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mbenjaminsmith | 9 years ago

Maybe a physicist can tell me why I'm wrong here:

We often visualize the effect of mass on spacetime by using a trampoline and a bowling ball. The outer edges are flat and the closer you get to the bowling ball the more spacetime is warped downward.

On the outer edges, the effect is almost nonexistent and the trampoline's surface is nearly flat. What this suggests is that spacetime without mass is flat and that mass warps spacetime in a downward direction. So no mass = flat, mass = curved downward. So the effect is in the range of [0, black hole].

Obviously this is an very loose analogy but bear with me.

What if spacetime acts more like a waterbed? Not only does mass warp spacetime "downward" but something (in our analogy the displaced water) pushes the rest of spacetime upward.

To use a signal processing analogy, a filter will (nearly?) always affect the passband to some degree, with very high Q filters creating a knee where amplitude is increased significantly before the filter rolls off. That seems counterintuitive (at least to me) but it's nonetheless true.

Using another analogy, curved spacetime creates regions of "downhill-ness". What if the space between masses get a little bit of uphill curve as well? That could explain e.g., the Pioneer anomaly and possibly at much larger scales the effect in the article.

discuss

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paulddraper|9 years ago

General relativity, which describes the effect of mass on space-time, is a very elegant theory with beautiful maths. The trampoline and ball have incidental similarity, but they're for illustration only.

There's nothing that makes the waterbed theory necessarily wrong, but you'd have to posit some new maths different and more complicated than we have with GR.

mbenjaminsmith|9 years ago

Yeah, I understand that the trampoline analogy is inadequate but I believe that we don't consider empty regions of space to have any type of "opposite" curvature or to exhibit negative gravity. I believe curvature is thought to be [0, black hole], not [-black hole, black hole].

Happy to be corrected on that, IANAP.

The disparity between what GR predicts and what we observe has led to the cosmological constant / dark energy / dark matter. Of course, those aren't really things in themselves, they're just a measure of that disparity, a fudge factor.

I'm suggesting that the disparity could be explained by spacetime "responding" to regions of curvature by mass with an opposite curvature.

Unfortunately I'm not qualified to do anything with that idea. I just wanted to throw it out there. It's something that's been bothering me for a long time.

pif|9 years ago

Question: why don't you try and learn the foundations of the current theories (it's incredible how many man-centuries of high quality intellectual work you can find condensed into a book) before launching into inventing new theories out of nothing? Newton thanked the giants whose shoulders he was standing on. You are pretending you are a giant on your own. Do you sincerely believe it?

rdtsc|9 years ago

Right but he was also hit on head by an apple according to the myth. So there place for analogies like that. Also I thought your comment seemed a bit too disparaging. GP had an idea they wanted to share. There is probably a nicer way of saying it won't work than "why don't you go to the library and learn the maths before speaking up..."

mbenjaminsmith|9 years ago

> Do you sincerely believe it?

Do I believe in myself? Yes. I'm a genius (by I.Q. score) and work hard every day. That's why I own a software company and have a beautiful family, money, a passport full of stamps, etc.

Do I think I just solved one of the biggest mysteries physics? No. I think you'd have to be a moron to have read it that way as I went out of my way to say I wasn't qualified, that it was just an idea, etc. If I were a physicist and working on the idea in earnest I wouldn't have presented it here.

I don't want to make this too much of a personal attack because it's less about you and more about HN (and the internet) in general:

People like you really (actually, as in for real) make me sad. I'm 100% confident that you're not bold enough to call me an idiot in person but you're happy to do it via a textarea on a web page. That's cowardice. That's a lack of character.

Why are you like this? Because you're a loser. You don't have the courage to carve out a real life for yourself so you attack anyone you can -- especially people who seem to have the qualities you lack. That's what losers do.

Let's turn this around:

You're obviously lacking something. I'm 40 and successful and violently independent but I have had some help along the way -- people who were willing to give me advice, insight into the life of a successful person. If I can help you by way of advice or mentoring to turn your life in a positive direction, reach out to me m@lattejed.com. I'm 100% serious.

Having said that, this will be my last contribution to Hacker News. This used to be a great place for intellectual discussion. Not so anymore. Leaving has nothing to do with someone not liking my waterbed analogy -- I've been thinking about leaving for a long time. I waste too much time here and get nothing in return.

zeroer|9 years ago

The analogy to trampolines and bowling balls is leading you astray. There's no "pushing down", or even a downward direction to push in in general relativity.

jaddood|9 years ago

Actually, considering the effects of dark matter, it seems (at least to me) to be a great candidate for what you're talking about.

tylerjwilk00|9 years ago

Not a physicist, but I've been quietly hoping something like this was the case for years and would usurp Dark Matter as the reason for rotational anomaly at the outer galactic edges.

It makes sense that space-time is both attractive or repulsive based on the presence or absence matter. Throw in an overlapping inverse square law at the galactic boundary and perhaps this solves the anomaly by way of a steep gravity wall where attractive and repulsive forces meet.

Again, not a physicists either, but I agree, it seems to make sense spatially.