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solar mass

The sun has a mass of 1.989·10³⁰ kilograms [see exponential notation] what is equal to 332 946 earth masses.

In astronomy, the solar mass is frequently used as a unit of mass (“Neutron stars typically have a mass of 1.4 solar masses”), sometimes written as M_⊙.

Definitioner

Neutron

Elektrisch neutrales, vergleichsweise massives Teilchen; die Kerne der Atome bestehen aus Neutronen und Protonen.

Neutronen sind keine Elementarteilchen, sondern bestehen ihrerseits aus Quarks, die von der starken Kernkraft zusammengehalten werden. Neutronen, Protonen und eine Reihe ähnlicher Teilchen werden zusammengefasst als Baryonen bezeichnet.

Verschiedene Arten von Neutronenmaterie sind der Stoff, aus dem Neutronensterne sind.

sun

The central (and most massive) body of our solar system; the star closest to us; a ball of gas with a radius of ca. 700000 km (for comparison the radius of the earth: 12756 km) and a mass of 1.989·10³⁰ kilograms [see exponential notation]. In the interior of the sun, nuclear fusion processes run their course; they are responsible for the sun's impressive brightness.

stars (star)

A cosmic gas ball that is massive enough for pressure and temperatur in its core to reach values where self-sustained nuclear fusion reactions set in. The energy set free in these reactions makes stars into very bright sources of light and other forms of electromagnetic radiation. Once the nuclear fuel is exhausted, the star becomes a white dwarf, a neutron star or a black hole.

solar mass

The sun has a mass of 1.989·10³⁰ kilograms [see exponential notation] what is equal to 332 946 earth masses. In astronomy, the solar mass is frequently used as a unit of mass ("Neutron stars typically have a mass of 1.4 solar masses"), sometimes written as M_⊙.

mass

In classical physics, mass plays a triple role. First of all, it is a measure for how easy it is to influence the motion of a body. Imagine that you're drifting in emtpy space. Drifting by are an elephant and a mouse, and you give each of them a push of equal strength. The fact that the mouse abruptly changes its path, while the elephant's course is as good as unaltered, is a sure sign that the mass (or, in the language of physics, the inertia or inertial mass) of the elephant is much greater than that of the mouse. Secondly, mass is a measure of how many atoms there are in a body, and of what type they are. All atoms of one and the same type have the same mass, and adding up all those tiny component masses, the total mass of the body results. Thirdly, in Newton's theory of gravity, mass determines how strongly a body attracts other bodies via the gravitational force, and how strongly these bodies attract it (in this sense, mass is the charge associated with the gravitational force). In special relativity, one can also define a mass that is a measure for a bodies resistance to changing its motion. However, the value of this relativistic mass depends on the relative motion of the body and the observer. The relativistic mass is the "m" in Einstein's famous E=mc² (cf. equivalence of mass and energy). The relativistic mass has a minimum for an observer that is at rest relative to the body in question. This value is the so-called rest mass of the body, and when particle physicists talk of mass, this is usually what they mean. Just as in classical physics, the rest mass is a kind of measure for how much matter the body is made up of - with one caveat: For composite bodies, the energies associated with the forces holding the body together contribute to the total mass, as well (another consequence of the equivalence of mass and energy). In general relativity, mass still plays a role as a source of gravity; however, it has been joined by physical quantities such as energy, momentum and pressure.

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solar mass

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