Download Astronomy Quiz #1 Answers

Name:_________________________
SNC1D – Astronomy Quiz #1 Answers
1. Match up the definitions on the right with the correct term on the left. Write the letter of the
term in the space beside the definition.
(5 – KU)
__E____ contains hundreds of thousands
of stars, drawn together by the stars’
gravity.
___C___ a system with two stars
___A___ material in the universe that is
invisible
___B___ energy that travels in waves
___D___ leftovers from the formation of
the universe
A – dark matter
B – electromagnetic radiation
C – binary system
D – cosmic background radiation
E – globular cluster
2. Fill in the blanks with the correct vocabulary word.
(5 – KU)
_black hole (various answers)_
__________nebula______________
__________celestial objects_____
__________nuclear fusion______
all galaxies have this
a large cloud of dust and gas
objects we can see in the sky
the process in which the nuclei of atoms fuse together and
form larger atoms
__________supernova___________ when a star explodes
3. Explain what astronomers mean when they say light from a distant galaxy is “redshifted”. Draw a diagram to illustrate your answer.
(4 – COM)
-spectral lines are shifted to the red end of the visible spectrum
-this means that the wave lengths facing us/toward us are longer (like colour red),
showing stars are moving away from us/each other
-diagram should be of 2 visible spectra with lines; first one is the original, second one
should show that they shifted towards the red end of the spectrum
a. What does a large red shift indicate about a galaxy’s motion?
-it indicates that the galaxy’s expanding
(1 – KU)
4. Describe our galaxy. What is it called? What type of galaxy is it? How long (diameter)
and how thick (at its widest point) is our galaxy?
(4 – KU)
-Milky Way
-barred spiral
-100,000 ly (diameter)
-2,000 (thickness)
5. The distance from the Milky Way to the furthest galaxies is 13 000 000 000 ly.
Convert this measurement to scientific notation.
(1 – KU)
10
-1.3 X 10
Name:_________________________
6. Convert 3.21 x 10 to standard notation.
-3,210,000,000
(1 – KU)
7. What are the two important discoveries made by Edwin Hubble?
-many galaxies existed beyond the Milky Way
-almost all galaxies are moving away from each other
(2 – KU)
9
8. Some galaxies are thought to produce many more new stars than others. What
characteristics do galaxies with a high rate of production of stars have in common?
(2 – MC)
-they have large amounts of dust and gas
9. Explain why looking at a star in the night sky is like looking back in time. (2 – COM)
-the light we see was emitted, then travelled some distance to get to us. It takes time
to get the light to Earth, so we are seeing light that has been produced in the past
10.Explain the difference between an astronomical unit and a light-year. When do we use
each measurement? Which one is longer, 1 AU or 1 ly?
(4 – COM)
-AU: the average distance between the Sun and the Earth, approx 150,000,000km
-ly: the distance light travels in one year, approx 9,000 billion km
-AU: measures distances in the solar system
-ly: measures distances outside the solar system
-ly is longer than AU  1 ly = 63,000 AU
11.When galaxies do collide, why is it that so few of their stars collide as well? (2 – MC)
-everything is so far apart that it’s very unlikely for stars to be in the same place in
their respective galaxies to collide
12.Describe the Big Bang Theory, and provide one source of supporting evidence for the
theory.
(2 – MC)
-BBT: universe formed when an infinitely small and dense point suddenly and rapidly
expanded in a single moment
-cosmic background radiation: what is thought to be the leftover energy from the
universe’s creation, present everywhere and consistent with the BBT