How did the world actually appear?

Question

Cause ever since I was little, people keep giving me all kinds of different answers, and I know that there is no secure answer, but what is the most popular version (preferably not religious)?

My little brother just asked me, and I would really like to be able to share my extensive knowledge with him !! =)

Answer 1

Start with Carl Sagan's description "We are all made of star stuff."

The short version is:

"Earth, along with the other planets, is believed to have been born 4.5 billion years ago as a solidified cloud of dust and gases left over from the creation of the Sun. For perhaps 500 million years, the interior of Earth stayed solid and relatively cool, perhaps 2,000°F. The main ingredients, according to the best available evidence, were iron and silicates, with small amounts of other elements, some of them radioactive"

http://www.infoplease.com/ipa/A0004438.h...

If you look at pictures of spiral galaxies, this for example:

http://www.jwst.nasa.gov/images/Spitzer_...

You get a glimpse of what the early solar system looked like.

When your brother asks for more, check the links below <G>

Answer 2

The process is called accretion.  Dust particles and gas crash together forming larger particles, then rocks, then planetoids.  At some point, gravity is holding the particles together.  A large-enough object circling a star is classified as a planet.

It's like making a snowball.  You pat on additional snow to the outside of the snowball and it gets bigger.

The thing is, that while debris crashing onto the outside of an object, it can also cause the object to break apart.  The moon was formed when an asteroid hit the Earth off-center, and about 1/4 of its mass broke away.  If the hit had been on-center, well...

The current debate is how quickly accretion occurs.

Answer 3

god created it.

u could read this in the wholy books.

Answer 4

Via the magic of astro-physics.