Needing a basic clarification with SR

• jam.muskopf
This leads to the concept of time dilation and velocity addition in Special Relativity and General Relativity. In summary, the conversation discusses the difficulty in understanding the speed limit in Special Relativity and General Relativity, and the concept of velocity addition based on the postulate that the speed of light is constant for all observers. This leads to the concept of time dilation and velocity addition in both theories.
jam.muskopf
I am new to understanding the concepts in SR and GR, and one of the main concepts i am having difficulty with is the speed limit. I don't understand why things can't already be moving at the speed of light in certain frames of reference. For instance, from the Earth's frame of reference, isn't it possible for something to be traveling c/2 in one direction and something else to be traveling at c/2 in the exact opposite direction, making the velocity from either object's frame of reference c?

No, look up velocity addition in wikipedia.

Thanks!

These equations on velocity addition are based off time dilation, correct?

jam.muskopf said:
These equations on velocity addition are based off time dilation, correct?

No, they are based on the postulate (or empirical observation) that all observers measure the speed of light to be c, regardless of their frame of reference.

What is special relativity and why is it important?

Special relativity is a theory developed by Albert Einstein in 1905 that explains how objects move at high speeds and in different frames of reference. It is important because it has helped us understand the fundamental nature of space, time, and gravity, and has led to many technological advancements such as GPS and nuclear energy.

How does special relativity differ from classical mechanics?

Classical mechanics, also known as Newtonian mechanics, describes the motion of objects at low speeds and in a single frame of reference. Special relativity, on the other hand, takes into account the effects of high speeds and different frames of reference, and shows that the laws of physics are the same for all observers.

What are the key principles of special relativity?

The key principles of special relativity are the constancy of the speed of light, the relativity of simultaneity, time dilation, length contraction, and mass-energy equivalence. These principles explain how time, length, and mass change for objects moving at high speeds, and how the laws of physics are the same for all observers.

How does special relativity impact our daily lives?

Special relativity has a significant impact on our daily lives through various technologies such as GPS, which relies on the principles of relativity to accurately determine location and time. It also helps us understand the universe and how it behaves on a large scale, leading to advancements in space travel and communication.

What are some common misconceptions about special relativity?

One common misconception is that special relativity only applies to objects moving at the speed of light. In reality, the principles of special relativity apply to all objects moving at high speeds. Another misconception is that special relativity contradicts Newton's laws of motion, when in fact it is a more accurate and comprehensive explanation of motion and gravity.

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