{"id":93211,"date":"2025-07-26T04:46:15","date_gmt":"2025-07-26T04:46:15","guid":{"rendered":"https:\/\/www.europesays.com\/us\/93211\/"},"modified":"2025-07-26T04:46:15","modified_gmt":"2025-07-26T04:46:15","slug":"how-can-the-james-webb-space-telescope-see-so-far","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/us\/93211\/","title":{"rendered":"How can the James Webb Space Telescope see so far?"},"content":{"rendered":"

This article was originally published at The Conversation.<\/a> The publication contributed the article to Space.com’s Expert Voices: Op-Ed & Insights<\/a>. <\/p>\n

Imagine a camera so powerful it can see light from galaxies that formed more than 13 billion years ago<\/a>. That\u2019s exactly what NASA\u2019s James Webb Space Telescope is built to do.<\/p>\n

Since it launched in December 2021<\/a>, Webb has been orbiting more than a million miles from Earth, capturing breathtaking images of deep space. But how does it actually work? And how can it see so far? The secret lies in its powerful cameras \u2013 especially ones that don\u2019t see light the way our eyes do.<\/p>\n

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I\u2019m an astrophysicist<\/a> who studies galaxies and supermassive black holes<\/a>, and the Webb telescope is an incredible tool for observing some of the earliest galaxies and black holes in the universe.<\/p>\n

When Webb takes a picture of a distant galaxy, astronomers like me are actually seeing what that galaxy looked like billions of years ago. The light from that galaxy has been traveling across space for the billions of years it takes to reach the telescope\u2019s mirror. It\u2019s like having a time machine that takes snapshots of the early universe.<\/p>\n

By using a giant mirror to collect ancient light, Webb has been discovering new secrets about the universe.<\/p>\n

A telescope that sees heat<\/p>\n

Unlike regular cameras or even the Hubble<\/a> Space Telescope, which take images of visible light, Webb is designed to see a kind of light that\u2019s invisible to your eyes: infrared light<\/a>. Infrared light has longer wavelengths than visible light, which is why our eyes can\u2019t detect it. But with the right instruments, Webb can capture infrared light to study some of the earliest and most distant objects in the universe.<\/p>\n

Breaking space news, the latest updates on rocket launches, skywatching events and more!<\/p>\n

Although the human eye cannot see it, people can detect infrared light as a form of heat using specialized technology, such as infrared cameras or thermal sensors. For example, night-vision goggles use infrared light to detect warm objects in the dark. Webb uses the same idea to study stars, galaxies and planets.<\/p>\n

Why infrared? When visible light from faraway galaxies travels across the universe, it stretches out<\/a>. This is because the universe is expanding<\/a>. That stretching turns visible light into infrared light. So, the most distant galaxies in space don\u2019t shine in visible light anymore \u2013 they glow in faint infrared. That\u2019s the light Webb is built to detect.<\/p>\n

\"A<\/p>\n

A comparison between a thermal image of a garden plot (left) and the actual image, showing the heat differences between the warm asphalt and relatively cooler plants. (Image credit: PeterBruce-Iri via Wikimedia Commons)A golden mirror to gather the faintest glow<\/p>\n

Before the light reaches the cameras, it first has to be collected by the Webb telescope\u2019s enormous golden mirror<\/a>. This mirror is over 21 feet (6.5 meters) wide and made of 18 smaller mirror pieces that fit together like a honeycomb. It\u2019s coated in a thin layer of real gold \u2013 not just to look fancy, but because gold reflects infrared light extremely well.<\/p>\n

The mirror gathers light from deep space and reflects it into the telescope\u2019s instruments. The bigger the mirror<\/a>, the more light it can collect \u2013 and the farther it can see. Webb\u2019s mirror is the largest ever launched into space.<\/p>\n

\"A<\/p>\n

The primary mirror of the James Webb Space Telescope is pristinely polished to ensure the most accurate images. (Image credit: NASA\/MSFC\/David Higginbotham)Inside the cameras: NIRCam and MIRI<\/p>\n

The most important \u201ceyes\u201d of the telescope are two science instruments that act like cameras: NIRCam and MIRI.<\/p>\n

NIRCam stands for near-infrared camera. It\u2019s the primary camera on Webb and takes stunning images of galaxies and stars. It also has a coronagraph<\/a> \u2013 a device that blocks out starlight so it can photograph very faint objects near bright sources, such as planets orbiting bright stars.<\/p>\n

NIRCam works by imaging near-infrared light<\/a>, the type closest to what human eyes can almost see, and splitting it into different wavelengths. This helps scientists learn not just what something looks like but what it\u2019s made of. Different materials in space absorb and emit infrared light at specific wavelengths, creating a kind of unique chemical fingerprint<\/a>. By studying these fingerprints, scientists can uncover the properties of distant stars and galaxies.<\/p>\n

MIRI, or the mid-infrared instrument, detects longer infrared wavelengths<\/a>, which are especially useful for spotting cooler and dustier objects, such as stars that are still forming inside clouds of gas. MIRI can even help find clues about the types of molecules in the atmospheres of planets that might support life<\/a>.<\/p>\n

Both cameras are far more sensitive than the standard cameras used on Earth. NIRCam and MIRI can detect the tiniest amounts of heat from billions of light-years away. If you had Webb\u2019s NIRCam as your eyes, you could see the heat from a bumblebee on the Moon. That\u2019s how sensitive it is.<\/p>\n

\"A<\/p>\n

A person works on the James Webb Space Telescope’s science module that includes its many instruments. (Image credit: Chris Gunn\/NASA via Wikimedia Commons)<\/p>\n

Because Webb is trying to detect faint heat from faraway objects, it needs to keep itself as cold as possible. That\u2019s why it carries a giant sun shield about the size of a tennis court<\/a>. This five-layer sun shield blocks heat from the Sun<\/a>, Earth<\/a> and even the Moon<\/a>, helping Webb stay incredibly cold: around -370 degrees F (-223 degrees C).<\/p>\n

MIRI needs to be even colder. It has its own special refrigerator, called a cryocooler, to keep it chilled to nearly -447 degrees F (-266 degrees C). If Webb were even a little warm, its own heat would drown out the distant signals it\u2019s trying to detect.<\/p>\n

Turning space light into pictures<\/p>\n

Once light reaches the Webb telescope\u2019s cameras, it hits sensors called detectors. These detectors<\/a> don\u2019t capture regular photos like a phone camera. Instead, they convert the incoming infrared light into digital data. That data is then sent back to Earth, where scientists process it into full-color images<\/a>.<\/p>\n

The colors we see in Webb\u2019s pictures aren\u2019t what the camera \u201csees\u201d directly. Because infrared light is invisible, scientists assign colors to different wavelengths to help us understand what\u2019s in the image. These processed images help show the structure, age and composition of galaxies, stars and more.<\/p>\n

By using a giant mirror to collect invisible infrared light and sending it to super-cold cameras, Webb lets us see galaxies that formed just after the universe began.<\/p>\n

This article is republished from The Conversation<\/a> under a Creative Commons license. Read the original article<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"This article was originally published at The Conversation. The publication contributed the article to Space.com’s Expert Voices: Op-Ed…\n","protected":false},"author":3,"featured_media":93212,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[159,783,67,132,68],"class_list":{"0":"post-93211","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-space","8":"tag-science","9":"tag-space","10":"tag-united-states","11":"tag-unitedstates","12":"tag-us"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/114917722292798818","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/93211","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=93211"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/93211\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/93212"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=93211"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=93211"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=93211"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}