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What are main laws of quantum physics and some other questions

  1. Jun 9, 2005 #1
    My questions are next:
    1.What would happen if you try to travel with spacecraft exactly at the speed of light?
    Yes, I do know that when spacecraft trie to reach the speed of light its mass will increase immensely...,my question is what would happen to the spacecraft that is trying to achieve speed of light,beside its mass would immensely increase?

    2.Do photons have mass at all? I've heard that only massless particles can travel at exactly the speed of light.And I also heard that photons,despite they don't have rest mass,have the mass of momentum or something like that-what does it mean?

    3.Will humans ever reach faster-than-light(FTL) speeds with spacecrafts?
    Don't foget just for how many things humans have said that it would be impossible-like flight into the space was considered to be impossible!
    My question is also,does light travel at the same speed(300 000km/s) like in classic physics?
    I can't see anything going faster than light,since laws of the universe will not allow us,also no speed has been discovered that is faster than light?Since everything in the universe can't pass light speed,I can't see how is possible to travel faster than light-also how would an spacecraft survive faster than light trip???

    4.My question is does quantum physics allow to anything to travel faster than speed of light?

    5.What are major differences between quantum physics and classic physics?

    6.I've heard that energy,according to quantum physics exists only in quanta-small pockets of energy,which means energy is not continous-I honestly don't believe that energy can be created or destroyed in practice(in theory maybe),despite what some physicists say.Even if you had no matter,you would have vibrational energy,as well you have the vibrational energy of the absolute zero.
    Any opinions?

    7.Quantum physics and zero-point energy-Has zero-point energy ever been proven?
    Is it possible to have free,unlimited energy from zero-point energy?
    Has zero-point energy ever been proven in practice(well,according to experiments of many,many inventors whose results were that they had energy from nothing,you know that there was some kind of zero-point energy)?
    From what I know there are a lot of inventors and inovators who actually created electricity from nothing(people like Thomas Henry Murray,Edwin Gray)),who ever of these inventors was close to the solution of our energy sources' problems was killed or dissapeared in mysterious circumstances.
    And also many inventors wanted to demonstrate to physicists,but physicits refused to give inventors any opportunity to prove their claims.
    Even physicists can make mistakes,that's why physics of today's world will eventually change,at least partially.
  2. jcsd
  3. Jun 15, 2005 #2
    1. You couldn't, according to todays knowledge, it would need an infinite input of energy, but you could get awfuly close.

    2. AFAIK, photons do not, they but since they have energy...energy can be mathematically converted into mass, right now, we lack any 'logical' framework/picture to fit that into. Confusing isn't it?

    3. Yes! we will, I do not know how or when, but that is the whole point of learning the sciences for me (other than that they fascinate me ;)

    4. Tachyons, though they have never been detected, are like a photons conjugate, they travel instantaneously, and it would require infinite energy to bring them down to lights speed (according to more math). A lot of these discoveries seem to be people screwing around with formulas, then they find something to look for as a result of it. After that, they find what they were looking for, and modify any existing frameworks/pictures accordingly.

    5. Heh! I barely know classical physics...I mostly grasp concepts well, I barely know any of the formulas involved.

    6. I don't have enough time to write our a response to that...Sorry, but look up zero-point energy, and the cassimir effect. Other members could give you better direction, I am sure.

    7. Um, the cassimir effect. The only semi-credible device that I heard of that may or may not be able to produce 'free' energy was some kind of magnetic device. The thing is it was supposed to excite the domains in a vortex like fashion. For the same reason that tornados lower the ambient air temperature a bit, it was supposed to be able to convert a heat gradient into electricity. It was not 100% efficient, or anywhere near that number, even according to the author (who escapes me at the moment) It was just supposed to be a way to recover a little bit of heat loss.
  4. Jun 15, 2005 #3
  5. Jun 15, 2005 #4
    Weight, mass? Since when did we include a gravitational field?
  6. Jun 15, 2005 #5
    Ignoring the other crap posted on this thread:

    1. Your spacecraft would not be able to reach the speed of light. You must always realise that when talking about special relativity you need to put yourself in some reference frame. So, as far as you observe, the spacecraft gets heavier and heavier, and time appears to slow down *on the spacecraft*. As far as they're aware, your time appears to slow down.

    2. Photons have no rest mass. The relativistic kinematic relation is [itex]E^2=m^2c^4+p^2c^2[/itex]. m is the rest mass, and p is the momentum, so as photons have no rest mass (m=0) their momentum is equal to their energy. This expression is Lorentz Invariant, i.e. no matter what speed you're going when observing an object, this relation holds.

    3. No, special relativity forbids this (to get to the speed of light would need infinite energy).

    4. No

    5. The differences between QM and classical physics all stem from the quantisation of energy, and the mathematical formalisms used to describe the systems. Read up on Planck and Blackbody radiation, Einstein's papers of 1905, Bohr's work of 1913, Compton's work of scattering in 1922 and De Broglie's PhD these of 1924. Then you'll be able to see where modern QM stems from (Schrodinger and Heisenburg in 1925/26).

    6. Quanta means 'packets' of energy, it's the whole point of quantum physics. Energy is not continuous in certain bound states (atoms, harmonic oscillators etc). Energy can not be created or destroyed, nobody's saying that. It can, however, be freely exchanged with mass. How easy this is to do is another matter!

    7. Zero point energy is well tested. For example, the unexcited state of a simple quantum harmoic oscillator is [itex]\frac{1}{2}\hbar\omega[/itex]. This is an example of zero point energy that can be observed. To say that these 'inventors' created electricity out of nothing, and the the Physicists are hiding true invention is pure quackery. Electrical *ENERGY* comes from transforming, say, rotational *ENERGY* (such as in a dynamo). There is no energy created or destroyed, it merely is changed from one form to another.
  7. Jun 15, 2005 #6
    Out of interest, James Jackson, would you consider my posts to be "other crap"?
  8. Jun 15, 2005 #7
    No! They're clearly sensible...
  9. Jun 16, 2005 #8
    - Casimir-effect
    - Vacuum polarisation
    - Lamb-shift
  10. Jun 16, 2005 #9
    Well, probably my posts then?
  11. Jun 16, 2005 #10
    And Izer's too, I should imagine, although they seem to be gone from the thread now.
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