Stars, Galaxies and Nebulae

Another state of Matter

• Solids, Liquids and Gasses

• Plasma—like a gas, except can be charged electrically

• In this plasma lamp, electricity and magnet form structures

Some common Plasmas

• Fire

• Lightning

• The Sun and other stars

What is a star?

• A Luminous Ball of Plasma held together by gravity

• Fueled by Nuclear Fusion

HydrogenHydrogen

Helium

And this electron escapes

A star begins

• With a collapsing cloud of material

• Mostly made of Hydrogen, the lightest, simplest element

• a photograph of the center of the Swan Nebula, or M17, a hotbed of newly born stars wrapped in colorful blankets of glowing gas and cradled in an enormous cold, dark hydrogen cloud.

One Nebula, two Nebulae

• Clouds of dust and gas (especially hydrogen) where stars form

• The Horsehead Nebula

A Gallery of Nebulae

• The Bubble Nebula

• The Eagle Nebula

• HH-666

• Also known as “the axis of evil in the Carina Nebula”

• Rossette Nebula

• Part of the Eagle Nebula

• Triangulum Emission Garren Nebula

• Cat’s Eye Nebula

• Red rectangle nebula

How do they take these pictures?

• The Hubble Telescope

• Launched in 1990

• Will stop working this year

Webb telescope

• Will be launched in 2013

• Will be beyond the moon

Galaxies• Huge

groups of stars,

• Star clusters

• Interstellar clouds

Types of Galaxies

• Elliptical

• Spiral

• A Barred Spiral Galaxy

Milky Way

• Our Home Galaxy!

• A Barred Spiral Galaxy

• Ring Galaxy

• Starburst Galaxies

• Stars form at a fast rate

How many galaxies?

• More than 170 billion

• 170,000,000,000

• More being discovered all the time!

How many Stars in a Galaxy?

• As few as 10 million (10,000,000)

• As many as 1 trillion (1,000,000,000,000)

Our Galactic Cluster is called The Local Group – it has about

30 galaxieshttp://csep10.phys.utk.edu/astr162/lect/gclusters/localg.html

Our Galactic Address!

Name -

Street, City, Postal Code -

Continent -

Planet – Earth

Star – the Sun

Galaxy – Milky Way

Galaxy Cluster – The Local Group

Dark Matter

• We can’t see it

• But it has gravity– a lot!

• Makes up 90% of galaxies

• Something scientists are trying to find out about right now

?

Black Holes

• A place from which nothing can escape

• Not even light!

• Very compact mass in a deformation of spacetime

Supermassive Black Hole

• What it sounds like

• At the center of most, if not all, galaxies

• Here, an artist has imagined a supermassive black hole tearing a star apart

Supernova

• A star explosion

• Burns all its material in a few weeks or months

Red Giants

• Towards the end of a star’s life

• Expands to 9 times it size

• Starts to fuse carbon, neon, silicon and oxygen

• This star is Betelgeuse

Collapse

• Will eventually collapse into a “planetary nebula”

• Remnants may be recycled into new stars

Quiz-time!

• What element is being fused in the sun and other stars to make energy and helium?

• Hydrogen

• What do we call gas that can be electrically charged?

• Plasma

• Some examples?

• Fire, lightning, stars

• What do we call a region of clouds of gas where stars form?

• a Nebula

• The plural?

• Nebulae

• What is the name of this nebula?

• The Horsehead Nebula

• What will not let anything escape, not even light?

• A Black Hole

• What is a star explosion called?

• A Supernova

To Know for Midterm

Astronomical Unit – distance between planets

Light Years – distance between stars and galaxies

Star

Nebula

Galaxy

The End