Podcaster: Richard Drumm
Title: Space Scoop: Is the Universe Speeding Away From Us?
Organization:365 Days Of Astronomy
Link : astrosphere.org ; http://unawe.org/kids/unawe1702/
Description: Space scoop, news for children
Bio: Richard Drumm is President of the Charlottesville Astronomical Society and President of 3D – Drumm Digital Design, a video production company with clients such as Kodak, Xerox and GlaxoSmithKline Pharmaceuticals. He was an observer with the UVa Parallax Program at McCormick Observatory in 1981 & 1982. He has found that his greatest passion in life is public outreach astronomy and he pursues it at every opportunity.
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Transcript:
This is the 365 Days of Astronomy Podcast. Today we bring you a new episode in our Space Scoop series. This show is produced in collaboration with Universe Awareness, a program that strives to inspire every child with our wonderful cosmos.
Is the Universe Speeding Away From Us?
Most scientists believe that about 13.82 billion years ago the Universe exploded into existence in what we call the Big Bang. Since then, it has evolved into the place we see today — and it’s still growing!
No matter which direction we look in space, distant galaxies appear to be moving away from us. The farther away a galaxy is, the faster it’s moving away. This is called the ‘expansion of the Universe’.
The expansion of the Universe can be measured in a number of ways. One technique is to study the ‘afterglow’ of the birth of the Universe. Like smoke drifting away after fireworks, an afterglow from the Big Bang lingers in space.
COBE, the Cosmic Background Explorer mission, WMAP, the Wilkinson Microwave Anisotropy Probe and the Planck spacecraft have taken this approach.
Another method is to use a natural phenomenon called ‘cosmic lensing’. Cosmic lensing happens when two galaxies are lined-up, one behind the other, as we look at them in the sky. The light from the distant galaxy is bent around the nearer one, because of gravity.
Instead of the distant galaxy being hidden behind the nearer one, we see a ghost image or ‘lensed image’ of the galaxy. Sometimes we can see many lensed images of the same distant galaxy. You can see this effect if you do a Google Images search for ‘lensed galaxy’.
Depending on the shape and position of the lensed images, they show the distant galaxy when it was at different ages. By comparing different lensed images, we can work out how far away the distant galaxy lies. This is called the time-delay distance technique. And we can use this to determine how fast the Universe is expanding.
An international team of astronomers with the delightful acronym H0LiCOW used the Hubble Space Telescope to study 5 galaxies in order to arrive at an independent measurement of the Universe’s Hubble constant, it’s expansion rate. H0LiCOW stands for H0 Lenses in COSMOGRAIL’s Wellspring.
And COSMOGRAIL is the COSmological MOnitoring of GRAvItational Lenses.
So we have an acronym within an acronym! So meta!
This method is the most simple and direct way to measure the Hubble constant as it only uses geometry and General Relativity, no other assumptions need to be made.
The scientists have found that their new measurement of the expansion of the nearby Universe was in excellent agreement with other measurements.
But…
You just KNEW there was a “But” coming, didn’t you?
But the measurements of the expansion of the very distant Universe don’t agree with previous measurements. The new study says that the Universe is expanding even faster than expected!
So the expansion rate of the Universe is now starting to be measured in different ways with such high precision that these discrepancies may possibly point toward new physics beyond our current knowledge of the Universe.
So stay tuned to the 365 Days of Astronomy Podcast for the latest & greatest space news!
Hey, Here’s A Cool Fact:
The fact that all galaxies appear to be moving away from us doesn’t mean that we’re at the center of the Universe.
A simple way to think of it is to imagine baking a loaf of raisin bread. As the bread dough rises, all the raisins move farther apart from one another. No matter where in the loaf they are, every raisin sees all of the others moving away from it!
If the raisins had eyes, that is. Yeah.
Thank you for listening to the 365 Days of Astronomy Podcast!
End of podcast:
365 Days of Astronomy
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The 365 Days of Astronomy Podcast is produced by Astrosphere New Media. Audio post-production by Richard Drumm. Bandwidth donated by libsyn.com and wizzard media. You may reproduce and distribute this audio for non-commercial purposes. Please consider supporting the podcast with a few dollars (or Euros!). Visit us on the web at 365DaysOfAstronomy.org or email us at info@365DaysOfAstronomy.org. This year we will celebrate more discoveries and stories from the universe. Join us and share your story. Until tomorrow! Goodbye!