It’s just over two years since the European Space Agency’s Herschel space telescope was launched in May of 2009. At 3.5 metres this telescope has the largest single mirror ever built for a space telescope; it is used to collect long-wavelength radiation from some of the coldest and most distant objects in the Universe. This infrared radiation is hard to detect from the earth, because the atmosphere blocks out most of it, and the atmosphere itself causes another problem. It produces infrared, often putting out more infrared radiation than the object in space being observed. But by moving the observatory into space both these problems are solved.
Herschel is run like a terrestrial observatory – interested scientists can apply for time on the telescope – the current deadline for open time proposals is September 15 of this year, although you would need to check against the current list of proposals to avoid duplication.
The Herschel space telescope is named for the great astronomer William Herschel, born in Germany in 1738, he moved to Bath, England when he was 18 to work as a musician. Later he taught music, composed and conducted. He is known as the discoverer of Uranus in 1781, but he also discovered infrared radiation – although he called it calorific rays.
The infrared radiation that the space telescope looks at is important because a lot of the most interesting things going on in our galaxy and beyond occur within or behind vast clouds of gas and dust. Our view is blocked because the dust grains are very effective at scattering or absorbing visible light, but longer infrared wavelengths can get through the dust.
Credits: ESA & SPIRE consortium & HerMES consortium
Recent work from Herschel space observatory has looked through the Lockman hole – a region in the constellation Ursa Major that is empty of too much local cosmic dust. In this region a detailed map of very distant galaxies was produced and this has shown that galaxies seem to require less mass than expected in order to start producing massive numbers of stars. At the heart of this is that mysterious matter – dark matter – that is responsible for most of the mass of galaxies, yet is not luminous or easily detectable. Dark matter is involved in how galaxies are born – current models start with large amounts of dark matter that then drag in ordinary atoms and when enough atoms accumulate, a ‘starburst’ is ignited – this is when stars form at rates of one hundred to one thousand times faster than our own galaxy does now. The dusty galaxies seen by Herschel are remote and smaller than expected – less than 1/10th of the size predicted for a galaxy to be able form large numbers of stars. Models of galaxy formation will now need to be adjusted to reflect these new results, and we can take another step closer to understanding how galaxies – including our own –came into being.
Read more at the ESA site