The James Webb Space Telescope just looked back in time a whopping 13.4 billion years. You read that right.
And doing so allowed scientists to find the earliest galaxies humanity has ever seen (so far, that is). These galaxies, containing countless stars, were created soon after the universe was born.
"For the first time, we have discovered galaxies only 350 million years after the big bang, and we can be absolutely confident of their fantastic distances," Brant Robertson, an astrophysicist at the University of California Santa Cruz who worked on the research, said in a statement(opens in a new tab). "To find these early galaxies in such stunningly beautiful images is a special experience."
To capture the profoundly faint light from these galaxies, the astronomical team trained the Webb telescope – the most powerful space observatory ever built – on a relatively tiny patch of sky. But they looked for many hours, catching lots of detail. "The image is only the size a human appears when viewed from a mile away," the European Space Agency,(opens in a new tab) which runs the telescope with NASA and the Canadian Space Agency, explained. "However, it teems with nearly 100,000 galaxies, each caught at some moment in their history, billions of years in the past."
"To find these early galaxies in such stunningly beautiful images is a special experience."
In the image below, there are four galaxies representing the faintest light ever captured by astronomers. They are fuzzy dots – not grandiose spiral galaxies – because of their profound distance. And, crucially, they are reddish. That’s because the universe is expanding, so this ancient light is stretched out, and longer wavelengths of light appear red (this is called “redshift”(opens in a new tab)).
Scientists used a highly specialized instrument on the Webb telescope, called the Near-Infrared Spectrograph, or NIRSpec(opens in a new tab), to determine the age of these distant objects. A spectrometer acts a bit like a prism, separating light into different colors or parts, ultimately allowing astronomers to dissect the physical properties and composition of the object they're viewing, like a galaxy or planet. In this case, researchers looked for specific patterns in the light caused by the extreme redshift, allowing them to confirm how old the light is — and thus, how old the galaxies are.
"These are by far the faintest infrared spectra ever taken," astronomer Stefano Carniani from Scuola Normale Superiore in Italy, who also worked on the research, said in a statement.
This faint light detection isn’t simply a scientific achievement. It's confirmation that some 13.4 billion years ago, millions of stars, which would help manufacture the elements necessary to eventually make the first planets(opens in a new tab), illuminated the cosmos.
You can expect more unprecedented views, and insight, into the cosmos. The JWST Advanced Deep Extragalactic Survey, or JADES, which is the Webb project peering into the early universe, will spend hundreds of hours looking into deep space in 2023.
The Webb telescope's powerful abilities
The Webb telescope is designed to peer into the deepest cosmos and reveal unprecedented insights about the early universe. But it's also peering at intriguing planets in our galaxy, and even the planets in our solar system.
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Here's how Webb is achieving unparalleled things, and likely will for decades:
Giant mirror: Webb's mirror, which captures light, is over 21 feet across. That's over two and a half times larger than the Hubble Space Telescope's mirror. Capturing more light allows Webb to see more distant, ancient objects. As described above, the telescope is peering at stars and galaxies that formed over 13 billion years ago, just a few hundred million years after the Big Bang.
"We're going to see the very first stars and galaxies that ever formed," Jean Creighton, an astronomer and the director of the Manfred Olson Planetarium at the University of Wisconsin–Milwaukee, told Mashable in 2021.
Infrared view: Unlike Hubble, which largely views light that's visible to us, Webb is primarily an infrared telescope, meaning it views light in the infrared spectrum. This allows us to see far more of the universe. Infrared has longer wavelengths(opens in a new tab) than visible light, so the light waves more efficiently slip through cosmic clouds; the light doesn't as often collide with and get scattered by these densely packed particles. Ultimately, Webb's infrared eyesight can penetrate places Hubble can't.
"It lifts the veil," said Creighton.
Peering into distant exoplanets: The Webb telescope carries specialized equipment called spectrometers(opens in a new tab) that will revolutionize our understanding of these far-off worlds. The instruments can decipher what molecules (such as water, carbon dioxide, and methane) exist in the atmospheres of distant exoplanets — be it gas giants or smaller rocky worlds. Webb will look at exoplanets in the Milky Way galaxy. Who knows what we'll find.
"We might learn things we never thought about," Mercedes López-Morales, an exoplanet researcher and astrophysicist at the Center for Astrophysics-Harvard & Smithsonian(opens in a new tab), told Mashable in 2021.
Already, astronomers have successfully found intriguing chemical reactions on a planet 700 light-years away, and the observatory has started looking at one of the most anticipated places in the cosmos: the rocky, Earth-sized planets of the TRAPPIST solar system.
