09 LMS Activity 1
Süžeeskeem Tekst
- Discussing what the Special Theory of Relativity is
- Rodger: Woah Sally. We're on the moon! This is exciting!Sally: Don't get too excited Rodger. We're here for a reason. I'm going to teach you about special relativity. Rodger: Boooooorrrrriiiiing!Sally: *Rolls her eyes*
- Sally: Special relativity is a theory that connects velocity, time, and space. It is closely related to time in moving frames of reference. Although the speed of light remains constant no matter the frame, the perception of time is not necessarily always the same. One second on earth is not the same as one second on a spaceship in space that was moving at the speed of light because time in space would be longer than time on earth. The closer an entity's speed is to the speed of light, the slower time flows relative to time on earth.
- Sally: Building off of this information, we can now discuss what frequency shift is. Frequency shift describes the what color of visible light is seen whether an object is moving toward ("blueshifted) or away ("redshifted") from you. For example, a red light emitted in space from a spaceship moving at the speed of light appears blue on earth. Although the same number of waves appear in both locations, since the length of time is different in space and on earth, the frequency is different and therefore the color changes.
- I see blue!
- I see red!
- Sally: Now we can discuss space contraction and time dilation. Have you ever noticed that when you look up at a spaceship in the sky, it looks very small, but when you stand right next to it, it is huge. That happens because of space contraction. Space contracts parallel to the direction of a motion. Time dialation is when time passes more slow in a moving reference frame when compared to a stationary one. For example, on a spaceship travelling at the speed of light, while one year would pass by in space, 100 years would pass by on earth.
- 100 years later
- 1 year later
- Sally: Finally, we can talk about simultaneity and time, space, and causality. Events that appear to happen at the same time to you, might not appear to be simultaneous to me depending on our reference frames. According to Einstein, two events are simultaneous if they are equidistant from the source of light and the light from both events reaches the observer at the same time. Time, space, and causality deals with the fact that no information can travel faster than the speed of light. Aliens on a planet 165 million light years away from earth would see dinosaurs on the planet if they looked through a microscope!
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