Galileo discovered planet Neptune?

[Galileo]

Galileo discovered planet Neptune?

Press Trust Of India

Melbourne, July 07, 2009

Astronomer Galileo Galilei may have discovered Neptune in 1613 - 234 years before the planet was officially found, according to a new theory.

Prof David Jamieson of the University of Melbourne has claimed in his theory that the notebooks of Galileo from some 400 years ago contain concrete evidence that he had discovered a new planet in 1613, which is now known as Neptune.

And, according to him, if correct, the discovery would probably be the first new planet, identified by humanity since deep antiquity.

Galileo was observing the moons of Jupiter in 1612 and 1613 and recorded his observations in his notebooks. Over many nights he had also recorded the position of a nearby star that does not appear in any modern star catalogue.

"It has been known for several decades this unknown star was actually planet Neptune. Computer simulations show the precision of his observations revealing that Neptune would have looked just like a faint star almost exactly where Galileo observed it.

"Galileo may indeed have formed the hypothesis that he had seen a new planet which had moved right across the field of view during his observations of Jupiter over the month of January 1613. If this is correct Galileo observed Neptune 234 years before its official discovery," Prof Jamieson said.

http://www.hindustantimes.com/StoryPage/StoryPage.aspx?sectionName=HomePage&id=28becd27-26bb-4033-8fb2-a7369792c6c9&Headline=Galileo+discovered+planet+Neptune%3f

[MG1962]

No chance..... there is no way he could have resolved Neptunes movement against the background stars in only one month of observation

[Galileo]

No chance..... there is no way he could have resolved Neptunes movement against the background stars in only one month of observation

He did. He observed and wrote down that the "fixed star" had moved.

Please, never underestimate the powers of Galileo!

[bobdroege7]

But did he ever say, "eureka, that's a new planet"

no I guess not

that is the difference between observation and perception

[Galileo]

But did he ever say, "eureka, that's a new planet"

no I guess not

that is the difference between observation and perception

No, Eureka is not an Italian word. Galileo did observe the wandering star Neptune. A paper on this was published about 30 years ago that claimed Galileo observed, but did not "discover" Neptune.

This new paper seems to claim that Galileo did more than just observe, but he also perceived.

[Skeptical Greg]

A paper on this was published about 30 years ago that claimed Galileo observed, but did not "discover" Neptune.

Operative word has been bolded ..

[elgarak]

No chance..... there is no way he could have resolved Neptunes movement against the background stars in only one month of observation
Neptune has a orbital period of ~60,200 days (~165 years), which means it moves about 0.18 degrees during one month (very rough estimate, since I assume observing from the Sun, not Earth). Galileo's telescope had a field-of-view of about 0.25 degrees. Easily observable, if one has a fixed star as reference (and one could see the not very bright Neptune).

Galileo had already found blemishes on the Sun, and that Earth was not the center of the universe, and it got him enough trouble already. Finding a new planet? Foggedit!

[Galileo]

Operative word has been bolded ..

Presumably, the claim is documented in the paper.

I know that it has already been documented that Galileo noticed the shift in position of Neptune, without claiming it to be a new planet. It has been reported that Galileo was puzzled by it's change in position.

It has also been reported that Galileo never followed up on this, with speculation that he was busy with something else, or that Neptune was just hard to find with his telescope.

Since a new paper has been published, I would presume that some new evidence has been uncovered, possibly some more writings by Galileo, that support the claim that Galileo realized more that had been assumed.

If so, then this would be a very interesting paper.

It is also possible that the paper merely analyzes and projects backward Neptune's orbit with more certainty than was done 30 years ago.

Since Neptune was discovered in the 1800s, it has not yet completed a complete orbit of the sun. I know Galileo's drawings have been used to compute a better orbit.

There was also a mark made of Neptune in 1795 as well, in France, on another star chart, before Neptune was discovered.

Please don't be anal.

[MG1962]

He did. He observed and wrote down that the "fixed star" had moved.

Please, never underestimate the powers of Galileo!

Now complete the quote - He observed the star 27th and 28th of Jan - in that time Neptune would have moved a total of 20 arc seconds across the sky - To detect this means he had to have eyesight three times better than 20/20

To put this into normal perspective - hold your pinky at arms length - that is 1 degree in the sky - the movement he saw was 1/18 of that....I dont think so

If he had commented on the 27th Jan about the disparity from his observations on 26 Dec you would have a case, he doesn't however...nor do you.

