Aerospace Dimensions
Module 5
Space Environment
Contents
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Chapter 1 – Space
Chapter 2 – The Solar System
Quiz
Credits
Chapter 1
Space
What is space?
Space is the region
beyond the immediate
influence of Earth and
it’s atmosphere, and is
defined by the Air Force
and by NASA as starting
at an altitude of 50
miles. Anyone who
reaches this height is
awarded astronaut’s
wings.
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Characteristics of Space
One of the major
characteristics of space is
that there’s no atmosphere,
and therein, no oxygen.
Because space is also a near
vacuum, there is very little
molecular movement,
meaning the temperature is
very, very low. The
temperature in space is
defined as absolute zero, or
the temperature at which
there is zero molecular
movement. The
temperature is -273°C.
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Characteristics of Space
Many people also think of
space as having 0 gravity.
No matter where you go
in the universe, there is
always gravity pulling on
you, which is why we call
the gravity in space,
microgravity, as it is much
smaller than when on the
surface of a celestial
body.
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Characteristics of Space
There are three general terms used
when describing distances in space:
cislunar, interplanetary, and
interstellar. When talking about
distances it’s also important to
remember that space is VERY big,
about 156 billion light-years to be
more precise, or, in other words,
936,000,000,000,000,000,000,000
(936 sextillion) miles across
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Characteristics of Space
Cislunar space is defined
as the region of space in
between the Earth and
the Moon, a distance of
about 237,087 miles.
Within cislunar space is
most of Earth’s
magnetosphere. As far as
space goes, cislunar space
is pretty crowded,
containing man-made
satellites, meteoroids and
even astronauts.
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Characteristics of Space
Interplanetary space is the
next step out from cislunar
space, and is the space
between our Sun, and the
orbit of the most distant
planet, which is Neptune.
Neptune’s orbit is approx.
2,799,300,000 miles from
the Sun, making
interplanetary space a
significantly large region
than cislunar space. This
region contains all 8
planets, their moons, the
asteroid belt, comets, as
well as charged particles
and magnetic fields.
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Characteristics of Space
Interstellar space is much,
much larger than
interplanetary space.
Interstellar space is the
region in between
different stars. The
nearest star to our Sun is
4.56 light years away,
meaning it’s
27,360,000,000,000 (27
trillion, 360 billion) miles
away.
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Celestial Bodies
There are a HUGE
number of different
types of celestial bodies
in our universe. If you
can think it up, and it’s
physically possible, then
somewhere in the
universe, it’s almost
definitely happened.
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Celestial Bodies
One celestial body most
people are familiar with is
a galaxy. Galaxies are
massive collections of
stars and gas and are
arranged in a few
different forms: elliptical,
spiral, and irregular.
Elliptical galaxies are oval
in shape, spiral galaxies
have spiraling arms
moving out from a bright
center, and irregular
galaxies have no
particular shape.
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Celestial Bodies
Another type of celestial
body is a nebula. Nebulae
are much smaller than
galaxies, in fact, many
nebulae are within
galaxies. A nebula is a
large cloud of gas and
dust. Nebulae are very
interesting as they are
where stars are born at –
using the dust and gas
they are made up of.
Many nebulae are the
remnants of a dying star.
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Celestial Bodies
Stars are also major
celestial bodies in our
universe, forming the
hubs around which solar
systems develop. Stars
are bodies of very hot
gasses such as hydrogen
and helium. Stars are also
gigantic tug-of-war games
between gravity and the
pressure pushing outward
from within the star from
the hot gasses.
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Celestial Bodies
Another formation we
use is a constellation of
stars. Constellations are
groupings of stars as we
see them from Earth.
Currently, there are 88
constellations we use
today. Many are named
after mythology. Many
people know
constellations such as
Orion or Ursa Major
(which contains the Big
Dipper).
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Space Around Earth
Space around Earth is
very active because the
atmosphere may end at
approx. 50 miles, but the
magnetosphere extends
much farther – starting at
about 215 miles above
Earth. Things such as the
aurora borealis and the
Van Allen radiation belts
are examples of what
interaction with the
magnetosphere causes.
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Space Around Earth
Most people know the
aurora borealis as the
‘Northern Lights.’ The
lights are caused by the
interaction of solar
particles with our
magnetosphere and can
occur from anywhere
between 60 to 600
miles above the surface
of the Earth.
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Space Around Earth
The area surrounding
Earth is not solely for
show however, the
Ionosphere is a critical
part of our atmosphere.
