History of Astronomy Part 1: The Celestial Sphere and Early Observations
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- Опубликовано: 16 июл 2024
- Now that we've learned about how the universe began, as well as the development of the Milky Way galaxy, the solar system, and the Earth, it's time to learn about the human beings that came to inhabit the Earth. Eventually, they began to look at the sky and wonder about what they were seeing, which initiated a journey of discovery that has brought us to the knowledge we have today, and have been discussing throughout this playlist! How did our ancestors figure out all this stuff? Let's go through the major breakthroughs over the next few tutorials!
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I'm happy to see your subscriber count continuously increasing, you really deserve it. I've learned a ton from your videos, and I especially appreciate the self-awareness of how you articulate specific concepts. You have a very clear understanding of what it means to not already understand something, and you tap into that very well. The fact that you include opposing arguments while explaining things is just perfect.
Thanks!
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This is exactly what I was looking for! Not too dumbed down, but not too complex. Thank you!
Fantastic graphics! I've been looking for videos for my classroom, and not only are you terrific at explaining things, but you go at a nice pace. Great job!
hello
My daughter and her school is doing the Science Olympiad and I am on the Reach for the Stars as a Mentor......Thank you for your tutorials to help a layman who has only seen or understood this from a very high level, learn the weed stuff to help our team.....You make it easy for the average guy to see the obvious. I have now subscribed to your channel!
i love the subtle "see flat earthers ur fucking wrong" every time he explains something
This episode was very well done. Looking forward to the next in the series.
This guy is great. Never had i imagined I'd understand basic astronomy like this.
1:15 Ancestors
- Constellations
- Sun, Moon, Planets
2:52 The Geocentric Model
3:47 The Day "Sunrise, Sunset"
The Month "Moon's Cycle"
The 4 Seasons, The (Earth) Year = 1 (Earth) Revolution around the Sun
5:00 The North Star
5:45 Constellations mark passing of time. They appear and disappear in cycles
6:54 How do we have seasons?
The (23.5 degree) Tilt in Earth's Rotation and The Sun
8:23 Equinoxes and Solstices
8:58 Stonehenge
9:40 The Moon ((1) New Moon, Waxing Crescent, , Waxing Half, Waxing Gibbous, Full, waning Gibbous, Waning Half, Waning Crescent, New Moon)
thats so legendary
You links make this into numerous mini lectures! Such a good idea!
@@alphamarquis6325 oooo
aa
I have to admit I thought moon phases were related to shadows but i never quite knew why. Thanks for the correction! I'm happy to say I've never thought aliens visited the earth and piled up rocks.
I rarely leave comments - but I gotta say you did a great job with this series.
The word "planet" comes from the Greek "planetes," which means "wanderer." This is because they moved independently of the stars, so they wandered about the night sky. I find this fascinating.
Thanks!
I've been working on a fictional world for D&D, and resources like yours are very helpful! Thanks!
Professors are human beings? When did this happen? 😁😁😁
A fantastic explanation.
Thank you Dave! This was something I never had the imagination to understand. Until now.
I find the ancient history of various scientific & mathematical subjects super fascinating. I will watch every video you make on the ancient history of science!
(I especially love the videos about peoples who had incomplete knowledge and/or got stuff wrong, like the history of drugs.)
Thank you for such fantastic explanation
Very nicely explained BUT there is a major issue at 5:30. Non moving star at celestial North Pole was not seen by ancient ancestors for most of the time - except for some short time between 3800 BCE and 2200 BCE when Thuban was close enough to be perceived as non moving and 1200 CE to now when the Polestar was close enough to be non moving. It will be closet to celestial North Pole around 2100 CE and slowly drift away.
Celestial sphere? More like “I’m really glad Professor Dave is here!”
With just enough observation we can end our ignorance and this is why science and it's methods are the thing enlightens humans the most. Not saying "it is because of the invisable gods" and actually look for a patern
Superb content sir :)
This was interesting nice work!
The most clear video I have ever seen
Thanks a lot 💜💜💜
Three classes now. three separate classes have had me watch this guys vids.
