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