Podcaster: Richard Drumm
Title: Space Scoop: Black Holes: Devils in Disguise
Organization:365 Days Of Astronomy
Link : astrosphere.org ; http://unawe.org/kids/unawe1621/
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: Black Holes: Devils in Disguise
It was Halloween a few weeks ago, and the streets were filled with all kinds of frightful characters, from ghastly ghouls to bloodsucking vampires.
But we all know these are just our friends and neighbors dressed in costumes and fake blood. Monsters don’t really exist … or do they?
While they’re not hiding in your closet or under your bed, in a way, monsters do exist out in space.
Black holes are the boogeymen of the Universe. They lurk in the dark, waiting for unsuspecting gas, planets and stars to stray too close. And when they do, they become the black hole’s dinner!
This sounds pretty wicked, so you might be surprised to learn that we’re talking about black holes this week because many have been spotted wearing shining halos!
Actually, halos are very common in space. Every galaxy is surrounded by a so-called halo made of old stars and a mysterious, invisible material called dark matter. The interesting thing about these newly discovered halos is that they are glowing.
Astronomers spotted them while studying a special type of galaxy called a quasar. Quasars are galaxies with feeding supermassive black holes in their centers.
As black holes feast, huge jets of energy spew out! To find out how, read “Space Can Be A Blast”, the UNAWE entry for November 28, 2012.
These powerful jets shoot out from the black holes and make the invisible halo glow. When this happens, our telescopes can see the gas as a glowing halo around the galaxy.
Now, these halos aren’t the ring-shaped halos you see in cartoons floating over the heads of angels, but are an irregularly shaped nebula surrounding the galaxy.
In the past, we’ve found that 1 in every 10 quasars has a halo. But now, a team of Swiss, French and other European ESO astronomers have looked at some quasars using MUSE, the Multi Unit Spectroscopic Explorer. This is a powerful new imaging spectroscope on telescope #4 of the VLT telescopes at the Paranal Observatory in Chile.
The ESO astronomers found that all of the 19 bright quasars they looked at had halos! They weren’t even looking for halos in the first place!
The astronomers’ original goal was to study the large scale structure of the Universe where quasars are the bright spots or nodes on stupendously long filaments of hydrogen & helium gas and dark matter.
So, the next question we need to answer is: do all quasars have halos or were we just looking at an especially, uh, angelic bunch? Time will tell, but it sure looks like it’s all quasars. We’ll see. You can bet that the ESO astronomers will be looking at lots of quasars as the next few years go by.
Stay with us here for more on this evolving story!
Hey, Here’s a Cool Fact:
These halos extend up to 300,000 light-years away from the centers of the quasars. That’s three times longer than our galaxy is wide!
But that’s not the cool thing. This is:
The light that was emitted by the glowing gas is called Lyman Alpha light and is actually in the ultraviolet part of the spectrum that our eyes and the MUSE instrument cannot see.
Ordinarily Lyman Alpha observations have to be done by telescopes in space because that color of UV light gets absorbed by our atmosphere.
However, because the astronomers were looking at quasars, and these galaxies are really, really far away, the expansion of the Universe has redshifted the UV light down into the blue end of the spectrum.
And unlike UV, blue light can be detected from the ground by the MUSE instrument’s detectors.
Slick, eh?
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!