Tuesday 03 April, 2001
Living Universe
Cosmologists are detectives solving one of the biggest mysteries of all, the birth, life and potential death of the universe. But can they ever provide all of the answers?
Discovery highlights the latest in astronomical research that is uncovering the secrets of the universe around us. Here BBC World Service Science Editor, Deborah Cohen, explores the work of scientists and cosmologists who visualise the unimaginable.
Boomerang Project
Martin White is an astronomer who spends his time flying balloons. No, not the type with pretty colours and a basket in which people can stand and view the countryside below.
'They're football stadium-sized structures that fly at 37 kilometres above the earth. They're absolutely enormous'.
A few years ago he and his colleagues sent a balloon to hover over the Antarctic for 10 days. Instead of a basket, it carried an extremely sensitive telescope which took readings in an attempt to provide answers to some of the most fundamental questions of all: what is the shape of the universe and how much matter is there in it?
White is one member of a community of cosmologists who are using highly sophisticated equipment to make sense of the world around us. The questions they're asking are: how old is the universe, how did it get to be like it is today and how long will it last?
Dr White and his team at Harvard University are taking the temperature of the remainder of the 'big bang', the explosion that started the universe. He is doing this by collecting the light that – incredibly – has been travelling through space since shortly after the explosion. It is known as the microwave background radiation and it appeared when matter first became structured. Marcus Chown, astronomer and writer says:
| 'Encoded in this light is an image of the universe, as it was a third of a million years after the big bang. We can get a snapshot of the baby universe.' |
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'And this was a crucial point in the history of our universe when the first structures – the seeds of galaxies like our own Milky Way formed.'
Ever since the microwave background radiation was discovered in 1965, scientists have been trying to bring it into sharp focus. Now with the balloon measurements – known as the Boomerang project – they have achieved it. Marcus Chown adds:
'In this light, from the beginning of time, is everything that cosmologists have been afraid to ask. How old the universe is, how fast it's expanding, what happened in the split second of the universe's existence and what will happen to the universe in the far, far future – it's all there.'
Cosmologists
What cosmologists do is hard for the rest of us to understand. They contemplate the inconceivable. They visualise the unimaginable. They look back in time more than ten billion years to the very start of things. They weigh the entire universe. And they think that nine-tenths of it is missing, and cannot be seen with any existing telescopes.
Some cosmologists collect the data, like Martin White. Others work out what the measurements mean and make models of the universe. The experimentalists have a big range of telescopes to call upon, around the world and in space. Some of these telescopes are updates of the original tubes with lenses, and they pick up the light that means that we can see objects.
Others detect invisible waves, such as the great radio receivers in Arecibo in Puerto Rico and at Jodrell Bank in Cheshire, in the north west of England.
There is the acclaimed Hubble telescope which orbits the earth and collects the visible light before it gets absorbed by the atmosphere. It has given us wonderful pictures of star nurseries in young galaxies, at the time before planets and life as we know it.
| 'It is extraordinary that we have found out so much about the universe – after all we live on a small planet that orbits a rather average star in just one of many spiral galaxies.' |
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In The Beginning…
All civilisations have had their own accounts of how the world began. Many religions state that God created the universe.
In the Old Testament of the Bible it took six days. In the Navajo cosmology this world is the fourth world – our being in the world is seen as the final stage of an ascending series. In the Hindu view, this world is supported by eight elephants and eight snakes.
Now Western science has its version of events: the universe started with a big bang. A massive fireball – and everything that is in the cosmos now, was created then. All the matter – all the galaxies and all the stars and dust within them – came from that one event.
It may seem that cosmologists have all the answers, but that is not the case. The big question is why there are any galaxies in the universe at all. Why aren't the atoms just equally distributed around the cosmos? Why are they clumped together into stars and planets which then hang out with other solar systems to make up galaxies?
The scientists also want to 'see' as far back as possible to the big bang itself. What was matter like before the atoms that we are familiar with were formed?
To recreate this age, they work with the debris that emerges from the few giant particle accelerators that have been constructed on the earth, such as the one at CERN – the European Organisation for Nuclear Research, the world's largest physics centre – just outside Geneva on the Swiss-French border. It is surprising that studying the smallest particles possible will tell them about the origin of the largest object imaginable, the universe itself.
End Of The Universe
There is one question that cosmologists continue to argue over and that is the end of the universe. Will there be one? Or will the universe go on forever or collapse back on itself in a 'big crunch'?
Whatever the outcome, the Earth will not be here to witness the demise – it will have been swallowed by the sun as it ages. Whether the universe ends in a burst of energy or in cold darkness depends on the amount of matter it contains and the gravitational pull of that matter.
The Boomerang project, which Martin White is part of, firmly stated last year that there will not be a big crunch. The cosmos will go on forever, and it will be a cold, dark and miserable place. But that is some 100 billion years away at least, time enough for us to find our way into another universe.
|  |  | | | Boomerang Project |  |
| | The name “Boomerang” project derives from a longer title – Balloon Observations of Millimetric Extragalactic Radiation and Geophysics.
In 1998 the balloon circumnavigated the Antarctic, supporting an extremely sensitive telescope.
The balloon, with a volume of 800,000 cubic metres, carried the two tonne telescope 8,000 km (5, 000 miles) in 10.5 days and landed within 50km (31 miles) of its launch site. |
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