Galaxies on a Collision Course in the Hubble Ultra Deep Field Image

http://hubblesite.org/gallery/album/the_universe_collection/pr2004007d/

Stars, (including our sun) are spheres of hot, glowing gas.

Stars give off 2 types of electromagnetic radiation: visible light radio waves

Electromagnetic Radiation (Wave)- is a transverse wave that does not need a medium to travel through; therefore it is able to travel through space.

R.O.Y.G.B.I.V

Short wavelengths

Long wavelengths

All these waves can travel through space because they do not need a medium.

long short

high

R O Y G B I V

Wavelength (metres)

lowFrequency (Hz)

Spectrograph – breaks the light from an object into colors and photographs the resulting spectrum; this allows astronomers to identify the chemical composition and temperature of a star; each element has a unique set of lines on a spectrum

Astronomers infer how hot a star is by comparing its spectrum with the known spectra of elements at different temperatures. Stars at different temperatures produce different spectra.

 

Universe is defined as all of space and everything in it

Galaxy is a cluster of stars, gases, and dust held together by gravity

We are part of the

Milky Way Galaxy; nearest galaxy is Andromeda Galaxy

http://hubblesite.org/gallery/album/the_universe_collection/pr1994002c/

Spiral Galaxy NGC 3949

Distances to stars are SO large they are measured in light-years the distance light

travels in one year at a speed of 300,00 km per second or

9.5 million million km; light-year is a unit

of distance, NOT time!

http://www.daviddarling.info/images/Proxima_Centauri.jpg

Proxima Centauri is the nearest star (with the exception of our sun), it is 4.5 light-years away

Proxima Centauri is the nearest star (with the exception of our sun), it is 4.5 light-years away

Proxima Centauri is the nearest star (with the exception of our sun), it is 4.5 light-years away

Proxima Centauri is the nearest star (with the exception of our sun), it is 4.5 light-years away

1. Size

2. Color and Temperature

3. Brightness

Neutron StarWhite DwarfMedium size stars (our Sun)Red GiantsSuper Giants

SIZE: in order from smallest to largest

smallest

largest

Light Echoes From Red Supergiant Star V838 Monocerotis – September 2002

http://hubblesite.org/gallery/album/nebula_collection/

Our Sun is a medium size star- here it is compared to the planets in our solar system

– a star’s color reveals its temperature!

Ex. in the constellation Orion the Hunter, Betelgeuse is the red star in his shoulder (5, 500 o C) and Rigel is the blue-white star in his heel (over 15,000 oC)

Blue is the hottest

Red is the coolest

Ex. in the constellation Orion the Hunter, Betelgeuse is the red star in his shoulder (5, 500 o C) and Rigel is the blue-white star in his heel (over 15,000 oC)

Ex. in the constellation Orion the Hunter, Betelgeuse is the red star in his shoulder (5, 500 o C) and Rigel is the blue-white star in his heel (over 15,000 oC)

Ex. in the constellation Orion the Hunter, Betelgeuse is the red star in his shoulder (5, 500 o C) and Rigel is the blue-white star in his heel (over 15,000 oC)

Ex. in the constellation Orion the Hunter, Betelgeuse is the red star in his shoulder (5, 500 o C) and Rigel is the blue-white star in his heel (over 15,000 oC)

Ex. in the constellation Orion the Hunter, Betelgeuse is the red star in his shoulder (5, 500 o C) and Rigel is the blue-white star in his heel (over 15,000 oC)

AKA: brightness or luminosity or magnitude

The brightness of a star depends on its size and temperature

How bright a star looks from Earth depends on: 1. how far the star is from Earth AND 2. how bright the star actually is (absolute

magnitude)

Ex. in the constellation Orion the Hunter, Betelgeuse is the red star in his shoulder (5, 500 o C) and Rigel is the blue-white star in his heel (over 15,000 oC)

ABSOLUTE MAGNITUDE – THE BRIGHTNESS THE STAR WOULD HAVE IF IT WERE A STANDARD DISTANCE FROM EARTH

APPARENT MAGNITUDE – THE STAR’S BRIGHTNESS AS SEEN FROM EARTH; HOW BRIGHT THE STAR “APPEARS” TO BE  

http://stloe.most.go.th/html/lo_index/LOcanada9/907/1_en.htm

Stars don’t last forever. Each star is born, goes through its life cycle, and eventually dies. Astronomers study many stars and see how they differ from each other.

Crab Nebula

Horsehead Nebula

1. A large amount of gas and dust spread out in an immense volume in the nebula

2. In the nebula gravity begins to pull some of the gas and dust together and it becomes more and more dense.

3. The contracting gas and dust become so hot that nuclear fusion starts and enormous amounts of energy are released;

4. this is the earliest stage in a star’s life; a protostar

•a nebula is a large amount of gas and dust spread out in an immense volume Gravity begins to pull some of the gas and dust in the nebula together to form a ‘protostar’

Gas Pillars in the Eagle Nebula: Pillars of Creation in a Star-Forming Region

A Perfect Storm of Turbulent Gases in the Omega/Swan Nebula

The Cat's Eye Nebula: Dying Star Creates Fantasy-like Sculpture of Gas and Dust

The Spirograph Nebula

The Cone Nebula

Veil Nebula

http://hubblesite.org/gallery/album/nebula_collection/

How long a star lives depends on how much mass it has. Stars with less mass last longer than stars with more mass!

