Tom Wujec demos the 13th-century astrolabe

www.ted.com Rather than demo another new technology, Tom Wujec reaches back to one of our earliest but most ingenious devices -- the astrolabe. With thousands of uses, from telling time to mapping the night sky, this old tech reminds us that the ancient can be as brilliant as the brand-new.
TEDTalks is a daily video podcast of the best talks and performances from the TED Conference, where the world's leading thinkers and doers give the talk of their lives in 18 minutes. Featured speakers have included Al Gore on climate change, Philippe Starck on design, Jill Bolte Taylor on observing her own stroke, Nicholas Negroponte on One Laptop per Child, Jane Goodall on chimpanzees, Bill Gates on malaria and mosquitoes, Pattie Maes on the "Sixth Sense" wearable tech, and "Lost" producer JJ Abrams on the allure of mystery. TED stands for Technology, Entertainment, Design, and TEDTalks cover these topics as well as science, business, development and the arts. Closed captions and translated subtitles in a variety of languages are now available on TED.com, at www.ted.com/translate. Watch a highlight reel of the Top 10 TEDTalks at www.ted.com/index.php/talks/top10

[@tifanyleetv]

Interesting that the pole star never changes while we are hurtling around the sun racing across the universe while wobbling crazy on our tilted axis and spinning wildly around... and yet the same star above us every night for thousands of years....

[@nf7747]

Ya that is very amazing, almost like we are on a flat plane with the stars projected in our sky like he demonstrated in his video.

[@tifanyleetv]

@@nf7747 yes! Exactly like that!! 💯

[@AS-ih2dk]

Like earth ... But flat. You know, like we measure and observe.

[@tifanyleetv]

@@AS-ih2dk I like that! 😁

[@luis-alvarez929]

Welcome to true earth which looks and feels nothing like a spinning ball in fake space

[@thisismeagain86]

What most people forget to mention the beautiful scientific history of the divice is that the name Astrolabe comes from the Arabic (Al Astarlab) which comes from the Persian (Sitara Yab) which means Star finder, star tool , star instrument, star access. in light of scientific integrity its crucial to note that the Astrolabes were perfected by the Arabs Universities in middle-ages (13th - 14th century), by Predominantly Persian scholars based on the rudimentary Astrolabes that were first invented in Egypt during Ptolemy's time and the first work was done by the Greeks. these entered Europe through Islamic Spain. thats why the oldest Astrolabes are always in Arabic. From Greek - to - Egypt - to - Byzantium - to - Persians - to - Arabs - to - Moors in Spain - to Europe The Mater comes from - Um (mother) The Plates - Lawhat (Writing slate) Rete (web) - from - Ankaboot (spider) Central Pin - from Fars (mare or) Faris - (the rider) Ruler - Al Idada (the ruler)

[@LiveSounds11]

All good.. but the Greek to Egypt part? The Egyptians were looking at Stars before there was a Greece and lets call it Kemet not the Greek name (Egypt). 🙏🏼

[@k.s.3748]

@Tons The Greeks invented it, long before Islam.

[@vantagemedicaltrans729]

100%correct .It’s funny how they hide the fact that Arabs gave them everything . What hypocrites

[@stonebrother3751]

"Knowing your relationship with the sky" Exactly !

[@nyclear]

Anyone agree with this: Not knowing much about the night sky does create some agitation within my being. Not knowing my surroundings on a basic level feels unsettling. I never realized this until this video. So thanks!

[@JDSutton7]

Great presentation. One of the best I have seen on TED. Thank you

[@Ongytenes]

