Transcript Stars, Galaxies, and the Universe

Stars, Galaxies, and the Universe
Carin Miranda
Smyrna Middle
Winter 2010
Stars
• Stars are made up of gases.
• When different stars are different colors it
means they have a different temperature.
• Blue-hottest
• Red-coolest
Stars
• The sun is a main sequence star.
• A star begins as a ball of gas and dust pulled
together by gravity.
Classifying Stars
Class
O
B
A
F
G
K
M
Color
Blue
Blue-White
Blue-White
Yellow-White
Yellow
Orange
Red
Temperature
Above 30,000
10,000-30,000
7,500-10,000
6,000-7,500
5,000-6,000
3,500-5,000
Less than 3,500
Sequence of Star’s Life
• Main SequenceRed GiantWhite Dwarf
• The H-R diagram shows the relationship of a
star’s surface temperature and its absolute
magnitude.
• A white dwarf is is a star that has used up all of its
hydrogen and is the leftover center of an older star.
• Class F stars are yellow-white
• The majority of stars in our galaxy are main
sequence stars.
Galaxies
• Scientist study distant galaxies because it takes a
long time for light to travel through space and to
learn what early galaxies looked like.
• Edwin Hubble has identified three major types of
galaxies:
– Spiral (our Milky way)
– Elliptical
– Irregular
Formation of the Universe
• According to the big bang theory,
the universe is about 13.7 billion
years old.
• According to the big bang theory,
cosmic background radiation filled
the universe after the original
explosion.
Formation of the Universe
• The universe is expanding
outward.
• Scientists think that the universe
will expand forever.