Entre le chorizogate et la nuit des étoiles, ne vous faites pas avoir par ces fausses images sur les réseaux

Entre le chorizogate et la nuit des étoiles, ne vous faites pas avoir par ces fausses images sur les réseaux

NASA/via REUTERS The “Cosmic Cliffs” of the Carina Nebula are seen in an image divided horizontally by a wavy line between a cloudscape that forms a nebula along the bottom and a comparatively clear top, with data from the James Webb Space Telescope NASA, a revolutionary apparatus designed to peer across the cosmos to the dawn of the universe and launched on July 12, 2022. Dotted on both sides is a star field, displaying countless stars of many sizes. NASA, ESA, CSA, STScI, Webb ERO Production Team/Handout via REUTERS THIS IMAGE SUPPLIED BY A THIRD PARTY. TPX IMAGES OF THE DAY

NASA/via REUTERS

An image of the “cosmic cliffs” taken by the James Webb Telescope and revealed on July 12, 2022

SPACE – This weekend we will have to roll our eyes, both literally and figuratively. Like every year, the month of August offers the ideal conditions for the Night of the Stars. An event whose popularity should double due to the enthusiasm aroused by the James Webb Space Telescope, but which also echoes another news item of the week: the #Chorizogate, as it is already called.

Last week, renowned physicist Etienne Klein posted a photo of a slice of sausage on Twitter, hinting that it was the star Proxima Centauri. A hoax for educational purposes to invite Internet users to be attentive. “ I’m sure if he hadn’t said it was a picture of James Webb, it would have been a lot less successful. “He even confided to the HuffPost.

If the scientist explained and even apologized, the joke had the merit of underlining an important phenomenon: the sharing of false astroimages on social networks. ” It’s so extraordinary, you feel like you have access to another world and you want to believe it. But for all that, certain details must challenge us “, warns the astrophysicist and president of the French society for astronomy and astrophysics, Éric Lagadec, contacted by The HuffPost.

Dunes photo to another

Above all, we must remember that even when we talk about celestial objects millions of kilometers away, there is someone on Earth who took or composed the image in question. “ There are plenty of accounts that feature images with just ‘NASA’ in the credit. This is a first element that should amaze, NASA does not make a single image “, explains Eric Lagadec. For example, in one of the recent images shared on his Instagram account, NASA indicates in the credits “NASA, ESA, CSA and STScI⁣⁣”.

As in any photographic object, we must not forget the post-production and retouching work. This work is also carried out directly by scientists. The Hubble telescope did not take color photos. Then ask the scientists and their computers to combine different shots of the same object, to pass the data and information through the mill, to finally give the stunning colors we know. This colorimetric work done by scientists makes it possible to make sense of what would otherwise be invisible to the human eye.

Finally, be careful with the captions that usually accompany the images presented as unpublished on social networks. If there are many superlatives and few explanations, or even extremely precise figures, again, caution. An image that was broadcast a lot on social networks last weekend was presented as that of a “space vacuum” that would have to be traversed for 732,536,988 years before you could run into anything.

“Obviously it is false, that number of years does not make any sense. We can’t be that precise.warns Eric Lagadec. In this case, the “Empty space” in question was the molecular cloud of Barnard 68. An infrared filter shows that it is not entirely empty.

good accounts make good friends

In general, it must be remembered that an extraordinary discovery, an unprecedented scientific advance will never be made in a simple tweet, but will generate a press conference, scientific articles…” With James Webb somewhere, science is done live. We are just beginning to write scientific articles that will then have to go through a process of verification and peer review. ”, recalls Eric Lagadec.

In this sense, to sharpen the critical eye, it is better to follow Twitter and Instagram accounts that have been certified or recognized for several years for their outreach work. NASA, the European space agency, the southern europe observatorythe CNESor the Instagram account dedicated to the James Webb telescope.

Many well-known astrophotographers, professional or amateur, also regularly share content on social networks.

A little closer to the stars

Above all, if the launch of the James Webb Space Telescope still promises beautiful photos, it can’t do everything. ” James Webb is primarily designed for observing faint, near- and mid-infrared things, not ultra-bright things like a star. says Eric Lagadec. It is, for example, its infrared capability that allowed the JWST to obtain such a precise image of these “cosmic cliffs”. By seeing through gas and dust in particular, it allows you to see just-formed stars.

Above all, stars, even hundreds or even thousands of times larger than our Sun, are located at distances too great to be accurate. The closest star that offers the clearest view of its surface is simply the Sun, remember Éric Lagadec on Twitter.

The scientist indicates as an example that to obtain the image below presenting the star Beltegeuse, 700 light years from us and with a radius a thousand times greater than the sun, it was necessary to use the largest telescope in the world, 40 meters long, located in Chile.

Sometimes astronomers combine the power of two telescopes, making it possible to obtain, as you can see below, a blurred image of the surface of Antares.

Returning to the sausage photo shared by Étienne Klein, the scientist also recalls that this star in question is 50 times smaller than its previously presented cousins ​​and above all that it is a red dwarf, whose surface images of stars are very difficult. get. ” The stars that you can almost get good images of are the red giants that are dying, they are very old stars. So be careful if you are presented with an image of the surface of a red dwarf, which is a star in the process of being born. he adds. No offense to charcuterie lovers.

See also in The HuffPost: We’ve Never Seen a Black Hole This Big


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