# Physics question.... **URL:** \ **Category:** Factual Questions\ **Created:** [June 15, 2003, 3:03am UTC](https://boards.straightdope.com/t/physics-question/181955 "2003-06-15T03:03:21Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![griffin77](https://avatars.discourse-cdn.com/v4/letter/g/3d9bf3/32.png) [@griffin77](https://boards.straightdope.com/u/griffin77)\ **Post date:** [June 15, 2003, 3:03am UTC](https://boards.straightdope.com/t/physics-question/181955/1 "2003-06-15T03:03:21Z")
We started building an aluminum ball out of ding dong wrappers, etc, here in our office to try to break the world’s record aluminum ball size. First, do you know what the current record is? Also, it came up that there may be a theoretical limit on the upper size of such an aluminum ball. The gravity would either cause a black hole, or start a thermonuclear reaction and change it into a different element. For hydrogen, iron, etc, we know that’s what happens, but what of aluminum? Or, there may not be an upper limit and the ball would just get bigger and bigger, and gravity would not be sufficient to cause either of these two scenarios. What would the eventual fate of such a ball be ? As this bet has now put an entire box of Ding Dongs at stake, we are hoping you can answer this question. Thanks… ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [June 15, 2003, 3:07am UTC](https://boards.straightdope.com/t/physics-question/181955/2 "2003-06-15T03:07:44Z")
Aluminum has mass, just like iron, hydrogen and every other element. If you have a ball of aluminum with sufficient mass to produce a gravitaional field stronger than the nuclear strong force, you’ve got a black hole. IIRC, about 3 solar masses is the crititcal mass for black hole formation. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [June 15, 2003, 3:23am UTC](https://boards.straightdope.com/t/physics-question/181955/3 "2003-06-15T03:23:33Z")
Aluminum has a smaller atomic number than iron, so a large enough ball of it (\> 1 stellar mass) would have nuclear reactions at its core, fusing aluminum into iron. It would look like a very atypical white dwarf star. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [June 15, 2003, 4:25am UTC](https://boards.straightdope.com/t/physics-question/181955/4 "2003-06-15T04:25:06Z")
> [@](#): > > \*Originally posted by Q.E.D. \* > \*\*IIRC, about 3 solar masses is the crititcal mass for black hole formation. \*\* Actually you need around 5-6 solar masses to form a black hole. > [@](#): > > _Origianlly posted by Lumpy:_ > Aluminum has a smaller atomic number than iron, so a large enough ball of it (\> 1 stellar mass) would have nuclear reactions at its core, fusing aluminum into iron. You need to get a fair deal bigger than our sun to fuse up to iron. IIRC the **Bad Astronomer** set me straight on this awhile back but I have a vague recollection that our sun would only get up to about silicon (just past half way to iron). Of course silicon is just the next step up from aluminum so our hypothetical aluminum ball might fuse. However, considering that for now we only have the mass of the earth to obtain material from and the earth. Even if it were 100% aluminum you’d still need something like 200,000+ more aluminum sized earths before you’d get fusion. NOTE: That is a guess based only upon the fact that the sun is around 333,000x the mass of the earth. Assuming stars can be smaller than our sun and that an all aluminum mass the size of the earth would weigh more than the earth I ball-parked my guess at 200,000. Whatever the real number though I think it is clear you’d need a LOT more Ding-Dong wrappers than you’ll ever be able to make here on earth or probably even with all the available aluminum in our solar system. ---
