This is really just a fault in the English language. In Danish, we have the word "døgn" which means a full day and night or 24 hours, whereas in English only a day is used which can either mean the time where the sun is up or a full cycle of day and night aka 24 hours. Most people say that winter has the shortest day of the year because they mean day as in the time the sun is up, whereas you are talking about a day meaning 24 hours. In conclusion, winter has both the shortest and the longest days at the same time. Hurray for English.
I speak Russian and imo English has a real lack of a word to describe one 24-hour cycle. In Russian there's день (den' -day) and сутки (sutki - from midnight to midnight). I take it there's no such word in any germanic language?
That, at the same time, the frustration that comes with gathering knowledge as well as the core reason why we're able to gather knowledge at all: figuring stuff out is always harder and more time consuming than comprehension of what others have figured out.
Mind blown! I’ve been wondering why the sunrise and sunset turn around at different months. I’m still not sure I grasp it, but I get the general impression of what you’re saying anyway! Thanks for that!
I wanted to check what day was the longest, but I could only find articles about the sun solstice. Then I remembered that there was a minutephysics video about it. Thanks, Henry!
Azivegu Lol, for me it gets bright at 6 and dark at 6. But there are too many trees near my house and thanks to them its cold as fuck even in the afternoon
1:18 The explanation used here for describing the role of the obliquity of the ecliptic in determining the length of day is practically incomprehensible. Here is a more intuitive explanation: 1. For observers on the Earth, the Sun appears to move eastward along a path relative to the background stars called the ecliptic; this path is due to the Earth's orbit around the Sun. 2. The Sun appears to move eastward along this path, partially counteracting the Sun's apparent westward motion due to the Earth's rotation and making the day take longer. 3. At noon during the solstices, the Sun appears to move exactly eastward along the ecliptic, maximally counteracting the westward motion and making the day take the longest. 4. At any other time of year, the Sun's motion along the ecliptic is not only eastward, but slightly diagonally up or down in the sky as well. 5. This up-down motion means that there is less eastward motion available to take away from the westward motion of the Sun. 6. During the equinoxes, the ecliptic is the most tilted at noon compared to any other time of the year, which means that there is the least amount of eastward motion available to counteract the westward motion of the Sun, making the the day the shortest. Viewed from the Sun: during the solstices, the rotational movement of the sunlit portions of Earth is antiparallel to the orbital motion of the Earth, while at any other time of year, the motion is at an angle and counteracts the orbital movement less.
+BirdValiant Yes, you've explained the obliquity effect about as well as I can imagine. Although it would be nice to avoid it, I keep coming back to the perspective where the observer is on Earth, seeing the apparent movement of the Sun against a background of stars. A daily snapshot of the Sun at the same time each day reveals a vector shift by about a degree every day along the ecliptic. That daily relative velocity vector can be split into two components at right angles to each other. The vertical component, parallel to longitude, results in daily, cumulative creep of the Sun north or south, causing a change in daylight hours. The latitude component results in eastward creep and change of season. If one ignores eccentricity for the moment, the length of the total vector is relatively unchanged through the year, only the apparent angle is changing. It's easy to visualize how during the solstices the vector is almost parallel to the ecliptic, so daylight hours during those months don't change much day to day. Since the whole vector is eastward at that time, the days are slightly longer, and the sundial noon is slightly and cumulatively delayed each day. It took me a while to realize that a curve of (mean noon-sundial noon) vs date is the integral of the above daily factors. So, maximal downward slope is during the solstices, and maximal upward slope during the equinoxes, with a bimodal curve through the year. Although I acknowledge it's hard to make a snappy video, his explanation didn't seem to hit the mark for explanation of obliquity at all....
Awesome presentation! I really enjoyed! I wish you would focus a bit more on the earth's tilt and how it affects solar noon time, and give a few more angles. You can see that it takes longer to complete its orbit when it's tilted, but I don't fully grasp it.
I think you mean rotation rather than orbit, and it's not that it takes longer to rotate, it's that it has to rotate further in order to make up for the Earth's revolution around the sun. And I don't understand that part of the explanation at ALL. They make it look as if the Earth's tilt disappears at the equinox-as if the poles pointed vertically with respect to earth's orbit at the equinoxes. Of course, this isn't true. The tilt points in the same direction at all times, which is why the North Star doesn't move through the sky throughout the year-the North Pole of Earth's axis is pointed directly at the North Star. The widths between lines of longitude are unchanging at any given point on Earth. The widths of the longitude slices that face *directly* at the sun do indeed change as the point at which the sun is directly overhead migrates from the Tropic of Capricorn to the Equator to the Tropic of Cancer, back to the Equator, etc. But why should we use the slices of longitude pointing directly at the sun? Why not a slice of longitude at any other latitude on Earth? No explanation is given.
