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Transcript of The Universe
whole galaxies revolve around the center of the galaxy
contains millions to billions of stars (and even more planets)
galaxies are not spread evenly but grouped into clusters and superclusters stars are like humans. They are born, live and die The universe we see from earth is actually in the past what does that statement mean? it takes light time to travel in space.
The sun is about 8.3 light-minutes away. The light that hits our face was actually produced 8 minutes ago A light year is 9.5 X 10^12 km. This is a measurement of distance to see how far away objects are in space. driving a light-year in a car moving at 65 mph would take more than 10 million years. Why do we need such a large unit to measure distance? As we look into space, we see the past... The universe is HUGE! most of it is empty space.
no air and no air pressure in space. Between stars there is literally no matter and is "empty". Big Bang Theory but two main types All matter and energy condensed into a small point and exploded in all directions. Estimated to have occured 13-15 billion years ago There was no time and no space before the big bang. out of this nothingness came the vast expanse of space, time, matter and energy. Theory is based upon scientific evidence and exploration Creationism All matter and energy in the universe created by someone or something theory based upon faith in higher power This is where science and theology collide The universe is expanding due to the initial explosion.
the Doppler effect helps explain this! Cosmic Background Radiation A dim background radiation can be detected throughout the sky. Uniform and seemingly coming from no source... as the cop car gets nearer, it has a higher pitch (higher frequency).
the distance between two wave fronts is smaller as it moves towards you
as the cop car gets farther, it has a lower pitch (lower frequency)
the distance between two wave fronts is greater as it moves away from you the change in frequency of a wave when the source of the wave or the observer are moving. the source is producing one sound or wave at a CONSTANT SPEED. but the distance between each successive wave changes as it moves. their is a change in the frequency of electromagnetic radiation (aka light) that is emitted from stars. if stars are moving towards us their light would be shifted to a shorter wavelength. This is called "blue shift" because the color blue has shorter wavelength and higher frequency. if stars are moving away from us their light would be shifted to a longer wavelength. This is called "red shift" as the color red has longer wavelength and smaller frequency. as the star moves towards us, its light is shifted to blue wavelengths/frequencies.
as the star moves away from us, its light is shifted to red wavelengths/frequencies. Edwin Hubble and other scientists observed (through data) the light emitted from other galaxies. what do you think they found? most galaxies have a red shift in light and galaxies farther away have greater red shifts in light. What conclusions can be drawn from this data? galaxies are moving away from each other and the universe is expanding.
If we take time in reverse, all the galaxies must have been closer together earlier in time.
the universe was contained into a very small space and there was a "Big Bang" of an explosion. At the very beginning of the expansion of the universe it was really really HOT.
this would have emitted radiation throughout the universe where do these microwaves come from? Best plausible answer...
was created when the universe began first done by scientists Arno Penzias and Robert Wilson in 1965 but many scientists have viewed this... as the universe cooled after the initial expansion the background radiation is now observed to have a temperature of about 3 Kelvin. estimated to be more than 100 billion galaxies!!! The Milky Way if we traveled away from the milky way galaxy, what would we find??? We would find other billions of galaxies, some similar to the milky way and some not so similar gravity holds everything together in space...
gravity forms stars and it is the gravity which holds everything together that makes up a galaxy what would space look like without gravity? 3 types of galaxies Spiral Galaxy Elliptical Galaxy Irregular Galaxy This is the Milky Way
a large bulge is at the center (nucleus) being very dense with many old stars (appears red, not as inergetic)
spiral arms extend out from the nucleus with gas and dust between the stars.
this "interstellar matter" is the stuff which new stars are made from. Appears blue (more inergetic)
many astronomers think a large black hole is at the center of the milky way and many spiral galaxies No spiral arms, spherical or egg shaped
usually have a reddish color.
must contain older stars with little interstellar matter to make new stars no regular shapes
no well-defined structure What are stars? large sphere of hot gas that emits light (electromagnetic waves) formed from clouds of gas and dust and go through different stages as they age We know things about stars due to the amount of energy the star is producing. Nuclear fusion power. How do stars work? How do they produce Energy? Held together by gravity When two small elements collide and FUSE together, forming larger nuclei.
This releases energy every time this process occurs
Remember this can only happen at extremely high temperatures! How do we have 91 elements that can be found in nature? All the elements that we know, have been created in stars due to nuclear fusion...
Smallest elements were created/existed at the beginning of the universe (H & He).
All larger elements have been formed due to nuclear fusion.
H + H --> He
He + He --> C
C + He --> O
Ne + He --> Mg What do we know about stars? How much energy does a person have when they are 5?
When they are 95? A star has life as long as fusion takes place. As the fusion inside of a star decreases, the star is growing older Why do some stars appear brighter than others? Apparent brightness has to deal with temperature, size and distance. Temperature of a star has to deal with the color of the star
What would a hot star look like?
What would a cool star look like? Why are hot things blue?
Why are cooler things red? Blue --> Yellow --> Red cloud of gas and dust
collapses to form a star Why would the gas and dust collapse? stars have different sizes
large amounts of H & He for fusion reactions (they have a lot of fuel)
Stable as long as they have enough fuel Fusion reactions decrease (less fuel) in the star
star will contract and then expand As more H & He are depleted, star will contract and outer layers expand outer layers eventually leave the star
not enough energy to fuse elements
slowly cool, about the size of earth more massive red giant
hotter and fuses heavier elements which accelerates life cycle Huge, bright explosion
occurs when fusion stops in a red supergiant Remnant of a supernova
very small in diameter but very dense/high mass
pulsate radio waves a remnant of a supernova
compressed matter which is so massive and dense that not even light can escape
cannot be seen directly but are detected by observing light and x rays which revolve rapidly around them. main sequence star (prime time of its life)