James Webb, the telescope that should allow us to better understand the stars closest to Earth

The weekend science ticket takes an interest on Saturday January 1, 2022 in the James Webb Space Telescope sent into space by the Ariane 5 rocket on Christmas Day. This instrument, the most powerful ever made, will succeed the legendary Hubble.

franceinfo: Alpha Centauri is the closest star system to us, and it is home to an Earth-like planet. The James Webb Space Telescope, launched a week ago, could provide us this year with valuable information on our closest neighbors!

Fiorenza Gracci: Yes, Alpha Centauri are three stars, two large and one small, which gravitate very close to us. The closest of the three – it’s called Proxima by the way – is just 4.3 light-years away. And this year, thanks to the James Webb Space Telescope, launched at Christmas, we hope to learn a little more about these stars and the planets they shelter.

Are they home to planets?

We know since 2016 that there is at least one, around the closest to these stars, Proxima precisely. And it is a small planet, comparable to our Earth. Better, it gravitates at a good distance from its star to be neither too hot nor too cold: it is perhaps habitable. Obviously, this planet, Proxima b, that’s its name, arouses a lot of fantasies. We imagine that she could be an Earth twin. But in reality little is known about her. We know that it is a little heavier than the Earth, we also think that it could have a hot face, and a cold face, perhaps icy, if ever there is water … ignore. Above all, we don’t know if it has an atmosphere. However, an atmosphere is another essential factor in life, of course.

And what will JWST teach us about Proxima b?

So, unfortunately the JWST telescope will not be able to observe Proxima b directly. But he will be able to observe the other stars of the Alpha Centauri system, in particular Alpha Centauri A. It is scheduled for in six months during the 1st cycle of observation of the telescope. And from there, we hope to find information that can be used to learn more about Proxima b and finally to know if it is habitable, if it looks like the Earth or not, if it can shelter life.

Can we imagine going to see these neighboring stars, directly with space probes?

Okay, those are the closest stars. But 4.3 light years is still very far! The most distant probes we have sent are only 0.002 light years away. Going to Alpha Centauri has always been a dream, but it is considered almost impossible. Except for a few years: a project exists. It is called Breakthrough starshot and it consists in sending an armada of probes which would be propelled by solar sails and by a high power laser. The secret is the size of these probes: they would be very small, very light. And so they could be accelerated to a speed close to that of light. But whatever happens the journey should last several decades …


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