Tuesday, October 14, 2008

Earth Origins

This week we began a new unit discussing the origin of the Earth.  In order to understand Earth's origin, we first took a look at how the universe was created.  The Big Bang theory states that all of the matter in the universe was concentrated in one small mass that blew apart 10-20 billion years ago.  As that matter spread out, some of it collected in a central mass, contracted under its own gravity, condensed, and heated until forces were so strong that thermonuclear reactions began, thus creating the star that is the center of our solar system.  Some of the questions that we will be tackling this week are:
  • Why is Earth so well-suited for life?  What factors contribute to this?
  • What is Earth's revolution and what evidence do we have for it?


callieangelbuffy said...

It’s challenging for life to exist on other planets in our solor system because all the other planets don’t have the right temperatures because they are to close or to faraway from the sun. For life to exist anywhere it needs water and that is always found on other planets we also need an atmosphere thick enough to keep life alive and some carbon-based molecules.
The Earth is perfectly positioned 93 million miles from the sun (wow that’s a lot), the Earth's temperature range alowes the billions of chemical reactions that are needed for biological life to continue. All of the elements of our planet's position and the chemistry of it are also perfect for life. The speed of the earth's daily rotation on its axis, the annual elliptical path around the sun, its tilt (which causes the seasons) and the amoudnt of gravitational pull also create the perfect situations for life to live on Earth.

Dan Cunitz said...

Great response, Cassie. You picked up on many of the factors that influence life on this planet. A question, though, is whether or not all planets need those factors for life to occur. Here is a site that argues that Europa, one of Jupiter's moons, may have life forms underneath its frozen ocean: http://www.d.lane.btinternet.co.uk/Essay.htm

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