Light Clocks!

Just a small detour here. To understand what I said in the previous post, better lets look at a light clock. Well, what is a light clock? A light clock looks like this one below:

It is a little square carriage made of glass on wheels. At least this one is. Inside there are 2 mirror exactly opposite. One on the floor and the other on the roof. At the bottom mirror there is a light source. If you looked at the diagram it would make it clear in your mind. Yes, we have wheels on it. This is to conduct an experiement that will make it really fun!

We all know that Time= Distance/speed. That means if I was to go 100 miles at 50MPH. The time taken will be 2 Hours to complete that 100 miles. Simple.

In the light clock the distance light travels, is twice the length of the clock. That is light starts at the bottom, goes to the roof and then comes back to the ground. We also know that it will travel at 186,000 miles/second.

With a light clock,

Time= 2L/C. Where L is the hight of the clock and C is the speed of light. Which is 186,000 Miles/Second or 300,000 Kilometres/Second depending on which system of measure you want to use.The above sounds simple, and it is simple. The fun begins when the light clock it self moves. That is where Mr.Lorentz comes in. Again, read the post I had explained that in.

The Second Postulate of the Special Theory of Relativity

The second postulate of the special theory of relativity is very interesting and gives some unexpected results because it plays with frames of references. The postulate is: The speed of light is measured as constant in all frames of reference(If you are unsure as to what frames of references are, go back to a few posts, and I have explained it). Basically it is very similar to the first one, just that it comes out in a different form. If the laws of physics apply equally to all frames of reference, then light (electromagnetic radiation) must travel at the same speed regardless of the frame. This is required for the laws of electrodynamics to apply equally for all frames.

Think about it...it is a very strange and odd one. Here is one fact you can derive from the postulate: Regardless of whether you are flying in an airplane or sitting on the couch, the speed of light would measure the same to you in both situations. The reason that is unexpected is because most physical objects that we deal with in the world add their speeds together. Consider this, car with a driver and passenger is approaching you at a speed of 50 miles/hour. The passenger pulls out a slingshot and shoots a rock 20 miles/hour at you. If you measured the speed of the rock, you would expect it to be traveling at 70 miles/hour (the speed of the car plus the speed of the rock from the slingshot). That is, in fact, what happens. If the driver measured the speed of the rock, he would only measure 20 miles/hour, since he is already moving at 50 miles/hour with the car. Now if that same car is approaching you at 50 miles/hour and the driver turns on the headlights, something different happens? Since the speed of light is known to be 186,000 miles/second, and if we convert that into an hour we get 669,600,000 miles/hour. Coommon sense tells us that the car's speed plus the headlight beam speed gives a total of 669,600,050 miles/hour (50 miles/hour + 669,600,000 miles/hour). The actual speed would measure 669,600,000 miles/hour, exactly the speed of light. To understand why this happens, we must look at our notion of speed.

Speed as we all know is the distance traveled in a given amount of time. For example, if you travel 60 miles in one hour, your speed is 60 miles per hour. We can easily change our speed by pressing or releasing the accelerator in the car. In order for the speed of light to be constant, even if the light is "launched" from a moving object, only two things can be happening. Either something about our notion of distance and/or something about our notion of time must be out of line. If we look at what really happens it turns out, that both are lot of line. Remember, speed is distance divided by time. Think about it, and you will know what I am saying.

That is enough to think about for the time being. I am going to introducing this very gently, just to make sure our gray matter does not get into a twist!!

Relatively Mythical stuff....

Just to clear the air about somethings. Special Relativity is a playground for the mind. However, it is not some of the things I have listed below. 1. Time slows down as speed increases. Remember, we were talking of reference frames. Within a single reference frame that does NOT happen. Only when one reference frame is viewsed from another does all this take place. What that simply means is that on earth time never slows down as speed increases! 2. Objects get shorter as speed increases. The same rule as above applies here. 3. Special Relativity does not handle acceleration. That is the biggest myth about SR. 4. Mass increases with speed. In reality it is energy that increases and not the rest mass. 5. Nothing travels faster than the speed of light. What SR says is that crossing the light barrier either from a faster or slower speed is not allowed.

The long and Winding Road to Relativity

I started this blog to work on Dark Energy and Dark Matter...from there I skipped to relativity with one's grandmother playing a role. Let me explain, for one to understand Dark E and M, it is best that relativity be understood to some extent. My final goal is to hit on Dark E and M. Between that relativity and a few other stories might come in. For the time, we will focus on relativity. Just to remind readers that I have not 'lost the plot'

Relatively Thinking...

A good place to start maybe is to understand the first postulate...where on earth do I start? Frames of reference is what we need to understand. Let me find a grand mother to explain this to. Will be back!