The Ionosphere contains
a large number of ions
that protect us from solar
radiation and cosmic rays
from around the universe.
The ionosphere also
reflects radio waves back
down to Earth – allowing
AM radios to travel very
long distances.
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Space Around Earth
Yet another key part of the
area surrounding Earth is
our magnetosphere. Our
magnetosphere doesn’t
begin until about 215 miles
above the surface, but it
extends are very long
distance – even further than
the Moon. The
magnetosphere combats a
large portion of solar
radiation, especially from
the solar wind and solar
flares.
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Space Around Earth
The area around Earth
can even be harmful to
astronauts. The Van Allen
radiation belts can cause
severe harm to
astronauts if they stay in
them too long –
fortunately, the shuttle
orbits beneath them. The
belts are caused by
charged particles from
the Sun becoming
trapped inside the
magnetosphere and
bounce around.
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Chapter 2
The Solar System
The Sun
The Sun is most important
body in our solar system. It
provides all of our energy
here on Earth as well as
being the center of our
solar system. The Sun is
approx. 93 million miles
from Earth and has a
diameter 100x bigger than
Earth’s. It is about 90%
hydrogen, 9% helium, as
well as other minor
elements. The surface is
also characteristically
violent and dynamic.
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The Sun
The surface of the Sun, also
known as the photosphere,
is so hot (about 10,000
degrees), that it’s in a
plasmatic state. Because of
this fluidity and the amount
of energy involved, many
solar disturbances can occur
such as sunspots, solar
flares, or solar
prominences. Sunspots are
the darker, cooler areas on
the Sun’s surface.
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It’s from these spots that
the prominences and flares
occur. Solar prominences
are large, long-lasting
energy discharges that can
reach out for thousands of
miles and last for months.
Flares are shorter lived, but
are more dangerous to us as
they spring up quicker and
give us less notice.
The Moon
Earth’s single moon
orbits in an elliptical
trajectory around the
Earth every 27 days.
The orbit goes from
about 252,000 miles
away to 221,000 miles
away. At 2,155 miles,
the Moon’s diameter is
only about a fourth of
Earth’s diameter.
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The Moon
The Moon’s surface is very
dry and barren, with no
atmosphere and no liquid
water. The surface is
primarily rock covered with
a fine layer of dust. There
are many different types of
rock on the Moon, but the
two most common are
Moon basalt and
anorthosite. The Moon’s
basalt is very similar to
Earth’s, but contains
different minerals. The
basaltic rocks make up the
dark portions of the surface.
Anorthosite however, is
relatively rare on Earth,
being only found in
Greenland. Anorthosite is
what the highlands (the
light areas) of the Moon are
covered with.
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Mercury
Mercury is the closest
planet to the Sun, being
only about 36 million miles
away from it. Because of
this close proximity,
Mercury’s year is only 88
Earth days. Mercury also
rotates very slowly on it’s
axis, making it’s day very
long – Mercury’s days are
approximately 59 Earth
days, meaning there’s less
than 2 Mercurian days per
year.
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Another result of it’s very
close proximity to the Sun is
it’s extreme temperatures.
On the day side of Mercury,
temperatures reach a
scorching 800 degrees,
while the night side drops
down to -300 degrees.
Mercury’s surface is also
very resembles that of the
Moon – it’s very rocky, and
heavily cratered as there is
no atmosphere on Mercury.
Venus
Venus is the planet closest
to Earth and is
approximately the same size
as Earth. Venus is 67 million
miles from the Sun and
takes 225 Earth days to
orbit it. The similarities with
Earth end here though.
Venus is an extremely hot
planet, due to it’s extreme
greenhouse gas effect –
temperatures all around the
planet are about 850
degrees.
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Venus’ surface cannot be
seen from Earth as it is
enveloped in a thick layer of
clouds that rotates around
the planet 4 times faster
than the planet rotates – a
Venusian day lasts about
243 Earth days, making it’s
year shorter than it’s days.
Venus’ atmosphere is
comprised of 96% carbon
dioxide, and 4% nitrogen, as
well as small amounts of
other materials.
Venus
It is believed that extreme
volcanic activity in the
past has caused these
thick sulfuric clouds that
cover the planet, these
clouds, along with the
large amount of carbon
dioxide in the
atmosphere, do not allow
heat to escape the planet,
raising the temperature
to very high levels.
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Venus is relatively
smooth, although it does
have some highlands and
craters. It is also very easy
to see Venus right before
the Sun sets at night and
before it rises in the
morning as it’s very bright
– much brighter than any
star or planet in the sky.
