A Future "K/T" Asteroid Impact -Would the Human Species Survive?

We posted yesterday about NASA's Dawn mission, which will launch from Cape Canaveral July 7th, on a mission to study the "dwarf planets" Ceres and Vesta in the Asteroid Belt between Jupiter and Saturn.

Asteroids are believed to be the building blocks of planets - primordial relics left over from the formation of the Solar System 4.6 billion years ago.

We thought it would be a perfect follow up to examine what the scientific world thinks would happen to the human species and life on Earth in general if an asteroid the size of the one that created the famous K/T Event of 65 million years ago at the end of the Mesozoic Era that resulted in the extinction of the dinosaurs impacted our planet.

The general concensus is that any comet or asteroid greater than 20 kilometers in diameter that strikes the Earth will result in the complete annihilation of complex life - animals and higher plants. (The asteroid Vesta, for example, one of the destinations of the Dawn Mission, is the size of Arizona).

How many times in our galaxy alone has life finally evolved to the equivalent of our planets and animals on some far distant planet, only to be utterly destroyed by an impact? Galactic history suggests it might be a common occurance.

The first this to understand about the KT event is that is was absolutley enormous: an asteroid (or comet) six to 10 miles in diameter streaked through the Earth's athmosphere at 25,000 miles an hour and struck the Yucatan region of Mexico with the force of 100 megatons -the equivalent of one Hiroshima bomb for every person alive on Earth today. Not a pretty scenario!

Recent calculations show that our planet would go into another "Snowball Earth" event like the one that occurred 600 million years ago, when it is believed the oceans froze over (althought some scientists dispute this hypothesis -see link below).

While microbial bacteria might readily survive such calamitous impacts, our new understanding from the record of the Earth's mass extinctions clearly shows that plants and animals are very susceptible to extinction in the wake of an impact.

Impact rates depend on how many comets and asteroids exist in a particular planetary system. In general there is one major impact every million years -a mere blink of the eye in geological time. It also depends on how often those objects are perturbed from safe orbits that parallel the Earth's orbit to new, Earth-crossing orbits that might, sooner or later, result in a catastrophic K/T or Permian-type mass extinction.

What keeps the Earth "safe" at least the past 65 million years is the massive gravitational field of Jupiter, our cosmic guardian, with its stable circular orbit far from the sun, which assures a low number of impacts resulting in mass extinctions by sweeping up and scatters away most of the dangerous Earth-orbit-crossing comets and asteroids.

In 1995, astronomer George Wetherill calculated that without Jupiter, the impact rate on Earth by comets and asteroids would be 10,000 times higher. Under such bombardment it is hard to conceive of how complex life would survive.

Related Galaxy Posts

The Dawn Mission -NASA's Journey to the Beginning of the Solar System

The End of the World -A Video (the most terrifying short film ever!)

Past as Prelude -Asteroids & the Origin of LIfe (Includes "Impact Map of the World")

Comments

[Howie Modell]

Casey .. when did the Asteroid Belt move? It should be between Jupiter and Mars. :-)

Was it the work of Aliens?

[Stephen]

planets and animals

my guess: plants

My proposal is that even with very little warning, at least some humans would be smart enough to survive and preserve a small ecosystem's survival. One could live off canned food for months while thinking of solutions. I'm not saying it would be pretty. A K/T event will ruin your whole day.

[Stephen]

The first this to understand

My guess: thing.

Biosphere II - the failed attempt to have a self-sustaining ecosystem, could possibly be a model for post-impact survival. In a Sun-reduced climate, a power source would be needed for heat and light. This is technology we have. And, we might only need survival for a decade or so.

Humans have already modified the climate on Earth. It could be done again, if needed.

[Marty Ferguson]

I would hope that, barring any more stupid attitudes and intolerance between countries, man can work together to build LONG-TERM ORBITAL SPACE HABITATS TO HOUSE PEOPLE until the disaster is over and the earth has recovered. We can't save six-plus billion people, but how many die each day from one mundane source or another including suicide bombers and the Iraq War?

President Bush (or ANY nation's leader) should implement a long-range plan to build a space station (or stations LIKE ARTHUR C. CLARKE'S '2001:A SPACE ODYSSEY' design) that could support AT LEAST one billion people. The ISS is so tiny that I'd have to go outside to change my mind!

[emnkt]

i know k/t.

[emnkt]

that is a fact.

[K.Margiani]

Survival of mammals’ kingdom is closely connected to the size of asteroid!
Everything is explained in the excellent research;

New COSMOGEOLOGICAL THEORY and modern explanation about COSMOGEOLOGICAL CATASTROPHIC PLATE TECTONICS:
A GLOBAL FLOOD MODEL OF EARTH HISTORY
There is already began new epoch; epoch of Cosmogeological theory!

-Cosmogeological PLATE TECTONICS supports gradualism within peaceful periods only.
-Cosmogeological PLATE TECTONICS supports rapid drift (global oscillation) within few days, every 10000-12000 years. (Noah’s flood-Gilgamesh’s flood) Each similar flood is connected to the basinal extinctions.
-Cosmogeological PLATE TECTONICS supports rapid CATASTROPHIC PLATE TECTONICS after asteroid impacts and rapid EB geo-transfers (rapid movement of outer nucleus masses into asthenosphere). It produces rapid global movement of continental platforms and rapid subduction, obduction, overfolding thin lithosphere platforms. It means rapid global folding-rugosity almost all oceans’ platforms. Connected to the global extinction boundaries.

http://www.cosmogeology.ge/chapter-18.htm

Gilgamesh’s or Noah’s flood is already decoded!

[Anon]

You quote "100 megatons". The Soviets blew up a 50 megaton nuke already many years ago. While nasty, its nothing like the K/T issue. 100 megatons wouldn't dent humanity overall. I was under the impression that the K/T event was caused by a 100 teraton hit. Waaaay different.