Transcript AstronomyGlossaryx

Astronomy
Glossary of Key Terms
"I don't think the human race will survive the next thousand years unless we spread into space." —
Stephen Hawking
“It’s been exactly one whole year since I saw you last, 12 Months!”
“I know! Scientifically speaking, the Earth has only made one revolution around the sun, the
moon has orbited the earth about 12 times since I saw you last! And the Earth has rotated
on it’s axis 365 and ¼ times! How have you been?”
We don’t normally speak scientifically!
A glossary of key terms will help you to develop your ‘Science Vocab’ to enable you to develop
your Science Knowledge and understanding… mostly just so you know what we are talking about.
Scientific Vocabulary
This refers to the words used by scientists to accurately describe matter,
organisms, processes and systems. These words have an exact meaning or
definition, and application. Sometimes these words are used incorrectly or
imprecisely when applied in everyday use.
Because Science is dynamic -characterized by constant change, activity, or progress,
you may find that sometimes the definitions for science vocabulary will change and
develop as scientists continue to understand the universe by incorporating new ideas,
thinking and experimental evidence.
It’s important to have the correct most up to date definitions of science vocabulary.
Milky Way Galaxy (northern band) many bright stars, dark dust lanes, red emission nebulae, blue reflection nebulae and
star clusters can be seen. Astronomy Picture of the Day, John P. Gleeson July 10, 2011
http://apod.nasa.gov/apod/archivepix.html
Astronomy
The branch of science that deals with celestial objects, space, and the
physical universe as a whole.
Astronomy was greatly furthered by the invention of the telescope.
From the Greek word astronomos meaning ‘star-arranging.’
Celestial
Positioned in or relating to the sky, or outer space as observed in
astronomy: a celestial body.
Astrology
The study of the movements and relative positions of celestial bodies
interpreted as having an influence on human affairs and the natural world.
Ancient observers of the heavens developed elaborate systems of explanation based
on the movements of the sun, moon, and planets through the constellations of the
zodiac, for predicting events and for casting horoscopes. By 1700 astrology had lost
intellectual credibility in the West, but continued to have popular appeal. Modern
astrology is based on that of the Greeks.
Constellation
a group of stars forming a recognizable pattern that is traditionally named after its
apparent form or identified with a mythological figure. Modern astronomers divide
the sky into eighty-eight constellations with defined boundaries
Zodiac
a belt or ring of constellations that lines the ecliptic (the apparent path of the sun,
the path of the moon and planets roughly lie within the ecliptic also) It is divided
into twelve equal signs (Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra,
Scorpio, Sagittarius, Capricorn, Aquarius, Pisces).
Horoscope
forecast of a person's future, typically including a delineation of character and
circumstances, based on the relative positions of the stars and planets at the
time of that person's birth.
• a short forecast for people born under a particular sign, esp. as published in a
newspaper or magazine.
Astronomer
An expert in or a student of astronomy.
Gravity
The force that attracts a body toward the center of the earth, or toward any
other physical body having mass.
Mass
The quantity of matter that a body contains.
Mass and weight are not the same. In science these words have special
meanings. Mass is a measure of the amount of matter (material) in an object and
is commonly measured in grams (g) or kilograms (kg).
Weight
The force acting on the mass of a body by a gravitational field.
Weight and mass are not the same. Weight is a measure of the force of gravity pulling
on a mass and is measured in newtons (N). Under ordinary conditions the mass of an
object can be said to be constant (the object’s mass will be the same at different
locations in the Universe). The weight of an object is not constant, since the force of
gravity varies from place to place
Day
A single rotation of a planet
Year
The time taken by a planet to make one revolution around the sun.
Lunar Month
A month measured between successive new moons (roughly 291/2 days).
The earth’s moon orbits the earth in a period of 29.5 days. There are different
phases of the moon illuminated during its orbit. .
Phases of the moon
Lunar phase is the appearance of the
illuminated (lighted) portion of the
Moon as seen by an observer, usually
on Earth.
• The lunar phases changes as the Moon
orbits the Earth, according to the positions
of the Earth, Moon, and Sun.
•One half of the lunar surface is always
illuminated by the Sun (except during lunar
eclipses), and is bright, but…
• the portion that is visible to an observer
can vary from 100% (full moon) to 0%
(new moon).
Eclipse
An obscuring of the light from one celestial body by the passage of another
between it and the observer or between it and its source of illumination.
E.g. Lunar eclipse: an eclipse in which the moon appears darkened as it passes into
the earth's shadow.
E.g. Solar eclipse: an eclipse in which the sun is obscured by the moon.
Lunar Eclipse time lapse video (39sec)
http://www.youtube.com/watch?v=Xuej7_orvfM&feature=related
Moon
The natural satellite of the earth, visible (chiefly at night) by reflected light
from the sun. A natural satellite of any planet.
The earth's moon orbits the earth in a period of 29.5 days, going through a series
of phases from new moon to full moon. A natural satellite or moon is a celestial
body that orbits a planet or smaller body, which is called its primary.
Artificial Satellites
An artificial body placed in orbit around the earth or moon or another
planet in order to collect information or for communication.
Planet
The definition of planet set in 2006 by the International Astronomical Union
(IAU) states that in the Solar System a planet is a celestial body that: is in orbit
around the Sun,
has sufficient mass to assume hydrostatic equilibrium (a nearly round shape),
and has "cleared the neighbourhood" around its orbit.
Sun
The star around which the earth orbits. The sun is the central body of the solar
system. It provides the light and energy that sustains life on earth, and its position
relative to the earth's axis determines the terrestrial seasons.
Solar System
The collection of eight planets and their moons in orbit around the sun,
together with smaller bodies in the form of 5 dwarf planets, small solar
system bodies (SSSB), asteroids, meteoroids, and comets.
Galaxy
A system of millions or billions of stars, and stellar remnants, an
interstellar medium (between stars) of gas and dust and an important but
poorly understood component tentatively dubbed dark matter, held
together by gravitational attraction. The Milky way is the galaxy of which the
solar system is a part; is located is a disk-shaped spiral galaxy with
approximately 100,000 million stars.
Universe
All existing matter and space considered as a whole; the cosmos.
The universe is believed to be at least 10 billion light years in diameter and
contains a vast number of galaxies; it has been expanding since its creation in
the big bang about 13 billion years ago.
Telescope
An instrument designed to make distant objects appear nearer, containing
an arrangement of lenses, or of curved mirrors and lenses, by which rays
of light (electromagnetic radiation) are collected and focused and the
resulting image magnified.
Space Probe
An unmanned exploratory spacecraft designed to transmit information
about its environment.
253 Mathilde
The 253rd asteroid to be
discovered, measuring about
50km across.
Photo taken 1997 by NEAR
Shoemaker probe.
Asteroid
A small rocky body (SSSB) orbiting the sun.
Large numbers of these, ranging in size from nearly 1,000 km across to dust
particles, are found esp. between the orbits of Mars and Jupiter and a few pass
close to the earth or enter the atmosphere as meteors.
Comet-Hale-Bopp-29-031997
Comet
A celestial object consisting of a nucleus of ice and dust and, when near the sun,
a “tail” of gas and dust particles pointing away from the sun.
Meteor
A small body of matter from outer space that enters the earth's
atmosphere, becoming incandescent -emitting light as a result of being
heated as a result of friction and appearing as a streak of light.
Black Hole
A region of space having a gravitational field so intense that no matter or
radiation can escape. Probably formed when a massive star exhausts its
nuclear fuel and collapses under its own gravity.