+samramdebest Since at some points in the Earth's orbit, the Earth is closer to the Sun than at other points, the Earth would have to rotate slightly more for the Sun to come into view.
+samramdebest 1. Imagine you have an angle of 5° 2. Ask: What if you stay very close? 3. Ask: What if you stay ver very far away? -> The diameter (in very far away) is bigger.
Move ipad almost to your face. Now in order to see edges you need to turn your head left and right. If you move ipad further away that motion decreases by a certain angle to the point where you see the whole thing
Cant get over these animations ! (anyone know how he made them?) the difference between this and his first ever vid is astounding! Really well done henry!
Okay, all these crazy orbital and precessional effects governing the deceptively simple rotation and revolution of the Earth are really getting to my head. If you could make a video that explains all of these effects...that'd be great! :D
I understand everything except the part about narrower slices of longitude being aimed at the sun. When the Earth is tilted away from the sun in December, wouldn't longer slices of longitude be aimed at the sun?
+tennisdude52278 I found the wording about "narrower slices" confusing as well. I have really struggled with this part of the video. I think I have some understanding now after considering the earth as a cylinder spinning around its axis. I think the fact that the earth is a sphere (roughly) makes it even harder to visualize. Get some 3-D cylinder like a oatmeal container and try spinning it while moving it around an imaginary sun. Keep the axis of the cylinder constant and you can verify that it does have to spin more for a line parallel to the axis on the cylinder surface to point to the sun. It doesn't matter if one is on the North or South of the cylinder, just as it doesn't matter if one is on the N or S of the earth.
King George Dental I get that the Earth's revolution makes the day longer. But what I don't get is how the Earth being tilted towards or away from the sun makes the day longer than 24 hours.
+tennisdude52278 I think I got it. Imagine the most extreme case, where the North and South pole of the Earth are faced sideways, like a soup can on its side. Imagine the Earth is facing the same direction regardless of its orientation about the sun. Assume that the orbit of the Earth around the sun is very slow compared to the rate at which the Earth rotates, so that at any point in the Earth's orbit, you can imagine as the Earth staying still with respect to the sun and simply rotating in place. At two points in the Earth's orbit, the North or South pole is approximately facing the Sun. No matter how much the Earth rotates during that period of time, the amount of sunlight does not change on each part of the earth. At another two points in the Earth's orbit, the Earth's rotation rotates perfectly away from the sun, and the length of the day is simply equal to the time it takes for the Earth to rotate 360 degrees. Since the Earth is neither perfectly upright nor perfectly flat on its side, it stands to reason that the length of days throughout the year is somewhere in between these two extremes.
***** Thank you for trying but this explanation doesn't make any sense to me. I followed your up until the start of the second paragraph. As the earth rotates the north pole which is now facing the sun would begin to turn away. Yet you say the amount of sunlight doesn't change.
tennisdude52278 Imagine the Earth was a rotisserie chicken and the stick came in through the south pole and out through the north pole. That is the direction that the Earth is supposed to be rotating.
Hier00 I believe he's showing the earth" upside down" with the South Pole facing the sun as he did in his earlier pictures where you could clearly see the tip of South America facing upward.
I see a bunch of people confused. Let me simplify. December has the shortest "DAY" as in "daylight" portion of the day, but the actual "6am to 6am" time is marginally longer due to what can be chalked up to rounding errors in our approximations. So longest "full day" despite shortest "day light"
+S.kayla tron Well vsauce shed some interesting light on that topic. It is possible, but that would mean that closer to the equator, buildings would need to be sloped more and more. so its NOT true, but it isn't an impossible concept
Derek Furst I remember seeing that one, but its very highly unlikely that a flat planet to ever exist knowing what we know about how planets are formed.
+Derek Furst The impossibility lies in the fact that they believe the earth accelerates upwards at ~9.81m/s/s, which would mean the earth would reach the speed of light.
