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Gotta Blog…

17 Aug

The fascinating thing about science is that, no matter how well I think I understand something, I always get revelations when I hear a different perspective. This perspective from a book that I am reading (Five Equations that changed the world – Michael Guillen) on einstein’s (and 4 other scientists) life is too difficult to pass. The fact that I am writing about it makes me feel like I have understood it better, though, I am pretty sure I will blog something that looks very similar as time progresses. But, this one is a “gotta blog” thing… (Title has been used)..:)

What was the fundamental problem that einstein solved? There are 2 parts to this question. During einstein’s time, there was a big confusion on how speed is measured. Also, there was a confusion of the way mass and energy were related. As we all know, speed is measured by distance covered divided by the time taken. This holds true as long as you are a stationary observer. What if you are moving too? If so, people thought that objects appeared to move faster or slower based on whether you move towards the other object or away from it. For example, if an object moves at 100 metres/second speed and if you are moving towards or away from the object at 1 metres/second, then you will observe that the object moves at 101 metres/second or 99 metres/second. As long as you account for your speed, the speed of the object is constant. The only exception to this principle was that, scientists observed that the speed of light remained constant irrespective of how the observers moved. That was the puzzle. Why is it that speed of light remains unchanged? Einstein started out with the premise that, light speed is absolute and doesnt change. When the observer moves, his notion of space changes. What it means is that, what is 1 meter for a stationary person isnt the same if he is moving at some speed. Then, the question is, how much does space shrinks/expands by? He found that it is equal to 1 – (0.5*v^2/c^2). What it means is that, if you are travelling at say, half the velocity of light, 1 meter shrinks to 0.875. Since the velocity at which objects move in earth is very small (even speeds of the order of 1000mph), the shrink factor is so small to be negligible. If one travels at the speed of light, the universe shrinks to 0 which doesnt make sense. So, einstein concluded that it is impossible to travel at the speed of light…

The next question was about mass and energy. Before einstein, the law of conservation of mass and energy had already been proven. But, no one knew how mass end energy were related. They seem to vary similarly under different conditions, but yet, the unifying knot wasnt identified. All conservation laws states is that, you can’t destroy energy or matter. When you seemingly think you destroy matter, you just transform it to a different form. Thinking along similar lines from his space-time theory, einstein discovered that mass/energy expands (the reciprocal of space/time) as an object moves faster. If you think from that perspective, you would notice that, if a body travels at the speed of light, its mass should be infinity, which doesnt make sense either. But, it also affirms that a body cannot move at the speed of light. Anyway, what einstein did was to calculate the kinetic energy difference between a stationary particle that emits radiation with a particle that moves at a speed of ‘v’ and equated it to the amount of radiation emitted. This boils down to the equation 0.5 (R/c^2)*v^2 where R is the radiation energy emitted. Since kinetic energy is 0.5*m*v^2, he reasoned that the mass lost due to radiation should be equal to R/c^2 which infers that m = E/c^2 => E = m*c^2… When I started typing, I thought I was all clear… But now, I am not… I will let someone in the group to enlighten the last part of this blog…:)

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6 Comments

Posted by on August 17, 2007 in From AM-KICKING blog

 

6 responses to “Gotta Blog…

  1. Mad Max

    August 17, 2007 at 2:45 pm

    reads interesting but needs more careful reading…comments (if i have any) reserved for later today..

     
  2. Survivor

    August 17, 2007 at 6:28 pm

    I read it and was further enlightened after some serious discussion with Mindframes. One question though..

    “what einstein did was to calculate the kinetic energy difference between a stationary particle that emits radiation with a particle that moves at a speed of ‘v’ and equated it to the amount of radiation emitted.”

    How ?
    I already talked to you about this anyway. Maybe, others might have read something about it too..

     
  3. Manohar

    August 17, 2007 at 9:29 pm

    No answer to your question. Actually I didn’t understand the question- perhaps you can word it differently?

    But on the topic- a few insights I had obtained when reading about einstein’s special theory of relativity and later the general theory.

    One of the interesting outcomes of the Michelson-Morley experiment; Imagine Mindframes is travelling at the head of a speeding ray of light and seeing him go out of house so fast, Survivor decides to jump on another speeding ray of light in the same direction? obviously both of them are travelling head to head at the speed of light- what would be the velocity difference between them?

    Answer is not zero- but again the difference would be the speed of light. This is what caused utter chaos with the results of the michelson-morley experiment- which had started out to prove something completely different.

    Now the interesting thing about Einstein’s special theory of relativity is that- it doesn’t explain this phenomenon. As in nobody knows why (as in mechanism) this is true. Instead what Einstein did was turn it around and made that an assumption on which his special theory of relativity is based upon.

    So if both think they are travelling at the speed of light and there still exists a relative velocity between them that is still equal to the speed of light- obviously what the way the measure the speed of light in their relative frames have to be different.. v=d/t. so their concept of distance (in the direction of motion) and time have to be different.

    Now the lynch pin of this theory is that the relative velocity between that at speed of light is speed of light. If somebody proves this wrong- there goes the special theory of relativity.

     
  4. Manohar

    August 17, 2007 at 9:32 pm

    And before anybody thinks I came up with that example– NO.
    Refer to ‘The dancing wu-li masters’ for such delightful interpretations and more.

     
  5. Mad Max

    August 18, 2007 at 6:11 pm

    Allrighty. I read this article umpteen number of times and the comments. Super interesting stuff (blog and Mano’s comment) but somewhere along the line I’m lost (lol).

     
  6. Manohar

    August 19, 2007 at 5:41 am

    @mad max: I don’t want to hijack suresh’s blog, but the gist of my comments is simple.

    1. Imagine you and your buddy are running at 6Mph. Whats the relative speed of you both? zero, would ofcourse be correct.

    Now
    2. Imagine you both are running together at the speed of light (damn- you are fast). The problem now is that- newtonian physics observations fail. Although both of you are running at the speed of light in the same direction (parallel to each other). The relative velocity is not zero as expected. The relative velocity between you two is the speed of light.

    Einstein was the first person to turn it on its head, and instead of explaining it; took it for granted and came up with a theory which explains what must be happening if that observation is true.

    and hence the special theory of relativty.

     

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