What Happens if We Remove a Planet from the Solar System?

[Rader]

Kepler +Titus-Bode law

Just to clarify,I have read that William Hershal used Keplers law to search the sky, in the orbit that it should be found. Kepler lived 1571-1630, Bode 1747-1826, Willliam Hershal 1738-1822. Bode's law had no theoretical justification when it was first introduced; it did, however, agree with the soon-to-be-discovered planet Uranus' orbit (19.2 au actual; 19.7 au predicted). Similarly, it predicted a missing planet between Mars and Jupiter. Then did Hershal and Bode work together to find Uranus? I have not found this. It has been said that Herschal searched the skies using what was know of Keplers law.

 

[selfAdjoint]

I do not know If Herschell used Bode's law, if he did it could only have been as an aid. The way Herschell found Uransus was by analyzing the unexplained perturbations in the motions of Saturn and Jupiter. These planets were found to be sometimes a little ahead and sometimes a litle behind their schedules as computed from Newton's theory.

Herschell assumed these perturbations were due to an undiscovered planet's gravity acting on them. He worked out the forces and was able to locate the planet by crossing two lines of force (actually I'll bet there were more than two!). Once he had a single position, he could use Kepler's third law to figure the orbital period of the new planet, and then he could revise his calculations with old data interpreted in light of that period, and so compute the orbit of the planet he proposed to name Georgium, and which some wanted to call Herschellium, but which was finally named for the Greek sky god Uranus (latinization of Ouranos).

I don't believe Herschell and Bode, who lived in different countries, ever worked together.

 

[Nereid]

AFAIK, Herschel found Uranus by accident, not as the result of a dedicated search (Neptune, however, was discovered not far from where it was predicted, using Newton's laws and the observed deviations of Uranus' orbit from what it should have been if there were only 6 planets).

At the time the first asteroids were discovered (Ceres, in 1801), it was noted that its orbit was about where the Titus-Bode law said there should be a planet, and at first it was thought that Ceres might be that planet.

 

[Rader]

the lucky find

Originally posted by Nereid
AFAIK, Herschel found Uranus by accident, not as the result of a dedicated search (Neptune, however, was discovered not far from where it was predicted, using Newton's laws and the observed deviations of Uranus' orbit from what it should have been if there were only 6 planets).

At the time the first asteroids were discovered (Ceres, in 1801), it was noted that its orbit was about where the Titus-Bode law said there should be a planet, and at first it was thought that Ceres might be that planet.

Methodical plate inspecion was Herschels method, like they use to search comets.

It is often said that Herschel found Uranus accidentally but this was disputed by Herschel himself. As he correctly pointed out, he was using the finest telescope in the world, in a systematic survey of the sky when he came upon the seventh planet. He was certain in his own mind that he would have eventually discovered it given his methodical search. As it was the planet had been sighted and noted in star charts no less than 20 times in the prior 90 years. Shortly after discovering Uranus Herschel found Uranus' two largest Moons Oberon and Titania.
http://www.frostydrew.org/observatory/columns/2002/may.htm

 

[Nereid]

Rader wrote: Methodical plate inspecion was Herschels method, like they use to search comets.

According to the information in the site below, the first photographic plate of a star wasn't taken until 1850, long after Herschel death.

http://www.astro.virginia.edu/~afs5z/photography.html

As to how specific the goals of Herschel's observing were, the material you cite certainly has an authentic ring to it. However, I wonder to what extent he was searching for a seventh planet - and had good reasons for why he searched where he did - as opposed to a general interest in the sky, and was systematically searching the sky for anything interesting?

 

[Rader]

good point

Originally posted by Nereid
According to the information in the site below, the first photographic plate of a star wasn't taken until 1850, long after Herschel death.

http://www.astro.virginia.edu/~afs5z/photography.html

As to how specific the goals of Herschel's observing were, the material you cite certainly has an authentic ring to it. However, I wonder to what extent he was searching for a seventh planet - and had good reasons for why he searched where he did - as opposed to a general interest in the sky, and was systematically searching the sky for anything interesting?

Nereid you have a very good point. Is there a site that is open to the public to retrive documents on discovery that are written by there authors. Over time things get distorted. It would be great to know the scientfic process of exactly how, not just dates and general info. In his days he did not have computers and automatic CCD plate trasing of certain sections of the sky. It was time consuming plate inspection. Some comets are found by looking for a needle in a haystack but its usually not the case. I would like to know that answer regarding Uranus.

 

[selfAdjoint]

Originally posted by Rader
Nereid you have a very good point. Is there a site that is open to the public to retrive documents on discovery that are written by there authors. Over time things get distorted. It would be great to know the scientfic process of exactly how, not just dates and general info. In his days he did not have computers and automatic CCD plate trasing of certain sections of the sky. It was time consuming plate inspection. Some comets are found by looking for a needle in a haystack but its usually not the case. I would like to know that answer regarding Uranus.

Herschell did not have photography of course, it did not exist in the 18th century. He (or more often his sister) made drawings. I do not know if he had a micrometer on his telescope which would have enabled scale drawings.

 

[Nereid]

Originally posted by Rader
Nereid you have a very good point. Is there a site that is open to the public to retrive documents on discovery that are written by there authors. Over time things get distorted. It would be great to know the scientfic process of exactly how, not just dates and general info. In his days he did not have computers and automatic CCD plate trasing of certain sections of the sky. It was time consuming plate inspection. Some comets are found by looking for a needle in a haystack but its usually not the case. I would like to know that answer regarding Uranus.

Here's an online biography (there a catch):
http://static.elibrary.com/t/thehut...nuary011998/herschelfrederickwilliam17381822/

There's a Herschel Museum in Bath, England.
http://www.bath-preservation-trust.org.uk/museums/herschel/index.html

And a William Herschel Society, which has a number of publications, as well as a regular newsletter:
http://www.williamherschel.org.uk/publications.htm

There are also several biographies of William Herschel in dead-tree material; your friendly bookstore or Amazon may be able to help you purchase one.

 

[Loren Booda]

Some guy in Australia has found more supernovae than any other individual in history by using a backyard telescope, his eyes and his memory.

 

[Nereid]

Originally posted by Loren Booda
Some guy in Australia has found more supernovae than any other individual in history by using a backyard telescope, his eyes and his memory.

Rev Evans. However, there's a guy in the US who has found oodles of SNs (more than Rev Ev by now?), but he uses CCDs.

A single run of one of the 'high-z' SN search teams is likely to turn up more SNs than an amateur will find in a year.

Who keeps track? CBAT does:
http://cfa-www.harvard.edu/iau/lists/RecentSupernovae.html