Transcript The Big Bang - South Webster High School
The Big Bang
The Big Bang
ESS 9.2
ESS 9.3
Current Leading Theory… What is the ‘Big Bang’?
The Big Bang Theory is a picture (model) of the evolution of the universe that postulates its origin from a hot, dense state that rapidly expanded to a cooler, less dense state.
SUPPORTING EVIDENCE
1) The universe is expanding.
Hubble and Humason observed red shifts in the spectra of other galaxies and made the important discovery of cosmic expansion.
“Red Shifts” indicate that other galaxies are moving away from us.
Though a calculation involving the supposed distance of far-off galaxies and their red shifts, an estimation can be made as to how long the galaxy has been moving away from us. In turn, this number can be used to turn back the clock to a point when the two galaxies were in the same place at the same time, or, the moment of the Big Bang. This calculation is almost exactly the same for every galaxy that can be studied – Approximately 15 Billion years.
CONTINUED The universe is expanding We have observed this for some time. Now imagine running it backward in time. All the galaxies and matter in them eventually come tightly together. This compression heats matter and radiation to a very high temperature. (10,000,000,000,000 K)
Note: -273.15
°C = 0 deg K
Big Bang Model Imagine the universe expanding from this initial state, so hot that it expands in a rush like an explosion - hence the name "Big Bang" for this particular picture of the universe.
The universe cooled slowly.
Scientific Evidence 1. Universe is expanding “Red Shift” As the universe expanded, its density and temperature decreased. (Have you ever noticed how letting compressed gas out of a container makes it colder it because the gas expands and it loses energy?)
Note: -273.15
°C = 0 deg K
2. Cosmic Background Radiation Bell Laboratory scientists observed this cosmic radiation left over from the Big Bang in 1964. The radiation matched exactly with what was predicted by the Big Bang model theory, and it is spread evenly throughout space around us.
COBE – COsmic Background Explorer satellite
Very subtle variations of the cosmic background radiation were predicted by the theory, but only confirmed recently when a sophisticated satellite (COBE) was launched into space that was sensitive enough to confirm this part of the theory.
3. Primordial Hydrogen and Helium Found NASA has made some astounding discoveries which lend themselves to the proof of the Big Bang Theory Astronomers using the Astro-2 observatory were able to confirm one of the requirements for the foundation of the universe through the Big Bang.
In June, 1995, scientists detected primordial helium, such as deuterium, in the far reaches of the universe. These findings are consistent with an important aspect of the Big Bang theory that a mixture of hydrogen and helium was created at the beginning of the universe.
From the Big Bang Until Now
Misconceptions
Big Bang Theory - Common Misconceptions
There are many misconceptions surrounding the Big Bang theory. For example, we tend to imagine a giant explosion. Experts however say that there was no explosion; there was (and continues to be) an expansion.
Rather than imagining a balloon popping and releasing its contents, imagine a balloon expanding: an infinitesimally small balloon expanding to the size of our current universe.
There was no “Before” Another misconception is that we tend to imagine the singularity as a little fireball appearing somewhere in space.
According to the experts however, space itself didn't exist prior to the Big Bang. The singularity didn't appear
in
space; rather, space began inside of the singularity. Prior to the singularity,
nothing
existed, not space, time, matter, or energy - nothing.
What’s “Outside”?
So where and in what did the singularity appear if not in space?
We don't know.
We don't know where it came from, why it's here, or even where it is. All we know is that we are inside of it and at one time it didn't exist and neither did we.
1.
HOW OUR UNIVERSE AND SOLAR SYSTEM WAS CREATED ACCORDING TO THE BIG BANG THEORY.
A SINGULARITY BEGAN TO EXPAND 2.
CLOUDS OF GAS AND DUST (NEBULLA) WERE PRESENT
CONTINUED 3. BECAUSE OF NEWTON’S LAW OF UNIVERSAL GRAVITATION, THE DUST PARTICLES COMBINE 4. THE LARGER THE PARTICLES GET THE MORE GRAVITATIONAL PULL THEY HAVE SO THEY GROW. (MORE DUST PARTICLES GRAVITATE TO THEM)
CONTINUED 5. THE LARGEST BECOMES THE PROTOSUN AND THE OTHERS (PROTOPLANETS) BEGIN TO ROTATE AROUND THE SUN BECAUSE OF THE COREOLIS EFFECT
CONTINUED 6. THE PROTOSUN GETS SO LARGE AND ITS GRAVITAIONAL PULL GETS SO STRONG THAT HEATS UP AND THE HYDROGEN BEGINS TO GO THROUGH NUCLEAR FUSION.
7. THIS FUSION GIVES OFF SO MUCH ENERGY THAT IT CAUSES THE PROTOSUN TO IGNITE.
CONTINUED 8. THE IGNITION OF THE SUN IN OUR SOLAR SYSTEM CAUSED A SOLAR WIND TO BLOW AND BLEW MOST OF THE GASES OFF OF THE FIRST FOUR PLANETS MAKING THEM THE ROCKY PLANETS.
Before Copernicus gave us the heliocentric theory it was thought the earth was the center of the solar system. Why did everyone think he was crazy for this theory he proposed?
NUCLEAR FUSION ESS 9.1
A nuclear reaction is different from a chemical reaction. A chemical reaction involves a rearrangement of an atom’s outer electrons, while a nuclear reaction involves a change in the nucleus. In a nuclear reaction one element can change into another element something that would be impossible in a chemical reaction
In a nuclear fusion reaction, two light atomic nuclei fuse together to form a single heavier nucleus of a new element.
The process releases enormous quantities of energy.
Fusion reactions only occur at very high temperatures such as those found in the sun and other stars
For two nuclei to fuse they must come very close together.
H He H 1 H + 1 H 2 He
At the normal temperatures found on the earth the positive nuclei repel one another so strongly that this cannot happen. + +
At very high temperatures the nuclei are moving much more quickly and collide with so much energy that this repulsive energy barrier can be overcome. Once the nuclei are close enough the strong nuclear forces which hold protons and neutrons together in the nucleus take over and the nuclei fuse. 2 H 3 H He
n
Nuclear fusion reactions take place in the gas clouds of stars and result in the formation of new elements.
When two hydrogen nuclei join together by nuclear fusion hydrogen turns into helium. The energy released causes the gas cloud to glow
All naturally occurring elements including those found in our bodies originated in stars as a result of nuclear fusion reactions.
Soooooooo The processes in the stars have led to all elements larger than hydrogen and helium.
Where does nuclear fusion happen?
25% 25% 25% 25%
1.
2.
3.
4.
earth. sun. space. Nuclear plants.
1 21 2 22 3 23 4 24 5 25 6 26 7 27 8 28 9 29 10 30 11 31 12 32 13 14 15 16 17 18 19 20
What process is responsible for making all elements larger that hydrogen and helium?
25% 25% 25% 25%
1.
2.
3.
4.
Nuclear fission. Nuclear fusion. Radioactive decay. oxidation.
1 21 2 22 3 23 4 24 5 25 6 26 7 27 8 28 9 29 10 30 11 31 12 32 13 14 15 16 17 18 19 20
Which of the following is evidence that supports big bang?
25%
1.
Abundance of H and He.
25%
2.
Red shift.
25%
3.
Cosmic background radiation.
25%
4.
All of the above.
1 21 2 22 3 23 4 24 5 25 6 26 7 27 8 28 9 29 10 30 11 31 12 32 13 14 15 16 17 18 19 20