Why Stars Shine
A star is made mostly of these two gases:
Hydrogen and helium
The term astronomers use to describe the brightness of a star.
Magnitude
What is the apparent magnitude of the star Sirius?
-1.4
The distance that light travels in one year.
Light-year
The temperature deep inside a star
15,000,000°C
How bright a star looks from earth.
Apparent magnitude
Which star is brighter: a star with a magnitude of 1 or a star with a magnitude of 0?
A star with a magnitude of 0. The smaller the number, the brighter the star.
One light-year = ____________ kilometers
9.5 trillion
Name an ancient group of people who studied stars.
Egyptians, Greeks, Chinese, and Native Americans.
How bright a star actually is.
Absolute magnitude
Which star is hotter: a red star or a white star?
White star
How fast is the speed of light?
300,000 kilometers per second
Process by which particles combine to form a new particle.
Fusion
The two factors that affect the brightness of a star.
- Distance
- Energy
What color of star is the hottest?
Blue-white
Why do astronomers use light-years to measure distances to stars instead of using kilometers or miles?
Such numbers are so large that they are difficult to read and work with.
A star gives a continuous supply of _______ produced by fusion.
Energy
The star that has the most apparent magnitude.
The sun
Yellow
Which is the greater distance, the distance between two planets or the distance between two stars?
The distance between two stars.