Astronomy 123 - Final Exam - University
of Oregon - Frey - Quiz 1a-8c Exam Q’s
and A’s
The main postulate of special relativity is that - -the speed of light is an
absolute constant
- Time dilation means that - -moving clocks run slow
- Spacetime effects like time dilation are only noticeable when - -objects
move close to the speed of light
- Special Relativity gives a "speed limit", meaning that - -objects cannot
move faster than the speed of light
- When astronauts aboard the International Space Station (ISS) in space and
let go of an orange, it just floats there. Why is that? - -The ISS is falling
around the Earth, and in free fall, things feel no weight
- IF you are in a freely falling elevator near the top of a tall building, as the
elevator falls, your weight would be: - -equal to zero - you would be
weightless
- The equivalence principle says - -the effects of gravity are equivalent to
the effects of acceleration
- General Relativity predicts that light passing near a massive object like the
sun will - -appear bent when observed from Earth
- To predict whether a star will ultimately become a black hole, what is the
key property of the star we should look at? - -Mass
- The region around the black hole where everything is trapped, and nothing
can get out to interact with the rest of the universe, is called - -the event
horizon
- According to the general relativity, the presence of mass - -causes a
curvature (or warping) of spacetime
- In the first direct detection of gravitational waves by LIGO in 2015, the
waves came from - -the merger of two black holes
- A student shines a flashlight out the window of a very fast rocket. If the
normal speed of light is c, then - -the light always travels at c
, - Once a black hole forms, the SIZE of its event horizon is determined only
by - -the mass inside the event horizon
- Einstein suggested that the regular change (advance) in the perihelion of
the planet Mercury could be explained by: - -a distortion in spacetime
caused by the gravity of the Sun
- A gravitational lens is formed by - -mass between the source and the earth
- When one member of a binary star system is a black hole, and
astronomers detect flickering x-rays coming from the system, where are
these x-rays usually coming from? - -From a disk of material around the
black hole (material that has been pulled from the companion star and is
falling toward the black hole)
- What is the key reason gravitational waves are so much harder to detect
than electromagnetic (EM) waves? - -Gravitational waves are much weaker
tham EM waves, and therefore require very, very precise equiptment to
detect
- The speed of gravitational waves travel is - -the speed of light
- The gravitational wave signal from merging black holes is called a "chirp"
because - -as the black holes get closer, the signal frequency and amplitude
increase
- Merging black holes can be observed - -only by their gravitational wave
emission
- When laser beams in an interferometer combine - -an interference pattern
of bright and dark light is formed
- In the 2015 gravitational wave discovery event, the two black holes - -
were each about 30 solar masses
- The first time that astronomers observed BOTH gravitational waves and
electromagnetic waves from the same event, what they are observing was: -
-the spiraling toward each other of two neutron stars
- We now know that most heavy elements such as gold are produced in - -
neutron star mergers
- After traveling 140 million years from the 170817 neutron star merger,
gravitational waves and gamma rays - -arrived at earth at almost exactly
the same time
of Oregon - Frey - Quiz 1a-8c Exam Q’s
and A’s
The main postulate of special relativity is that - -the speed of light is an
absolute constant
- Time dilation means that - -moving clocks run slow
- Spacetime effects like time dilation are only noticeable when - -objects
move close to the speed of light
- Special Relativity gives a "speed limit", meaning that - -objects cannot
move faster than the speed of light
- When astronauts aboard the International Space Station (ISS) in space and
let go of an orange, it just floats there. Why is that? - -The ISS is falling
around the Earth, and in free fall, things feel no weight
- IF you are in a freely falling elevator near the top of a tall building, as the
elevator falls, your weight would be: - -equal to zero - you would be
weightless
- The equivalence principle says - -the effects of gravity are equivalent to
the effects of acceleration
- General Relativity predicts that light passing near a massive object like the
sun will - -appear bent when observed from Earth
- To predict whether a star will ultimately become a black hole, what is the
key property of the star we should look at? - -Mass
- The region around the black hole where everything is trapped, and nothing
can get out to interact with the rest of the universe, is called - -the event
horizon
- According to the general relativity, the presence of mass - -causes a
curvature (or warping) of spacetime
- In the first direct detection of gravitational waves by LIGO in 2015, the
waves came from - -the merger of two black holes
- A student shines a flashlight out the window of a very fast rocket. If the
normal speed of light is c, then - -the light always travels at c
, - Once a black hole forms, the SIZE of its event horizon is determined only
by - -the mass inside the event horizon
- Einstein suggested that the regular change (advance) in the perihelion of
the planet Mercury could be explained by: - -a distortion in spacetime
caused by the gravity of the Sun
- A gravitational lens is formed by - -mass between the source and the earth
- When one member of a binary star system is a black hole, and
astronomers detect flickering x-rays coming from the system, where are
these x-rays usually coming from? - -From a disk of material around the
black hole (material that has been pulled from the companion star and is
falling toward the black hole)
- What is the key reason gravitational waves are so much harder to detect
than electromagnetic (EM) waves? - -Gravitational waves are much weaker
tham EM waves, and therefore require very, very precise equiptment to
detect
- The speed of gravitational waves travel is - -the speed of light
- The gravitational wave signal from merging black holes is called a "chirp"
because - -as the black holes get closer, the signal frequency and amplitude
increase
- Merging black holes can be observed - -only by their gravitational wave
emission
- When laser beams in an interferometer combine - -an interference pattern
of bright and dark light is formed
- In the 2015 gravitational wave discovery event, the two black holes - -
were each about 30 solar masses
- The first time that astronomers observed BOTH gravitational waves and
electromagnetic waves from the same event, what they are observing was: -
-the spiraling toward each other of two neutron stars
- We now know that most heavy elements such as gold are produced in - -
neutron star mergers
- After traveling 140 million years from the 170817 neutron star merger,
gravitational waves and gamma rays - -arrived at earth at almost exactly
the same time
