Distance Calculations

[fosborn_]

But how many shells, or double layers, dielectric boundary layers between here and
even the nearest 'star'? Too many unknownsstill for me to trust even the shorter
distance calculations. Maybe Sir A is a planet just a few light days away? Siriusly

My highlights.
You didn't dispute JJohnson's summery earlier in this thread, which focused on the The Hipparcos cataqlog, so I guess you just want to be chatty.
http://thunderbolts.info/forum/phpBB3/v ... =15#p48478

The Hipparcos catalog used a satellite to make geometric parallax measurements of thousands of stars, and distances to certain stars are known with better precision than previously. In Appendix 2 of the Hipparcos Catalog is the following graph depicting the measured/calculated distances versus the percent error. By the time the distance is out to about 500 parsecs (pc), the very least error in distance is 25%, and then only for that tiny fraction of the group hugging the rising bottom edge of the grouping.

Also this response;

by GaryN »
Hi allynh,
Sorry, I didn't word that very well. I understand parallax, didn't mean
the principle was bogus, just its application to stellar distance, without,
like you say, a huge baseline.

http://thunderbolts.info/forum/phpBB3/v ... t=0#p47957
Which I refer back to JJohnson's post of the The Hipparcos catalog, for The huge baseline you desired.

In your EM thread, your concerned about rung seven on the cosmological ladder not rung 1.

The cosmic ladder looks very shaky, and it is at rung 7 where I
believe the big problems start,

http://thunderbolts.info/forum/phpBB3/v ... 150#p52670

Also, you overlooked a question of why X ray and UV stars don't out shine the visible stars in our sky
http://thunderbolts.info/forum/phpBB3/v ... 780#p53592

But you did answer it in another thread, and I did want to cover it:

http://thunderbolts.info/forum/phpBB3/v ... &start=120

GaryN » Geez you ask some tricky questions Frank. Good for you! There is much more I need to
learn about the new instruments in use, and lenses and gratings and polorisation, etc.
I'm sure there is an answer, just need to find it somehow!

My response was; its not tricky, just a simple falsification test.

[moses]

What if light travelled in a spiral ? Any curvature of the direction light travels would cause big errors in the distance calculations. I have not thought about this but it might be worth consideration.
Mo

[david barclay]

Gary,

Keep in mind that the ly is based on the speed of light remaining constant for millions and billions of years in a dynamic universe. If you really want to get to the bottom of your doubts and questions give the basics some serious consideration, such as the method employed to determine light speed and the basic assumptions derived from the resulting observation.

Then consider the calculations involved and the values presented and I think you will find that the basic assumptions concerning light speed are less than helpful and present a false view of universe in terms of both space and time.

It may seem like a fundamental issue but our modern science is based on basic fundamentals, not all of which are necessarily correct or even close to the mark. If we are mistaken about light speed the whole concept of light years falls apart.

In order for light speed to remain constant over time requires time to remain constant which suggests the possibility of time being of an absolute value. If time does not remain constant the perceived speed of light must be variable which boils down to time being variable.

I think this in itself could provide some interesting discussion as our perceptions of time and space are of some importance in understanding the nature of universe.

[GaryN]

Hi David,
I agree we are not perhaps correct with much of our science. I tend to stay away from
discussion on 'time' though, as I don't (at present!) believe it is a dimension, or some kind
of fluid we can swim back or forward in. There is only the 'now' in my reality. I do agree
though that if time were a variable, then so would the speed of light, and that would really
mess up distance calculations!
For now, I'll stay with light being affected, even over shorter distances, by mechanisms we
have not yet isolated, producing lensing/diffraction that really affects our beliefs on the
size of the Universe. It's only a matter of time (or many 'nows'? ) 'till the truth comes out.

[RayTomes]

The thread started from comparing a planet to a light bulb. I read once that Galileo was able to compare the brightness of Sirius (which he assumed to be the closest star as it is brightest) to the Sun. There is a method using wax looked at from the side to compare brightness. There are a few problems to overcome. But anyway, he got a reasonably good measure of the distance which was a little low because Sirius is brighter than the Sun.

