Current Model of the Universe
The moon
When it is visible, the M______ is the biggest and
The cycle repeats itself every 30 days ( monthly)
b_________ object in the night sky. The moon
does not make its own l_____ but acts like a giant
mirror in the s____, reflecting sunlight down to
you. This is the light you see. Sometimes you will
see the M_______ full face (known as full moon)
with its carters and ‘seas. At other times, you will
only see h______ of it (a quarter m_______ or a
slice of it (a crescent moon). These different views
of the m______ are known as its p________. The S____ lights up half the M______ but we
on E________ do not always see that half: what phase you see depends on how the
M_______, S_____ and E________ are arranged in s______.
Stars
S________ are massive burning balls of
h____________ gas. Hydrogen is explosive
but the l_______ and h_______ that comes
from hot stars is not from normal
h____________explosions. It comes from
n___________ explosions instead! A nuclear
reaction (called a f__________ reaction)
converts h_____________ into helium,
releasing enormous amounts of e_________
as heat, light and r__________________ as it does so.
The nearest star to E________ is the S_____, being ónly’150 million kilometers from us. At
this distance, the l___________and h_________ from those n___________ explosions takes
just over 8 m____________ to reach us.
The other s___________ you see in the night sky are much further a_________. After the
night S______, the next closest s_______ is Proxima Centauri. It is approximately 40 million
million kilometers away and it takes 4.2 years for its l_________to reach us on E_________.
The other s__________ you see are even further away- the light from some of them takes
millions of y__________ to reach us!
The Milky Way
The M_______________ is the galaxy that
contains our Solar S____________, with the
name describing the galaxy's appearance from
E____________. The Milky Way is a large
barred spiral g____________. All the stars we
see in the night s_______are in our own Milky
W_______ Galaxy. A band of light runs across
the night sky from one h______________ to the other. In ancient times, people thought
that this looked like a road made of m________. That’s why it was named the
M________Way. Scientists now know that this white band is the light from more than 200
b______________ stars. Most of these stars are too far away to be seen distinctly or
individually from E__________, but their combined glow is one of the most
s__________________ features of the night sky.
Planets
Planets are very different from s_________. There are no nuclear explosions on the
p___________and so planets do not make their own l_________. Instead, they reflect light
falling on them from the S______. This allows us to see them in the night s______. They’re
seen as points of l___________ that look very much like real s_________. Although the
p_____________ of the solar system are far from Earth, they are much closer to us than the
S_________.
Mercury, Venus, Earth and M________ are the closest planets to the S_______. These are
known as terrestrial (meaning Earth-like) p______________. All these planets are rocky with
a hard s________________. Mercury, V______________, and Mars are relatively close to
Earth and are often seen in the night s_______ as a bright or colored point of l__________.
M________________ and Venus are usually visible before dawn as morning ‘s___________
‘or just before sunset as evening s__________. At these times, Venus is the
b________________ in the sky. Mars appears as a red-colored s____________. The outer
planets of Jupiter, Saturn, U_______________ and Neptune are huge balls of g__________
with a small and rocky c__________. For this reason, they are commonly known as the gas
g____________. While Jupiter and Saturn can be seen as ‘stars’ with the naked eye,
Neptune and Uranus can only be seen from E______________ using a t_______________.
Other things you might see.
Artificial satellites
Artificial s___________________ orbit (travel around) Earth, looking like “stars’’ travelling
slowly across the night s______________. They have been placed in orbit as space stations
and for purposes such as c____________________ and for observing the weather on
E_____________surface. The International Space Station (ISS) make sits own ___________
but this is too dull to be seen from E____________. You see satellites because they reflect
s____________________back to you.
Shooting Stars
You may have seen something that looks like a s________ shooting across the night
s______. Most fizzle out before they hit the horizon. These s______________ stars are
space debris or r___________ burning up in our atmosphere as they plunge towards
E____________.
A small rock or p______________ of debris in space is called a m_______________. They
can range in size from a g__________of sand to a rock 10 m__________ across.
Occasionally, the path of a m__________________will bring it close enough to Earth for it
to be pulled by Earth’s g____________. As the rock falls through the E__________
atmosphere, it reaches s___________ of more than 15 kilometers per s_____________! The
meteoroid quickly compresses the a_______ in front of it, causing the air to h__________
up.
This in turn h______________ up the rock, much like when your bicycle p____________
gets hot when you quickly pump up a t_____________.
The enormous heat generated turns the m________________into a blazing fireball known
as a meteor or shooting s_________. Most meteors are so s__________ that they burn up
completely in the a______________________. Therefore, most shooting s___________
fizzle out before they reach the g________________.
However, if a meteor is large then part of it might reach the g_____________ before it has
completely b__________ up. The part that reaches the ground is called a m_____________.
Most meteorites are s___________, but on very rare occasions E___________ is struck by a
l____________ meteorite. Occasionally, these large meteorites are asteroids that have
strayed from the asteroid belt. The
b___________ is a band of rocky
o____________ that orbit the S________
between Mars and J____________. The
destruction the meteorite causes depends on
its s_____________. Smaller meteorites form
craters while larger ones can have devastating
e____________. For example, there is a strong
evidence that a m___________ meteorite impact caused the e_________________of the
dinosaurs 65 m_________________ years ago.
Comets
C_______________ are part of the s__________ s___________ because they also travel
around the S_______. Comets don’t appear often but when they do, they are among the
most spectacular sights in the s_________. Comets are dirty snowballs made of i_____
mixed with c____________ dioxide and other s_________________. They have a head
known as a c_________ and a long shining t____________. One of the most famous
c______________ is Halley’s Comet. It reappears in the night s______ approximately every
76 y__________. Its most recent appearance was in ______________.