I live in the northern part of Norway well within the arctic circle and during winter we get increasingly shorter periods of daylight every day up until the sun will be completely behind the horizon 24/7. We call this "the dark period" where there'll be twilight or just really dark almost all day. So we don't really say that December has the longest days but rather that winter (which does include December) has the shortest days and longest nights. But during summer however, we get something else that is also unique to this region, and that is the "midnight sun" where the sun stays above the horizon and you have daylight all day. :)
Nice video. Just one thing: This video did not take into account another factor: The earth is spinning faster in Winter, because most of its trees are in the northern hemisphere. When they drop leaves, they increase the spinning of Earth around its axis, as angular momentum is conserved. Still a nice video! Question: This actually should cause secondary lateral forces (however tiny), which could also explain (or not) the Nutation of our home planet. I am lazy to do the math, feel free to check out this hypothesis. Further question: Due to the movement of the continents over the eons and climate changes, this means that the thing constantly changed. How would a Pangea model look like?
Milankovitch actually made his own calendar which is officially the most precise calendar ever made. Some Orthodox churches use it (that's why some Orthodoxian churches celebrate Christmas on 25th December instead of 7th January)
Here are my short summaries: Tilt changes day length. Tilt means the rotation is an oval in the orbital plane. Thus when oval has long edge to the Sun it covers the exta 1 degree fast. Pointy end to the Sun its slow for extra 1°. Orbit changes day length. Oval orbit so when Earth is faster more than 1° extra to make up, when Earth slower there is less than 1° extra to make up.
June 21 and December 21 are the approximate dates for the first days of the summer and winter solstices respective. January 3 is the approximate date in which Earth is at its perihelion at about 0.983 astronomical units (AU) or 147,098,070 kilometers (km). July 4 is the approximate date in which Earth is at its perihelion at about 1.017 AU or 152,141,035 km. The orbit of Earth does fluctuate as it has the Moon which slightly alters its trajectory in addition to causing ocean tides.
1:10 "More rotation takes more time", but the earth is also moving faster! So is it really clear that the day should be longer, or a hidden computation is necessary to analyze this trade-off?
I'm from northern Scotland and this time of year we get about 4 hours of daylight and the rest of the time its pitch black. Street lamps come on at about 3pm.
I live in the southern hemisphere (39ºS). it is january. We've got ligth from 5:30 until 23:00. Its quite nice. Oh, and at 1:08, you may have meant "accurate" instead of "precise" (;
This is the way it is because they say so. Even though they can't physically prove it with cameras. They do a real good job with cartoons and paintings and cgi.
SO HAPPY our calendars and clocks don't rely on earth's orbit and rotation anymore. People would have to memorize so many technicalities like this just to know what time of day it is.
According to Phil Plait on Crashcourse Astronomy #13, things gets weird on planet Mercury. Considering Mercury's orbit is highly eccentric plus a peculiar tidal locking ratio of 2:3, i.e. 1.5 mercury day=1 mercury year, when at perihelion the orbiting angle velocity exceeds the revolutionary angle velocity. That is: On Mercury, at times, the sun appears to go BACKWARDS.
I simply do not understand the second day-lengthening effect. Yes I can see that "narrower slices of longitude are facing the sun", when the tilt is facing the sun, but to me the important thing is the degrees, which dont change. Same thing as 90 degress of a circle is spanning much less the closer you get to the center, but it's none the less the same number of degrees. Any nice explanations, references or useful way of looking at this? Much appreciated.
Stop at 1:21 when the earth is to the left. Look at the distance between two longitudes at the right outer side of earth next to the white background - it's big. Now look at 1:24 and compare the distance between two longitudes facing the sun next to the white background - it's smaller (and at 1:24 you can also see the "dark side" which would be the side that was facing the sun in 1:21, so you can even nicely compare in one picture). So using this top down/bottom up view helps understanding this. EDIT: Hmmmm, the more I think about is the more of a problem I have. I guess your argument is, that it takes 24h (for the sake of simplicity) to rotate earth 360°. So it has a constant angular velocity (°/s). So the 0° longitude line rotates every 24h until it's at the same place again. And how would the 1:24 pic look from a top-view? I also had problems with this second phenomenon, then I thought I understood it, then I thought more about it and now I do no longer understand it.
@@whuzzzup thanks! But all this is about degrees, but even tough the slice is smaller, it still covers the same number of degrees. Hmm I'll try and see if I get it :D
And, since we're closer to the Sun in winter, a second in winter is a itty bitty bit longer than in summer, because the closer you are to a massive object, the slower time is for you. We don't EXPERIENCE this because we are in the Earth, and time isn't distorted at all to us. It is so little of a difference, we don't even bother to measure it. For more insight on this, read Icarus at the Edge of Time. It's a good book.
