STAR GROUPS: STAR GROUPS Of the non-Hollywood variety


BINARY STARS: BINARY STARS Binary Stars are two stars revolving around each other which appear as one. (One third of the stars we see)


STAR CLUSTERS: STAR CLUSTERS Are groups of stars which stay close together


OPEN CLUSTER: OPEN CLUSTER An irregularly shaped group of stars


GLOBULAR CLUSTER: GLOBULAR CLUSTER A spherically shaped group of stars


GALAXIES: GALAXIES Vast systems of stars


ELLIPTICAL GALAXIES: ELLIPTICAL GALAXIES Oval shaped with a thick center (like the mirrored image of a fried egg)


SPIRAL GALAXIES: SPIRAL GALAXIES Huge bright central disc with radiating arms.


IRREGULAR GALAXIES: IRREGULAR GALAXIES Neither elliptical or spiral shaped.


Slide10: Our galaxy, the MILKY WAY GALAXY, is spiral shaped


Slide11:


Slide12:


The Doppler Effect: The Doppler Effect Astronomers can tell if stars are moving by studying their spectra. The DOPPLER EFFECT is the apparent change of wavelength when the object is moving toward or away from the observer.


One Shift Two Shift: One Shift Two Shift RED SHIFTS BLUE SHIFTS Wavelengths from a receding star (moving away from us) spectral lines get longer. Wavelengths from an approaching star spectral lines get shorter (Blue to you!)


THE BIG BANG THEORY: THE BIG BANG THEORY States that the universe began as a single cosmic explosion about 15 billion years ago.


Background Radiation: Background Radiation Energy left over from the Big Bang that is evenly spread out throughout the universe. This background radiation is one observation that supports the Big Bang Theory.


After the Big Bang: After the Big Bang Gravity began to affect matter racing in every direction. The clumps formed into huge clusters of matter. These clumps became the galaxies of the universe.


HUBBLES LAW: HUBBLES LAW The farther away the galaxy, the faster it is receding (moving away) from the earth.


Galaxies seem to be racing away from the center of the Universe.: Galaxies seem to be racing away from the center of the Universe. Every galaxy seems to be moving away from Earth. After examining the Red Shift that appears from distant galaxies astronomers conclude the universe is expanding at tremendous speeds.


Expanding Universe: Expanding Universe If the universe is expanding, then the objects near the very edge of the universe are the oldest objects in the universe. The most distant known objects in the universe are over 12 billion light years from the Earth and they are…


Quasars: Quasars An enormously bright object at the edge of our universe which emits massive amounts of energy. In an optical telescope, they appear point-like, similar to stars, from which they derive their name quasar = quasi(something like) stellar(star).


Quasars: Quasars Most studied and mysterious objects in the universe. Too small to be galaxies, they give off more energy than 100 or more galaxies combined.


Quasar: Quasar


Three Pieces of Evidence Supporting the Big Bang: Three Pieces of Evidence Supporting the Big Bang The presence of Background Radiation The observation of the galaxies spreading away from the center of the universe (Red Shift) Quasars at the edge of the universe first formed objects


What Happens Next?: What Happens Next? Astronomers feel that the Big Bang theory leads to two possible futures for the Universe.


Open Universe: Open Universe Galaxies will continue racing outward (continue to expand). All of the stars will die off as the last of their energy is released. There will be nothing left, total emptiness.


Closed Universe: Closed Universe Gravitational attraction between the galaxies will cause the movement away from each other to slow and, eventually come to a halt. The gravitational pull will begin to pull the galaxies back to the center of the universe.


Closed Universe cont.: Closed Universe cont. All of the matter and energy will again come close together and end in a central area (possibly no larger than a dime). Then another Big Bang will occur and the formation of the universe will begin all over again.


Um… I think we may have been here before. : Um… I think we may have been here before. This restructuring may occur once every 80 to 100 billion years.