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History of expansion.


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Since diving head long down the Astro rabbit hole I have been trying to get my hands on every book and resource I can find. After four years I could be forgiven for thinking that the modern idea for the expansion of the universe was all in the hands of Edwin Hubble. 
His legacy according to common print (paper and internet) would have you nodding in agreement as the CMB was discovered. Case closed, name the big silver telescope in space after this enigmatic man.

I have just been reading a fabulous older book by Patrick Moore in which he talks about the 24 inch refractor at Flagstaff. 
PM notes that between 1912 and 1920 the telescope was used by the famous astronomer Vesto Slipher! WHO? I hear my self saying.

Vesto Slipher used the refactor to observe the outer galaxies, and gave first proof that they are racing away from us! Hang on a minute, why I have I never encountered this man or his name in relation to expansion?

I have read numerous times that until Hubble turned his attention to M31 astronomy had no idea that they were external galaxies at all? Something just doesn’t seem right here. I am assuming that a simplified version of history has been made available so ordinary people could comprehend the enormity of the findings.

Marvin

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@Marvin Jenkins It is common in historical records, particularly around inventions to find things "incorrectly" credited. Often, the person who made the most significant contribution is credited as the discoverer or inventor and the person who was first is over-looked in the history books. A well-known example is the light bulb, the invention of which is frequently and erroneously credited to Thomas Edison who was a fantastic self-promotionalist. If you are at all familiar with the history of electric light you will know that Joseph Swann got there before him, but there were others who pre-dated Swann. However, none came up with a commercially viable product. One of them was none other than Humphrey Davey, the chemist.

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I do remember hearing a commentary for a cricket match a few years ago where that very subject came up. 
It may have been a West Indian Cricketer that commented that the invention of the Tungsten filliment made the lightbulb workable and how the history books do not mention this man at all.

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My own reading of astronomy history makes it very clear that Hubble continued the observations of Vesto Melvin Slipher, who is regularly cited in astronomy history. To be honest, almost everything I've read on the matter makes this clear, so I think you've been unlucky in your choice of texts if you have only just met him. You're certainly right to note his contribution. However, the story is convoluted because Hubble was happy to ride the tide of fame which followed Einstein's interpretation of the linear distance-velocity relation Hubble discovered. But we must moderate our view of Hubble as the the 'discoverer' of the expansion since he never entirely believed it - or never even believed it at all.

It is for professional historians of science to get to the bottom of all this but my own suspicion is that much of the story hangs on Hubble's troubled personality. He craved adulation and spent his scientific life searching for discoveries that would immortalize him. When Slipher ran out of aperture, I think Hubble spied an opportunity and went for it with the Hooker. And I suspect that his reluctance to accept the expansion of the universe as the explanation for his distance-velocity discovery was that this explanation wasn't his but Einstein's. He hoped to find some 'new physics' to explain the phenomenon (as did Fritz Zwicky with his 'tired light' hypothesis.) Maybe the last knockings of this quest for a new physics found their final expression in Halton Arp, who continued to challenge the redshift-distance theory to the end.

Anyway, I hope that all readers of astronomy history agree that the expanding universe has two fathers, Slipher and Einstein. Hubble and Humason (don't under-estimate Humason) might be considered the midwives. :D

Olly

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2 hours ago, ollypenrice said:

My own reading of astronomy history makes it very clear that Hubble continued the observations of Vesto Melvin Slipher, who is regularly cited in astronomy history. To be honest, almost everything I've read on the matter makes this clear, so I think you've been unlucky in your choice of texts if you have only just met him. You're certainly right to note his contribution. However, the story is convoluted because Hubble was happy to ride the tide of fame which followed Einstein's interpretation of the linear distance-velocity relation Hubble discovered. But we must moderate our view of Hubble as the the 'discoverer' of the expansion since he never entirely believed it - or never even believed it at all.

