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I am a bit confused about this question.

“ At this moment, are you in motion relative to the sun? Explain.”
Please help out someone, thanks!

1 Answer

3 votes

How do you know when something is moving ? You ALWAYS have to compare it to something else. If the object in question changes its distance or direction from your house, or from your big toe, or from a stake in the ground in your front yard, then you say it's moving. The thing is: There's ALWAYS something else to compare it to.

I assume you're sitting on the couch now, staring at the TV, or at your computer, or at your phone. Compared to the couch, or to the tree in your front yard, or to somebody sitting on top of Mt. Everest, or to downtown Jerusalem, you're NOT moving. Your distance and direction from the reference point isn't changing.

BUT ... what if you compare yourself to somebody sitting at the North pole of the Sun ? He has to keep turning his eyes to watch you (because the Earth including you is in orbit around the sun). So your direction from him keeps changing, and 'relative' to him (compared to him), you're definitely moving.

Now let's go a little farther:

You're sitting in a comfy seat, reading a book that's in your lap. Maybe you're even getting sleepy. You're sitting still in the seat, and the book in your lap isn't moving.

SURPRISE ! Your comfy seat is in Row-27 of a passenger jet, and you're flying to Seattle to visit your Grandma. right now, you're just passing over Casper, Wyoming, and there's somebody down on the ground playing with a telescope. He looks at your airplane, and HE says that you, the seat you're sitting in, and your book are ALL moving at almost 500 miles an hour.

The difference is: YOU're comparing your book to the seat in front of you, and YOU say the book is not moving. The guy with the telescope is comparing the book to the ground he's standing on, and HE says your book is moving west at 500 miles an hour.

You're BOTH correct. The description of ANY motion always depends on what you're comparing to. If you're about to ask "What's the REAL motion of the book ?", then I'm sorry. There's NO SUCH THING as 'REALLY'. It always depends on what you're comparing to. Nine people can be watching the same object, and they can have nine different descriptions of its motion, and they're ALL correct. They're just comparing the object to different things in their own neighborhood, and the nine things are all moving in different ways.

The bottom line: MOTION IS ALWAYS RELATIVE (to something else).

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