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Chapter 8

NATS 1745 Chapter Notes - Chapter 8: Johann Daniel Titius, Caroline Herschel, John Couch Adams


Department
Natural Science
Course Code
NATS 1745
Professor
Robin Metcalfe
Chapter
8

Page:
of 5
Chapter 8: Planet Hunters
Textbook Notes
William Herschel; German musical teacher, composer and astronomer
Summary: Discovered Uranus in 1781
Born in 1738 in Germany
Musical accomplishments:
i) His father, Issac taught him the violin and the oboe
ii) William took up oboe in the regimental band, left for England
iii) He became a professional musician, ending up as an organist and composer in Halifax, and
later at the Octagon Chapel in Bath where he settled with his sister Caroline Hershel (Their
house at 19 New King Street, has been restored as a museum called ‘Hershel House’)
iv) After a fight with Thomas Liley music director of Music, Herchel won, drove Liley out of
town and became the Director of Music
v) Organized concerts all over Bath
Their house at 19 New King Street, has been restored as a museum called ‘Hershel House’
Classic book of Harmony was by Dr. Robert Smith
Doubled the size of the solar system in 1781
Astronomy accomplishments:
i) The love of astronomy was instilled by his father
ii) He later went on to build a reflecting telescope (he couldn’t afford to buy one)
iii) His obsession was mapping the sky and attempting to measure distances to the stars
iv) His theory was that if he could find two stars almost in line, the nearer one should appear to
move lightly as the Earth travels around the sun
v) In 1781, he found a new ‘star’ in Gemini
vi) He noted in his journal “a curious either Nebulous Star or perhaps a comet”
vii) Astronomy Royal’s Nevil Maskelyne, was already speculating it could be a planet
viii) Sure enough, it was a new planet
ix) He had discovered a new world in the solar system, a world 4 times the size of Earth and
15 times heavier
x) In 1787, Herschel later went on the discover two of the planets largest moons. It has 22.
Naming the new planet
i) Herschel wanted to name the planet in honor of King George III
ii) However he was overruled, and George later became ‘Uranus’
iii) Uranus a primeval Greek God representing the sky, son and later husband of Gaia, the
Earth
Later in life
i) Herschel was later called to Windsor by George III, to serve as the King’s private astronomer
ii) He was set up in a house with his sister in Slough
iii) People began to flock to meet the accomplished astronomer
iv) Later began building telescopes
v) His greatest was “Forty Foot”
vi) He then married Mary Pitt
His goal in life was to make a complete survey of the heavens and to discover the
architecture of the comets
Joseph Haydn, renowned composer
i) Traveled to Slough to meet Herschel and look through his telescopes
ii) He was apparently so astounded, it inspired him to write The Creation
Caroline Herschel, sister of William and accomplished astronomer in her own right
i) After her brother got married to Mary, she destroyed all of her journals
ii) 16 years she assisted and cared for her brother, hand fed him as he made his monstrous
mirrors
iii) She went on to discover eight comets as well as nebulas and galaxies
iv) In 1828, she was awarded The Royal Astronomical Society’s prestigious gold metal
v) The Society didn’t give a woman another award until 1996
Johannes Kepler, the first person to predict there could be more planets in 1596
He wrote “between Jupiter and Mars, I would put a planet”
To him, it was obvious that there was a yawning gap between Jupiter and Mars
Johann Daniel Titius, German mathematician
Summary: Created the formula Titius-Bode Law
Derived a formula to describe the planets distances from the sun
His formula was taken by Johann Bode, prolific astronomer who was the director of the
Berlin Observatory
Titius-Bode Law (unfairly known now as Bode’s law) is simple:
Distance from the earth to the sun is 10 units, then the six known planets had distances of
approximately 4,7,10,15,52
The gap between 15 and 52 was noticeably large. There should be a world at about 28 units.
Herschel made his discovery of Uranus, a name Bode proposed, which turned out to be 192
units from the sun. It was chillingly close to Bode’s prediction of 196
The obviousness that there is a planet in between Mars and Jupiter became more
embarrassing
Bode dubbed themselves, The Celestial Police and they went on a mission for the missing
world
Guiseppe Piazzi, an Italian astronomer working in Sicily
Summary: Discovered ‘Ceres’
In 1801, Piazzi came across a rapidly moving ‘star’ at exactly the right distance (28) from the sun
Piazzi named the new world ‘Ceres’ after the patron goddess of Sicily
William Herschel, was not impressed
He coined the term ‘asteroid’ as an insult for his discovery and looked down on him
The discovery was so small, it appeared to be a star, that’s what asteroid means. (it was a third
the size of the moon)
However the tradition of naming objects after ancient heroes continued with Pallas, Vesta and
Juno
John Couch Adams, a young mathematician at Cambridge
Summary: Theoretically found a new planet
He set out to calculate where the missing planet might lie
In 1843, he knew where the planet would be found
He informed James Challis, a Professor of Astronomy at Cambridge
Challis did give John an introduction to the Astronomy Royal, George Airy
George Airy was arrogant and dismissed them
Airy didn’t believe you could discover unknown bodies from the position of known ones
Adam’s had discovered the location of the planet theoretically however, In 1846 – the new
planet was discovered at the Berlin Observatory by Johann Galle
Urbain Leverrier, mathematician at the Paris Observatory
Was on the same track as John Couch Adams
He published his prediction of the unknown planet in the sky in 1846
No one would cooperate with him on the search
Discovery of Neptune:
On September 23, he wrote to the Berlin observatory with his predictions, the observatory’s
assistant, Johann Galle
i) He was disappointed that he couldn’t find anything
ii) Heinrich d’Arrest, a young student suggested that they check the stars against the charts
iii) As they called out starts and checked against the positions before long, Galle called out a
start position that led d’Arrest to exclaim ITS NOT ON THE MAP, they had found the eight
planet.
Naming Neptune:
i) A new planet needs a new name
ii) Having seen the planets bluish green disc for the first time, they opted to name it after the
classical god of the sea, Neptune