This is something I would like to learn one day. A sundial can give us the time during the day but would fail at night. Tech is a two-edged sword. It can be wonderful, easing our labor. But how people adapt can be a problem. As the lecturer in the video spoke of how people lost the understanding of the movements of the heavenly bodies, so have others lost something when new tech came about. A few generations after the calculator came out; it has produce so many that don't even understand fractions. I had a person who had already graduated from high school insist that 1/4 was larger than a 1/3. His argument revealed to me that he didn't even understand the concept of a fraction. So many cashiers now can't make change unless the machine tells them what it is. Schools are now teaching new algorithms (new math) to cope with children not mastering basics like the multiplication table. New algorithms like "reasoning" (I call it guessing your way to the answer) may work but it isn't efficient as it requires more steps. I suspect one day when self driving cars are mandatory, (and likely be safer) driving a car will become be a lost skill for many if not most people. Imagine 20 years after the teen takes a two week course to get a certificate showing they know how to drive a car. Then they don't drive a car for the next 20 years and one day they are caught in a snowstorm. The car pulls over to announce there is a malfunction (frozen sensor?) and goes into manual mode. The driver has no reception to call for help and is forced to drive or freeze to death. This is the problem with technology. People tend become too lax and lose the ability to cope. GPS/Unable to read a map, Spell-checker/inability to spell, Computers/lost manual research skills etc. I had to show a 16 year old how to use an actual dictionary. His argument was he didn't need to know how as his cellphone will do it for him. But if the battery is dead, or there is no reception, then he remains ignorant. I don't blame the tech though. I just insist on teaching everything from the use of technology to hands-on skills to cope without tech. It requires discipline to do this as most kids tend to be hedonistic. Who knows? The knowledge may even save a live one day.

[@seven471]

"Imagine the Earth is at the center of our universe. " Psalm 104:5: “He set the earth on its foundations; it can never be moved.” Ecclesiastes 1:5: “The sun rises and the sun sets, and hurries back to where it rises." It IS the center of the universe.

[@shoshanafox727]

Yup 🙂 👍 👍

[@Truthiness231]

Totally eye-opening! I remember - vaguely - having to learn about this contraption in 8th grade History class. All we had to go on was the term "astrolabe" and a horrible definition as to what it was. Glad I can finally see one and find out not only what it looked like but how it was used. Thanks for filling one of the voids left from American public schools for an autodidact who likes to do that sort of thing. ^.^

[@zangetsujoo]

I want an astrolabe for christmas, A great example of form and function combined.

[@Shaunt1]

Amazing what they came up with way back then!

[@azndude3600]

Great lecture!

[@captcaveman4201]

i also like the looks of the device!! such cemetrical patterns are possible because the universe is a fractal.

[@McPrfctday]

The real Golden Compass... coool!

[@irinesiraj]

Very impressive! First smartwatch 😉I now wish I had some knowledge on astronomy 😀

[@renukote]

Irine S here is a little help. kzbin.info/www/bejne/p5OUYaOVlL5qeKc

[@aalayahpearson5974]

Wow this was a long time ago

[@orphanoforbit7588]

It`s not a watch.

[@MiguelLopez-tt9pq]

How high are you supposed to suspend it? Won’t the altitude of the celestial object change depending on how high or low it’s being held? I’m a bit confused if somebody could please enlighten me.

[@GetMeThere1]

Of course....they wouldn't work too well in cloudy skies. Otherwise, I have to admit, this is one of the coolest things I've ever seen.

[@moxiousmayhem42]

A very interesting viewpoint on technology.

[@mmedefarge]

We do grow more and more remote from our surroundings. A co-worker once asked me for directions. When I mentioned heading N. or E., she told me that she didn't know where those were, even though she'd driven there. I wound-up having to draw a street map.

[@lotanerve]

All with no wires. Amazing.

[@orrin2002]

I think that you raise a good point, really progress is a form of change. You could think about it as the vector of change if you wish. The counter point being oscillation. I know theses are very mathematical terms to try to use to describe human endeavor, but why not they seem to fit.

[@warrior82nh]

You have any article on the astrolabe?

[@jonathanshaw3755]

I thought Chaucer invented it but………..330 B.C.? Weird, right? And the sky was projected on a sphere? No it wasn’t. However, it did work perfectly with the earth set up as the center of the universe and it works today!

[@redahayani]

no greek no chaucer, astrolabe invented by muslim

[@Scientists_dont_lie]

This thing works assuming the earth is flat and stationary with the heavens spinning around the earth. Exactly what people believed back then. This is flat earth technology.

[@mland005]

@@Scientists_dont_lie exactly what people believed back then and exactly what dummies today reject.

[@2sunami]

credits to the real Astrorlabe inventor, first man to ever assemble a functional astrolabe. Al-Zarqali (Arzachel) [1028 - 1087]

[@mrolesen604]

Truth Humanity Then there is a slightly longer version of the lecture where we hear the first one is 2300 years old, but it was the Arabs who corrected the small mistakes and fine-tune it and made the first detailed and perfect version

[@maxfine3299]

@@mrolesen604 more perfect, as astrolabes aren't inpossibly accurate

[@trippin414]

The first astrolabe inventor was Greek and his name was Ίππαρχος (Ipparhos) from the island of Rhodes in 2nd century b.C. The word astrolabe is Greek : αστρολάβος. It"s sad when in videos like this one you don"t hear the information and the history that lies behind such a magnificent device.

