Chapter 30 Questions Flashcards
What type of Galaxy is the Milky Way?
A spiral galaxy
What does the energy emitted by a quasar suggest?
The presence of a giant black hole.
What color are the hottest stars?
Blue
What makes up most of the universe?
Dark energy
What is important about Hubble’s discovery that there is a red sift in the spectra of galaxies?
Hubble found that the most distant galaxies showed the greatest red shift and thus were moving away from Earth the fastest.
How do stars with a negative number for their apparent magnitudes compare to stars with a positive number for their apparent magnitudes?
The lower the number of the star ‘s apparent magnitude, the brighter the star appears to observers on Earth.
What can parallax be used to calculate?
a star’s distance within 1,000 light-years of Earth
What color are the coolest stars?
Red
How do scientists determine the composition and temperature of stars?
Scientists have learned that stars are made up of the same elements that compose Earth.The surface temperature of a star is indicated by its color.
How is energy generated in a main sequence star?
energy continues to be generated in the core of the star as hydrogen fuses into helium.
How long would a star with the sun’s mass stay on the main sequence?
About 10 billion years
What happens at 10,000,000 °C in a protostar?
At this temperature, nuclear fusion begins.
What did Hubble discover in the 1920s?
Hubble found that the spectra of galaxies, except for the few closest to Earth, were shifted toward the red end of the spectrum.
When did the Big Bang occur?
About 14 billion years ago.
How long will a star with a mass the same as our sun stay on the main sequence?
about 10 billion years.
What is absolute zero?
about -273°C or 0 Kelvin.
Two stars are same size and distance from Earth but one has a higher apparent magnitude than the other. Explain why.
Because the star is not as bright as the other. The lower the number of the star ‘s apparent magnitude, the brighter the star appears to observers on Earth.
How is apparent magnitude different from absolute magnitude?
apparent magnitude the brightness of a star as seen from the Earth and absolute magnitude the brightness that a star would have at distance of 32.6 light-years from Earth.
How far from Earth is the closest star other than our sun?
4 light years.
How far from Earth is the closest star other than our sun?
4 light years.
