The Universe 8.8A

The Universe The universe is all space and everything in it

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

Stars Stars are all different sizes and are made up of different elements

Stars Binary Star: Stars that revolve around each other, they look like they are blinking

Classifying Stars Stars are classified by three main characteristics: 1.Size 2.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 Stars Temperature 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 Stars Brightness 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

Hertz-Russell Diagram Main Sequence: 90 % of all stars, it is the diagonal band in the diagram

Galaxy Galaxies are made up of millions of stars, gases, and dust

Galaxy Galaxies are held together by gravity

Galaxy There are 4 different types of galaxies that are classified by their shape. – Elliptical – Spiral – Lenticular – Irregular

Draw these next to the pictures in your box (not in the giant white space that is for notes)

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 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

Irregular Galaxy No specific shape to the galaxy Disorganized shape

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: 4raY – Pre AP 4raY PI PI