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neutral particle
subject			fact

neutral particle	is not accelerated by electric or magnetic fields
	has charge 0
	has definition A particle with zero charge
	is a kind of particle
particle	obeys uncertainty principle
	has frequency inversely proportional to the wavelength
	has wavelength inversely proportional to its momentum
	has mass
physical object	has location or center of gravity
	has angular momentum
	has velocity
	has momentum
	has temperature
	has volume
	has extent
	has material

Kinds of neutral particle :

• ammonia (3 facts) (NH₃)
• antineutrino (5 facts) - The antiparticle of a neutrino.
• antineutron (6 facts) - The antiparticle of a neutron. A neutron and antineutron both have the same mass and zero electric charge, but can be differentiated by their interactions: a neutron and an antineutron can annihilate into gamma rays, while two neutrons cannot.
• carbon monoxide (5 facts) (CO) - A molecule consisting of one carbon atom and one oxygen atom. It is the most abundant interstellar molecule after molecular hydrogen and is especially useful because it radiates at radio wavelengths, so astronomers can use it to map the distribution of molecular hydrogen.
• graviton (12 facts) - A massless spin-2 particle which is the hypothetical quantum of the gravitational field. It mediates the force of gravity in a similar way to that in which the spin-1 gauge bosons (i.e. the photon, W^±, Z⁰, and gluons) mediate the other forces., A hypothetical elementary particle associated with the gravitational interaction. It is a stable particle with zero rest mass, zero charge, and a spin of ± 2, and travels with the speed of light., Smallest bundle of the gravitational force field; messenger particle for the gravitational force., The hypothetical quantum particle of the gravitational field. It could also be thought of as a quantized element of space-time curvature., A quantum of gravitational radiation., The quanta thought to convey gravitational force; analogous to the photons, gluons, and intermediate vector bosons of electromagnetism and the strong and weak nuclear forces. Predicted by quantum theory of gravity, gravitons have not yet been detected.
• methanol (6 facts) (CH₃OH, methyl alcohol) - More rotational lines have been observed astronomically for it than for any other molecule.
• molecular hydrogen (2 kinds, 10 facts) (H₂) - A molecule consisting of two hydrogen atoms (H₂) and the most common molecule in space., A molecule of hydrogen, discovered in interstellar space in 1970. H₂ is a very hard molecule to detect. None of its transitions lie in the visible part of the spectrum. Second, being a symmetric homonuclear molecule, it does not have an electric-dipole rotation-vibration spectrum, and detection must be based on the weak quadrupole spectrum. Third, ultraviolet radiation is a very efficient dissociator of H₂, so any H₂ that survived would presumably be located inside very dense interstellar clouds. So far observations have borne out this supposition. Measurements of the region within about 1 kpc of the Sun suggest that H₂ is about twice as abundant as atomic H.
• molecular oxygen (4 facts) (O₂)
• neutrino (9 facts) - An electrically neutral, very weakly interacting particle, with a rest energy which is either zero or very small. The particle was predicted in 1931 as a means of reconciling the measurements of beta decays with the conservation of energy, but it was not directly detected until 1956., Chargeless species of particle, subject only to the weak force., An electrically neutral, massless particle of spin-1/2, which interacts only by the weak force and gravity. It was first postulated by Pauli in 1930 to ensure conservation of energy and angular momentum in nuclear β decay. Three different types of neutrinos are known to exist corresponding to the three massive leptons: ν_e, ν_µ and ν _τ., A fundamental elementary particle with no electric charge and very small if any rest mass. Believed to be exceedingly abundant in the universe. The neutrino has a very low cross-section for interaction with matter and is almost impossible to detect, hence the uncertainty over its rest mass. The Sun produces neutrinos from thermonuclear reactions in its core, and a large flux of neutrinos carries away most of the energy, of a supernova. Neutrinos are one candidate for Dark Matter. Experiments to detect cosmic neutrinos involve large masses of "stopping" material and indirect detection of the effects of neutrino absorption., A stable particle with no charge, a rest mass of zero, and a spin of 1/2, that carries away energy in the course of nuclear reactions. Its main characteristic is the weakness of its interactions with all other particles. Since the wavelengths of neutrinos at the energies at which they are normally emitted from unstable nuclei are only a few thousandths of an angstrom (compared with the wavelength of a light photon which is several thousand angstroms), they have negligible probability (10^-19 that of a light photon) of interacting with matter and escape at the speed of light. Neutrinos arise only in the energy-producing regions of stars and therefore, unlike light photons, provide direct evidence of conditions in stellar cores. There are two types of neutrinos, those associated with electrons (v_e) and those associated with muons (v_µ).
• neutron (14 facts) - Particle in the nucleus of all atoms except hydrogen. Through beta decay, a neutron may become a proton and an electron; the process occurs in reverse during the formation of a neutron star., One of the constituents of the atomic nucleus discovered in 1932. It is bound into atomic nuclei by the strong nuclear force. Free neutrons decay slowly via the weak nuclear force. Despite being electrically neutral, the neutron possesses both an electric dipole moment (as if it were made of positive and negative charges separated a minute distance) and a magnetic moment, indicating some internal substructure., A neutral baryon., A nuclear particle with a mass slightly greater than that of a proton. A free neutron decays, after a half-life of about 10.6 minutes, into a proton, an electron, and an antineutrino. The neutron is probably made up of still more fundamental particles having both positive and negative charges. The charges balance to give a net charge of zero, but the motions of the charges are such that their magnetic contributions do not cancel and consequently the neutron is magnetic., typically found in the nucleus of an atom., Stable within the nucleus, the neutron if isolated decays, with a ha half-life of fifteen minutes.
• photon (43 kinds, 137 facts) (electromagnetic radiation) - Smallest packet of the electromagnetic force field; messenger particle of the electromagnetic force; smallest bundle of light., The quantum of the electromagnetic field. It is the massless spin-1 gauge boson of QED. Virtual photons mediate the electromagnetic force between charged particles. Virtual photons can also adopt a mass for a short period, in accordance with Heisenberg's uncertainty principle., A transverse wave of electric and magnetic fields which can propagate through empty space.
• pi0 (4 facts)
• positronium (4 facts) - A positron and electron bound together electrostaticaly.
• water vapor (3 facts) (H₂O)

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