How earth's tilt causes seasons | Cosmology & Astronomy | Khan Academy

How being Earth's tilt causes seasons. Created by Sal Khan.

Cosmology & Astronomy on Khan Academy: The Earth is huge, but it is tiny compared to the Sun (which is super huge). But the Sun is tiny compared to the solar system which is tiny compared to the distance to the next star. Oh, did we mention that there are over 100 billion stars in our galaxy (which is about 100,000 light years in diameter) which is one of hundreds of billions of galaxies in just the observable universe (which might be infinite for all we know). Don't feel small. We find it liberating. Your everyday human stresses are nothing compared to this enormity that we are a part of. Enjoy the fact that we get to be part of this vastness!

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[thegrandfoundationchurchof]

Thank God for Khan Academy. It is about time to bring back free education!
Our founding fathers wanted everyone to be educated. This is one of the main reason to live. We educated our selves since the day we are born. It is a never stopping thing we do. It is so fun! I really enjoy listen to Khan Academy.

[totyffanie]

This!! 🙌🏽😭 I have a test on Thursday, and all the professor does is read off his slides and elaborate barely. But here you explain everything. I so get it now! I wish you were my college professor! Thank you!

[PHZadeW]

Because he's a clever teacher, ha ha. As it's a common psychological teaching method to repeat sentences, so that they stick in the students mind. Advertising and music often uses some of these techniques in order to keep their product or song in the mind of the consumer. Have a good day! :)

[saadahmad]

Thank you sir for auch a great explanation!
I'm 20 and I'm wondering where I would have been today if I got such a great teacher throughout these years🙏

[gonzaloayalaibarre]

"This is the sun right over here, this is the sun, that is the sun..."

Urge to shout "Praise the sun!" intensifying.

[PorschaLaMaria]

I needed you as a professor back in college 👌🏼👌🏼

[hopegrungist]

Dude I just watch these for fun honestly. So one day I can go "we have seasons because of the tilt of the earth" for like no other reason than making me feel like a smart person :P

[ardynites]

It solidifies it more in your head, and it gives him time do draw his pictures.

[FollowHorus]

Khan - you have such beautiful voice! You were born to do this! Thank you for making learning joyful for all of us.

[Jiiiimmmmy]

It is due to the tilt again. In summer the sun is directly over-head, sun rays are falling pretty much perpendicular onto the earth surface. In winter this angle is sharper, the rays have to travel farther through the atmosphere (more adsorption and scattering etc.) for one thing. Also if you draw a diagram of earth and the sun, one with perpendicular and another with a sharper angle of insolation you will see that less energy falls onto a given surface area with a sharper angle of insolation.

[AccioVoldy]

From your previous video you said:
Currently, Aphelion = Northern Hemisphere summer and Perihelion = N. Hemisphere winter

Does that mean since summer in the northern hemisphere is occuring when the Earth is further from the Sun. Does that mean northern hemisphere summers are not as hot as southern hemisphere summers because of the 3% eccentricity in the orbit?

Thanks :D

[gregorysoutherland]

im so surprised that a flat earther hasn't come on to the comment section of this video and started ranting on "its a conspiracy" or "the government is feeding you lies or some crap"

[shansk]

Mr Khan,
I was watching the this video about earth's tilt causing the seasons. It certainly explains why the duration of night time and day time during summer and winter is different (the reason being axis of rotation is tilted) But, I did not understand one thing. All points on earth except the pole (south or north) points get sunlight at least for some time in a 24 hr cycle but the temperature (light energy) during those times are different in different season. For example, consider NYC.

[deniseshircliffjett]

I teach public education, and I love you Khan.  When I can't explain it, I know you can!  You back me up and I use your videos to re-enforce my own understanding.

[KarlBonner]

I don't like the whole bit about the atmosphere absorbing more of the winter sun. Yes it is true especially for UV rays, but the real reason a low sun angle leads to less heating is that the same amount of energy gets spread out over a larger surface area when it hits the ground. The effect of a thicker diagonal column of air absorbing more energy doesn't explain seasonal variations!

[MeisterDonDon]

Thank you for this very interesting video. I really enjoy that not only do you make videos on school subjects but also things like these which answer questions about everyday life. It's nice to have videos like these which can make people appreciate how complicated something like seasons actually are and making people less ignorant of the things around them.

[RiyadhElalami]

That is amazing, that is science.
It was a bit of confusing at the beginning but I understand it well thanks Sal.
I hope I will be half of what you are in the future

[KatiaTRH]

This is a great explanation. The only problem i had was that he kept saying "...tilted away from the earth..." when he should have said "..tilted away from the sun...". Anyways, i saw past that and i got the concept so thanks much.

[Handlez]

It may be facing the sun, but Summer and Winter in New York occur during different periods in the earths orbit. So although both are facing the sun in Winter NYC is tilted away from the sun resulting in less energy.

[pujasaroj]

Explain how the tilt of the Earth's axis and the revolution cause variation in the length of day and night

Pls ans this question....