The James Webb Space Telescope team has released the first scientific-quality images of the new telescope. In them are the oldest galaxies ever seen by human eyes, evidence of water on a planet 1,000 light-years away, and incredible details showing the birth and death of stars. Webb’s purpose is to explore the origins — of the universe, galaxies, stars, and life — and the five images published on July 12, 2022 fulfill that promise.
Once the instrument cluster on board cooled down and ran smoothly, the astronomers wasted no time in putting Webb to work. Each of the first images contains enough data to produce important scientific results on their own.
Webb was designed to collect light across the spectrum of the middle infrared and red, wavelengths of light blocked by the Earth’s atmosphere. And with its giant mirror and parasol blocking the infrared emitted by the Sun, Earth, and Moon, Webb can produce images of a sharpness never before achieved by any other telescope.
The buzz between professional astronomers like me has been electric since Webb team members shared tempting test images. And the actual images are even better than anyone could have expected. During the presentation where the first images were published, Webb project scientist Jane Rigby remarked that “for Webb there is no blank sky, everywhere you look, they see distant galaxies.” Most of these galaxies were invisible until now.
This photo shows gravitational lenses and many bright galaxies, but the smaller, dimmer, and less differentiated galaxies in this image are some of the oldest lights that a man-made object has ever detected. NASA / STScI
Ancient galaxies and the early universe
The first Webb image the world saw is of a cluster of galaxies known to astronomers as SMACS 0723. It is in the southern hemisphere sky and is 5.1 billion light-years from Earth.
The detail of the thousands of individual galaxies in the image is impressive. It’s like the high definition universe, and I encourage you to look at the full resolution image and zoom in to really appreciate the details.
The large white galaxies in the center of the image belong to the cluster and are similar in age to the Sun and Earth. Surrounding and interspersed between galaxy clusters are more distant galaxies, but spread out in spectacular arcs as if they were seen through a magnifying glass. And that is exactly what is happening. The background galaxies are much further away from Earth, but they appear to be magnified, as their light is tilted toward Earth by the gravity of the much closer cluster.
In the background faint red galaxies can be seen scattered like rubies in the sky. These galaxies are even further away. By measuring the precise attributes of their light, astronomers can say that they formed more than 13 billion years ago and even determine the abundance of different elements in these early galaxies.
Webb not only produces incredibly sharp images, but it does so so easily compared to its predecessor, the Hubble Space Telescope, which was launched in 1990. As Rigby said, “… Hubble’s extremely deep field took two weeks of exposure, Webb went deeper before breakfast. ” Once Webb makes longer observations that allow him to collect more light from faint stars or galaxies, astronomers will be able to see some of the first stars and galaxies that formed just after the Big Bang.
The James Webb Space Telescope is sensitive enough not only to detect light passing through the atmospheres of distant planets, but also to measure the strength of this light at different wavelengths, as shown here, which may suggest the presence of water or other molecules in an atmosphere. NASA / STScI
Understand the planets around other stars
The second revelation was not of an image but of a spectrum: a rupture of the force of light at different wavelengths.
Webb aimed his mirror at the exoplanet WASP 96-B, a giant hot gas planet orbiting a star about 1,000 light-years from Earth as the planet passed its parent star. During this transit, some of the star’s light filtered through the planet’s atmosphere and left a “chemical footprint” on the unique spectrum of light. The details of this fingerprint strongly suggest that there is water vapor, clouds, and fog in the WASP 96-B atmosphere.
As Webb goes on to observe smaller planets that could harbor life, astronomers hope to detect fingerprints of oxygen, nitrogen, ammonia, and carbon in the form of methane and other hydrocarbons. The goal is to find biosignatures of life, that is, the chemistry that would point to the modification of the atmosphere by living organisms.
The technical challenge of making this type of observation, called traffic spectroscopy, is enormous, and this initial result barely scratches the surface of the scientific content of the spectrum.
The small details seen in this image of the Carina Nebula offer clues as to how stars are born. NASA / STScI
Galactic dances and the life of the stars
The last three images showed the incredible resolution of Webb’s optics as the telescope explored the birth and death of the stars.
Webb’s ability to capture light in the mid-infrared range allows its cameras to cut through dense clouds of dust and gas. This ability helped Webb capture spectacular details of the Carina Nebula where the stars are born.
The Webb telescope can take much higher resolution images than any other space telescope, as shown in this comparison of photos of a dying star with the image of Webb on the left and an image of the Hubble Space Telescope on the right. NASA / STScI
Webb is also well suited for studying the end of a star’s life. As the stars age, they can inflate their outer layers and form nebulae like the impressive southern ring nebula, which was photographed by Webb. The image revealed never-before-seen details of successive waves of matter ejected by the dying central star. Although Hubble could not see through the expanding cloud of dust and debris, Webb offered a first look at the binary star system that formed the nebula.
The last photo of Webb’s departure party showed Stephan’s Quintet, a group of five galaxies 300 million light-years from Earth, interacting in a cosmic dance. Thanks to the set of complementary instruments aboard Webb, the telescope can simultaneously collect details of individual stars in these galaxies, see the cold dust and star formation that feed the gas within these galaxies, and the most remarkable, block the stars, gas and dust. see the material revolving around the supermassive black hole in the center of one of the galaxies.
Webb also captured data on the spectra of hundreds of individual star-forming regions of the Quintet, which will take months to analyze and study.
Webb is the result of 25 years of work by thousands of scientists, engineers and administrators belonging to an international collaboration of space agencies, companies, research centers and universities around the world. John Mather, Webb’s project leader, described the trip emotionally: “That was hard to do. It’s hard to express how hard that was. There were thousands of ways it could have gone wrong.”
But it didn’t go wrong. Everything came together, and now humanity’s largest space telescope is open to business.