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Easy steps to groom TabCosmo output for PF post format

by marcus
Tags: format, groom, output, steps, tabcosmo
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marcus
#1
Feb19-13, 04:36 PM
Astronomy
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P: 23,228
Different forums have slightly different formatting so if you implement an idea or discover something using Jorrie's online calculator and want to share the output table with the rest of us, these are some simple things to do to make the table clear and legible in PF setting.

For example say you keep all the settings the same as the present defaults except you change S_lower from 0.01 to 1, and you check the "copy&paste" box.

That will give a table with the top row S=1090 (the origin of the CMB radiation)
and the bottom row S=1 (the present day)
going down in 10 steps, because 10 is the default number of steps---if you want more you have to change it.

If you copy and paste the resulting table without any grooming, in "code" tags, this is what you get:
S	a	T	T_Hub	D_now	D_then	D_hor	D_par
1090.000	0.000917	0.000378	0.000637	45.731	0.042	0.056	0.001
541.606	0.001846	0.001200	0.001945	45.126	0.083	0.113	0.003
269.117	0.003716	0.003662	0.005761	44.225	0.164	0.223	0.009
133.721	0.007478	0.010876	0.016772	42.912	0.321	0.439	0.028
66.444	0.015050	0.031751	0.048364	41.023	0.617	0.855	0.085
33.015	0.030289	0.091754	0.138771	38.325	1.161	1.640	0.253
16.405	0.060958	0.263633	0.397095	34.484	2.102	3.066	0.743
8.151	0.122680	0.754694	1.132801	29.030	3.561	5.501	2.164
4.050	0.246896	2.146402	3.182937	21.343	5.269	9.172	6.254
2.013	0.496887	5.887073	8.078066	11.017	5.474	13.329	17.716
1.000	1.000000	13.753303	13.999929	0.000	0.000	15.793	46.686
Time now (at S=1) or present age in billion years:	
13.753301
Now if you erase the final zero of 1090.000 you get:
S	a	T	T_Hub	D_now	D_then	D_hor	D_par
1090.00	0.000917	0.000378	0.000637	45.731	0.042	0.056	0.001
541.606	0.001846	0.001200	0.001945	45.126	0.083	0.113	0.003
269.117	0.003716	0.003662	0.005761	44.225	0.164	0.223	0.009
133.721	0.007478	0.010876	0.016772	42.912	0.321	0.439	0.028
66.444	0.015050	0.031751	0.048364	41.023	0.617	0.855	0.085
33.015	0.030289	0.091754	0.138771	38.325	1.161	1.640	0.253
16.405	0.060958	0.263633	0.397095	34.484	2.102	3.066	0.743
8.151	0.122680	0.754694	1.132801	29.030	3.561	5.501	2.164
4.050	0.246896	2.146402	3.182937	21.343	5.269	9.172	6.254
2.013	0.496887	5.887073	8.078066	11.017	5.474	13.329	17.716
1.000	1.000000	13.753303	13.999929	0.000	0.000	15.793	46.686
Time now (at S=1) or present age in billion years:	
13.753301
Now I suggest putting cursor right ahead of each number in the third column, pressing delete and then three spaces. This shrinks the space between second and third columns from one large to 3 small spaces:
S	a	T	T_Hub	D_now	D_then	D_hor	D_par
1090.00	0.000917   0.000378	0.000637	45.731	0.042	0.056	0.001
541.606	0.001846   0.001200	0.001945	45.126	0.083	0.113	0.003
269.117	0.003716   0.003662	0.005761	44.225	0.164	0.223	0.009
133.721	0.007478   0.010876	0.016772	42.912	0.321	0.439	0.028
66.444	0.015050   0.031751	0.048364	41.023	0.617	0.855	0.085
33.015	0.030289   0.091754	0.138771	38.325	1.161	1.640	0.253
16.405	0.060958   0.263633	0.397095	34.484	2.102	3.066	0.743
8.151	0.122680   0.754694	1.132801	29.030	3.561	5.501	2.164
4.050	0.246896   2.146402	3.182937	21.343	5.269	9.172	6.254