**Author:** ![griffin77](https://avatars.discourse-cdn.com/v4/letter/g/3d9bf3/32.png) [@griffin77](https://boards.straightdope.com/u/griffin77)\ **Post date:** [June 15, 2003, 6:20am UTC](https://boards.straightdope.com/t/physics-question/181955/5 "2003-06-15T06:20:20Z")
Yeah but with 10e22(+/- the odd sig. fig.) solar masses of aluminum out there in observable universe, ( based on rel. abundance of AL of 10e-5 and no. of atoms in obs. universe of 10e80) Though it shouldn’t be too hard to scrap together one or two S.M.'s worth for our record attempt, notwithstanding the absence of reliable relative abundance figures for no. of Ding-Dongs. Kit-Kats, Twinkies, etc. in the observable universe. More important as far the feasibilty of our record attempt (and the bet) are concerned is whether our ball will defintely start its fusion reaction, before turning into a black hole. If so (as these posters seem to suggest) will the guiness book of records still accept it as a aluminum foil ball if its core has started transforming into other elements… ---
**Author:** ![Fish](https://avatars.discourse-cdn.com/v4/letter/f/bc8723/32.png) [@Fish](https://boards.straightdope.com/u/Fish)\ **Post date:** [June 15, 2003, 7:24am UTC](https://boards.straightdope.com/t/physics-question/181955/6 "2003-06-15T07:24:43Z")
I don’t know if there is presently a record for “World’s Biggest Ding Dong Ball,” and if there is, I’d rename it. But here’s the link to the Guinness Book of World Records FAQ on setting new records. Evidently you can’t just do something exotic and expect to get listed: [http://www.guinnessworldrecords.com/faqs/FAQ\_Answer800.asp?ID=18](http://www.guinnessworldrecords.com/faqs/FAQ_Answer800.asp?ID=18) It’s a Flash-ready frames-on kind of website, so this direct link doesn’t get you into the rest of the site, so here is the answer, in part: > [@](#): > > If you wish to try something that hasn’t been done before or have already attempted a potential record then we’ll need to pass your suggestion on to our research department first. They’ll decide if it’s something that we’re interested in establishing as a new record category. If I were you, I’d lay off the Hostess snack-ball and become the first person to carve a replica of Connie Chung out of teakwood. Sure, it’ll take a little bit more effort, but I expect this whole thread is mostly chung-in-teak anyway. FISH What’s the atomic number of a Ding-Dong? ---
**Author:** ![Achernar](https://avatars.discourse-cdn.com/v4/letter/a/e274bd/32.png) [@Achernar](https://boards.straightdope.com/u/Achernar)\ **Post date:** [June 15, 2003, 7:59am UTC](https://boards.straightdope.com/t/physics-question/181955/7 "2003-06-15T07:59:52Z")
> [@](#): > > \*Originally posted by Fish \* > If I were you, I’d lay off the Hostess snack-ball and become the first person to carve a replica of Connie Chung out of teakwood. Sure, it’ll take a little bit more effort, but I expect this whole thread is mostly chung-in-teak anyway. -\_- I’m not sure exactly how people are getting the figures of 3 or 5-6 solar masses for black hole formation. It’s not true that any old gravitationally-bound object with that mass will collapse to a black hole. Are you saying that at the density of aluminum, the pressure at the core would be great enough to fuse aluminum? And that the core would fuse up to iron and then undergo supernova collapse to a black hole? Correct me if I’m wrong, but in stellar evolution, elements heavier than oxygen are formed by alpha-capture. So with no helium, how does aluminum fuse? On the other hand, a ball of aluminum at normal density (2700 kg/m[sup]3[/sup]) with a mass of 82.6 Million M[sub]SUN[/sub] would be a black hole already. ---
**Author:** ![Early\_Out](https://avatars.discourse-cdn.com/v4/letter/e/6f9a4e/32.png) [@Early\_Out](https://boards.straightdope.com/u/Early_Out)\ **Post date:** [June 15, 2003, 1:43pm UTC](https://boards.straightdope.com/t/physics-question/181955/8 "2003-06-15T13:43:47Z")
Maybe you can set the record for “Most Ding-Dongs Eaten Without Becoming Morbidly Obese.” Or is it too late for that already? ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [June 15, 2003, 2:17pm UTC](https://boards.straightdope.com/t/physics-question/181955/9 "2003-06-15T14:17:38Z")
