Glossary -- B

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Glossary links (select a letter for definitions of astronomy terms beginning with that letter):
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Big Bang
a theory of the creation of the universe from an ultra-compact volume with very high temperatures about 13.7 billion years ago. The ultra-compact volume began expanding and is responsible for the expanding motion we see today.
bio-marker
spectral signatures of certain compounds in certain proportions that could not be produced by non-biological processes. Also called "biosignature".
black hole
the collapsed core for the most massive stars. Formed from the total collapse of a core greater than 3 solar masses to an infinitesimal point of infinite density. Gravity in the region surrounding the collapsed core is so strong that the escape velocity is greater than the speed of light. Far beyond that region, black holes obey Newton's law of gravity.
blueshift
the shift of spectral lines from an object to shorter wavelengths because the object is moving toward the observer. The greater the speed of the object, the greater the blueshift will be.
brown dwarf
object formed from the gravitational collapse of a gas cloud just as a star is but having too little mass (less than 0.08 solar masses) to undergo nuclear fusion reactions.

Glossary links (select a letter for definitions of astronomy terms beginning with that letter):
A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z

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last updated: May 20, 2019

Is this page a copy of Strobel's Astronomy Notes?

Author of original content: Nick Strobel