A $10 billion engineering gem, the James Webb Telescope was launched into space nearly nine months ago, and is 1.5 million kilometers from Earth. He delivers absolutely sumptuous images, shots that look like masterpieces. What are they telling us? What do they really teach us?
The James Webb Telescope is exactly 1.5 million kilometers from Earth. There, he observes the universe with his state-of-the-art instruments that see farther and more precisely than anything humanity has ever observed.
He first looked as far as he could and took the deepest image ever taken of the universe: stars with their light rays and galaxies. He also began observing planets to look for possible extraterrestrial life. He has already found water vapor on one of them and CO2 on another. We are clearly not at the end of our surprises.
Journey to the Middle of Webb’s Deep Field
Beyond its celestial beauty, what is it possible to see in this image described as the deepest of the Universe captured to date?
The answer is short, but evocative: thousands of galaxies – including some of the most distant which appear to us for the first time thanks to the NIRCam and MIRI instruments of the James Webb telescope. These two imagers, supported by the Canadian precision guidance detector, which makes it possible to point towards a target with extreme precision, observe the Universe in the near and mid-infrared. These wavelengths pass through clouds of dust and reveal celestial objects that were invisible to other telescopes such as Hubble.
Let’s start by recalling that the photograph corresponds to a very small part of the sky in the southern hemisphere located in the constellation of the Flying Fish. It’s like holding up a little grain of sand between two fingersrecalls André Grandchamps.
The image shows the galaxy cluster SMACS 0723. The galaxies that form this cluster lie towards the center of the image and take on the appearance of hazy whitish circles with some cloudiness around in shades of graynotes the astrophysicist.
They should not be confused with the stars, which are in the foreground of the image.
The celestial bodies which appear with six bluish lines around them are stars of our galaxy which are in our field of vision, between the cluster and usnotes Mr. Grandchamps.
” If these stars of the Milky Way are a few tens of thousands of light-years away, the galaxies of the cluster are much further away at around 4.6 billion light-years from Earth. »
The light that these galaxies send back was therefore emitted shortly before the formation of our planet.
A cluster like a magnifying glass
The sheer mass of the cluster distorts the space-time around it. This gravitational lensing effect amplifies the light emitted by the more distant galaxies behind it. They appear in the image as darker, often stretched orange patches around the cluster.
” You have a nice example of this to the right going to the top of the image. The two whitish dots are two cluster galaxies. The sort of flattened orange ridge in between is a distant galaxy. »
The distance to this orange ridge is not yet known, but several galaxies that lie behind the cluster are between 11 and 13 billion light-years from Earth.
Most small orange galaxies are very far away. The distance of one of them, which is practically not visible in the full image, is estimated at 13.1 billion light-years.
Mr. Grandchamps adds that the very small orange dots are not necessarily the most distant. They can also belong to objects that are inherently small. To know if an object is very far, it must be evaluated.
The Canadian NIRISS instrument (for imager and spectrograph without slit in the near infrared) makes it possible to study celestial objects in order to establish their composition, but also to measure their distance.
By breaking down the light emitted by a celestial object using spectroscopy, it is possible to know its composition and distance. It’s that each chemical element in the Universe has different characteristics, a kind of chemical fingerprint. For example, the characteristics of hydrogen are different from those of helium and lithiumexplains Mr. Grandchamps.
The lens effect can sometimes create a mirror effect. The phenomenon is observable to the left and to the right of the central cluster. It is possible to see each of the galaxies twice, which forms luminous arcs. Additionally, Webb’s image distinctly reveals their bright, star-filled cores, as well as the orange stellar clusters along their edges.
The two flattened orange lines which are above the other, at the bottom of the image, have the same spectral signature, therefore have the same chemical compositions. They probably belong to the same galaxynotes André Grandchamps
It is also possible to see a galaxy speckled with star clusters; it is located near the end of the vertical bluish line of the center star, to the right of a long orange arc. You can see pockets of forming stars reflected from top to bottom.
NASA shares mesmerizing sound of the Southern Ring Nebula and its stars
The cosmos is a visual treat. And the James Webb Telescope delivered breathtaking moments from our galaxy and deep space. But have you ever wondered what the cosmos looks like? NASA has shared a clip that shows what space would look like. The feature, pictured, is the South Ring Nebula captured by the James Webb Telescope, from which the harrowing sonification was rendered
Since being shared, the clip has been played over 20 lakh times and garnered around two lakh likes. NASA, in the caption, explained the mechanism of sonification, the method used to convert visual images into sound. In this method, scientific and visual data are interpreted into audio.
Near-infrared light and mid-infrared light emit color and with color come the frequencies of light under which they fall. The researchers took these light frequencies and converted them directly into sound frequencies. It is obvious that near infrared light has a higher frequency range. In the middle of the image, the notes descend and entirely transform the sound.
Tracing the sound-based image, NASA in the caption wrote: “In the near-infrared image that begins the track, a single star is clearly heard, with louder noise. In the second half of the track, listeners will hear a low note just before a higher note, indicating that two stars have been detected in the mid-infrared. The bottom note represents the reddest star that created this nebula, and the second is the star that appears brighter and larger.