Starlight
Do all colors come up in every star's black-line spectrum?
What is a nebula?
A cloud of gas and dust where a star begins.
What is a star?
A ball of gases that gives off a tremendous amount of electromagnetic energy.
What are on the X and Y axes?
X-Temperature, Y-Luminosity (brightness)
How does the color of stars seen from Earth differ from their actual color?
From Earth, stars appear as tiny specs of white light, but they actually vary in color.
Fusion continues until the core is almost entirely made out of what?
Iron
What is a light year?
The distance that light travels in one year.
What is the Hertzsprung-Russell Diagram? What does it tell us?
It is a graph that plots stars based on their luminosity and temperature. It shows the relationship between brightness and temperature.
What does a star's dark-line spectra reveal?
The star's temperature and composition.
What does the fusion of iron into heavier elements take?
Energy from the star.
What are the 2 most common elements in stars?
Hydrogen and helium
What type of stars run diagonally through the Hertzsprung-Russell diagram that extend from cool, dim, red stars at the lower right to hot, bright, blue stars at the upper left?
Main sequence stars
The stars have similar temperature and composition.
Fusion continues until the core is almost entirely made out of what?
Iron
What color are the coolest stars and what color are the hottest stars?
Coolest--red
Hottest--blue
Blue--their temperature is caused by vast amounts of nuclear fusion which requires energy
What does the fact that most distant galaxies have red-shifted spectra indicate?
That those galaxies are moving away from Earth.
What happens to the carbon atoms in a collapsing Massive Star as temperatures rise and fusion begins again?
The carbon atoms in the core of the massive star fuse into heavier elements such as oxygen, magnesium, or silicon.
What causes the circular trails of light seen in long-exposure photographs of the stars?
The rotation of the earth on its axis.
How do we know there are red giants and red super giants on the HR diagram?
They differ greatly in brightness, but have the same temperature.