Observing Matter & Space
What problem is solved by sending telescopes into space?
interference of Earth’s atmosphere in detecting electromagnetic radiation
Scientists determine the composition and temperature of stars _____.
by analyzing the spectra of the light that stars emit
What type of galaxy is the Milky Way?
Spiral
During the first few minutes after the Big Bang, the universe was opaque. Light could not go through it. Why?
The mix of particles was so dense that photons could not get through.
The apparent magnitude of a star changes with the _________ .
Distance
If a dense, non-light producing, interstellar gas were to move between a star and Earth, what would happen to the spectra of the light from the star as measured on Earth?
The number of absorption lines would likely decrease.
What is the small, hot, extremely dense core left after a star collapses called?
white dwarf
What is an irregular galaxy?
a galaxy with no particular shape
What characteristic of the Cosmic Microwave Background Radiation (CMBR) provides evidence that the universe is expanding?
The CMBR can be detected coming from all directions.
The _________ magnitude is the measure of how bright each star would be if it were at the same distance (10 parsecs) from an observer.
Absolute
How will the spectra lines recorded on Earth be shifted for a light-emitting object that is moving neither toward nor away from Earth?
They will not be shifted at all.
What would an older star be most likely composed of?
is composed mostly of hydrogen
What measurement would be best used to measure the distance to the edge of the observable universe?
gigalight-year (or one billion light-years)
If the spectral lines from a star are shifted toward the red end of the spectrum, what must be true about how the star is moving?
the star is moving away from Earth
During the main-sequence stage, how is energy generated in a star’s core?
Hydrogen fuses into helium.
Where is our sun's energy produced?
in the core
Relates a star with a large mass to its expected life cycle.
Stars with a greater mass conduct fusion at a faster rate, which leads to a shorter lifespan as a main-sequence star.
An observer indicated a well-shaped structure with many closely spaced stars. Spectra indicate dominantly older stars. What is he likely looking at?
A star cluster
What is the apparent magnitude of a star a measure of?
The brightness of the star as seen from Earth
How long would a star with the sun’s mass stay on the main sequence?
as long as it fuses hydrogen
How does solar wind effect Earth's magnetic field?
It shifts the field in a direction away from the sun.
What is a large, bright star whose hot core has used most of its hydrogen?
Giant
How could an observer tell which way a spiral galaxy is turning even though they can't see it move?
By looking at the direction the spiral arms are going.
During a star's main-sequence stage, how is energy generated in the star's core?
Hydrogen fuses into helium
What can parallax be used to determine about stars?
The distance to a star