain images of the surface of these exoplanets with a resolution of the order of a few tens of kilometers.

However, there are several difficulties with this idea. With current propulsion technology, it would take about a century to send the instruments a good distance. At best, we could shorten the period to around 25-30 years, which is reasonable in comparison duration the life of a person involved in this project, using solar sail. The technology in these sails is not yet perfected, although it is reasonably close at hand.

Explanations of the latest concept for a mission to exploit the Sun’s gravitational lensing to image exoplanets. © The Aerospace Corporation

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