Pluto, 5 facts that have been found in one year since the exploration, Japanese version of the Japanese version of the Japanese version

　Since the discovery in 1930, humankind has been fascinated by the hundreds of kilometers of Pluto.

　One year ago, on July 14, 2015, NASA's unmanned spacecraft New Horizons succeeded in approaching Pluto, and we decided to see it for the first time.

　小さな冥王星の横を探査機が通過するのに要した時間はわずか3分だったが、冥王星と、その巨大な衛星カロン、4つの小さな衛星ステュクス、ニクス、ヒドラ、ケルベロスを擁する冥王星系全体は、もっと長く、じっくりと観察することができた。（参考記事：「冥王星“接近通過”をめぐる10の疑問に答える」）

　The data collected at that time is still surprising and confused the scientists, but Pluto has become a very popular person in the streets, and the title was made in the United States in 1991 with the title, "Pluto is unbody."The stamp was published as "Pluto has been explored".

　ニューホライズンズからのデータ送信はまだ続いているが、科学者たちがこれまでに明らかにした、驚きの事実のほんの一部をご紹介しよう。（参考記事：「冥王星に信じがたい5つの新事実発覚」）

Pluto is alive

　Pluto has a strange terrain in the solar system, including the vast plains with methane ice covered with a snake scale.However, in the basement, geological activities are also occurring that overturns the concept of ice celestial bodies.

　Until then, scientists have thought that there is almost no geological activity in this frigid celestial body at the end of the solar system.

　It has been pointed out that ice has been moving on the surface of Pluto every season on the surface of Pluto, but the data of New Horizons has revealed unexpected facts.Pluto is still "alive" (or until just recently).It is said that the substance on the surface is moving due to the effect of internal heat.

　Mr. Kathy Olkin of the Southwest Research Institute in the United States mentions the sputnik plains, which is about 1200 km in diameter, and said, "It was really surprising that Pluto was so far away from the sun."。

　なめらかなその平原は多角形のパターンに分割されている。それはすなわち、新しい氷が下からゆっくりわき上がってくることを示している。その表面の氷は地質学的に驚くほど新しいもので、50万～100万年ほどで置き換わるという。（参考記事：「冥王星、氷が絶えずわき上がる意外な地質運動が判明」）

　According to Oliver White of the U.S. Aeronautics and Space Agency (NASA) Aims Research Center, "I thought there would be an activity related to the interaction between the surface and the atmosphere when Pluto would be around the sun.I was surprised that the nitrogen ice lumps were pronated over a wide area! "

Glacier with nitrogen glaciers

　A glacier made of frozen ice is flowing into the Sputnik Plain, and its movement is similar to the glacier of the earth.The plain has a huge iceberg made of water frozen, but the glacier of nitrogen carries a fragment of ice by flowing the iceberg of the water and has a groove on the surface of Pluto.

　Although the liquid may have a groove on the surface, Mr. Will Grandi, the US Lowwell Observatory, says he has no idea.It is a mystery whether there is a sea under the Pluto basement.

　Another mystery is the light and Mt. Picard with a depression on the top.It is thought that both are huge ice volcanoes, which are not burning lava, but are gushing out nitrogen, carbon monoxide, or water ice.

　"When you see something up close, you can find much more mystery than the answer," says Grandy."At least this time this time."

Caron is not dead

　It seems that Pluto's achievement alone was a great success, but not only Pluto has seen New Horizons.

　Pluto's huge satellite Caron was also found to be a wonderful and strange celestial body.Calon, which is considered to be a double astronomy with Pluto, was not a dead celestial body full of crater as expected by many scientists.

"I thought Caron was a boring gray astronomical object full of craters like Saturn's satellite rare, but it was too sweet," said Curly Haetto of the Southwest Research Institute.Say.

　確かにカロンにもクレーターはあり、その数は冥王星より多かったが、予想を下回るものだった。カロンは冥王星に比べて全体的に黒っぽく、その極地方には謎めいた暗赤色の領域があり、「モルドール・マキュラ」と呼ばれている（モルドールは、トールキンの小説『指輪物語』に登場する冥王サウロンの王国で、『黒の国』という意味）。この領域は、冥王星から飛んできた分子が堆積して色がついたと考えられている。（参考記事：「冥王星の衛星カロンに謎の黒い領域」）

　Caron also has a deep crack.Scientists have not yet been able to explain the reason, but the underground sea may have frozen and expanded, tearing the surface.Like Pluto, the surface of the caron is surprisingly smooth and still geologically new.

