New Mars Forums

Palomar

Member

From: USA

Registered: 2002-05-30

Posts: 9,734

Re: Earth:  A Pinball Machine?

http://www.livescience.com/forcesofnatu … s.html]3rd rock from the Sun does "the wave"

:laugh:  Interesting article.  :up:

--Cindy

---

We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

Shaun Barrett

Member

From: Cairns, Queensland, Australia

Registered: 2001-12-28

Posts: 2,843

Re: Earth:  A Pinball Machine?

Hmmm.
    I was aware that Earth's continental crust is thicker than the oceanic crust but I didn't realise the ratio is 7:1.
    The oceanic plates are disconcertingly thin! 

---

The word 'aerobics' came about when the gym instructors got together and said: If we're going to charge $10 an hour, we can't call it Jumping Up and Down.   - Rita Rudner

Palomar

Member

From: USA

Registered: 2002-05-30

Posts: 9,734

Re: Earth:  A Pinball Machine?

*One portion of the article which caught my attention:

The general rule of thumb is that the denser a material, the faster the seismic waves travel.

:hm:  Anyone care to try and explain this?  Brainiacs...calling all Brainiacs!

And geologists know that longer wavelengths penetrate deeper than shorter wavelengths (it's the same reason you hear the loud bass beat from a passing car but not the high frequencies.)

*Cool.

--Cindy

---

We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

Earthfirst

Member

From: Phoenix Arizona

Registered: 2002-09-25

Posts: 343

Re: Earth:  A Pinball Machine?

Sound, wave energy moves through denser thing faster. In space there no sound because there is no mater to pass the wave energy. So the more mater there is the faster sound can move because the atoms are closer together. Speed of sound is faster in water than air, like wise sound is fastist in solid rock. Fan you ever put your ear to a railroad track? if you did you can hear trains coming from miles away. Train robbers did this so there were ready to stop the train, they did not need a train times. It is just the basic property of sound, the speed of sound must really great in a nuetron star!
It is a good reason why the continental crust is thicker but less dense than oceanic crust. It would be a good thing is the land started to subduct under oceanic crust we would not have a home! Oceanic crust is made out of mafic basalt rocks that are dense and heavy, cont. are made out of lighter sedimentry, felsic, and metamorphic rocks. In plate tectonics when ocean plate and a cont. plate hit, the denser ocean plate subducts under the lighter cont. plate. The ocean plate melts because it has water in it, rises and comes out on the surface as volconas. It is called a continental volcanic arc. Examples are the Cascades, Andes, and Aeutin in Alsaka.

---

I love plants!