Flamsteed AS Chris Lintott

Flamsteed Astronomy Society

“Who, what and when — Progress in the BIG questions in astronomy” by Dr Chris Lintott, April 7, 2008

Thanks to his work on BBC’s ‘Sky at Night’ programme Dr Chris Lintott is now one of the most familiar faces in British astronomy. He is a junior research fellow at Somerville College Oxford and co-author of “Bang!” with Sir Patrick Moore and Dr Brian May.

Chris spoke with passion and energy about ‘progress in the BIG questions in astronomy’. His presentation was very engaging with excellent visuals, and much enjoyed by all present. He began by reflecting that astronomy is now enjoying a 10-year golden age quite equivalent to the boom in the exploration of space in the 1960s and 70s. Our understanding on the ‘big’ questions has come on in leaps and bounds:

When did the Universe begin?

13.7 billion years ago (+/- 100m years) apparently! Chris ran through the development of today’s Big Bang Cosmology starting with Olbers’ Paradox, via Einstein’s General Theory of Relativity with its mistaken fudge factor for a static universe, on to Slipher’s and Hubble’s discovery of the expansion, the abundance of elements, and the CMB Cosmic Microwave Background. We now believe we know the age of the Universe with better precision than the age of the Earth!

How big is the Universe?

We can only see as far as permitted by the time available for light to have travelled since the Big Bang — 13.7 billion light-years. But we now think this ‘visible’ universe may only be one-millionth of the whole.

What is the Universe made of?

75 years ago, Fritz Zwicky was the first to suggest there was far more to the Universe than meets the eye (literally). From his studies of the Coma galaxy cluster Zwicky inferred that there must be 6 times more invisible ‘ dark matter’ present than ordinary ‘baryonic’ matter. Evidence has steadily grown that this amount of unseen matter must indeed be present. Either that, or our understanding of the way gravity works (Newton’s Law) is incomplete ( MOND theory). So far, despite huge investments in research, nobody has been able directly to detect dark matter particles, but scientists are very reluctant indeed to question Newton’s Laws. Watch this space!

Who is out there?

The question of life elsewhere in the Universe, especially intelligent life, is one of eternal fascination and utmost importance. Chris defines ‘intelligent life’ as one where astronomers have developed. Our road-map in the search for extra-terrestrial intelligence ( SETI) since 1960 has been the ‘ Drake equation’. The equation lists the factors which should determine our ability to detect intelligent life elsewhere in the Universe. Chris described how our knowledge about some of these factors has been transformed in just the last 10 years.

First, star formation: we now have observations of many regions of star formation and spectroscopic analysis is adding daily to our understanding of the mechanisms involved.

Second, planet formation: the discovery of new ‘ exoplanets’ outside our solar system is now almost daily headline news. The count is over 300 and rising. It is clear that planets are common. Earth-sized planets at present are below the threshold of our capability to detect, but this is changing as we speak.

Although developing fast, our understanding of the conditions for life on a planet is still hazy. On Earth in the last 50 years we have found life in places previously thought totally unsuitable. On Mars however, we have so far failed to detect any compelling evidence despite a century or more of expectation.

A golden age indeed.

MRD