Densest Object on Earth Made From Compressed Copper

Lawrence Livermore’s National Lab’s National Ignition Facility compressed microscopic copper samples with pressures of 30 million atmospheres to triple the density of copper. This created the densest object on the planet for a brief moment in time.

They used diamond turning machines to make microscopic copper stairs whose surface roughness surpassed optical qualities and precision metrology to measure sample thickness to 1 billionth of a meter. They tracked the copper sample traveling at 50,000 miles per hour using a velocity interferometer — the world’s most sophisticated radar gun.

Measuring the compression was one of the greatest challenges.

They took a series of X-ray images to monitor the crystalline structure as the copper compressed. They also measured how the speed of sound waves changed as the copper was squeezed.

Physical Review Letters – Probing the Solid Phase of Noble Metal Copper at Terapascal Conditions

Ramp compression along a low-temperature adiabat offers a unique avenue to explore the physical properties of materials at the highest densities of their solid form, a region inaccessible by single shock compression. Using the National Ignition Facility and OMEGA laser facilities, copper samples were ramp compressed to peak pressures of 2.30 TPa and densities of nearly 30 grams per cc, providing fundamental information regarding the compressibility and phase of copper at pressures more than 5 times greater than previously explored. Through x-ray diffraction measurements, we find that the ambient face-centered-cubic structure is preserved up to 1.15 TPa. The ramp compression equation-of-state measurements shows that there are no discontinuities in sound velocities up to 2.30 TPa, suggesting this phase is likely stable up to the peak pressures measured, as predicted by first-principal calculations. The high precision of these quasiabsolute measurements enables us to provide essential benchmarks for advanced computational studies on the behavior of dense monoatomic materials under extreme conditions that constitute a stringent test for solid-state quantum theory. We find that both density-functional theory and the stabilized jellium model, which assumes that the ionic structure can be replaced by an ionic charge distribution by constant positive-charge background, reproduces our data well. Further, our data could serve to establish new international secondary scales of pressure in the terapascal range that is becoming experimentally accessible with advanced static and dynamic compression techniques.

32 thoughts on “Densest Object on Earth Made From Compressed Copper”

  1. “Oh, you know that because it is no longer classified?”

    This is fairly well established from multiple lines of evidence that are internally consistent.

    There are official statements and descriptions.

    There are leaked spy documents.

    There is a lot of information in the various descriptions of the Louis Slotin criticality accident that involve a large number of credible people and scientists at various institutions.

    There’s the plausibility of the claim itself. A solid pit without levitation is the most expedient and easy to get working with much less instability and timing problems than a hollow or levitated pit. Mixing of an high energy alpha emitter and beryllium does yield neutrons. The rate of neutrons expected for amounts of material of isotopes known to be produced at the time are in the correct order of magnitude to produce enough neutrons on the relevant time scales.

    It is consistent with information from other nations weapon’s programmes.

    You’re quickly getting into the territory of requiring the soviet union, france, britain and the US to co-conspire and the unruly bunch that is scientists at the national labs to make claims that are intentionally misleading over a span of 5 decades.

  2. “You been there, eh?”

    This is as well understood and in the same ways as most other things which we cannot directly touch and feel.

    We can see what S and P waves do at the inner and outer core.

    We can look at the magnetic field.

    We can put things in diamond anvils and see what they do at moderately high pressures.

    We can collapse things with powerful lasers; and we have been for 30 years both for nuclear fission bomb research (a big part of NIF was more detailed measurements of the equation of state of plutonium, uranium etc at the pressures exceeding those available by conventional explosives, as happens in the “spark plug” of the secondary), nuclear fusion research and astronomy and earth science research (knowing how matter behaves at extremes of pressure and temperature allow models for astronomical objects to be calibrated).

    We can look at the stuff left orbiting the sun from before the formation of the earth.

    The earth’s core is 3% less dense than pure iron at the known pressure and estimated temperature. This leaves room for a few percent lighter elements like sulfur, silicon etc. and room for up to 10% nickel.

    It leaves no room for large amounts of uranium, or gold or anything like that. Most of the heavy elements are directly excluded by their low abundance in the solar system.

    We’re about as sure that the Earth’s inner core is quite pure and solid iron as we are that the sun is about 75% hydrogen and 25% helium.

  3. “Iron in Earth’s core is ~1.6 times as dense as iron at STP.”

    You been there, eh? You know it, huh? You sure it’s iron? Why wouldn’t it be 50% Uranium and whatever mix?

    “The first implosion-type nuclear weapons used a solid pit (just a small neutron generating device in the center) with a tamper/pusher to simply compress the pit by high pressure and phase transition.”

    Oh, you know that because it is no longer classified?

    I agree that all Google-available info regarding Fat Man shows a mostly solid pit except for the center where urchin was placed…

    I maintain my assertion that HEX cannot be used to attain “center of the earth” pressures that would take plutonium to 30g/cc. What I do know is that the delta to alpha allotrope phase change is such a real thing that they needed to alloy the Pu with Gallium to keep it from spontaneously tansforming… but then again, that is just google-available accounts of something that happened 80 years ago.

    They eventually got 40 kT out of that basic design using an air gap between the HEX and the whatever pusher/tamper component allowing some kind of slapping effect that didn’t occur with a solid stack of components… again google-available information of questionable pedigree.

