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What killed the dinosaurs and will it kill us too?. FIB Spring 2008. Perspective. Watch this clip and wonder…. Dino what?. What were dinosaurs? ‘Terrible lizards’ Reptiles of enormous variety
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What killed the dinosaurs and will it kill us too? FIB Spring 2008
Perspective Watch this clip and wonder…..
Dino what? • What were dinosaurs? • ‘Terrible lizards’ • Reptiles of enormous variety • Millions of years ago, long before there were any people, there were dinosaurs. Dinosaurs were kinds of prehistoric reptiles that lived during the Mesozoic Era, the "Age of Reptiles.” • Just the birds left now* *some think they co-evolved with the dinosaurs
How many dinosaurs species were there? Approximately 700 species have been named to date. Recent estimates suggest that about 700 to 900 more dinosaur genera may remain to be discovered. Or about 1000 to 5000 more species. Most dinosaur genera presently contain only one species (for example, Deinonychus) but some have more (for example, Iguanodon). Even if all of the roughly 700 published species are valid, their number is still less than one-tenth the number of currently known living bird species!
First Dinosaurs • Fossil Data - The last dinosaurs roamed the Earth about 65 million years ago. • Fossil Data - They ruled the Earth for some 150 million years before that time, or started about 215 mya. • That’s 150,000,000 years that the terrible lizards were around, folks! • What happened to them, all of a sudden?
Fact or Fiction • The truth is that no one knows for sure! • There are many theories… • The most popular are presented next…
Global cooling • The opposite of warming • The average temperature of the planet dropped • The result would be an ice age • Ocean level drops as water is deposited as snow and ice. • Food production slows due to cold temperatures
Volcanic activity • Volcanoes erupted and sent up lots of gases which produced a lot of changes • Green house gases = global warming • Soot = reduced sunlight = food shortage • Lava = localized heat and destruction
Meteor Impact • The most prominent theory claims that a simple chance collision of the Earth with a relatively small meteor was the cause. • A 10 mile wide rock traveling at 30,000 miles per hour slammed into the Yucatan region of Mexico
Questions to answer • What is the name of the asteroid? • Which date was the asteroid supposed to collide with a planet? • What was the ‘key hole’? • What will happen if the ‘key hole’ event took place? • What is a gravitation tractor?
Movies on meteors 1) Watch me first Watch me next! 3) Don’t scare me!
Meteor Impact • The initial shock wave killed many creatures within a few hundred miles • The main cause was the enormous amounts of debris (soil and rock) that was vaporized • This spread around the globe • Blocking out sunlight • No photosynthesis, meant no new plant growth • This resulted in the starvation of many species
Kill off • The main burden fell on the larger less equipped reptiles - the dinosaurs • They perished not at once but over many many years • The mammals which were second-class citizens of the planet before became the new dominate animal force
Proof for asteroid • We see lots of fossils of dinosaurs in regions around 65 million years old • Then we see no more of these • Instead we see a thin layer of iridium • Iridium is not native to Earth • It comes common to asteroids
What about us? What is our fate?
Mass Extinctions are common • The Earth has experienced mass extinctions 5 times so far, with a man-made one happening right now! • There are so many nice endings for us…
Movie 2 Mass Extinctions
Short term challenges • Disease • Pandemics from bacteria or viruses, or both • War • Nuclear winter • Climate Change • Changes to the biosphere • Stellar impact • Asteroids again or other cosmic events! • Other species • The rise of the octopus as the master race, or was that supposed to be the dolphins?
Long term outcomes • The previous may happen anytime from today up to a few million years from now! • However, on a greater time scale the odds favor other outcomes - that is if we are still around…!
The question is… • Would you prefer to be • fried, • frozen, • or dried to death?
Would you like to be fried, frozen, or dried to death, Sir? • At a recent meeting of the American Association for the Advancement of Science • People who publish Science Journal • ‘the third rock from the sun will either freeze or fry. Unless things simply dry up much sooner’ • How?…read on
Fried: The expanding furnace • Fact: the Sun shall not stay the same forever • About 5 billion years from now • It will become a red giant • It will be about 2000 times brighter • It will be about 100 times larger • "Earth will end up in the sun, vaporizing and blending its material with that of the sun," • "That part of the sun then blows away into space, so one might say Earth is cremated and the ashes are scattered into interstellar space."
How do we know this? • Observations on other stars in the Universe • We can see this has happened in the past, and is happening to stars the size of ours, now. • Fuel turnover in the Sun • As it burns up all its hydrogen it will shift to using helium in about 5 billion years… • Watch: http://library.thinkquest.org/25763/llifeofastar.htm Watch: Animation of Red Giant
Freeze: Cold as Hell! There is an alternative outcome if we are lucky! • We may get dragged out of the Solar System before the Sun burns the Earth • A passing star could pull the Earth out of its orbit into space, or a different orbit! • We would escape the ‘burn’, but we would freeze to death, as the temperature would plummet to way way below freezing point! • -270 degree Celsius • However, the Earth would survive longer under this scenario! We could live underground or in insulated structures!
Drip dry please According to some computer models:- • The Earth will not have to decide between a death from fire or cold. • It would dry to death well before burning due to the way the Sun becomes hotter • "The sun is getting brighter with time and that affects the Earth's climate," Kasting said. "Eventually temperatures will become high enough so that the oceans evaporate.” • We shall have little of no water left.
Blow me away! According to yet another model… • The heating of the earth will cause a dessert like landscape. • As Earth becomes a global desert, carbon dioxide levels are expected to drop. • At a certain level, which might be achieved in half a billion years, there would not be enough carbon dioxide to support photosynthesis, and most plants would die.
Bombardment! Fact: The Universe is a rough place! • We can detect massive explosions at regular intervals in many distant places • Should one of these happen in the neighborhood, we could be exposed to bombardment by electromagnetic radiation!
Bombardment • 1) Gamma radiation - Gamma Ray Bursts • 2) Super Nova • 3) Pulsars • 4) Black holes drifting past • 5) …..
Summary - At best… • The planet has about between • Half-a-billion years (500,000) to 5 billion years of time remaining • Unless, it is hit by a large asteroid first or zapped by cosmic radiation, or sucked into a Black Hole. • Then it could be curtains instantly!!!!!!!! • Write your will soon! I have some forms for sale today, starting at just $5 each. See me after!
Group Questions • What other ugly deaths can you think of for us? • How would you rather die? Why? • Is there any way that humans can escape any of the outcomes presented today? Will that option be available to all of us, or a select few? • Recap, how global warming killed off most life forms during the 4th great extinction. Write out the sequence of events as I outlined them. • Do you think the price of petrol will kill us first? Is that a sort of revenge of the Dinosaurs? Why has this statement some validity?
