the universe 8.8a. the universe the universe is all space and everything in it
TRANSCRIPT
Components of the Universe
• There are lots of parts of the universe:– Stars– Nebulae– Black Holes – Galaxies
And so much more!
Stars• Stars are large balls of
gas that create their own energy by fusing hydrogen atoms to create helium– The energy created by
fusing hydrogen atoms emits light and heat
Classifying Stars
• Stars are classified by three main characteristics: 1. Size2. Brightness (luminosity)3. Temperature
Classifying Stars
Size• Our sun is a medium size star (letter G below)
• There are stars in the universe large enough to fill our solar system
Classifying StarsTemperature• Temperature is determined by color– Blue: Hottest (20,000-50,000*C)– White (10,000*C)– Yellow (6,000*C)– Red-Orange (4,000-5,000*C)– Red: Least Hot (3,000*C)
Blue Red
Classifying StarsBrightness• Brightness depends on the
size and temperature of a star
• Brightness of a star is described in two ways– Apparent Magnitude: Brightness
seen from earth– Absolute magnitude: Real
brightness of a star from a standard distance
Hertz-Russell Diagram
• Nickname: H-R Diagram
• How does it help classify Stars?– Graphs the two most
important characteristics of stars: Absolute magnitude (brightness) and Temperature
Galaxy
• There are 4 different types of galaxies that are classified by their shape. – Elliptical – Spiral– Lenticular– Irregular
Elliptical Galaxy
• Looks like a flattened ball
• Characteristics:– Contain billions of stars– Little gas and dust
between the stars – New stars rarely form,
mainly old stars in these galaxies
Spiral Galaxy• Shaped like they have arms
spiraled outwards (pin wheel)• This is the type of galaxy we
live in
Lenticular Galaxy
• Galaxy with a central bulge or bar in the middle
• It might also have small arms
Black Holes
• Large objects that form dense gravity wells• Their gravitational pull is so strong, light
cannot escape it (hence why they are dark!)
Black Holes
• How can we see black holes:– We can’t– We observe them
by looking at the light and energy being sucked in
Black Holes
• Black holes have no volume, but infinite density!
• Videos: • http://
www.youtube.com/watch?v=3pAnRKD4raY – Pre AP
• http://www.youtube.com/watch?v=kfiU4ioZvPI