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Infrared Space Observatory

Phase: Past

Launch Date: November 17, 1995

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By May 1998, at the end of its two and a half year operational lifetime, ESA's Infrared Space Observatory (ISO) had made nearly 30,000 scientific observations, employing its four sophisticated and versatile scientific instruments to provide astronomers with diverse data of unprecedented sensitivity at infrared wavelengths from 2.5 to 240 microns.

One target for ISO's Camera was a pair of galaxies know as the Antennae, 60 million light-years away.

Credit: ESA/ISOCAM, Vigroux, L. et. al.

By covering this wavelength range ISO was able to explore regions of the Universe obscured in visible light. Infrared light penetrates the obscuring dust which hides much of the Universe from inspection at visible wavelengths. Light at these wavelengths originates from bodies and material which are cool and distinct from the energetic sources of visible light like the stars. But these cool sources are of fundamental importance.

A rich variety of atomic, ionic, molecular and solid-state spectral features trace the chemistry and evolution of the cold gas and dust from which the stars form, and which they in turn enrich with the heavy elements produced during their nuclear burning and terminal phases. New generations of stars and planets form from the enriched interstellar medium, revealing their presence first through the infrared emission associated with proto-stellar and proto-planetary sources. Most of the star formation which has occurred in the history of the Universe is revealed through the infrared emission of the heated dust clouds which would otherwise hide it from our view.

Last updated: April 16, 2012

Related Links
  • More about ISO -
  • ESA ISO Website -
  • Science@ESA - ISO/Herschel video -