Small stars use up their fuel more slowly than large stars so they have much longer lives!

Small mass = long life large mass = short life

Medium-sized stars like the sun can live for up to 10 billion years- (astronomers think the sun is about 4.6 billion years old so it is almost halfway through its lifetime)

Ancient, White Dwarf Stars in the Milky Way Galaxy

White Dwarf, the final stage of a dying star, the bright white center is the star and the colors around is the gasses being expelled from the center

White Dwarf-the remaining blue-white hot core of a red giant after the outer part has drifted away

*about the size of Earth with the mass of the sun*have no fuel but glow faintly from leftover

Black Dwarf:

These are what remain

of a dead white dwarf

star after the heat has

radiated into space.

www.moonpebble.us/Images/BlackDwarf.jpg

Supersonic Shock Wave Heats Gas Ring Around Supernova 1987A

Gaseous Ring Around Supernova 1987A

SUPERNOVA

An explosion of a giant or supergiant some material expands into space and can become part of a nebula to form a ‘recycled star’

Details of Supernova Remnant Cassiopeia A

http://hubblesite.org/gallery/album/nebula_collection/

science.nationalgeographic.com/staticfiles/NG...

Neutron Star

a tiny star that remains after a supernova; a tiny star that remains after a supernova; a tiny star that remains after a supernova; a tiny star that remains after a supernova; a tiny star that remains after a supernova; a tiny star that remains after a supernova; a tiny star that remains after a supernova;

A tiny star that remains after a supernova

An artist's rendering shows a neutron star—located 50,000 light-years from Earth—that flared up so brightly in December 2004 that it temporarily blinded all the x-ray satellites in space and lit up the Earth's upper atmosphere. The flare-up occurred when the star's massive, twisting magnetic field ripped open its crust, releasing an explosion of gamma rays.

Dust Disk Surrounds a Massive Black Hole in Elliptical Galaxy

Black Hole-Powered Spiral Galaxy NGC 7742

BLACKHOLES: the remains of a massive star pulled into a small volume by gravity;

these are the most massive stars, 40x more massive than the sun; force/pull of gravity is so strong that nothing can escape, not even light

http://hubblesite.org/gallery/album/search.php?method=and&format=normal&sort=score&config=picturealbum&restrict=entire_collection%2Fpr&exclude=&words=black+hole&Submit=Search+site&page=2

graph used by astronomers; also called the H-R Diagram shows the relationship between the surface temperature and the brightness(magnitude/luminosity) of stars

Here × marks the sun

Most of the points form a diagonal band called the main sequence (this includes more than 90% of all stars) surface temperature increases as brightness increases

http://sunshine.chpc.utah.edu/labs/star_life/support/HR_init.swf

http://sunshine.chpc.utah.edu/labs/star_life/support/HR_animated.swf

http://sunshine.chpc.utah.edu/labs/star_life/support/HR_static.swf

A distant galaxy with a black

hole at its

centerAndromeda Galaxy

Our closest neighboring galaxy

http://hubblesite.org/gallery/album/entire_collection/pr2003015c/

Hubble's Sweeping View of the Coma Cluster of Galaxies

http://hubblesite.org/gallery/album/galaxy_collection/pr2008024a/

Types of Galaxies

Type Description of Shape Example

Spiral Galaxy

Arms that spiral outward, like pinwheels

Milky Way

Elliptical Looks like flattened balls;there is little gas and dust between the stars; most contain only old stars

Irregular Does not have a regular shape;Smaller than spiral and elliptical

The Large Magellanic Cloud

Barred Spiral Galaxy NGC 1300

Spiral Galaxy M100

Whirlpool Galaxy and Companion Galaxy

The Tadpole Galaxy: Distorted Victim of Cosmic Collision

Grand Design Spiral Galaxy M81

http://hubblesite.org/gallery/album/galaxy_collection/+1

Spiral Galaxy NGC 3949: A Galaxy Similar to the Milky Way

http://hubblesite.org/gallery/album/galaxy_collection/+1

science.nationalgeographic.com

NGC 1316, a giant elliptical galaxy formed billions of years ago when two spiral galaxies merged

Galaxy Centaurs A

Cigar Galaxy

: www.britannica.com

NGC1427A

Sagittarius Dwarf Irregular Galaxy

Moving Galaxies - Astronomers use information about how galaxies are moving as one way to develop ideas about how the universe formed. By examining the visible light spectrum of a galaxy, astronomers can tell how fast the galaxy is moving toward or away from our galaxy (the Milky Way). Only a few of the nearby galaxies are moving toward us, most are moving away.

Edwin Hubble, an American astronomer discovered that the farther away a galaxy is from us the faster it is moving away from us. The Hubble Space Telescope was named in his honor.

Origin of the Universe – Big Bang Theory states that the

universe began with an enormous explosion about 10 to 15 billion years ago. Since that explosion the universe has continued to expand. (p. 302, Fig. 20 and Fig. 21 on p. 303)

About 5 billion years ago, a cloud of gas and dust (nebula) collapsed to form our solar system