> [@](#): > > \*Originally posted by Whack-a-Mole \* > **Actually you need around 5-6 solar masses to form a black hole.** No. > [@](#): > > If this minimum mass is greater than the maximum mass of a neutron star (about 3 solar masses), then the accreting object can be safely assumed to be a black hole. From [this page.](http://www.astro.yale.edu/bailyn/bhc.html) and > [@](#): > > These compact objects are widely believed to be black holes, since the maximum mass of a neutron star allowed by general relativity is only about 3 solar masses. From [here.](http://www.eps.org/aps/meet/APR02/baps/abs/S4030003.html) and finally > [@](#): > > From observations in July, Berkeley astronomer Alex Filippenko and graduate students Thomas Matheson and Aaron Barth estimated a minimum mass of five times that of the sun–considerably above the limit of 3.2 solar masses and thus presumably a black hole. From [here.](http://www.berkeley.edu/news/berkeleyan/1995/1108/another.html) _[fixed coding]_ ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [June 15, 2003, 2:20pm UTC](https://boards.straightdope.com/t/physics-question/181955/10 "2003-06-15T14:20:36Z")
> [@](#): > > \*Originally posted by Achernar \* > **It’s not true that any old gravitationally-bound object with that mass will collapse to a black hole.** Yes, it is. See my post above. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [June 15, 2003, 2:34pm UTC](https://boards.straightdope.com/t/physics-question/181955/11 "2003-06-15T14:34:15Z")
And before some wiseguy pops in saying there are many stars with masses far larger than 3.20 M[sub]solar[/sub], I am aware of this. The reason such stars don’t collapse into black holes is because the pressure of fusion heat acts to partially counteract gravity. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [June 15, 2003, 3:24pm UTC](https://boards.straightdope.com/t/physics-question/181955/12 "2003-06-15T15:24:03Z")
[QUOTE] \*Originally posted by Q.E.D. \* \*\*No. From [this page.](http://www.astro.yale.edu/bailyn/bhc.html) and [quote] These compact objects are widely believed to be black holes, since the maximum mass of a neutron star allowed by general relativity is only about 3 solar masses.From [here.](http://www.eps.org/aps/meet/APR02/baps/abs/S4030003.html)and finally > [@](#): > > From observations in July, Berkeley astronomer Alex Filippenko and graduate students Thomas Matheson and Aaron Barth estimated a minimum mass of five times that of the sun–considerably above the limit of 3.2 solar masses and thus presumably a black hole.From [here.](http://www.berkeley.edu/news/berkeleyan/1995/1108/another.html) \*\* I don’t see how your links suggest a 3 solar mass black hole is possible. It just suggests that a neutron star is limited to about 3 solar masses. > [@](#): > > “Astronomical theory says that these extremely low-mass black holes should exist, and now we’ve finally found at least two,” says Dawn Gelino, a postdoctoral fellow at the UCSD Center for Astrophysics and Space Sciences. “These two finds take us near the uncertain boundary between a neutron star and a black hole.” > > Today in Albuquerque, NM, at the 200th meeting of the American Astronomical Society (AAS), Gelino presents results on a candidate black hole system with a tentative mass of just 5.25 solar masses, using observational data from the 4-meter Blanco telescope at Cerro Tololo Inter-American Observatory in Chile. > > \ > > Last month, Gelino submitted results to the Astrophysical Journal Letters that identify a 4.25-solar mass black hole in the system known as J0422+32, using data from the 3.5-meter telescope at Apache Point Observatory in New Mexico. > > \ > > The nature of the compact object is based upon its mass. The generally accepted maximum mass of a neutron star is between 3-3.2 solar masses. Therefore, if an object is found with a mass larger than this and it is very compact, it is designated as a black hole. > > SOURCE: [National Optical Astronomy Observatory](http://www.noao.edu/outreach/press/pr02/pr0205.html) I assume it is from that last bit that you get your lower limit of 3 solar masses from but there seems to be a gray area here. I think we are forgetting something though. The final mass of the black hole at a minimum needs to be 3+ solar masses but it likely has to be formed from a MUCH larger star. In the star’s death throes it will eject a great deal of its mass in a supernova explosion. If it is large enough what remains may form a black hole. > [@](#): > > Black holes are believed to be the end result of a very massive star’s life. Their progenitor stars are thought to have masses greater than about 25 times that of the Sun. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [June 15, 2003, 3:29pm UTC](https://boards.straightdope.com/t/physics-question/181955/13 "2003-06-15T15:29:06Z")
