1. A parsec equals _________ light years
a. 2
b. 3.26
c. 5.1
d. 10.33
2. How close is the nearest star system to the Sun?
a. 4.2 light years
b. 6.7 light years
c. 9.8 light years
d. 12.12 light years
3. A billion minutes equals ___________ years
a. 890
b. 1129
c. 1314
d. 1902
4. How many galaxies are contained within the "Local Group?"
a. 12
b. 33
c. 54
d. 129
5. The observable Universe consists approximately of how many super clusters?
a. 100
b. 10,000
c. 100,000
d. 10,000,000
6. What is the main difference between a refractor telescope and a reflector telescope?
a. one can see infrared radiation through a refractor, but not through a reflector
b. a refractor uses lenses; a reflector uses mirrors
c. a refractor only allows observers to see planets; a reflector only allows observers to see stars
d. there is no difference between them
7. A telescope's light gathering capability is determined by its __________
a. aperture
b. focal point
c. eyepiece magnification
d. none of the above
8. Why can reflector telescopes be so much larger than refractor telescopes?
a. because lenses are so much more expensive than mirrors
b. because mirrors can be supported from behind and so can be much larger than lenses which cannot be supported on the front or back
c. because reflector telescopes
d. they aren't. Refractor telescopes can be much larger than reflectors.
9. Who invented the reflector telescope?
a. Hans Lippershey
b. Galileo Galilei
c. Isaac Newton
d. Tycho Brahe
10. Which of the following are the advantages of reflectors over refractors? (Could be more than one)
a. refractors have problems with chromatic aberration. Reflectors don't.
b. reflectors can be larger
c. lenses have to be shaped perfectly on both sides. Mirrors have to be perfectly shaped only on one side.
d. none of the above
11. What is the advantage of an orbiting telescope over a ground based telescope? (could be more than one)
a. an orbiting telescope is above most of the atmosphere and so the images are not obscured by the gases
b. the angular resolution in orbiting telescope images is limited only by diffraction
c. more electromagnetic radiation can reach the orbiting telescope than a ground based telescope
d. all of the above
12. How much of the atmosphere is located below the altitude of 100 kilometers above Earth's surface?
a. half of it
b. 75%
c. 89%
d. 99.99%
13. The eight orbiting telescopes NASA launched 1962-1975 were designed to study the __________
a. Sun
b. moon
c. Earth
d. distant galaxies
14. Why wasn't the Hubble Telescope launched in October 1986 as originally planned?
a. the objective mirror was ground too fine
b. the Space Shuttle program suspended operations earlier that year due to the Challenger explosion
c. the gyroscopes were discovered to have been faulty
d. It wasn't delayed. The Hubble Space Telescope was launched in October 1986
15. Which Space Telescope, launched last year, is Hubble's successor?
a. James Webb Telescope
b. Johannes Kepler Telescope
c. Vesto Slipher Telescope
d. Harlow Shapley Telescope
16. If a star's parallax angle is 0.5 arc-seconds, what is its distance?
a. 1 parsec
b. 2 parsecs
c. 3 parsecs
d. 5 parsecs
17. ______ was the first star whose parallax angle was accurately measured.
a. 61 Cygni
b. Sirius
c. Alpha Centauri
d. Ross 248
18. Which star exhibits the highest proper motion?
a. Barnard's Star
b. Alpha Centauri
c. Sirius
d. Procyon
19. Wolf 359, Ross 154 and Lalande 21185 are stars named for___________
a. the name of the astronomers who cataloged those stars
b. the name of the observatories at which those stars were first observed
c. the quadrant of the galaxy in which the stars are located
d. none of the above.
20. How were astronomers able to identify the closest stars before they knew the distances to any of them?
a. the closest stars were the brightest stars
b. the closest stars exhibited the highest proper motion
c. the closest stars were circumpolar
d. the closest stars were closest to the horizon
ANSWERS
1. 1. A parsec equals _________ light years
b. 3.26
A parsec, or "parallax second" is equal to the distance at which a disc whose diameter equals Earth's orbital radius would subtend an angle of one arc-second. It equals about 3.26 light years.
