Download Meteoroids! Asteroids! Comets!

Meteoroids! Asteroids!
Comets!
Oh, my!
What makes up our Solar System?
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The sun
Planets
Moons
Asteroid belt (between Mars and Jupiter)
Lots of space
All sorts of bits and pieces of rock
Meteorite, Meteoroid, Meteor?
What’s the difference?
Meteorite vs. Meteoroid
•  Meteoroid = while in space a meteorite is
called a meteoroid
•  Meteorite = a small rock or rocky grain that
strikes Earth’s surface
•  So the difference is just based on where
the rock is when you are describing it
Meteor
•  Sometimes called a
“Shooting Star”
•  When a meteorite
enters Earth’s
atmosphere, friction
causes them to burn
up, producing a
streak of light
Where do they come from?
How big are they?
•  Pieces of rock that broke off other objects
•  Sizes range from as small as a pebble or
as big as a huge boulder
Are they dangerous?
•  Most meteoroids disintegrate before
reaching the earth by burning up in
Earth’s atmosphere
•  Some leave a trail that lasts several
minutes
•  Meteoroids that reach the earth are called
meteorites. Large ones can cause
damage
Flagstaff, Arizona
•  49,000 years ago
•  Meteorite about 150
feet in diameter
•  Weighed 650 pounds
•  Energy = 2.5 million
tons of dynamite
•  4000 feet wide, 650
feet deep
•  Still visible today
Barringer Meteorite Crater
What’s a “Meteor Shower”?
•  Usual rate = six meteors per hour
•  During a Meteor Shower = rate may be as
high as 60 meteors per hour
•  Occur when Earth passes through the tail
or debris of a comet
•  Presides (mid-August)
•  Leonids (mid-November)
Comets
•  Bodies in space made up of ice, dust,
small gritty particles
•  Sometimes called “dirty snowballs”
•  When close to the sun, ice vaporizes,
producing a spectacular streak of gas,
referred to as a “tail”
•  Many in a regular orbit around the sun
Comets
Where do comets come from?
•  Many ordinate in a region called the Oort
cloud which is located beyond the orbit of
the dwarf planet Pluto
•  Others originate in the Kuiper Belt beyond
the orbit of Neptune
•  This region is filled with billions of comets
Famous Comets
•  Comet Hale-Bopp
•  Halley’s Comet
•  Comet Kohoutek
A Comet’s Tail
Asteroids
•  An irregularly shaped
rocky object in space
(like a space potato)
•  May be the shattered
remains of objects left
over from the time
when the planets
were formed
How big are asteroids?
•  Larger than meteoroids
•  (In fact, the main difference between
meteoroids and asteroids is their size.)
•  Size ranges from 10 feet across to bigger
than a mountain
Asteroids
•  Approx. 150,000 asteroids in the Solar
System
•  Most are in a band that orbit the sun
between Mars and Jupiter (Asteroid Belt)
•  Why are there all of those asteroids
between Mars and Jupiter and not another
planet?
Near-Earth Asteroids (NEAs)
•  At least 1000 asteroids orbit outside of the
Asteroid Belt – these could be a danger to
Earth
•  Asteroids that cross Earth’s orbit are
called Near-Earth Asteroids or NEAs
•  NEA / Earth collision not likely
•  But if it did, the affect of the impact would
depend on the size of the asteroid
Large Asteroid hits Earth
65 Million Years Ago
•  Catastrophic Collision
•  Asteroid 6 to 12 miles
in diameter
•  Near the Yucatan
Peninsula in the Gulf
of Mexico
Large Asteroid hits Earth
65 Million Years Ago
•  Collision produced an explosion =
100 trillion tons of dynamite
•  Gouged out a crater about 60 miles in
diameter
•  How would an event like this affect Earth?
What do Scientists Think
Happened?
•  Forests were wiped clean for a distance of
300 to 600 miles in all directions
•  300 foot wave struck the coast of Texas
•  Powerful Earthquakes
•  Landslides destroyed long stretches of
coastline
What do Scientists Think
Happened
•  Explosion threw huge amounts of debris
into the air, covering large parts of North
America
•  Poisonous gases and dust soared high
into the atmosphere, spread over most of
the Earth, and then fell back onto the
Earth’s surface
What do Scientists Think
Happened
•  Sunlight was blocked from reaching the
Earth’s surface for many months
•  Temperatures plummeted to the freezing
point in normally warm areas
•  Not enough sunlight for photosynthesis
•  Plants died . . . Animals died
•  Many animals became extinct (including
many types of dinosaurs)
The Rise and Fall of Life on Earth
•  See the dip around 65 Million years ago?
•  This represents the extinction of about 75% of all
the species alive at that time.
Is the Earth in danger of a large
asteroid impact?
•  Not that we know of!
•  None of the asteroids or comets
discovered so far is on a collision course
with Earth.
•  However, we can't speak for those that are
not yet discovered. In principle, one of
those could hit any time, but statistically
the chances are very small.
Torino Scale
•  A system used to rate the hazard level of
an object moving toward Earth
Review
•  Q: What is the difference between a
meteoroid, meteororite, and a meteor?
•  Meteoroid = while in space a meteorite is
called a meteoroid
•  Meteorite = a small rock or rocky grain that
strikes Earth’s surface
•  Meteor = “Shooting Star”
Review
•  Q: What is the difference between an
asteroid and a meteoroid?
•  The main difference is the size of the
object.
•  Q: Which is larger, asteroid or meteoroid?
•  Asteroids are larger than meteoroids.
Review
•  Q: Why is it important to study smaller
bodies in our Solar System such as
comets or asteroids?
•  They help us learn about the history of our
Solar System.
Review
•  Q: Why do planets and moons with
atmospheres have less impact craters
than those without atmospheres?
•  The atmosphere slows and burns smaller
objects like meteorites, thus many do not
reach the surface to create an impact.
Review
•  Bright streaks of light that result when
rocky bodies burn up in the atmosphere
are called ___________.
•  Frozen bodies made of ice, rock, and dust,
sometimes called “dirty snowballs” are
called _____________.
•  Small, rocky bodies that revolve around
the sun are called ______________.
Review
•  Bright streaks of light that result when
rocky bodies burn up in the atmosphere
are called meteors.
•  Frozen bodies made of ice, rock, and dust,
sometimes called “dirty snowballs” are
called comets.
•  Small, rocky bodies that revolve around
the sun are called asteroids.
Review
•  Q: Discus what could happen if the Earth
experienced another large asteroid impact.
How would it affect life on Earth?
•  Forests flattened for many miles
•  If asteroid landed in water, it would cause
giant waves and landslides
•  Powerful Earthquakes
The devastation continues…
•  Poisonous gases and dust fills the
atmosphere, blocks out the sun
•  Temperatures drop drastically
•  No photosynthesis = plants die = animals
die
•  Some animals become extinct
Review
•  Q: Where is the Asteroid Belt?
•  Asteroid Belt is between Mars and Jupiter
•  Q: What is the Torino Scale?
•  A system used to rate the hazard level of
an object moving toward Earth