He like a number of very famous observers after him, looked straight through the planet and never figured out a thing

[MG1962]

Neptune has a orbital period of ~60,200 days (~165 years), which means it moves about 0.18 degrees during one month (very rough estimate, since I assume observing from the Sun, not Earth). Galileo's telescope had a field-of-view of about 0.25 degrees. Easily observable, if one has a fixed star as reference (and one could see the not very bright Neptune).

Galileo had already found blemishes on the Sun, and that Earth was not the center of the universe, and it got him enough trouble already. Finding a new planet? Foggedit!

See my above post - his diary entry is across two days, not a month. Which is why I argue he would not have detected the movement

[Galileo]

Now complete the quote - He observed the star 27th and 28th of Jan - in that time Neptune would have moved a total of 20 arc seconds across the sky - To detect this means he had to have eyesight three times better than 20/20

To put this into normal perspective - hold your pinky at arms length - that is 1 degree in the sky - the movement he saw was 1/18 of that....I dont think so

If he had commented on the 27th Jan about the disparity from his observations on 26 Dec you would have a case, he doesn't however...nor do you.

He like a number of very famous observers after him, looked straight through the planet and never figured out a thing

From what I have read, he observed Neptune three times, two of them one day apart, and the third time about a month apart from the other two.

The fact is, he did see Neptune, and did write down on paper that he noticed that it moved relative to another fixed star.

Galileo also stated that "Neptune" had a different appearance than the other fixed stars.

The real question is why he did not follow this up. I hope this new paper sheds some light on that.

:jaw-dropp

[MG1962]

From what I have read, he observed Neptune three times, two of them one day apart, and the third time about a month apart from the other two.

The fact is, he did see Neptune, and did write down on paper that he noticed that it moved relative to another fixed star.

Galileo also stated that "Neptune" had a different appearance than the other fixed stars.

The real question is why he did not follow this up. I hope this new paper sheds some light on that.

:jaw-dropp

According to this article - the theory is based on a possible ammendment he made to an earlier entry in his journal

http://www.thetechherald.com/article.php/200928/4009/New-theory-claims-Galileo-discovered-Neptune

Unfortunately the doctors homepage reveals no information at all :(

[Galileo]

According to this article - the theory is based on a possible ammendment he made to an earlier entry in his journal

http://www.thetechherald.com/article.php/200928/4009/New-theory-claims-Galileo-discovered-Neptune

Unfortunately the doctors homepage reveals no information at all :(

more details:

But a planet is different than a star because planets orbit the Sun and move through the sky relative to the stars. It is remarkable that on the night of Jan 28 in 1613 Galileo noted that the “star” we now know is the planet Neptune appeared to have moved relative to an actual nearby star.

There is also a mysterious unlabelled black dot in his earlier observations of Jan 6, 1613, which is in the right position to be Neptune.

“I believe this dot could reveal he went back in his notes to record where he saw Neptune earlier when it was even closer to Jupiter but had not previously attracted his attention because of its unremarkable star-like appearance.”

If the mysterious black dot on Jan 6 was actually recorded on Jan 28, Jamieson proposes this would prove that Galileo believed he may have discovered a new planet.

By using the expertise of trace element analysts from the University of Florence, which have previously analysed inks in Galileo's manuscripts, dating the unlabelled dot in his notebook may be possible. This analysis may be conducted in October this year.

“Galileo was in the habit of sending a scrambled sentence, an anagram, to his colleagues to establish his priority for the sensational discoveries he made with his new telescope," Jamieson said, according to a MU release.

These findings have been published in Australian Physics and was presented at MU.

http://www.hindu.com/thehindu/holnus/008200907071040.htm

[Galileo]

oops! I just noiced that this was NOT published in the peer-reviewed Bentham Scientific Journal. I doubt it is legit. They should get Galileo to peer review articles about Galileo.

[Humanzee]

If I recall correctly Galileo's drawings of were pretty crude. Do you have a link were you read they were used to improve on the orbit calculations Galileo?

[Galileo]

If I recall correctly Galileo's drawings of were pretty crude. Do you have a link were you read they were used to improve on the orbit calculations Galileo?

No, they are in a book I have at home, I think by Stillman Drake.

[Humanzee]

Thx

[Humanzee]

Hmm...not exactly unbiased :D but I'll check him out. Thank Galileo. Always looking for a new read.

[BenBurch]

There were quite a number of pre-discovery observations of Neptune if I recall correctly.

