# Researchers calculate that sound has negative mass and negative gravity

Researchers claim sound waves do carry mass – gravitational mass. This implies that a sound wave not only is affected by gravity but also generates a tiny gravitational field. Our findings are valid for non-relativistic media as well, and could have intriguing experimental implications.

They claim that phonons might have negative mass and also have negative gravity.

Arxiv – The mass of sound

It is usually said that sound waves do not transport mass. They carry momentum and energy, and lead to temporary oscillations of the local mass density of any region they happen to pass through, but it is an accepted fact that the net mass transported by a sound wave vanishes.

A first indication that sound waves can in fact carry a nonzero net mass is contained in the results: using an effective point-particle theory, it was shown that phonons in zero-temperature superfluids have an effective coupling to gravity, which depends solely on their energy (or momentum) and on the superfluid’s equation of state. For ordinary equations of state, such a coupling corresponds to a negative effective gravitational mass: in the presence of an external gravitational field, such as that of Earth, a phonon’s trajectory bends upwards.

Now, this effect is completely equivalent to standard refraction in the form of Snell’s law: in the presence of gravity, the pressure of the superfluid depends on depth, and so does the speed of sound. As a result, in the geometric acoustics limit sound waves do not propagate along straight lines. Because of this, one might be tempted to dismiss any interpretation of this phenomenon in terms of “gravitational mass”.

They calculate the transported mass is in general quite small, of order M ∼ E/c2 s. For example, a very energetic phonon in superfluid helium-4 with momentum k ∼ 1 keV/c carries a mass roughly of order M ∼ 1 GeV/c2 , i.e. that of a single helium atom

It is possible to envision experimental setups where this effect could be detected. One possibility is to employ ultra-cold atomic or molecular gases. In these systems, in fact, not only might one be able to
achieve very small sound speeds and enhance the effect, but also use suitable trappings to simulate strong gravitational potentials.

Moreover, atomic clocks and quantum gravimeters can currently detect tiny changes in the gravitational acceleration of Earth, up to fractions of nm/s2. It is possible to imagine that, in a not too distant future, such techniques will reach the sensitivity necessary to detect the gravitational field associated with seismic w

### 37 thoughts on “Researchers calculate that sound has negative mass and negative gravity”

1. Using this sort of thing wouldn’t be tremendously useful for constructing some sort of anti gravity; either because the gravitational attraction produced by mass drops off fairly quickly, and that said mass, even if negative, would still be attracted to a positive mass like everything else.

2. I was under the impression that Hutchinson was a charlatan, and that all of his experiments were faked.

3. This is all theoretical and should be taken with a grain of salt!

4. negative mass – just think about it for a sec or so and realise the absurdity of that combination of words

5. Negative mass implies no inertia as well as negative gravity.

6. This is all theoretical and should be taken with a grain of salt!

7. negative mass – just think about it for a sec or so and realise the absurdity of that combination of words

8. Negative mass implies no inertia as well as negative gravity.

9. All this time I thought a wine glass shatters from a high pitch sound because of a resonant frequency, but now I find out that it’s torn apart by anti-gravity. 😉

10. So we should be able to build an anti-gravity drive. I wonder at what Decibel would gravity be cancelled.

11. All this time I thought a wine glass shatters from a high pitch sound because of a resonant frequency but now I find out that it’s torn apart by anti-gravity. 😉

12. So we should be able to build an anti-gravity drive. I wonder at what Decibel would gravity be cancelled.

13. so the wave is carried upwards slightly because matter under it is denser, isn’t it called “lift”? Should we say that planes are flying by means of wing anti-gravity effect?

14. so the wave is carried upwards slightly because matter under it is denser isn’t it called lift””? Should we say that planes are flying by means of wing anti-gravity effect?”””

15. Wouldn’t it be NEGATIVE inertia? Whatever that means.

16. Wouldn’t it be NEGATIVE inertia? Whatever that means.

19. Researcher ?? Ha… not even human…

20. Researcher ?? Ha… not even human…

21. Some of the woo-woo floating out there had it that sound was used to move megalithic blocks–Superman killed Darkseid with singing–and then there was poor Erich Zann and the Massa di Requiem per Shuggai

22. Some of the woo-woo floating out there had it that sound was used to move megalithic blocks–Superman killed Darkseid with singing–and then there was poor Erich Zann and the Massa di Requiem per Shuggai

23. Some of the woo-woo floating out there had it that sound was used to move megalithic blocks–Superman killed Darkseid with singing–and then there was poor Erich Zann and the Massa di Requiem per Shuggai

24. Some of the woo-woo floating out there had it that sound was used to move megalithic blocks–Superman killed Darkseid with singing–and then there was poor Erich Zann and the Massa di Requiem per Shuggai

25. Some of the woo-woo floating out there had it that sound was used to move megalithic blocks–Superman killed Darkseid with singing–and then there was poor Erich Zann and the Massa di Requiem per Shuggai

26. Researcher ?? Ha… not even human…

28. Wouldn’t it be NEGATIVE inertia? Whatever that means.

29. so the wave is carried upwards slightly because matter under it is denser, isn’t it called “lift”? Should we say that planes are flying by means of wing anti-gravity effect?

30. All this time I thought a wine glass shatters from a high pitch sound because of a resonant frequency, but now I find out that it’s torn apart by anti-gravity. 😉

31. So we should be able to build an anti-gravity drive. I wonder at what Decibel would gravity be cancelled.

32. This is all theoretical and should be taken with a grain of salt!

33. negative mass – just think about it for a sec or so and realise the absurdity of that combination of words

34. Negative mass implies no inertia as well as negative gravity.