What Causes The Phases Of The Moon? 

I think partly it's due to how close people think the moon is to earth (check out that vid if you haven't see it already). If the moon were that close, it would be tough not to cast a shadow on it.

2:20 Thank goodness you started talking, I was getting blinded by the light in the background.

Who else had to do this for school? 👇🏼

Dear Southern Hemisphere, Please stop depicting the moon upside down. Regards, Northern Hemisphere

Guys. The "wHo eLsE iS heRe fRom ScHoOL" comments are old just stop dude

The statement is not contradictory because there are times when the Earth, sun and moon line up, even though the orbital plane of the moon is tilted at 5 degrees relative to Earth's orbital plane around the sun. These are the rare eclipse events.

it is more or less, isn't it? You can have a new moon around sunset or sunrise but not in the middle of the night because you're right, it would be on the opposite side of the Earth

Nobody: Not a single soul: Me: FURRY MICROPHONE!

1. true 2. yes 3. no - the moon is tidally locked to the Earth, meaning it rotates on its own axis once in the time it takes to orbit Earth. This keeps the same side always facing Earth - check out tidal locking on wikipedia if you want to learn more.

I had no idea that so many folks (like, a shocking number) thought that lunar phases were caused by Earth’s shadow

@theFounder87 Yes, yes it does. Once a month, which is why the same side always faces us. This is no coincidence, it's due to something called 'Tidal Locking' - check it out on wikipedia if you want to know more.

✨ethic✨00:50

Yes, and then if one were to guess, it seems like a reasonable guess. When there is a crescent moon, sometimes you can still see the dark side a bit. If the Earth was close and casting a shadow, you'd more likely have some light reflecting off of the Earth onto the Moon and back.

Neat. When my daughter was in elementary school, her class had a project where she demonstrated this for class. She stood in front of the projector (the sun) and held a play ball (the moon) in front of her head (the Earth) at arms length. She was able, with the teacher's help, to show this by moving around the projector and spinning while doing so. If you say that your eyes are your hometown, and the moon is where you see it at night, it makes it quite easy for kids to understand this way.

Sir today I saw inverted moon during day time why moon looking inverted at that time

It was so nice to watch a science video that posed a question to which I actually knew the answer.

Hi! I really like the videos you make! You explain better than other videos I've seen around, much better than my physics teacher.. I have a request/suggestion for a video, that'll explain something alot of people make mistakes about: circular motion (an object moving in a circle, both vertically &horrizontally), like clearing the fact that despite a vehicle is moving in a circle in a "constant" speed, it's still accelerating because it constantly changes direction. Just a suggestion, thanks!

0:58 this guy doesn't believe in lamps

Teachers always make you watch old videos

Being forced to watch this video by school, damn teacher using an old mf video

Thank you for posting this. It makes so much sense and I no longer believe what I did about the Earth's shadow.

this explanation this guy has given nearly killed me... i couldn't stop laughing the crap out of me until i fall off the chair!...LOL

@mreueujj1 Just to clarify this: the "dark" side IS periodically illuminated (when it's facing the sun). But we can't see it because it's facing away from us. So it's better described as the "far" side of the moon.

Interesting... He did quite a nice job explaining this.

I'm doing this for school but I can't complain, it's very nice

No continue awesome video

“Theres only one source of light in the solar system.” Meanwhile my light bulb!

I'm really ashamed that I didn't know the right explanation before. But now I know thanks to you...

I hate when teachers make us watch this stuff.

It's quite funny. I really been studying astronomy and astrophysics for 2 years. And I never understood how come we have the lunar phases. But I guess no more! Thank you so much! Andy.

So, in short, all sides of the moon see the sun but only half of it sees the earth

1. Yes. 2. Yes. 3. No. Let me explain. The moon has a synchronous rotation, which means "moon day" is exactly as long as the "moon year" (the rotation of its own axis takes the same time as the orbit time around Earth). Therefore, all on Earth is seeing the same side of it. You can, however, see an other side of the moon if you go to the moon, of course. :)

I explained this to a friend yesterday who studied ASTROPHYSICS, she also believed it was the shadow of the Earth. Being a nerd is hot ;)

@1veritasium Your explanation is incorrect. The Moon is divided into two hemispheres: the nearside and the far side (what people call the "dark side"). The nearside is permanently locked facing the Earth because when the Moon was formed its liquid core was pull by Earth's gravity towards one side. This is why the Moon is smoother on the nearside. The Moon's hemispheres have days and nights just like Earth, only longer. The night side (the true dark side) will move as the Moon orbits the Earth.

I love that OP responds to most comments ^.^ I want to know how many people you sampled at the start and how many responded correctly, stating that the phases are caused by the sun facing a different side of the moon to that which the earth is facing, and how many people stated it was due to the earth blocking the sun. I would have expected most people to know the correct answer.

why do we have to assume that life, if it exists else where, has to do it the same way as on earth. the whole respiration = photosynthesis and protein etc

EXACTLY! well said! i mean, there are over 100 BILLION solar systems in our galaxy alone, and then there's something like 40 billion galaxies in the universe! and how do we know this is the only universe?! for us to be alone would be more incredible than for us not to be.