[BenBurch]

Here is the paper referred to in the OP; http://www.nature.com/nature/journal/v287/n5780/abs/287311a0.html

[BenBurch]

See also; http://books.google.com/books?id=GnrAVhVZ3wMC&pg=PA352&lpg=PA352&dq=pre-discovery+observations+of+neptune&source=bl&ots=4oupodV5R0&sig=fuaGBxQIL1YdGLOJJNFcF_eynoA&hl=en&ei=fBxUSpv2F5DUMpfWwPMI&sa=X&oi=book_result&ct=result&resnum=3

[~enigma~]

Is this pseudo-history or is there a point to this tripe?

[JoeyDonuts]

It's a Galileo thread. That gives it a high likelihood of consisting mostly of self-aggrandizing based mostly on conjecture.

[BenBurch]

JoeyDonuts, well, unlike most of these, it is mostly correct. Appears to be likely he saw it, and did not realize what he saw. So it is not a discovery, really, but an observation.

[sphenisc]

Neptune has a orbital period of ~60,200 days (~165 years), which means it moves about 0.18 degrees during one month (very rough estimate, since I assume observing from the Sun, not Earth). Galileo's telescope had a field-of-view of about 0.25 degrees. Easily observable, if one has a fixed star as reference (and one could see the not very bright Neptune).

Galileo had already found blemishes on the Sun, and that Earth was not the center of the universe, and it got him enough trouble already. Finding a new planet? Foggedit!

Assuming observation from the Earth, there while be periods of switching from prograde to/from retrograde motion where Neptune will appear almost stationary and others where it is moving considerably faster than the "average" rate.


Interestingly, Galileo's drawings show that he first observed Neptune on December 28, 1612, and again on January 27, 1613. On both occasions, Galileo mistook Neptune for a fixed star when it appeared very close—in conjunction—to Jupiter in the night sky, hence, he is not credited with Neptune's discovery. During the period of his first observation in December 1612, Neptune was stationary in the sky because it had just turned retrograde that very day. This apparent backward motion is created when the orbit of the Earth takes it past an outer planet. Since Neptune was only beginning its yearly retrograde cycle, the motion of the planet was far too slight to be detected with Galileo's small telescope.

[Galileo]

It's a Galileo thread. That gives it a high likelihood of consisting mostly of self-aggrandizing based mostly on conjecture.

This is an awesome thread, I beg to differ.

[Galileo]

See also; http://books.google.com/books?id=GnrAVhVZ3wMC&pg=PA352&lpg=PA352&dq=pre-discovery+observations+of+neptune&source=bl&ots=4oupodV5R0&sig=fuaGBxQIL1YdGLOJJNFcF_eynoA&hl=en&ei=fBxUSpv2F5DUMpfWwPMI&sa=X&oi=book_result&ct=result&resnum=3

Good find. It appears someone also spotted Neptune in 1822.

[TheDaver]

Galileo, it sounds like you want to be just like your idol, Galileo.

I should remind you that he’s dead.

Get to it.

Do not advocate suicide (or harm to another poster), even in jest.

[Galileo]

Galileo, it sounds like you want to be just like your idol, Galileo.

I should remind you that he’s dead.

Get to it.

The spirit of Galileo will never die. Galileo lives!

[Wangler]

To put this into normal perspective - hold your pinky at arms length - that is 1 degree in the sky

Then move your pinky closer so that it subtends an angle greater than at arms length by the based upon the magification of his telescope: if his telescope magnified ten times then move your pinky closer to your eye, so that it appears ten times larger

- the movement he saw was 1/18 of that....


Thought I would clarify this a bit.......

[BenBurch]

Galileo, it sounds like you want to be just like your idol, Galileo.

I should remind you that he’s dead.

Get to it.

Do not advocate suicide (or harm to another poster), even in jest.

I don't read it that way, Lisa. Not even close...

[Stellafane]

There were quite a number of pre-discovery observations of Neptune if I recall correctly.

True. In fact one was by John Herschel, son of Willian Herschel, discoverer of Uranus. Thus the two outer planets came an inch from being discovered by a father-and-son team. (What are to odds, right?) Herschel fils was magnanamous in his failure, however, saying that it was a far greater accomplishment to discover Neptune via mathematical calculation and deduction, while his discovery would have been more or less an accident.

[Beerina]

No chance..... there is no way he could have resolved Neptunes movement against the background stars in only one month of observation

You've studied the level of granularity and error deviation of Galileo's scientific records, and can report it was well above that needed to detect Neptune?


Links, please! This stuff fascinates me!

[I Ratant]

This is an awesome thread, I beg to differ.
.
It's the same as every other thread you post.
Clueless.
Noticing something moved in the sky is not the same as "discovering", which means making it public for others to observe and confirm.

[Damien Evans]

Galileo discovered planet Neptune?

