Heung-woo and Mia slept until midnight. Mia kept squeezing to Xingyu's side in her sleep. In the end, Xingyu was woken up by Mia's rubbing. The ignorant Xingyu thought that Miya was dreaming, but then he felt cold. The temperature around is very low, and Mia has the habit of kicking the quilt again. At this time, Xingyu understood why Mia kept squeezing to his side. Heung-woo hurriedly found the quilt that Miya kicked aside, and put it on Miya again. After this trouble, Xingyu didn't feel sleepy. Xingyu stepped out of the lifeboat and felt the bitter cold wind on the raft. At this time, Xingyu noticed that in the past few days, the temperature during the day has indeed dropped. It used to be hot during the day, but these days even when the sun is shining at noon, I feel cool. Originally, Xingyu thought it was the rainy season. But it didn't rain yesterday and it's still cold tonight. Xingyu vaguely felt that something was wrong.

At this time, Mia also walked out of the lifeboat wrapped in the quilt, but then jumped back into the lifeboat by the cold surface of the container. Seeing Mia's cute appearance, Xingyu also smiled and followed Mia into the lifeboat. When Miya saw Xingyu coming in, she immediately complained: "Why is it so cold!" Where the hell have we drifted? Xingyu replied with a seemingly heavy weight: "We may have drifted across the equator and into the Southern Hemisphere." Xingyu thought for a while and then continued: "Ever since I saw the murderer's inflatable boat, I felt that there was a problem. The inflatable boat is lighter than us and the rafting is faster than us. And we are all in the same direction of the current, and after the inflatable boat drifts away, it is impossible to float back. Seeing the worry on Xingyu's face, Miya didn't interrupt and continued to listen. Xingyu continued: "The currents of the Indian Ocean are like a big disc that flows clockwise for half a year and counterclockwise for the next half year. According to this rule, we start rafting from the Maldai Islands, and we will eventually drift back to the Maldai Islands. But the current is very strange, and for some reason, the current is always changing. It even went against the current, and after a few days it returned to normal. I can't figure out where we drifted like this. When Mia heard this, she couldn't help but interrupt: "No matter where we drift." It stands to reason that now that maritime transport is developed, there must be many cargo ships sailing on the sea. We were supposed to meet a freighter, but we've been adrift for almost three months and haven't seen a single freighter. Xingyu replied with a wry smile: "There are roads on land, and there are also waterways on the sea. Ships usually sail according to the fairway, unless there is a special purpose. Like a survey ship, it will not sail according to the channel. We weren't in the fairway, we didn't see the ship. In fact, it's normal, but it's not normal to see it! Xingyu then asked, "Have you ever heard of the ghost ship?" Without thinking about it, Mia immediately said, "Ghost ship? Is there really a ghost ship in the world? Xingyu had already guessed that Miya would say this, smiled and replied, "That's a scary legend." The real ghost ship is actually a shipwreck. After being shipwrecked, he lost power and drifted at sea. Some ghost ships have been drifting for decades, and the people on board are still drifting even when they die. When one day, when someone came across this ship, which had been wrecked decades ago, they thought it was a ghost ship. In fact, this is just a shipwrecked ship that has drifted off the channel for decades. Mia listened to Xingyu in shock, and then asked with wide eyes, "We may not be able to meet a boat for decades?" Xingyu nodded helplessly.

Although Xingyu has learned sextant positioning, it is now the era of satellite positioning. Xingyu's knowledge of the sextant has long been returned to the teacher. Xingyu originally wanted to guess the approximate direction by relying on the ocean current. But finding that the ocean current was unstable, Xingyu had long lost his bearings. Now I don't have a clue where to go. The Indian Ocean is bordered by Southeast Asia to the east, Africa to the west, India to the north, and Antarctica to the south after passing the equator. It is impossible to be cold in the east, west and north of the Indian Ocean. Now they feel that it is cold, and the only explanation is that they are drifting towards Antarctica. Mia, who was already shocked, now opened her mouth even wider: "Antarctica!" If we drift to the South Pole like this, we will definitely die! Xingyu said with a dejected face: "I hope I guessed wrong." ”

Antarctica, a region that has not yet been conquered by humans, has a colder climate than the Arctic. Although we know that there are abundant natural resources under Antarctica, no country can exploit them. Until now, Antarctica has been uninhabited. There are currently only a few observatories, and a handful of scientists are exploring Antarctica. So it is difficult for them to encounter rescue when they drift to Antarctica. The speculation silenced both of them.

After a long time, Mia suddenly thought of a movie she had seen before. Mia immediately said: "I have seen a movie before, and I can tell from the whirlpool on the washbasin outlet that it is the southern hemisphere or the northern hemisphere. After Xingyu heard this, he immediately widened his eyes and remembered this method: "That's right! This is the easiest way to know if you are in the Southern or Northern Hemisphere. ”

This method, known as the Coriolis effect, uses the deflection force generated by the Earth's rotation to infer whether it is in the Southern or Northern Hemisphere. When the washbasin is filled with water, remove the rubber plug from the downspout. If, unaffected by other factors, the direction of the flow of water in the basin is in a good direction, it is the Northern Hemisphere. If it's against the clock, it's the Southern Hemisphere.

Xingyu immediately picked up the plastic quilt and ran to the lifeboat. Mia also wanted to go out, but just ran to the door and ran back. Mia finds the shoes of the two. After putting on his shoes, he ran out and handed them to Xingyu with Xingyu's shoes. Xingyu rolled the plastic quilt into a funnel shape and tightened the bottom by hand. Then ask Mia to pour the water into the funnel, and then Heungwoo slightly loosens the bottom of the funnel that he is holding tightly to let the water leak out. When water leaks, whirlpools are created. The two tried several times, and the direction of the water was counterclockwise. The direction of the water flow shows them in the Southern Hemisphere. Seeing such an answer, the two looked at each other silently, worried about their future.

After the two looked at each other wordlessly for a while, Xingyu suddenly broke the silence and shouted: "I don't want to be a virgin when I die!" Mia immediately picked up the bucket and made a gesture to splash the ice water in the bucket, and the frightened Xingyu immediately fled.