Celestial newborns destroy stars

There are not enough stars in the universe and now astronomers think they know why.

Using the Hubble space telescope, they have discovered a distant galaxy in which star formation is itself driving the raw materials for more stars out into space at more than three million kilometres an hour – and in the process slowing future star production.

They believe the discovery could explain why the number of stars in space is lower than expected.

The astronomer Carl Sagan memorably said there were more stars in the universe than grains of sand on all the beaches in the world. That estimate has been refined more recently to 10 stars for every grain – or roughly one hundred thousand million million million, or 100-sextillion, stars. Yet not even this vast figure is enough for modern astronomers.

“We’ve known for about 10 to 15 years that there are not as many stars in the universe as we expect,” says Dr James Geach, of the University of Hertfordshire.


Stars form when clouds of gas are pulled together by the force of gravity. But computer simulations of this process always overestimate the number of stars that astronomers can observe. There should be double or even triple the number of stars in the night sky.

Now, Geach and his colleagues think they have discovered what astronomers have been missing.

They have found a distant galaxy known as a starburst 10-billion light years away that is furiously forming stars at 260 times the rate of our own Milky Way. The torrents of radiation created by the celestial newborns are driving out the remaining gas. As this raw material is blasted away into deep space, the rate of formation will slow and eventually come to a halt.

“We are witnessing the aggressive termination of star formation,” said Geach.

The more stars that form, the more pressure their starlight creates, driving out more gas and preventing rapid star formation.

This is the first time this process has been seen driven solely by the action of star formation itself. Usually it is associated with the action of an active black hole at the centre of a galaxy. Yet there is no sign of an active black hole in this galaxy. In the nearby universe, many galaxies have stopped forming stars altogether. “Something must have cleared the gas out of these galaxies,” said Philip Best, professor of extra-galactic astronomy at the University of Edinburgh, who was not involved in the study.

It is not just individual stars that can fall victim to this process. In its most extreme form, astronomers think it could even blow small galaxies apart, explaining why there are 10 to 100 times fewer dwarf galaxies than expected.

Geach says his team’s observation is “an important new clue in our understanding of the evolution of galaxies”.

The study is published in the journal Nature. – © Guardian News & Media 2014

Subscribe to the M&G for R2 a month

These are unprecedented times, and the role of media to tell and record the story of South Africa as it develops is more important than ever.

The Mail & Guardian is a proud news publisher with roots stretching back 35 years, and we’ve survived right from day one thanks to the support of readers who value fiercely independent journalism that is beholden to no-one. To help us continue for another 35 future years with the same proud values, please consider taking out a subscription.

And for this weekend only, you can become a subscriber by paying just R2 a month for your first three months.

Related stories

Nokia and Nasa to install 4G on the Moon

Installing a wireless network on the Moon is just one step toward establishing a long-term human presence there

Earth’s toughest creatures may be living on the moon

It is unlikely that they will be rescued in time. Even if they survived, they are doomed,”

Nasa spacecraft hurtles toward historic New Year’s flyby

Scientists figured out in 2017 that Ultima Thule is not spherical but possibly elongated in shape. It may even be two objects

Hunt for the octopus from space

Let us entertain the notion — if only for a moment — that cephalopods may be from space. How would we go about testing the hypothesis?

Heigh ho, heigh ho, it’s off to Mars we go

Even if we develop the technology to build pressurised hamster balls, it needs to be recreated on Mars.

How ‘planety’ is Planet Nine?

Evidence of a distant giant planet lurking secretly in our solar system is compelling, according to researchers.
Advertising

Subscribers only

Q&A Sessions: Frank Chikane on the rainbow where colours never...

Reverend Frank Chikane has just completed six years as the chairperson of the Kagiso Trust. He speaks about corruption, his children’s views and how churches can be mobilised

ANC: ‘We’re operating under conditions of anarchy’

In its latest policy documents, the ANC is self-critical and wants ‘consequence management’, yet it’s letting its members off the hook again

More top stories

Covid-19 stems ‘white’ gold rush

The pandemic hit abalone farmers fast and hard. Prices have dropped and backers appear to be losing their appetite for investing in the delicacy

Al-Shabab’s terror in Mozambique

Amid reports of brutal, indiscriminate slaughter, civilians bear the brunt as villages are abandoned and the number of refugees nears half a million

South Africa’s cities opt for clean energy

Efforts to reduce carbon emissions will hinge on the transport sector

How designing ‘green’ buildings can help to combat the climate...

South Africa’s buildings account for 40% of the country’s greenhouse gas emissions. But the City of Johannesburg’s new draft green buildings policy aims to change that
Advertising

press releases

Loading latest Press Releases…