# Scale invariance of empty space? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [December 2, 2017, 7:52pm UTC](https://boards.straightdope.com/t/scale-invariance-of-empty-space/803370 "2017-12-02T19:52:46Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [December 2, 2017, 7:52pm UTC](https://boards.straightdope.com/t/scale-invariance-of-empty-space/803370/1 "2017-12-02T19:52:46Z")
Recent news reports of a new theory say that it eliminates the need for dark matter and dark energy. [Here’s the paper](https://arxiv.org/abs/1710.11425). I’ll admit to not understanding it. Is this something new? I Have a vague memory of seeing something similar before, but may be confusing it with something else. Is it likely this guy is on to something? ---
**Author:** ![SamuelA](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@SamuelA](https://boards.straightdope.com/u/SamuelA)\ **Post date:** [December 2, 2017, 9:33pm UTC](https://boards.straightdope.com/t/scale-invariance-of-empty-space/803370/2 "2017-12-02T21:33:17Z")
Here’s how I perceive this kind of thing. The _easiest to use_ theory that fully explains all observations of the universe to date and works on production data sets is the one we should be using. It doesn’t matter what the “truth” is, since that is unknowable, just that whatever theory, whether it be math equations or a mountain of data tables, is the easiest to use theory out of available theories. So this variant theory is only interesting if it is simpler. I don’t know if it is, either. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [December 4, 2017, 5:45pm UTC](https://boards.straightdope.com/t/scale-invariance-of-empty-space/803370/3 "2017-12-04T17:45:33Z")
SamuelA, that’s essentially how all accepted scientific theories are. OK, bumping this thread because some of our physics experts may not have seen it. ---
**Author:** ![tim314](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tim314/32/3468_2.png) [@tim314](https://boards.straightdope.com/u/tim314)\ **Post date:** [December 5, 2017, 5:28am UTC](https://boards.straightdope.com/t/scale-invariance-of-empty-space/803370/4 "2017-12-05T05:28:30Z")
Here’s what one physicist whose blog I enjoy had to say about it: > [@Sabine Hossenfelder](#): > > For those of you who merely want to know whether you should pay attention to this new variant of modified gravity, the answer is no. The author does not have a consistent theory. The math is wrong. More here: [Astrophysicist discovers yet another way to screw yourself over when modifying Einstein’s theory](http://backreaction.blogspot.com/2017/11/astrophysicist-discovers-yet-another.html) ---
**Author:** ![tim314](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tim314/32/3468_2.png) [@tim314](https://boards.straightdope.com/u/tim314)\ **Post date:** [December 5, 2017, 5:53am UTC](https://boards.straightdope.com/t/scale-invariance-of-empty-space/803370/5 "2017-12-05T05:53:12Z")
There’s a bunch more in the comments of that post, too. John Baez (another physicist I’d trust to assess this sort of thing) agrees with Hossenfelders that there’s really nothing to see here. At some point the author of the paper also shows up in the comments to defend it (but my money is on the ones criticising it.) ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [December 5, 2017, 3:08pm UTC](https://boards.straightdope.com/t/scale-invariance-of-empty-space/803370/6 "2017-12-05T15:08:31Z")
Thanks for the link. It seems to sum things up pretty well. ---
**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:** [December 5, 2017, 3:12pm UTC](https://boards.straightdope.com/t/scale-invariance-of-empty-space/803370/7 "2017-12-05T15:12:22Z")
And historically, when there have been two competing theories, one simple and one complicated, which produce the same results, it’s usually been the case that some other sort of observation has eventually come along which the complicated theory isn’t consistent with at all, but the simple one is. In other words, the complicated theory really was wrong, and not just inconvenient.