Those are three respectable teachers
Great content.
Great video, though I don't know if I'd say the lunar phases have _nothing_ to do with shadows; just not the shadow of another object (which is what I think you meant). It's undeniable that the dark portion of the moon is dark because it's shaded from the sun, but it is in fact the *moon itself* which provides that shade.
Easy to understand 👍👍
love your videos. One of my favourite teachers.
Is there any way to obtain your videos without the intro or must i do some editing myself (no problem just wondering)
looking to create some playlists and videos for my friends and my daughter :)
Well-Done
your videos are very good
Your videos are so interesting
7:18 I have been wrong for over 20 years. Thanks.
When i first was explained the seasons, i didn't understand that the tilt caused the seasons and though the orbit of the earth, wich i once saw wasn't an actual circle, was causing the seasons by getting further away and closer.
Great video but tiny wee correction - Stonehenge is in Wiltshire not Wilshire
let's go dude!
I honestly enjoy your content. Keep it up :)
GREAT 👍
Sun moon planet rise setting
I subscribed to this channel only because of that opening song.
Hi professor Dave.
Good job sir
Let's go dave
Good
At the 2:44 mark of clip (4 stars in our solar system described using roman deities) you seem to skip by with out an explanation explaining the deviation of labels applied with identifiable acknowledgement in comparison to the rest of the night sky. Visual aids identify identity of celestial bodies (shape &/or location) to characteristics or titles attributed to characters? I wonder if those 4 stars were the most prominent depending upon season? E.g. god of love possibly attributed to spring (many new born animals this time of year) but why IS THAT relatable to that particular planet? {I've forgot if it was mars or Venus because where i paused the vid 2:44 no longer shows what I was using while I typed this ) and the other closest planet in our solar system regarded in an opposite description 'god of war'? Love vs war? Or love & war?
I can understand why people of ancient imagination observed constellations and labeled them in unanimous visual agreement. However im confused with how they attributed the other planets in our solar system as 'gods' or 'characteristic reminiscent of character attributed too'? Did these planets shine greater during these seasons? Or what & why?
Cool
Check out the 80 hours of other content first! Lol. Jk love ya Dave
Hey
I don't understand how the zodiac signs were associated with the times when they were behind the sun because they couldn't be seen, how did this come to be?
LMAO @ 53 seconds. That's great!
10:49 the gods have a period
Lmaoooo
I wonder if I ever would've thought about what is the moon, why is the moon up there, etc. Or to reject the myths that said it was a goddess.
What is the difference between celestial equator and ecliptic ?
The celestial equator is a projection of earth’s equator, the ecliptic is the plane of the solar system.
@@ProfessorDaveExplains Ah, thanks. Now i understand the difference
Great 👍 e
there are seriously people out there that think the seasons are because the earth is closer or further from the sun? please tell me that was a joke
Eclipse based or Sun or Planets crossing These Signs ?
I suggest some research in Oriental Astronomy as well, because in the east, especially in the ancient Indian civilization, the concept of Earth being a spherical planet, the milky-way having billions of stars, and a heliocentric model of the solar system was accepted many thousands of years ago as a scientific fact.
Can somebody please explain, what does it mean that the planets move "slower" than the stars? (At 3:10 in video) I don't quite get it. Wouldn't they travel faster? In a space of a month for example, Jupiter will change it's position farther than the distant stars, no? I would love for somebody to correct me, I am very ignorant of astronomy, I'm trying to learn more about it. Thank you.
