13.8 lightyears?

[ollypenrice]

31 minutes ago, apaulo said:

forums for discussion, not insult.

Indeed so, but, when I don't know about a subject, I don't express doubts about the integrity of the hard work done by others - in this case astrophysicists - to inform themselves and the rest of us about that subject. When I became interested in astronomy I found it hard to believe that we could know much about such remote things.  Rather than asserting these doubts in public, I started reading books about astronomy and, once I had an understanding of the evidence,  I found my doubts giving way to agreement.

Olly

[michael.h.f.wilkinson]

2 hours ago, apaulo said:

personally i wouldnt say you guys are right or wrong, but i wouldnt put my life savings on you being definately right, but i would have a bet you are not 100% right

Depends on what you mean by "right". I do not see our understanding of the compositions of stars change any time soon. The claim of mainly hydrogen and helium, with varying amounts of "metals" is very solid indeed. The diameter, age and evolution of the universe are much less known, but we can state what the current best theory is. We can certainly with 100% accuracy state what theories are just wrong (like the flat earth theory).

[KevG]

3 hours ago, apaulo said:

who has been on 1 or even near 1 to know for definate.

erm... NASA!  

https://www.nasa.gov/mission_pages/sdo/main/index.html

[Gfamily]

3 hours ago, apaulo said:

do we know what stars are made of. who has been on 1 or even near 1 to know for definate.

Maybe surprisingly, it's less than 100 years since it was confirmed spectroscopically that stars are predominantly made of Hydrogen. 

Spectroscopic analysis showed the presence of atoms of Carbon, Oxygen, Nitrogen, Sodium, Calcium etc, and (if thought about at all) it was broadly thought that the Sun's chemical composition was similar to the Earth's. 

It wasn't until 1925 that Cecilia Payne, for her PhD, studied the relative strengths of those spectral lines against the strength of the Hydrogen and Helium spectral lines at the different temperatures in the Sun's atmosphere, and showed that H and He were by far the most abundant elements. 

This was later described by the renowned astronomer Otto Struve as "the most brilliant PhD thesis ever written in astronomy". Although her supervisor was initially sceptical of her results, they were confirmed later. 

Cecilia Payne married Sergei Gaposchkin and continued to do pioneering work on variable stars, and became the first female head of a department at Harvard.   

Edited January 31, 2023 by Gfamily

[Ian McCallum]

23 minutes ago, Mr Spock said:

There's no point in asking a question if you don't want to hear the answer 

Isn't that a form of cognitive dissonance? 

[ollypenrice]

19 minutes ago, Gfamily said:

Maybe surprisingly, it's less than 100 years since it was confirmed spectroscopically that stars are predominantly made of Hydrogen. 

Spectroscopic analysis showed the presence of atoms of Carbon, Oxygen, Nitrogen, Sodium, Calcium etc, and (if thought about at all) it was broadly thought that the Sun's chemical composition was similar to the Earth's. 

It wasn't until 1925 that Cecilia Payne, for her PhD, studied the relative strengths of those spectral lines against the strength of the Hydrogen and Helium spectral lines at the different temperatures in the Sun's atmosphere, and showed that H and He were by far the most abundant elements. 

This was later described by the renowned astronomer Otto Struve as "the most brilliant PhD thesis ever written in astronomy". Although her supervisor was initially sceptical of her results, they were confirmed later. 

Cecilia Payne married Sergei Gaposchkin and continued to do pioneering work on variable stars, and became the first female head of a department at Harvard.   

Good post. I reviewed this recent book for Astronomy Now and highly recommend it here, too.

https://www.amazon.com/What-Stars-Are-Made-Payne-Gaposchkin/dp/0674237374

Olly

[Malpi12]

21 hours ago, AstroKeith said:

The radiation is weaker and even more 'red shifted'.,

,is a super sensitive and high resolution version of COBE

Thanks, that is what I needed to jump start my brain !

I see now that is where I was going wrong with Webb. 
I  have been happy over the years to accept that the hot glow ( the CHG ! ) from the early universe has, by now, stretched and shifted all the way to a dim 2.7-ishK CMB,   -- I have failed to apply the same to "conventional" ancient, early, bright objects like stars, galaxies and Quasars etc., (and anything else that formed at or about 'First Light') which XhaveX will also become stretched and shifted into the darkness of the End Theories --   

The clue, I think,  was there for me if I had had the eyes to see it: the fact that Webb is working in the IR. (also being able to see through intervening dust)  ?

edited to change have into will. Cant seem to do strikethro when editing ???

Edited January 31, 2023 by Malpi12

[AstroKeith]

With regard to the Sun, I think our knowledge is about 99.9%

spectroscopy was the first major breakthrough. Once stellar models were being developed and refined they could be tested against not only our sun, but many other stars were we know their mass, luminosity, temperature and spectra.

