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Comet Shoemaker-Levy 9
Comet Shoemaker-Levy 9 (SL9, formally designated D/1993 F2) was a comet which collided with Jupiter in 1994, providing the first direct observation of the collision of two solar system ... > more -
Black body
In physics, a black body is an object that absorbs all electromagnetic radiation that falls onto it. No radiation passes through it and none is reflected, yet in classical physics, it can ... > more -
Precession of the equinoxes
The precession of the equinoxes refers to the precession of Earth's axis of rotation with respect to inertial space. The precession of the equinoxes is caused by the differential gravitational forces ... > more -
Comet Hale-Bopp
Comet Hale-Bopp was probably the most widely observed comet of the 20th century, and one of the brightest seen for many decades. It was visible to the naked eye for a record 18 months, twice as long ... > more -
Black hole
A black hole is a concentration of mass great enough that the force of gravity prevents anything from escaping it except through quantum tunnelling behaviour (known as Hawking Radiation). The ... > more -
Planetary nebula
A planetary nebula is an astronomical object consisting of a glowing shell of gas and plasma formed by certain types of stars at the end of their lives. They are in fact unrelated to planets; the ... > more -
Electromagnetic spectrum
The electromagnetic spectrum is the range of all possible electromagnetic radiation. Above infrared in frequency comes visible light. This is the range in which the sun and stars similar to it emit ... > more -
Definition of planet
The definition of "planet" has for some time been the subject of intense debate. Although the word dates back thousands of years, no officially decreed scientific definition of "planet" existed ... > more -
Precession
Precession refers to a change in the direction of the axis of a rotating object. In certain contexts, "precession" may refer to the precession that the Earth experiences, the effects of this type of ... > more -
Stellar classification
In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral ... > more
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