"I'll learn to be more deferentially polite to viruses from now on."
THE DAILY ASTRONOMER
Friday, September 23, 2016
Quiz IV: Black Holes!
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"CASTING LIGHT ON BLACK HOLES"
WMPG'S "Radio Astronomy" show focuses on
black holes. Bowdoin College astronomer
Dr, Thomas Baumgarte discusses his black hole
research.
Radio astronomy is a weekly program broadcast on WMPG
90.9 FM at 1:00 p.m. on Fridays. You can also hear the
Also, listen to the show's archives at
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Black holes!
One of the most interesting of all astronomical phenomena: a region of space-time where the gravity is so powerful that not even light can escape its clutches. Apart from the super massive black hole residing in the galactic nucleus, more than 100 million black holes are lurking within the galaxy, scattered over the enormous region encompassing the Milky Way.
Today, we offer a black hole quiz: finding out what you know about objects that remain largely unknown even to astronomers. So, even if you don't know what they don't know, you will end up knowing alot. Black holes distort space, time, and common sense, so that last sentence was actually sensible.
1. About how massive is the black hole in the center of our galaxy?
a. two times more massive than the Sun
b. 450,000 times more massive than the Sun
c. 4,3 million times more massive than the Sun
d. 100 billion times more massive than the Sun
2. Even though we say that nothing can escape a black hole, it does "evaporate" through the emission of what?
a. gamma rays
b. Hawking radiation
c. neutrinos
d. x-rays
3. When will the Sun become a black hole?
a. tomorrow
b. In about 6.5 billion years
c. In about 10.7 billion years
d. The Sun will never become a black hole.
4. Black holes are created when highly massive stars explode and crush their cores into very small volumes. How much would we have to reduce Earth's volume to turn it into a black hole?
a. Earth would have to be the size of the moon
b. Earth would have to be the size of Madagascar
c. Earth would have to be the size of a marble
d. Earth would have to be the size of an atom
5. What is the name of the region around a black hole beyond which not even light can escape?
a. the event horizon
b. the K-T boundary
c. the singularity
d, there is no specific name for this region.
6. Who coined the term "Black Hole?"
a. J Robert Oppenheimer
b. John Archibald Wheeler
c. Fred Hoyle
d. Albert Einstein
7. "Wormholes," a favorite of science fiction authors, are hypothesized connections between black holes that could convey a person from one universe to another or to a distant part of the universe. What is the technical name of these wormholes?
a. "Wormhole" is the technical name
b. Wheeler conduits
c. Einstein-Rosen bridges
d. Newtonian nexus
8. IF the Sun were to become a black hole, what would happen to Earth?
a. It would be sucked into the black hole immediately, but the presidential campaign would still continue
b. It would continue to orbit the black hole just as it orbits the Sun
c. Earth would approach the black hole, but would be ripped apart by the tidal forces before it reached the event horizon
d. Earth would actually be pushed far away from the black hole toward the orbit of Saturn.
9. About how far away from our solar system is the closest known black hole?
a. 23,000 light years (the super massive black hole in the galactic center)
b. 10,338 light years away
c. 3,000 light years away
d. 98 light years away
10. True or false: Black holes reside in the centers of most, if not all, galaxies.
ANSWERS
1. c. 4,3 million times more massive than the Sun
And this supermassive black hole is about 14 million miles across.
2. b. Hawking radiation
The emission of Hawking radiation causes a black hole to very slowly lose mass and evaporate. Of course, this process requires many billions of years.
3. d. The Sun will never become a black hole.
The Sun is not massive enough to become a black hole. It will, instead, eventually become a white dwarf surrounded by a planetary nebula.
4. c. Earth would have to be the size of a marble
All of Earth's mass concentrated into a sphere the size of a marble. This is quite dense!
5. a. the event horizon
6. b. John Archibald Wheeler
7. c. Einstein-Rosen bridges
After Albert Einstein and Nathaniel Rosen
8. b. It would continue to orbit the black hole just as it orbits the Sun
One might think all the planets would be swallowed like bubbles down a drain. In fact. Earth would continue to orbit the black hole.
9. c. 3,000 light years away V616 Monocerotis is the closest known black hole. Astronomers know it exists because it is part of a binary star system. There could very well be closer black holes we haven't yet discovered because they have no companions.
10. True