Podcaster: Richard Drumm
Title: Space Scoop: When You Wish Upon A Star…
Organization: Astrosphere New Media
Link : astrosphere.org ; http://unawe.org/kids/unawe1447/
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…
When You Wish Upon A Star…
The darker the observing site, the brighter the night sky.
This episode’s album artwork features an amazing picture that was taken by a telescope in one of the most remote regions on Earth, the Atacama Desert, far from any towns or cities.
It shows the bright stars of the Wishing Well Cluster, which earned its name because of the many stars that resemble silver and gold coins sparkling at the bottom of a wishing well.
This very bright star cluster is easily seen with the naked eye if you happen to be in the southern hemisphere. It was discovered by French astronomer Nicolas Louis de Lacaille while observing from South Africa in 1752 and was catalogued three years later in 1755. It is one of the most spectacular open clusters in the whole sky.
In star clusters like this one, all the stars are born around the same time, from the same cloud of gas. All the stars in this cluster, for example, are around 300 million years old.
The Wishing Well Cluster, also known to astronomers as NGC 3532, and located in the Southern constellation of Carina, has a rich mix of around 400 red and blue stars. The color of these stars tells us about how massive they are.
More massive stars burn hotter and brighter and use up their fuel much quicker than their smaller siblings. Their cores have greater gravitational pressure due to their extra size, and the fusion reactions there run faster. Because of this we can tell that the redder stars in this picture are the more massive ones.
You see, they’re all now in the last phase of their evolution — the red giant phase. The bluer, less massive stars are still in an earlier phase of their lives. Being less massive, it could take them a few billion years to become red giants.
And to top it all off, they won’t be going supernova at the end, but will become the most beautiful objects in the night sky: planetary nebulae. Their cores will be left behind as white dwarf stars, burning verrrry hot, 4 times hotter than our Sun and emitting lots of ultraviolet light.
This is the so-called “black light” that geologists use for fluorescence demonstrations. The ultra-violet light will pour out of the white dwarf stars and hit the gas that was given off during the earlier red giant phase of the star. It’s the outer parts of the red giant star that were pushed out of the star’s gravity well and the UV light will make it fluoresce in pretty colors.
The most massive stars in the cluster aren’t visible in this picture. That’s because they have already raced through their short lives, used up their fuel and exploded as powerful supernovae long ago.
In doing so they have created all the natural elements of the periodic table of the elements and blown them like so much cosmic phlegm into the cosmos! Ewww… But some of that phlegm is gold, so it’s not all gross…
Hey Here’s a Cool Fact
In our Galaxy, you can tell how old a star cluster is based on where it’s found. Older clusters are normally found farther from the center of the galaxy than younger clusters. So it’s like the outskirts of the galaxy are the retirement homes for star clusters…
Thank you for listening to 365 Days of Astronomy!
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. In the new year the 365 Days of Astronomy project will be something different than before….Until then…goodbye