6/24/2023 0 Comments Looking back in timeThe farther away an object is, the more the light from it has stretched by the time it reaches us. As the universe expands, it stretches the wavelengths of light along with it, a process called redshift. Infrared is invisible to human eyes, but Webb can capture it in stellar detail. Because space is constantly expanding, the farthest things away from us in the universe are moving away from us, their light growing redder and redder before eventually dropping into the infrared spectrum. It’s similar to what happens to the sound when a siren goes by: The pitch increases as the siren approaches, then decreases as it trails away. When a light source is moving away from a viewer, it gets stretched out, morphing into a longer and longer wavelength, growing redder. Infrared light is often very old light, due to a phenomenon called redshifting. This seems nerdy and technical, but it’s actually what allows Webb to look farther back in time than the Hubble. The Webb is primarily an infrared telescope, so it sees light that’s in a longer wavelength than our eyes can see. The Hubble Space Telescope collects visible light, ultraviolet, and a little bit of infrared. Then there’s the lower-energy light with longer wavelengths: infrared, microwaves, radio. The human eye can see only a narrow band known as visible light, but the universe contains lots and lots of light outside this range, including the higher-frequency, higher-energy forms: ultraviolet light and gamma rays. Light comes in a lot of different varieties. The Webb’s other advantage over Hubble is the type of light it collects. On the right, the same view from the Webb telescope. (Note: These images aren’t perfectly aligned, but you’ll still be able to see the stark difference in detail.) You can also more easily see how some galaxies are warped more clearly, the result of their light passing through gravitational lenses of the galaxies that are closer in the foreground. More of the fainter galaxies in the background are more easily distinguished. On the right, Webb’s view is more detailed. In the below image slider, the Hubble view is on the left. The Hubble Space Telescope previously made similar observations of the same galaxy cluster Webb captured above. You can already see the improvements Webb brings over the Hubble. Overall, that amounts to more than six times the light-collecting area, and when it comes to telescopes, more light collecting equals more detail. Webb’s beautiful, gold-hued mirrors combine for a diameter of 21.3 feet. Hubble’s mirror is an impressive 7.8 feet in diameter. It shows the evolution of the universe over time in its many layers.Īnd it represents a huge improvement over the capabilities of the Hubble Space Telescope, which, until the launch of the Webb, was the largest observatory in space. And not only can Webb capture images of galaxies this old the space telescope can make measurements about what elements those early galaxies are composed of.Īn image like this is akin to a core sample of a sedimentary rock. The very faintest, smallest blips of light in this photos are images of galaxies as they existed more than 13 billion years ago, near the very beginning of time (that light has been traveling through space ever since). Think about that: In every pinprick of sky, there are thousands and thousands of galaxies, at least.Īnd while it appears to us as a flat image, this image reveals the depths of the universe, and is a window through time. The area of sky that grain covers - that’s the size of the area captured in the above image.īut it’s huge in the sense that nearly every object in this image is a galaxy (besides the bright spiky starbursts, which are stars in the foreground). Imagine you are holding out a grain of sand at arm’s length. It’s small in the sense that this image represents only a teensy tiny portion of the night sky. What makes this image so mind-blowing is how small it is, and how large it is, at the same time. The first image released from the Webb space telescope shows a section of the distant universe in detail.
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