I find myself confused. I would appreciate any reference that explains HOW the rotation of the planet creates the effect of frame dragging. Is it perhaps just related to the irregularity of the planet's geometry?
Hi @DaveC426913 and @pinball1970:
I apologize for the confusion. I was referring to the 1979 series rather than the 2011 movie.
https://en.wikipedia.org/wiki/Tinker_Tailor_Soldier_Spy_(TV_series)
Also: 4 = Great = Excellent. 3 = Very Good. 2 = Good. 1 = Fair/Poor.
Regards,
Buzz
I have a list of over 300 movies organized into four groups by my preferences. The following is my group #4 with 41 titles.
Tape #
#
Start H:M
Len H:M
Year
Rating
Title (Notes)
67
1
0:12
2:37
1991
4
All Passion Spent (Brit – widow of prime minister)
53
1
0:01
1:30
1954
4...
I can conceive of a planet (Earth) in its early time having many different chemistry phenomena leading to many different pre-life systems. I can conceive that of the many different pre-life forms, only one was much more competitive than all the others, so only one survived as life chemistry as...
I would much appreciate it if someone would make clear what the following abbreviations mean: MN and N1.
The reference is from post #56 by @mfb.
39 MN for SLS (Block 2 will have 41 MN)
35 MN for Saturn V
31 MN for the Space Shuttle
45 MN for N1.
A bit of Wiki research has led me to understand the nomenclature regarding the distinction between cellular life and viruses.
Virology is the scientific study of biological viruses. It is a subfield of microbiology that focuses on their detection, structure, classification and evolution, their...
Biology is the scientific study of life.
https://en.wikipedia.org/wiki/What_Is_Life?
https://en.wikipedia.org/wiki/Life
I get that the understanding of life has changed a great deal over the centuries. So what? So has Physics and Astronomy.
For some people, making jokes about the changes over...
Hi @fresh_42:
Your question: "Now, what exactly is life?"
Wikipedia limits life to cells, so viruses are not included.
Your statement is unclear to me: "The initial picture was a comparison of sciences to human bodies."
Can you explain the "initial picture" in some detail? Is it intended to...
Most (perhaps all?) of the posts just seem to me to be attempts at humor. I will make an attempt at seriousness.
https://en.wikipedia.org/wiki/Biology
With respect to this reference, does anyone have a serious comment about its contents?
Hi @PeterDonis:
I will try to do the math to understand the implications of your thought:
"it is not the case that, for a finite universe with a positive cosmological constant, all of the finite universe will eventually be within the observable universe of a particular comoving observer."
This...
My understanding may be flawed, but I think that in principle the quote in Post #7
"It seems very doubtful that observation can ever solve the question whether or not the universe is spatially infinite," timmdeeg ,
and the quote in Post #8
"Observations could prove the universe is finite. If it...
Scientific American
June 2, 2022
Vol 32 Number 6
Page 62
Title: Skin Cancer around the World
Two Quotes:
“The main cause of skin cancer is the exposure to the sun’s ultraviolet rays…”
“UV radiation is about 40% stronger in New Zealand than it is at corresponding latitudes in the Northern...
Hi @George Jones and @Bandersnatch:
Thank you very much for your posts. I now get the mistake in thinking which I was experiencing. I blame it all on my very advanced years.
Regards,
Buzz
Hi @andrewkirk:
Thank you for your response. Your identifying "if the universe is flat" as referring to "its large scale structure" is exactly what I intended. I appologize for not being as clear as I should have been.
I am somewhat confused by your calling the two nodes in exact opposite...
The implication seems to be that from the beginning of the post expansion era, there was everywhere an average velocity of a large volume of matter which was (very near) zero everywhere with respect to a common fixed coordinate system (with a spacially uniform time expansion of distances)...
Today I learned that the number 2222 is an "Angel Number" with quite a detailed description of its personal influence.
See https://angelnumber.org/2222-angel-number/.
When I touch my watch near one of its straps, it displays the time and also the number of steps I have taken since I put the...
Hi @George Jones:
Re #33, my intent was to use the equation approach I presented (which you quoted in #33) to obtain a numerical result of about 13.8 giga-years. I finally was successful in Post #19. I was not trying to find a different way to integrate. Thank you for your interest.
Regards,
Buzz
Hi @PeterDonis:
Well, I finally completed #19, and now have shown the process that produces a correct numerical result for the integral.
Regarding #36, your equation
$$dt = \frac {1}{H_0} {\frac {da} { \sqrt {M/a+L a^2}}} $$
becomes
$$dt = \frac {{\sqrt {a}} da} {H_0 \sqrt {M+L a^3}}$$
by...
Hi @PeterDonis:
I did make an error in Post #35. Is is OK with you if I fix it with edits until I decide I have it right?
I think for any post I write I need to preface it with
"THIS IS A WORK IN PROGRESS,"
so if I make an error I can correct it before someone has responded to my error before...
Hi @PeterDonis:
I do not understand why the integrand I uses is not equivalent to the integrand you posted.
Mine is
$$dt = \frac {dx} {3H_0 \sqrt L \sqrt{x^2 + 2Qx} }$$.
Yours is based on
$$dt = \frac {dx} {3H_0 \sqrt L \sqrt{x^2 + 2Qx} }$$.
The process of integrating involves a sequence of...
Hi @PeterDonis:
I do not understand why the integrand I used is not equivalent to the integrand you posted.
Mine is
$$dt = \frac {da} {H_0 a \sqrt {M/a3+L}} = \frac {{\sqrt {a}} da} {H_0 \sqrt {M+L a^3}}$$
Yours is based on
$$dt = \frac {da} {H_0 \sqrt{M/a + La^2} }$$.