Back on Earth particle physics was filling in the gaps in the reactions. 

now we have helioseismology, neutrino and other particle detection, solar wind measurements, magnetometry and imagery in other bands.
 

[iantaylor2uk]

10 hours ago, mergatroid said:

I see no reason to believe that figure because I don't believe it's real science. It also makes no logical sense. It assumes we're at the center of the universe, which is a theological argument, i.e. humans putting themselves at the center of everything because some god put them there.

If the universe has a finite size (it doesn't) and there is no reason at all to think we're at the center of it, then we are closer to the edge of it. In that case, we'd see more galaxies in one direction than on the opposite. But we don't.

People who are qualified scientists do believe these things, and there is a scientific process whereby theories are put forward, tested against observations, and then accepted (or not) by scientific consensus as the best (current) theory. If you are not qualified in science, what you believe or do not believe carries zero weight with the scientific community. 

Also just to be pedantic, if you believe the universe is infinite, how do you define where the centre is?

Edited January 31, 2023 by iantaylor2uk
typo

[robin_astro]

I find Prof Ned Wright's cosmology FAQ is as good a  place as any to go when questions like  this come up

https://astro.ucla.edu/~wright/cosmology_faq.html

also his page here

https://astro.ucla.edu/~wright/errors.html

(Since the age of the internet and the apparent "democratisation of science" which appears to mean the promoting and rejecting of theories from people who do not have clue  and have not bothered to do the spade work have equal merit, the number of omissions he mentions from this list  which are too crazy to waste time on has grown exponentially)

As a UCLA professor of cosmology about the same age as me, he has been doing this stuff all his working life so hopefully should have as good a handle on this any anyone else by now 😉

https://astro.ucla.edu/~wright/intro.html

 

Robin

 

[saac]

7 hours ago, apaulo said:

do we know what stars are made of. who has been on 1 or even near 1 to know for definate.

oh dear.  

Jim

[saac]

7 hours ago, apaulo said:

personally i wouldnt say you guys are right or wrong, but i wouldnt put my life savings on you being definately right, but i would have a bet you are not 100% right

I'll take that bet.  I have always fancied a Takahashi.  

Jim

[Paul M]

I think it's best to approach  big subjects like physics/astronomy/cosmology from a standing start. No preconceptions or misconceptions.

My original point of enquiry when I discovered astronomy was "why?", "why am I?", "why anything?"

I didn't know what I didn't know and it took some time to find out what I didn't know. Then even more time to star to learn the stuff I didn't know. That process is ongoing for me but is rooted in a good grounding in science and its methods Developed along the way.

Knowledge should only be built on a scaffold of understanding. Otherwise its just "empty" information. Information without understanding can be counterproductive, dangerous even!

 

[Franklin]

[George Jones]

13 hours ago, mergatroid said:

That isn't a proveable hypothesis however.

No hypothesis in physics is provable.

Edit. For example, how can Newton's second law (for constant m), F = ma, be proved?

Edited January 31, 2023 by George Jones

[Paul M]

Along the route to understanding the universe as a layperson I had a number of epiphanies ( is that a word?), marked by 2 books that I remember to this day, some 45 years later:

Asimov's Guide to Science, by, er... Issac Asimov and Children of the Universe, by Hoimar VonDitfurth (sp?).

Yes, I really am made of "star stuff"!

It don't get anymore mind blowing than that!

[Macavity]

Often a good idea *is* to read a Book, or look up a *authoritative* reference!
That a scientist (subsets of?) may make "simple" mistakes, or "not know stuff",
does not prove the opposing idea. Devil's Advocacy is pretty much infinite? 😁

I also think that one cannot constantly go back to (scientific) first principles
or "Philosophy of Science" arguments. Some things you do have to take as
"read" - Or at least, have some trust in (quite often!) "rather clever" people. 😛

Edited January 31, 2023 by Macavity

[ollypenrice]

1 hour ago, Macavity said:

Some things you do have to take as
"read" - Or at least, have some trust in (quite often!) "rather clever" people. 😛

Yes. The alternative is believing that the supposedly clever people belong to some kind of 'they' who have been too stupid to realize that the things that are obvious to you have completely passed them by.

I, personally, want to call time on this and say, 'If, as an untutored beginner, you seriously think that you are going to debunk a century of rigorous science, then you are - I'm sorry - an idiot.'

This does not, absolutely not, mean you should read the science in an uncritical or non-skeptical way. That is precisely what you should do. Feynman said, 'Science is a culture of doubt.' So doubt away, but do so with a little respect.

Olly

Edited January 31, 2023 by ollypenrice
typo

[ollypenrice]

False click. Sorry.

