Exploring the Cosmos - Class Test 2 - Galaxies and Large Scale Structure
1. In the Universe
galaxies occur randomly in space.
galaxies tend to occur in super-clusters which occur randomly in space.
galaxies tend to occur in clusters which occur randomly in space.
galaxies tend to occur in super-clusters which, in turn, form even larger structures which stretch across much of the known universe.
2. The correct order of the distance ladder from close to far is
Spectroscopic parallax, Cepheid Variables, Supernovae 1a, Hubble’s Law.
Spectroscopic parallax, Supernovae 1a, Cepheid Variables, Hubble’s Law.
Spectroscopic parallax, Cepheid Variables, Hubble’s Law, Supernovae 1a.
Supernovae 1a, Hubble’s Law, Spectroscopic parallax, Cepheid Variables.
3. A type Sb galaxy is
a barred spiral galaxy with moderately tightly wound arms.
a spiral galaxy with moderately tightly wound arms.
a barred spiral galaxy with very open arms.
a disc shaped galaxy with little gas and almost no new star formation.
4. A Seyfert galaxy is
another name for a type SO galaxy.
a galaxy that has been distorted by a close encounter with another galaxy so that there is a high rate of formation of new stars.
a galaxy that does not have a black hole at its centre and is free to radiate large amounts of energy.
a galaxy that is emitting an unusually large amount of energy due to a black hole at its centre.
5. Cepheid variable stars are important for distance measurements because
they emit radio waves whose frequency allows the calculation of their distance.
from their pulsation rate of their brightness, we can deduce their rotational speed.
from their pulsation rate of their brightness, we can deduce their intrinsic average brightness.
their brightness pulsates in a well defined way that allows them to be identified and their average brightness is independent of their size.
6. An S0 galaxy is
a spiral galaxy with many arms.
a very elongated elliptical galaxy.
a galaxy with intense star formation due to a collision with another galaxy.
a galaxy with a nucleus and a disc but little dust and gas.
7. A possible explanation of the formation of a giant elliptical galaxy is
it has a giant black hole at its centre that attracts many stars.
a giant spiral galaxy used up the gas and dust in its disc so that the generation of new stars ceased and the arms slowly broke up.
a giant spiral galaxy evolved into an elliptical galaxy.
it was formed by the merger of two or more galaxies.
8. Which of the following is not a characteristic of rich galaxy clusters?
Collisions of galaxies are likely to happen.
The cluster at the centre is often formed by one or more giant elliptical galaxies.
High density of galaxies.
Contains a large fraction of spiral galaxies.
9. A super-massive black hole would be most likely found in our galaxy
in one of its arms.
in the nucleus.
at the centre of a globular cluster.
in one of the open clusters of stars.
10. Astronomers have been able to measure the speeds of stars near the centre of our galaxy using
modern optical telescopes.
infrared telescopes.
X-ray telescopes.
radio telescopes.
11. A bright red region observed round a bright star in our galaxy is usually
a dust cloud that is absorbing the blue part of the light from the very luminous star and allowing only the red light to pass.
coloured dust ejected by a nearby supernova.
a region in which hydrogen atoms in a gas cloud are being excited and ionised by the very luminous nearby star and are emitting the red light.
a dust cloud scattering the light of a red giant star.
12. Population II stars are
metal poor and typically found in the spiral arms of a galaxy.
metal rich and typically found in the spiral arms of a galaxy.
metal rich and typically found in the nucleus and halo of a galaxy.
metal poor and typically found in the nucleus and halo of a galaxy.
13. On average the density of gas in the interstellar medium (ISM) is
similar to that in the Earth's atmosphere.
in the region of 1 hydrogen atom per cubic centimetre.
similar to that at the surface of the Sun.
in the region of 1 hydrogen atom per cubic metre.
14. Which of the following comprise the oldest members of the Milky Way?
The Sun and other solar mass stars.
Globular clusters.
Red giant stars in spiral arms.
Type O stars.
15. What can cause a galactic fountain?
Multiple supernovae occurring together.
A supernova occurring in the halo.
Winds and jets from newly-formed protostars.
The combined effect of spiral density waves.
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