NASA launched its Spitzer Space Telescope into orbit around the Sun on 25 August 2003. Since then, the observatory has been lifting the veil on the wonders of the cosmos, from our own solar system to faraway galaxies, using infrared light.
Managed by NASA's Jet Propulsion Laboratory in Pasadena, California, Spitzer enabled scientists to confirm the presence of seven rocky, Earth-size planets in the TRAPPIST-1 system.
The telescope has also provided weather maps of hot, gaseous exoplanets and revealed a hidden ring around Saturn. It has illuminated hidden collections of dust in a wide variety of locations, including cosmic nebulae, clouds of gas and dust in space, where young stars form, and swirling galaxies.
Spitzer has also investigated some of the universe’s oldest galaxies and stared at the black hole at the centre of the Milky Way.
Spitzer’s primary mission lasted five-and-a-half years and ended when it ran out of the liquid helium coolant necessary to operate two of its three instruments.
But its passive-cooling design has allowed part of its third instrument to continue operating. The mission is scheduled to end on 30 January 2020.
To mark its 'sweet 16', NASA shared 16 images from the mission this week. Here's a selection of the best.
Located 1,500 light years from Earth, the Orion nebula is the brightest spot in the sword of the constellation Orion. Both NASA's Spitzer and Hubble space telescopes contributed to this vibrant image. Four massive stars, collectively called the Trapezium, appear as a yellow smudge near the image center. Visible and ultraviolet data from Hubble appear as swirls of green that indicate the presence of gas heated by intense ultraviolet radiation from the Trapezium’s stars. Less-embedded stars appear as specks of green, and foreground stars as blue spots. Meanwhile, Spitzer’s infrared view exposes carbon-rich molecules called polycyclic aromatic hydrocarbons, shown here as wisps of red and orange. Orange-yellow dots are infant stars deeply embedded in cocoons of dust and gas. Image credit: NASA/JPL-Caltech/STScI
Located 28 light-years from Earth, Messier 104 – also called the Sombrero galaxy or M104 – is notable for its nearly edge-on orientation as seen from our planet. Spitzer observations were the first to reveal the smooth, bright ring of dust (seen in red) circling the galaxy. Spitzer's full view also shows the disk is warped, often the result of a gravitational encounter with another galaxy, and clumpy areas spotted in the far edges of the ring indicate young star-forming regions. Hubble Space Telescope data showing starlight appears blue. Image credit: NASA/JPL-Caltech/STScI
This infrared mosaic offers a stunning view of the Milky Way galaxy's busy center. The pictured region, located in the Sagittarius constellation, is 900 light-years agross and shows hundreds of thousands of mostly old stars amid clouds of glowing dust lit up by younger, more massive stars. Our Sun is located 26,000 light-years away in a more peaceful, spacious neighborhood, out in the galactic suburbs. The bright core in the middle of the image is a dense cluster of stars at the center of the Milky Way, within which lurks a black hole about 4 million times more massive than our Sun. Image credit: NASA/JPL-Caltech/STScI
The Large Magellanic Cloud, a dwarf galaxy located about 160,000 light-years from Earth, looks like a choppy sea of dust in this infrared portrait. The blue color, seen most prominently in the central bar, represents starlight from older stars. The chaotic, bright regions outside this bar are filled with hot, massive stars buried in thick blankets of dust. The red color around these bright regions is from dust heated by stars, while the red dots scattered throughout the picture are either dusty, old stars; young stars newly forming; or more distant galaxies. The greenish clouds contain cooler interstellar gas and molecule-size dust grains illuminated by ambient starlight. Image credit: NASA/JPL-Caltech
This image of Messier 101, also known as the Pinwheel Galaxy or M101, combines data in the infrared, visible, ultraviolet and X-rays from Spitzer and three other NASA space telescopes: Hubble, the Galaxy Evolution Explorer's Far Ultraviolet detector (GALEX) and the Chandra X-Ray Observatory. The galaxy is about 70% larger than our own Milky Way, with a diameter of about 170,000 light-years, and sits at a distance of 21 million light-years from Earth. Image credit: NASA/JPL-Caltech/STScI/CXC
Newborn stars peek out from beneath their blanket of dust in this image of the Rho Ophiuchi nebula. Called "Rho Oph" by astronomers and located about 400 light-years from Earth, it's one of the closest star-forming regions to our own solar system.The youngest stars in this image are surrounded by dusty disks of material from which the stars – and their potential planetary systems – are forming. More evolved stars, which have shed their natal material, are blue. The extended white nebula right of center is a region of the cloud that glows in infrared light due to the heating of dust by bright young stars near the cloud’s right edge. Image credit: NASA/JPL-Caltech/Harvard-Smithsonian CfA
This Spitzer image shows the giant star Zeta Ophiuchi and the bow shock, or shock wave, in front of it. Visible only in infrared light, the bow shock is created by winds that flow from the star, making ripples in the surrounding dust. Located roughly 370 light-years from Earth, Zeta Ophiuchi dwarfs our Sun: It is about six times hotter, eight times wider, 20 times more massive and about 80,000 times as bright. Even at its great distance, it would be one of the brightest stars in the sky were it not largely obscured by dust clouds.
The Pleiades star cluster, also known as the Seven Sisters, is a frequent target for night sky observers. This image from Spitzer zooms in on a few members of the sisterhood. Viewed in the infrared, the stars seem to float on a bed of feathers. The filaments surrounding the stars are dust, and the three colors represent different wavelengths of infrared light. The densest portion of the dust cloud appears in yellow and red, and the more diffuse outskirts appear in green hues. NASA/JPL-Caltech
This infrared image of the galaxy Messier 81, or M81, reveals lanes of dust illuminated by active star formation throughout the galaxy's spiral arms. By moving the slider all the way to the left in order to remove the bluish-white light from stars, you can see the dust lanes more clearly. Located in the northern constellation of Ursa Major (which includes the Big Dipper), M81 is also about 12 million light-years from Earth. Credit: NASA/JPL-Caltech.