Star crust 10 billion times stronger than steel, physicists find

May 6, 2009
ROSAT HRI image of Puppis A. Image: NASA.

(PhysOrg.com) -- Research by a theoretical physicist at Indiana University shows that the crusts of neutron stars are 10 billion times stronger than steel or any other of the earth's strongest metal alloys.

Charles Horowitz, a professor in the IU College of Arts and Sciences' Department of Physics, came to the conclusion after large-scale molecular dynamics were conducted at Indiana University and Los Alamos National Laboratory in New Mexico. The research will appear Friday (May 8) in Physical Review Letters.

Exhibiting extreme gravity while rotating as fast as 700 times per second, are massive stars that collapsed once their cores ceased nuclear fusion and energy production. The only things more dense are , as a teaspoonful of neutron star matter would weigh about 100 million tons.

Scientists want to understand the structure of neutron stars, in part, because surface irregularities, or mountains, in the crust could radiate and in turn may create ripples in space-time. Understanding how high a mountain might become before collapsing from the neutron star's , or estimating the crust's breaking strain, also has implications for better understanding star quakes or magnetar giant flares.

"We modeled a small region of the neutron star crust by following the individual motions of up to 12 million particles," Horowitz said of the work conducted through IU's Nuclear Theory Center in the Office of the Vice Provost for Research. "We then calculated how the crust deforms and eventually breaks under the extreme weight of a neutron star mountain."

Performed on a large computer cluster at Los Alamos National Laboratory and built upon smaller versions created on special-purpose molecular dynamics computer hardware at IU, the simulations identified a neutron star crust that far exceeded the strength of any material known on earth.

The crust could be so strong as to be able to elicit gravitational waves that could not only limit the spin periods of some stars, but that could also be detected by high-resolution telescopes called interferometers, the modeling found. An online version of the research paper, "The breaking strain of neutron star crust and gravitational waves," can be found at arxiv.org/PS_cache/arxiv/pdf/0904/0904.1986v1.pdf .

"The maximum possible size of these mountains depends on the breaking strain of the neutron star crust," Horowitz said. "The large breaking strain that we find should support mountains on rapidly rotating neutron stars large enough to efficiently radiate gravitational waves."

Because of the intense pressure found on neutron stars, structural flaws and impurities that weaken things like rocks and steel are less likely to strain the crystals that form during the nucleosynthesis that occurs to form neutron star crust. Squeezed together by gravitational force, the crust can withstand a breaking strain 10 billion times the pressure it would take to snap steel.

Provided by Indiana University (news : web)

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26 comments

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Alexa
2.9 / 5 (21) May 06, 2009
From AWT follows, such crust is solid and brittle only from external perspective (resistance toward zero and 2nd derivation of location vs. time), whereas inside it's formed superfluos material (resistance toward 1st derivation of location vs. time). This is an result of extreme inertial forces, which are applied here.

We can met with similar behavior at the case of boson condensates, which can be manipulated by external magentic field from outside, when they appear quite sticky, whereas from inside they're superconductive.

Every close sectarian community or society behaves by the same way: from outside it's heavilly censored and conservative against changes, whereas from inside it's totalitarian and ideas are spreading here without opposition.

A quite interesting stuff, isn't it?
omatumr
1 / 5 (9) May 06, 2009
SUN ALSO HAS RIGID IRON !

Professor Charles Horowitz and PhysOrg readers may be interested in the rigid, iron-rich structures that the SOHO and TRACE spacecrafts observed in the Sun.

