Idaho Skies Transcript for January 9th and 10th

RACHEL
Welcome to Idaho Skies for January 9th and 10th. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
All the matter in the universe began expanding at its birth, some 13.7 billion years ago.

PAUL
The expansion of space is carrying matter, like the galaxies with it. That means that while the galaxies are moving apart from one another, they don’t experience a sense of movement relative to space around them. However, the gravity exerted by the matter in galaxies can make them move independently of the expansion of the space between them.

RACHEL
Cosmologists have wondered if the gravitational force exerted by galaxies could pull them together faster than expanding space-time could carry them apart. Perhaps there’s enough matter in the universe to stop the relative motion between all the galaxies, even through space would continue to expand. Or maybe there’s enough matter to bring all the galaxies together in a great crunch some time in the distant future.

PAUL
To answer this question, astronomers began measuring the distance and speed of galaxies. They needed a tool bright enough to work across the universe and that tool was supernovae explosions. On January 9th, 1998, two teams of astronomers announced that very distant galaxies were farther apart than they expected. This is exactly the opposite behavior that cosmologists thought they would find.       

RACHEL
It appears that space has developed an anti-gravity property. Five billion years ago, space began pushing galaxies apart even faster. The force responsible for this behavior is still unknown, but not unpredicted. Einstein introduced a cosmological constant to into his math to keep the universe static, or free of expansion and collapse. Today we call it Dark Energy and for some reason, it began accelerating the expansion of the universe five billion years ago.

PAUL
That’s Idaho Skies for the 9th and 10th of January.

RACHEL
Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com.

For Idaho Skies this is Rachel…

PAUL
…and Paul.

RACHEL
Dark skies and bright stars.