Stars Are Cleaners of the Universe


Stars have been mopping up galaxies and clearing off the dust in massive galaxies, a new study by British researchers has revealed.

According to Cardiff University researchers, the Universe is becoming gradually cleaner as more and more cosmic dust is being mopped up by the formation of stars within galaxies. The study and its results were detailed by researchers at the National Astronomy Meeting in Nottingham.

Researchers looked back 12 billion years in time using the Herschel space telescope and after seven years of work analysing the images from the Herschel telescope, the team of over 100 astronomers have released a large catalogue of the sources of far-infrared radiation in this ‘hidden universe’. Owing to a collection of sensitive instruments, mirrors and filters, the Herschel telescope had the capacity to detect the dust through the far-infrared emission it emits, revealing the existence of stars and galaxies hidden by the dust.

The results showed that stars were forming inside galaxies much faster in the past compared to today, and that this rapid star birth is using up more and more of the cosmic dust that is ubiquitous in the Universe.

Cosmic dust is comprised of tiny solid particles that are found everywhere in space between the stars. The dust and the gas in the universe is the raw material out of which stars and galaxies form.

Though this blanket of material is key to the formation of stars and galaxies, it also acts as a sponge, absorbing almost half of the light emitted by stellar objects and making them impossible to observe with standard optical telescopes.

Dr Loretta Dunne, a co-leader of the project from the School of Physics and Astronomy, said: “Before Herschel we only knew of a few hundred such dusty sources in the distant universe and we could only effectively ‘see’ them in black and white. Herschel, with its five filters, has given us the equivalent of technicolour, and the colour of the galaxy tell us about their distances and temperatures. So we now have half a million galaxies we can use to map out the hidden star formation in the universe.”