Chapter 2859 Hagrid's Holiday (9)

The reason why the Cepheid variable star is called this name is that John Goodley discovered δ Cepheus in 1784. Its visual star magnitude is 3.7 at its brightest, 4.4 at its darkest, and its photoperiod is 5.37 days.

This regularly changing brightness star can be regarded as a "heartbeat". Cepheid is a double star. Its primary star is a yellow supergiant or bright giant star, and its companion star is blue-white. Since the difference between the two is not large, and their Neither is massive enough to go supernova, so it should eventually shrink into a white dwarf.

There is a bright reflection nebula in Cepheus, known as the Iris Nebula. If the weather is good, you can observe it with a large-aperture telescope. It is the dust produced by a supernova explosion. The reason why it can be seen is It is sometimes nicknamed the "Iris Nebula" because there is a star nearby and the dust reflects light, making it visible blue like an iris.

Not every nebula is a galaxy, and even if the center of the Iris Nebula glows red, it's not a star, it's just matter in the dusty center that has changed under ultraviolet light.

This is the most splendid "firework" in the universe, although it means the death of a massive star.

Cepheid, like many yellow giant stars, starts to burn helium after burning hydrogen, but at this time it cannot produce matter heavier than helium like a red giant star. A helium ionosphere will be formed inside the star, allowing the ionized helium to continue to burn. ionization. At the beginning, the yellow giant star will expand, because of the gravitational contraction, the secondary ionized helium will become the primary ionized helium, and release heat outwards. With the accumulation of radiation pressure, it will eventually exceed the gravitational force, continue to expand as before, and then Because of gravitational contraction, this cycle continues until the helium burns out and shrinks into a white dwarf.

In ancient Greek mythology, Poseidon's wife was very angry because her mother, Cassiopeia, kept showing off her beauty. She asked Poseidon to "revenge" her. The Immortal King asked the oracle, and the oracle revealed that the way to rescue was to sacrifice Andromeda, the daughter of the Immortal King and Cassiopeia.

She was locked by her parents on the only way of Cetus, and was seen by the hero Perseus, so Perseus immediately took out the head of Medusa, the Gorgon, and petrified Cetus, and Perseus rescued her. her.

"Medusa's Eye" is located in Perseus. It is also a variable star in a binary system, but it is different from Cepheid. It has a companion star that is much dimmer than the main star. When the companion star circles between the observer and the main star , a star eclipse will be formed, covering the main star and dimming the "Eye of Medusa" for about 10 hours. After the eclipse is over, the brightness will resume again.

Therefore, the "Eye of Medusa" in Perseus cannot become a "candlelight" and become a measuring stick, because it is not a member of the Cepheid variable star family.

The large and small Magellanic clouds cannot be seen in the northern hemisphere, but they are the most spectacular landscape in the southern hemisphere, and they are also the objects that astronomers have been chasing. Charles Pickering, who just took over the Observatory of Harvard University, entrusted his younger brother William Pickering to Peru to establish An observatory was built and a large number of photos of the Magellanic Clouds were taken, so that Charles Pickering could obtain photos of the starry sky in both the northern and southern hemispheres.

But with the photos and technology at that time, it was impossible to take pictures of the magnificent starry sky. There were only two colors of black and white, which looked like white spots that could not be wiped clean on a blackboard.

Pickering hired a special person to classify these stars, but men are simply not capable of such a boring, repetitive, patient and careful work. Charles soon found that the male staff he hired could not compare with his maid, so he Simply hired a group of women to deal with the accumulation of more and more photos.

At the beginning of the 20th century, women's status was extremely low, and there were few jobs they could do, especially in the intellectual circles. Pickering ruled out the difficulties and formed such an all-female team. They were nicknamed "Pickering's Harem" ".

After getting the opportunity, they went all out to process the photos of the starry sky from the northern and southern hemispheres that they had accumulated for a long time. In addition to stars, there are also new stars and supernovae that suddenly appeared and then disappeared suddenly. This is the main material that Pickering needs.

Deaf and dumb Henrietta, despite her high education, was unable to communicate with the rest of the team, and she was sickly and would suddenly be unable to work, and Pickering arranged for her to deal with the dispensable variable star.

But it was also because she couldn't hear the noisy voices in the office that she could concentrate on discovering this small detail.

Women include all women over the age of 14, not just young and beautiful "goddesses". Maybe there are 15 year old "women" who think, "How can I be one of those fat old housewives?"

Now let this beautiful "goddess" sit down, let's talk about the gravitational lens, the Einstein ring, and then talk about the celestial ball.

Gravitational lensing is due to the fact that massive objects can bend space-time, and the curved space-time can be equivalent to a lens, which has the effect of a magnifying glass and allows humans to see farther starry sky.

Wizards can bend time and space, and Apparation is similar to a "wormhole", although it is not as far away as the neighboring star that can be shuttled.

Priya Moore's work in the Department of Mysteries is space, although it seems to be studying planets, and it is also a solar system.

When Ben Cooper went to get the Time Converter that day, her "former colleague" asked her about her situation. Gen wouldn't be so angry, and sent her to the centaur's office at once.

It is more sad not to have the opportunity to work hard than to fail to succeed through hard work. At least those Flobber caterpillars are still fed. What do they eat if they don’t work?

But if Henrietta were to spin yarn like a female worker in a textile factory, would there still be this great discovery in astronomy, and even change human cognition?

Albus used to care about what Hagrid was doing and what new magical animals he bred during the summer vacation, but he has been "playing" with Severus recently.

Pomona ignored the flying dragonflies, but Severus went after them, and he discovered a new chamber.

It was just behind the stone dragon statue, covered by a tapestry, how he found and got in she didn't know, but he and Dumbledore were "killing time" there anyway.

Now Pomona was looking for dragonflies, but couldn't find any, as if they were all hiding.

That being the case, she went to the Forbidden Forest, there was nothing to stay in the castle anyway, and a dangerous "beast" lurked.

In the era of Principal Moore, there had been no incidents of Muggle-born being attacked and killed. It didn’t matter if she released the ingenious key for the students to chase, but it would be very risky to do so now.

Maybe she should catch all the dragonflies in the castle before school starts.

Fortunately, Hagrid didn't care about continuing to make Flobber caterpillars "useful". He was training Fluffy, the three-headed hell dog that Carter gave him, not to take food from the mouths of other heads.

His progress didn't seem to be very good. Anyway, Pomona saw that the middle head often competed with the left and right heads, and the left and right heads couldn't fight because they were separated by the middle head.

Everyone has something to play, but she seems to be the only one who doesn't. Fortunately, Liz's owl Artemis sent the lace dress she wanted.

Only the nightdress was made to Professor Sprout's figure and looked like a fishnet.

She is not good at manual work, although she can do magic, but magic cannot solve all problems.

She had to find someone to change it, or she had to learn it by herself... Then she remembered Molly, who seemed to have not been to the Weasleys for a long time.

It just so happened that Bill's owls test results came out, but the report card was not sent out. He got 12 o's, the same as Barty Crouch Jr.'s.

It seems that she should give him a gift, what should I give him? Maybe she could sponsor him to go to Brazil as an exchange student, but then, who would Severus ask for the next year's Potions Competition?

"Never mind it." Pomona put away the "fishnet", hoping that Molly wouldn't misunderstand, she just wore it for the hot weather, and there was no other meaning, even though the clerk's expression when he introduced those lace pajamas It doesn't look right.