Moon Phases 2019 - Northern Hemisphere - 4K 

That really was something else. I listen to it when doing physics degree work and it makes me feel like I'm solving the Universe haha!

It's all about "music for 18 musicians" for me

what video was it, i'd love to check it out

Lol who gives a st.

You can - check out our Dial-A-Moon site: svs.gsfc.nasa.gov/4442

Because when you look at things upside-down, the directions switch.

Kaloyan Stoychev the images of the moon are mirror images of each other. the moons are showing the same surface area but different shadow patterns

@@susansutton1712 They are not mirror images. The image of the moon you see in the Southern hemisphere is a 180 degree rotation of the one in the Northern Hemisphere. The shadows move the same way, but because you are literally looking at the moon upside-down, they appear to be coming form the opposite side.

Perhaps a bit late, but since no one else answered: It's called tidal locking. Look it up, it is fascinating :)

Michael Dam Olsen I will look it up. It’s just hard for me to understand why we can not really feel motion or see motion on a grand scale. We only can detect motion here on the ground. For example when we walk, run, ride in a plane, a car, a train, a boat....etc. I know there are things that move slowly as well like a turtle, snail, sloth , trees,plants when the grow etc... So for the most part we can detect motion or see motion. But when it comes to the moon and the distance it is at it looks as though it is standing still, not rotating on its own axis, kind of like a clock. A clock facing us so we can tell what time it is. And the irony here is that the ancient people did use the moon as a clock. “Many moons ago” you know. Is their any experiments we can do at a smaller scale to demonstrate this motion and how it works? But I will look at what tidal lock is on the mean time.

@@leonardleija8968 I really like the way you think about physics and astronomy. Whenever we feel motion, what we are actually feeling is the CHANGE in motion. Either by speeding up or slowing down, or by changing the direction we are moving in (which is actually also just speeding up or slowing down, in specific directions that are not aligned with our direction of travel). Minute Earth made a video about tidal locking which is pretty easy to follow. I am not sure links are allowed, but in the address bar of your browser, replace the part after v= with this: 6jUpX7J7ySo I am thinking about an experiment you can perform on a small scale, but it is not easy because it is internal friction in the Moon that slows it down gradually. It has to be big for that to have an observable effect. Or did you just mean to simulate it's movement only, as it is now? That I can probably make some suggestions for.

Michael Dam Olsen one thing I forgot to mention as well is when standing still and also feeling motion not just seeing it. I suffered years back a hearing loss and it began with vertigo and tinnitus. I had the sensation of spinning even with my eyes close. You know everything spinning but you. Ha Ha! I think people who get intoxicated can demonstrate that very well after several drinks. Anyway just wanted to add this to my earlier comments.

@@leonardleija8968 Sorry about your hearing loss! The video I suggested does have captions if that helps. Motion is a vague term for things that are not standing still. To better understand what happens around us, it is useful to distinguish between smooth uniform motion in a straight line, and a path that curves with the moving object speeding up and/or slowing down. Smooth uniform motion is called "constant velocity" in physics. The difference between speed and velocity is that velocity has an arrow that points in the direction of travel, the length of the arrow is the speed. If this velocity arrow (vector) changes at all, then we talk about acceleration. It is the acceleration we feel, not the velocity. You can convince yourself of that by looking at a cup of coffee in a moving train. If the train is moving down a straight track at constant velocity, the coffee is perfectly still in the cup. But if the train follows a turn, coffee starts rising up in the cup, on the side facing away from the turn. Likewise, if the train slows down to stop, the coffee will rise up on the front facing part of the cup. If you were in a closed box on that train, with a cup of coffee and a light, then you would not know if you are moving or standing still, while the train is on the straight track at constant velocity. But as soon as you would see the coffee move up one of the sides of the cup, you would know that there was acceleration. This is apparently similar to how our inner ear senses motion, but I am not good with anatomy, so won't go into details. However, while in that box in the train, you cannot tell if the coffee rising is due to a turn or due to a slow down or speed up of the train. You can also not tell (supposing that the train can accelerate smoothly, and the tracks are not bumpy) whether you were standing still before, and are now moving, or if you moved before and now stopped. All you can really tell is that there was a CHANGE in velocity; an acceleration. Going back to our inner ear, it seems to work in cooperation with our other senses. If the ear tells us we are accelerating, but our eyes cannot see any signs of movement, then we often get vertigo or nausea. In this box in the train, that might be a problem. This is why it helps people that get driving sickness to sit in the front, so the eyes can confirm the movement. At least that is what I was told :) The Moon moves in a very long orbit around the Earth. It is so big that a small segment of that orbit would look almost exactly straight to you, unless you could measure it very precisely. So, the change in the velocity of the Moon, as it slowly turns a bit to the left, to avoid coasting away from the Earth in a straight line, is very small. The force that is causing this slight acceleration is of course gravity. So, while it is moving very fast, it does so in an almost straight line, so it doesn't feel much acceleration at all. Likewise here on Earth, in the orbit around the Sun. Except, the Earth moves even faster around the Sun than the Moon does around Earth, but in a much larger orbit. So in the end, it also feels very little acceleration. Much less than we humans could sense directly. It is amusing to think about the orbit of the Moon around the Sun. It is a weird corkscrew kind of pattern. If you just saw that without seeing the Earth, you would be very surprised. But then you would actually be able to predict that the Earth must be there, and how massive it is. If you want to experiment with tidal locking, you could do something with a bucket of water. It is not exactly the same, because the forces involved are not due to gravity. But go find one of those merry-go-rounds for kids that you can spin by hand. If you take a bucket of water and stir it a lot so the water is swirling around in it, and then place it on the m-g-r, you are set up to use friction in the water to affect the spinning water in the bucket. Start turning the m-g-r to a reasonable speed. After a while, the water is not swirling in the bucket anymore, it is simply rising on the side away from the center of the m-g-r (don't place the bucket at the center). If you have a control bucket on the ground that is swirling the same amount at the start, you will see that it swirls a lot longer than the one on the m-g-r. That is the sort of dissipation of energy that caused the Moon's spin to slow down to match it's orbital speed. Actually, if the Moon was spinning slower than it was orbiting, tidal forces would speed it up instead. This is why we see so many tidally locked orbits in our solar system, once it gets to the "right" speed, it will be locked in, because that is where there are the least tidal forces. In the solar system those forces are caused by gravity, in the water bucket experiment, it was caused by you applying force to the m-g-r to start it rotating. Not sure if that is helpful at all, but feel free to ask if I messed up explaining something :)

@Κωνσταντίνος Γεωργούλας I thought I'm the second loool, Hi from UAE