Neutronium

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0 antihydrogen ← neutronium → hydrogen — ↑ Nt [not official] ↓ He periodic table - extended periodic table
General
Name, Symbol, Number	neutronium, Nt [not official], 0
Element category	none
Standard atomic weight	[4][1] g·mol−1
Electron configuration	none
Electrons per shell	0
Physical properties
Phase	unknown
Miscellaneous
Most-stable isotopes
Main article: Isotopes of neutronium iso NA half-life DM DE (MeV) DP 1Nt  ? 14.7617 min β− unknown 1H 2Nt  ? transitory β− unknown 2H 4Nt  ? 4Nt is stable with 4 neutrons
References

Neutronium is a hypothetical extremely dense phase of matter. The term was originally used in science fiction and in popular literature to refer to a highly dense phase of matter composed primarily of neutrons. The word was coined by scientist Andreas von Antropoff in 1926 (i.e. before the discovery of the neutron itself) for the conjectured 'element of atomic number zero' that he placed at the head of the periodic table.^[2][3] However, the meaning of the term has changed over time, and from the last half of the 20th century onward it has been used legitimately to refer to extremely dense phases of matter resembling the neutron-degenerate matter postulated to exist in the cores of neutron stars.

Contents 1 Neutronium and neutron stars 2 Neutronium and the periodic table 3 Neutronium in fiction 4 See also 5 References 6 Bibliography

[edit] Neutronium and neutron stars

The term neutronium is used in popular literature to refer to the material present in the cores of neutron stars (stars which are too massive to be supported by electron degeneracy pressure and which collapse into a denser phase of matter). This term is very rarely used in scientific literature, for two reasons:

• There is no universally agreed-upon definition for the term "neutronium".
• There is considerable uncertainty over the composition of the material in the cores of neutron stars (it could be neutron-degenerate matter, strange matter, quark matter, or a variant or combination of the above).

When neutron star core material is presumed to consist mostly of free neutrons, it is typically referred to as neutron-degenerate matter in scientific literature.

[edit] Neutronium and the periodic table

The term neutronium was coined in 1926 by Professor Andreas von Antropoff for a conjectured form of matter made up of neutrons with no protons, which he placed as the chemical element of atomic number zero at the head of his new version of the periodic table. It was subsequently placed as a noble gas in the middle of several spiral representations of the periodic system for classifying the chemical elements, such as the Chemical Galaxy (2005).

Although the term is not used in the scientific literature either for a condensed form of matter, or as an element, there have been reports that, besides the free neutron, there may exist two bound forms of neutrons without protons. However, these reports have not been further substantiated. Further information can be found in the following articles:

• Mononeutron: Isolated neutrons undergo beta decay with a half-life of approximately 15 minutes, becoming protons (the nucleus of hydrogen), electrons and antineutrinos.
• Dineutron: The dineutron, containing two neutrons, is not a bound particle, but has been proposed as an extremely short-lived state produced by nuclear reactions involving tritium.
• Tetraneutron: A tetraneutron is a hypothetical particle consisting of four bound neutrons. Reports of its existence have not been replicated. If confirmed, it would require revision of current nuclear models.

A trineutron state consisting of three bound neutrons has not been detected, and is not expected to be stable even for a short time. Calculations indicate that the hypothetical pentaneutron state, consisting of a cluster of five neutrons, would not be bound.

And so on, through the numbers, up to icosaneutron, with 20 neutrons.^[4]

If one accepts neutronium to be an element, the above mentioned neutron clusters would be the isotopes of that element.

[edit] Neutronium in fiction

The term neutronium has been popular in science fiction since at least the middle of the 20th century. It typically refers to an extremely dense, incredibly strong form of matter. While presumably inspired by the concept of neutron-degenerate matter in the cores of neutron stars, the material used in fiction bears at most only a superficial resemblance, usually depicted as an extremely strong solid under Earth-like conditions, or possessing exotic properties such as the ability to manipulate time and space. In contrast, all proposed forms of neutron star core material are fluids and are extremely unstable at pressures lower than that found in stellar cores.

Noteworthy appearances of neutronium in fiction include the following:

• In Hal Clement's short story Proof (1942), neutronium is the only form of solid matter known to Solarians, the inhabitants of the Sun's interior.
• In Vladimir Savchenko's Black Stars (1960), neutronium is mechanically and thermally indestructible substance. It is also used to make antimatter, which leads to a fusion explosion accident.
• In Doctor Who (1963), neutronium is a substance which can shield spaces from time-shear when used as shielding in time-vessels.
• In Larry Niven's Known Space fictional universe (1964), neutronium is actual neutron star core material. Niven does not make assumptions about its strength, but imagines that small blobs of it would remain stable (and inevitably spherical) under their own gravity.
• In the Star Trek universe, neutronium is an extremely hard and durable substance, often used as armor, which conventional weapons cannot penetrate or even dent.
• In the computer games Master of Orion (1993), Master of Orion 2 (1996), and Sid Meier's Alpha Centauri (1999), neutronium is the second strongest armor type that can be researched in MoO1 and MoO2, and the third strongest in SMAC. MoO1 and MoO2 also feature "neutronium bombs", which are extremely powerful planetary bombardment weapons which causes damage due to gravitic effects.
• In Peter F. Hamilton's novel The Neutronium Alchemist (1997), neutronium is created by the "aggressive" setting of a superweapon.
• In Stargate SG-1 (1997), neutronium is a substance which is the basis of the technology of the advanced Asgard race, as well as a primary component of human-form Replicators.
• In Bioware's game Mass Effect - Element Zero (a variation on Neutonium) or 'eezo' is used for generating the "mass effect" by applying electrical current to the substance. Positive current causes apparent mass to increase, and negative current causes apparent mass to decrease (this can even create negative mass allowing for anti-gravity and Faster-than-light travel). It is typically found in asteroids debris orbiting neutron stars and pulsars.

[edit] See also

• Neutron star
• Degenerate matter
  • Neutron-degenerate matter
• Compact star

[edit] References

[edit] Bibliography