Space – This Monday, July 11, the starry sky went into high definition. US President Joe Biden released the first scientific image from the space telescope James Webb. We see a small part of our sky with incredible clarity, showing distant galaxies 13 billion light-years away.
In the coming hours, NASA will release four other images taken by James Webb. But this A simple picture Noteworthy. First, it shows the path traveled since launch Hubble telescope in 1990. Because this particular region of our sky, centered on the galaxy cluster “SMACS 0723” (to which we’ll return), has already been photographed by Hubble. The difference you can see in the video above is stark.
By moving space to HD, James Webb isn’t just going to make pretty pictures. A space telescope will let us To unravel some of the mysteries of the universe. This first photo shows us the campus. To better understand it, The HuffPost Explains you every detail of this photo and its meaning.
A little patch of sky
First, let’s enjoy this wonderful image once again (to see it in very high resolution, it This way)
Space Telescope Science Institute/NASA, ESA, CSA and STScI
You need to start by defining what you see. This square represents the smallest part of the sky. To give you an idea, stretch your hand toward the sky, point your index finger, and imagine that there are grains of sand on it. This is shown in this first image taken by the James Webb Telescope.
Even with a superhero zoom, you can’t see it because this space telescope operates at infrared wavelengths. This allows us to get a better look at galaxies far away from Earth.
Stars “contaminate” the image.
Let’s keep looking at this photo. The most luminous points are star-shaped… precisely the stars of our galaxy. They are very “closer” to us compared to everything else.
All the rest are these dots of various shapes and colors, more or less clear. They are constellations. It contains billions of stars. There are probably hundreds of millions of exoplanets orbiting it.
A long time ago, in a galaxy far, far away
Some galaxies are not far away, while others are very distant. One of James Webb’s main objectives was to bring to life the famous phrase from Star Wars: “A long time ago, in a galaxy far, far away”. Astronomers want to be able to observe galaxies more than 13 billion light-years from Earth.
Because by doing that, we can see the universe after the Big Bang. Why? Because if nothing travels faster than light, its speed will be even less. Let’s say a galaxy is 13 billion light-years away, and James Webb’s photo shows us the light that left this galaxy… 13 billion years ago.
By photographing distant galaxies, telescopes make it possible to go back in time to understand how stars behaved when the universe was very young, a few hundred million years after the Big Bang.
Einstein’s Warping Zoom
James Webb “cheats” the telescope to succeed in getting to the origin of the universe. It uses a “gravitational lens”. This concept was predicted by Albert Einstein and first observed in 1979.
Simply put, enough masses (here, a cluster of large galaxies) can create a kind of magnifying glass-like effect. As a result, it is possible to observe a much more distant galaxy located behind the cluster.
The problem is that it distorts the view we have of the target galaxy (discussed in space-time warping). More details in this article) This video helps to understand the concept better:
That’s why when you look in detail, some galaxies have a weird, curved shape. They have been distorted by gravitational lensing caused by SMACS-0723, a cluster of galaxies less than 5 billion light-years from Earth. Accurate Astronomer Katie Mack. These are very bright white spots in the center of the image. In contrast, the red traces are precisely distant and decaying galaxies. Clearly, the most extended galaxies are the most distant.
The most impressive thing is the weather
Finally, one last important point to fully understand how incredible this photo is is not visible in the image. The James Webb telescope spent 12 hours observing this tiny sky to sharpen. Its predecessor, Hubble, required more than 10 days of observations to produce the same image, but much less clearly. remember Astronomer Jonathan McDowell.
What if James Webb observed this same small sky for 10 days? Resolution doesn’t change, the researcher notes, but image quality does, with increased accuracy and much less blur. Long live the sequel.
See more The HuffPost: James Webb, the space telescope that maps our universe
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