Talk:Spaghettification

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(William M. Connolley 17:33, 5 Sep 2004 (UTC)) This page might benefit from a link to Image:Tidal-forces-calculated.png.

Who's got a picture of an astronaut being spaghettified?? 204.52.215.99 15:12, 28 March 2007 (UTC)

I'm sorry about making seemingly irrational changes and saying it was not needed; in my browser there has recently been a change meaning that the images are placed neatly below each other at all times. I thought this was a welcomed new wikipeida feature. [[User:Sverdrup|❝Sverdrup❞]] 20:14, 6 Sep 2004 (UTC)

They line up neatly for me too. Perhaps it's a browser issue?(firefox 0.9.3). Mind you even if it is, it's clearly better to go with Bryan so that it looks good for everyone. Theresa Knott (Nate the Stork) 20:25, 6 Sep 2004 (UTC)
Ah, I see. I'm using Mozilla 1.8a1 with the "Classic" Wikipedia skin, if you're curious. I would also welcome a new Wikipedia feature like that. :) Bryan 20:27, 6 Sep 2004 (UTC)

Contents

[edit] Sure of it?

Eventually, close to the singularity, they become large enough to tear atoms apart. -Anon

You make a good point. No come to think of it I'm not sure. I've reworded the text. Theresa Knott (The torn steak) 12:26, 17 Oct 2004 (UTC)


[edit] Accelerated Towards?

Gravity is fixed acceleration. Even going down a black holes throat. The space/frames of refrence are going to elongate, and light is going to slow down to the outside observe.

but the acceleration due to gravity is the same. Due to the acceleration, your velocity increases, and due to the velocity increase, as you go faster, your distance down the hole increases.

This is all that happened when the Apple fell from the tree.

Which theory of gravity are you working with?

Artoftransformation 17:15, 9 November 2005 (UTC)

I spent a while pondering your comment, trying to think of a way to ask exactly what you're talking about without sounding patronizing. I couldn't think of one, sorry. What are you talking about, specifically?

This doesn't have to bring in time dilation or relativistic velocity or anything silly at all, this is basic physics alone. Of course at any specific distance, gravitational acceleration is fixed, but that's really the entire point. You don't usually notice tidal forces (our ocean being an obvious exception), this is just an extreme case since black holes are relatively small so the differences in acceleration are magnified, and relatively huge stuff gets sucked into them.

Example: Pick up a ball bearing and drop it, it falls at ~9.8m/s^2 because you're standing around 6000km away from the center of the Earth. Get a really tall ladder and drop another ball bearing from 3000km above the surface of the earth, and it only falls at 4.9m/s^2. Now, take a 3000km-long foam noodle, hold it by one end so the bottom end is a few hundred meters above the Earth's surface, and drop it. Ignoring air resistance, what happens? After the first second, the bottom end has fallen 4.9 meters, while the top end has fallen 2.45; it stretches out to compensate for this difference. Earth's gravity might not even be sufficiently strong for the sake of this example - pretend there's a big metal ball at both the top and bottom ends, whatever. The point is that with black holes, you don't need to use foam rubber; their high mass/density by definition means that there's going to be enough free space to fall in for the tidal forces to become strong enough to rip nearly anything apart (ie. tidal force drops off much faster than gravitational force, and we start running into dirt and stuff by the time we get within 6000km or so of the center of the Earth's mass).

Just as a totally trivial, but at least possible, example (physics is not my forte), take a black hole of a thousand solar masses. Its Schwarzschild radius is 2952m, so pretend we're somehow hovering (100000m-2952m) above it, and that we're 2m tall. Get out of your still-hovering spaceship and fall. Yeah, it'll only take you 1.226x10^-4 sec to splatter, but in that time, based only on the original disparity in acceleration due to the difference in distance of your head and feet, your head will have fallen 4m less than your feet. Of course this also assumes you're basically a person-shaped pile of dust, but with this sort of force (stretching 4 meters in 100 microseconds), I don't imagine the human body would put up much resistance at all. In reality you'd be stretched much farther, due both to your height becoming more relatively significant compared to the decreasing distance, and your absolute height increasing the entire time you fell.

The second component of spaghettification has nothing to do with tidal force per se - like the article's top diagram shows, if you have something that is wide (not difficult when you drop a star into a black hole that's a few km across), its edges will be pushed together, moreso at the bottom, because their definition of "down" is different. I don't know if this would normally work fast enough to push the top and bottom apart from each other, but it'd at least make the object thinner. Straker 11:39, 11 November 2005 (UTC)

Whoops. Okay, so my quick example obviously entails going FTL. Sillily enough, this doesn't break anything in the concept of spaghettification itself, so if this happens to bother you, play with the numbers some (a thousand solar masses is kind of a weird mass anyways, should usually be much heavier or much lighter). Straker 12:10, 12 November 2005 (UTC)

[edit] Can't spaghettification be explained much more simply?

