A presentation about meteors and observing them that was given at the Deer Flat NWR.

1. Meteor Showers

2. Meteor Science is a new Science
• Earliest reference by Chinese astronomers in
1809 BC
• Not scientifically believed to exist until the great
Leonid meteor shower of November 1833
• Many Americans observed 1,000 meteors per
hour during the Leonids
“I would more easily believe that (a) Yankee
professor would lie than that stones would fall
from the heavens”
- Thomas Jefferson

3. What is a Meteor
• Rocky material in space is called a
meteoroid
• Rocky material entering the atmosphere is
called a meteor
• Rocky material surviving long enough to
land on the ground is called a meteorite

4. What is a Meteor
• Meteors become visible 50 to 60 miles above
the ground
• Most meteors are only the size of a grain of sand
or a pebble
• Meteors are fast, between 11 and 70 miles per
second
• Meteors glow brightly as they streak across the
sky (lasting for only a few seconds)
• Most cease to exist tens of miles above the
ground
• Average of seven meteors per hour (sporadics)

5. Big Surprise
• A meteor’s emission of light is not due
to friction

6. Hypersonic Reentry
• Hypersonic reentry creates shockwaves in
the rarified upper atmosphere
• Shockwaves occur when a meteoroid
slams into air molecules faster than they
can move out of its way (which is the
definition of the speed of sound)

7. Hypersonic Reentry
• Shockwaves heat the atmosphere to
3,000O F
• Air this hot glows
• The hot shockwave ahead of the
meteoroid roasts the meteoroid
• A melting/vaporizing meteor also glows,
but represent only 5% of the meteor’s light

9. Extreme Meteors
• Very bright meteors (brighter than Venus)
are called Fireballs
• Exploding meteors are called Bolides
• Fireballs and Bolides imply very large
meteoroid bodies

10. Sources of Meteors
• Comet dust is the source for most annual
showers
• Asteroids are the best source for
meteorites found on the ground

12. What is a Meteor Shower
• Trails of billions of tiny meteoroids orbit
the sun
• Each trail is like a closed ring circling the
sun
• These rings are called meteor streams
• There are more than 80 different meteor
streams orbiting the sun
• Each stream has a different size, shape,
and tilt

13. When do Meteor Showers Occur
• Meteor showers occur where meteor
streams and Earth intersect
• This usually occurs once per year for each
stream
• Each shower can last for days

14. Observing Meteor Showers
• Dress warmly (even in summer)
• Observe at a dark location away from
lights
• Observe when the moon is below the
horizon
• Usually best observed after midnight
(when we face into Earth’s direction of
travel around the sun)
• Look away from the radiant

15. Radiant
• The point in the sky where meteors in a
single shower appear to originate
• Controlled by orientation of the meteor
stream relative to Earth

16. Popular Meteor Showers
•
•
•
•
•
•
Quadrantids: 2-3 January
Lyrids: 20-21 April
Perseids: 12-13 August
Orionids: 20-21 October
Leonids: 17-18 November
Geminids: 13-14 December

17. Four Notable Meteors
• KT Event (Cretaceous-Paleogene
extinction event)
• Tunguska
• Chelyabinsk Meteor
• First extraterrestrial meteor shower

18. The K-T Event
• 66 MYA
• 75% of all species went extinct
• We are here today because dinosaurs did
not have a space program

19. Tunguska Event (1908)
• June 30, 1908
• Sparsely occupied part of Siberia
• Meteor exploded with the force of 12 MT
(hydrogen bomb power)

20. Chelyabinsk Meteor
• February 2013
• Widely recorded on dash cams
• The sonic boom broke windows and
collapsed a building roof
• About 50 people hospitalized for cuts

21. First Extraterrestrial meteor Shower
• March 7, 2004
• Spirit Mars Rover

22. Meteorites