> [@](#): > > \*Originally posted by Fish \* > **I don’t know if there is presently a record for “World’s Biggest Ding Dong Ball,” and if there is, I’d rename it. But here’s the link to the Guinness Book of World Records FAQ on setting new records. Evidently you can’t just do something exotic and expect to get listed:** True but I’d wager if you made a Ding-Dong Ball big enough to start its own fusion reaction then the Guiness Book of World Records would probably manage to fit you in somewhere for something. 😃 ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [June 15, 2003, 3:34pm UTC](https://boards.straightdope.com/t/physics-question/181955/14 "2003-06-15T15:34:39Z")
[QUOTE] \*Originally posted by Whack-a-Mole \* **I don’t see how your links suggest a 3 solar mass black hole is possible. It just suggests that a neutron star is limited to about 3 solar masses.** [/quote] Well, duh. Because the next stage after a neutron star is further gravitational collapse into a black hole. At the neutron star stage, the only thing keeping the object from collapsing is the nuclear strong force. Once _that_ has been overwhelmed, there is noting to prevent further collapse into a black hole. > [@](#): > > \*Originally posted by Whack-a-Mole \* > \*\*I assume it is from that last bit that you get your lower limit of 3 solar masses from but there seems to be a gray area here. > > I think we are forgetting something though. The final mass of the black hole at a minimum needs to be 3+ solar masses but it likely has to be formed from a MUCH larger star. In the star’s death throes it will eject a great deal of its mass in a supernova explosion. If it is large enough what remains may form a black hole. \*\* Yes, and the reason for this is that large, dying stars go supernova before their nuclear furnace is extinguished, and in doing so expell a huge percentage of their mass. The infusible remains must be greater than 3.2 solar masses in order for a black hole to be formed. ---
**Author:** ![Ring](https://avatars.discourse-cdn.com/v4/letter/r/6a8cbe/32.png) [@Ring](https://boards.straightdope.com/u/Ring)\ **Post date:** [June 15, 2003, 4:18pm UTC](https://boards.straightdope.com/t/physics-question/181955/15 "2003-06-15T16:18:41Z")
> [@](#): > > \*Originally posted by Q.E.D. \* > \*\*Aluminum has mass, just like iron, hydrogen and every other element. If you have a ball of aluminum with sufficient mass to produce a gravitaional field stronger than the nuclear strong force, you’ve got a black hole. IIRC, about 3 solar masses is the crititcal mass for black hole formation. \*\* Its electron and neutron degeneracy pressure that respectively stabilizes a white dwarf or neutron star, not the strong force. Who’s going to consume all these Ding Dongs? I fear the Elbonians would no longer be standing in mud. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [June 15, 2003, 4:57pm UTC](https://boards.straightdope.com/t/physics-question/181955/16 "2003-06-15T16:57:06Z")
Since the wrapper of the Ding-Dongs has far less mass than the product itself, I suspect that the people eating them would reach black hole status first. Given how many would have to be consumed in a person’s lifetime, weight loss techniques would be futile. **Early Out** ’s concern about “morbidly obese” is understated. If the product was left uneaten and thrown out, the landfill would go first. Sort of handy: a landfill and a black hole all in one. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 15, 2003, 6:09pm UTC](https://boards.straightdope.com/t/physics-question/181955/17 "2003-06-15T18:09:41Z")
> [@](#): > > I don’t see how your links suggest a 3 solar mass black hole is possible. It just suggests that a neutron star is limited to about 3 solar masses. So if you take a maximum-mass neutron star and add a little mass to it, what do you get? So far as we know, there’s no stage between neutron star and black hole. So you can have a black hole with mass that low. Which isn’t really relevant. If we assume normal aluminum density, then we get **Achernar** ’s answer. In actual practice, of course, the core of a very large alumiball would compress, so we would get a black hole quicker than that. But I have no idea what the equation of state of aluminum is at such extreme pressures, and frankly, I’m not sure I want to know (even I have to draw the line on useless knowledge _somewhere_). ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [June 15, 2003, 9:04pm UTC](https://boards.straightdope.com/t/physics-question/181955/18 "2003-06-15T21:04:16Z")
