# mass or matter **URL:** \ **Category:** Factual Questions\ **Created:** [October 11, 2018, 2:09am UTC](https://boards.straightdope.com/t/mass-or-matter/822787 "2018-10-11T02:09:54Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![JB99](https://avatars.discourse-cdn.com/v4/letter/j/439d5e/32.png) [@JB99](https://boards.straightdope.com/u/JB99)\ **Post date:** [October 11, 2018, 10:24pm UTC](https://boards.straightdope.com/t/mass-or-matter/822787/21 "2018-10-11T22:24:37Z")
> [@MANTRAPHILTER](#): > > I’ve always considered Einstein wrong about his E=mc2 equation Wow. ---
**Author:** ![Atamasama](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/atamasama/32/12961_2.png) [@Atamasama](https://boards.straightdope.com/u/Atamasama)\ **Post date:** [October 11, 2018, 11:15pm UTC](https://boards.straightdope.com/t/mass-or-matter/822787/22 "2018-10-11T23:15:35Z")
> [@MANTRAPHILTER](#): > > He may have been smarter than I ever gave him credit for. He’s supposed to have been pretty smart, like some kind of Einstein. ---
**Author:** ![rat\_avatar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rat_avatar/32/255_2.png) [@rat\_avatar](https://boards.straightdope.com/u/rat_avatar)\ **Post date:** [October 12, 2018, 10:04am UTC](https://boards.straightdope.com/t/mass-or-matter/822787/23 "2018-10-12T10:04:13Z")
To be fair to the OP, Relativity has a high barrier to entry for a hobbyist and **most** non-relativity students and science professionals will fervently argue Einstein wrong. Example: Assumptions: Weight in intro physics books is often presented with the formula _W = mg_ or with a definition like “The weight of a body is equal to the magnitude of the gravitational force on the body.” In these same books, gravitational mass is is defined by the force of gravitation: _F = G m\_1_ m\_2/r^2\* Claim: The gravitational force exerted on an object (weight) is directly proportional to its mass. Conclusion: Thus weight and mass are equivalent. It is rare to find anyone in stem fields who will not fervently argue against this. The only difference that we can find between inertial and gravitational mass that we can find is the method. \*Einstein’s statement of the equality of inertial and gravitational mass. \* > [@](#): > > A little reflection will show that the law of the equality of the inertial and gravitational mass is equivalent to the assertion that the acceleration imparted to a body by a gravitational field is independent of the nature of the body. For Newton’s equation of motion in a gravitational field, written out in full, it is: > > (Inertial mass) \* (Acceleration) = (Intensity of the gravitational field) \* (Gravitational mass). > > It is only when there is numerical equality between the inertial and gravitational mass that the acceleration is independent of the nature of the body. Sure just like mass you could choose CGPM, Operational definitions or the ISO definitions of weight and argue the syntax of definitions. But based on the domain, there is no difference between gravitational and inertial mass as far as we can detect. One way to think of this is that at least MANTRAPHILTER is aware and willing to acknowledge doubt in Einstein, but as the _equivalence principle_ is a _postulate_ for the theory of General Relativity; arguing that weight and mass are measuring fundamentally different properties is the same effect. As I have had this discussion on the board before, let me directly quote from Einstein’s paper. \*Relativity: The Special and General Theory - Albert Einstein - 1916 \* > [@](#): > > A satisfactory interpretation can be obtained only if we recognize the following fact: \*The same quality \*of a body manifests itself according to circumstances as “_inertia_” or as “_weight_”. In closing, there is no problem with approaching the theories of Einstein with suspicion and is generally the rule that people think he is wrong they just may not know that they are saying so. ---
**Author:** ![Kiber](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kiber/32/317_2.png) [@Kiber](https://boards.straightdope.com/u/Kiber)\ **Post date:** [October 12, 2018, 1:33pm UTC](https://boards.straightdope.com/t/mass-or-matter/822787/24 "2018-10-12T13:33:56Z")
> [@Miller](#): > > [Some compelling evidence that he was right.](https://upload.wikimedia.org/wikipedia/commons/4/45/MtRedoubtedit1.jpg) Before I clicked the link I was sure that this would be a photo of an atomic weapon explosion. But then I opened it to instead find a photo of a volcanic eruption (Mt. Redoubt in 1990). So now I confess I’m a bit confused - how does a volcanic eruption support the famous equation? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 12, 2018, 2:16pm UTC](https://boards.straightdope.com/t/mass-or-matter/822787/25 "2018-10-12T14:16:37Z")
I’m guessing that **Miller** did an image search for “mushroom cloud”, and just picked out a nice impressive-looking one without paying too much attention to what was producing it. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [October 12, 2018, 3:02pm UTC](https://boards.straightdope.com/t/mass-or-matter/822787/26 "2018-10-12T15:02:08Z")
> [@rat\_avatar](#): > > One way to think of this is that at least MANTRAPHILTER is aware and willing to acknowledge doubt in Einstein… You might want to check on his posting history with regards to Einstein, starting with [All Four Forces of Physics United](https://boards.straightdope.com/sdmb/showthread.php?t=823779). ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [October 12, 2018, 4:30pm UTC](https://boards.straightdope.com/t/mass-or-matter/822787/27 "2018-10-12T16:30:26Z")
> [@rat\_avatar](#): > > To be fair to the OP, Relativity has a high barrier to entry for a hobbyist and **most** non-relativity students and science professionals will fervently argue Einstein wrong. It’s a not-completely-uncommon occurrence in libraries to get a patron who has convinced themselves that they can prove Einstein wrong about relativity, and just needs some help from staff in finding supporting documentation. I’ve been doing this for going on 30 years and it’s happened to me 3 times or so. ---
**Author:** ![rat\_avatar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rat_avatar/32/255_2.png) [@rat\_avatar](https://boards.straightdope.com/u/rat_avatar)\ **Post date:** [October 12, 2018, 5:21pm UTC](https://boards.straightdope.com/t/mass-or-matter/822787/28 "2018-10-12T17:21:16Z")
> [@Exapno\_Mapcase](#): > > You might want to check on his posting history with regards to Einstein, starting with [All Four Forces of Physics United](https://boards.straightdope.com/sdmb/showthread.php?t=823779). In GQ I prefer to limit my Bayesian priors to the question level due to SDMB’s google rank. [Previous page](https://boards.straightdope.com/t/mass-or-matter/822787.md?page=1)