Press Trust Of India

Melbourne, July 07, 2009



http://www.hindustantimes.com/StoryPage/StoryPage.aspx?sectionName=HomePage&id=28becd27-26bb-4033-8fb2-a7369792c6c9&Headline=Galileo+discovered+planet+Neptune%3f

I've heard about this before, and while it is almost certain that Galileo did indeed see Neptune he didn't realise what it was and marked it down as a star, although he did note it shifted slightly in position.

With the equipment he had at his disposal he wouldn't have been able to see any detail of Neptune and would have found it visually indistinguishable from a dim star.

[Soapy Sam]

Just as well he didn't announce any such discovery. He might have found things even hotter by 1633.

[Mojo]

True. In fact one was by John Herschel, son of Willian Herschel, discoverer of Uranus. Thus the two outer planets came an inch from being discovered by a father-and-son team. (What are to odds, right?) Herschel fils was magnanamous in his failure, however, saying that it was a far greater accomplishment to discover Neptune via mathematical calculation and deduction, while his discovery would have been more or less an accident.


Much like Galileo's observation. Interesting that Galileo doesn't seem to have been able to make the conceptual leap between an observation of a star that moved and the possibility that it was a new planet.

[Mangoose]

It was very lucky for him that Neptune happened to have a near conjunction with Jupiter while he was observing the Jovian moons. He wouldn't have had another opportunity like that again until May 1626. But it looks like by that time he wasn't doing daily observations of Jupiter but had moved on to microscopal work.

[Galileo]

Much like Galileo's observation. Interesting that Galileo doesn't seem to have been able to make the conceptual leap between an observation of a star that moved and the possibility that it was a new planet.

Another way to identify a planet from a star is if you can resolve a bounded orb, rather than just a light point. I have not read the paper, but it is possible Galileo noticed this as well. Also, planets do not twinkle, only stars do.

It is possible likely that initially Galileo thought he just made a measurement error. By the time he realized it might be a planet, he might not have been to find it. Galileo's telescope had a very small field of view.

[paximperium]

I have not read the paper, but it is possible Galileo noticed this as well. There is a theme here.

Also, planets do not twinkle, only stars do. Please tell the folks here why stars "twinkle" and planets don't.

It is possible likely that initially Galileo thought he just made a measurement error. By the time he realized it might be a planet, he might not have been to find it. Galileo's telescope had a very small field of view. So he didn't discover Neptune. Thanks for clearing that up.

[Galileo]

There is a theme here.
Please tell the folks here why stars "twinkle" and planets don't.
So he didn't discover Neptune. Thanks for clearing that up.

I have not read the paper because it is not online. I will wait for the book to come out.

Have YOU read the paper?

If Galileo noticed that Neptune moved, then he discovered a planet.

twinkle, twinkle

[paximperium]

I have not read the paper because it is not online. I will wait for the book to come out.

Have YOU read the paper? No, hence I don't make things up based on not reading something.

If Galileo noticed that Neptune moved, then he discovered a planet. No. Not unless he put 2 and 2 together and actually concluded it.

twinkle, twinkle
Still waiting. So why do stars twinkle and not planets?

[MG1962]

Another way to identify a planet from a star is if you can resolve a bounded orb, rather than just a light point. I have not read the paper, but it is possible Galileo noticed this as well. Also, planets do not twinkle, only stars do.

His scope was way too small to do that. Conventional wisdom suggests that you need a scope of about 70mm to realise you have a planet rather than a star. Even at this level, Neptune looks like a slightly fat colourless star.

We can pick it out of the crowd now, because we know what we are looking at. Galileo was hampered by the fact he didn't know what he was supposed to be seeing in the first place. You can see similar results with Saturn which at one stage he thought looked like a planet with ears.

To see any colour in the star (Neptune) you need at least a 4 inch or 100mm scope, and to see any sort of disk, you need 6inch or 150mm. All well beyond the technology he had available at the time.

Uranus presents an equally puzzling problem. In the pre electric light, industrial revolution, sky, it should have been visible from time to time. Yet none of the ancients all the way back to 5000BC ever reported seeing anything that could be the planet.

I wonder what effect discovering Neptune in the 1620's would have had on Maths. its discovery much later was seen as a validation of maths and the Newtonian universe. However I wonder if they could have worked backwards to compute Uranus' orbit.

But what was...was - we cant change that

[MG1962]

Still waiting. So why do stars twinkle and not planets?