Can anyone explain 1:27? Where he said narrower slices of longitude are pointed directly at the sun. Surely it is *longer* slices. Please correct me if i'm wrong.
Fantastic animations Henry.
I FOUND DESTIN :DDDDD
+Kakunapod can we start a new game like wheres waldo only with destin and its the entire internet?
+Donal O'Shea Not very hard, just look on some of minutephysics' videos lol
+Donal O'Shea If he gets to the deep web, we're screwed...
yup
Just thinking of all the research that went into this video is stressing me out
it's also a vsauce video
This channel minute Physics used Wikipedia it says so in the Description.
So Minute Physics didn't have to do as much reasearch as you think. Now the Guys at Wikipedia definitely did.
I always think I'm already going to know what these videos are about, but every single time I end up having my mind blown...
Exactly bro it took me a while to be able to admit I can never have learned everything , and definitely not at 20 years old lol
me too
I always wondered why the sunrise and sunset times weren't symmetrical. Thanks for explaining it.
-Milankovich-
-Milankovitch-
Milanković
+velikiradojica There's a great movie out there called Being John Milankovic
+Jonathan Stewart wasn't it "being john Malkovich?"
+Enrico Sylvester *woosh*
+velikiradojica Миланкович
Enrico Sylvester This one's better. It follows John Milankovic around through all his cycles.
This is really just a fault in the English language. In Danish, we have the word "døgn" which means a full day and night or 24 hours, whereas in English only a day is used which can either mean the time where the sun is up or a full cycle of day and night aka 24 hours.
Most people say that winter has the shortest day of the year because they mean day as in the time the sun is up, whereas you are talking about a day meaning 24 hours.
In conclusion, winter has both the shortest and the longest days at the same time. Hurray for English.
+Vaxivop Dygn in swedish.
+Vaxivop english and many other languages really. It's the same in portuguese
+Vaxivop But then we can say things like " the shortest day is also the longest" :D which is quite amusing.
now that I think about it, yeah! Polish also has that, 24 hours is "doba".
I speak Russian and imo English has a real lack of a word to describe one 24-hour cycle. In Russian there's день (den' -day) and сутки (sutki - from midnight to midnight). I take it there's no such word in any germanic language?
3000 years of observations in 3 minutes :D
That, at the same time, the frustration that comes with gathering knowledge as well as the core reason why we're able to gather knowledge at all: figuring stuff out is always harder and more time consuming than comprehension of what others have figured out.
this video wasnt supported? :OO
+Sami Küçükata, there is a link to the list of Patreon supporters in the video description.
Hhe. My point of saying this was, my brain is so used to hear "this video was supported by..." so when i didnt hear it, i was like 'whaat' ( ･ัω･ั )
oh yes wasn't it supported
+Sami Küçükata And it's more interesting than a lot of those commercially supported videos.
+Barış Savar oha kürt
Mind blown! I’ve been wondering why the sunrise and sunset turn around at different months. I’m still not sure I grasp it, but I get the general impression of what you’re saying anyway! Thanks for that!
I laughed tears at "REALLY not to scale". :D
I wanted to check what day was the longest, but I could only find articles about the sun solstice. Then I remembered that there was a minutephysics video about it.
Thanks, Henry!
Look up equation of time
I dont care how long the day is, if I have to go to work in the dark and come home in the dark it will still depress the shit out of me.
+Azivegu What time do you leave?
8 in the morning
Azivegu Lol, for me it gets bright at 6 and dark at 6. But there are too many trees near my house and thanks to them its cold as fuck even in the afternoon
Shayan
better than a friend of mine in finland. For him the sun comes up at around 11 and goes down at 3
This annoys the fuck out of me too! Leaving at 6am and home at half 5 😴
This video does not explain why I woke up 4 hours early today.
+BlueBetaPro 4 hours? you're lucky, I woke up sometime before 1:30.
+ijfharvey Who says he doesn't usually wake up at 5? :)
+BlueBetaPro lol i work up abnormally early too
me too. _.
+BlueBetaPro Aliens.
1:18 The explanation used here for describing the role of the obliquity of the ecliptic in determining the length of day is practically incomprehensible.
