Why does the night sky appear to move slowly even though the earth is rotating at 1,000mph?
In: Earth Science
Stars are really really far away although we are orbiting the sun quite fast. Its like when you’re driving on a highway, things closer appear to move faster and things way way way farther away dont move at all. Like a mountain in the distance. Its cause our field of view is so wide when we talk about light years, any movement looks stationary until we turn are heads 360 (earth rotating) đŸ˜†
Think about the hands of a clock. The closer to the center, the less distance the arm travels compared to the point of the hand, we know this because the circumference at the center is smaller than the outer edge, but the hand moves the same overall degree. While we are spinning at 0.0007 rpm(or .252 degrees per minute, pull out the protractor), the stars do not. So every degree we spin, the stars will appear to move. The reality is we aren’t watching the stars move, but realizing the shift in our own point of origin in comparison to rest of the universe.
They are far? You really are 5
To get a reference stand on the edge of a merry go round and move it so that it makes a rotation once a day.
Very slow.
But make it more relatable.
Take a watch with a second hand put in on the floor and walk around the watch at the same rate as the second hand.
How far did you walk?
Now go back to the merry go round and spin it at 1 rotation a minute
Walk around it at the same rate.
How far did you walk.
The bigger it is the more you walk and the faster you have to walk even though it rotating at the same rate as the watch.
Everything is miles and miles away. Thank a commercial aircraft flying between 460 – 575 mph airspeed through the air because of the distance from the viewer who is stood on the earth the aircraft would look slower due to the lack of reference points up in the atmosphere. Being an airspeed of 500 mph in the air would equate to a ground speed of around just 400 mph due to the curvature of the earth so there are more miles between point to point the higher up you go.
This has a lot to do with the relative frame of reference.
When you are in a vehicle you are in motion, however because you are inside it appears that everything around you is moving. This is why we don’t feel like we are hurling 1000’s of mph through space.
We also perceive closer objects to us, as moving fast than distant objects. Such as roadsigns vs mountains. Roadsigns seems to whip by on the highway, but restaurants and houses, other landmarks appear to pass us much slower.
Just like the view from one side of your car appears to be moving slower than the other when you look out of the window. Distance.
Ever watch a plane 5 miles in the sky whizz past hour field of vision going 300 mph? No? Me neither
Its like when you look out the side windows in a moving car. The stuff further away appears to move slower.
Same reason why flying at 30,000 ft the earth below looks like it’s barely moving despite you travelling at 600mph.
Mph isn’t really relevant when your only frame of reference is the insanely distant stars/moon/sun.
You’re travelling 24,000 miles around the earth at 1000mph so the entire reference background of the sky only moves 1/4 of a degree above you every minute.
If you positioned a 100% fixed rigid telescope to a foundation you could only catch stars in your line of sight so briefly (depending on how powerful your zoom is)
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