A standard candle is an object of great importance to astronomers because it lets us measure how far away objects are. The type that i study are these therma nuclear super nove explosions of white dwarf stars. They outshine entire galaxies, and you can see them billions and billions of light years away. And they're an exceptional measure of distance in the universe. So there were pioneering studies in the 19 nineties trying to find all of these distant,. some of these distant supernove and to map out the large scale geometry of the universe. And what they discovered was that the universe was expanding, but it was doing so at a faster rate than expected. That's almost as if there were
Melvyn Bragg and guests discuss the abrupt transformation of stars after shining brightly for millions or billions of years, once they lack the fuel to counter the force of gravity. Those like our own star, the Sun, become red giants, expanding outwards and consuming nearby planets, only to collapse into dense white dwarves. The massive stars, up to fifty times the mass of the Sun, burst into supernovas, visible from Earth in daytime, and become incredibly dense neutron stars or black holes. In these moments of collapse, the intense heat and pressure can create all the known elements to form gases and dust which may eventually combine to form new stars, new planets and, as on Earth, new life.
The image above is of the supernova remnant Cassiopeia A, approximately 10,000 light years away, from a once massive star that died in a supernova explosion that was first seen from Earth in 1690
With
Martin Rees
Astronomer Royal, Fellow of Trinity College, Cambridge
Carolin Crawford
Emeritus Member of the Institute of Astronomy and Emeritus Fellow of Emmanuel College, University of Cambridge
And
Mark Sullivan
Professor of Astrophysics at the University of Southampton
Producer: Simon Tillotson