Here is a more intuitive explanation: 1. For observers on the Earth, the Sun appears to move eastward along a path relative to the background stars called the ecliptic; this path is due to the Earth's orbit around the Sun. 2. The Sun appears to move eastward along this path, partially counteracting the Sun's apparent westward motion due to the Earth's rotation and making the day take longer. 3. At noon during the solstices, the Sun appears to move exactly eastward along the ecliptic, maximally counteracting the westward motion and making the day take the longest. 4. At any other time of year, the Sun's motion along the ecliptic is not only eastward, but slightly diagonally up or down in the sky as well. 5. This up-down motion means that there is less eastward motion available to take away from the westward motion of the Sun. 6. During the equinoxes, the ecliptic is the most tilted at noon compared to any other time of the year, which means that there is the least amount of eastward motion available to counteract the westward motion of the Sun, making the the day the shortest.
Viewed from the Sun: during the solstices, the rotational movement of the sunlit portions of Earth is antiparallel to the orbital motion of the Earth, while at any other time of year, the motion is at an angle and counteracts the orbital movement less.
+BirdValiant Yes, you've explained the obliquity effect about as well as I can imagine. Although it would be nice to avoid it, I keep coming back to the perspective where the observer is on Earth, seeing the apparent movement of the Sun against a background of stars. A daily snapshot of the Sun at the same time each day reveals a vector shift by about a degree every day along the ecliptic. That daily relative velocity vector can be split into two components at right angles to each other. The vertical component, parallel to longitude, results in daily, cumulative creep of the Sun north or south, causing a change in daylight hours. The latitude component results in eastward creep and change of season. If one ignores eccentricity for the moment, the length of the total vector is relatively unchanged through the year, only the apparent angle is changing. It's easy to visualize how during the solstices the vector is almost parallel to the ecliptic, so daylight hours during those months don't change much day to day. Since the whole vector is eastward at that time, the days are slightly longer, and the sundial noon is slightly and cumulatively delayed each day. It took me a while to realize that a curve of (mean noon-sundial noon) vs date is the integral of the above daily factors. So, maximal downward slope is during the solstices, and maximal upward slope during the equinoxes, with a bimodal curve through the year. Although I acknowledge it's hard to make a snappy video, his explanation didn't seem to hit the mark for explanation of obliquity at all....
Yeah its kind of absurd how much he decides to squeeze into such short videos
Thank you very much it was indeed confusing (eventhough you probably dont even remember having written this comment by now)
Ok ok ok...... say that one more time
I'm like "huh, December 22th, it must be close".
And a few seconds later "omg it's today!"
December 22... my birthday... the longest day of my life... hey... I made a joke... Actually I'm just crying behind my computer right now.
+Broekmanium Don't cry, the Steam sale starts today.
Happy birthday?
+Broekmanium Happy birthday.. to us.. lol
Michael The Awesome! You my friend now?
Isaac Als Yayyy
This is explains why that time between summer break and fall break feels shorter than that time between winter break and spring break.
wow i never really thought about that, thats amazing :D
Awesome presentation! I really enjoyed! I wish you would focus a bit more on the earth's tilt and how it affects solar noon time, and give a few more angles. You can see that it takes longer to complete its orbit when it's tilted, but I don't fully grasp it.
I think you mean rotation rather than orbit, and it's not that it takes longer to rotate, it's that it has to rotate further in order to make up for the Earth's revolution around the sun. And I don't understand that part of the explanation at ALL. They make it look as if the Earth's tilt disappears at the equinox-as if the poles pointed vertically with respect to earth's orbit at the equinoxes. Of course, this isn't true. The tilt points in the same direction at all times, which is why the North Star doesn't move through the sky throughout the year-the North Pole of Earth's axis is pointed directly at the North Star.
The widths between lines of longitude are unchanging at any given point on Earth. The widths of the longitude slices that face *directly* at the sun do indeed change as the point at which the sun is directly overhead migrates from the Tropic of Capricorn to the Equator to the Tropic of Cancer, back to the Equator, etc. But why should we use the slices of longitude pointing directly at the sun? Why not a slice of longitude at any other latitude on Earth? No explanation is given.
To be honest ill need a lot more time than a 3 minute video to thoroughly grab this one.
And I'm suddenly hooked on this channel and can't be released. But I like it. I'm subscribing for sure after this video!
Around 8 hours of sunlight here in London :(
London dosen't get sunlight, your options are overcast, fog or rain.
+TheyCallMeGawd Get your facts right. That's Seattle.