The whole point of the exercise is that in Copernican theory we are moving around the Sun, and so should see stellar parallax which we don't. Galileo was able to show that the parallax was too small to see. It wasn't until the 1800s that parallax was detected for the first time.

[fosborn_]

The thread started from comparing a planet to a light bulb. I read once that Galileo was able to compare the brightness of Sirius (which he assumed to be the closest star as it is brightest) to the Sun. There is a method using wax looked at from the side to compare brightness. There are a few problems to overcome. But anyway, he got a reasonably good measure of the distance which was a little low because Sirius is brighter than the Sun.

The whole point of the exercise is that in Copernican theory we are moving around the Sun, and so should see stellar parallax which we don't. Galileo was able to show that the parallax was too small to see. It wasn't until the 1800s that parallax was detected for the first time.

Thanks for bringing this forward in the thread.

Parallax The Race to Measure the Cosmos by Alan Hirshfeld
Page 186

"To find the distance of the fixed stars", William Herschel told the members of the
Royal Scociety on December 6 1781, "has been a problem which many eminent astronomers have attempted to solve; but about which, after all, we remain in a great measure still in the dark"',

His explanation for this failure echoed that of the ancient Greek astronomer Aristarchus, whio initiated the quest for stellar parallax some 2000 yeras earlier;
"The whole diameter for the annual orbit of the earth is a mere point when compared to the imense distance of the stars".

I think the point is that sense ancient times the difficulty to measure parallax has always indicated great distances to the stars.
So as astronomers struggled to measure it, it was against centuries of catalogs noting exact positions of many stars. Thereby allowing efforts to study proper motions of stars.
One thing this book impressed on me was, its not just parallax to get parallax of a star. They had to know the proper motion of the star, the errors in their equipment and the star light aberration and Joseph Fraunhofer came along to help make mathematical adjustments for atmospheric conditions and show how to correct the catalogs. then in the 1800s precision machining processes began to produce new tools for astronomers. These guys were no dummies.
He demonstrated in this book, how real science works, many failures to produce a few wonderful successes.
This book was a fun and informative read.

[fosborn_]

I would like to share some more about what I have learned in this subject;
To explore a little more what advances gave astronomers the tools they needed to measure the first parallaxes.

Its funny how it was some simple things we all take for granted.
One was precision adjustments combined with a heavy stable base with balanced weights, way better than ropes and pulleys and several assistants to maneuver it all about.

Then distortion free optical systems. Then the Heliometer, a telescope with an objective lens cleanly cut in half, then with precision adjustments to align them, to measure the apparent distance between two stars. The first parallax was measured with this kind of instrument.
http://en.wikipedia.org/wiki/Heliometer

Also greater apertures, and the most excellent tool of photographic plates ( years later). This enabled more consistent measurements to be made. Often measurements varied by the skill of the observer making eyeball and note observations. But photographic plates were less prone to operational quirks.
One thing that was impressed on me is, making parallax measurement isn't a 2 shot deal. It takes many recorded observations, to provide a confident result.

Near the end of the book he gives some uses in astronomy for parallax and how important it is in other distance calculations;
Not word for word quotes.

Page 278
Parallax The Race to Measure the Cosmos by Alan Hirshfeld

a partial list of how contemporary astromomers use their newfound abundance of parallax data;

1) more accuracy to calibrate the light output of "standard stars" ( upon which rest entire framework of cosomic distance indicators).
a) other means to infer distances that lie beyond the range of parallax detection are calibrated from parallax based on stellar distances.
b) The greater the number of accurate parallax distances, the more confidence
in the leveraged methods of distance measurement.

2) To determine the light output of stars to evaluate the numerical models of stellar energy production.
a) Then use to models to infer the distances and ages and stellar composition of
remote star clusters.
3) Derive the masses of binary-star systems,( the most reliable indicator of stellar mass)

skipping some of the list;
8) Infer overall patterns of movement of stars and susequently the mass distribution within our region of the galaxy.
10) Guage more precisely how dust particles in outer space impede the transmition of starlight.

[GaryN]

1) more accuracy to calibrate the light output of "standard stars" ( upon which rest entire framework of cosomic distance indicators).