> [@](#): > > \*Originally posted by Chronos \* > \*\*So far as we know, there’s no stage between neutron star and black hole. \*\* What about a Quark Star (sometimes called a Strange Star)? IIRC they are consider an even more dense star that might be a stable star between a neutron star and a black hole. Actually, a quick Google search turned up this article ( [http://www.nature.com/nsu/020408/020408-8.html](http://www.nature.com/nsu/020408/020408-8.html) ) that suggests a quark star might have been found (although it is open to debate whether or not it really is one). Still, the notion of a quark star seems to be valid in scientific circles. ---
**Author:** ![griffin77](https://avatars.discourse-cdn.com/v4/letter/g/3d9bf3/32.png) [@griffin77](https://boards.straightdope.com/u/griffin77)\ **Post date:** [June 16, 2003, 2:57am UTC](https://boards.straightdope.com/t/physics-question/181955/19 "2003-06-16T02:57:32Z")
Hmm… still no nearer an answer on the ulimate fate of record attempt, and the views are becoming heated on both sides on the argument here in the office (there is a genuine, non-hypothetical box of tasty foil wrapped snacks at stake after all). Will the aluminum form a black hole before any other effects (fusion, super-nova, etc.) take hold ? A poster on a related thread said this: > [@](#): > > \*Originally posted by Exapno Mapcase \* > \*\*A star that is in the last throes of its existence will collapse to the object that its mass dictates. It will become a dwarf star, a neutron star, or a black hole. But this is the outcome of a long process of events. It doesn’t just suddenly happen as the result of the passing of a threshold. > > [http://www.rdrop.com/users/green/school/form.htm](http://www.rdrop.com/users/green/school/form.htm) \*\* Will the different thresholds on this web-site apply to us ? Will the fusion component of equation which stops a star collapsing, do the same for our ding-dong wrappers ? Will aluminium fuse at all ? BTW - On the issue of the side-bet (what the world record is for the biggest foil ball). Just because a record is not on [www.guinnessworldrecords.com](http://www.guinnessworldrecords.com) doesn’t mean it doesn’t exist, if you read the small print the database online only holds a small selection of the records in the book. We’re pretty sure there is an existing record, though we can’t find out what it is… ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [June 16, 2003, 3:47am UTC](https://boards.straightdope.com/t/physics-question/181955/20 "2003-06-16T03:47:56Z")
> [@](#): > > \*Originally posted by griffin77 \* > \*\*Will the aluminum form a black hole before any other effects (fusion, super-nova, etc.) take hold ? > > \ > > Will the fusion component of equation which stops a star collapsing, do the same for our ding-dong wrappers ? Will aluminium fuse at all ?\*\* Your Ding-Dong ball will have to pass through various stages before a black hole forms (unless you keep many smaller masses of aluminum foil separate and then bring them together all at once such that their combined mass could form a black hole). However, if you just keep adding aluminum wrappers to your ball you wold eventually get enough to start a fusion reaction. After that you proceed through a few explosive consequences of continuing to add mass till you get your black hole. Of course, once the fusion starts your Ding-Dong ball will no longer be just aluminum as it would start fusing into other elements (this ultimately stops at iron as fusing beyond that takes mroe energy than it produces). Your ball will resist collapse into a black hole via fusion and a few other mechanisms (e.g. neutron degeneracy pressure) before collapsing into a black hole. Essentially your ball will want to explode and will try very hard to do so. [Next page](https://boards.straightdope.com/t/physics-question/181955.md?page=2)