[@ethanlamoureux5306]

I think you are wrong. The astrolabe was invented in the BC era.

[@user-zp5po3ee7v]

@@trippin414 this not true first astrolabe Arabic

[@SpinningSandwich]

@kamratframjandet The sun works well during the day (hence the sundial), but the astrolabe helped a great deal at night. Conversely, the seafaring world had to wait for an accurate clock system to tell them the time so that they could use the reverse process to determine their longitude.

[@BEARPREPPER]

Awesome! Really smart people!

[@canadianmaple09]

When he asks how you would check the time, he mentions the iPhone. When he talks about the cost of an astrolabe, he uses a reference to MacBook Pro. Holy shit! Could we have another shameless plug for Mac please?

[@914Rocky]

What did one do when it wasn’t night time? Also, I can’t wait to check out a more detailed video explaining how this works. He didn’t quite reach me with it.

[@steinfi3]

Fascinating

[@mmedefarge]

Yes, at night it's usually in the eastern sky where I live.

[@freesk8]

wonderful! "Does anybody really know what time it is?" Chicago

[@jonathanshaw3755]

I think it’s Saturday, the 4th of July.

[@MyChihuahua]

@@jonathanshaw3755 and you would be wrong.

[@Th0usandMaster]

6:22 in the heaven? where is it?

[@mmedefarge]

I don't drive. I take public transport or walk. I don't walk around with a compass but I do like to know basically where I am on the cardinal points. It's helpful to know when you're travelling around, so using the sun or even where the position of the space station is in the sky is helpful.

[@hijirikirishima]

@megalibra82 Would this be the same Wikipedia that says it was invented by the Greeks around 150BC?

[@mmedefarge]

I'm usually out the same time in the evening so I thought that this was perhaps why I see it in the eastern sky. It's so very bright & unblinking, I didn't think that it was a planet because it makes no difference what time of year it is. I'll check out the nasa site.

[@MrFungus420]

@SingleSpiral TED Technology Entertainment Design. This is incredible technology, It is entertaining and it involves something with incredible (and beautiful, in my opinion) design. IT fits TED perfectly.

[@RarewareLover]

Yes, it was his interpretation that all change is progress and all progress is change that seemed too simplified for me. I always thought of these as two separate words with two separate definitions. Progress always progresses, but does change? You could make the argument that everything we see progresses because only nonexistence is true stagnation, but I'm just talking about the meaning of two words and what they represent.

[@magnetocat]

@megalibra82 he did mention that they date from ~300 BC or so.

[@aranyakm]

The astrolabe shows local time, the iPhone can only show standard time. It's different.

[@Obi1kanObi]

Actually it was extremely interesting how in the 13th century they had already made a calculator and practically a computer. But I know what you mean because I too was expecting more about the history of its making and about the significance it had to the Muslims but either way it was very nice

[@captcaveman4201]

yes that is a very very good place to start..

[@chungdha]

Do you look at time on your Iphone? I tell time by looking at my watch!!!

[@DIProgan]

Good vid.

[@robwilkinson8497]

got one for a Christmas Present, will it work for the southern hemisphere?

[@Notsorandomnumbers]

Does anybody really know what time it is?

[@NekoMouser]

I don't think anyone ever claimed it was. The speaker referred to the "first technical manual in English" on how to build one. He never said the author of the manual invented the device, nor that there were not pre-existing manuals or devices in languages other than English. He was only pointing out that the first instructions on how to build the device in his (and most of the audience's) primary language were targeted at an 11-year old child.

[@Scientists_dont_lie]

Lol! This is great. These people are trying Desperately to NOT SAY "It works by assuming or imagining the earth is flat and stationary with the heavens attached to the hemisphere dome. They didn see earth as a ball at all!

