There are a lot of things to do today, and I took the time to update, so please understand, thank you.

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[Why can humans discover celestial bodies tens of billions of light-years away, but not find the ninth planet?] 】

Scientists can already detect a galaxy millions of light-years away, or even beyond, but why are they still so slow to determine the existence of Planet 9?

Speaking of which, let's talk about the current discovery of the eight planets.

First of all, the six planets on the inner side (water, gold, fire, earth, and earth) were already known to people long before the invention of telescopes, and they are "prehistoric" discoveries......

On March 13, 1781, William Herschel, a British astronomer who loved astronomy, discovered an unknown celestial object while observing the night sky with his telescope. He initially thought it was a comet, but after repeated confirmations, he found that it was a planet. Since then, Uranus has become the first planet to be discovered on record.

The discovery of Uranus was a coincidental discovery, or a widely observed discovery (I made up my own name).

After the discovery of Uranus, scientists calculated its orbit and found that Uranus's orbit was very abnormal and did not conform to the known laws of physics.

Later, some scientists speculated that this was due to the fact that there is a huge planet outside Uranus, whose gravity affects the orbit of Uranus.

Using data on Uranus' orbital differences, two scholars, Auburn Le Verier and John Cauchy Adams, calculated the potential planet's orbit almost simultaneously and contacted local observatories to make observations. As a result, they discovered a new planet, which is Neptune.

The discovery of Neptune is a computational discovery, so it is also called "the planet on the tip of the pen".

However, scientists found that even after the addition of Neptune, the orbit of Uranus still did not conform to the original laws, and even Neptune was a little off, so they continued to speculate that there were other celestial bodies at play.

This time, they weren't so lucky. Even after repeated calculations, no new objects have been discovered.

It wasn't until 1930 that Clyde Tombaugh discovered a new celestial body, Pluto, and the solar system has since had eight planets.

Speaking of which, the discovery of Pluto is also a widely observational discovery.

In 1992, scientists discovered a new celestial object outside Pluto, Eris. Since Eris is almost the same size as Pluto, some scientists believe that it should be a planet. However, because it is relatively small, many scientists have made claims that it is a planet, and by the way, even Pluto's planetary status has been questioned.

In 2006, the International Astronomical Association finally truly defined the concept of planets in words. Since neither Eris nor Pluto fit the definition of a planet, they are excluded from the ranks of planets. The solar system has returned to the state of eight planets, and scientists have begun to search for the ninth planet again.

A few years ago, an astronomical team said that it was suspected that a large planet had been discovered, which was very far away from the sun and even larger than Jupiter. They named it Xingshen, and they also made mankind full of anticipation for the discovery of new planets.

However, after years of observation, NASA finally regretfully announced that they had not found any trace of Lucky God, and the planet probably did not exist.

If it existed, it should have been discovered (in whatever form of detection).

The hypothesis of Planet Nine stems from the unknown gravitational influence of extraneptune objects.

If Planet Nine does exist, then its gravitational effects will be our preferred target for exploration. This is similar to the discovery of Neptune, when scientists discovered something unusual about Uranus' orbit and hypothesized a planet eight. Not only did they assume the existence of Planet 8, but they also calculated its position based on the anomalous orbit of Uranus. The astronomers pointed the telescopes at the calculated position and discovered Neptune!

It is much more difficult to verify the existence of Planet 9 in this way. Its gravitational pull affects many small celestial bodies whose orbits are irregular and elusive. No trace of Planet 9 has been found anywhere that has been explored, but we have another answer: Planet 9 does not exist at all!

This is a good explanation for why we have been slow to discover it, after all, how can we verify something that doesn't exist at all? Just like Vulcan, after astronomers discovered Neptune and observed an anomaly in Mercury's orbit, they hypothesized a Vulcan to explain the strange phenomenon. When the astronomers pointed their telescopes at that theoretical location, they saw nothing.

There is now a plausible explanation for the anomaly in Mercury's orbit: Mercury's orbit is so close to the Sun that the effects of general relativity are beginning to manifest. I don't think that the discovery of Planet Nine will change the existing laws of mechanics dramatically, but it will drive astronomers to look for new theories to explain this strange phenomenon at the edge of the solar system, even if there are many of them.

Whether or not we find Planet 9 in the end, the process will be very interesting and will change our understanding of the solar system.

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