The Webb telescope has achieved a remarkable feat—capturing an image of a planet beyond our solar system. The exoplanet, Epsilon Indi Ab, is located 12 light-years away, which is cosmically close despite being trillions of miles distant. This world is somewhat similar to Jupiter but is twice as massive.
"This discovery is exciting because the planet is quite similar to Jupiter—it is a little warmer and is more massive, but is more similar to Jupiter than any other planet that has been imaged so far," said Elisabeth Matthews, a scientist at the Max Planck Institute for Astronomy who led the research. The findings were published in a science journal.
The Webb telescope, the most powerful ever built, used a coronagraph to capture the faint light from this far-off planet. A coronagraph blocks light from a specific star while capturing an image, allowing light from the nearby exoplanet to reach Webb.
"Directly detecting planets around other stars is no easy feat," according to the space agency. "Even the nearest stars are still so far away that their planets appear to be separated by a fraction of the width of a human hair held at arm’s length. At these tiny angular scales, the planet’s faint light is lost in the glare of its host star when trying to observe it."
Epsilon Indi Ab, with temperatures of around 35 degrees Fahrenheit (2 degrees Celsius), is one of the coldest planets ever directly imaged. Unlike other gas giants found in the cosmos, which can be scorching hot, this world is just 180 degrees Fahrenheit warmer than our solar system's Jupiter. This allows planetary scientists to research a large, gas exoplanet somewhat like ours. It could be quite cloudy and may contain familiar gases like methane, carbon monoxide, and carbon dioxide.
"Astronomers have been imagining planets in this system for decades; fictional planets orbiting Epsilon Indi have been the sites of sci-fi episodes, novels, and video games like Elite," said Caroline Morley, an exoplanet researcher at the University of Texas at Austin who worked on the new study. "It's exciting to actually see a planet there ourselves, and begin to measure its properties."
The Webb telescope—a scientific collaboration between NASA, the ESA, and the Canadian Space Agency—is designed to peer into the deepest cosmos and reveal new insights about the early universe. But it's also peering at exoplanets in our galaxy, along with the stars and galaxies that formed over 13 billion years ago, just a few hundred million years after the Big Bang.
Webb's mirror, which captures light, is over 21 feet across. That's over two-and-a-half times larger than the Hubble mirror. Capturing more light allows Webb to see more distant, ancient objects. 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 than visible light, so the light waves more efficiently slip through cosmic dust; 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.
The Webb telescope carries instruments 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 they gas giants or smaller rocky worlds. Webb looks at exoplanets in the infrared. Who knows what we'll find?
"We might learn things we never thought about," said Mercedes López-Morales, an exoplanet researcher and astrophysicist at the Center for Astrophysics.
Already, astronomers have successfully found intriguing chemical reactions on a distant exoplanet and have started looking at one of the most anticipated places in the cosmos: the rocky, Earth-sized planets of the TRAPPIST-1 system.
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