How do we know all the layers and how deep each one is and if its solid or liquid? We never sent probes down there, and How do we know the composition and density of the core?
We have'nt even been to the bottom of Mariana Trench yet
2006-10-23 18:16:59 · 4 answers · asked by Scatman 5 in Science & Mathematics ➔ Earth Sciences & Geology
They use seismological data obtained from Earthquakes. Earthquakes produce two kinds of waves, P and S waves. P waves can travel through liquids and solids, but S waves can only travel through solids. Based on the fact that they never recieve S waves on the opposite side of the Earth from the source of the quake, they know that the interior contains at least some liquid. The size of this liquid layer, and the size of many layers can be determined by the amount of bending the wave experience. Waves bend differently depending on the density of the layer they are entering. Anyhow, there's a lot of physics behind it that I'm not going to get into, but essentially by measuring the origins and trajectories of these waves, they can deduce the structure of the interior of the Earth, but not very accurately, especially the deep interior.
2006-10-23 18:24:24 · answer #1 · answered by Anonymous · 1⤊ 0⤋
Geophysics and Seismology. The propagation of S-waves and P-waves tell us the density and phases of the various layers. And yes, we have been to the bottom of the Marianas Trench, with our little robot probes.
2006-10-24 12:41:06 · answer #2 · answered by Amphibolite 7 · 1⤊ 0⤋
Yea, we really not know more than Theories. Heck, many people think all those pictures by the Hubble Telescope are real, the colors are computer enhanced, that really not what they look like.
2006-10-24 01:28:21 · answer #3 · answered by Snaglefritz 7 · 1⤊ 0⤋
HOW DO WE KNOW HOW FAR AWAY THE SUN OR MOON IS.
WE CAN ECHO AND SOUND TEST. WE CAN SEE WITH RADAR AND SOUND WHEN WE CAN'T SEE WITH OUR EYES.
2006-10-24 01:24:55 · answer #4 · answered by cork 7 · 1⤊ 0⤋