Stars Galaxies and the Universe Mr Foxs Science

Stars, Galaxies, and the Universe Mr. Fox’s Science Class

The Basics • Galaxy – a grouping of hundreds of billions of stars. • Universe – billions of galaxies make up the entire… well… everything (to what we believe) • Light-year – the distance light travels in one year. 9. 5 million kilometers.

Classifying Stars • Main characteristics for stars size, temperature, and brightness. • Size – straight forward. Giant stars, or supergiant stars. – Betelgeuse – would fill up the solar system to Jupiter. • Temperatures – 3, 200 Celsius reddish color, 5, 500 Celsius white in color 10, 000 Celsius blue-white color

Classifying Stars • Brightness – the amount of light they give off • Apparent magnitude – brightness as seen from Earth. • Absolute magnitude – as seen if it were a standard distance from Earth. (blah where is the cool stuff Mr. Fox)

Star Life • (here we go) • Protostar – When contracting gases get so HOT that nuclear fusion starts to happen. • How long it lives depends on mass – Our star is a medium sized star, and it has been around 5 billion years, and still have 5 billion years left. • Stars are born in nebula, a giant cloud of gas and dust in space.

Star Death • When the star runs out of fuel, it will become one of three things. . – White Dwarf – a small blue-white hot core of a star that eventually burns out and becomes a black dwarf (which doesn’t give off light and is dead). As small as Earth. – Neutron Star – smaller and denser than a white dwarf. As small as a town on earth. – Black Hole – Gravity is so strong, because there is so much mass, that light cannot escape!

Black Holes • Simplified – they are caused when supergiant stars explode or supernova. • They suck in EVERYTHING that is near them, light, radio waves, matter… doesn’t matter. • Detected via X-rays in space from the gases being sucked into them. • Little is known about them, but much is theorized about them. • We believe there is a black hole that holds our galaxy and every other galaxy together.

Pulsars and Quasars • Pulsar – neutron star that produces pulses of radio waves. – In the 1960 s, they thought these radio waves were from extraterrestrial civilizations. • Quasars – objects that are 12 billion light-years away that looked like stars. – They are thought to be old galaxies. An extremely massive black hole surrounded by a halo of mass.

Home Work • Page 116 1 – 5 • Quiz on the Planets and Stars on Friday.

Some Facts • The more mass a star has the shorter the life. • The Sun, will become a red giant, before becoming a White Dwarf. Of the front 4 planets, only Mars will survive. • A young galaxy is called a Dwarf Galaxy.

Galaxy • There are billions of Galaxies out there, that all have differences to them • There are three main types of galaxies – Spiral Galaxies – Elliptical – Irregular

Classes of Galaxy

The Milky Way Galaxy • This is the Galaxy our solar system is in. • Our sun is about 30, 000 light years from the center of our galaxy. • It is estimated that our galaxy is 100, 000 light years wide. • Our Galaxy is a Spiral Galaxy

Milky Way Galaxy

Spiral Galaxy • A galaxy who’s arms spiral outward looking like a pinwheel or a buzz saw. • Andromeda is the closest galaxy to us, and it is also a spiral. PS: this galaxy is on a crash course with us…. . (more on this later)

Andromeda Galaxy

Other Spiral Galaxies Pinwheel Galaxy M 51

Elliptical Galaxy • A galaxy shaped like a flattened ball that only has old stars.

Elliptical Galaxies Galaxy M 87 with it’s Jet Galaxy M 32

Irregular Galaxy • A galaxy that doesn’t have a normal shape.

Examples Hoag’s Object (Ring Galaxy) Centaurus A

More Examples The Cart Wheel Galaxy (and some others there )

The Sombrero Galaxy (Ring Galaxy)

Galaxy Clusters • Sometimes Galaxies get close to each other and form a cluster. • They end up sharing some sort of gravitational point. • The Milky Way is in a cluster with 11 other Dwarf Galaxies • Dwarf Galaxy – a smaller galaxy that is a satellite of a larger galaxy. Sometimes they are what’s left when two galaxies collide.

Galaxies Move • The sun revolves around the center of the Milky Way. It takes 250 million years!!!! For it to make one revolution around it. • Galaxies were also discovered to move around in space. • 1920 s: Edwin Hubble discovered that the galaxies are moving within space. He saw that further a galaxy was from us, the faster it was moving away from us.

Galaxies Move • Galaxies can and will crash into each other. (WMP Video Here)

Collided Galaxies Antenna Galaxy

Collided Galaxies