I think he’s referring in part to how long it takes for a planet to complete one cycle in the night sky, known as the synodic period, since Polaris would be an obvious counterexample if we took his statement at face value. All planets orbit the Sun in the same direction (counterclockwise from a Northern Hemisphere perspective). It would take the Earth more than one year to catch up with planets that are further from the Sun, since they have moved partway around the Sun by the time Earth returns to its original position, while stars are at back at their original positions. It’s more complicated for planets closer to the Sun than Earth is, since they don’t wander too far from the Sun in terms of angular distance, but they too have cycles that repeat. Let x be the length of a year of some planet in terms of Earth years. Then C(x) = x/|1-x| gives us how long it takes for the planet to complete a cycle in Earth’s sky (i.e., for Earth to catch up to it or vice-versa), also in terms of Earth years; and D(x) = x^(2/3) (derived from Kepler’s laws of planetary motion) tells us that planet’s average distance from the Sun in terms of the average Earth-Sun distance. Solving for C(x) = 1, we get that a planet with a year equal to 0.5 Earth years will take a full year to complete a cycle, which corresponds to an average distance from the Sun of D(0.5) = 0.63 astronomical units. Plugging in some other values for x (or using calculus), we see that any planet closer than this will actually complete a cycle in the sky more quickly than the stars, and anything further would take longer than the stars. Thus, Mercury is the only planet to complete a cycle more quickly than the stars, passing between Earth and the Sun every C(88/365.25) = 0.32 years, or 116 days, while Venus takes C(224.7/365.25) = 584 days! Earth passes Mars every C(687/365.25) = 780 days, Jupiter every C(4333/365.25) = 399 days, and a planet 100 times Earth’s distance from the Sun every C(x) = C(D(x)^(3/2))
= C(100^(3/2))
= C(1000)
= 365.6 days.
So the further out the planet, the more starlike it moves in the night sky.
@@jamescook9125 Thank you sir for this detailed explanation. I'm just a layman who likes astronomy, sometimes it's hard to find clear explanations. Did you study astronomy or do you just know a lot about the subject?
@@user-vm6lb3dz5w I just have an interest in a lot of things. You definitely don't have to be an astronomer to learn this stuff.
Best
If we were not in cosmo then we would be able to witness it’s collapse
That's better then my professor explains it
Blood red
❤❤❤❤❤❤❤
LOL This is really gona trigger flat earthers!!!!
This doesn't discuss ancient astronomy. How did they construct and physically use early observatories? How did they calibrate them, how did they make measurements?
There is so much to learn. This episode should be number 10 or 20 in the series. Not number one.
So I’m an astronomy student and currently member of the Nasa scholar stem program. What he’s doing is what my professor did our first week of class teach us about the celestial sphere so we have an understanding of how other astronomers look at our planet and solar system. Many instructors use the celestial sphere as a starting point in Astronomy.
10:23 are these images correct?
It’s correct as seen from the southern hemisphere if time goes backwards. The moon orbits the sun counter clockwise as seen from the north pole, but in the graphic it orbits backwards. But imagine 2 of the moon corresponds to number 2 as seen from the the southern hemisphere, where the moon looks upside down compared with the northern hemisphere.
So we can’t draw a graphic that shows the correct image of the moon for every observer at the same time. This is just a simplified illustration of the principle.
Ok
Ok
We are in cosmo’s micro verse
2nd comment
First reply to your comment!!!
Did our ancestors know the planets were planets and not just stars? Did they have any clue the difference?
The only difference they could see between the planets and the stars, was that if they looked to the sky every night, they'd notice certain stars would move independent of the others, and so they called them planets. If you look to planets with the naked eye, you'd hardly tell the difference between them and stars.
I’m pretty sure they knew a heck of a lot. Just take a look at this “2000 year old computer” made to track the planets. The Antikythera: ruclips.net/video/jSQNEPbQOiI/видео.html
Not bad for a bunch of “relic mystics.“ Plato’s philosophy shows he knew things about the physics of earth that have only been proved in the last year or two. Cube theory anyone?
Good, clear video and explanation but tghe song ugh.
Hello!
I been born in Family civil air craft worker . My Grandpa his name is Gleb. Efemivich. Izmestev. August 18 hi is been killed in Deutschland after he are get bunch of astronomy tools to museum in Deutschland! After his will I'm is only one in will. Now couple years ago I been robe on one same tool in 2017 he get me on knee. So interesting is his two brothers been killed in same year. And he are die in 18 August day of civil air craft day celebration! My name is I.A.Stalbun.
lunar and solar eclipse happens every day on earth but at different locations, is that correct?
