How far is Pluto from the earth and how was it discovered?

Pluto is no longer a planet, but a dwarf planet. It is the largest dwarf planet with the second largest mass. It is the second celestial body with great contrast in the solar system, second only to Partos. So do you know how far Pluto is from the earth? How did you find out? Let's reveal the constellation knowledge for everyone!

How far is Pluto from the earth? The average distance from Pluto to the sun is close to 40 astronomical units (astronomical units are also the length units used in astronomy, which is equal to the distance from the sun to the earth, that is, 65.438+0.5 billion kilometers). However, due to the great eccentricity of Pluto's orbit around the sun, the distance between perihelion and apohelion is also very different. Pluto's orbit perihelion is 44368246 13km(29.64067 astronomical units) and apogee is 737592793 1km(49.687 astronomical units). When Pluto and the earth are on the same side of the sun and Pluto is at perihelion, the distance between the earth and Pluto is the shortest, which is 29.66- 1 = 28.66 astronomical units. When Pluto and the earth are opposite to the sun, that is, Pluto is on one side of the sun, the earth is on the other side of the sun, and Pluto is at apohelion, the distance between the earth and Pluto is the farthest, which is 49.3+ 1 = 50.3 astronomical units. Again, it takes 15000/30 = 500 seconds for light to travel from the sun to the earth, which is 8 minutes and 20 seconds, or 8.33 minutes, which means 1 astronomical unit = 8.33 light minutes. Then, when Pluto is closest to the Earth, the distance is 8.33× 28.66 = 238.74 light minutes. When Pluto is farthest from the Earth, the distance is 8.33× 50.3 = 4 19 light minute = 6.98 light hours. This is the closest and farthest distance between Pluto and the earth. If light years must be used as the distance unit, 1 light years is about 63240 astronomical units. So: the closest time for the Earth to Pluto is 28.66/63240 = 0.000453 light years. When the earth is farthest from Pluto, it is 50.3/63240 = 0.000795 light years.

How was Pluto discovered? Let's take a brief look at Pluto: Pluto was discovered in 1930. It was once one of the nine planets in the solar system, but was later downgraded to a dwarf planet. Because it is almost 6 million kilometers away from the sun, Pluto is in almost eternal darkness and its orbit is very special. The ancients noticed a long time ago that in addition to the seemingly unchanging sun, there were several dishonest "rovers"-planets. Zhang Heng, an astronomer who invented the seismograph in the Eastern Han Dynasty, once wrote in Lingxian County: "Where literary talent is gorgeous, its movers are seven, and the sun, the moon and the five stars are also there." The "five stars" mentioned here are the familiar planets in the solar system: Mercury, Venus, Mars, Jupiter and Saturn. For most of the long history of mankind, these five planets (after the arrival of "Heliocentrism") and the earth are people's understanding of the solar system family planets. Until 178 1, a German-born British astronomer named William Herschel discovered a light blue new celestial body with a small round surface like a planet. At first he thought it was a comet, but in his circle of astronomers, it was soon pointed out that the orbit of this new celestial body was almost perfect. This is the first time that mankind has discovered the new frontier of the solar system after the "five stars in the sun, moon and moon". This new planet is named "Uranus" after the god in charge of heaven in Greek mythology. In a blink of an eye, more than half a century has passed, and Uranus has been orbiting the sun for almost a week since it was discovered. It is found that the position of Uranus in the sky always seems to be inconsistent with Newton's mechanical prediction-was Newton wrong? People don't think so. In the summer of 1846, British mathematician john adams and French mathematician Auburn Levi published articles almost at the same time, pointing out that the "abnormality" of Uranus' operation should be caused by the gravitational influence of another undiscovered planet nearby. They calculated the possible positions of unknown planets and asked the Observatory to observe and search within the predicted range. Sure enough, it took the New Berlin Observatory only a few months to discover this "planet on the tip of a pen" near the prediction area in September this year-it was named Neptune.

The discovery of Neptune made the image of Newtonian mechanics "great, glorious and correct" more deeply rooted in people's hearts. People can't help but expect that there will be more planets in the solar system waiting for people to discover. More than half a century has passed. At the beginning of the 20th century, a local astronomer, Percival Lowell, thought that Neptune's orbit was different from that predicted. He concluded that besides Neptune, there was an undiscovered "planet X". The local tyrant who first discovered that there was a canal-like ditch on Mars, which triggered the fantasy frenzy of the science fiction literature "Martians", established his own "Lowell Observatory" and began to search carefully. Unfortunately, he never found it until his death. At the same time, another American astronomer, william pickering, predicted the existence of what he called "planet O" beyond Neptune for the same reason. However, he searched with the telescope of Mount Wilson Observatory in the United States and found nothing. Ten years after Lowell's death, Lowell Observatory received a letter from a young man. The author is clyde tombaugh, a 20-year-old farm boy from Kansas, USA. /kloc-dropped out of school at the age of 0/6, and his father worked to make money for him to build telescopes in order to let him continue his astronomical ideal. Tombaugh sent a letter to Lowell Observatory, which is a portrait of the moon and planets observed and described with this homemade telescope. This letter won Tobo a job at Lowell Observatory-following Lowell's wishes, continuing to search for Planet X.. Tang Bo used a telescope with a diameter of 33 cm to photograph all possible positions in the sky, and observed the observation results with a "flash comparator". Under this flash-forward contrast mirror, when switching between two photos taken several days apart in the same sky area, the human eye is not sensitive to fixed stars, but it is easy to find small bright spots with significant changes in positions-they are planets, asteroids, comets and other solar system celestial bodies. 1930 February 18, Tang Bo ushered in the brightest moment in his life: near the zodiac of Gemini, a light spot that moved significantly in a few days caught his attention. After calculation, this is a planet farther than Neptune. Perhaps it is the "Planet X" Lowell is looking for, and it is finally determined to be Pluto.

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