Pulsar Proves Gravitational Constant is "Rock Solid"

This thread is based on an article from Space.com (link below)

Space.com article

Researchers using the National Science Foundation's telescope in West Virginia, along with the Arecibo telescope in Puerto Rico, studied a specific pulsar for 21 years straight!

Astronomers using the National Science Foundation’s (NSF) Green Bank Telescope (GBT) in West Virginia and its Arecibo Observatory in Puerto Rico conducted a 21-year study to precisely measure the steady "tick-tick-tick" of a pulsar known as PSR J1713+0747. This painstaking research produced the best constraint ever of the gravitational constant measured outside of our Solar System.

I've always thought gravity was such a fascinating force. It literally shapes our universe, our experiences, our abilities, and imposes many limitations in the scientific and technological approach to problem-solving.

To help illustrate how this study produced the findings that it did, here is an excerpt:

This particular pulsar is approximately 3,750 light-years from Earth. It orbits a companion white dwarf star and is one of the brightest, most stable pulsars known. Previous studies show that it takes about 68 days for the pulsar to orbit its white dwarf companion, meaning they share an uncommonly wide orbit. This separation is essential for the study of gravity because the effect of gravitational radiation – the steady conversion of orbital velocity to gravitational waves as predicted by Einstein – is incredibly small and would have negligible impact on the orbit of the pulsar. A more pronounced orbital change would confound the accuracy of the pulsar timing experiment.

I found that this article says a lot. The gravitational constant, is in fact constant. Meanwhile, Einstein's theory of relativity which states that energy = mass times the speed of light squared, has many paradoxes (that's not to say that Einstein was "wrong" or that his theory of relativity has no value - not at all please don't misinterpret what I'm saying here)

hrough extremely high precision measurements of a pulsar orbiting a white dwarf star, astronomers have found that the gravitational constant, which dictates the force of gravity, is "reassuringly constant" throughout the universe.

This seems like an astronomical find (pun intended )

But I want to hear what my ATS friends have to say about this. What do we REALLY know about the universe? WIll something come out months or years down the road that question this "constant"?


My bet is that Yes, there will always be "anomalies" and freak phenomena that defy everything we thought we knew. But maybe this time it will be different...

a reply to: FamCore

Relativistic theory, both of them, have no paradoxes whatsoever, the paradoxes would exist only were the theories not adhered to in the Universe. What in the world are you referring to? Also when I was at University, as a Physics major, we kind of gathered the gist of why we referred to it as the Universal Gravitational Constant, LOL.

Perhaps I don't understand it enough, as this section of the Wiki article "Paradoxes" specifically says "Insufficient knowledge of the basics of special relativity, especially the application of the Lorentz transformation in connection with length contraction and time dilation, led and still leads to the construction of various apparent paradoxes. "

it then continues with:

Both the twin paradox and the Ehrenfest paradox and their explanation were already mentioned [in article]. Besides the twin paradox, also the reciprocity of time dilation (i.e. every inertially moving observer considers the clock of the other one as being dilated) was heavily criticized by Herbert Dingle and others. For example, Dingle wrote a series of letters to Nature at the end of the 1950s. However, also the self-consistency of the reciprocity of time dilation was already demonstrated long before in an illustrative way by Lorentz (in his lectures from 1910, published 1931[A 21]) and many others—they alluded to the fact that it is only necessary to carefully consider the relevant measurement rules and the relativity of simultaneity. Other known paradoxes are the Ladder paradox and Bell's spaceship paradox, which also can simply be solved by consideration of the relativity of simultaneity.

So my mistake

a reply to: catjuggler

en.wikipedia.org...


I don't understand physics too well apparently

Great find. Can't wait till they start measuring the gravity near the black hole in the centre of the milky way to see if it truly is constant in all corners of the universe.

a reply to: catjuggler

Universal gravitational constant was based on measurements in our solar system right? Wasn't the whole point of the study to see if it occurred in other parts of the cosmos? Find it strange that as a scientist you would laugh at it when you only had a "gist".

originally posted by: catjuggler
a reply to: FamCore

Relativistic theory, both of them, have no paradoxes whatsoever, the paradoxes would exist only were the theories not adhered to in the Universe. What in the world are you referring to? Also when I was at University, as a Physics major, we kind of gathered the gist of why we referred to it as the Universal Gravitational Constant, LOL.

