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Terene Lee
Semester Project Part1-3
The Signature Assignment Parts
Part 1: Star Identification:
The photo below is of the Lyra region of the milky way.
Pick 4 of the stars in the photograph below. Label each of these stars on the photo.
Then tell me the following things about each star:
1) Vega, Sheliak, Sulafat, Zeta Lyn
2) Vega : 25.04 / Sulafat : 620 / Sheliak : 960 / Zeta Lyn : 439
3) Vega : 1990 / Sulafat : 1395 / Sheliak: 1055 / Zeta Lyn : 1576
4) Vega : Sun*2.1 / Sulafat : Sun*15 / Sheliak: Sun*6 / Zeta Lyn : Sun*5.20
5) Vega : Sun*55 / Sulafat : Sun*5.5 / Sheliak: Sun*5.2 / Zeta Lyn : Sun*5.12
Vega
Sheliak
Zeta Lyn
Sulafat
photo of the Constellation Lyra
Part 2: Equation Analysis:
These equations are in your textbook so that should be a good source of accurate
information about them.
Equation 1: E = mc2
Question 1: Find out what the things in this equation
E is energy. M is mass. C is the speed of light.
Question 2: What is the size of c2?
C = 299782458 m/s
c2 = 89875517873681764 m/s
Question 3: Are mass and energy related? Answer yes or no and then provide a brief
explanation of your answer based on the analysis of the equation.
Yes. If mass doubles, energy will be doubled as well.
Question 4: Analyze the statement: “if it is possible to change mass into energy a little
bit of mass could produce a lot of energy”. Is it true or not? Provide a brief explanation
based on your analysis of the equation. It doesn’t have to be super complex and you
don’t need to “solve” the equation; just use the equation in a straightforward way.
Based on E = mc2, mass can turn into energy. This equation itself proves Energy
equals mass * (speed of light square). Mass is potentially energy.
The equation E = mc2 comes from the relativistic energy/momentum equation in Albert
Einstein’s Special Theory of Relativity (the book has a chapter on that theory). The full
relativistic energy/momentum equation is:
E2 = p2c2 + m2c4
…where the new variable p is the relativistic momentum (momentum at very high
speed). If an object is not moving its momentum is zero and the equation reduces to:
E2 = m2c4
If we want the energy E instead of the energy squared we can take the square root of
this equation to get:
E = mc2
Since this involves an object that is not moving this energy is sometimes called the rest
energy or energy of existence of an object.
Now this equation is technically not complete because when you take a square root you
get positive and negative solutions so it should really look like this:
E = mc2
This is a curious result as we will see from the following series of questions. Your book
on the chapter on Special Relativity may be of some help here and the internet definitely
will be useful.
The equation:
E = mc2
can actually be split into:
E = mc2
and:
E = -mc2
It’s this second equation we want to look at now, especially that negative sign. There is
something rather odd going on here. Let’s try to find out what it is!
Question 5. Is the mass m ever negative?
Like illustration said. theoretically, possible, however, not possible in scientific measure
as we can’t observe it. It’s theory not law. So No.
Question 6. Is c ever negative (hint: remember that c is a velocity and as such has a
magnitude and a direction. Positive and negative can be used to designate direction)?
Yes. If something is pushing against its direction where opposite magnitude.
Question 7. Can c2 ever be negative?
No. anything square is positive.
Question 8. Given your previous answers, can mc2 ever be negative?
No
We could multiply the equation by -1 and get:
E = mc2
Question 9. Is energy ever actually negative (can something have a negative energy of
existence)?
No. if there is no mass, no figure which produces no energy.
Question 10. Does energy ever have a direction (is it scalar or vector)?
No. Energy is ability to work. Not measurement of momentum
Question 11. Can the negative on the left hand side of the equation ever mean a
direction for energy?
No. There is no such thing negative energy.
Question 12. Some scientists thought that this negative sign was just a mathematical
oddity or scrap that had no physical meaning. Why might they think that? (use your
previous answers)
Energy is ability to work. How can ability to not work exist? Not measurable so I claim
negative energy does not exist.
Question 13. Is the negative sign actually meaningless or does this mathematical
peculiarity actually mean something? If so, what?
Whether it exists in real physics or only in concept, simplest form which is E = mc^2 is
not negative. So I think it is only conceptual thing not actual.
Part 3: Learning about a Law of Physics
Pick any Law or Principle of Physics in your textbook and:
1. List its name and give me an explanation of what it is and what it means.
Newton’s First Law of Motion – Inertia
It means moving object will continue to move(Inertia) when external net force is 0.
In other word, object will try to keep its motion whether is 0 or not.
2. Give me 3 examples in the real world involving the law or principle.
Example1. A soccer ball won’t move until I kick it
Example2. Car keep moves even I stop accelerating
Example3. When elevator starts to go down, I slightly feel light
Part 4: The Rare Earth Hypothesis and its Features
This involves the possible existence of alien life in the Universe. A net search should
bring up some immediate information on the subject.
1. Clearly and briefly explain the Rare Earth Hypothesis
It is hypothesis of arguing that the beginning of complex multicellular life requires
improbable combination of astrophysical number of events and situations.
2. List and briefly explain 3 important features of the Rare Earth Hypothesis (features
are ideas, concepts or facts that support the hypothesis)
1. Orbiting at the right distance from the right type of star
2. Perfect rotation axis regarding temperature
3. A large moon
3. Planets around other stars have been discovered in significant numbers (exoplanets).
What light has this shed on the hypothesis? Explain briefly.
It might sound like that Earth is not rare anymore but all those starts have almost 0%
chances to meet the circumstance where Earth has.
References:
http://www.constellation-guide.com/constellation-list/lyra-constellation/
http://www.nikomi.net/english/astronomy/starsizes.htm
http://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html
http://www.physicsclassroom.com/class/newtlaws/Lesson-1/Newton-s-First-Law
http://www.theguardian.com/science/2000/jul/20/technology2