Electromagnetic Spectrum
Which type of electromagnetic wave has the longest wavelength?
Radio waves
Approximately how old is the universe?
About 13.7 billion years
A galaxy is moving away from Earth. Is its light redshifted or blueshifted?
Redshifted
What gas makes up most of a star?
Hydrogen
What is the large cloud of gas and dust where stars begin?
A nebula
Which part of the electromagnetic spectrum can human eyes detect?
Visible light
Approximately how old is Earth?
About 4.6 billion years
A star is moving toward Earth. Is its light redshifted or blueshifted?
Blueshifted
What process powers stars by turning hydrogen into helium?
Nuclear fusion
What is the stage after a nebula, when gravity pulls material together and it heats up?
Protostar
List the electromagnetic spectrum in order from longest to shortest wavelength.
Radio, microwave, infrared, visible, ultraviolet, X-ray, gamma ray
Describe the universe at its beginning.
It began in a very hot, dense state (described as a singularity).
What happens to observed wavelengths during redshift?
They are stretched, becoming longer.
Name THREE of the five characteristics of stars
Any three: brightness, color, surface temperature, size, mass
What is the stage in which a star spends most of its life shining through fusion?
Main sequence
As wavelength decreases, what happens to frequency and energy?
As wavelength decreases, what happens to frequency and energy?
Name TWO pieces of evidence supporting the Big Bang Theory.
Cosmic background radiation and redshift of distant galaxies
What happens to observed wavelengths during blueshift?
They are compressed, becoming shorter.
What two star properties are compared on an H-R diagram?
Temperature and brightness
After the main sequence, what stage does a low- or medium-mass star enter?
Red giant
Which has more energy: an X-ray or an infrared wave? Explain using wavelength.
An X-ray; it has a shorter wavelength and higher energy.
What two elements are listed as the most common in the universe?
Hydrogen and helium
Why does redshift from distant galaxies support the idea of an expanding universe?
It shows that distant galaxies are moving away from us.
What two opposing forces help keep a star stable?
Gravity pulls inward; energy from fusion pushes outward.
What explosive event can happen after a massive star becomes a red supergiant?
Supernova