Say that we wanted to send a probe into a black hole, perhaps hoping to see if it's actually a wormhole that might transport the probe elsewhere.

Upon approaching a black hole, the probe would undergo spaghettification:

In astrophysics, spaghettification (sometimes referred to as the noodle effect) is the vertical stretching and horizontal compression of objects into long thin shapes (rather like spaghetti) in a very strong non-homogeneous gravitational field; it is caused by extreme tidal forces. In the most extreme cases, near black holes, the stretching is so powerful that no object can withstand it, no matter how strong its components.

"Spaghettification", Wikipedia [references omitted]

This could be problematic because:

Inside or outside the event horizon

The point at which tidal forces destroy an object or kill a person will depend on the black hole's size. For a supermassive black hole, such as those found at a galaxy's center, this point lies within the event horizon, so an astronaut may cross the event horizon without noticing any squashing and pulling, although it remains only a matter of time, as once inside an event horizon, falling towards the center is inevitable. For small black holes whose Schwarzschild radius is much closer to the singularity, the tidal forces would kill even before the astronaut reaches the event horizon.

"Spaghettification", Wikipedia [references omitted]

Since spaghettification is a relativistic effect, I am unclear if its behavior might be different if the probe were to approach at relativistic speeds.


  1. Would a black hole's spaghettification of an approaching probe vary based on the probe's speed?

  2. If so, could this variation potentially be exploited to prevent a probe from being destroyed by a black hole's tidal forces?

  • 1
    $\begingroup$ Welcome to SE.Physics! I think I got the gist of what you wanted to ask, so I added in some context to help establish background. Please feel free to rollback the change if it doesn't match your intent, or else edit anything you'd like to improve. $\endgroup$
    – Nat
    Commented May 18, 2019 at 19:04

1 Answer 1


As per SR, only particles with no rest mass, like the photon can travel at the speed of light in vacuum, when measured locally.

Anything with rest mass, can only travel with speeds less then c, when measured locally in vacuum.

Now, normal matter, that does have rest mass, and travels at less then c, does get spaghettified.

You are asking whether if something would enter the black hole at c, would it get spaghettified. There is no possibility of any matter (with rest mass) to enter the hole at speed c.

Only particles with no rest mass, like the photon can do that, and photons do not get spaghettified (there are some effect on the photon by the hole, but that is not spaghettification).

Photons are elementary point particles, they do not have a spatial extension, nor an internal structure. They cannot be spaghettified. We characterize photons based on their frequency, wavefunction, energy, and other quantum numbers. Photons can get their wavelength altered by different phenomena (like expanding space, black hole gravitational effects etc.), but that is not spaghettification.

Spaghettification only refers to composite objects, and those can only travel at speeds less then c.

Now you are asking whether the entering speed will alter the effects of spaghettification, and the answer is :

  1. spaghettification will occur regardless of the entering speed for composite objects

  2. the extent to how much/ how fast they get spaghettified does matter and depend on their entering speed

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    $\begingroup$ Your final 18 words basically says “yes” but with no explanation of degree. The remainder of your answer may have applied to the question as originally worded but is now irrelevant. Could you edit your answer to focus on how much an extreme relativistic speed affects spaghettification. $\endgroup$ Commented May 21, 2019 at 5:34
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    $\begingroup$ The reason for 1. is that the effects of gravity causing spaghettification (stretching and squeezing) propagate at speed c, so you can't escape from them. The reason for 2. is because of how much time you spend in the region of space where the stretching and squeezing occurs. The faster you go, the less time you spend in the region of tidal effects, the less it affects you $\endgroup$ Commented Mar 12, 2021 at 16:31
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    $\begingroup$ @ÁrpádSzendrei This is useful information that belongs in the answer, not in a comment. $\endgroup$ Commented Mar 13, 2021 at 5:47

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