astronomy /space science
TRANSCRIPT
Astronomy /Space Science
Astronomy is the field of science that studies the stars,
planets, and other objects in space – how they formed, how
they interact with each other, and what will happen to them
in the future.
A
atmosphere – the gas that surrounds a celestial object, on
Earth it consists mostly of nitrogen and oxygen.
B
binoculars – an instrument with lenses in two short tubes
used to make far away objects appear closer - not as
powerful as a telescope, but with even simple binoculars we
can see craters on the Moon.
C
D
comet – a ball of ice, dust, and gas that travels through
space in a very elongated orbit around the Sun. When a comet
gets close to the Sun, it sprouts tails of gas and dust.
day – length of time it takes for one complete rotation (one spin)
of a planet; on Earth, 24 hours.
E
Earth – the planet that humans live on, the third from the
Sun.
F
full Moon – a phase in the Moon’s monthly cycle where it is
opposite the Sun in the sky and it appears from Earth as a
fully illuminated round object (Moon’s phases: new > waxing
crescent > first quarter > waxing gibbous > full > waning
gibbous > last quarter > waning crescent > new).
G
galaxy – a large group of billions to hundreds of billions of
stars held together by gravity. Within the universe, there are
hundreds of billions of galaxies. The Earth is located in the
Milky Way Galaxy.
H
Hubble Space Telescope – a telescope orbiting 375 miles above
the Earth that takes detailed pictures of objects in the
universe. Many telescopes on the ground are bigger, but unlike
Hubble, their view is blurred by the atmosphere.
I
Interstellar medium – the gas and dust between stars in our
galaxy. Where it is thickest, it blocks our view of more
distant stars.
J
Jupiter – in the same solar system as Earth, it is the fifth
and largest planet from the Sun. Its thick atmosphere includes
the Great Red Spot, a gigantic hurricane-like storm that’s
been raging for hundreds of years. The dark spot indicates
the shadow of one of its moons.
K
Kuiper belt – a disk of icy asteroids and comets that orbit the
Sun from just about Neptune’s orbit to beyond Pluto.
L
Lunar Rover – a dune buggy - like vehicle that helped carry
astronauts around the Moon as they explored for rocks to
bring back to Earth.
M
Moon – a natural satellite that orbits around a planet. Earth
has 1, and Saturn has at least 62.
N
nova – a star that pulls gas from a companion star and then
explodes, suddenly brightening by hundreds of thousands of
times and then fading away within a few weeks.
O
observatory – a collection of buildings equipped with
telescopes, both large and small, used to study the objects in
the universe.
P
planet – any large spherical object that revolves around a
star but doesn’t shine by its own light (instead reflecting the
light of its star). Smaller spherical objects that revolve
around stars are called dwarf planets.
Q
Quadrantids – a meteoroid is a solid body that travels in
space, it becomes a meteor, also called a “shooting star,”
when it enters the earth’s atmosphere and burns up, a meteor
shower occurs when several dozen or hundreds strike at the
same time. The Quadrantids meteor shower strikes the Earth
annually around January 3rd.
R
rotation – the spinning of an object about its axis or center
point. For a planet in our solar system, because of rotation, at
any given time half the planet faces the Sun (the day side)
and the other part faces away from the Sun (the night side).
Minute by minute, part of the Earth comes into the light and
part goes into the dark.
S
star – a huge ball (typically millions of miles across) of hot gas
that generates its own light through nuclear fusion in its
center. Stars take millions of years to form and can burn for
billions of years. Our Milky Way Galaxy contains several
hundred million stars.
T
telescope – an instrument that uses mirrors or lenses in a tube
to collect and focus light from distant objects, such as
planets and galaxies, making them appear closer and larger.
U
Uranus – a planet in our solar system, seventh from the Sun,
and the first to be discovered with a telescope, in 1781 by
William Herschel.
V
Voyager – a NASA mission that launched two identical
spacecraft to the outer planets in 1977, providing close-up
views of Jupiter, Saturn, Uranus, and Neptune and many of
their moons. Voyagers 1 and 2, both still transmitting signals,
are now headed out of the solar system.
W
world – a planet, such as Earth, that does or could support
life. It must have water, a breathable atmosphere, the right
temperature, and so on. Astronomers are searching for other
worlds like ours.
X
X-ray astronomy – the field that studies some of the most
energetic radiation in the universe, such as the glow of hot
gas in the space between galaxies, which is invisible to
ordinary (visible-light) telescopes.
Y
year – the time it takes for a planet to orbit its star. The
Earth takes 365¼ days to circle the Sun, so for us, 1 year is
365¼ days.
Z
zenith – the point in the sky directly overhead (in other
words, straight up).