Monumental Discovery

During the next few years, Herschel continued to practice building telescopes. He also began systematically mapping the night sky and recording his findings. He compiled papers on sunspots, variable stars, the geography of the Moon, and the poles of Mars. This was all significant work, but in 1781, Herschel made a monumental discovery.

On the night of March 13, 1781, as Herschel was observing with his favorite seven-foot telescope, he noticed a strange object in the constellation of Gemini that had the distinct shape of a solid disk. Its dim light did not glimmer and flicker like a star, but remained steady and true, like the reflected light of a planet. He was not quite sure what to make of it, yet he knew he needed to make a decision as to its nature and announce his find.

Herschel decided to announce his discovery as a new comet. This news caused a stampede of other astronomers to their instruments in order to verify the new celestial event. Yet, as Herschel continued to observe, it became clear to him, and eventually to other astronomers, that the object's behavior indeed appeared to be consistent with the behavior of a planet. It had a defined edge like a planet, and its nearly circular orbital motions were in harmony with those of the other established planets. Comets were known to have very elliptical orbits, not circular. After using parallax measurements, he also found that the new object was far beyond Saturn, the sixth (counting Earth) and farthest planet at edge of the known solar system. Eventually, it was officially determined that Herschel's discovery was indeed a new planet, one that existed at roughly twice the distance from the Sun as Saturn! This tore a great rift in the ancient knowledge that defined the size of the solar system based on the placement of the six planets. The discovery of this seventh planet nearly doubled the size of the solar system. This was fascinating news! Suddenly the telescope was again popular in a way not seen since Galileo discovered the moons of Jupiter in 1610.

Telescopes Mastery

Telescopes Mastery

Through this ebook, you are going to learn what you will need to know all about the telescopes that can provide a fun and rewarding hobby for you and your family!

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