Hello Teacher!

Some schools do teach that it is the shadow of the earth... Honestly that is what I was taught while in school, though it never sounded right to me.

Yo if you’re watching this because of school remember it please. I just solo argued against like 5 people and pulled this video up after not getting through to a single one.

Hey comment section, get off the acid.

I always thought it was common knowledge that the phases of the moon were caused by us only seeing what was lit by the sun.

yes science class online

That first woman might know how to cook a roast dinner, but she's totally clueless about what causes the phases of the moon. I'd say she'd be struggling to explain what causes the seasons as well, lol.

Wait if the redness of the moon is caused by diffraction and blue light scattering as the light passes through the atmosphere, why isn't the moon and sun always red as the light always passes through the atmosphere?

this makes me wonder if people even *HAD* science class when they were a kid

i'm surprised most people think it's based on how much shadow the earth casts on the moon. Is that what the textbooks really teach, or is this because it's the kind of info most people don't think about, and therefore misremembering what they heard from 5th grade science class?

@zwirlo If you have ever noticed before. The New moon is always the hardest thing to find because it's almost right next to the sun. If you have ever seen a new moon you only get to see it for half and hour ( depending on what season. ) after the sunset. As it waxes ( goes towards full moon. ) it slowly that's to be more in the night instead of the day.

This really helps alot to my test tomorrow literally.......

Can we talk about how we were just 5 degrees away from potentially NOT having a full moon (or moon in general). 🤔😳

@zwirlo you can't see a new moon at night

So.... What about the "Dark side of the moon" when we are on the school, the teachers says that there is one side of the moon that can never be seen from the earth, Are you destroying my childhood (Again)?

I want to know why sometimes we see the moon come up late in the sky! as late as 1-2 AM and sometimes it comes up at 5 pm!!

sir i have a question the moon eclipse stays only for 2 or 3 hours.....but why......❓❓❓ we know that at moon eclipse night the moon almost stays behind the earth....So the moon eclipse should remain all night...........🤔🤔🤔

Does Tidal Locking apply to all moons and planets? Or is it just our moon? Does distance matter?

Well bugger me, I'm ashamed to admit i was one of those people before watching this video

But, a nice thing to note is that the moon certainly looks different in other places. I remember being in Nepal, and the crescent moon was not like ( and ) but tilted about 90°, that's why the moon in their flag is tilted 90° so it looks kind of like a bowl. So, is it tilted a full 180° if I were to travel to New Zeeland? (I live in Norway, and New Zeeland is pretty much on the exact opposite side of earth from here. And we both have fjords.. Coincidence? I think not...)

0:35 "is that about the sun and the moon.....uuhhh" wow, she's so smart it blows my mind.

The dark side the moon refers to the fact that it never is in the line if sight of earth, ie out of radio contact to the apollo astronauts(that's why it was referred to as 'dark'). The 'man' on the moon is always facing earth because when the moon was cooling, all of the heavy materials in the molten glob were pulled to the side facing earth due to gravity. All of that lopsided mass keeps that side facing us. The moon's day(1 rotation) is 28 earth days. One full cycle of its phases

Yes! I knew the correct answer to this one!

Why the shadow is coming from the right down "corner" (in reality the shadow comes from left down) But I still don't know why the shadow is coming from the opposite direction of the"actually" movement of the Moon in the sky....I know that the Moon is actually trying to stay more in view but the Earth's rotation speed overwhelms it . So is it because of the movement of Moon itself? 1 rotation every 28 days? Isn't that to slow ?

Hold on a second. You mentioned that the lunar cycles are based entirely on our perspective of a half illuminated moon, and not the earth's shadow because the lunar orbit is on an axis 5 degrees out of what would have caused a shadow. I'm not disputing that. You did, however, also mention how lunar (and solar) eclipses ARE due to the shadow. This seems to contradict itself. Is this because the axis changes, or because we occasionally see different perspectives on that axis?

I have to show this vid to my drunk dad because he's freaking out

I agree the "5 degrees" can be confusing, so here's a different explanation. Let's say you have a piece of paper with a drawn model of the Sun and Earth, with a circle (or ellipse) showing the orbit of the Earth on the paper. Half of the month, the Moon is over the paper, and the other half, it's under. Twice a month, it passes through the paper, but only rarely does the point where it passes trough line up with the sun and the earth (which would cause an eclipse).

so by just looking at the color of a planet we can see if we can live on their?

Great video thanks !

if you asked the same question to people in the US no one would know the answer

Who else here had a sh*tty sub for science on their second day of school and had to read a freaking article for each question? (if you were in my class you’d understand)

I was about to answer wrong at first but I caught myself in time. \o/

Holy crap, I watched the same lunar eclipse from Perth. Going out with binoculars to a field and waiting a few hours for that spectacular glimpse of a complete lunar eclipse.

play the video at 1.5 1.75 or 2 to get it done quicker

so sky is blue because blue light or color is scatterd and during sunrise or sunset the sun appears red as blue is scattered by the sky so what do we see the scattered light or non scattered light because in both cases blue is scattered but for sky we see blue for sun we see red can u please make this clear? by the way your videos are amaizing!