Being that I didn't go to University for physics, and I didn't have sufficient knowledge of the basics of special relativity, AND there are apparent paradoxes put forth by other people with similar misunderstanding, it is reasonable to understand that some people might not understand these constants, so while you may be superior in your understanding of this, it might be better if you contribute something to the discussion about the topic other than condescension , thank you

I have a hard time figuring out what _exactly_ is a Gravitational Constant. What happens to Newton's gravitational equation if you ignore G and just use the masses and the distance between them? Was G simply invented to make the equation match experiment results?

Same goes for the Cosmological Constant, too.

I think when we have a complete understanding of gravity, faster than light travel and time travel will be ours for the taking. Just my humble opinion.

a reply to: wildespace

Newton's laws on gravity were incorrect. The orbit of mercury was his downfall.

a reply to: Nickn3

We understand its impact on bodies and that's about all but its strength has been dialled to guarantee life in our reality, which is extraordinarily amazing all in itself. Personally I feel that gravity is not a force at all but a by-product of the curling of space-time into what we perceive as matter. Perhaps all that really exists is space-time, described as brane's in super-string theory.

originally posted by: FamCore So my mistake

I don't understand physics too well apparently

Jeez, FamCore, this is ATS: When confronted with the possibility that you might be wrong, you're supposed to dig your heels in and cling to your discredited position tenaciously and call those who disagree with you "shills" and "sheeple" (or ignore them completely and just repeat the same errors in countless threads for the next 2 - 4 years).

You're not supposed to do further research, find better sources or (Heaven forbid!) try to learn. How do you expect to get anywhere with an attitude like that?!

a reply to: FamCore

I seem to recall that not too long after pulsars were discovered that there was one that was not "ticking" regularily. Speeding up I think it was. Perhaps it was found to be a instrumentation error?

originally posted by: rossacus
a reply to: wildespace

Newton's laws on gravity were incorrect. The orbit of mercury was his downfall.

They are correct enough that we still use them to calculate gravitational attraction between bodies and to launch rockets.

originally posted by: rossacus
Great find. Can't wait till they start measuring the gravity near the black hole in the centre of the milky way to see if it truly is constant in all corners of the universe.

Already done via tracking the motions of stars around it. Constants by their very nature are the same throughout the universe.

originally posted by: wildespace

originally posted by: rossacus
a reply to: wildespace

Newton's laws on gravity were incorrect. The orbit of mercury was his downfall.

They are correct enough that we still use them to calculate gravitational attraction between bodies and to launch rockets.

Well said. Star for you since no one else did.

originally posted by: wildespace
I have a hard time figuring out what _exactly_ is a Gravitational Constant. What happens to Newton's gravitational equation if you ignore G and just use the masses and the distance between them? Was G simply invented to make the equation match experiment results?

No.

Also quantum interferometry and pulsar timing networks will get a more accurate measurement of G. This is an area which is constantly being revised (no pun) as new techniques help measure a force that is so much weaker than electromagnetism or the two nuclear forces.

originally posted by: Aliensun
a reply to: FamCore

I seem to recall that not too long after pulsars were discovered that there was one that was not "ticking" regularily. Speeding up I think it was. Perhaps it was found to be a instrumentation error?

I'm glad you brought this up! I'm going to look into that a little more - I'm betting you're right that it was instrumental error of some sort, considering this "astronomical" find theyre claiming here

originally posted by: wildespace
I have a hard time figuring out what _exactly_ is a Gravitational Constant. What happens to Newton's gravitational equation if you ignore G and just use the masses and the distance between them? Was G simply invented to make the equation match experiment results?

Same goes for the Cosmological Constant, too.

Depends on what you mean with "invention". From a certain pov yes, G is invented because it's a number that defines a relation, like Pi is invented as the number that defines the relation between a circumference and its diameter.
If you mean a "random number that could be anything else" then no, because otherwise the predictions of the orbits would be far off, you have to remember this number was calculated experimentally.

Wheter it is a universal constant or not is an issue and not a simple one because all other methods are subject to a lot of prior assumptions and we can't "weight" planets, not even ours.
What this observation says is that 3k light years from here the measurements still matches the GR theory of gravitational waves. I would be so keen to immediately expand this concept to universal, but sensationalism is what you will find on popular media.