This article was originally published on The conversation (opens in a new tab). The publication contributed the article to Space.com’s Expert Voices: Editorials and Perspectives (opens in a new tab).
Silas Laycock (opens in a new tab)professor of astronomy, UMass Lowell
The James Webb Space Telescope the team has released the first science-grade images (opens in a new tab) of the new telescope. It features the oldest galaxies ever seen by the human eye, evidence of water on a planet 1,000 light years away, and incredible detail showing the birth and death of stars. Webb’s goal is to explore the origins – of the universe, galaxies, stars and life – and the five images released on July 12, 2022 deliver on that promise.
Once the suite of instruments on board all cooled down and ran smoothly (opens in a new tab), astronomers wasted no time in getting Webb to work. Each of the first images contains enough data to produce major scientific results on their own.
Related: NASA’s James Webb Space Telescope Mission: Live Updates
Gallery: The first photos from the James Webb Space Telescope
Webb was designed to collect light across the red to mid-infrared spectrum (opens in a new tab) — the wavelengths of light that are blocked by the earth’s atmosphere. And with its giant mirror and sunshade blocking the infrared emitted by the sun, earth and moon, Webb can produce sharper images never before achieved by any other telescope.
The buzz among professional astronomers like me (opens in a new tab) has been electric ever since Team Webb members shared some tantalizing test footage. And the real pictures are even better than anyone could have hoped for. During the presentation where the first images were published, Webb project scientist Jane Rigby remarked (opens in a new tab), “For Webb, there are no empty skies; everywhere he looks, he sees distant galaxies.” Most of these galaxies were invisible until now.
Ancient galaxies and the early universe
The first Webb image the world saw was of a cluster of galaxies known to astronomers as the SMACS 0723 (opens in a new tab). It is found in the skies of the Southern Hemisphere and is 5.12 billion light-years from Earth.
The detail of the thousands of individual galaxies in the image is stunning. It’s like the universe in high definition, and I encourage you to watch the full resolution image (opens in a new tab) and zoom in to really appreciate the details.
the great white galaxies in the middle of the image belong to the cluster and are of similar age to the Sun and the Earth. Surrounding and interspersed among the galaxy clusters are galaxies that are more distant, but stretched out in dramatic arcs as if seen through a magnifying glass. And that is exactly what is happening. The background galaxies are much farther from Earth but appear magnified, as their light is bent towards Earth by the gravity of the much closer cluster.
In the background you can see faint red galaxies scattered like rubies across the sky. These galaxies are even further away. By measuring the precise attributes of their light, astronomers can tell 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, it does so easily compared to its predecessor, the The Hubble Space Telescope, which launched in 1990. As Rigby joked, “…the Hubble 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 right after the Big Bang.
Understanding planets around other stars
The second revelation was not an image but a spectrum – a distribution of the strength of light at different wavelengths.
Webb pointed his mirror at the exoplanet (opens in a new tab) WASP 96-B – a giant hot gas planet orbiting a star about 1,000 light-years from Earth – as the planet passed in front of its parent star. During this transit, some of the light from the star filtered through the planet’s atmosphere and left a “chemical fingerprint” in the light’s unique spectrum. The specifics of this fingerprint strongly suggest that there is water vapor, clouds, and haze in WASP 96-B’s atmosphere.
As Webb continues to observe smaller planets that could potentially harbor life (opens in a new tab), astronomers expect 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, chemistry that would indicate that the atmosphere is modified by living organisms.
The technical challenge of doing this type of observation, called transit spectroscopy, is enormous, and this first result barely scratches the surface of the scientific content of the spectrum.
Related: The search for extraterrestrial life (reference)
Galactic dances and the lives of stars
The final three images showed the incredible resolution of Webb’s optics as the telescope explored the birth and death of stars.
Webb’s ability to capture mid-infrared light allows his cameras to cut through dense clouds of dust and gas. This ability helped Webb capture spectacular details of the Carina Nebula (opens in a new tab) where the stars are born.
Webb is also perfectly suited to study the end of a star’s life. As stars age, they can swell their outer layers and form nebulae like the stunning South Ring Nebula, photographed by Webb. (opens in a new tab). The image revealed never-before-seen details of the successive waves of material expelled by the dying central star. While Hubble was unable to see through the expanding cloud of dust and debris, Webb provided the first glimpse of the binary star system that formed the nebula.
The last photo from Webb’s release party showed Stephan’s Quintet (opens in a new tab), a group of five galaxies 300 million light-years from Earth, interacting in a cosmic dance. Thanks to Webb’s suite of complementary instruments on board, the telescope can simultaneously pick up the details of individual stars in these galaxies, see the formation of cool stars feeding dust and gas in these galaxies and – most remarkably – Block out stars, gas and dust to see matter swirl around the supermassive black hole at the center of one of the galaxies.
Webb has also captured data on the spectra of hundreds of individual star-forming regions in 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, a project manager for Webb, emotionally described the trip (opens in a new tab)“It was hard to do. It’s hard to put into words how hard it was. There were so many thousands of ways it could have gone wrong.”
But it didn’t go badly. It all came together, and now mankind’s largest space telescope is open for business.
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