Monday, February 17, 2014

Solar System -- Good Educational Website

Check out the cool animated GIF of the solar system at this site below.  Also, you can mouseover items in the GIF and learn more.

Solar System Theory

Here is a nice lecture from Arizona State University on the Nebula Theory of the creation of the solar system.

III. Formation of the planets

  • The first solid particles were microscopic in size. They orbited the Sun in nearly circular orbits right next to each other, as the gas from which they condensed. Gently collisions allowed the flakes to stick together and make larger particles which, in turn, attracted more solid particles. This process is called accretion.
  • The objects formed by accretion are called planetesimals (small planets): they act as seeds for planet formation. At first, planetesimals were closely packed. They coalesced into larger objects, forming clumps of up to a few kilometers across in a few million years, a small time compared to the age of the solar system (movie).
  • Once planetesimals had grown to these sizes, collisions became destructive, making further growth more difficult (movie). Only the biggest planetesimals survived this fragmentation process and continued to slowly grow into protoplanets by accretion of planetesimals of similar composition.

Read more here:

Sunday, February 9, 2014

Where do we get our Power from?

Did you know that almost 50% of the electricity in the U.S. comes from coal?  About 20% is from nuclear power plants.  Check this charts out:

Read more here: