<p>It could do serious damage if things were just right.</p>

<p>Three solar masses of energy is about 5x10<sup>47</sup> Joules.  1 AU is about 1.5x10<sup>13</sup> cm. The area of the sphere is thus about 4x10<sup>27</sup> cm<sup>2</sup>.  That's a flux of 10<sup>20</sup> joules cm<sup>-2</sup>.  That's plenty of energy to do damage...if it can couple to you.</p>

<p>The strain of the GW measured at Earth is around 10<sup>-22</sup>.  Strain drops off as the inverse distance, and the ratio of a gigaparsec to an AU is about 10<sup>14</sup>, so the strain at 1AU from the merger would be about 10<sup>-8</sup>. By itself, this would probably not harm you.</p>

<p>But it's not a simple one-time strain, it is oscillating with the orbital frequency of the merging black holes, and anything which had a physical resonance at that frequency could pick up energy, possibly significant energy, from the GW fields.</p>

<p>(Note that this depends on orientation. The mechanical resonance needs to align with the GW, and GWs are not emitted in all directions, so you'd want (or, perhaps, not want!) to be in the plane of the merger.)</p>

<p>The argument that GWs can't deposit energy is plainly wrong -- if it were true, LIGO couldn't detect them! -- but if you believed that, you were in superb company: It took Einstein decades before he became convinced that GWs actually carried energy!</p>

CC BY-SA 4.0
2018-07-19T21:35:20.870Z
The strain of $10^{-8}$ is the key thing, so you would get about 20nm taller and 10nm narrower and then a tenth or so of a second later, the opposite, and that would be repeated for 10 or 20 cycles at increasing frequency before stopping. It's hard to see that that would do much to a human directly. A very rigid crystalline structure that happened to resonate with the signal might see something more dramatic. What's going to be much more noticeable is the effects on accretion disk(s) much closer to the BH. That would easily produce a very intense burst of X-rays which might not be so healthy.
Steve Linton
CC BY-SA 4.0
2018-07-19T20:34:39.463Z
2019-09-02T01:03:04.190Z
2019-09-02T01:03:04.190Z
Mark Olson
<p>The recent <a href="https://www.ligo.caltech.edu/news/ligo20170927" rel="noreferrer">4th discovery of gravitational waves</a> where the black hole masses were 31 and 25 times the mass of the sun, and they released 3 solar masses of energy as gravitational waves, made me wonder what would it feel like to be orbiting this binary black hole system on a planet at 1AU when the merger happened? </p>

CC BY-SA 3.0
2017-09-28T05:23:26.887Z
This article addresses your question, written by a physicist.   https://www.forbes.com/sites/briankoberlein/2016/02/13/could-gravitational-waves-ever-be-strong-enough-to-feel/#6c7b92e5b02f   And here's a very similar question:   https://physics.stackexchange.com/questions/235285/how-strong-were-the-gravitational-waves-that-ligo-detected-at-the-source
userLTK
CC BY-SA 3.0
2017-09-28T09:30:14.637Z
answers at physics are very different from @t.sand 's one...
J. Chomel
CC BY-SA 3.0
2017-09-28T15:54:43.843Z
The answers in the physic stackexchange is completely unsatisfactory. The ones dealing with energy don't even mention that gravity is so weakly interacting that the 3 solar mass of gravitational energy itself would do very little to a human because due to the size of a human and the size of the gravitational constant. The accepted answer is pretty useless given that spacetime distortions is nothing like normal compression and stretching and there is no proof that smooth gravitational waves distorting matter can be damaging to humans at 0.01% human size.
A. C. A. C.
CC BY-SA 3.0
2018-04-06T05:33:21.387Z
I'm amazed that no one picks up @A.C.A.C.'s point that the GWs are ripples in *spacetime*, and this distortion is fundamentally different to compression or stretching of objects in ordinary space. The other thing overlooked is that the GW travels at the speed of light: it's impossible to "feel" a ripple at that speed.
Chappo Hasn't Forgotten
CC BY-SA 4.0
2019-09-02T00:10:02.850Z
similar question in Physics SE: [How would a passing gravitational wave look or feel?](https://physics.stackexchange.com/q/338912/83380)
uhoh
<black-hole><gravitational-waves>
What would it feel like to be orbiting near a merging black hole?
joseph.hainline
# What would it feel like to be orbiting near a merging black hole?