Venus
Venusian Cloud Tops
Venusian Surface
Earth
Earth, is the only known
planet that harbors life.
Our atmosphere is 78%
nitrogen, 21% oxygen,
and has small amounts of
argon, carbon dioxide,
and other gasses. The
atmosphere is very key to
having life on Earth as it
gives us the oxygen we
breathe, as well as
protecting us from solar
radiation.
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Our surface is 67%
completely covered in
water, with the Pacific
Ocean accounting for 50%
of that. There is a very
wide array of terrain
features as well as forms
of life on our planet. Our
years last 365 days and
our days last 24 hours.
Mars
Mars is the next planet from
the Sun after Earth. It’s red
in color due to the dust
covering the surface which
is primarily composed of
rust. Mars has a largely
barren landscape with a
very thin atmosphere
composed mostly of carbon
dioxide. Mars also has only
about have the gravity of
Earth, so massive dust
storms can begin, covering
much of the surface of Mars
at once.
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Mars is renowned for it’s
massive volcanoes – being
the planet that has the
biggest volcano (Olympus
Mons). Olympus Mons is
400 miles across, and is 17
miles tall (over 3 times taller
than Mt. Everest). Daytime
temperatures can reach as
high as 65 degrees, while
nighttime temperatures
drop down to as low as -130
degrees.
Mars
Martian days are only 37
minutes longer than Earth
days, however, Martian
years are nearly twice as
long at 687 Earth days.
Many probes have been
sent to Mars, such as
Viking I and II, Pathfinder,
Sojourner, Mariner, and
several others. Many
people believe that Mars
may have had life at one
point – and scientific
evidence does point to
that.
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However, conditions on
Mars now are not suitable
for life, as it has less than
1% of the pressure and
water on Earth.
Jupiter
Jupiter is our solar system’s
largest planet – having 3
times the mass of all the
other planets put together.
Jupiter is about 11x larger
than Earth. Jupiter’s days
last only about 10 hours,
and this very fast rotation
causes extreme weather
patterns. Jupiter is also the
first of the gas giants from
the Sun. Hydrogen is the
most prominent gas, making
up 90% of Jupiter.
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Helium, methane, and
ammonia are also present.
Jupiter’s cloud tops are
extremely dynamic and
have very high winds and
some of the biggest storms
in the solar system. The
biggest storm right now is
the Great Red Spot – which
is about 30,000 miles long
and 10,000 miles wide,
making it about the size of
our planet.
Jupiter
Jupiter also has many, many
moons. Currently, there are
16 known moons, 4 of
which are easily visible with
only a pair of high powered
binoculars. These four
moons are known as the
Galilean Moons as Galileo
was the first to see them
using his very crude
telescope. These moons are
very unique – one even has
large numbers of active
volcanoes (Io).
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Jupiter’s temperatures have
huge differences, with it
being about 60,000 degrees
in it’s core, to -220 degrees
on it’s cloud tops. Several
probes have been launched
past Jupiter, such as Pioneer
and Voyager.
Saturn
Most of us are familiar with
Saturn’s extensive ring
system. Saturn is the only
planet with such clearly
defined rings in our solar
system. The rings are made
from tiny particles to
particles are large as
boulders. The entire system
extends about 250,000
miles from the surface of
the planet. There are a total
of seven ring layers, the first
five discovered by Galileo
and the last two discovered
by the Pioneer spacecraft.
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Saturn itself is another gas
giant comprised mostly of
hydrogen and helium,
although not nearly as large
as Jupiter. Saturn’s days also
last about 10 hours but it’s
years are 29 Earth years
long. Like Jupiter, Saturn’s
very fast rotation also
causes very extreme
weather conditions on
Saturn’s cloud tops, with
winds known to reach 1,100
miles per hour.
Saturn
The temperatures on
Saturn are not quite as
extreme however, with
temperatures going up to
130 degrees during the
day to as low as -330
degrees during the night.
Night time temperatures
approach absolute zero
during the night, as
Saturn is nearly 900
million miles from the
Sun.
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Saturn also has an
extensive array of moons,
with 18 known moons.
One moon, Titan, is very
unique as it has it’s own
atmosphere – something
no other moon in our
solar system has.
Saturn
Titan
Uranus
Uranus is the third largest
planet in our solar system
and is another gas giant,
like Jupiter and Saturn.
It’s outer layers consist
primarily of hydrogen and
helium, as well as some
methane, which gives it
it’s blue-green color.
