Post by cherise on Feb 4, 2006 19:56:01 GMT -5
The darkness inside of everything
February 4, 2006
Studies of supernovas and the developing concept of dark energy have thrown theories on the nature of the universe and its future into free-fall, writes Katherine Kizilos.
IN 1998, AN ASTRONOMER working with Brian Schmidt from the Australian National University published a paper about supernovas that, for those who understood it, revealed the universe to be more unfathomable than had previously been imagined.
The supernova research led to a strange conclusion: that the universe is filled with a dark energy that is causing galaxies to move away from each other at an accelerated rate. It is now believed that dark energy makes up 73 per cent of the universe; the twist is that nobody knows what dark energy is. Not so long ago, physicists speculated that an all-encompassing Theory of Everything, describing the universe and all its wonders, was within mankind's reach. That is looking less likely now.
When Schmidt began searching the skies for supernovas he had no clue that their behaviour would lead to revelations about dark energy. Supernovas are spectacular eruptions that occur at the end of a star's life. These massive blazes, which in some cases can rival the brightness of the surrounding galaxy, are rare events, and useful to astronomers.
They use them as signposts (standard candles is the astronomical term) which help them calculate the size and age of the universe. Schmidt and his team were searching for type Ia supernovas, which burn with an intense light for about 100 years before their final collapse.
"We can see them three-quarters of the way across the universe," says Schmidt, "so they allow us to look back in time." The oldest supernova that has been observed is 9 billion light years from earth, which means that it exploded 9 billion years ago. (The universe is now believed to be about 13.7 billion years old, with a 5 per cent margin for error.) The team was searching for supernovas as a way of determining how the expansion of the universe has changed over time.
The idea here is that geometry is destiny. It was believed that if the shape of the universe were known, astrophysicists would be able to predict how it would eventually end. If the shape was a plane, say, or an open curve - like a wide-mouthed letter C in which the two ends point away from each other - then the universe could, theoretically at least, expand forever. But if space was found to curve inwards, the universe could end in a final crunch; an event Schmidt calls the "gnaB giB", which is Big Bang backwards and an example of the little jokes astronomers like to tell.
February 4, 2006
Studies of supernovas and the developing concept of dark energy have thrown theories on the nature of the universe and its future into free-fall, writes Katherine Kizilos.
IN 1998, AN ASTRONOMER working with Brian Schmidt from the Australian National University published a paper about supernovas that, for those who understood it, revealed the universe to be more unfathomable than had previously been imagined.
The supernova research led to a strange conclusion: that the universe is filled with a dark energy that is causing galaxies to move away from each other at an accelerated rate. It is now believed that dark energy makes up 73 per cent of the universe; the twist is that nobody knows what dark energy is. Not so long ago, physicists speculated that an all-encompassing Theory of Everything, describing the universe and all its wonders, was within mankind's reach. That is looking less likely now.
When Schmidt began searching the skies for supernovas he had no clue that their behaviour would lead to revelations about dark energy. Supernovas are spectacular eruptions that occur at the end of a star's life. These massive blazes, which in some cases can rival the brightness of the surrounding galaxy, are rare events, and useful to astronomers.
They use them as signposts (standard candles is the astronomical term) which help them calculate the size and age of the universe. Schmidt and his team were searching for type Ia supernovas, which burn with an intense light for about 100 years before their final collapse.
"We can see them three-quarters of the way across the universe," says Schmidt, "so they allow us to look back in time." The oldest supernova that has been observed is 9 billion light years from earth, which means that it exploded 9 billion years ago. (The universe is now believed to be about 13.7 billion years old, with a 5 per cent margin for error.) The team was searching for supernovas as a way of determining how the expansion of the universe has changed over time.
The idea here is that geometry is destiny. It was believed that if the shape of the universe were known, astrophysicists would be able to predict how it would eventually end. If the shape was a plane, say, or an open curve - like a wide-mouthed letter C in which the two ends point away from each other - then the universe could, theoretically at least, expand forever. But if space was found to curve inwards, the universe could end in a final crunch; an event Schmidt calls the "gnaB giB", which is Big Bang backwards and an example of the little jokes astronomers like to tell.