The phrase “Gravitational amplification” surely has a cool ring to it, but what do we mean with it? We’ll provide some background information and explanation first. Following that, we’ll list some potentially gravity beating ideas that are related to gravitational amplification. Wouldn’t it be cool if such an idea would inspire a future breakthrough?
But let’s not get ahead of ourselves, first things first. According to Oxford’s dictionary, part of the definition of “amplification” is simply: “the act of increasing the strength of something”[1]
That’s easy enough, but what is being amplified?
- Is gravity amplifying something?
- Or are we suggesting that something can amplify the gravitational force?
- Or is gravity amplifying itself?
Let’s tackle this confusion!
Gravity in an amplifying role
Amplification can for example refer to the well-known effect of gravitational lensing. This basically means that the force of gravity can magnify objects in space by bending and focusing light. It works similarly to a magnifying glass.
The magnifying glass analogy is a bit of an oversimplification, there is a lot more to it. See the references for some websites doing a good job explaining how gravitational lensing works.[2][3]
While “gravitational lensing”, is the term scientists commonly use for this phenomenon, some authors have referred to it as “amplification”[4]. And some even used the phrase “gravitational amplification”[5]. This use of the term matches the title of this article, however, in this article we set out to discuss something else. Magnification via gravitational lensing is super intriguing stuff but what follows has a different focus, no pun intended:)
Gravity being amplified
Now it gets (even more) interesting, as we’ll talk about the amplification of gravitational effects. Boosting gravity, heck, is that even possible? Some authors seem to think it is, and have suggested mechanisms related to the amplification of gravitational waves.[6][7] Such mechanisms though, are not likely something that will affect our daily experience of the world.
Einstein’s General Relativity theory[8][9] predicted gravitational waves[10] and the LIGO experiment[11] confirmed these in recent years. This was a monumental discovery from a scientific point of view as it opened up a whole new era of observations of our universe. Scientists anticipate many new discoveries based on gravitational wave observations.
However, gravitational waves have nothing to do with gravity as we usually experience it in our daily lives. It requires an incredibly energetic event, such as the merging of 2 black holes, to create measurable gravitational waves. And, it takes super-duper sensitive experiments to even measure the resulting gravitational waves on Earth at all. Therefore, it’s not surprising that you are not likely to ever experience one affecting your body. And please read this funny reference[12] if you don’t want to take our word for it!
Gravitational self-amplification
What is self-amplification?
Allowing ourselves to get somewhat creative with terminology, we understand self-amplification as a self-interaction that results in an amplification of the effect or force under consideration.
Self-interaction
And what is a (gravitational) self-interaction? That’s actually a rather complicated topic[13] but in this case we “simply” mean an interaction of gravity with itself. When considering General Relativity, gravity does indeed interact with itself: gravity generates (a relatively small amount of) additional gravity.[14][15]
Wouldn’t it be cool if there would be a mechanism that would allow gravity to interact with itself, amplifying itself in the process, and resulting in all kinds of unexpected things to happen? This may sound like science fiction, and seem perhaps just as outlandish as something like gravitational cancellation. However, there have been authors suggesting various gravitational self-amplification mechanisms producing measurable large-scale effects.
Some examples
- Cooperstock & Tieu have suggested there are “non-linear effects” in General Relativity that are relevant for models (galaxy rotation curves) which describe how fast stars and other material in a galaxy rotate around a galaxy’s center. These non-linear effects can be interpreted as gravitational self-interaction or self-amplification. This work has met with a lot of criticism though, which Cooperstock & Tieu then in turn have tried to address.[16]
Side note: Not convinced that it’s difficult to apply General Relativity to something like a galaxy model? Please check out Ethan Siegel’s explanation, and you’ll realize how difficult the calculations can become![17] - Deur is an example of an author who makes rather bold claims about self-interaction effects in General Relativity and the implications of these effects. Among his suggestions are potential explanations for the Tully–Fisher relation, and dark matter and dark energy[18][19] His articles have very few citations by other authors though, in fact most of the citations are by Deur himself. While this is not enough reason to completely dismiss his ideas, it’s usually not a good sign! We should admit that we haven’t dived into his equations and methods used. Anyone feeling up to the challenge though? Feel free to have a go at it and share your thoughts in the comments below🙃
- Lima & Vanzella have suggested a quantum mechanism induced by gravity, resulting in a runaway effect that produces effects on large scales (instead of only at the quantum level).[20][21]
- Numerous researchers have published articles about a “gravitational self-force” acting in the extreme environment in close proximity to a black hole, an object with an immense gravitational pull. Some researchers describe measurable effects and there are some review articles on the topic available as well.[22][23]
A word of caution
The above is a somewhat random grab from publications on the topic of gravitational self-amplification, it’s not an exhaustive overview! Please also note that the effects theorized in the above references relate to either very large scales (for example galactic scales) and/or extreme environments such as neutron stars or black holes. Therefore, they are not something that would affect our everyday experience. Also, as always, if these theories turn out to be incorrect they will affect us even less:)
Gravitational (self-)amplification on steroids
And now the million dollar question: can we push a concept related to gravitational amplification to the limit and think of something that might inspire a breakthrough of astronomical proportions?
If we let our creativity run wild, what other mechanisms for gravitational amplification can we imagine? And wouldn’t it be cool if we could somehow leverage such a mechanism to advance in our own battle with gravity? For example, can we launch from the surface of the Earth and fly into space in a way that is somewhat easier than using giant fuel-devouring rockets?
Interested in this subject as a life long MSEE.
Musk is looking to technology in this area to achieve his latest goal of Mars travel. Will he live long enough for some help?
We thought Elon Musk aims to use somewhat more conventional technology for his Mars plans, but a scientific breakthrough could certainly help to achieve his ambitious plans, wouldn't that be cool?! Let's hope we all live long enough to see it!