2.013	0.496887   5.887073	8.078066	11.017	5.474	13.329	17.716
1.000	1.000000   13.753303	13.999929	0.000	0.000	15.793	46.686
Time now (at S=1) or present age in billion years:	
13.753301
At this point you can probably see how to do whatever else you think is needed for the table to look good and make sense. I would shrink the space between columns 4 and 5 down to say four small spaces, just for looks. That means put the cursor right before the number, press delete (to get rid of the big space) and press the spacebar four times. And then get the alignment of the column headings positioned right. First dealing with the space between fourth and fifth columns:
S	a	T	T_Hub	D_now	D_then	D_hor	D_par
1090.00	0.000917   0.000378	0.000637    45.731	0.042	0.056	0.001
541.606	0.001846   0.001200	0.001945    45.126	0.083	0.113	0.003
269.117	0.003716   0.003662	0.005761    44.225	0.164	0.223	0.009
133.721	0.007478   0.010876	0.016772    42.912	0.321	0.439	0.028
66.444	0.015050   0.031751	0.048364    41.023	0.617	0.855	0.085
33.015	0.030289   0.091754	0.138771    38.325	1.161	1.640	0.253
16.405	0.060958   0.263633	0.397095    34.484	2.102	3.066	0.743
8.151	0.122680   0.754694	1.132801    29.030	3.561	5.501	2.164
4.050	0.246896   2.146402	3.182937    21.343	5.269	9.172	6.254
2.013	0.496887   5.887073	8.078066    11.017	5.474	13.329	17.716
1.000	1.000000   13.753303	13.999929    0.000	0.000	15.793	46.686
Time now (at S=1) or present age in billion years:	
13.753301
And then with the headings. I put 3 small spaces before S, 3 before a, 6 before T, 9 before T_Hub, 10 before D_now, and this is what results:
   S	   a	      T	         T_Hub	    D_now	D_then	D_hor	D_par
1090.00	0.000917   0.000378	0.000637    45.731	0.042	0.056	0.001
541.606	0.001846   0.001200	0.001945    45.126	0.083	0.113	0.003
269.117	0.003716   0.003662	0.005761    44.225	0.164	0.223	0.009
133.721	0.007478   0.010876	0.016772    42.912	0.321	0.439	0.028
66.444	0.015050   0.031751	0.048364    41.023	0.617	0.855	0.085
33.015	0.030289   0.091754	0.138771    38.325	1.161	1.640	0.253
16.405	0.060958   0.263633	0.397095    34.484	2.102	3.066	0.743
8.151	0.122680   0.754694	1.132801    29.030	3.561	5.501	2.164
4.050	0.246896   2.146402	3.182937    21.343	5.269	9.172	6.254
2.013	0.496887   5.887073	8.078066    11.017	5.474	13.329	17.716
1.000	1.000000   13.753303	13.999929    0.000	0.000	15.793	46.686
Time now (at S=1) or present age in billion years:	
13.753301
You may be able to make this look better, or you may see how to get things lined up with smarter moves. I've never learned to use the large spacers. I tend to erase them and just press the ordinary space-bar to insert small (normal size) spaces. However many are needed.

You might want to insert UNITS in the headings. Like "T" is the expansion age and is measured in billions of hears (Gy). So the row with the headings could look like:
  S  a(=1/S)  T(Gy)  T_Hub(Gy)  D_now(Gly)  D_then(Gly)   D_hor(Gly) D_par(Gly)
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marcus
#2
Feb19-13, 06:04 PM
Astronomy
Sci Advisor
PF Gold
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P: 23,228
When you see a table like this what kinds of things do you want to interpret from it? In visualizing the past development of the universe a pretty good case can be made that one of the most important columns in the table to understand is T_Hub, the Hubble Time. I'll explain:

