Podcaster: Richard Drumm
Title: Space Scoop: Star Factories Were More Productive In The Past
Organization: 365 Days Of Astronomy
Link : astrosphere.org ; http://unawe.org/kids/unawe1602/
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 365 Days of Astronomy. 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.
Today’s story is:
Star Factories Were More Productive In The Past
There’s no such thing as a stupid question. Some of the simplest questions have the most interesting answers. For example: why is space black?
To answer this question, we have to look at the distances between stars, the speed that light travels and how the Universe is growing bigger all the time.
This is called Olbers’ Paradox. It argues that the Universe can’t be static and infinitely old. If it was then there would be a star in every possible direction you looked, day or night. Somewhere along every possible line of sight there would be a galaxy and a star which would send light toward you from that direction.
Thus the entire night sky would be lit up like the Sun. Since the night is dark, then the Big Bang likely happened because then the Universe isn’t static and it isn’t infinitely large and there hasn’t been enough time passing for the light to travel to us.
Astronomers using the ALMA radio telescope array in Chile have been trying to answer another simple question, one that they ask themselves: Why are more stars being born in some galaxies than others?
Now at a first glance the answer seems obvious – bigger galaxies have more cosmic gas, so more stars will be born in them than in small ones. After all, cosmic gas is the main ingredient needed to make stars.
While this is true most of the time, it’s not a concrete rule.
Scientists using ALMA have just discovered that even with the same amount of star-making gas, galaxies in the distant past churned out a much higher number of stars than they do nowadays.
Billions of years ago, apparently galaxies were simply more productive, better at turning gas into stars. The galaxy in which we live, the Milky Way, normally makes one new star per year. In the past, some galaxies could create a few hundred stars every year!
Galaxies that crank out new stars in a big way are the so-called “Starburst” galaxies. Today’ album artwork features one such galaxy, NGC 1313, which can be seen in the small southern constellation Reticulum, “The Net” which is named after the crosshairs in a telescope’s finder eyepiece.
Astronomers still don’t know why these early galaxies were more productive, but they suspect it’s related to cosmic collisions.
Galaxies were much more likely to crash into one another in the past, when there was less space and galaxies were bigger. This might have had the side effect of more stars being born.
Hey, Here’s A Cool Fact:
The seven starburst galaxies that were studied were over 9 billion light years away from Earth. So we are seeing them as they were just 4 billion years after the Big Bang.
The astronomers used infrared observations from NASA’s Spitzer Space Telescope and the ESA’s Herschel Space Observatory to measure the star formation rate.
They used ALMA and a submillimeter radio telescope called IRAM in the French Alps to measure the amount of carbon monoxide or CO in the seven galaxies.
This CO measurement serves as an indicator of the total amount of gas the galaxies have to form stars from.
So there are no stupid questions. I just hope I didn’t come up with a stupid answer!
Thank you for listening to 365 Days of Astronomy!
End of podcast:
365 Days of Astronomy
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