Applications & Uses
Many celestial objects that can’t be seen by humans immediately become visible when using an infrared camera. The picture on the left – of the Trapezium star cluster in the Orion Nebula – was taken by Philip Lucas (Univ. Hertfordshire) and Patrick Roche (Univ. Oxford) with an IR camera at wavelengths roughly twice as long as visible light in the electromagnetic spectrum. (see Chapter 2 – Basic Theory). Without infrared radiation this star cluster would not have been visible, along with other objects such as clouds of particles around stars, infrared galaxies, interstellar molecules, cool stars, brown dwarfs and planets.
On the 25th January 1983, the Infrared Astronomical Satellite (IRAS) – a joint project between the United States (NASA), the United Kingdom (SERC) and the Netherlands (NIVR) – was launched into space to perform a survey of the entire sky at infrared wavelengths. The satellite recorded over 500,000 infrared sources in the sky and made discoveries including six new comets, a disk of dust grains around the star Vega and our galaxy’s core – the Milky Way. Below you can see a spectacular map of all the infrared sources in the sky taken by IRAS. The blue area running across the center of the image is the plane of our galaxy.