Chapter 790 Arrival at Point Nemo
The stars are so bright that even the howling of the wind cannot cover up their brilliance. They shine brightly in the dark night, guiding all lost travelers.
Following the direction pointed by Bifang, everyone was fascinated.
Someone once took a time-lapse exposure photo of the starry sky in the northern hemisphere. The stars move and the trajectories of the stars in the sky form concentric circles because of the rotation of the earth.
Only the star at the center of the circle remains unchanged in the field of vision because it is located on the extension of the earth's axis.
This star is called the North Star, and it is also an old friend of ours.
For observers in the northern hemisphere, the North Star remains stationary, while other stars revolve around it.
etc……
Northern Hemisphere observer?
Some audience members smacked their lips, wondering if something was not right.
After a while, someone suddenly realized that wasn't Master Fang in the southern hemisphere?
[Can the North Star be seen in the Southern Hemisphere? 】
[I slowly typed a question mark]
[Fuck, I just realized that Lao Fang is in the southern hemisphere. How can he see the North Star? ]
"When did I say this is the North Star?" Bifang laughed twice, "I never said this is the North Star."
“I just used the North Star as an example because the underlying logic is the same and everyone is familiar with the North Star, so I think it may be easier for everyone to understand.”
I'm stupid
[Feint]
【biubiubiu】
[Sorry, I don't understand what you mean by star. ]
So what star is this?
[So the Southern Hemisphere is the South Pole Star? 】
"There is no so-called South Pole Star. This star is actually the center point of the Southern Cross."
"The North Star is located on the extension line of the Earth's axis, and its distance from the Earth is very, very far, so far that the radius of the Earth can be ignored compared to it."
"So, if you look at the direction of the North Star from a certain location on the Earth's surface, the line of sight is parallel to the Earth's axis. Then, the angle between this line of sight and the horizon, that is, the elevation angle of the North Star in the field of view, is equal to the latitude of that location."
"That is to say, if you look for the North Star in your field of vision and find that it is directly above your head, that is, the elevation angle is 90 degrees, then it means that your latitude is 90 degrees and you are standing on the North Pole."
"If you look for the North Star in your field of vision and it is on the horizon, the elevation angle is 0 degrees, which means your latitude is 0 degrees and you are sailing on the equator. If the elevation angle is 30 degrees, it means you are 30 degrees north latitude."
[I mentioned this last time. I remember using a sextant.]
[Is Fangshen Sextant ready?]
[That was the sextant just now, right? ]
The audience remembered the strange object made of several thin wooden sticks that Bifang took out before he started calculating, and immediately understood its purpose.
Bifang did not deny it.
Fortunately, these simple gadgets were not lost in previous adventures.
"This is the process of determining the northern latitude. Although there is no corresponding South Pole Star at the southern latitude, we found that the center point of the Southern Cross can approximate the role of the South Pole Star."
"Although such observations are not precise enough, they are sufficient for navigation positioning."
Bifang pointed at the stars in the night sky. After careful observation, everyone discovered that this star was indeed quite different from the North Star. Although it was also very bright, there was a lot of brightness around it.
Due to the existence of the North Star and the Southern Cross, experienced navigators can easily determine their latitude with the help of appropriate measuring instruments. However, measuring longitude is much more difficult.
"Latitude is a series of parallels, and longitude is a series of lines that meet at the poles. "
"The earth rotates in the east-west direction. There is no east pole or west pole, so there is no east pole star or west pole star."
"However, the navigators still discovered a pattern. This pattern has nothing to do with the starry sky, but with time."
"We clearly know the concept of time zones. For example, it is 2 a.m. China time, which is 1 p.m. Eastern Time. If I know that it is 2 a.m. China time and 1 p.m. local time, then can I infer that my current time zone is the Eastern Time Zone?"
"Then, I can know that the longitude I am at is the longitude of the eastern part of the Ugly Country. Therefore, the problem of measuring longitude is transformed into the problem of measuring the time at a known location and the time at the current location."
[No, my head hurts.]
[Master Fang, please stop reciting. Please stop reciting.]