Well that 'puts the Kibosh' on the whole distance thing to me. They are assuming that
the light is from 'standard' stars, fusion powered nuclear power plants, and there is no
proof of that. If they are electric devices, then the whole works is pure nonsense.
Though I'm not totally happy with the 'standard' Electric Sun model either, it is much
closer to reality than the magic self-compressing hydrogen model.

[fosborn_]

1) more accuracy to calibrate the light output of "standard stars" ( upon which rest entire framework of cosomic distance indicators).

Well that 'puts the Kibosh' on the whole distance thing to me. They are assuming that
the light is from 'standard' stars, fusion powered nuclear power plants, and there is no
proof of that. If they are electric devices, then the whole works is pure nonsense.
Though I'm not totally happy with the 'standard' Electric Sun model either, it is much
closer to reality than the magic self-compressing hydrogen model.

Well that 'puts the Kibosh' on the whole distance thing to me.

So up to the point the distance ladder requires nuclear fusion or EU model, your okay with the distance calculations then?

[GaryN]

So up to the point the distance ladder requires nuclear fusion or EU model, your okay with the distance calculations then?

I'm OK with laser reflections from the Moon, radar to the nearer planets and asteroids,
radio signal timing to the Voyagers, and then some uncertainty creeps in. I'll go with
parallax to the nearer stars(?) within a 33% error margin, and after that, all bets are off.
You swallowing the full meal deal?

[fosborn_]

So up to the point the distance ladder requires nuclear fusion or EU model, your okay with the distance calculations then?

I'm OK with laser reflections from the Moon, radar to the nearer planets and asteroids,
radio signal timing to the Voyagers, and then some uncertainty creeps in. I'll go with
parallax to the nearer stars(?) within a 33% error margin, and after that, all bets are off.
You swallowing the full meal deal?

http://thunderbolts.info/forum/phpBB3/v ... =15#p48478

by jjohnson » Wed Mar 02, 2011 6:03 pm
The Hipparcos catalog used a satellite to make geometric parallax measurements of thousands of stars, and distances to certain stars are known with better precision than previously. In Appendix 2 of the Hipparcos Catalog is the following graph depicting the measured/calculated distances versus the percent error. By the time the distance is out to about 500 parsecs (pc), the very least error in distance is 25%, and then only for that tiny fraction of the group hugging the rising bottom edge of the grouping.

So your good out to 500 pc then?
Is that the full meal deal? Or just a kids meal?

[GaryN]

So your good out to 500 pc then?

500?? I'll go for a couple, maybe less.

By the time the distance is out to about 500 parsecs (pc), the very least error in distance is 25%, and then only for that tiny fraction of the group hugging the rising bottom edge of the grouping.

[fosborn_]

So your good out to 500 pc then?

500?? I'll go for a couple, maybe less.

By the time the distance is out to about 500 parsecs (pc), the very least error in distance is 25%, and then only for that tiny fraction of the group hugging the rising bottom edge of the grouping.

Oops. I'll post some more JJohnson;

The bulk of the stars is grouped around a "best-fit" error line running up along the elongated central dark lobe, crossing the 25% error line at roughly 250-300 pc. (1 parsec = 3.26 light years (ly) for those new to stellar distances.)

These are not insignificant errors, and Hipparcos only claims "acceptable" accuracy out to about 1000 pc, because beyond that the error values run into the thousands of percent. What this tells us that we only have a pretty good idea of how far the stars are from Earth within a radius of about, say, 1500 light years.

My highlight

[Aardwolf]

Of course, the fact that they threw out all the negative and zero parallax measurement data I'm sure is irrelevant. The data that supported what they expected to find is the important stuff anyway...

[fosborn_]

Of course, the fact that they threw out all the negative and zero parallax measurement data I'm sure is irrelevant. The data that supported what they expected to find is the important stuff anyway...

my highlights.

You all, make these blanket statements. Here is some big picture perspective;

Some 20,000 distances were determined to better than 10%, and 50,000 to better than 20%.

Hipparcos Catalogue:
Number of entries 118,218

http://en.wikipedia.org/wiki/Hipparcos

So what portion of this is discarded valuable data? If its in the remaining 48000, it won't discourage me much.