yes i know that scientist say that earth is hot from inside by seeing the volcanos lava and other planets in solar system.in our elementry books it is said that earth is made up core mantle crust.but we can cannot make firm theories by just looking at signs.i just want to know that its a reality based on fact or just a theory.
2006-07-05 23:52:47 · 11 answers · asked by orangevolution 2 in Science & Mathematics ➔ Earth Sciences & Geology
We know that the earth is made up of core, mantle, and crust based on scientific evidence and in part based on logical deductions. The core is by far what we know the least, specially its composition. Nevertheless, this is what we know:
Fact: The speed of the seismic waves increases with increasing density and rigidity.
Fact: Earthquakes propagates faster with increasing distance. Indicating than the density of the earth increases with depth.
Fact: P-waves (or primary waves) travels in solid and liquids.
Fact: S-waves (or secondary waves) can only travel in solids.
Fact: In seismic profiles the time that an earthquake travel there are marked jumps in speed defining several "layers" of similar speed.
Fact: There is a shadow zone where no S-waves are recorded. This suggests (proves) that the outer core is liquid but the inner core is solid.
The stimated density of the earth is 5.5 gr/cc but the average crust is only 2.7 gr/cc. The very few samples of the mantle that we have suggest a density of about 3.5 gr/cc. Suggesting that the core is even denser (it has to be a lot denser than 5.5 gr/cc to compensate for the mantle).
We don't know the exact composition of the core.
But based on the analyzed samples of meteorites it is widely accepted by the scientific community that it should be an alloy of iron and nickel plus other minor components. Just based on the density somebody (not a scientist) could argue that is made of gold or other rare metal. But this is absurd, there is no evidence for that, gold has a low abundance, and at the pressure and temperatures stimated at the center of the earth it would be all liquid, so it does not fit the data. So all the evidence points to a iron nickel alloy, eventhough the exact composition is not known.
2006-07-06 05:50:39 · answer #1 · answered by Scientist13905 3 · 0⤊ 0⤋
The interior of the earth is studied by both the rocks that ahre exposed at teh surface which are known to have been from the mantle, and by use of siesmic waves. The reason we know the outter core is liquid are two fold. The reaction of siesmic waves from the surface are those of a wave transitioning from a solid to a liquid (as can be replicated using water and a solid) and becasue of the earth's magnetic field (which is produced becasue the inner core is routating in a iron rich metal and is composed of metalic iron producing a huge electomagnetic system.) A siesmic wave generated on the surface (in the crust) travels down to the Moho (the transition zone from the crust to the mantle) and is refrected slightly becasue of the nature of the mantle being "plastic" (not solidly crystiline but not liquid), then the distortion associated with the outer core mantle transition and then the return trip. But it is in fact all based on sound scientific work and not guesses.
2006-07-19 06:59:02 · answer #2 · answered by Chewie 3 · 0⤊ 0⤋
Sound travels faster through dense materials and more slowly through less dense materials. At a boundary layer that divides two layers of sharply different density the sound is partly reflected by the interface.
There are earthquakes of varying intensity all over the earth, going constantly at any given time. These earthquakes cause seismic waves, which are just very low frequency sound. By analyzing data from seismometers geologists can use the seismic noise like the sonar of a bat to get a rough picture of what's beneath the earths surface.
Large seismic events can be used like the sonar ping of a submarine to get a sharper picture of the earths hidden inner structures.
Theories are based on facts, theories do not ever become facts in and of themselves. Theories are broad sketches of complex natural systems which explain the observable facts about said systems.
2006-07-06 05:17:00 · answer #3 · answered by corvis_9 5 · 0⤊ 0⤋
Actually, you are incredibly correct! The American Government once again has foisted another hoax on the American Public!
Man did not land on the Moon, Kennedy was not murdered by Oswald, and the center of the earth is actually made of Ben and Jerry's Very Cherry Garcia Ice Cream. It is a fact, I went there and ate it.
2006-07-14 17:10:57 · answer #4 · answered by AREYOUKIDDING? 1 · 0⤊ 0⤋
WE define the layers, as we make the rules. By placing exposive devices at various points on the earth, and seismographs at other points, we have determined the earth is separated into layers and have been able to determine their depths based on the spped of sound through certain phases of matter...go to wikepedia
2006-07-06 00:51:14 · answer #5 · answered by Anonymous · 0⤊ 0⤋
What Is Earth Composed Of
2017-01-01 06:16:20 · answer #6 · answered by ? 4 · 0⤊ 0⤋
To create the land we're living on. The Bible says the earth was water until God made the land.
2016-03-27 05:58:44 · answer #7 · answered by Anonymous · 0⤊ 0⤋
Scientist have not made the theories from signs. They have establised facts based upon seismological studies. .
2006-07-19 23:19:35 · answer #8 · answered by Anonymous · 0⤊ 0⤋
thats a good questin i mean hoe do we know theres not cottn candy ander the dirt.mmmmmm that would be so good maybe thats why were floating in space because we are so light from being filled with cotton candy! isnt that so cool. lol. ur right
2006-07-16 02:34:11 · answer #9 · answered by liz 3 · 0⤊ 0⤋
SOMETHING IS CAUSING THE HEAT,
2006-07-19 17:36:55 · answer #10 · answered by onelightsleeper 2 · 0⤊ 0⤋