Infra-Red Astronomy: Seeing the Invisible

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A public lecture by Dr Helen Walker


We see visible light with our eyes and we see wavelengths from blue to red as the rainbow, but this is a very small part of the whole spectrum. When we move beyond the reddest light we can see into the infrared using electronic detectors and a whole new universe opens up, a universe that was previously invisible.

Since the atmosphere absorbs a lot of the infrared light, we launch satellites to work above it and get a clearer view. Nearby clouds of gas and dust which are dark patches against the stellar background in the visible are revealed as sites where new stars are forming, glowing brightly in the infrared. Blank patches of sky are filled with galaxies at the edge of the universe, shining in the infrared because millions of young stars are heating the gas and dust which formed them.

Over the last 30 years our view of the universe has been changed by seeing the invisible using infrared astronomy satellites. This talk will outline some of the discoveries made by infrared satellites such as IRAS, ISO, SPITZER, and HERSCHEL.

Dr Helen Walker has worked with infrared astronomy satellites for 30 years and is currently Test Team Leader for the Mid-Infrared Instrument (MIRI) which will fly on the James Webb Space Telescope.

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