astronomy 123 module 5-8 Exam review
If our Sun were to become a black hole, the radius of its event horizon would be about
3 kilometers
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
When laser beams in an interferometer combine
an interference pattern of bright and dark light is formed
After travelling 140 million light years from the 170817 neutron star merger, gravitational waves and gamma rays
arrived at earth at almost exactly the same time
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
According to the General 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
After a star collapses to form a black hole, the only information we can measure is
its mass and spin
A gravitational lens is formed by
mass between the source and earth
Spacetime effects like time dilation are only noticeable when
objects move close to the speed of light
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
In the first direct detection of gravitational waves by LIGO in 2015, the waves came from
the merger of two black holes
The first time that astronomers observed both gravitational waves and electromagnetic waves from the same event, what they were observing was:
the merger of two neutron stars
Observations of the spectra of the afterglow of the binary neutron star merger revealed
the presence of newly created heavy elements
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
According to General Relativity, in a freely falling reference frame, light
travels in a straight line
In the 2015 gravitational wave discovery event, the two black holes
were each about 30 solar masses