【Dream back to high school geography class】
【Learning is useless. Learning is useless.】
Bifang then started a series of analyses, his charcoal pencil moving non-stop, which sounded like both an explanation and organizing his own thoughts.
"The Earth's rotation period is 24 hours, which means it rotates 360 degrees in 24 hours, 15 degrees per hour, and 1 degree every 4 minutes."
"If you take the port of departure as the reference point, for example, if you depart from London, Greenwich Mean Time is used as the standard time, and the longitude of Greenwich is used as the 0 degree longitude."
"At a certain point in the voyage, Greenwich time is 1 a.m. and local time is 9 a.m., a difference of 8 hours. That is, the difference between this position and Greenwich is 8 times 15, which is 120 degrees, which means that the current position is 120 degrees east longitude."
"But there is a crucial question here. How do we determine Greenwich Mean Time and local time in the vast ocean?"
【Corona Bar】
【A clock?】
"It's a sundial."
The crew would place a sundial on the deck and use the direction of the sun's shadow to determine the time.
The ups and downs of the ship have a great impact on the length of the shadow, but have little effect on the change in the tilt direction.
Greenwich Mean Time is determined by clocks. When you set out from London, you set your clock to Greenwich Mean Time and never adjust it again.
[It sounds like it’s a little simpler than what Lao Fang calculated last time? ]
[I don’t know. Anyway, I don’t know any of them. Just listen.]
[I picked up a pen during class, and I never understood Fang Shen’s solution again]
Bifang shook his head again.
"It sounds simple, but it is difficult to implement because this method relies heavily on an accurate and reliable clock. Otherwise, the effect will be greatly reduced. Although the ancient Greeks invented the theory of longitude, due to the limitations of clock manufacturing technology, navigators were not able to accurately measure their longitude until the 18th century."
"Before that, there was even a law on maritime navigation that if a soldier casually told the captain about the route, he would be immediately executed. Because at that time, there was no way to determine your own route, and it was entirely dependent on the captain's experience and intuition. They only knew their latitude but not their longitude, until later reliable clocks were invented."
[Hiss, it’s all just guessing, right?]
[In fact, it is not necessary to know your longitude and latitude accurately for navigation. Lao Fang has a special need for this. At that time, as long as the direction was right, people just had to keep moving forward. There were also landforms along the way, such as islands.]
[Indeed, Nemo has no surface at all, which is the most frustrating thing]
"Therefore, for a period of time, the commonly used method was the lunar distance method, which was to calculate the universal time by measuring the angular distance between the moon and the stars. In addition, there were Davis quadrants, star-trolling boards and sextants, which were all methods for solving one's own position at the time."
"That's also why many famous watches today have a nautical origin. Because of the inconvenience of measuring longitude, navigators came up with an approximate measurement method, which is to look at the distance, which is the so-called nautical mile..."
"Many people may wonder why the distance of a ship must be expressed in nautical miles instead of kilometers or miles, which are common units. It seems that this is done to make things difficult for people. The speed of a ship must also be expressed in knots. In fact, this is to facilitate the determination of position, because the arc length of 1 nautical mile corresponds to 1 minute of the center angle of the earth."
[Oh, so that's how it is? ]
[When I did similar math problems before, I felt that the sea was very anti-human. Why did we have to create a special unit of distance and speed for navigation? Is this the reason?]
【I have learned a lot. 】
"Every nautical mile sailing north-south means a change of 1 minute in latitude; every nautical mile sailing east-west on the equator means a change of 1 minute in longitude; if sailing east-west on a non-equator, you need to multiply by the inverse of the latitude cos as a correction factor."
"The speed unit 'knot' also comes from this, 1 knot is equal to 1 nautical mile per hour."
"So, we just need to know the distance we are sailing..."
Bifang explained carefully without stopping his hands, rubbing the black charcoal pencil on the wooden board, leaving behind black charcoal ash.
The torches on the bow swayed in the wind, and human figures flickered.
Of course, distance calculation cannot be accurate. In fact, in the age of sailing ships, a positioning accuracy of tens or hundreds of kilometers is enough.