It looks to me like this article is overcomplicated and spaghettification can be explained in under 30 lines, plus possibly 1 very simple diagram (using Newtonian gravity):

  • Gravitational pull is inversely proportional to the square of distance.
  • So the pull on the near side of an object is greater than the pull on the far side.
  • That means the near side wants to accelerate faster than the far side towards the source of the gravity field.
  • This difference in acceleration creates tension between the 2 sides of the object. The tension is proportional to 2 factors: the length of the object in the direction pointing towards the gravity source; the strength of the gravitational force.
  • For "normal" gravity fields, like Earth's, the effect is negligible if the object is smaller than a large asteroid. But in an extremely strong gravity fields, such as a black hole's, the tension can become enough to stretch the object and eventually pull it apart.
  • Spaghettification contains a positive feedback loop - as the "victim" gets longer, the tensile force increases, etc.
  • If the gravity source is very small (e.g. black hole) and the "victim" is relatively large, the stretching is increased by lateral compression since the sides of the "victim" are falling along converging paths. If the lateral compression actually increases the "victim's" length, it also increases the tensile force, etc.

Or am I missing something?

If I'm right and the article can be simplified, we can use the extra space for additional aspects, e.g.: any new features added by general relativity; spahettification eventually destroys atoms and even sub-atomic particles falling into black holes, because as the distance from the black hole decreases the gravitational pull increases very fast (inverse square law) and the difference in distance between the leading and trailing edges of the "victim" becomes a large fraction of the distance to the black hole; what happens when 2 black holes meet.Philcha 18:55, 16 March 2007 (UTC)


could it be explained as like the shape of a rain drop?

[edit] Does the "tidal forces" diagram help non-specialist readers?

I doubt whether the diagram "tidal forces acting on a spherical body in a gravitational field" helps non-specialist readers. To understand it I think readers would need to understand (a) the basic principles of tidal forces; (b) how to split forces into components and re-combine them; (c) the convention that length of arrow is proportional to strength of force.Philcha 13:30, 28 March 2007 (UTC)

[edit] Should the article mention another kind of spaghettification?

The process where a computer program turns to spaghetti code. Interestingly enough, it is also an indication that the program is falling into a black hole. (It didn't look like there was an appropriate place to mention this in the article though.) —The preceding unsigned comment was added by EmptyString (talk • contribs) on 22:54, 19 April 2007.

I've added a disambiguation message about this. --Christopher Thomas 23:01, 19 April 2007 (UTC)

[edit] How about a "complex math analysis" or something?

You know, something involving general relativity, calculus, tensors, the works. Practically every other astrophysics, quantum physics, and physics article in general delves into the enormously complex math behind it, so why not this one? :) -Matt 01:26, 19 June 2007 (UTC)

My math isn't good enough! More importantly, how many readers would it help? People who understand general relativity, calculus, tensors, the works don't look up subjects like Spaghettification in Wikipedia.Philcha 02:28, 27 June 2007 (UTC)

[edit] Remove "tidal forces" diagram?

A while ago I wrote in tis Talk page: "I doubt whether the diagram "tidal forces acting on a spherical body in a gravitational field" helps non-specialist readers. To understand it I think readers would need to understand (a) the basic principles of tidal forces; (b) how to split forces into components and re-combine them; (c) the convention that length of arrow is proportional to strength of force." Nobody has argued in favour of keeping the diagram. I also note that the diagram's caption contains a serious error, because the source page for the image says that the gravity source is (counter-intuitively) to the right. I propose to remove the diagram.Philcha 23:44, 13 July 2007 (UTC)

Just fixed two of the four issues right now. The other two (splitting forces and general understanding of tidal forces) are probably a bit much to completely explain in an image caption, but we do have a separate article on tidal forces and there's an image farther down in the article that IMO dovetails well with this one on explaining where the compression and stretching comes from. I think it's a keeper, myself. Though perhaps we should rotate it to match the vertical orientation of the other image, having gravity acting vertically is more intuitive. Bryan Derksen 01:10, 14 July 2007 (UTC)

[edit] another reference

Found this comment in the article, but it seemed more appropriate here. Gamaliel (talk) 20:30, 28 February 2008 (UTC)

(Another reference is needed here, for the word was popularized and put into the public mind via a Discovery Channel program on black holes around 2001, in which a physicist graphically described the term)