   S	   a	      T	         T_Hub	    D_now	D_then	D_hor	D_par
1090.00	0.000917   0.000378	0.000637    45.731	0.042	0.056	0.001
541.606	0.001846   0.001200	0.001945    45.126	0.083	0.113	0.003
269.117	0.003716   0.003662	0.005761    44.225	0.164	0.223	0.009
133.721	0.007478   0.010876	0.016772    42.912	0.321	0.439	0.028
66.444	0.015050   0.031751	0.048364    41.023	0.617	0.855	0.085
33.015	0.030289   0.091754	0.138771    38.325	1.161	1.640	0.253
16.405	0.060958   0.263633	0.397095    34.484	2.102	3.066	0.743
8.151	0.122680   0.754694	1.132801    29.030	3.561	5.501	2.164
4.050	0.246896   2.146402	3.182937    21.343	5.269	9.172	6.254
2.013	0.496887   5.887073	8.078066    11.017	5.474	13.329	17.716
1.000	1.000000   13.753303	13.999929    0.000	0.000	15.793	46.686
Time now (at S=1) or present age in billion years:	
13.753301
You can see that back around S=8 (i.e. distances and wavelengths have expanded 8-fold since then) the Hubbletime was around 1 billion years.
And you can always read the Hubbletime as a DISTANCE too, in this case around 1 billion light-years.

That tells you the speed distances were expanding back then. A billion light-years is the distance that was expanding at the speed of light.
So, at that time, a distance of 5 billion lightyears was growing at a speed of 5c---five times the speed of light.

The Hubbletime, or equivalently the Hubbledistance, gives you an easy way to do arithmetic in your head when picturing past conditions. For example, look along that row which has S approximately equal to 8, and Hubbletime around 1 billion.

You see that the Horizon distance is around 5.5 billion lightyears. If at that time a galaxy was CLOSER than that, then its light from that era will eventually reach us. So for example think of one that was 5 Gly from here (from this matter that eventually became us and the solar system). Then that galaxy was receding at around 5c, and the light it emitted right then will eventually reach us.

But it hasn't yet. Notice on the same row the number 3.5 in the D_then column. Light from a galaxy that was, at that era, 3.5 billion lightyears from us is now reaching us. How fast was that galaxy receding when it emitted the light we are now getting? About 3.5c.

That is what I mean about making mental arithmetic easy. The Hubbletime(or distance) is a key piece of information about the past.

It is also the main number you use if you want to make the calculator into a "time machine".
If you want to go back to the S=8 era in history, when Hubbletime was about 1 Gy, and get a look at how things were, then when you bring up the calculator you simply replace the default Hubbletime of 14.0, at the top of the page, by whatever Hubbletime you want, say in this case 1.0, or thereabouts.

The Hubbletime you can control (called Y_now, at the top of the page) is that defining the PRESENT PERSPECTIVE, i.e. what you want to be your "now". The default is set to 14.0 because that is what it actually is today. But it is the main lever on the time machine---the main thing you get to control.

The table has a lot of information packed into not very many numbers, I want to mention examples like this to illustrate how one can interpret or unpack what's there.
==========
EDIT: I would suggest not changing Y_inf = 16.5. It is a constant characteristic of our universe, equivalent to the cosmological constant (overimaginatively called "dark energy"). If you change the default 16.5 then effectively you are no longer in our universe and for all I know it could hang your computer or something. I like our universe and have not even considered monkeying with that particular default setting.
Jorrie
#3
Feb19-13, 10:43 PM
Jorrie's Avatar
P: 757
I am looking at a proper "Copy table" button that will format the data correctly into tags for pasting. A sort of "self-grooming" feature for PF, which essentially owns the calculator - it was a collaborative effort.

Eventually, I would like to transfer it to somewhere on the forum (off my private website), but have no idea if that is possible. Will Admin perhaps give advice on that? I realize that maintenance issues may become a problem, but on the other hand, private websites have the tendency to disappear under some circumstances...


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