The UniverseScience 8

Components of the UniverseThe universe is all of space and the matter that space contains.

The universe is made up of Galaxies, Nebulae, and Stars.

Nebulae•Large clouds of gas and dust that contract under the force of gravity, ignite, and form stars.

Components of the UniverseThe universe is all of space and the matter that space contains.

The universe is made up of Galaxies, Nebulae, and Stars.

Stars•Larger spheres of gas that release light and energy through fusion reactions.

Components of the UniverseThe universe is all of space and the matter that space contains.

The universe is made up of Galaxies, Nebulae, and Stars.

Galaxies•Large groups of stars and their planets that are classified by shape:•Elliptical – Oval shaped (football)•Spiral – Bulge in the middle with arms,

pinwheel-like (Milky Way)• Irregular – No definite shape

Classification of Stars

SizeSuper Giants – 1000-100 solar unitsGiants – 100 – 10 solar unitsMedium sized – like our sunWhite Dwarfs – the size of Earth of lessNeutron Star – 20-10 km in diameter

Classification of Stars

Composition•Determined by using a spectroscope•Emission Spectrum/Absorption lines•Most common elements are Hydrogen and Helium

Classification of Stars

Surface Temperature•Related to stars color•Red – cooler•Yellow – Average (our Sun)•Blue/white – hot

Classification of Stars

Brightness•Luminosity – the measure of light given off•Absolute Magnitude – the total amount of light given off by a star•Apparent Magnitude – how bright a star looks from Earth

Why do some stars look brighter than others?Can a star that is farther away look brighter than a star that is closer to Earth? How?

Classification of Stars

H-R DiagramHertzsprung – Russell Diagram graphs the relationship between absolute magnitude and surface temperature.

Types of Stars

Main Sequence StarsA star like our sun with average luminosity (brightness) and surface temperature.

Our Sun

Types of Stars

Red Giant•Upper right hand corner of the H-R Diagram•Bright because of their size (apparent magnitude)•Very cool temperature

Types of Stars

Neutron Star•Super dense core left after a supernova•1 tsp = 1 billion metric tons

Types of Stars

White Dwarf•Tiny, white hot core left from a star•Very old

Types of Stars

Planetary Nebulae• Expanding outer shell of a Sun-like star.•Contains mostly H and He, but has some heavier

elements in the core• Eventually expands out into the universe and becomes

available to make new stars (the universe’s way of recycling)

Types of Stars

Supernova•A star’s iron core that reaches 1.4X the mass of our

sun, so that gravity becomes strong enough to combine protons and electrons into neutrons•The core collapses into a single nucleus•The rest of the star rushes in and then bounces off the

nucleus with huge force causing a spectacular explosion.

Life Cycle of a Star

Nebulae toprotostar

Main Sequence

SuperGiant

Supernova

Neutron Star

Black Hole

Red Giant

Planetary Nebulae White Dwarf