These are shown in Figure 1 (page 2) of a paper published in Physics of Atomic Nuclei 69, number 11, pp. 1847-1856 (Nov 2006); Yadernaya Fizika 69, number 11, (Nov 2006); PAC: 96.20.Dt DOI: 10.1134/S106377880611007X
http://arxiv.org/...609509v3

With kind regards,
Oliver K. Manuel
http://www.omatumr.com
jldb
3.5 / 5 (4) May 06, 2009
These calculations make a strong assumption regarding interparticle interactions -- and all their results follow from this. Essentially
electrons are assumed to play no significant role other
than screening of interactions between ions. In my option, at these densities, 10^13 g / cm^3 (that's ten thousand billion times more dense than water) this assumption is pretty ridiculous.
Shootist
5 / 5 (4) May 06, 2009
"Star crust 10 billion times stronger than steel, physicists find"

geez, we've known this since Larry Niven's "Neutron Star" (Oct '66) and episode 35 of Star Trek's "The Doomsday Machine" (Oct '67) written by Norman Spinrad.
thales
3.7 / 5 (3) May 06, 2009
Sorry Alexa I meant to give you a higher rating. You had some interesting points.

This neutronium has some extreme properties. I wonder if neutrinos can pass through it.
JayVenter
not rated yet May 06, 2009
"a teaspoonful of neutron star matter would weigh about 100 million tons."

i take it this is the weight of the matter on the star and not on earth ?
what i mean to say is, its strength is due to the extreme gravity and not because its a special kind of matter or anything ?
sorry if i sound stupid but i dont know much about physics..
QubitTamer
4 / 5 (1) May 06, 2009
This to me is further proof that space-time does not form a fabric as is popularly described and theorized. Because how could such dense and fast spinning objects not separate / rip from the region of space around them? Not thinking 2 dimensionally here, even though the stress forces on space-time would seem to be highest at the equator plane where the angular momentum relative to space would be highest.

Or is it shown somewhere that space-time can be infinitely twisted and stretched out in the spherical region around black holes, neutron stars, quasars etc?

Bear in mind my field is computer science / quantum cryptography so i am out of my lane here...
Alizee
May 06, 2009
This comment has been removed by a moderator.
El_Nose
not rated yet May 06, 2009
hey qubit -- i believe you are thinking and i could be wrong -- but i believe you are thinking as if O- one position on the sphere of a star would be attached to a specific point in space time like the line pointing to the equator of a circle O- and that that position is also attached to the 'fabric' of space time --- well i have noticed that what most people mean by this fabric is gravity density or warpage of space in a particular area. But i choos to think of it in a differnt way --- Yes that point on the star has a specific point in space and time and with both of those coordinates you could go to that exact spot ( if you could travel through time to get there) --- but the fabric is kinda like walking a straight line in a wave pool, you could use the dense gravity ( wave ) to walk faster towards a destination ( walking same direction as the propagation of the wave) or it could steer you off course ( walking perpandicular to the propagation of the wave) , but if it steers you off course you might not notice until you are not being effected by the wave and can rejudge your position

i wonder if that even made sense -- or addressed the question
Alizee
May 06, 2009
This comment has been removed by a moderator.
Alizee
May 06, 2009
This comment has been removed by a moderator.
brant
5 / 5 (1) May 06, 2009
"By contemporary understanding, here's no sharp boundary between neutron stars, quark stars and black holes, which I personally consider as a ultradense neutrino stars, rather then true singularities."

I would however, say that there is a sharp line between fantasy objects and real matter.
Alizee
May 06, 2009
This comment has been removed by a moderator.
Shootist
5 / 5 (1) May 06, 2009
This to me is further proof that space-time does not form a fabric as is popularly described and theorized. Because how could such dense and fast spinning objects not separate / rip from the region of space around them?


It does. The phenomenon is called frame dragging. Even the rotation of the Earth, drags space-time along with it.

As with much else, frame dragging falls out of Einstein's math and can be tested and measured. And has been.

"In addition to black holes, some contemporary scientists are believing in preon stars, quark stars, dark energy stars, fuzzballs, quarkonium stars, gravastars, white holes and many other objects."

Yes. And a Boojun is a particularly viscous type of Snark.
MattLoPilato
2 / 5 (4) May 06, 2009
NEEEEERRRRDS!!!!!!
Mercury_01
not rated yet May 07, 2009
shootist, I want to learn more about frame dragging, because I think I might have an intuitive understanding of it. do you have any good links?
lomed
5 / 5 (1) May 07, 2009
"a teaspoonful of neutron star matter would weigh about 100 million tons."

i take it this is the weight of the matter on the star and not on earth ?

what i mean to say is, its strength is due to the extreme gravity and not because its a special kind of matter or anything ?

sorry if i sound stupid but i dont know much about physics..

