Does dark matter contribute to my body mass?

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Discussion Overview

The discussion revolves around the question of whether dark matter contributes to an individual's body mass and how it interacts with normal matter. Participants explore the implications of dark matter's presence in the universe, particularly in relation to gravitational effects and measurements of mass.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant suggests that since dark matter is everywhere and clumps with regular matter due to gravity, some proportion of body mass could be attributed to dark matter.
  • Another participant counters that dark matter does not clump significantly except on cosmological scales and that it passes through the body without interaction, making its contribution to body mass negligible.
  • A further contribution emphasizes the small amount of dark matter present in the solar system, comparing it to the mass of a small asteroid, and discusses the density differences between normal matter and dark matter at various scales.
  • Some participants argue that even if dark matter were abundant, it would not affect mass measurements since it does not interact with normal matter in a way that would influence scales or inertia.
  • One participant elaborates that any potential effect of dark matter on weight would only arise from its accumulation within Earth, which would alter gravitational measurements, but calibrated scales would account for this.

Areas of Agreement / Disagreement

Participants express differing views on the interaction between dark matter and normal matter, with some asserting that dark matter has no measurable effect on individual mass, while others propose that its presence could influence gravitational measurements in a broader context. The discussion remains unresolved regarding the extent of dark matter's influence on personal mass.

Contextual Notes

Participants note limitations in current technology to measure dark matter's effects and the assumptions regarding its distribution and interaction with normal matter.

rootone
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No I'm not a particularly big person with a weight issue.
Somebody asked me this question and I don't know the answer, but somebody here will.

OK, it's now accepted that dark matter is everywhere in the Universe, it tends to clump with regular matter because all matter is subject to gravity, but there is a lot more of it than the normal matter.
So, some proportion of my body mass will be due to dark matter.
If the dark matter wasn't there, would I weigh less according my bathroom scales?
 
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Dark matter does not really clump except on cosmological scales. Any dark matter passing through your body just keeps right on going as though you weren't there. Also, there is so little dark matter in our solar system that the amount in the volume of your body would be unmeasurable with current technology.
 
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To give you an idea of how little dark matter there is in the solar system in total, it is about the same as that of a small asteroid. This may seem strange considering there is more dark matter in the universe than "normal: matter, but this has to do with distribution.

Planets are dense. The solar system taken as a whole is much less dense even though the total mass of the solar system is more than any given planet. The solar system as a whole is denser than a given volume of our local stellar neighborhood, even thought the combined mass of all the stars in the local neighborhood is more than that of the solar system. The density of the galactic disk is greater than that of the dark matter halo, but since the DM halo fills a much, much larger volume, the total mass of the dark matter halo is greater than that of the galactic disk.

It is the electromagnetic interaction of normal matter along with gravity that causes it to clump up like it does, and it is the lack of this electromagnetic interaction that keeps DM from clumping as densely.
 
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Janus said:
Planets are dense. The solar system taken as a whole is much less dense even though the total mass of the solar system is more than any given planet. The solar system as a whole is denser than a given volume of our local stellar neighborhood, even thought the combined mass of all the stars in the local neighborhood is more than that of the solar system. The density of the galactic disk is greater than that of the dark matter halo, but since the DM halo fills a much, much larger volume, the total mass of the dark matter halo is greater than that of the galactic disk.
Indeed, in that whole hierarchy, normal matter apparently has greater density than DM at every level, until the last one, the (outer) halo.
 
Even if there was a tonne of dark matter around, it wouldn't affect a measurement of your mass. It is just floating straight through you. If I push you, I will not feel the dark matter contributing to your inertia since it will just stay where it is while you move, since it is essentially not coupled to you at all. Likewise, it will not push down on the scales, since it goes straight through your body and straight through the scales. There is also no buoyant force or any such thing generated by it, since you are not displacing any dark matter. The only way it will change the measurement is by there being loads of dark matter collected in the Earth, which makes the effective gravitational mass of the Earth bigger. Then gravity on Earth will be a little bigger and you will register a larger weight on the scales as a result. Of course we would also have calibrated our scales to take this into account, so the marking on your scales would just have "10 kg" written in a slightly different position.
 
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