What Chen Muwu told Eddington was to calculate the distance of Andromeda from the center of the Milky Way by observing the Cepheids in the Andromeda Nebula.
As long as we can measure this distance and compare it with the known radius of the Milky Way, we can know whether Andromeda is a nebula included in the Milky Way, or whether it is outside the Milky Way and is a galaxy with the same status as the Milky Way.
This method of using Cepheids to measure distances was first proposed by American astronomer Harold Shapley.
Using this method, he estimated the radius of the Milky Way in 1918 and was the first to point out that the sun is not located at the center of the Milky Way.
However, Shapley is a loyal supporter of the theory of the only galaxy. He believes that the universe is the Milky Way, and there are no other galaxies of equal status outside the Milky Way.
Edwin Hubble was inspired by Shapley's method. He began to observe nebulae such as Andromeda at the Welsh Mountain Observatory, hoping to find Cepheids and calculate their distances.
Hubble published a large amount of observational data at the end of 1924, confirming that several "nebulae", including Andromeda, are actually outside the Milky Way.
This proves the error of Shapley's theory. Nebulae should not be called nebulae, but should be called galaxies.
The astronomical problem Chen Muwu mentioned was that he wanted Eddington to first measure the distances of these nebulae from the Milky Way for future reference.
As for what this back picture is?
Of course, it was proved that the universe is expanding by discovering the red shift, and then overturning the static universe model proposed by Einstein!
Unexpectedly, after Eddington heard what Chen Muwu said, he just smiled bitterly twice, then stood up and nodded to Chen Muwu on the sofa: "Come on, Chen, come with me."
The two walked out of the office one after another. Eddington led Chen Muwu to the dome of the Cambridge Observatory, pointed to a refracting telescope mounted on a bracket and said: "Chen, this is the largest telescope in our observatory. It was donated in 1833 by the 3rd Earl of Northumberland, who later became Chancellor of Cambridge University.
"Yes, you heard it right, 1833, exactly ninety years ago.
“This twelve-inch telescope was indeed a big thing at that time, but today, ninety years later, it is far behind the times.
"The method you mentioned about Shapley's method of calculating distances from Cepheids, I actually knew it a few years ago. But what's the use of knowing it? When Shapley observed Cepheid variables, the diameter of the telescope he used was , already sixty inches.
"I heard that not long ago, Mount Wilson Observatory built a new one-hundred-inch telescope. The United States has a lot of money, so of course there is plenty of money to build telescopes.
“But we at Cambridge University have no money. Our observatory’s annual funding is basically only enough to maintain this ninety-year-old thing.
"Not to mention compared with the two behemoths above, even the wealthy American guy in Lowell spent money to build the telescope in the observatory in order to find the mysterious Planet X hidden in the dark. The Sumberland is twice as big!"
Eddington's hand gently touched the old machine on the shelf, with a deep helpless tone in his words.
What he said was very clear, and Chen Muwu also knew it. It seems that using the telescope at the Cambridge Observatory, it is impossible to measure the brightness of the Cepheid variable stars in Andromeda, which means that the distance cannot be calculated. .
His idea was now in vain.
Only after Hubble publishes its observational data next year can Chen Muwu, based on his data and the red-shift spectral lines of Vesto Sriver, point out that the universe does not remain static but is constantly expanding.
Somehow, God couldn't bear to let Eddington break Einstein's dream.
However, Chen Muwu also discovered another useful information from Eddington's words.
Isn't the Planet X he's talking about Pluto?
Historically, Pluto was discovered in 1930.
Since the discovery of Neptune, people have been speculating that there should be a planet in the solar system beyond Neptune.
Because we have been looking for it for sixty or seventy years but have not found it, now this planet that people love and hate but cannot find has been given the same name as the Roentgen rays, called Planet X.
But for Chen Muwu, this is really "the world and the earth are united in time". The great discoveries in physics are coming to his door one after another, and he can't even think about it.
One summer night in his childhood, while enjoying the cool air with his parents outdoors, Chen Muwu inadvertently looked up and saw the Summer Triangle.
Since then he has been interested in astronomy, which to some extent was one of the reasons why he chose physics after finishing the college entrance examination.
Although he later embarked on a path that had nothing to do with astronomy, he was always a member of the astronomy club during his college years. During his undergraduate period, he also served as a voluntary lecturer at the local planetarium for four years.
As an astronomy enthusiast, Chen Muwu can remember that the semi-major axis of Pluto's orbit is 39.482 astronomical units, the eccentricity is 0.2488, the mean periapsis angle is 14.53 degrees, the orbital inclination is 17.16 degrees, the ascending node celestial longitude is 110.299 degrees, and the perihelion angle is 110.299 degrees. The argument angle is 113.834 degrees, etc. These data are also normal, right?
But he doesn't want to take this data and find Pluto in the telescope right now.
Because now, Chen Muwu is still a newcomer who has never conducted astronomical observations. China is also a poor country that does not even have a modern observatory.
The observatory on the Purple Mountain in Tingjing will not be completed until more than ten years.
If he found Planet
Just like criminals launder money, if Chen Muwu wants to successfully "discover" Planet X, his astronomy skills must be completely whitewashed.
So he pretended to be longing for the stars and the sea: "Sir, I am also very interested in this planet X. From today on, can I come to your place every few days and borrow this telescope for astronomy?" Observation?”
"How long is a few days? Half a year?"
Eddington obviously had not forgotten the fact that Chen Muwu let him go, but seeing that he had the intention of breaking away from Cavendish and returning to the embrace of astronomy, Eddington finally nodded and agreed to the matter.
He asked Chen Muwu if he had ever conducted astronomical observations before. Chen Muwu said that he had only read some astronomy books, but had never actually operated a large instrument.
After receiving this answer, Eddington asked Chen Muwu to compile a literature reading report on Planet
After this series of procedures are completed, the refracting telescope behind him can be used by Chen Muwu every Sunday evening, but he must be contacted in advance before every Friday to confirm.
"Okay, thank you sir."
At this point, the last stone in Chen Muwu's heart was relieved.
The apparent magnitude of Pluto is about fourteen, and a telescope that can observe the brightness of this magnitude must have a diameter of at least two hundred and fifty millimeters, which is about ten inches when converted to hateful imperial units.
The 90-year-old Northumberland Telescope is the only astronomical telescope over ten inches in the Cambridge University Observatory.
If Eddington had not nodded and agreed to let him use this large telescope, but only provided him with a small telescope, then even if Chen Muwu looked at the stars and his eyes were split, he would not be able to find the star hidden in the darkness. Planet X in .
After deciding on this series of matters, it was already time for dinner. Eddington invited Chen Muwu to attend a dinner with complicated etiquette in the auditorium of Trinity College.
Chen Muwu readily agreed to the invitation, but the two people at the astronomical telescope seemed to have forgotten that there was Dirac sitting on the sofa in Eddington's office next to the dome!
(End of chapter)