Air is made up of cells that move change shape drift around. The more agitated the sky is - the worse the seeing is. As objects get closer to the horizion, because of the curvature of the Earth the amount of air between the observer and object increase, hence increasing the sparkling effect. This becomes so bad, even planets like Venus can sparkle

To the naked eye a planet presents a vast amount more surface area to the observer than a star, so they are less suspectable to the individual air cells than a star

[Galileo]

No. Not unless he put 2 and 2 together and actually concluded it.



But in 1613, more than two centuries before Neptune was officially discovered, Galileo Galilei knew he had found it

http://www.space.com/scienceastronomy/090709-galileo-neptune.html

[Mangoose]

BTW, this week Neptune is right now in a near conjunction with Jupiter after Jupiter started a retrograde movement, just as it was in 1613. So if you want to spot Neptune with binoculars, check it out this week....the view should be close to this:

http://www.space.com/php/multimedia/imagedisplay/img_display.php?pic=090708-Neptune-Jupiter-02.jpg&cap=Use+Jupiter+to+find+the+faint+planet+Neptune.+ This+is+the+view+on+July+12+at+3+a.m.+EDT.+They+sc ene+is+almost+the+same+at+that+time+of+morning+any +day+this+week+or+next.+Credit%3A+Starry+Night+Sof tware

[Humanzee]

Have you seen how small Galileos telescope was, Galileo? I've seen Neptune in an 8" scope and it was not obviously a planet. In a scope like Galileos it would have been downright, er, stellar. :D

[Reality Check]

What the University of Melbourne physicist David Jamieson is saying according to the science article (http://www.space.com/scienceastronomy/090709-galileo-neptune.html) is that Galileo
Actually observed Neptune.
"On the night of Jan. 28, 1613, Galileo wrote in his notebook that the star we now know is the planet Neptune appeared to have moved relative to an actual nearby star, Jamieson said."
May have realized that meant that he had observed a planet:
"He added: There is also a mysterious unlabeled black dot in his earlier observations of Jan. 6, 1613, which is in the right position to be Neptune."I believe this dot could reveal he went back in his notes to record where he saw Neptune earlier when it was even closer to Jupiter but had not previously attracted his attention because of its unremarkable star-like appearance," Jamieson said.".
May have recorded this.
"Galileo was in the habit of sending a scrambled sentence, an anagram, to his colleagues to establish his priority for the sensational discoveries he made with his new telescope," Jamieson notes. "He did this when he discovered the phases of Venus and the rings of Saturn. So perhaps somewhere he wrote an as-yet un-decoded anagram that reveals he knew he discovered a new planet."
The first point is reaaonable but an observation is not really a discovery - that comes when you tell people about the observation.
In fact this observation has been known for some time, see for example the paper "Galileo's observations of Neptune" (http://articles.adsabs.harvard.edu/full/1997BaltA...6...97S) published in 1997 (this includes the notebook pages of Dec 27 1612 and Jan 28, 1613).

The second point is speculation. Galileo did not write in the notebook what he thought. He wrote what he observed. Galileo may have thought nothing. Galileo may have thought that he had observed a moon. Galileo may have thought that he had made a mistake in his previous diagram. Galileo may have thought that he had observed a planet.

The third point is the main one. Galileo lived for 29 years after this observation. If he had written an anagram to his colleagues to establish his priority then why did he not follow up on it?

Why did he take the secret of a new planet to his grave?

IMHO:
Galileo thought exactly what he wrote down - the star appeared to move. He did not realize the significance of this.

[I Ratant]

...
Galileo thought exactly what he wrote down - the star appeared to move. He did not realize the significance of this.
.
The real G was working up what would be Square One for future courses in Astronomy 101, which built on what he and many others found to be going on out there.
The concept of anything new wasn't really prominent then.
That most of what would be observed was found to be new hadn't been firmed up at that time.
It took a lot more work to get to the ideas that are modern astrophysics today.

[Caradoc]

.

Noticing something moved in the sky is not the same as "discovering", which means making it public for others to observe and confirm.

Yes, but with Galileo we have some evidence that if he wasn't sure about something, he's record it but hide the knowledge (e.g. his little code for "I have pbserved saturn to be triple). So it wouldn't be that shocking to find he did something else and put it in some hidden place in his writings.

[Mangoose]

I thought the anagramed message on Saturn (sent publicly to fellow astronomers in late July 1610) was intended to establish the time of the initial discovery to prevent others from claiming the discovery as their own during the time the discovery was being confirmed, a period lasting three months. So it had to be a public message so that the time was commonly known. But the information was not altogether hidden privately; he sent a private letter describing the discovery to his Medici patrons at the same time and his private notebooks are filled with his notes and observations.

I see no evidence in his private writings that he made the connection that the stella fixus he observed in 1613 was in fact categorically a planet.