• A star is:
– a huge ball of burning and exploding gases which gives off heat and light
– it burns for millions of years

• Star at the center of the solar system
• Huge ball of very hot gases, mostly hydrogen and helium
• Source of almost all of the energy on Earth
(plants, wind, weather)

• Brightness of a star
• Apparent magnitude – how bright it seems to be from
Earth, due to their
distance from the sun
• Absolute magnitude – how
bright a star really is

• Color of a star is a clue to its surface temperature
• Blue stars = hottest temperature
• Red stars = coolest temperature
• Main sequence
• A band of stars that includes most stars of average color, size, magnitude, and temperature

– Stars that increase in
brightness in the later stages of their existence
– A star that explodes
– Last Supernova in our galaxy was in 1604

• Scientists learn about stars by studying the
energy waves they send into space
• Use different kinds of telescopes