It is for professional historians of science to get to the bottom of all this but my own suspicion is that much of the story hangs on Hubble's troubled personality. He craved adulation and spent his scientific life searching for discoveries that would immortalize him. When Slipher ran out of aperture, I think Hubble spied an opportunity and went for it with the Hooker. And I suspect that his reluctance to accept the expansion of the universe as the explanation for his distance-velocity discovery was that this explanation wasn't his but Einstein's. He hoped to find some 'new physics' to explain the phenomenon (as did Fritz Zwicky with his 'tired light' hypothesis.) Maybe the last knockings of this quest for a new physics found their final expression in Halton Arp, who continued to challenge the redshift-distance theory to the end.

Anyway, I hope that all readers of astronomy history agree that the expanding universe has two fathers, Slipher and Einstein. Hubble and Humason (don't under-estimate Humason) might be considered the midwives. :D

Olly

I agree with nearly everything you said but how dare you say anything about Chip Arp. 
The Patrick Moore book noted at the beginning of this thread clearly says Arp is one of the finest observers in history and his observations cannot be questioned.

In all truth we are dealing with scientific discoveries by human beings. The latter part of that statement means anything is possible. Does that mean Penzias an Wilson are wrong?

Oh no what have I said😱

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Until about 1920 one of the great debates in Astronomy was whether the 'spiral nebulae' were objects contained within the Milky Way galaxy, with the alternative view being that they were external objects - galaxies in their own right. 

So, although Slipher may have identified that the nebulae had significant radial velocities; it wasn't definitively clear to astronomers that they were at particularly high distances.

It was the  work of Henrietta Leavitt to determine the Period Luminosity law for Cepheid variables (and the bigger telescope) that allowed Hubble to determine their distances, and thus demonstrate that they were external galaxies rather than part of our own. 

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On a serious note I must have been unlucky or absent minded with regard to  Slipher. It just came as such a surprise to read that one paragraph in book from the 1980s.

Another surprise recently is reading a very up to date book about astronomy using the big scopes over the last 100 years. Not a mention of Vera C Rubin but I found myself saying “Who is Vera C Rubin” after reading lots of books about the history of astronomy.

Still haven’t found a book dedicated to her and her achievements.

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4 minutes ago, Gfamily said:

Until about 1920 one of the great debates in Astronomy was whether the 'spiral nebulae' were objects contained within the Milky Way galaxy, with the alternative view being that they were external objects - galaxies in their own right. 

So, although Slipher may have identified that the nebulae had significant radial velocities; it wasn't definitively clear to astronomers that they were at particularly high distances.

It was the  work of Henrietta Leavitt to determine the Period Luminosity law for Cepheid variables (and the bigger telescope) that allowed Hubble to determine their distances, and thus demonstrate that they were external galaxies rather than part of our own. 

I understand what you are saying with regard to your explanation.

However, Patrick Moore clearly states that Slipher was making observations of external galaxies and gave first proof that they were racing away from us.

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29 minutes ago, Marvin Jenkins said:

I understand what you are saying with regard to your explanation.

However, Patrick Moore clearly states that Slipher was making observations of external galaxies and gave first proof that they were racing away from us.

Yes, we now know that's what he was doing; but the current interpretation wasn't unambiguous at that time. 

Also, the presence of objects showing high red shifts isn't definitive proof of an expanding universe - it wasn't until Hubble could use Leavitt's discovery to determine the distance to the receding external galaxies, and thus come up with the Hubble-Lemaître Law.

Edit to Add - the fact that there exist rapidly receding objects is not (in itself) proof of an expanding universe. To show an expanding structure you have to be able to correlate the distance and the speed of recession.  

Edited by Gfamily
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2 minutes ago, Gfamily said:

Yes, that's what we now know that's what he was doing; but the current interpretation wasn't unambiguous at that time. 

Also, the presence of objects showing high red shifts isn't definitive proof of an expanding universe - it wasn't until Hubble could use Leavitt's discovery to determine the distance to the receding external galaxies, and thus come up with the Hubble-Lemaître Law 

I am totally confused by your entire statement. That first paragraph is a giant problem. It just doesn’t make any sense:

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18 minutes ago, Marvin Jenkins said:

I am totally confused by your entire statement. That first paragraph is a giant problem. It just doesn’t make any sense:

Yes, I had a spare 'that's what' in it.

