"Comet?" Tang Yue was stunned.

Mai Dong was installing line C1002 when he heard what the old cat said, and raised his head, "Is it the comet of Halley's Comet?" ”

"Yes, it's the broom star." The old cat replied, "But not Halley's Comet, this is a new comet, there is no record of it in history, it is a non-periodic comet, the orbit is not elliptical but hyperbola." ”

"When did you find out?" Tang Yue was a little surprised.

"Just now, I just confirmed its existence." "Because this star has brightened sevenfold in the last forty-eight hours, and the apparent magnitude has suddenly increased from sixth to fourth, I thought it was a variable star, but then I found out that it was a celestial body in the solar system, and the rapid increase in brightness is because it is approaching the sun at high speed." ”

"So we can see the comet?" Mai Dong surprise.

"What does this mean?" Tang Yue's reaction was very nervous, he immediately thought of the drama of the asteroid hitting the earth, "There won't be any danger, right?" ”

"For the time being, the situation is unclear, but I have turned on the survey telescope on the space station, ready to track it, and soon be able to predict its orbit." The old cat replied, "Judging by the results so far, this is a comet that has never been to the solar system, and its source may be the Oort cloud ......"

"It doesn't matter where it came from, as long as it doesn't come to Mars." Tang Yue muttered.

"Can I see it?" Mai Dong asked.

"Yes, Miss Mai Dong." "But it's not brighter than most stars in the night sky now, but as time goes on, the comet's apparent magnitude will continue to increase as it gets closer to the sun." ”

Mai Dong straightened up and looked around, the stars in the sky were shining brightly, and she couldn't find the broom-like comet she imagined.

"But I can't find it, isn't the comet a big broom?"

"It's not close enough to the Sun to have a clear tail, but it won't take long for you to find it, it's a rare big comet, and its head should be more than 280,000 kilometers in diameter." The old cat said, "Do you know what this size is?" ”

Mai Dong shook his head.

"Jupiter is only 140,000 kilometers in diameter, and it is twice the diameter of Jupiter." "When Comet Tomcat-Tang-Mai No. 1 is closest to the Sun, it will become the brightest star in the whole day, and it will drag a huge tail hundreds of millions of kilometers long across the entire night sky. ”

"Wait, wait, what did you just say? What is Tomcat-Tang-Mai? Tang Yue frowned, the old cat often didn't spit out words in his mouth.

"The name of the comet." The old cat replied.

"You said earlier that this was a new comet that had no record."

"yes, so I just got the name." The old cat nodded, "According to the regulations of the International Astronomical Union, comets are named by the discoverer. ”

Tang Yue took the name in his mouth and chewed it several times before realizing that the old cat was named after their names.

Comet Old Cat-Don-Mai I.

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

"How long will it take you to confirm its orbit?" Tang Yue asked.

"The space station's telescope is tracking, and the prediction results will be available in a few days, and what can be confirmed at present is that the comet will definitely enter the original Earth orbit, which means that it will pass through the orbit of Mars, but I don't know if it will pass by Mars." The old cat replied, "But you don't have to worry about what will go wrong, although the comet is a terrifyingly large celestial body, it is composed of 99 percent of the thin gas, and the real solid nucleus is only a few tens of kilometers in diameter." ”

"So it's impossible for it to hit Mars?" Tang Yue asked.

"Impossible, the comet is flying too high, far beyond the speed of the detachment of all the planets in the solar system, and Mars has no ability to capture it unless Comet Tomcat-Tang-Mai plunges headlong into the Loch limit of both and is directly torn apart by tidal forces." The old cat shook his head.

"We can do a simple calculation, the main component of the Hui core is water, then its density is similar to ice, the average density of Mars is very low, about four grams per cubic centimeter, according to the formula for calculating the fluid Loch limit d = 2.44R3√(ρM/ρm), the result can be 7004 kilometers."

In other words, the comet would have to be at least as close to the surface of Mars as it would be within 3,600 kilometers before it could be torn to pieces and smashed into the surface of Mars...... I am telling you this news not to make you afraid, but to tell you to watch it when the time comes. "This comet has the potential to become the brightest object of this century, and it is a rare astronomical spectacle." ”

Tang Yue breathed a sigh of relief.

He would rather not look at this astronomical wonder of Rauschzi than have any side effects.

The old cat suddenly told him that at this time, a celestial body was rushing towards the orbit of Mars at a high speed of seventy or eighty kilometers per second.

In Mai Dong's eyes, this matter is very romantic.

But in Tang Yue's view, this is simply a nuclear strike alarm.

"As long as it doesn't happen like Shoemaker Levy 9, you must know that humans are naturally afraid of such celestial bodies, after all, our ancestors were creatures who survived this space nuclear attack, and if it weren't for the asteroid that fell into the Gulf of Mexico 65 million years ago, I might have a lizard face right now." Tang Yue said, "I don't care about the spectacle or anything, I've seen the wonder of the earth disappearing, what else can surprise me?" ”

"It was Jupiter who tore Shoemaker apart." The old cat said, "Compared to Jupiter, Mars is too far away." ”

"Why did a comet suddenly come at this time?" Mai Dong screwed the screws and asked.

"It's not out of the blue, it's just that we just found out." The old cat replied, "When it crossed the orbit of Neptune Uranus, it barely emitted light because it was so far away that we couldn't observe it, and in fact it had already entered the solar system." ”

"Will it come back in the future?"

"No, it won't." The old cat said, "This is a wandering comet, and after leaving, it will not come back, in fact most comets are like this, drifting around, being pulled by the gravitational pull of the sun, turning around and walking away, never coming back." ”

"Wandering...... Stray. Mai Dong whispered, screwed the last screw, and installed the C1002 line, "Where did you come from?" Where is the way home? ”

She looked around again, trying to find the wandering object that had broken into the solar system.

But as the old cat said, the comet was still too bright at this time, and it was hidden like a drop of water in the endless sea of stars.

It's an ancient starry sky.

The youngest light that fell into the eyes of the girls came four years ago.