General astronomy

General astronomy

Contributors in General astronomy

General astronomy

(RA): position on the celestial sphere measured with respect to the vernal equinox position on the celestial equator. It is a projection of longitude lines onto the sky and converted to time units. ...

rotation curve

Astronomy; General astronomy

how the orbital velocities of objects in the disk of a spiral galaxy vary with increasing distance from the center of the galaxy. The rotation curve is used to study the distribution of mass in a ...

RR Lyrae

Astronomy; General astronomy

(variable star): a type of low-mass variable stars that all have the same average luminosity. RR Lyrae are valuable for determining distances to star clusters.

runaway greenhouse

Astronomy; General astronomy

a process in which the heating of a planet increases the greenhouse effect in a feedback loop resulting in a dramatic change in the atmospheric composition and dramatic rise in the surface ...

runaway refrigerator

Astronomy; General astronomy

a process in which the cooling of a planet's surface decreases the greenhouse effect in a feedback loop resulting in a dramatic change in the atmospheric composition and dramatic cooling in the ...

Schwarzschild radius

Astronomy; General astronomy

the distance from a black hole's center at which the escape velocity equals the speed of light (same as the event horizon).

seeing

Astronomy; General astronomy

a measure of the amount of turbulence of the air. When the seeing is ``good'', the amount of turbulence is small and the images are steady (little twinkling). ``Poor'' seeing occurs when the ...