I think that is the weight of the matter on Earth. The matter in a neutron star is almost entirely neutrons. This "neutron matter" has a density similar to that of an atomic nucleus. So, in short, it is a special kind of matter and the large number given is due to this matter's extremely high density.
Mercury_01
1 / 5 (2) May 07, 2009
If its so strong, why dont they make bike frames out of it? or it that what is meant by "frame dragging?
Alexa
2.6 / 5 (5) May 07, 2009
..what is meant by "frame dragging..
It's basically a consequence of omnidirectional universe expansion in connection to limited speed of light. For example, Earth rotates and ligh speed cannot follow this motion completelly. This leads to shear-like motion of space-time around Earth.

If you introduce an omnidirectional space-time expansion, it changes the shear motion a bit with distance and you'll get the dark matter phenomena - that's all that simple.
physpuppy
not rated yet May 07, 2009
Since the subject came up about "frame dragging", I thought the following somewhat related article from space.com would be of interest (surprisingly not yet picked up by physorg...):

http://www.space....ive.html

"Star Trek's Warp Drive: Not Impossible"

Alexa
3 / 5 (4) May 07, 2009
As an example of warp drive can serve Woodward effect, EMdrive gadget, Heim's drive and many other constructions. With compare to silly LHC research, these constructions are ignored by mainstream science.

http://en.wikiped.../EmDrive
http://en.wikiped...d_effect
rkolter
not rated yet May 08, 2009
A teaspoon of neutron star material might weigh 100 million tons on Earth, but it'd decay pretty quickly - as someone else mentioned, outside the gravitational well of a neutron star, unbound neutrons have a half-life of about 10 minutes. In about six hours, you'd be down to three pounds of the stuff.



I suspect that it'd be pretty warm in the general vicinity of your teaspoon of neutron star material too - you'd need a teaspoon with a very, very, very high melting point. ;)
El_Nose
not rated yet May 08, 2009
-- QUESTION -- while a nuetron star has the consistantcy of basically Nuetrons and protons lumped together not forming atoms they are so close -- is it possible for a star so dense that nuetrons and protons breaking apart and result in just being a quark soup ?? i think i have my new scifi book theme, the core of a blackhole is a star made of quarks where the strong and weak nuclear forces are over come in a fantasic reaction to breed a new type of star that radiates dark energy into the universe and is of course threatening earth's survival :-)

but seriously could someone answer the question?
jselin
not rated yet May 08, 2009
A teaspoon of neutron star material might weigh 100 million tons on Earth, but it'd decay pretty quickly - as someone else mentioned, outside the gravitational well of a neutron star, unbound neutrons have a half-life of about 10 minutes.


Wouldn't it be busy expanding into something the size of a mountain? ;P
Alizee
May 10, 2009
This comment has been removed by a moderator.
lomed
not rated yet May 23, 2009
-- QUESTION -- while a nuetron star has the consistantcy of basically Nuetrons and protons lumped together not forming atoms they are so close -- is it possible for a star so dense that nuetrons and protons breaking apart and result in just being a quark soup ?? i think i have my new scifi book theme, the core of a blackhole is a star made of quarks where the strong and weak nuclear forces are over come in a fantasic reaction to breed a new type of star that radiates dark energy into the universe and is of course threatening earth's survival :-)

but seriously could someone answer the question?

If I remember correctly, there was a report within the past several months that indicated a star with a very high mass (~1.6 solar masses?) had been discovered. There was speculation that this might be a "quark star." However, as far as I know, the equation of state of matter is not known very well for such high densities (temperatures and pressures.) So, while a sufficiently massive stellar remnant will collapse into a black hole, and a somewhat less massive one (.8?<

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