[@luis-alvarez929]

If he says its flat and stationary he could lose his job and funding 🤷‍♂️

[@paullayfield]

It uses stereographic projection which allows you to map a 3D sphere on a 2D flat plate. They have multiple plates for different latitudes stacked inside & the face plates are switched according to that. It measures the altitude of stars above the horizon & has 2 parts to show the star chart. 1 is the view of the sky to the observer & 2 is the celestial sphere around the earth & wouldn't work for a flat earth. Stars above the north & south pole are always the same & just spin. Stars in the east & west move across the sky as earth spins & switch views from winter to summer

[@luis-alvarez929]

@@paullayfield stars above the south and north pole always being the same is proof enough we dont spin and travel in 4 different speeds and directions like they want us to believe.

[@luis-alvarez929]

@@paullayfield in fact on the south they tell us : "there is no bright southern star to mark the south celestial pole. Making it unusable for navigation porposes" How interesting we can only use the north star polaris as the center and all the other stars circle around it , just like described on a non rotating and stationary earth.

[@paullayfield]

@@luis-alvarez929 you can use any star that you can identify. Also starts above the north & south pole not changing & spinning in a circle while the east & west alternates would indicate a spinning motion. I'm not worried about what the shape of earth is, and either shape being confirmed would get the same reaction of oh, ok. Whether it's a flat simulation or inside out triangle, I'm here either way, besides that, technically you can't even prove anything exists outside of your thoughts & there is no shape to anything.

[@jenolsen82]

does it say anything about whats going to happen on 12-21-12? rhetorical ...

[@karturku]

I agree but still it was quite informative...

[@kamratframjandet]

I usually know quite well what time it is just by looking at the sun, unless I'm totally confused about which way is north or south...

[@MyChihuahua]

But I bet you have no clue of how to know the true month and day.

[@shagster1970]

To all those negative comments- What message were you expecting? I bet you didnt know of the astrolabe! I learned something therefor it was of interest. Side note: Its interesting to see the evolution of man's progress in technology. And yes - I was amazed at how they could come up with this stuff even TODAY let alone so many years ago. I would wager not a single high school (students) in the USA could create such a device today if asked.

[@mland005]

Not a single high school student understands our true cosmology. I think the presenter understands, but of course he didn't say it. Had he, he would never have been allowed on the stage. Our technology today really just enables the ignorance that has completely taken over our society. We are not spinning, wobbling and hurtling through space on a gigantic testicle.

[@HiAdrian]

What a beautiful device!

[@trippin414]

The first astrolabe inventor was Greek and his name was Ίππαρχος (Ipparhos) from the island of Rhodes in 2nd century b.C. The word astrolabe is Greek : αστρολάβος. It"s sad when in videos like this one you don"t hear the information and the history that lies behind such a magnificent device.

[@Th3Pr0digalS0n]

the device requires the earth to be a flat plane, and the sky to be a dome for it to work... it does work... therefore, the earth is a flat plane, and the sky is a dome.

[@Kaepsele337]

It does work, but only at the latitude the plate was designed for. for different latitudes you'd need different plates. It uses your local environment as a reference point and this can be very well approximated by a plane. The position of the zenith on the plate tells you which latitude it was designed for. This is the case because you need to know the angle of the plane relative to the axis around which the stars rotate. In fact you can use this to reconstruct the shape of the earth, by seeing how the angle of the tangent plane changes relative to this fixed axis as you move further north or south. I encourage you to do this experiment on your own, and you don't even need an astrolabe for it. Simply confirm that the night sky seems to rotate around a fixed axis that goes roughly near the north star. Then measure the angle of inclination of that star. This is easier and more precise with an astrolabe, but you can also use a simple board tied to a string. Hold the string just between you eyes and hold the board at such a distance that it's bottom end covers the horizon and the top end is at the star. You can measure the distance by measuring the string. The angle is then arctan(boardheight/stringlength). Then travel 556 km due north and repeat. If the angle you measure changes by 5°, then the earth is a sphere with a radius of 6371km. If the earth is flat, the angle will not change at all. The relation is linear, so if you only travel 100km, the angle will change by only roughly 1°. So the more precisely you measure, the shorter you have to travel. Of course you can also call someone that you trust that lives further north/south. And the assumption that the sky is a dome works because the stars are far enough away, such that the parallax caused by the movement of the earth is irrelevant.

[@Th3Pr0digalS0n]

@@Kaepsele337 but, if the world was round, as your calculations assume. why can we see 20-30 miles across flat water? If we really are spinning through space, and around the sun, and chasing the galaxy as your calculations assume, Why do the stars proceed in an orderly circle around the north star every night for thousands of years? nothing in observable science agrees with the globe earth model. the existence of Flat star charts, astrolabes, and sextants all prove that the flat earth model is the correct one. however neither one of us can prove our assumptions, as you cannot leave the earth and I cannot travel to the edge of the dome. so lets just agree to disagree.

