On Friday, February 5, 2021 at 6:28:39 AM UTC-7 Alan Grayson wrote:
> On Friday, February 5, 2021 at 6:13:32 AM UTC-7 [email protected] wrote: > >> On Thu, Feb 4, 2021 at 9:13 PM Alan Grayson <[email protected]> wrote: >> >> >>In relativity mass and energy are the same thing, remember E=MC^2, so >>>> the kinetic energy needed to do work comes from the mass/energy released >>>> by >>>> vacuum potential energy falling outward. In a similar way a hydroelectric >>>> dam produces electrical energy that can do work from the potential energy >>>> released by water falling inward. >>>> >>> >>> *> But rest energy is positive whereas potential energy is negative. How >>> do you expect negative potential energy to transform into positive rest >>> energy? AG* >>> >> >> You've asked that exact same question before and I've answered it before, >> it does it the same way a hydroelectric dam transfers negative potential >> energy into positive energy that can do work; in the case of normal matter >> like water that's done by falling inward, in the case of vacuum energy >> that's done by falling outward. >> >> *>>> Is this the GR expression for PE, which you earlier stated is >>>>> different from Newtonian physics? * >>>>> >>>> >>>> >> No. The formula for gravitational potential energy is the same in >>>> both Newtons and Einstein's theory. >>>> >>> >>> *> I could swear you posted the opposite recently. When I have the >>> motivation, I'll try to find it. AG * >>> >> >> The formula for gravitational potential energy is the same in both >> theories, although Newton didn't know about E=MC^2 or vacuum energy so the >> calculations sometimes differed, sometimes only slightly sometimes by a >> lot. For example Newton would've said that 2 hot iron cannonballs placed >> one foot apart and 2 cold cannonballs at the same distance would have >> exactly the same gravitational potential energy, but Einstein would say >> they would not because the hot iron cannonballs had more energy and thus >> have more mass than the cold iron cannonballs. >> >> >> If vacuum energy really does exist then It's an intrinsic property of >>>> space itself and so it doesn't move, it always stays the same, so I >>>> guess you could call that rest mass if you want but I don't know why >>>> you'd want to. Light moves as fast as things can go and has zero rest >>>> mass, >>>> but even a photon of light has a gravitational field, in fact if you >>>> concentrated light enough into a small enough volume it would turn into a >>>> Black Hole. Such a ball of light is called a "Kugelblitz". >>>> >>> >>> *> Didn't you assume your sphere has some initial mass in the form of >>> "sand"? * >>> >> >> I gave two examples, the first was a sphere made of normal matter like >> sand, as the radius R of the sphere got larger the mass stayed the same, >> so according to the formula for gravitational potential energy PE= >> (-G*M^2)/R becomes less negative and more positive, and that means it's >> uphill and so would need work to accomplish. In my second example I >> considered an expanding sphere of vacuum energy, in that case M does not >> stay the same but increases to the cube of R, So by using the same formula >> that means it would be downhill and can produce work. >> > *The formula for PE is valid for fixed rest mass M, and gives the PE for some value of R, the work done against the gravitational field to reach distance R from the gravitating mass. In the case of an expanding sphere of vacuum energy, by what process does rest mass increase? Also, I don't think your application of PE is correct IF the rest mass isn't fixed, but as you claim, is actually increasing. AG* > *> Or is it now light?* >>> >> > As I said Newton didn't know about E=MC^2 so he would've said light >> wouldn't produce a gravitational field no matter how intense it became, >> Einstein >> would say something different. The gravitational field produced by an >> expanding ball of light would behave differently than either a ball of sand >> particles or a ball of vacuum energy because as R got larger the number of >> photons in this sphere would remain the same but each individual photon >> would get stretched, it would get red shifted to a longer wavelength and >> longer wavelength photons have less energy, so as R increases the mass M >> would not stay the same as a sphere of sand of would or get larger as a >> ball of vacuum would but the mass would actually get smaller. >> >> >>> > *Doesn't really matter, except you have to account for positive rest >>> and kinetic energies equating to negative potential energy, * >>> >> >> The engineers who design hydroelectric dams seem to have no difficulty >> accounting for that, and neither do I. >> > > *In your model, you offer no clue about the motion of the particles > involved, and therefore no calculation of kinetic energy; hence, no > argument, plausible or otherwise, that the net total energy is "precisely > zero". AG* > >> >> >> -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/60fbbd8a-ac4b-45a6-900e-5cb628f9b899n%40googlegroups.com.