+darksoulzFZ i fel sik... i cnt spel
+FreakinYAY
Also where i live.
A whole month of sunlight here in Antarctica :)
Your videos are great and really helped me feel happy after a bad day. Thank you!
I don't understand 1:25
+samramdebest Since at some points in the Earth's orbit, the Earth is closer to the Sun than at other points, the Earth would have to rotate slightly more for the Sun to come into view.
+bacon That's not what he says at 1:25
+samramdebest 1. Imagine you have an angle of 5° 2. Ask: What if you stay very close? 3. Ask: What if you stay ver very far away? -> The diameter (in very far away) is bigger.
Move ipad almost to your face. Now in order to see edges you need to turn your head left and right. If you move ipad further away that motion decreases by a certain angle to the point where you see the whole thing
+Andrey Cherneha Genious!
Thank you for the video, MinutePhysics. I enjoyed it and learned a lot.
THAT'S TODAY, BOYS.
+Leo Whoa you can read calendars too?
TheBluMeeny You're not suppose to type that on the internet... The government will do cruel experiments on your superpowers now.
+TheBluMeeny Ouch.
Leo We can run away together though. I heard of a group that can do what we can too.
They're called the.... C-men. ;)
You said that when it was midnight in Australia.
Cant get over these animations ! (anyone know how he made them?) the difference between this and his first ever vid is astounding! Really well done henry!
Shouldn't this be on MinuteEarth? Either way, great video.
I love these videos about concepts that everyone thinks they know but seldom really understand.
Mind = blown :)
Always manage to blow me away MP. Well done
I like to pretend I understand these
beinyourguard, ditto
#metoo
stoat2 You've been assaulted?
I would love to see an explanation of particle spin. Please.
Great video
Okay, all these crazy orbital and precessional effects governing the deceptively simple rotation and revolution of the Earth are really getting to my head. If you could make a video that explains all of these effects...that'd be great! :D
I understand everything except the part about narrower slices of longitude being aimed at the sun. When the Earth is tilted away from the sun in December, wouldn't longer slices of longitude be aimed at the sun?
+tennisdude52278 I found the wording about "narrower slices" confusing as well. I have really struggled with this part of the video. I think I have some understanding now after considering the earth as a cylinder spinning around its axis. I think the fact that the earth is a sphere (roughly) makes it even harder to visualize. Get some 3-D cylinder like a oatmeal container and try spinning it while moving it around an imaginary sun. Keep the axis of the cylinder constant and you can verify that it does have to spin more for a line parallel to the axis on the cylinder surface to point to the sun. It doesn't matter if one is on the North or South of the cylinder, just as it doesn't matter if one is on the N or S of the earth.
King George Dental
I get that the Earth's revolution makes the day longer. But what I don't get is how the Earth being tilted towards or away from the sun makes the day longer than 24 hours.
+tennisdude52278 I think I got it. Imagine the most extreme case, where the North and South pole of the Earth are faced sideways, like a soup can on its side. Imagine the Earth is facing the same direction regardless of its orientation about the sun. Assume that the orbit of the Earth around the sun is very slow compared to the rate at which the Earth rotates, so that at any point in the Earth's orbit, you can imagine as the Earth staying still with respect to the sun and simply rotating in place.
At two points in the Earth's orbit, the North or South pole is approximately facing the Sun. No matter how much the Earth rotates during that period of time, the amount of sunlight does not change on each part of the earth. At another two points in the Earth's orbit, the Earth's rotation rotates perfectly away from the sun, and the length of the day is simply equal to the time it takes for the Earth to rotate 360 degrees.
Since the Earth is neither perfectly upright nor perfectly flat on its side, it stands to reason that the length of days throughout the year is somewhere in between these two extremes.
*****
Thank you for trying but this explanation doesn't make any sense to me. I followed your up until the start of the second paragraph. As the earth rotates the north pole which is now facing the sun would begin to turn away. Yet you say the amount of sunlight doesn't change.
tennisdude52278
Imagine the Earth was a rotisserie chicken and the stick came in through the south pole and out through the north pole. That is the direction that the Earth is supposed to be rotating.
I subbed to you a loooong time ago and this is the first video that appeared on my youtube feed.
1:58 Is the image on the right not accurate? The tilt should be the other way, right?
Hier00 I believe he's showing the earth" upside down" with the South Pole facing the sun as he did in his earlier pictures where you could clearly see the tip of South America facing upward.
