On January 30, NASA will bid farewell to its Spitzer Space Telescope. The size of a schoolbus, Spitzer is one of NASA’s most beloved and hardworking telescopes: It launched on August 25, 2003, and its mission has been to study the universe using infrared light. (Space is cold, so detecting even slight variations in heat can be tricky, which is why we’ve needed Spitzer’s specialty skills.) In the last sixteen years Spitzer has revealed the universe to us, including helping scientists understand how galaxies form by revealing cold and impossible to see clumps of gas. It has also helped astronomers better understand star formation because it can see through opaque clouds to reveal activity hidden within them. Later in its mission, Spitzer helped detect the exoplanets around the Trappist 1 star system.

Sadly the mission is now coming to an end. The orbiting telescope has been low on coolant fuel for years, and now it is trailing further and further away from the Earth, making operations more difficult. Still, after nearly fourteen years over its planned mission lifetime, it’s done pretty well for itself. This week we will celebrate its legacy with just a few of the beautiful photos it took during its time in space.

Whenever a telescope goes online for the first time it collects what astronomers call “first light.” This is Spitzer’s first photo, depicting the Elephant's Trunk Nebula. This photo reveals a large stellar nursery which we can see shining bright at the left of the frame. If we looked at this nebula with our eyes or with Hubble, it would look like nothing, like you were staring into the blackness of space, but Spitzer’s infrared capabilities revealed a whole host of protostars, or baby stars that have just been formed and are seen here glowing brightly. Photograph: NASA/JPL-Caltech/W. Reach

In this photo, the telescope peered through what is called the Rho Ophiuci dark cloud. Composed mostly of molecular hydrogen, this is the stuff that turns into stars. The colors in this stunning photo indicate how hot the stars are in their various stages of growth. Some glow hotter and are very young and surrounded by thick clumps of dust, while the brighter blue stars are older and colder. Photograph: NASA/JPL-Caltech/Harvard-Smithsonian CfA

Spitzer didn’t always gaze out into the distant universe, sometimes it looked closer to home: This is a dizzying spectacle of stars at the center of our Milky Way Galaxy. (Our solar system lies around 26,000 light years from the center of the galaxy, and we orbit in one of the outer arms). Without Spitzer this image would be impossible: The thick dust and gas that exists between us and the center of the galaxy blocks visible light. The bright spot at the center is the core of the galaxy, dense with billions and billions of stars, and near the center is our very own supermassive black hole. Photograph: NASA/JPL-Caltech

This image of M82, also known as the cigar galaxy, is 12 million light years away. This photo is a collaboration between Spitzer and SOFIA, another NASA infrared telescope. The waves are magnetic field lines at the center of M82, while the red is hydrogen gas, the yellow is dust, and the gray is visible starlight. Photograph: NASA

This is not Mordor but actually the Perseus molecular cloud, also known as a stellar nursery. Regions like this contain the right conditions to form molecules, especially molecular hydrogen, which is the fuel for new stars. At only 500 light years across, this inferno is a dense collection of dust and gas. Without Spitzer, Perseus would be invisible to us, but infrared reveals these violent beginnings. Photograph: NASA/JPL-Caltech

This legendary spacecraft will be missed but its contributions to astronomy will last for many decades to come. Because of its mission to search out the delicate heat signatures in the cosmos, the spacecraft operates at an astonishingly cold -400 degrees Fahrenheit, allowing the three instruments on board to unveil a new layer of the universe. Photograph: NASA

See more of what Spitzer saw here.

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