[@Kaepsele337]

@@Th3Pr0digalS0n Okay, so the distance of the horizon you can actually easily calculate on a globe. Draw a diagram of the round earth, with a person standing atop of it. Then draw the right triangle from the center of the earth to the eyes of the person, from there a tangent line to the earth and then from the touching point of the line back to the center of the earth. If the radius of the earth is R and your eyes are at height h, you can calculate the distance of the horizon with a simple Pythagoras as sqrt( (R+h)^2 - R^2)). The stars seem to spin orderly around the north star, because they are basically stationary and we as observers on earth are actually spinning. In my entire life I have not made any observation that would contradict the globe earth model. And I'm the kind of person that actually thinks about this stuff for fun, so I think I would have noticed if there were contradictions. Of course we can agree to disagree and just move on with our lifes, but I imagine that thinking the earth is flat must be awfully alienating in a world where most people are convinced it isn't. Most people don't appreciate that level of scepticism. So I thought it would be nice to give you the chance to change your mind in a discussion where I don't appeal to authority.

[@billkeithchannel]

@@Kaepsele337 So where does the 'R' value come from? That value is derived from circular logic and just presumed.

[@Kaepsele337]

@@billkeithchannel R is a model parameter. If you want to derive it from scratch, you can take measurements on how far the horizon you can see to fit that parameter. In this case the question was just how the globe earth model would describe the horizon as we see it. This model has a well established value for R. If the result from the equation I mentioned does not give the correct result with the official value for R, then the official model would be falsified. That experiment alone cannot tell you the shape of the earth, but it could be used to falsify the globe models, if it gives results inconsistent with that model. The other commenter suggested that there is a contradiction here. To be honest, with the values he provided, I get that you'd have to be roughly 120m above the ocean to have a view that far, and just standing on the ground you should be able to only see about 5 km, but I have no idea where his data comes from.

[@btwbrand]

The commercial wasn't about going green or saving gas, or any thing of the sort. It's about a solution to a problem. Too many people on the road when they do not need to be. The addition of a simple fee was all that was needed to deter those with no real reason to be out driving and facilitated faster, easier traveling for those that did need to be on the roads.

[@MarvelGirl100]

What About Hypatia? I thought she created it in Alexandria

[@K-Effect]

Would you please put your 24/7 feet back up, I really enjoy watching that

[@GiffysChannel]

how come i have never heard of this?

[@040stokstaart]

Because this magnificent piece of work is based on a flath motionless earth. Thats why you never heard of this. And probably because its an invention of muslims.

[@GiffysChannel]

@@040stokstaart you might want to watch the video again. It ONLY works with the 3D model of the galaxy. I can't tell if that's an antisemitic jab at the muslims or not?

[@040stokstaart]

@@GiffysChannel I don't need to watch the video again. What has a 3D sky on a 2D plate has anything to do with what i said. An astrolabe is based on the movement of celestial bodies in the sky converted to angles on the plate, to calculate and measure so many things. A spinning Ball earth teach us the opposite which is the stars and other bodies are not moving and that the earth is spinning which is absolute false.

[@GiffysChannel]

@@040stokstaart hmm, are you saying the argument is either the earth is spinning and everything is (relatively) still or the earth is still and everything is moving around it? I don't think one can be proven over the other. Personally, I see everything moving in unison as a single machine.

[@040stokstaart]

@@GiffysChannel yes thats what i wanted to discus. I incline to the geocentric model. Earth the center not spinning and everything revolve around us. Just like how the Astrolabe works.

[@2007Tubes]

I am always amazed at how people put forth such amazing technology and such, at the time, abstract thoughts. However, if this ted talk was truly only about the astrolabe it was an ill conceived ted talk. It is an amazing device, but a ted talk should move you. Maybe if he did not use an iphone app to write his speach it might of had been more directed. So much could be said about the invention of it, rather than the expense of the object itself. Who cares what it costs?

[@qalexk]

It works because it represents flat earth model, not a globe

[@dahmmandatruth4692]

and Orion has just popped up for me in Maine. right of the rising moon and that's right of the birthing sun.

