Exploring the Cosmos - Class Test 1 - Particles, Forces & the Big Bang
1. What is the observable universe?
The portion of the universe from which light had enough time to travel to us.
All parts of the universe that are not obscured by celestial objects.
The portion of the universe that our eyes can see.
Part of the universe that the most powerful telescopes can resolve.
2. One of Kepler’s laws states that
Rhere is no special centre around which the universe rotates.
Planets can not be more massive than the star around which they orbit.
Planetary orbits are elliptical.
A planet orbits the sun with constant angular velocity.
3. The apparent brightness of stars changes with their distance (r) away from us as
1/r^2
r
1/sqrt(r)
1/r
4. Edwin Hubble observed that galaxies seem to be moving away from us in all directions. This means:
We are close to the centre of the expanding universe.
The measurements are not accurate enough to pinpoint the centre of expansion.
We are at the centre of the expanding universe.
The universe is expanding, but it has no centre.
5. Who of the following believed that the Sun and all of the planets orbit around the Earth?
Ptolemy
Copernicus
Tycho Brahe
Galileo
6. A closed universe
has negative curvature, like a saddle.
is flat, like a plane.
will expand forever.
has positive curvature, like a sphere.
7. The sky is dark at night because
there is dark matter in between the stars.
the universe is only sparsely populated with stars.
some stars are so far away that their light has not yet reached us.
our eyes are not sensitive enough.
8. What is the observable universe?
The portion of the universe from which light had enough time to travel to us.
The portion of the universe that our eyes can see.
Part of the universe that the most powerful telescopes can resolve.
All parts of the universe that are not obscured by celestial objects.
9. Kepler’s laws show that
planetary orbits are elliptical.
there is no special centre around which the universe rotates.
a planet orbits the sun with constant angular velocity.
planets can not be more massive than the star around which they orbit.
10. The red shift of light from very distant galaxies shows they are
formed a long time ago compared to nearby galaxies.
very far away.
accelerating away from us.
moving toward us.
11. Edwin Hubble observed that galaxies seem to be moving away from us in all directions. This means:
we are at the centre of the expanding universe.
the measurements are not accurate enough to pinpoint the centre of expansion.
the universe is expanding, but it has no centre.
we are close to the centre of the expanding universe.
12. The assumption of universality states that
the physics of the universe is the same everywhere and at all times.
the university looks the same at all epochs.
the universe looks the same in all directions.
the universe looks the same in all locations.
13. What was the famous and remarkable achievement of Eratosthenes in 240 BC?
He realised that the Earth goes around the Sun.
He measured the distance from the Earth to the Sun to within a few percent.
He measured the size of the Earth to within a few percent.
He realised that the Earth’s axis tilts, causing the seasons.
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