Technically there is no "dark side" of the moon, but there is a "far side". During a new moon, for example, the moon appears black to us meaning the side we usually see is the "dark side", and the "far side" is now a full-moon facing away from us.

@MegaSHUCHITA During most full moons, the moon isn't directly behind the earth, it's a bit above or below (explained from 1:50 in the video) so the sunlight doesn't go through the earth's atmosphere on its way to the moon.

Why is it possible to always see the moon? - During the day and during the night. Wouldn't there be a time where the moon is not facing certain areas of the earth? Or is it just the location where I live the allows me to always see the moon?

How do new moons occur at night? Wouldn't it always be daytime to those who observe them?

I got like 43 seconds and I'm going "No, no, no, people! The phases are caused by the moon casting a shadow on itself. Earth does the same thing, we call it 'night'" I'm sorry. I'll keep this video in my queue and finish later. Right now, "The Daily Show" awaits.

@mathfeel well spotted - I just reread that in horror. Sometimes I reply to posts late at night when clearly I'm not firing on all cylinders

Actually, if you think about universe as infinite, which it most probably is, you can say there is infinite amount of planets on which there is life. Even more interestingly, if there is infinite amount of them, there can be a planet that is almost (or even exactly) like ours. In fact there is infinite amount of such planets. That's the beauty of infinity, that you can divide it into infinite amount of infinities. :D

When people say a Full Moon "causes" Himan Behavior to change is strictly JUST a visual prejudice...we always have a "full moon"

So does it mean if you are standing on the moon during Luna eclipse on Earth, from the moon will you see that the earth is red, because the Earth's atmosphere scattered all of the shorter visible light wavelengths only lights with longer wavelengths are able to pass through the Earth's atmosphere toward to moon and reflex back to the earth?

I thought the ocean tides caused the phases of the moon :p But seriously, it is quite simple: phases of the moon are caused by shadow of the moon on *itself*. Basically, from Earth, we partially see the side that is lit, and the rest of the surface that is dark. Lunar eclipse is when Earth casts a shadow on moon. And solar eclipse is caused by shadow of moon on the Earth. And how about shadow of earth on itself? Well - that is what we call "night" :) So you can also think of phases of the moon as due to seeing "part of the day-side of the moon, and part of the night-side". Have you noticed that when there is no full-moon, when the moon is waxing/waning, you can still make out the shadowed part of the moon dimly? Any guess to why is that?

So to use this looking for a planet similar to Earth, you would have to be looking at a planet's moon during an eclipse?

3:02 that means earth is not a blue planet to the moon or other objects in the outer space??

I can't seem to find or understand much information on the internet about the difference in distance between the earth and the moon and how long it takes for the moon to get from the farthest place to the closest place to the earth. Your explanations please.

I just want to say I'm a huge fan of this channel! This stuff is actually pretty cool! In the beginning of all of these videos I feel so stupid and by the end I actually understand the stuff he's saying (most of the time). Thanks Derek!!!

I was thinking that we have always a lunar eclipse each month but we called lunar eclipse to that when it is not normal and repetitive.

besides, simetimes, in non full moon night, you can see the part of the moon whitch doesn't recive the light from the sun because it's receving light from the earth. Anyway I think that when you interview people you select only the ones who give the wrong Answare. I don't think people are so ignorant... although I tried to ask the some questions to people I know, and they gave the wrong answare too :(

so ray scattering makes the sky blue?

Very interesting :)

@zwirlo You can't actually see a new moon...It's just a black patch in the sky (that is if you have a telescope or if you know the stars very well in order to figure out what's missing from the sky)

Why does everyone get so catch up on there being the need for water on a planet for there to be life. Doesn't this limit our exploration of the the universe and possible other 'mediums' which life may exist? That is, a non-carbon based life without the need for water.

@jmxbox I agree BUT life itself it's a very improbable thing....But if is not life somewhere else that would be an incredible waste of space.

I will do and thanks for replying! Helped out alot :)

oh my goodness!!! I study astronomy HOW COME PEOPLE DONT KNOW SOMETHING SO BASIC!! O_O

@lamadre420 the thing is we don't really have any examples of other life that is not in need of water, so we look for water because it is the most likely place for life, not that there can't be mercury based life but it will probably be more likely that they are water based

Wow. I haven't watched the video yet, only read comments. And the amount of people who think NASA are lying...

I can almost GUARANTEE that there is other life out there in the universe. I mean when you think of the constants of the universe and the amount of possible distances of stars to planets and also the amount of solar systems in the universe, there has got to be a solar system in which an Earth sized planet is the exact or similar distance from a star like out Sun and can support life. AT LEAST one.

Skip to 0:53 to skip past all the random people giving the same wrong answer

our teacher made us watch this lol