[@RarewareLover]

I must disagree with him that progress is just another word for change. Even though we cannot have progress without change, not all change is progress.

[@evilpatrick9562]

Well thats game of words .

[@seenvision]

did not know these existed

[@0grilo0]

i wonder if it ever dawn on these people that this works so perfectly because the earth is flat.

[@tafden25]

to bad my astrolabe has such low reception where i live.

[@TheRealMichaelBaer]

Affirmative =)

[@adolfotapiagallardo]

extraordinaria simplicidad en la exposición para un dispositivo aparentemente complejo! felicitaciones! en la computadora se puede instalar el programa stellarium con el que se "descubre" que el astrolabio es una ingeniosa combinación de coordenadas ecuatoriales y azimutales! stellarium.org/es/ en mi celular tengo sensor magnetico asi que trabaja una app de brújula y entonces también funciona perfectamente la app SkEye que recomiendo usar! saludos desde el peru

[@solace1369]

Could one not program an astrolabe on the ipod?

[@dapnd]

dude, his point is we over-rely on technology, and we think that the only way you can do simple tasks is to use the newest, "best" technology. he's saying that we think we're so advanced because we have new gadgets, when in fact there are old ones that are jut as good.

[@SamReed333]

Shoutout to John B McLemore

[@dapnd]

as a follow-up, where we would say the stupid phrase, "there's an app for that," the old folk would say "learn your stuff, you damn yuppie." well... something like that.

[@andresbujosa7385]

The only issue is that they only work in one location, right? Very impressive nonetheless

[@seven471]

No

[@roidroid]

strangely, in this day and age if someone asks what time it is - the first thing you do is check their IP address to see what country they're in. Strange times :)

[@theyeeter5995]

almost 19 million subs 100k veiws and not even 1k comments

[@Leopoldo888]

agree.

[@dahmmandatruth4692]

it's time to say I love myself:) and you

[@PFWYG]

well said =)

[@duncankelly4354]

He says imagine the earth is at the center of the universe at 2:20. The ancients BELIEVED the earth was at the center of the Universe. They also knew the Earth was flat. That's how they built the Astrolabe. It worked then it works today. What do people in the Southern Hemisphere do? People in Australia can't see the North Star.

[@howardman3926]

Yes, that's why Astrolabes had different plates for different latitudes, ergo they knew the Earth was round. They knew it was round, but you simply couldn't have created a device with another dimension (being latitude) that could easily be portable, unless they used different discs corresponding to different latitudes.

[@duncankelly4354]

@@howardman3926 Look up "Axis of Evil" in astronomy. Hmm, center of the Universe confirmed. Twice.

[@howardman3926]

@@duncankelly4354 That video doesn't support your argument at all. In the ending card of the video, there is a link to a video of him talking about how Earth has no special position in the universe.

[@duncankelly4354]

@@howardman3926 Believe that if you want but there are several papers out there debating your statement. Google it.

[@duncankelly4354]

@@howardman3926 Where did you see that Howard? Can you point me to the evidence that different plates were used for different latitudes?

[@costycuzzin]

Use 2: paper weight

[@btwbrand]

It is a solution, how could you not see this? If there is a parking lot full of people that aren't entering a store the parking lot serves, then that's a problem. Imposing a fine to deter people from parking in said lot if they have no valid use in the lot is a solution. The same concept and proven to work here. A by-product of the fines was an increase in public transportation use, and car-pooling. Both of which save people more money than the fuel it takes to travel there separately.

[@costycuzzin]

whatever, you get the point. timex, it takes a licking and keeps on ticking

[@illelekt3577]

astrolabes are geocentric instruments

[@StratOnFire]

Is this an insult? lol

[@Scientists_dont_lie]

@@StratOnFire no i dont think so.

[@billkeithchannel]

Change: Social distancing is not social, just distancing. Say no to psychological warfare doublethink.

[@Scientists_dont_lie]

Social distancing is social engineering

[@billkeithchannel]

@@Scientists_dont_lie I have the feeling Dave linked this video in the app. Gonna be a slew of new comments.

[@MRSketch09]

@Vid That's an interesting device. But what was the mans point? Is he saying that were relying to heavily on technology? that were becoming dumb asses because everything is becoming automatic? We need to think more? Surely there was more to this, than 'lets all look at the pretty replica tool, that cost a few grand'?