Edited January 31, 2023 by ollypenrice

[Franklin]

There are plenty of popular science books on this kind of subject, I'm no expert but anything by Stephen Hawking, Timothy Ferris, Martin Rees to name some respected authors, should help in understanding these mind-boggling concepts.

[saac]

2 hours ago, Paul M said:

Along the route to understanding the universe as a layperson I had a number of epiphanies ( is that a word?),

Yes it is  

Jim 

[Paul M]

2 hours ago, Macavity said:

Often a good idea *is* to read a Book, or look up a *authoritative* reference!

In the 90's I had a Feynman period. I read just about every "accessible" book of his that I could find. 

Much of his work was an order of magnitude beyond my understanding but he taught me something I still recount whenever possible. One of his anecdotes was about how his father taught him the difference between knowing the name of something and knowing something.

I think we live in a world run by people who know the name of something!

There I said it... 🏃‍♂️

[saac]

2 hours ago, Paul M said:

In the 90's I had a Feynman period. I read just about every "accessible" book of his that I could find. 

Much of his work was an order of magnitude beyond my understanding but he taught me something I still recount whenever possible. One of his anecdotes was about how his father taught him the difference between knowing the name of something and knowing something.

I think we live in a world run by people who know the name of something!

There I said it... 🏃‍♂️

I'm not so sure Paul, I have faith that the engineers that design and build our aircraft, trains, bridges, tunnels etc know what they are doing. Likewise the medics that treat our injured and failing bodies know what they are doing. I can imagine somebody, a certain type of person,  having a crisis of confidence at 30,000ft  en route to their holiday destination in Spain wondering if the aircraft design engineer got it right . That certain type of person never having designed anything in their life or having any understanding of engineering. 

Jim 

[Paul M]

Just now, saac said:

I'm not so sure Paul, I have faith that the engineers that design and build our aircraft, trains, bridges, tunnels etc know what they are doing. Likewise the medics that treat our injured and failing bodies know what they are doing. I can imagine somebody, a certain type of person,  having a crisis of confidence at 30,000ft  en route to their holiday destination in Spain wondering if the aircraft design engineer got it right . That certain type of person never having designed anything in their life or having any understanding of engineering. 

Jim 

I think you misunderstood me Jim, I'm not saying scientists are a bunch on name knowing wasters. Far from it. The scientists aren't running the world. But those people that are running the world  know just enough buzz words to fool the unititated.... and themselves

I think, in  my own iterpretation of my favorite Feynman anecdote, that is what his father was saying. Beware bearers of "fake" knowledge. That warning serves us well in light of the interweb of "personal truths". Wide dissemination of misguided belief dressed up as fact, justified by buzz words and mass following; groupthink!

As for trusting airctaft desgniers, both Airbus and Boeing give us cause for concern. The 737 Max is a case in point or Air France's Flight 447 highlight the tribulations on man v poorly excecuted technology.

[saac]

14 minutes ago, Paul M said:

I think you misunderstood me Jim, I'm not saying scientists are a bunch on name knowing wasters. Far from it. The scientists aren't running the world. But those people that are running the world  know just enough buzz words to fool the unititated.... and themselves

I think, in  my own iterpretation of my favorite Feynman anecdote, that is what his father was saying. Beware bearers of "fake" knowledge. That warning serves us well in light of the interweb of "personal truths". Wide dissemination of misguided belief dressed up as fact, justified by buzz words and mass following; groupthink!

As for trusting airctaft desgniers, both Airbus and Boeing give us cause for concern. The 737 Max is a case in point or Air France's Flight 447 highlight the tribulations on man v poorly excecuted technology.

Ok I understand Paul and yes I would agree. I think the rot started to set in the 1990s with the rise of the Master of Business Administration post graduate degrees (MBAs). All of a sudden new management speak became the fashion and it was reflected in a certain rebranding of politics at the time as well "going forward" etc. A certain group of people convinced themselves that they were the masters of the universe. They lauded themselves, thinking how clever they were. In reality, all thy were doing was using obfuscated language and hollow models, or in their words empty "paradigms".  Politics and business today is still inflicted by it with companies paying more attention to their mission statement than their actual purpose. The madness is all pervasive, have you ever seen as simple a thing as a kids nursery without a "mission statement" these days.  The most recent evolution of this nonsense sees nurseries renamed as "nurture centres" - I kid you not.    As for the travails of Airbus and Boeing, look to their business managers/administrators (I bet a few MBA graduates there), engineers tend to be a very honest species by nature. My post then was more a affirmation that the people that actually matter, the professionals out their in their fields, not only know the theory but also deliver.  For what it's worth, I always sleep soundly at 30,000ft, my professional background prior to education was aircraft engineering,  I have faith, I also know which noises to ignore and which are worth worrying about  

Jim