"Perhaps it took longer than we expected before the calon was formed and cooled," said Huett."Or, our understanding of the celestial bodies that collided with Karon may not be as new as we thought first."

Satelles around strange orbitals

　Scientists are also looking for hints to understand the formation of the double -heaven system, struggling with the mystery of Caron.At this time, it is thought that it was formed by a huge astronomical collision, just like the moon on the earth.The clues to this collision are not only Pluto and Caron, but also in small satellite Sticks, Nix, Cerberos and Hydra.

　According to Simon Porter from the Southwest Research Institute, the theory that four small satellites had been thrown into outer space during the formation of a caron.

　The problem is that the movement of the four satellites does not match the collision hypothesis.

　"The track of these satellites is more strange than we had thought," said Kelsea Singer of the Southwest Research Institute.

　Some satellites rotate at high speeds without synchronization and move along the inclined trajectory.The color is strange and has a brighter color than Karon.Nix has a reddish crater, and the hydra has a shape like a collision of two debris.

　The small satellite of Pluto can only be seen as a collection of miscellaneous celestial bodies.

　According to Alex Parker of the Southwest Research Institute, "The origin of these satellites was a mystery before the approach of New Horizons, but the observation data we collected only deepened the mystery." To tell.

Pluto atmosphere overturned the hypothesis

　After passing the Pluto system at a fierce speed, New Horizons looked back and photographed the Silhouette of Pluto and Caron.The terrestrial scientists who received the outline of Pluto were remarkable.Pluto behind the sun was wrapped in an eerie blue light circle.

　In addition, the light is divided into many layers, and scientists are currently working on clarification.

　Pluto has a thick atmosphere of nitrogen, which was revealed in 1988 by analyzing distant star light passing through it.However, the fact that the atmosphere is many times that of the earth has been bothering scientists for more than 20 years.Until then, when Pluto moved away from the sun, a hypothesis was made that the atmosphere had frozen and falling on the surface.

　But that was not the case.From the earth, the atmosphere is getting thicker and thicker.

　The observations from the earth have suggested that a large amount of molecules will move out of the gravity of Pluto and go into outer space.

　However, the approach of New Horizons has revealed that the pluto atmosphere was not as thick as expected, but the molecules were rarely appeared.According to Singer, scientists now believe that Pluto's atmosphere is kept at low temperatures due to "unexpected reasons" and relatively stable.

　It may be unreasonable to be questioned by the observed observations that have been accumulated for decades in just a few minutes, but scientists are rather pleased.

　Parker said, "With this approach, the multi -layered structure of Pluto atmosphere and the polygon pattern of the Sputnik Plain, it is clear that Pluto is a natural body that changes dynamically.I said. "However, it is not clear how Pluto changes on a scale."With only a snapshot that cuts out the moment, you have to guess the change of Pluto from there in detail."

Future of Pluto Research

　New Horizons is currently sending Pluto's observation data to the earth, flying toward the next target, Kiperberten (provisionally called 2014 MU69).

　These data may reveal some of the remaining mysteries of Pluto in the next few years.Nevertheless, there will be a mystery that scientists want to send another spacecraft to Pluto, preferably around the trajectory.

　New Horizons showed a wonderful view while approaching Pluto, but only one hemisphere could be recorded at a high resolution, and the remaining hemisphere is still mysterious.

　In the future mission, the history of Pluto's activity has been elucidated, and the first time the solar system was born, when Pluto was closer to the sun, it may be clear.

"What kind of celestial Pluto was at that time?" Said McKinon of Washington University."Is this" old "record on the surface of Pluto? If not, how do you explain the past evidence of abnormally active geological activity?"

　Pluto has become alone, but it is no longer an unknown celestial body.The controversy will continue over Pluto, but it has become clear that Pluto is a much more interesting celestial body than expected, regardless of whether it is called a planet or a quasi -planet.