[@MarkBellisCanada]

Megacool! Made me realize that Islam helped the development of Astronomy because Muslim travelers had to figure out the time for prayers and the direction to Mecca!

[@ethanlamoureux5306]

So they could recite their blasphemies towards the city in which lies the idol which their false prophet told them is the house of their god.

[@mjeshaw]

The thing he keeps calling the "reet" is the rete, (which simply means net in Latin). It should be pronounced ray-tay.

[@lowslowflyer77]

So this Earth is stationary!

[@YoLninYo]

Did you manage to notice how he completely skipped giving any credit to it and tried to give an impression that it was an englishman who came up with it. Also, he kept bearing "our forbears"... It is like pointing out that the first transister radio was built by a japanese company, thereby implying it were the japanese who invented the device, even though it was indeed Shockly, an american. It was a shockingly dishonest thing to do, and I did not expect a TED presenter to stoop so low.

[@haruner_]

I came here from Game of Thrones

[@RonaldsSulcs]

interesting.

[@kreaturen]

@fcouperin: Yeah, but I think that's something we should contemplate on our own, otherwise it would just be moralising. After all he said we gain something as well as loose something. It's plenty of stuff to occupy our minds with still. Also in the past, most people were really dumb, and just a few really smart people had to do all the progress for us! ...Probably while those average smart people, where just preoccupied with checking out the time :P A lot of work ,just to get on with your day.

[@HiAdrian]

come on nick, i've already had my share of negative today.

[@Dayvit78]

I really wanted to be interested by this chat because I like this era of history, but it wasn't really interesting... Tom tried though.

[@corydorastube]

He works for Autodesk, not for Apple.

[@mahfeww]

An astrolabe requires a flat plane and a domed sky. If you go just one level further into the math and geometry that goes into using this, you would see this. This guy couldn't say this because it's against the narrative

[@AS-ih2dk]

Flat earth.

[@Kaepsele337]

It's true. It makes the base assumption that you're comparing the position of the sun and stars to the tangent plane at your position on the earth. This is why you need to change the plates when you go further north or south, because the angle of the tangent plane changes. This is because the earth has curvature. To put it simply: Since the device assumes a flat plane for the construction of the plate but the earth is a sphere, they had to use different plates for different latitudes. I don't know what kind of narrative this is supposed to go against (although I can guess what you're implying, obviously).

[@jorgkirchhof7225]

It seems you didnt watch or understand the video. The Astrolabe or pleniSPHEREA is based on the stereographic projection of the globe SPHERE and the celestial SPHERE onto the equator plane via STEREOGRAPHIC PROJECTION.

[@mahfeww]

@@jorgkirchhof7225 difference is, when you travel irl with the stars as your map, it's all based on a flat plane. One can say ball earth in a space vacuum all they want but that's just geometrically impossible. The moon however is all lands and firmament superimposed on another. Things like that or how consciousness works will never air on Ted talk. If you knew how many people get canceled over the truth.

[@jorgkirchhof7225]

@@mahfeww again... In contrast to you, I have created a computer programme already to generate the different parts of an astrolabe. From the Rete to the tympani. And of course I used the stereographic projection to do this and of course I used the sphere to do so. Your claim that the Astrolabe is a proof of flat earth, is just wrong and shows that you NEVER learned how an astrolabe works and how it is made.

[@Katalyzt]

Cool ★★★★★

[@TheWizardu75]

Alexandre Astier

[@AS-ih2dk]

Literally just proved geocentrism and flat earth.

[@drivventodrumm1]

Proving the sun moves above us...

[@hishamhabli3876]

1300 AC with one of these bad boys in your pocket to cheat on a math test

[@captcaveman4201]

a good TED presentation.. Finally!! but the commercial at the end about the traffic is the dumbest thing i have seen..They charge people to drive their cars!! WTF !! they scan their licence plates and send them a bill in the mail.. WTF !! because they are soo concerned about traffic and pollution. but billing people doesnt FIX A DAMN THING! are they putting their efforts into having clean electric, hydrogen,solars cars? NO they put their efforts into scanning people licence plates TO BILL THEM

[@roidroid]

Is this guy on loan from Steve Jobs' harem? He has needlessly mentioned 3 Apple(tm) products. He says MacBook(tm) instead of "Laptop", and iPhone(tm) instead of "cell phone". What a tool.