Extracto de la transcripción automática del vídeo realizada por YouTube.
- Good morning, everybody. And I want to start just by saying that despite some really heroic efforts on the part of the crew here, presentation's not going to have audio this morning, sorry about that. So I'm going to need help with sound effects, despite karaoke last night.
Because there's some few key points in this presentation that need emphasis with sound. So, my name is Jeff Norris. And I'm really happy to be here. I hope everyone's having a great conference. We're all software people and we came here primarily to learn about software.
But this morning, I'm going to talk about something that I think is equally important in our work which is partnership. I'm going to tell you three stories of how partnership had shaped inventions from the great eras of exploration. Sea, air, and space. And I'm going to draw some lessons from those stories about how we should be forming partnerships in our own work today.
So, because we're getting a little bit of a late start, let's get started. My first story is from the era of maritime exploration. It is a time of great uncertainty in navigation. Our maps are confused by the fact that we don't really know where we are at any particular time.
Our position in a vessel is often up to the guess of a ship's navigator, and they often guess wrong with disastrous effects. And in 1707, the British government loses four warships and 2,000 men when the admiral of that fleet can't correctly determine the location of their boat.
This brings the empire to a point of desperation. And they form, they charter, a new Board of Longitude. And they offer the Longitude Prize, 2,000 pounds, or about five and a half million dollars, for the person who can bring the first practical solution to the Board of Longitude for finding longitude at sea.
Or, your position from east to west on the map. You see, latitude was never really the problem. You can find your latitude, well if you're an early mariner, even with a stick and string held between your teeth. And with something like this sextant here, you can find it quite accurately.
So, a sextant is actually a device that we use to measure the angles of things above a horizon, or the angles between celestial bodies. So, I'm just going to use my sextant here right now to measure the angle here of the sun over the horizon. And figure out the time of day, which is something that a mariner would have to do quite often with the sextant, and something that it's quite good at accomplishing.
In fact, if you were to measure the altitude of the star Polaris, or the North Star, over the horizon, you would actually have your latitude on Earth in the northern hemisphere. So, the ease with which people could find latitude using something like a sextant, makes it unsurprising that when they wanted to find longitude they also looked to the sky.
You may have noticed that the moon moves across the sky from east to west, just like the sun and the stars. What you may not have noticed, however, is that it moves across the sky a little bit slower. So you can see, so it just kind of moves this way. But the reason why it moves a little bit slower is that it's orbiting the Earth from west to east, the opposite direction.
Not fast enough to make it look like it's going the opposite direction, but fast enough to make it look like it slides across the sky against the background of the stars behind it. So when you're looking up at that as a mariner, if you had a sextant you could use that sextant to measure the angle in between the sun, sorry, the moon and a reference start like regulus.
And if you could find that angular distance then you could find the linear apparent visual distance between that star and the moon. This is called the lunar distance and it's critical in our first story. Because with the lunar distance, you can calculate longitude.
It's actually pretty simple. All you got to do is just account for the altitudes of the two objects in the sky, because that causes aberrations in their appearance. And don't forget the apparent diameter of the moon, because you see the moon changes its apparent diameter as it moves around in its orbit around the Earth.
And you also need to make some corrections for parallels because the moon looks different from placed on Earth. Just plug that into some simple systems of trigonometric equations which unfortunately, that's not quite right. I think it's more like this one.
But, you don't have a calculator on your boat. You're going to have to look up all these trig functions in a table because calculators haven't been invented yet. And while you're doing this, the wind is blowing, the sea is churning, and the moon is moving up and down.
And the problem that I'm just describing here is why even a skilled sea captain couldn't find longitude in less than four hours at sea, and why we need an alternative. And we do have an alternative. You see, on Earth, the sun is setting at one place at really one point during a day in any given day.
And so, it's like the sunset line is crossing over the Earth almost like the hand of a clock. And if you are out here somewhere in the middle of the North Atlantic, and you happen to know that the sun just set. So you just saw that sun drop below the horizon, and my some magical ability, if you knew that in London the sun had set exactly two hours ago, you would know your longitude on Earth because there's 360 degrees around the globe, it takes 24 hours a day for the sun to go around.
So each 15 degrees equals one hours of difference. So, if it set two hours ago, well then all you've got to do is going 15 degrees for one hour and 15 degrees for the next hour. You're 30 degrees away from London. This is actually the same as if you happened again to magically know what time it is where you are, I just showed you how you do that with the sextant, and what time it is where you left from.
So how do you do that second part? Well, you're probably thinking oh, I just need to bring a clock right, no big deal. Well the problem is, is that clocks of the time don't function very well on the rocking boats that were trying to cross the ocean. And so that unfortunately, is not going to work with the technology of the time.
However, these are what would become the two main likely approaches for solving the longitude problem. The lunar distance method and the chronometer. Or really accurate clock. And I'd like to introduce you to the two gentlemen who are the leading proponents of each approach.
So, on the left over here we have Nevil Maskelyne, He is a member of the British elite intelligency, an master astronomer. Formally educated, and all in on the lunar distance method. He's an astronomer and he believes that's the way to solve the problem. Over on the right we have a country carpenter by the name of John Harrison.
He taught himself a little bit of science on the side, fixes a few clocks in his spare time. This probably doesn't feel like too much of a fair fight, master astronomer, country carpenter. It's not, it's really not a fair fight. But don't count John out just yet, because he's got a couple tricks up his sleeve, still.
So, Nevil Maskelyne over here, he's got some really powerful friends, including Sir Isaac Newton, who tells the world lunar distance is the only method worth looking at when trying to solve the longitude problem. In fact, he is the de facto head of the Board of Longitude.
He's also the head of the community of astronomers who have convinced the British crown to build this. This is the Greenwich Observatory which you can just think of it as a temple to astronomy. It is a veritable castle, okay? The Royal Astronomers actually lived there.
And they justified it as expense by saying oh, build this for us and we'll solve the longitude problem. Well, John over here on the right, John Harrison, he didn't get that memo. Maybe he didn't travel in royal society circles enough. But he spent the next five years of his life building a sea clock.
And this is what he made. I want you to just take a moment to appreciate the incredible artistry and the amazing craftsmanship in his sea clock. There are many advances in this clock for timekeeping at the time. A revolutionary escapement, parts of this clock are actually made of wood.
And they exude a natural oil that lubricate the clock as it runs. It doesn't use pendulums, it uses a system of springs and counterweights in order to keep time at sea. Rather important again because this clock has to work on a rocking boat. So John finishes his sea clock, brings it to the Board of Longitude and demands the sea trial which is the condition of claiming the Longitude Prize.
[ ... ]
Nota: se han omitido las otras 4.141 palabras de la transcripción completa para cumplir con las normas de «uso razonable» de YouTube.