ASTR 123 Modules 5 & 6
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
The object(s) created by the merger of two black holes is
a single black hole with mass slightly lower than the sum of the merging ones
The 170817 event demonstrated that neutron star mergers
all of the above
When laser beams in an interferometer combine
an interference pattern of bright and dark light is formed
General Relativity predicts that light passing near a massive object like the sun will
appear bent when observed from Earth
According to the general theory of relativity, the presence of mass
causes a curvature (or warping) of spacetime
Current measurements of the Hubble constant H0
disagree depending on the method used
What is a key reason that gravitational waves are so much harder to detect than electromagnetic waves?
gravitational waves are much weaker than electromagnetic waves, and therefore require very, very precise equipment to detect
To predict whether a star will ultimately become a black hole, what is the key property of the star we should look at?
mass
We now know that most heavy elements such as gold are produced in
neutron star mergers
Special relativity gives a "speed limit", meaning that
objects cannot move faster than the speed of light
Spacetime effects like time dilation are only noticeable when
objects move close to the speed of light
Merging black holes can be observed
only by their gravitational wave emission
When scientists say that "black holes have no hair", what do they mean?
that once a black hole forms, very little information can be extracted from it about the material that is now inside
When astronauts aboard the International Space Station (ISS) in space 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
The region around a black hole where everything is trapped, and nothing can get out to interact with the rest of the universe, is called
the event horizon
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 speed c
The speed that gravitational waves travel is
the speed of light
The main postulate of special relativity is that
the speed of light is an absolute constant
The location of the 170817 neutron star merger was first determined using
three gravitational wave detectors
In the 2015 gravitational wave discovery event, the two black holes
were each about 30 solar masses
