[flagged]
There's a new-ish rule on HN:
> Don't post generated comments or AI-edited comments. HN is for conversation between humans.
No one cares about what ChatGPT had to say to you on TFA. What do you have to say about it?
We still don't have a more precise value for "Big G"
21–30 of 69 posts
Re: We still don't have a more precise value for "Big G"
#22[flagged]
You must feel so smart.
Re: We still don't have a more precise value for "Big G"
#23[flagged]
how is this at all related to TFA
Gravity experiments? Easier to do accurately in lower gravity environments, like away from the Earth? And we just so happen to have a nearly permanent laboratory in orbit, which was built and is maintained at tremendous taxpayer expense?
I thought this would be obvious from TFA. I should have been more explicit.
Re: We still don't have a more precise value for "Big G"
#24I appreciate the scientists’ honesty. When asked about big G and time invariance, he says he just takes it on faith that it has been the same forever. If more people would admit their leaps I think the theistic schism would be far more shallow.
The theistic schism? I had to look it up, and was not cleverer after. Nobody can ever know an ultimate why, for obvious and well established philosophical reasons. At least the scientists are trying to squeeze the knowledge gap down as small as possible instead of making up stories.
Re: We still don't have a more precise value for "Big G"
#25I appreciate the scientists’ honesty. When asked about big G and time invariance, he says he just takes it on faith that it has been the same forever. If more people would admit their leaps I think the theistic schism would be far more shallow.
The theistic schism? I had to look it up, and was not cleverer after. Nobody can ever know an ultimate why, for obvious and well established philosophical reasons. At least the scientists are trying to squeeze the knowledge gap down as small as possible instead of making up stories.
> Nobody can ever know an ultimate why, for obvious and well established philosophical reasons
Yes we can, you are just presupposing that philosophy is ultimately ineffective. For example Hegel gave a presuppositionless development of all metaphysics among other things. It’s not some kind of philosophical consensus that ultimate justification is impossible
Re: We still don't have a more precise value for "Big G"
#26> Cavendish painstakingly recorded those oscillations to measure the gravitational force of the larger spheres on the smaller ones, and from that he could infer Earth’s density.
I can't wrap my head around this sentence. How is the force between two objects, none of which is the earth, related to any property of the earth (its mass or density)? Wouldn't Cavendish's experiment have worked - even better - in zero g and given the same result? There is something more to his setup beyond two big weights pulling on each other that I'm probably missing?
Re: We still don't have a more precise value for "Big G"
#27> Cavendish painstakingly recorded those oscillations to measure the gravitational force of the larger spheres on the smaller ones, and from that he could infer Earth’s density. I can't wrap my head around this sentence. How is the force between two objects, none of which is the earth, related to any property of the earth (its mass or density)? Wouldn't Cavendish's experiment have worked - even better - in zero g and…
By ascertaining an approxiamte value of G , perhaps? After that, you know M_earth, and already knowing Earth’s geometry, one arrives at average density rho.
Re: We still don't have a more precise value for "Big G"
#28I appreciate the scientists’ honesty. When asked about big G and time invariance, he says he just takes it on faith that it has been the same forever. If more people would admit their leaps I think the theistic schism would be far more shallow.
> If more people would admit their leaps I think the theistic schism would be far more shallow. There’s an important gap here between science as practiced and science communication. Working scientists will absolutely admit their ignorance, shaky foundations, etc. This is especially important in astronomy and cosmology, as the field is relatively young and experiments are impossible, outside of those that nature has a…
Thank you for the nice read. I empathize with many of your points, we are standing on the shoulders of giants. I refute on the claim around "our greatest societal ills". I think there is a difference between confident communication and being listened to. I have many a times said confidently "I don't know", as I have made decisions on low confident bets but leant into them with all my heart. Sometimes it paid of and sometimes it did not. It has served me well in my career and in life. As a scientist at heart I still agree that too often confidence is given too much weight and the quiet voice in the room should also be heard. However, we should teach everybody to communicate confidently even if they sometimes communicate wrongly. Of course we should not confuse confidence with credibility and accept that we know little for sure and are all just trying our best with the very limited understanding we have of our universe.
Re: We still don't have a more precise value for "Big G"
#29Earlier quoted context omitted.
It might also be nice if cosmologists stopped claiming their Big Bang "Theory" wasn't more accurately termed a mere Hypothesis. IIRC, 12 out of 13 predictions failing and necessitating "model" "tweaks" is not a fantastic track record for a Theory, which are supposed to robustly survive investigation.
The model failing is a question of how accurately you want it to model the world. Many laypersons have absolutely no conception of how accurate those "failing" models were. A good example is Newtonian physics. Strictly speaking it is a failing model, after all, under certain conditions and if you look very closely ot falls apart. Yet, every bridge you ever walked on and the most precise mechanical watches ever made w…
This is what has always made it hard for me to go beyond the Newtonian physics. The only thing I know and use daily that relies on relativity is GPS and having looked into the equations on how it accounts for this it seemed to me that I could not discount that the equations account for some arbitrary consistent (or random) error, not relativity specifically. All experiments I have run never needed precision beyond Newtonian physics, but I am not at the end of my career yet so maybe relativity will become relevant some day. I will be looking forward to it if that is the case...
Re: We still don't have a more precise value for "Big G"
#30> Cavendish painstakingly recorded those oscillations to measure the gravitational force of the larger spheres on the smaller ones, and from that he could infer Earth’s density. I can't wrap my head around this sentence. How is the force between two objects, none of which is the earth, related to any property of the earth (its mass or density)? Wouldn't Cavendish's experiment have worked - even better - in zero g and…
By ascertaining an approxiamte value of G , perhaps? After that, you know M_earth, and already knowing Earth’s geometry, one arrives at average density rho.
Yup, that's exactly it:
- get the gravitational constant with these two known masses
- then can deduct the mass of the unknown Earth by its interaction with other masses (say the "g" gravitational acceleration value)
- then from the mass and the otherwise measured size of Earth the density pops out
More details in good ol' Wikipedia: https://en.wikipedia.org/wiki/Cavendish_experiment#Derivatio...