2. How close is the nearest star system to the Sun?
a. 4.2 light years
The nearest star system, Alpha Centauri, consists of three stars. Proxima Centauri, the closest of these three stars to the Sun, is about 4.2 light years away. The other two stars, Alpha Centauri A and B are far more distant, but still part of the same system.
3. A billion minutes equals ___________ years
d. 1902
Explaining that a billion minutes equals 1,902 years is just another way of trying to convey the enormousness of the number 1,000,000,000. Another way: one billion seconds equals 32 years.
4. How many galaxies are contained within the "Local Group?"
c. 54
The largest three Local Group Galaxies are the Andromeda Galaxy, the Milky Way and the Triangulum Galaxy. This galaxy group is a very small part of the Local Supercluster.
5. The observable Universe consists approximately of how many galactic super clusters?
d. 10,000,000
Yet another unfathomable fact! Hundreds of billions of galaxies spread out over more than 10 million galactic super clusters
6. What is the main difference between a refractor telescope and a reflector telescope?
b. a refractor uses lenses; a reflector uses mirrors
Hence the name reflector. Reflectors are considered by many to have been an improvement over the refractors.
7. A telescope's light gathering capability is determined by its __________
a. aperture
The aperture equals the diameter of the objective lens or, in the case of a reflector, the primary mirror. A circle's area is proportional to the square of the radius which is one half the diameter. The greater the diameter the larger the area of the light collecting surface.
8. Why can reflector telescopes be so much larger than refractor telescopes?
b. because mirrors can be supported from behind and so can be much larger than lenses which cannot be supported on the front or back
9. Who invented the reflector telescope?
c. Isaac Newton
Newton invented this mirror based telescope in 1680 in order to avoid the chromatic aberration that plagued refractor telescopes.
10. Which of the following are the advantages of reflectors over refractors? (Could be more than one)
a. refractors have problems with chromatic aberration. Reflectors don't.
b. reflectors can be larger
c. lenses have to be shaped perfectly on both sides. Mirrors have to be perfectly shaped only on one side.
11. What is the advantage of an orbiting telescope over a ground based telescope? (could be more than one)
d. all of the above
12. How much of the atmosphere is located below the altitude of 100 kilometers above Earth's surface?
d. 99.99%
13. The eight orbiting telescopes NASA launched 1962-1975 were designed to study the __________
a. Sun
They also observed flares on other stars and other objects in the galaxy. However, the objective of these orbiting telescopes was to study the Sun.
14. Why wasn't the Hubble Telescope launched in October 1986 as originally planned?
b. the Space Shuttle program suspended operations earlier that year due to the Challenger explosion.
15. Which Space Telescope, launched last year, is Hubble's successor?
a. James Webb Telescope
16. If a star's parallax angle is 0.5 arc-seconds, what is its distance?
b. 2 parsecs
A star's distance measured in parsecs equals 1 divided by the parallax angle expressed in arc-seconds
17. ______ was the first star whose parallax angle was accurately measured.
a. 61 Cygni
Friedrich Wilhelm Bessel first measured the parallax of the star 61 Cygni in 1838.
18. Which star exhibits the highest proper motion?
a. Barnard's Star
About 10.5" per year: a steady clip for a star!
19. Wolf 359, Ross 154 and Lalande 21185 are stars named for___________
a. the name of the astronomers who cataloged those stars
20. How were astronomers able to identify the closest stars before they knew the distances to any of them?
b. the closest stars exhibited the highest proper motion
Instead, astronomers correctly assumed that the closest stars would exhibit the highest proper motions! All stars move very rapidly. However, those closest to us would tend to appear to move more quickly through the sky than more distant stars. As an analogy, imagine you're watching a car speed down the freeway. If you're standing close to the freeway, the car will appear to move very quickly. If you're far away from the freeway, the car will seem to move more slowly across your viewfield.
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