In addition, several methods are used in combination, compared and corrected with each other. Although it is not as good as GPS, it is enough for Bifang to reach its destination accurately.
Although Point Nemo is a point, it does not mean that Bifang has to sail through this point accurately to successfully cross the river.
Just being near it would mean that this mission is accomplished.
It doesn’t even matter where you go next, whether you go back or keep moving forward to the next island.
Through various calculations and steps, it looked like a big math problem had been solved on the wooden board, and even small serial numbers were marked.
Each serial number represents a calculation method used by Bifang to find out its location.
When three coordinates appeared, Bifang listed them, then verified them with each other, and finally breathed a sigh of relief.
In front of everyone, he shook the wooden board in his hand, circled a coordinate, then threw down the charcoal pencil, lay down in the Viking, looked up at the night sky, his tone extremely melancholy.
"My luck is finally good."
"Point Nemo, right under our feet."
Point Nemo...right under your feet! ?
The audience was stunned.
Here we are, are we there yet?
Everyone who originally thought that there was still some distance to go never expected that the mission would be completed like this?
Bifang put his arms under his head, feeling indescribably relaxed, and in an instant the world seemed wide open.
At the moment the longitude and latitude came out, the task finally changed on the blue fluorescent system panel, showing a semi-completed status above Point Nemo.
Just when his body and mind were completely relaxed, Bifang's eyelids suddenly became extremely heavy, and for a moment he could not even open his eyes.
The audience in the live broadcast room undoubtedly burst into cheers again, and barrages of comments emerged rapidly, sweeping across the entire screen. For a while, the actual picture could not be seen, but soon, some viewers heard some other sounds in the wind.
When the heat subsided a little and they could finally see the picture clearly, countless people were speechless.
Bifang actually fell asleep like this.
…
Not to mention how lively the Internet was, these were all routine operations for Bifang. When he woke up the next day, Bifang felt more energetic than ever before, and even the soreness in his muscles seemed to have eased a lot at once.
It has only been seventeen days since Bifang set out from Easter Island, so its speed can be said to be incredibly fast.
Bifang did not relax his vigilance. Although the most critical part of the mission had been completed, there was still a typhoon chasing him, so now was not the time to stop.
During this period, Typhoon Harold made a strong landfall in Vanuatu as predicted, causing extremely serious disasters.
Although there are several relatively strong storms in the South Pacific every summer during the active tropical cyclone season, it is relatively rare for a strong storm to hit a country at its strongest level like this year, which may indicate that the climate pattern in the Pacific is in an abnormal state.
For safety reasons, Bifang did not choose to return along the same route, as that would have taken him too close to the typhoon and was too dangerous, so he chose to keep moving forward.
Of the three islands closest to Point Nemo, Ducie Island and Easter Island are very close, while Mahe Island is too close to Antarctica.
Although going to Antarctica is far away from typhoons, the temperature will continue to drop, and Bifang did not bring enough warm clothes.
And the drop in temperature will also increase the food gap.
So after careful consideration, Bifang headed directly towards South America, which was farther away but more convenient.
Not many accidents happened during the period, and the danger dropped sharply as it was far away from the typhoon area.
On the thirty-first day, some fish finally appeared in the ocean, alleviating Bifang's food crisis. It also proved that Bifang was far away from that silent place.
Time finally came to the thirty-fourth day, and the first island appeared in front of Bifang, symbolizing the perfect ending of this crossing.
The canoe was rising and falling, and Bifang stood on the bow, gazing into the distance.
The small island in the distance is lush and green, full of vitality.
The setting sun falls below the horizon, golden light spreads across the ocean, and birds return to their nests.
Looking at the island right in front of him, Bifang stopped paddling and controlling the sail. He folded the sail, threw away the oars, and drifted with the current.
The collision and impact of the waves made a unique sound of the tide, which was the most common sound Bifang had heard in more than a month.
After thirty-four days, starting from Easter Island, we crossed the entire South Pacific, passed through the Pole of Inaccessible Ocean, and finally drifted across the sea to a small island in South America on the other side.
This is truly unprecedented. The opening remarks are no longer just empty words, but everything he has experienced!