And the days are shorter in the Northern hemisphere in Dec.
I see a bunch of people confused. Let me simplify. December has the shortest "DAY" as in "daylight" portion of the day, but the actual "6am to 6am" time is marginally longer due to what can be chalked up to rounding errors in our approximations. So longest "full day" despite shortest "day light"
Took me a really long time to realize that today was dec 22
+Max Jiang shh bby is ok
+Max Jiang Happy Winter Solstice late greetings. Another rotation around the sun without crashing into a huge asteroid.
how ironic if it was about 30 seconds
It took me 5 seconds to realize your comment was 11 months ago
Dude, you make my life better. I enjoy so much watching your videos. Thank you very much for your amazing work!!
Sitting on a constantly spinning ball makes me dizzy.
LOL - Henry, love the illumination at ~1:18 - 1:24. Superb! :)
my brain hurts ;/
you are just great. one of the best channels on youtube
I'd bet all the down votes are from flat earthers.
Yes, even today there are idiots that still believe the earth is flat.
And dear god, they're passionate about it too! How can anybody be so passionate about a concept that's so stupid?
+S.kayla tron Well vsauce shed some interesting light on that topic. It is possible, but that would mean that closer to the equator, buildings would need to be sloped more and more. so its NOT true, but it isn't an impossible concept
Derek Furst I remember seeing that one, but its very highly unlikely that a flat planet to ever exist knowing what we know about how planets are formed.
+Derek Furst The impossibility lies in the fact that they believe the earth accelerates upwards at ~9.81m/s/s, which would mean the earth would reach the speed of light.
Powpuppet Maybe thats why we get dizzy spells once in awhile. LOL
I live in the northern part of Norway well within the arctic circle and during winter we get increasingly shorter periods of daylight every day up until the sun will be completely behind the horizon 24/7. We call this "the dark period" where there'll be twilight or just really dark almost all day. So we don't really say that December has the longest days but rather that winter (which does include December) has the shortest days and longest nights. But during summer however, we get something else that is also unique to this region, and that is the "midnight sun" where the sun stays above the horizon and you have daylight all day. :)
the earth is flat
Seems legit
+xsabirx your head is flat
3Durka1 how is it a ball
Obvious troll is obvious
Caresser not even trolling
Nice video. Just one thing: This video did not take into account another factor: The earth is spinning faster in Winter, because most of its trees are in the northern hemisphere. When they drop leaves, they increase the spinning of Earth around its axis, as angular momentum is conserved. Still a nice video! Question: This actually should cause secondary lateral forces (however tiny), which could also explain (or not) the Nutation of our home planet. I am lazy to do the math, feel free to check out this hypothesis. Further question: Due to the movement of the continents over the eons and climate changes, this means that the thing constantly changed. How would a Pangea model look like?
Another reason why I love December. :D
Milankovitch actually made his own calendar which is officially the most precise calendar ever made. Some Orthodox churches use it (that's why some Orthodoxian churches celebrate Christmas on 25th December instead of 7th January)
from markers to graphics, good shit mate!
Here are my short summaries:
Tilt changes day length. Tilt means the rotation is an oval in the orbital plane. Thus when oval has long edge to the Sun it covers the exta 1 degree fast. Pointy end to the Sun its slow for extra 1°.
Orbit changes day length. Oval orbit so when Earth is faster more than 1° extra to make up, when Earth slower there is less than 1° extra to make up.
You really are smart, Henry. Thank you.
I always enjoy these videos man!
June 21 and December 21 are the approximate dates for the first days of the summer and winter solstices respective.
January 3 is the approximate date in which Earth is at its perihelion at about 0.983 astronomical units (AU) or 147,098,070 kilometers (km). July 4 is the approximate date in which Earth is at its perihelion at about 1.017 AU or 152,141,035 km. The orbit of Earth does fluctuate as it has the Moon which slightly alters its trajectory in addition to causing ocean tides.
I think I need to watch this a few times to make complete sense. Thanks.
1:10 "More rotation takes more time", but the earth is also moving faster!
So is it really clear that the day should be longer, or a hidden computation is necessary to analyze this trade-off?
Glad to live in the southern hemisphere! 🌞
Proud to be same nationality as Milutin Milanković.
Those were some of the best visuals so far
Beautiful. I've missed these videos.
2:16 If you follow any cultural calendar established before the standardization of hours and days, you probably already knew this.