Uranus is approximately
1.6 billion miles from the
Sun – about twice as far
as Saturn.
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Uranus takes about 84
Earth years to orbit the
Sun, and rotates in 18
hours. However, Uranus’
axis is tilted to 60
degrees, meaning it’s
essentially tipped over on
it’s side. Because of this,
daylight is determined by
where it is on it’s orbit
around the Sun –
meaning there is about
42 years of daylight, and
42 years of night.
Uranus
Uranus has rings, like
Saturn, however, they are
very thin and are very
dark, so are hard to see.
Uranus also has about 15
moons. Because it is very
far from the Sun, Uranus
is very cold, with
temperatures dropping
down to about -340
degrees, nearly absolute
zero.
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Neptune
Neptune is the last gas
giant in our solar system,
and is the fourth largest
planet. Neptune wasn’t
discovered until 1846
using mathematics that
showed Uranus’ orbit was
being influenced by
another planet. Neptune
and Uranus are both very
similar to each other.
Neptune however, orbits
3 billion miles from the
Sun – a little over twice as
far as Uranus.
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Each of Neptune’s years
lasts 165 Earth years.
Neptune’s days however,
are only about 19 hours.
Like Uranus, Neptune’s
cloud tops are made
primarily of hydrogen and
helium, with a little
methane that gives
Neptune it’s blue color.
Neptune also has bright
white clouds of methane
ice crystal.
Neptune
Neptune also has a VERY
faint ring system. Like the
other gas giants,
Neptune’s weather is very
dynamic. In fact, Neptune
is the windiest planet in
the solar system – with
wind speeds recorded at
over 1,500 mph. Neptune
also has several large
‘dark spots’ – similar to
Jupiter’s Great Red Spot.
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Neptune also has the
Great Dark Spot, which is
a storm similar to the
Great Red Spot and is also
about the size of Earth.
Neptune has 8 moons
and on it’s largest moon,
Triton, temperatures of 391 degrees have been
recorded – very close to
absolute zero.
Neptune
Triton is about ¾ the
size of Earth’s moon
and orbits Neptune in
5.875 Earth days.
Voyager 2 also showed
active geysers on Triton
spewing nitrogen gas
and dark dust particles
several kilometers into
space.
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Pluto
*Disclaimer*
Pluto was recently classified in recent years as a
dwarf planet by the International Astronomic
Union. For the purposes of your tests
however, it is still a planet as the tests were
designed before it was designated a dwarf
planet.
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Pluto
Pluto was discovered in
1930, and there is still
very little known about it.
It’s yellowish in color and
it’s days last about 6.5
Earth days. Pluto is also
the smallest of our
planets, and the farthest
from the Sun at 4 billion
miles away. Pluto is dark,
and frozen. It has a rocky
core with a water and ice
mantle and a surface of
methane frost.
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Pluto also has one moon,
Charon, that is half the
size of Pluto. Charon’s
rotational period is the
same as Pluto’s so they
travel in a synchronous
orbit, although spinning
in opposite directions.
Pluto’s odd orbit around
the Sun also sometimes
puts it closer to the Sun
than Neptune.
Pluto
This is what Pluto and
Charon are thought to
look like – even the best
pictures of them show
no details as they are so
far away, so small, and
receive such little light.
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Asteroids
Asteroids are chunks of
rock that can vary in size
greatly – from tiny dust
particles to a few that are
a few hundred miles
across. Most of our solar
system’s asteroids are
located in the asteroid
belt – in between Mars
and Jupiter. Asteroids
were first discovered in
1801 by an Italian
astronomer and since
then, over 15,000 have
been cataloged.
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We know there are
probably millions more,
however. Scientists know
of about 200 asteroids
that are capable of hitting
us, but the closest any of
them come is 100,000
miles of us. Asteroids
come in all shapes and
sizes, and are composed
of any number of
materials.
Comets
Comets are commonly
described as ‘dirty
snowballs.’ They are
irregular in shape and have
a tiny nucleus made of
frozen gasses, water, dust,
and ice. Comets are
generally a few miles across
and usually travel around
the outer regions of our
solar system. Sometimes
they are bumped out of
their orbits by passing stars
and sent towards the Sun
however.
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As they get closer to the
Sun, they form a tail of
vaporizing gasses and ice,
forming the comets we see
here on Earth. These tails
can extend for millions of
miles. Comets sometimes
don’t completely burn up as
they travel towards the Sun,
many make several orbits,
such as Halley’s comet,
which appears every 76
years.
