Moon Revealing Earth's Rotation 

Antoine OBannon great question - JW, can you explain? I can tell you my GPS tracking and scope isn't near the quality of yours but I don't even think it's possible to get a side to side view on mine. I'm lucky enough to keep it in frame - though I almost exclusively film in HD video and not photos...

You are quite right that it is impossible to tell who is orbiting who. But there is good reason for this. Strictly speaking, the Moon is not orbiting the Earth, nor is Earth orbiting the moon. Both objects are orbiting a common point called the barycenter. Wikipedia has a nice visualization of the barycenter of Pluto and its moon Charon: en.wikipedia.org/wiki/Barycenter. Because Earth is so much larger than the Moon, the barycenter actually lies within the volume of the Earth. The same goes for the Sun and all her planets.

RealSaladsamurai the barycentre gif reminds me of swinging someone around by the ankles.

We also have the background stars as reference points, including the sun.

This isn't general relativity; it's just fundamental Galilean invariance/relativity. It applies only to inertial reference frames - which means reference points that are not accelerating. Constant velocity is relative, and your claim applies when things are moving with constant velocity. However, if acceleration is involved, this is absolute. All observers can identify an object as accelerating when it is, so it is possible indeed to determine the true nature of this motion. Rotation is acceleration, and acceleration is absolute, ergo - it is the Earth rotating. The moon is also falling around us - meaning it is in orbit. If you go out on a night when the moon is out and note the position of the moon, then go out the next night at the exact same time (meaning Earth has rotated a full rotation), you will notice that the moon will be farther east than it was the night before (and lit by a slightly different angle). If you do this night after night, the moon will be farther and farther east, and eventually will not even have risen yet. After 27.3 days, the moon will return to its position relative to the background stars as it was the first night you went out. After 29.5 days, it will repeat the same phase (be lit by the same angle) as it was the first night. The reason for this discrepancy between the time it takes the moon to orbit the Earth relative to the background stars and the time it takes to repeat the same phase is because the phase depends on the angle at which the sunlight strikes the moon as observed from Earth. In the 27.3 days it took the moon to orbit the Earth relative to the stars, the Earth had orbited around the sun some, so the moon needs an extra couple of days to be back in the same Earth-sun position. All of this motion can be explained very easily with orbital mechanics - which is nothing more than ballistic trajectories. The Earth orbits the sun, the moon orbits the Earth. These orbits follow extremely predictable and calculatable paths. The notion that it is possible that the Earth is stationary and it is all the other things in motion would require a mess of illogical motion that is unexplained by any known physics. And this is even if you are only talking about the moon and sun. When you involve all the other planets, things become so hectic that you would have to fabricate contradicting explanations to explain it all and reconcile to a motionless Earth.

Thank you!

When you're tracking with your telescope mount you compensate the rotation of the earth. This is why we get round stars in a long exposure. If you just stop the tracking of your mount the stars or the moon will slowly get out of the field of view. You can see how fast the earth is spinning around her axis. Remember: The stars are not moving, you are!

planck cobe an wmap probes disprove da copernican principle

​@JWAstronomy1 there is no evidence that the earth is moving. All of this is based off assumptions and philosophy. I know you dont mean bad because you dont know.

@@iankrog8there is proof that revolves

@1millionviews673 lol, are you smarter than Einstein? Because He and several other revolutionary scientists disagree.

Thanks!

They do

They do, Smarty pants?

The motion of the clouds are depending on the wind direction it doesn't have anything to do with the earth's rotation (in this case). When you look up at night and see the stars and the moon you'll see a slight difference in their location with time. This is because the Earth is rotating and the stars standing still on their position. In this video you can see the velocity of the Earth's rotation by looking at the moon. They're not moving, we are! Hope this helps a little.

J.W.Astronomy It does help a little - but as you can see just about everyone replying is having a difficult time understanding how this proves the rotation of the Earth. I wish you'd do a full video to explain this one. I've done this for years myself and to be honest your replies are too textbook for me to just believe at face value, no offense intended: your work is some of the best out here without question. It's the quality and love that you can see in it.

JW how much nasa paying you for your BS come on man please be honest

Matthew Kingston about tree fiddy

@@matthewkingston8931 none