Gotta Blog...

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...:)