Meteoroids! Asteroids! Comets!

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Meteoroids! Asteroids! Comets!

• Oh, my!

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What makes up our Solar System?

• The sun
• Planets
• Moons
• Asteroid belt (between Mars and Jupiter)
• Lots of space
• All sorts of bits and pieces of rock

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Meteorite, Meteoroid, Meteor? Whats the
difference?
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Meteorite vs. Meteoroid

• Meteoroid while in space a meteorite is called
  a meteoroid
• Meteorite a small rock or rocky grain that
  strikes Earths surface
• So the difference is just based on where the rock
  is when you are describing it

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Meteor

• Sometimes called a Shooting Star
• When a meteorite enters Earths atmosphere,
  friction causes them to burn up, producing a
  streak of light

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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

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Are they dangerous?

• Most meteoroids disintegrate before reaching the
  earth by burning up in Earths atmosphere
• Some leave a trail that lasts several minutes
• Meteoroids that reach the earth are called
  meteorites. Large ones can cause damage

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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
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Whats 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)

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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

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Comets
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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

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Famous Comets

• Comet Hale-Bopp
• Halleys Comet
• Comet Kohoutek

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A Comets Tail
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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

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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

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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?

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Near-Earth Asteroids (NEAs)

• At least 1000 asteroids orbit outside of the
  Asteroid Belt these could be a danger to Earth
• Asteroids that cross Earths 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

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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

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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?

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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

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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 Earths surface

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What do Scientists Think Happened

• Sunlight was blocked from reaching the Earths
  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)

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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.

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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.

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Torino Scale

• A system used to rate the hazard level of an
  object moving toward Earth

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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 Earths surface
• Meteor Shooting Star

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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.

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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.

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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.

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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 ______________.

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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.

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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

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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

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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