Name_______________________________ AST 110 - Questionnaire for How the Universe
ID: 293256 • Letter: N
Question
Name_______________________________
AST 110 - Questionnaire for How the Universe Works - "Inside the Milky Way"
https://www.youtube.com/watch?v=ttz4Sr0tZFg
1. One could consider the Milky Way a _______ of stars.
2. There are basically two types of galaxies, _____________ and spiral galaxies.
3. Messier 74 (M74) is a beautiful spiral galaxy that is only _____ million light years from Earth (for
comparison, our big sister galaxy, Andromeda (M31) is 2 million light years away).
4. The Milky Way has two main spiral arms, Scutum Centaurus, and the ____________ arm. Our galaxy
measures a staggering 600 thousand ____________ miles or about 100,000 light years in size, hence it
takes light 100,000 years to cross our galaxy.
5. The Orion nebular is "just around the corner" from the Sun, about _____ hundred light years away.
6. The Milky Way is filled with ___________ of stars in every direction.
7. The bright glowing clouds in galaxies are called nebulas. The color of the nebulas reveals what the
nebulas are made of. If there is a green glow from a nebula, this tells us that it contains ____________.
8. X-ray emissions from the Orion nebula reveal that the nebula contains some of the _________ stars
in our galaxy.
9. Stars form in a region of cold gas under a tug-of-war between gravity and gas __________. Gravity
wins and the gas crunches down, getting denser, until it ignites as a star at a temperature of "18 million"
degrees (that's degrees Fahrenheit, not Celsius or Kelvins, which is equivalent to 10 million degrees).
10. The Crab Nebula exploded about ________ years ago, the recent past. Chinese manuscripts
described the sudden arrival of a brilliant new star that was even visible during the ______.
11. Supernovae happen about once every ____ years in a galaxy on average. The last supernova
observed in our galaxy that anybody saw was about _______ years ago. To get around this
problem, astronomers watch thousands of galaxies, increasing the probability of detection.
12. When it starts to make iron, a giant star is ___________ ("the battle is lost").
13. Supernovas are the industrial ________ of our galaxy. "We are all linked to the Cosmos."
14. ________ stars don't die in a cataclysmic explosion. When the Sun becomes a red giant in about 4
or 5 billion years, the outer layers will be held so loosely, they will be blown away gently in a cosmic
________.
15. The Earth goes "downtown" to the heart of the Milky Way where the density of stars is tremendous,
about a _________ times higher than out here by the Sun.
16. The black hole at the center of the Milky Way has a mass of about ____ million solar masses.
17. The Milky Way is one of the oldest objects in the cosmos, at least ____ billion years old.
18. Globular clusters aren’t the only groups of stars orbiting the Milky Way, there are also Ultra- ______
Dwarf galaxies, containing just a few __________ or a thousand stars.
19. Our galaxy is much bigger than it appears. Anything that has mass has a gravitational pull. The
more the mass, the stronger the pull. Stars near the edge of the Milky Way's disk are moving at
almost the same speed as those much closer in, which shouldn't be the case, unless there is a lot
more mass in the Milky Way than what we can see. This mass is referred to as ________
___________, and it is the glue that holds galaxies together.
20. Telescopes are ______ machines. Because light travels at a finite speed, when we look at distant
objects, we see them as they were in the distant past.
21. When we look back far enough in time and space, all the galaxies disappear. We are looking at a
time before stars formed known as the "_______ Ages".
22. Look back 380,000 years after the Big Bang, and the Universe isn’t filled with darkness, but with
light that shows minute __________ or fluctuations in its structure. These indicate the early
concentration of matter in the Universe that led to the growth of the first galaxies, which also
required dark matter to accelerate the process. This is proven with the "Bolshoi" supercomputer
simulations that include both normal matter and dark matter.
21. The first stars in our Universe are ____ hundred times the mass of the Sun and a million times
as bright.
22. The Hubble Ultra Deep Field survey was obtained by the Hubble telescope covering a region of sky
equivalent to the width of a dime held 75 feet away from your eye. The galaxies that are seen in
this image are young galaxies in the early Universe. They don’t resemble the star cities we see
today. They're lumpy, they're irregular, they appear to be interacting with their neighbors, and
they're physically very very _________.
22. Galaxies grew and are still growing due to collisions with other galaxies. If we could travel ____
billion years into the future, we would see the beginning of the great collision that will occur
between the Milky Way and the Andromeda galaxy.
23. Our galaxy belongs to a structure called "The Local Group" that contains about ____ galaxies.
24. The collision between the Milky Way and Andromeda galaxy will leave behind an _____________
shaped galaxy.
25. As is assumed with solar systems, galaxies likely have a ____________ zone, a region where the
conditions for life bearing planets is most likely. The cores of galaxies are unlikely places to find
planets with life because of the high density of stars and dangerous radiation.
Explanation / Answer
1. We can say Milky way galaxy as Collection of stars.
2. There are basically two types of galaxies Elliptical galaxies and spiral galaxies.
3. It is 32 million light years from the Earth.
4. The other one is Perseus arm.
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