No, definitely not.
When moon completes one orbital rotation, will it cause solar eclipse somewhere on earth.? I have a lot of confusion about eclipse cycle
It probably stems from a confusion of the lunar orbit, which is not coplanar with the ecliptic. Just google it and find a picture of the moon's path around the earth and it will make more sense.
Ohh... . Now I got it. That the orbit is tilted. Thank you for clarification. :)
e
Not stars or planets, they are giant molecules.
Kya hindi dol sakte ho sir hame bhee padna he
“While this notion seems utterly ancient to us now……”
Unfortunately, the notion of “us” being the center of everything isn’t an ancient thought to a vast amount of humans to date. It’s amazing to me that there are still people who believe the religious view of our solar system and our universe. That a god created everything from nothing. It just poofed into existence because a god “mind-thought” it all here. With all the knowledge available, indoctrination and willful ignorance is prevalent. So frustrating and sad.
8:00 my only concern about this video is that it favors the northern hemisphere when describing "Summer" in July and "Winter" in January. Can the Southern Hemisphere get some love?
Why is there a plane in the solar system? What don't the planets fly around like electrons to a nucleus?
check out the tutorials earlier in the playlist regarding star and system formation. while you're at it check out my general chemistry tutorials, electrons don't do that either!
@@ProfessorDaveExplains I just watched all of those though
@@ProfessorDaveExplains but thanks for responding atleast, you're a cool dude
Sir aap English me hi hamesa bolte ho
But what happens if you tilt the earth 89 degrees? j/k I just watched the debate with flat earth Dave
So during summer solstice and winter solstice earth is full of heat and ice
In equinox its Normal
God spoke existences
5, then he did backflip everybody clap real loud
Winter comes when the gods are looking away
This whole video is an unproven theory. Wild.
Actually it's basic astronomy knowledge that has been known for thousands of years, and you don't know what a theory is. Wild.
May I ask you professor? is it possible to throw 10,000 letters in a table and hope it to become a book?
Um, what?
@@ProfessorDaveExplains Another basic question from a theist threatened by science
@Budget Couple Tours
What's that supposed to be? A "gotcha" question?
You have just lapped up the cesspool effluent of your preachers. No actual thought.
"Random" doesn't mean what those "preachers" have told you.
Please, either go and learn or GO AWAY!
यूट्यूब चैनल को सब्सक्राइब कर दो तुम्हारा इलाज है क्योंकि तुम स्कूल पर नहीं होना वीडियो में देखने
So… does polaris follow the earth around the sun?
Um, no.
I'm no expert, but I assume it's just really far away, making the earth's movement really small in comparison
Every 72 years polaris deviates by 1 degree.
I have yet to hear a satisfactory explanation of the extreme coincidence that the moon is the perfect distance from the sun relative to the size of the sun to eclipse it perfectly. It is as if an intelligence made it that way for human benefit.
It's not perfect. It's approximate.
GET DOWN ITS A CREATIONIST BOMB!
Its not perfect, its an approximate distance as Prof. Dave said
We sometimes get annular eclipses where the moon crosses over our view of the sun and covers the center, but leaves the ‘sun ring’ behind.
In a total solar eclipse we only see the corona of the sun.
very basic but quite clear materially speaking. on the contrary, why expulse any reference to spiritual matters like gods and spirits ? god-sun being symbol for executive power, moon-goddess and women fertility then legislative power are obvious too. why put up laicism while astronomy is everything behalve laicist ?!
then come wrong conclusions : heliocentrism is much more ancient than geocentrism. secondly, day and night are two different worlds having two space-time ratios, not just one. thirdly, animals breeding and plants blooming through the year then theories of cycles finally merged. why change history ?
lets keep it basic ok but keep telling the truth about sapiens' awareness and own position in the cosmos. our ancients calculated all of that because they intended to get closer to the gods and the spirits presiding life. science comes much later.
if you make this video again we will be pleased to show it to our disciples and pupils. thank you. ayala & yami, shamanes associate
Um, what?
Watching this video god😰😰😂😂