(Asked by: username_0 on 2017-09-27)

The recent [4th discovery of gravitational waves](https://www.ligo.caltech.edu/news/ligo20170927) where the black hole masses were 31 and 25 times the mass of the sun, and they released 3 solar masses of energy as gravitational waves, made me wonder what would it feel like to be orbiting this binary black hole system on a planet at 1AU when the merger happened?

**Tags:** black-hole, gravitational-waves

> **Comments:**
> **username_1**: This article addresses your question, written by a physicist.   https://www.forbes.com/sites/briankoberlein/2016/02/13/could-gravitational-waves-ever-be-strong-enough-to-feel/#6c7b92e5b02f   And here's a very similar question:   https://physics.stackexchange.com/questions/235285/how-strong-were-the-gravitational-waves-that-ligo-detected-at-the-source  
> **username_2**: answers at physics are very different from @t.sand 's one...  
> **username_3**: The answers in the physic stackexchange is completely unsatisfactory. The ones dealing with energy don't even mention that gravity is so weakly interacting that the 3 solar mass of gravitational energy itself would do very little to a human because due to the size of a human and the size of the gravitational constant. The accepted answer is pretty useless given that spacetime distortions is nothing like normal compression and stretching and there is no proof that smooth gravitational waves distorting matter can be damaging to humans at 0.01% human size.  
> **username_4**: I'm amazed that no one picks up @A.C.A.C.'s point that the GWs are ripples in *spacetime*, and this distortion is fundamentally different to compression or stretching of objects in ordinary space. The other thing overlooked is that the GW travels at the speed of light: it's impossible to "feel" a ripple at that speed.  
> **username_5**: similar question in Physics SE: [How would a passing gravitational wave look or feel?](https://physics.stackexchange.com/q/338912/83380)  

---

## 1 answers

### Answer by username_6 on 2018-07-19. Score: 4

It could do serious damage if things were just right.

Three solar masses of energy is about 5x1047 Joules. 1 AU is about 1.5x1013 cm. The area of the sphere is thus about 4x1027 cm2. That's a flux of 1020 joules cm-2. That's plenty of energy to do damage...if it can couple to you.

The strain of the GW measured at Earth is around 10-22. Strain drops off as the inverse distance, and the ratio of a gigaparsec to an AU is about 1014, so the strain at 1AU from the merger would be about 10-8. By itself, this would probably not harm you.

But it's not a simple one-time strain, it is oscillating with the orbital frequency of the merging black holes, and anything which had a physical resonance at that frequency could pick up energy, possibly significant energy, from the GW fields.

(Note that this depends on orientation. The mechanical resonance needs to align with the GW, and GWs are not emitted in all directions, so you'd want (or, perhaps, not want!) to be in the plane of the merger.)

The argument that GWs can't deposit energy is plainly wrong -- if it were true, LIGO couldn't detect them! -- but if you believed that, you were in superb company: It took Einstein decades before he became convinced that GWs actually carried energy!

> **Comments:**
> **username_7**: The strain of $10^{-8}$ is the key thing, so you would get about 20nm taller and 10nm narrower and then a tenth or so of a second later, the opposite, and that would be repeated for 10 or 20 cycles at increasing frequency before stopping. It's hard to see that that would do much to a human directly. A very rigid crystalline structure that happened to resonate with the signal might see something more dramatic. What's going to be much more noticeable is the effects on accretion disk(s) much closer to the BH. That would easily produce a very intense burst of X-rays which might not be so healthy.  

---