    Just calling out that you can’t believe you are an expert in nuclear weapons just because you’ve read everything you could find on the internet. There is undoubtedly a lot of conjecture and MISINFORMATION out there, some intentional misdirection…

  4. Iron in Earth’s core is ~1.6 times as dense as iron at STP. If the iron was also cool it should be slightly denser still.

    Assuming this is still true of plutonium (and it probably is, since depleted uranium and other metals have been used as stand-ins in implosion tests and hydrodynamic tests), then ~1.6 times density is a much larger effect than the 1.25 times denser alpha phase of plutonium. Toghether they should multiply up to about a factor 2 density increase.

    The first implosion-type nuclear weapons used a solid pit (just a small neutron generating device in the center) with a tamper/pusher to simply compress the pit by high pressure and phase transition. Critical mass has since been lowered greatly and this is not on the part of better neutron reflectors but hollow and/or levitated pits that reach higher density.

  5. I would have thought that osmium would be even more dense if given this treatment–sphere packing and all

  6. Metals are certainly not compressible enough to ‘double or triple’ the 20g/cc of plutonium with high explosives… This article claims that 30 Mbar takes copper from 9 g/cc to 30 g/cc using the penultimate most expensive piece of lab equipment on Earth – the NIF.

    Thanks for googling the pressures obtainable with high explosives.

  7. A quick search revealed that explosives can directly reach 400 Kbar, which is 5,800kpsi. And by converging the shock waves, you can reach several megabars, roughly equal to the pressure at the center of the Earth, not merely at the bottom of the ocean.

    At those kinds of pressures, no, you can no longer treat solid metal as incompressible.

  8. Simple google:
    Sun core density: 150 g/cc
    Copper normal density: 9 g/cc x 3 = 27 g/cc (abstract says “nearly 30 g/cc”)

    Black hole density depends on its mass. The higher the mass, the less density is needed to form a black hole. The schwarzschild radius is proportional to mass, but volume is proportional to the cube of the radius, so the density of a black hole is inversely proportional to the square of the mass:

    d = M/V ~ M/r^3 ~ M/M^3 = 1/M^2

  9. Leif Holmlid – Google Scholar Citations

    His record of journal publication extends back to the middle 1970’s. He has a profound interest in Rydberg matter—decades of data accumulated in experiments. The hydrogen discovery was a serendipitous find in resolving a data anomaly within an experiment utilizing time-of-flight mass spectrometry measurements.

  10. As I understand, this experiment doesn’t involve static pressure. The forces are very short-lived and quickly change over time, so it’s dynamic compression. Matter reacts differently to static and dynamic forces. Static means it has enough time to relax into an equilibrium state. Dynamic means it doesn’t have enough time.

    However, I don’t know what critical threshold you’re referring to, so can’t say if it still applies in a dynamic compression situation.

  11. J. B. over at Vortex-L has read this NBF article/comments. He proposes that ultra dense deuterium likely reigns as the most dense material manufactured by humanity. Life Homilid asserts that this material is >130kg per cubic cm and likely metastable. Lab samples in a properly isolated environment persisted for many weeks duration.

    The Vortex question—what happens if one combines fertile materials with UDD to form a hydride, then subjects it to shock compression? Homilid’s research publications present the evidence for a previously undocumented nuclear reaction, one which even generates mesons from the pure protium variant material when properly stimulated.

  12. Interesting to note that the critical threshold of 1565 gigapascals static pressure seems to have been exceeded without reversing subatomic particles constituting the material.

  13. This created the densest object on the planet for a brief moment in time.

    If my wife had made the above statement , I’d be forced to concede that, yes, at the time this was the densest material on the (surface) of the Earth, assuming no nukes were being set off at the same moment.

    But anyone who doesn’t sleep with me, they got it wrong.

  14. If one applies three million atmosphere pressure in order to crush a 6 kg plutonium sphere to the size of a golf ball by detonating a shell of explosives, wouldn’t that count as the first and most dense material produced? Unfortunately, no do-overs if one blinked at the wrong moment!

  15. So when plutonium core is compressed at 2~3 normal density (19.86) in any nuclear device primary over the last fifty years, that was not the densest, but copper (8.92) is.
    OK, professor.

  16. Well, possibly, but IIRC, Copper IS used in shaped charges, so might also be a legitimate subject of modeling on it’s own.

  17. NIF wasn’t meant for fusion, it was built to recreate conditions in thermonuclear devices so that we could test and validate weapon models and honor the nuclear test ban treaty.

    Any other use is “marketing”.

  18. I suppose this extreme case works to validate the models for how Pu behaves when suddenly compressed.

    What? Oh, did I say Pu? Silly me, totes meant Cu.

  19. Just love it!

    Those inscrutable Physicists!
    Building multi-billion dollar power-of-the-Sun lasers.
    Pointing them at a ‘bit’ of gold with a hole in the center.
    In which they suspend a wee bit of copper.
    And illuminate it with a power X-ray laser beam.
    Not to vaporize it, but for metrology.

    And then hit the thing with all the power they got.

    Just wow.

    Thing is, pure science is always this way.
    Full of things that are so far removed from practical…
    That it makes ordinary brains explode.
    Poor pun.

    Just short of arranging a thermonuclear explosion 
    To do the compression, its pretty decent science!

    Now back to our regular programming.
    Whether the British Crown will accept her Wandering Goat kids.

    ⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  20. I think it’s a bit of a stretch to call something in the process of coming apart an “object”. Doesn’t that usually imply at least some degree of stability?

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