Sun & Stars
These two gases make up the vast majority of our Sun's mass.
What are Hydrogen and Helium?
The region along a diagonal band on the H-R diagram where stars spend about 90% of their active lives fusing hydrogen in their cores.
What is the Main Sequence?
The three primary shape classifications used to categorize galaxies.
What are Spiral, Elliptical, and Irregular?
The definition of a light-year.
What is the distance light travels in one year?
The most widely accepted scientific theory describing the early expansion and formation of the universe.
What is the Big Bang Theory?
This reaction at the Sun’s core fuses hydrogen nuclei into helium, releasing massive amounts of energy.
What is Nuclear Fusion?
On an H-R diagram, our Sun falls approximately in this general region.
What is the middle of the Main Sequence?
The name and shape classification of the galaxy containing our solar system.
What is the Milky Way (a Spiral galaxy)?
Astronomers measure deep space distances in light-years instead of kilometers or miles for this practical reason.
What is because cosmic distances are too vast, making kilometer numbers impractically large?
Edwin Hubble's observation that distant galaxies are moving away from Earth served as direct evidence for this cosmic condition.
What is the expansion of the Universe?
Clouds of dust and gas in space, where gravity pulls material together to form stars, are called this.
What is a Nebula?
When a Sun-like star consumes its core hydrogen fuel, it shifts toward this region in the upper-right of the H-R diagram.
What are Red Giants?
Arrange these three space structures from smallest to largest: Galaxy, Solar System, Universe.
What are the Solar System, Galaxy, and Universe?
Scientists determine the chemical composition of an unknown star by analyzing these dark lines in its light spectrum. Scientists determine the chemical composition of an unknown star by analyzing these dark lines in its light spectrum.
What are Absorption lines (or Spectral lines)?
This faint microwave energy detected uniformly in all directions of space is the leftover heat radiation from the early universe.
What is the Cosmic Microwave Background Radiation (CMBR)?
Compared to our Sun, a blue-white giant star has a surface temperature that is much higher and a lifespan that is much this.
What is shorter?
The dense remnant left behind after a low-to-medium mass star sheds its outer layers as a planetary nebula.
What is a White Dwarf?
Place the following five objects in exact order from smallest to largest: Universe, Star, Sun, Galaxy, Solar System.
What are the Sun, Star, Solar System, Galaxy, and Universe?
This phenomenon causes the wavelength of light from an object moving away from an observer to stretch toward longer, redder wavelengths.
What is Redshift (or the Doppler Effect)?
The abundance of these two light elements across the universe matches the mathematical predictions of the Big Bang model.
What are Hydrogen and Helium?
This single factor determines a star's evolutionary path, brightness, and final life stage.
What is initial mass?
Extremely massive stars end their lives in an explosive collapse called a supernova, leaving behind either a neutron star or a black hole.
What is a Black Hole?
This smooth, featureless type of galaxy typically contains older stars and very little gas or dust to form new ones.
What is an Elliptical galaxy?
If spectral lines from a distant star shift toward the blue end of the visible spectrum, it tells astronomers the star is doing this.
What is moving toward Earth?
Name all three major pieces of observational evidence supporting the Big Bang Theory.
What are the redshift of distant galaxies, the Cosmic Microwave Background Radiation, and the Abundance of light elements?