I'm from northern Scotland and this time of year we get about 4 hours of daylight and the rest of the time its pitch black. Street lamps come on at about 3pm.
Awesome. Thank you for clearing that up.
I live in the southern hemisphere (39ºS). it is january. We've got ligth from 5:30 until 23:00. Its quite nice.
Oh, and at 1:08, you may have meant "accurate" instead of "precise" (;
This is the way it is because they say so. Even though they can't physically prove it with cameras. They do a real good job with cartoons and paintings and cgi.
Great, you blew my mind again.
You typed credits for music twice in the description... ;)
Anyway, the video was excellent as always...
Oh man this is so cool! Thanks for the video!
SO HAPPY our calendars and clocks don't rely on earth's orbit and rotation anymore. People would have to memorize so many technicalities like this just to know what time of day it is.
Awesome explanation
Wow, I was able to watch an episode of Minute Physics without being assaulted by advertisements at the end. Refreshing.
MinutePhysucs, outstanding video, exceptionelly well-mande and highly-interesting!
thank you so much!!! the best presentation of this question ever~~~~ luv u guys!!
Remember the time when MinutePhysics videos where actually a minute long? Pepperidge farm remembers.
you my friend have earned a new subscriber! Cool stuff
wayyyy cool. i'd never would have known that. Thanks minute physics
That's so counterintuitive and annoying that I can't help but be impressed that people bothered sorting it out.
Thanks Henry!!
Trying to watch this at 1 in the morning is like attempting to teach a first grader long division
Wow, this must have been very hard to animate! Great job! :)
henry
you blew my mind away
amazing explanation
This explains why solstice actually happens during a period of days.
Good video, Henry! I'll recommend this one to my friends :)
wow.. most of that was in one ear and out the other.. thankfully this is youtube and I can watch it again
i didn't understand half of that....but i was certainly informed and entertained throughout! :D
great job as always keep up the good work :D i liked the animation !
I take that back. December 24th 2017, here I come!
According to Phil Plait on Crashcourse Astronomy #13, things gets weird on planet Mercury.
Considering Mercury's orbit is highly eccentric plus a peculiar tidal locking ratio of 2:3, i.e. 1.5 mercury day=1 mercury year, when at perihelion the orbiting angle velocity exceeds the revolutionary angle velocity.
That is: On Mercury, at times, the sun appears to go BACKWARDS.
Good. Carry on.
If you dropped somthing in a vacuum and and it never stopped falling would it ever reach terminal velocity, how fast would it go?
Oh man, it;s so refreshing to not see any support ad at the end of the video! What happened?
I simply do not understand the second day-lengthening effect. Yes I can see that "narrower slices of longitude are facing the sun", when the tilt is facing the sun, but to me the important thing is the degrees, which dont change. Same thing as 90 degress of a circle is spanning much less the closer you get to the center, but it's none the less the same number of degrees.
Any nice explanations, references or useful way of looking at this?
Much appreciated.
Stop at 1:21 when the earth is to the left. Look at the distance between two longitudes at the right outer side of earth next to the white background - it's big. Now look at 1:24 and compare the distance between two longitudes facing the sun next to the white background - it's smaller (and at 1:24 you can also see the "dark side" which would be the side that was facing the sun in 1:21, so you can even nicely compare in one picture).
So using this top down/bottom up view helps understanding this.
EDIT: Hmmmm, the more I think about is the more of a problem I have. I guess your argument is, that it takes 24h (for the sake of simplicity) to rotate earth 360°. So it has a constant angular velocity (°/s). So the 0° longitude line rotates every 24h until it's at the same place again.
And how would the 1:24 pic look from a top-view?
I also had problems with this second phenomenon, then I thought I understood it, then I thought more about it and now I do no longer understand it.
@@whuzzzup thanks!
But all this is about degrees, but even tough the slice is smaller, it still covers the same number of degrees.
Hmm I'll try and see if I get it :D
And, since we're closer to the Sun in winter, a second in winter is a itty bitty bit longer than in summer, because the closer you are to a massive object, the slower time is for you. We don't EXPERIENCE this because we are in the Earth, and time isn't distorted at all to us. It is so little of a difference, we don't even bother to measure it. For more insight on this, read Icarus at the Edge of Time. It's a good book.
Can anyone explain 1:27? Where he said narrower slices of longitude are pointed directly at the sun. Surely it is *longer* slices. Please correct me if i'm wrong.
Great topic and awesome animation work!
we love physics at cgs but your videos are great