In my first paragraph, I was trying to say that although Moore wrote "Slipher was making observations of external galaxies", it was not definite at the time that they were 'external galaxies'. We now know that's what they are - but that wasn't proven until later.

 

Edited by Gfamily
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Slipher didn't know that his spiral nebulae were galaxies, didn't know their distances and, therefore, didn't know that their redshift-distance relationship was linear or that this relation held good in all directions as viewed from the Earth. It's vital to have all that information before you can conclude that the universe is probably expanding. However, Slipher opened up the observing program which led to the missing information. As well as Leavitt, Hubble and Humason, we must also credit Harlow Shapley who found a way of calibrating Cepheids and turning them into useful tools. (Don't expect Hubble to give Shapely any credit for this! Think Robert Hooke and Isaac Newton. :grin:)

@Marvin Jenkins

I agree with nearly everything you said but how dare you say anything about Chip Arp. 
The Patrick Moore book noted at the beginning of this thread clearly says Arp is one of the finest observers in history and his observations cannot be questioned.

I wouldn't dream of saying anything against Halton Arp since, as a culture of doubt, science must have its doubters to challenge all forms of lazy orthodoxy when they appear. As for the idea that Arp's observations cannot be doubted, we must define 'observations' as distinct from 'conclusions.' As I understand it (and I'm not well read in this), Arp was interested in galaxies which showed visual signs of interaction while having radically different redshifts. The visual interactions Arp observed have been reduced to line of sight effects by most of the professional community and most certainly are questioned.

In all truth we are dealing with scientific discoveries by human beings. The latter part of that statement means anything is possible. Does that mean Penzias an Wilson are wrong?

Oh no what have I said

:grin: About what might Penzias and Wilson be wrong? That a radio signal with an effective temperature of just below 3 deg. Kelvin can found found in all directions? That's very unlikely! They found it without knowing what it was and were enlightened by Robert Johnson whom they'd unwittingly scooped. And, remarkably, I've read that none of them was aware of the work of Alpher and Herman who'd predicted the presence and temperature of the CMB from theory many years earlier.

If you want to hear real heresy, I'll give you this: Patrick Moore is not an entirely reliable historian of Astronomy. 

Olly

Edited by ollypenrice
Clarification
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  • 2 weeks later...

Very interesting. I note your final paragraph. It is interesting to me that I owned and read the book ‘BANG’ SPM Lintott and May, before the older book mentioned in my original post.

In the older book SPM clearly states Vesto Slipher as the father of expansion. 
Halton Chip ARP is quoted as saying HE is the finest observer and his observations cannot be doubted!

No mention of Slipher and Arp in ‘BANG’

M

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On 11/11/2022 at 21:41, Marvin Jenkins said:

Very interesting. I note your final paragraph. It is interesting to me that I owned and read the book ‘BANG’ SPM Lintott and May, before the older book mentioned in my original post.

In the older book SPM clearly states Vesto Slipher as the father of expansion. 
Halton Chip ARP is quoted as saying HE is the finest observer and his observations cannot be doubted!

No mention of Slipher and Arp in ‘BANG’

M

 

I don't believe expansion has a father. Like most great scientific theories it has several. Of those who contributed to it, the greatest (for me) has to be Einstein because, without him, the observers would have been looking at galaxies racing away from us - which isn't expansion. Expansion is unthinkable without a conception of relativity.

I suspect that Einstein's role in expansion is similar, in some ways, to Galileo's role in heliocentricity.  If we strip away all the oft-repeated nonsense about Galileo's spat with the church and remind ourselves that Aristarchus came before Copernicus, we might ask what Galileo really contributed to heliocentricity, given that he got De Revolutionibus suspended (not banned) by the church? Well, what he contributed was a demonstration that a rotating earth was physically possible, and that is an enormous contribution. The heliocentric model had been around for nearly 2000 years but had been consistently dismissed because it was perceived as being physically absurd. Tycho said the earth was, 'a hulking body, unfit for motion.' Galileo demonstrated that it wasn't.  Similarly Einstein demonstrated (indeed had already demonstrated) that the expansion or contraction of space was physically possible.

Olly

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