The difference is...
Hi @mbond:
Thank you for your post. I would much appreciate it you would post the reference of the integral with the x variable which leads to your "t = ..." equation. The equation I reached is
$$t = { \frac {1} {3H_0 \sqrt L}} {\ln ( {x+Q + \sqrt {x^2 + 2Qx} } ) }$$.
If this is wrong, can you...
Hi @George Jones:
Thank you for responding to my problem. I should have made clear that I have not completed the presentation I am working on in Post #19.. The equation with ##t = ## has errors due to my lack of experience using LaTeX I have not fixed yet. The equation should be
$$t = { \frac...
Hi @pbuk:
I am very familiar with the reference you posted. My first LaTeX equation in Post #19 is based on the equations in your reference, except I omit ##Ω_r## and ##Ω_k##.
Regards,
Buzz
THIS POST IS NOW COMPLETED.
Note that I have finally corrected my errors and have calculated an expected result.
$$dt = \frac {da} {H_0 a \sqrt {M/a3+L}} = \frac {{\sqrt {a}} da} {H_0 \sqrt {M+L a^3}}$$
I make the following substitutions.
##{x = a^3,}## ##{a = x^{1/3}},## ##{da = dx /...
Hi @PeterDonis:
I very much appreciate your comments and your advice. I will start a new post with a gradual intent to attempt to use LaTeX to complete the sequence that explains the integration.. When I edited Post 1, I alternated editing and then posting so I could see if the LaTeX I used...
Hi @PeterDonis:
I am editing Post #1 to try to convert equations to LaTeX, but I am so far not able to succeed on my first equation. Can you help me?
Regards,
Buzz
Hi @Bystander:
Your comment "Order of magnitude, second digit is excessive/hubris," does not communicate to me at all. I just do not get what you are trying to tell me.
Regards,
Buzz
I found https://www.physicsforums.com/threads/introducing-latex-math-typesetting.8997/ .
It says I should click on various examples of LaTeX use, to see the details of how to use LaTeX for the examples. HOWEVER, clicking on the examples have no effect at all!
Hi @PeterDonis:
It has been a very long time (years) since I last used LaTeX. My memory about it has vanished. Would you please tell me how I can find the instructions about how to use LaTeX?
Regards,
Buzz
NOTE: I am attempting to convey the equations in this post into LaTerX format in Post #19.
My result is way off. It is about 7.44 x 10^9 years. The values I use are:
1/H_0 = 14.4 X 10^9 years,
M = Ω_m = 0.3103, and
L = Ω_Λ = 1 - Ω_m = 0.6897.
The equation I start with is the following.
dt =...
My references are:
https://en.wikipedia.org/wiki/Friedmann_equations#Detailed_derivation
https://en.m.wikipedia.org/wiki/Cosmological_constant
Ω_Λ is a term in the Friedmann equation along with terms for radiation, mass, and curvature.
Λ is the coefficient of the term g_μν in the Einstein field...
Thank you very much @PeterDonis and @Orodruin. I conclude now that I do not have sufficient detailed understanding of the processes leading to the Means and Standard Deviations. Therefore, the best I can do is just use the Ω_m values. Intuitively I am guessing that there is some way to combine...
I thank all of you for the clarifying the relationships regarding the three parameters. What remains unclear to me is if I want to use a value for Ω_m to calculate the age of the universe, based on the three Omega values what is the value most likely to give me the most accurate age?
By the...
Hi @Vanadium 50:
Thank you for your comment. The "problem" is my confusion about how the independent measurements of the three variables can result in a disagreement in the addition of two variables (Ω_b and Ω_c) whose sum does not equal the third variable (Ω_m) which is by definition: the...
Ω_b = Baryon density parameter = 0.0486±0.0010.
Ω_c = Dark matter density parameter = 0.2589±0.0057.
Ω_m = Matter density parameter = 0.3089±0.0062.
But
Ω_b + Ω_c = 0.3078±0.0067.
I would much appreciate any explanation about why this unexpected relationship with the three parameters is...
Hi @epenquin:
I am wondering what you use of "TYL" means. I looked at https://www.abbreviations.com/TYL and decided it was probably "Thank You Lord". Did I get it right?
Regards,
Buzz
Hi @Martyn Arthur:
I confess I am not sure I understand your point of view in Post #1, but I think that you may have missed the role of the Hubble constant H_0. Ignoring gravity, two galaxies which are right now at a distance D from each other will be moving away from each other at a velocity...
I decided to take a different approach to this topic in another thread. It will take me some time to figure out how to organize it. I have found some improved reliable values for the necessary parameters. The following are integration results using these "new" parameter values and using both...
ADDED: I FOUND MY MISTAKE! I fixed it below.
I very much want to thank @George Jones for his post to this thread. I have been trying for a week to grasp the process leading to the conclusion regarding the age at the universe at the time of Recombination, but I keep coming up with a wrong...
The Wikipedia references is
https://en.wikipedia.org/wiki/Recombination_(cosmology).
It says:
Recombination occurred about 370,000 years after the Big Bang (at a redshift of z = 1100),
and
the cosmic background radiation is infrared [and some red] black-body radiation emitted when the universe...
For the record, I did a bit of searching and learned that Jacinda Ardern is Prime Minister of New Zealand.
I suppose it was probably not necessary with "TNZ" ending "Stevie".
Hi @Bandersnatch:
Thank you very much for your response. If I understand it correctly, the Friedmann equation with Omegas requires that there is no solution of the equation that permits recollapsing of the universe. I now see that I was mistaken about the possibility that some combination of...