Is there Intelligent Life on the Earth

Evolution of Intelligence:

• We know little about this
• We do know that the brain size of mammals has slowly increased over geologic time
• Brain size is proportional to body weight Life:

Define Relative Intelligence:

• Amount of brain tissue in excess of that required for basic body function
• This is known as Encephalization level (EL)

  

• P = body mass; EL is basically measured by K
• K can be recovered from the fossil record to some extent

What is Intelligence?:

• Biological Intelligence: environmental conditions determine the rate of growth of intelligence
• Artificial Intelligence: number of neurons basically correlates with learning ability

EL Scale

The point of this scale is one of RELATIVE intelligence --> there is nothing absolute about it.

Causes of Mass Extinction (Dinosaurs/Plankton)

Clearly are the result in reducing the amount of sunlight that reaches the surface.

Possible Mechanisms of Extinction

What do we know about the last extinction event 65 million years ago?

• We know there was an impact event
• The impact site was the Yucatan Penisula
• We know the dinosaurs became extinct at this time
• We know that much of the plankton became extinct

But we don't know the causal connection between the impact and the extinction cycle but clearly something basically put a halt to photosynthesis for some period of time.

Possibilities for blocking out the sunlight:

• Sulfur Clouds that Persisted? --> this is a recent theory, perhaps somewhat farfetched. There might also be a component of acid rain from this event that could have harmed much of the plant life that large plant-eaters fed on.

• Dust ejecta from the impact --> problem is that the residence time of dust in the atmosphere is fairly short

• Soot from global forest fire induced by the impact --> this is more promising as soot is very fine particulate matter that will find its way to the strasophere where the residence time is long

When will the next mass extinction event happen? (one of course could argue that its happening now)

Sometime in the next few 10's of millions of years the earth is likely to be hit again but an object 10--100 kilometers in diameter.

Learn More about NEAR EARTH OBJECTS

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The Electronic Universe Project

e-mail: nuts@moo.uoregon.edu