Spitzer Space Telescope also is known as Space Infrared Telescope Facility, is one of the most popular space telescopes to have been launched into space till now. Launched in 2003, the mission was planned for 2.5 years with a pre-launch expectation of a period lasting up to 5 years till the liquid helium aboard the spacecraft exhausted. On 15 May 2009, the supply of liquid helium was exhausted and without it most of the instruments were no longer operational as they required low temperatures to work. The mission retired on 30 January 2020. Still, however, the IRAC camera continued to work and gave results until the early 2020s till the Spitzer Warm Mission. In the course of the warm mission, the two shortest wavelength modules of the IRAC camera operated at 30K.
Unlike the other telescopes which are named after other scientists, the story of how this telescope obtained its name is somewhat different from others. A Public contest was organized where people were invited to suggest names for the telescope. The telescope was then named for Lyman Spitzer, who had initially promoted the idea of a space telescope in the 1940s. The 776 million dollar mission was launched on 25 August 2003 from Cape Canaveral at 05:35:39 on the Delta II 7920H rocket.
Warm objects in the far reaches of the Universe do not emit radiation in the visible spectrum of light. Their radiation is observable at the lowest energy levels consisting of Infrared waves whose wavelength is longer than that of the visible spectrum. The Spitzer Space telescope consisted of an infrared camera which enabled it to capture the infrared radiation emitted by distant cosmic objects. Here are some of the discoveries made by Spitzer-
(1) Evidence of the Oldest Galaxy ever known = Spitzer provided the evidence of the oldest and most distant galaxy ever known. With only 1/25th the mass of the Milky Way Galaxy and a relative 1% of its mass, the galaxy has a stellar age of only 40 million years. The name of this galaxy is GN-z11 and was discovered from the data gathered by the teams of Hubble Space Telescope and Spitzer Space Telescope.
(2) An Insight into the Dark Ages = In the dark ages, the light from the very first stars would have been emitted 13 billion years ago. This, however, has resulted in the shifting of the spectrum of visible light towards the infrared spectrum making it practically impossible to observe them from optical and radio telescopes. This puts a conventional limit on the distance one can observe with optical and radio telescopes. However, for Spitzer, this wasn’t much of a problem as it can detect infrared waves providing an exquisite insight into the dark ages of the Universe.
(3) Black Holes = Black Holes emit mostly in the infrared spectrum of light, therefore no observational evidence could be detected from radio telescopes. Spitzer, however, due to its high definition aperture and its high definition images was used by NASA to observe the most distant black holes.
(4) Exoplanet Weather Map = This telescope helped NASA frame one of the first ever maps of the surface of an exoplanet. It was a gas giant named HD 189744b. Although Spitzer was designed mostly for detecting infrared waves in the far vicinity of space, due to the unique innovative minds of NASA, it was able to study the planets beyond the solar system.
Having made observations of the cosmic web for more than 16 years, the journey of the Spitzer telescope met its end on 30 January, 2020 when NASA decided to shut it down. James Webb Space Telescope, who is the successor of the Spitzer Space Telescope, will contribute to the legacy of Spitzer by making more detailed infrared observations of the Universe.
He is a student currently pursuing B.Sc. Mathematics honors from SGTB Khalsa College, Delhi University. He aims at developing multiple skills by taking up exciting projects and wants to a professor in Mathematics.
Shweta, Team SciComm