Halley’s Comet
Meteorites
Meteorites are relatively
uncommon due to our
thick atmosphere.
However, when ever a
meteor (objects entering
our atmosphere) hit the
surface, they are called
meteorites. We see
meteors here on Earth as
‘shooting stars.’ Most
meteorites are quite
small, only about the size
of a basketball usually.
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This is due to the
atmosphere burning off
most of the material.
Meteorites come from all
around the solar system,
some are proven to be
from Mars, some are
from the Moon – the
potential origins can be
anywhere.
Quiz
Question 1
Enormous collections of
stars arranged in a
particular shape are
called?
A)
B)
C)
D)
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Nebulae
Supernovae
Constellations
Galaxies
Correct!
Enormous collections of
stars, dust, and gas
arranged in a particular
shape are called
galaxies.
Next Question
Incorrect
Enormous collections
of stars, dust, and gas
arranged in a particular
shape are called
galaxies.
Next Question
Question 2
Groupings of stars as
we see them from
Earth, usually named
after mythology, are
called what?
A)
B)
C)
D)
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Binary Clusters
Constellations
Globular Clusters
Asteroids
Correct!
Groupings of stars as
we see them from
Earth, which are usually
named after mythology,
are known as
constellations.
Next Question
Incorrect
Groupings of stars as
we see them from
Earth, which are usually
named after mythology,
are known as
constellations.
Next Question
Question 3
Stars are bodies of
extremely hot gasses.
What are the gasses
stars are mostly
comprised of?
A)
B)
C)
D)
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Iron and Nitrogen
Hydrogen and Helium
Oxygen and Carbon
Hydrogen and Neon
Correct!
Stars are typically
comprised of mostly
hydrogen and helium.
Next Question
Incorrect
Stars are typically
comprised of mostly
hydrogen and helium.
Next Question
Question 4
What kind of gravity is
in space?
A)
B)
C)
D)
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Newtonian gravity
Universal gravity
Astrogravity
Microgravity
Correct!
The amount of gravity
in space is not zero,
rather, it is known as
microgravity.
Next Question
Incorrect
The amount of gravity
in space is not zero,
rather, it is known as
microgravity.
Next Question
Question 5
When referring to
something in cislunar
space, where is that
object at?
A) Between Earth and
Mars
B) Between Earth and
the Moon
C) Between the Sun and
Pluto
D) Between the Sun and
Alpha Centauri
Contents
Correct!
Something in cislunar
space is somewhere in
between the Moon and
Earth.
Next Question
Incorrect
Something in cislunar
space is somewhere in
between the Moon and
Earth.
Next Question
Question 6
What is a solar system?
A) A small, icy body
orbiting the Sun
B) The Sun and the
bodies that orbit it
C) Solar weather patterns
D) Darker, cooler areas on
the Sun
Contents
Correct!
A solar system is a sun
and the bodies that
orbit around it.
Next Question
Incorrect
A solar system is a sun
and the bodies that
orbit around it.
Next Question
Question 7
What is a meteor called
once it hits the surface?
A)
B)
C)
D)
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Meteoroid
Meteoroidic Object
Meteorite
Asteroid
Correct!
Meteors that hit Earth’s
surface are then called
meteorites.
Next Question
Incorrect
Meteors that hit Earth’s
surface are then called
meteorites.
Next Question
Question 8
Which planet is the last
gas giant from the Sun?
A)
B)
C)
D)
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Mars
Jupiter
Mercury
Neptune
Correct!
The last gas giant from
the Sun is Neptune
Next Question
Incorrect
The last gas giant from
the Sun is Neptune
Next Question
Question 9
Which planet is the
largest planet in our
solar system?
A)
B)
C)
D)
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Jupiter
Earth
Saturn
Venus
Correct!
The largest planet in our
solar system is Jupiter.
Next Question
Incorrect
The largest planet in our
solar system is Jupiter.
Next Question
Question 10
Why is Venus so hot?
A)
B)
C)
D)
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Volcanoes
Greenhouse Gasses
Heat is trapped
All of the above
Correct!
Venus is so hot because
volcanism in it’s past
released large amounts
of greenhouse gasses,
making heat become
trapped in it’s
atmosphere.
Contents
Credits
Incorrect
Venus is so hot because
volcanism in it’s past
released large amounts
of greenhouse gasses,
making heat become
trapped in it’s
atmosphere.
Contents
Credits
Credits
• Created by Cadet Ryan Stanley
• Based on Aerospace Dimensions Module 5:
Space Environment
Contents