Dead on Mars

Chapter 130: Sol Two Hundred and Seventy-Two, Visitor From Beyond the Sky

“Comet?” Tang Yue was taken aback.

Mai Dong was installing the C1002 conducting wire when she heard Tomcat’s words. She looked up and said, “A comet, like Halley’s Comet?’

“Yes, that’s it,” Tomcat replied. “But it’s not Halley’s Comet, it’s a brand new one. There aren’t any historical records of it. It’s an aperiodic comet, and its orbit isn’t an ellipse but two curves.”

“When did you discover it?” Tang Yue was surprised.

“Just. I just confirmed its existence.” Tomcat listed the observational data on a monitor. This star has increased seven times in magnitude over the past forty-eight hours, going from a magnitude of 6 to 4. I originally thought it was a variable star, but I later discovered that it was a celestial body within the Solar System. It’s rapidly approaching the sun at increasingly high speeds.”

“Does this mean that we can see a comet?” Mai Dong was pleasantly surprised.

“What does this mean for us?” Tang Yue’s reaction was tense. The first thing that came to mind was of a comet hitting Earth. “There won’t be any danger, right?”

“It’s unknown or the moment. I’ve activated the survey telescope and plan on tracking it. I’ll soon be able to estimate it’s trajectory,” Tomcat replied. “Based on the present results, it’s a comet that has never visited the Solar System. It likely originates from the Oort Cloud…”

“Who cares where it comes from. As long as it doesn’t come to Mars,” Tang Yue quipped.

“Will I be able to see it?” Mai Dong asked.

“Yes, Miss Mai Dong,” Tomcat said. “However, it’s brightness isn’t higher than most of the stars in space. But with the passage of time, it will narrow the distance with the sun, and the comet’s apparent magnitude will continue rising.”

Mai Dong straightened her body as she looked around. The constellations that filled the sky emitted resplendent light but she couldn’t find the broom-shaped star that she imagined.

“But I can’t find it. Aren’t comets like a big broom?”

“It’s still not close enough to the sun, so the comet’s tail isn’t obvious. But it won’t be long before you will be able to find it. It’s a rare comet. Its head should exceed 280,000 kilometers in diameter,” Tomcat said. “Do you know what this means in terms of size?”

Mai Dong shook her head.

“Jupiter’s diameter is only about 140,000 kilometers, so its diameter is twice that of Jupiter,” Tomcat explained. “When Tomcat-Tang-Mai I is at perihelion, it will become the brightest star in the sky. It will also drag out a massive comet tail more than a hundred million kilometers long, sweeping across the entire night sky.

“Wait, what did you just say? What’s Tomcat-Tang-Mai?” Tang Yue frowned. Tomcat often didn’t speak human.

“That the comet’s name,” Tomcat answered.

“You previously mentioned that it’s an unrecorded comet.”

“Yes, that’s why I’ve just given it its name.” Tomcat nodded. “According to the International Astronomical Union, a new comet is given the name of its discoverers.”

Tang Yue ruminated the name a few times before realizing that Tomcat was using their names to name the comet.

Comet Tomcat-Tang-Mai I.

This was probably the last comet to be discovered and named in human history.

“How long will it take before you can confirm its trajectory?” Tang Yue asked.

“The space station’s telescope is tracking it. It will be able to estimate the outcome in a few days. At present, it can be confirmed that the comet will enter Earth’s original orbit, which also means that it will pass by Mars’s orbit. However, it’s still unknown if it will brush past Mars,” Tomcat answered. “However, you don’t have to worry about this problem. Even though the comet appears like a massive, terrifying celestial body, 99% of it is made of thin gas. The real solid comet nucleus is only a few dozen kilometers in diameter.”

“So that means it’s impossible for it to hit Mars?” Tang Yue asked.

“Impossible. The speed of the comet is too high. It far exceeds the escape velocity of any planet in the Solar System. Unless Tomcat-Tang-Mai plunges straight into the Roche limit between the two bodies and gets ripped apart by the tidal forces, Mars won’t be able to capture it.” Tomcat shook its head.

“We can do a simple calculation. The comet’s nucleus is mainly made up of water. Its density is very close to ice, and Mars’s average density is very low. It’s about 4g/cm³. According to the Roche limit’s equation, d = 2.44R³√(ρM/ρm), one can derive the Roche limit to be 7,004 km.

“That also means that the comet needs to approach within 3600 kilometers of Mars’s surface to not be ripped into shreds before smashing into Mars… I’m telling you this, not to keep you on the edges of your seats, but to tell you to remember to watch the show when the time comes,” Tomcat continued. “The comet might be the brightest celestial object of this century. It’s a very rare astronomical wonder.”

Tang Yue heaved a sigh of relief.

He’d rather not see any astronomical wonder than have anything unexpected happen.

Anyone would feel horrified to have Tomcat suddenly tell them that a celestial body was rushing towards Mars’s orbit at nearly 80 km/s.

But in Mai Dong’s eyes, it was a very romantic matter.

However, to Tang Yue, it was like an alert of a nuclear strike.

“As long as Comet Shoemaker-Levy 9’s incident isn’t replicated. Tomcat, you have to know that humans are fearful of celestial bodies. After all, our ancestors were the creatures that survived from a celestial nuclear strike. If it wasn’t that meteorite that produced the Chicxulub crater in Mexico 65 million years ago, I might have a reptilian face now,” Tang Yue said. “I don’t really care about wonders since I’ve already witnessed the disappearance of Earth. What else can still alarm me?”

“It was Jupiter that ripped apart Shoemaker,” Tomcat said. “Compared to Jupiter, Mars is still far from that.”

“Why would there be a comet all of a sudden?” Mai Dong screwed on the screw and asked.

“It’s not sudden. It’s because we just discovered it,” Tomcat replied. “When it passed by Neptune’s and Uranus’s orbit, it didn’t reflect any light due to its distance. It was why we didn’t see it. In fact, it had long entered the Solar System.”

“Will it ever come back again?”

“No,” Tomcat said. “It’s a wandering comet. It will never return after it leaves. In fact, most comets are like that. They wander around everywhere, getting pulled in by the sun’s gravity, circle around it, and leave, never to return.”

“Wandering… Wandering,” Mai Dong whispered as she screwed in the last screw, installing the C1002 wire. “Where do you come from? And where do you belong?”

She looked into the distance again, attempting to find the wandering celestial body that had barged into the Solar System.

But just as Tomcat said, the comet was still too dim. It was like a drop of water that was hidden in the massive sea of stars.

It was an ancient starry sky.

The youngest light that landed in the girl’s eyes was four-years-old.