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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
- latitude
- used to specify position on the Earth, it is the number of
degrees north or south of the Earth's equator.
- law of gravity
- (Newton's): the force of mutual attraction between two
objects =
G×(mass #1) × (mass #2) / (distance between the
objects)2. The term G is a universal constant of nature that
always = 6.672× 10-11 meter3/(kilogram second2).
- life zone
- the region around a star where the
temperature on a planet's surface is
between the freezing point (0° C) and boiling point (100° C) of water.
- light curve
- a plot of how an object's brightness changes over time.
- light-gathering power
- the ability of a telescope to collect more light
than the human eye in a given amount of time. It depends on the
area of the
telescope's objective, such that the larger the collecting area of the objective,
the brighter the image will be.
- lighthouse model
- a model describing how pulsars pulsate:
the rapidly rotating neutron star produces a narrow beam of light
from its magnetic field and if the magnetic pole is aligned with the
Earth, the narrow beam of light sweeps over us periodically like the
beam of a lighthouse does for ships at sea.
- light year
- distance light travels in one year (9.461 trillion kilometers,
over 63,000 A.U.!). Used for
interstellar distances.
- line of nodes
- the intersection of a planet's or the
Moon's orbit with the Earth's orbit.
- lithosphere
- the layer of hard rock that includes the crust and the outermost part of the mantle in a terrestrial planet.
- local noon
- when the Sun is on an observer's meridian.
- long period comet
- a comet with an orbit period of thousands
to millions of years long that comes from the Oort cloud.
- longitude
- used to specify position on the Earth, it is the number of degrees east or west of the
0° line going through Greenwich, England.
- luminosity
- the total amount of energy radiated by an object every second.
- lunar eclipse
- when the shadow of the Earth hits the Moon at
exactly full phase.
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
last updated:
May 28, 2010
Is this page a copy of Strobel's
Astronomy Notes?
Author of original content:
Nick Strobel