Impacts from Above. Mass Extinctions: Death and Destruction

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Ernest Sherman
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1 Impacts from Above 50,000 yr old Meteor Crater, AZ Watching the skies for potential catastrophes Mass Extinctions: Death and Destruction

2 Five Big Mass Extinctions When (End of ) ~440 Myrs Ordovician ~360 Myrs Devonian 251 Myrs Permian 205 Myrs Triassic 65 Myrs Cretaceous *Went extinct, **From Jablonski (1991,1995) Species Major Loses to Loss** 85 ±3% Brachiopods & bryozoans 83 ± 4% Rugose & tabulate corals, armored* & jawless fish 95 ± 2% All life! - Trilobites*, corals*, blastoids* 80 ± 4% Most synapsids 76 ± 5% Dinosaurs, marine reptiles, ammonites* Causes of Mass Extinctions Major and rapid environmental change - to fast for species to adapt Such as: Meteorite impacts Massive global eruptions Rapid climate change Major sea level fluctuations Nearby supernova event Ultimate Natural Disasters

3 Case Study in End Times: K-T Extinction 65 Million yrs ago 10 km rocky object Evidence Iridium Shocked Quartz

4 The Impact Site 180 km What Happened? Immediate Area 1. Tsunami & Fallout 2. Total destruction Global Effects 1. Darkness - decrease in photosynthesis 2. Cold (2-3 Months of -20 C) 3. Followed by Greenhouse warming 4. Acid Rain 5. Wildfires 6. Toxic Seawater

What types of things hit us? What happens when they hit us?

5 More Recently, 1994: Comet Shoemaker-Levy At least 21 fragments (2km) Large Impacts What is out there - what could hit us? What types of things hit us? What happens when they hit us? What do we do to prepare? How do we watch for potential objects? What do we do if we see one?

Dwarf Planets Pluto Ceres Eris Pluto and Charon A "dwarf planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its

6 Planets (1) A "planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit. Dwarf Planets Pluto Ceres Eris Pluto and Charon A "dwarf planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, (c) has not cleared the neighborhood around its orbit, and (d) is not a satellite.

Largest Dwarf 2003UB313 Discovered July 2005 97 AU

dust particle Toutatis (3) All other objects except

7 Largest Dwarf 2003UB313 Discovered July AU 1-1.5x size of Pluto? Eris Small Solar System Objects: Asteroids and Comets, Meteoroids, Interplanetary Dust 10 micron dust particle Toutatis (3) All other objects except satellites orbiting the Sun shall be referred to collectively as "Small Solar-System Bodies".

Planet Fragmentation Ejection from the Solar System Preservation Phobos

8 Fate of Small Bodies Collision with the Sun Collision with a Planet Capture by a Planet Fragmentation Ejection from the Solar System Preservation Fate of Small Bodies Collision with the Sun Collision with a Planet Capture by a Planet Fragmentation Ejection from the Solar System Preservation Phobos Deimos Gaspra

Fate of Small Bodies Collision with the Sun Collision with a Planet Capture by a Planet Fragmentation Ejection from the Solar System Preservation Source of Meteorites

9 Fate of Small Bodies Collision with the Sun Collision with a Planet Capture by a Planet Fragmentation Ejection from the Solar System Preservation Source of Meteorites Fate of Small Bodies Collision with the Sun Collision with a Planet Capture by a Planet Fragmentation Ejection from the Solar System Oort Cloud Preservation Earth Jupiter

10 Oort Cloud Jan Hendrick Oort Fate of Small Bodies Collision with the Sun Collision with a Planet Capture by a Planet Fragmentation Ejection from the Solar System Preservation Main Asteroid Belt Kuiper Belt Earth Jupiter

11 Our Main Threat: Asteroids & Comets 250 m elevation NEAR Spacecraft Eros

12 Major Asteroid Groups Near Earth Asteroids < 1 AU-2 AU Earth crossing Orbit Main Belt 2-4 AU Between Mars and Jupiter Centaurs AU Outer Solar System AU = Astronomical Unit (Distance from Sun to Earth) Main Asteroid Belt Mathilde & Eros (NEAR)

13 Kleopatra Gaspera Ida and it s moon Dactyl (Galileo) Near Earth Asteroids Itokawa 600m Hayabusa

Near Earth Asteroids (NEA s): As of November 24, 27, 2008: 2009: 5865

than year 1 ago) year ago) 997 1079 are are currently classified as

14 Near Earth Asteroids (NEA s): As of November 24, 27, 2008: 2009: NEA s are known (almost (again almost 1000 more 1000 than more 1 than year 1 ago) year ago) are are currently classified as as Potentially Hazardous Asteroids (PHAs) Near Earth Asteroids (NEA s):

15 Comets Icy Objects from the outer solar system Comet McNaught (January 2007) Nucleus of Comet Wild 2 Comets = Perturbed Kuiper Belt and Oort Cloud Objects

16 Comet Temple-1 Deep Impact

17 Comets come from: Kuiper Belt (& Oort Cloud) Gerald Kuiper Comet Hale-Bopp Meteor Showers 1833 England Leonid Meteor Shower

18 Meteorites Peekskill (NY) Fall, Oct. 9, 1992 Terminology Meteoroid Meteor & Meteor Shower Fall & Finds Meteorite Meteorite Finds: Antarctica

19 Types of Meteorites (Falls) Stones Carbonaceous Chondrites Ordinary Chondrites 5% 86% Achondrites 9% Irons 4% Stony-Irons 1% Chondrite

20 Chondrules under a scope X-Ray Image Chondrites Ordinary Carbonaceous

21 Achondrite - Stony Meterorite A stone from the Stannern eucrite shower that fell over Moravia, Czech Republic in Achondrites: Eucrites

22 Iron Meteorite Structure in Iron Meteorite

23 Hoba Meteorite Iron 55,000 kg Namibia (1920) ~88,000 yrs old 15.5 tons Largest in the US iron Willamette Valley Meteorite

24 Stony-Iron: Palasite Olivine Iron Meteorite Features: Fusion Crust & Magnetic Attraction Carbonaceous Chondrite - Nevada

25 Meteorite Features: Smooth Surface w/ Thumb Prints Source of Meteorites Irons Stony-Irons

26 Meteorite Impacts Crater Formation

27 Central Peak Ejecta Blanket

28 Ray Formation Tycho

29 Large impacts can eject material into space Lunar Meteorites

30 Martian Meteorites - SNC s Crater Types Simple Crater - Meteor Crater, AZ Crater Chains - Moon Complex Crater - Tycho Crater, Moon

31 Crater Types (cont.) Multiring Crater - Orientale Basin (Moon) Some Earth Craters (Shuttle Images) Chad, 17 km Several 100 Myrs ago Namibia, 2.5 km 5 Myrs ago

32 Manicouagan Crater, Quebec 214 Myr ago 70 km crater What was the largest impact in the United States in the last 100 Myr? Chesapeake Bay 35 Myr ago 3-5 km object

33 Another big one Manson, Iowa 74 Myr ago 3 km object Not all hit the Ground - Fireballs (Airbursts)

34 Tunguska, m stony meteorite 400Km - Hartmann

Solar System Debris. Asteroids 11/28/2010. Large rocky debris orbiting the Sun. Ceres, the largest asteroid. Discovering Asteroids

Solar System Debris. Asteroids 11/28/2010. Large rocky debris orbiting the Sun. Ceres, the largest asteroid. Discovering Asteroids Solar System Debris Material leftover from the formation of the Solar System Gives important clues about its origin Composition: Asteroids and Meteoroids: rock and iron Comets: ice and dust The basic building