How is it we know the earth's core is solid iron and nickel?

Answer 1

the earth's outer core is liquid. the inner core is solid and we know that because of earthquakes. When earthquakes occur, two kinds of waves spread out. One of them (A) slows down when passing through liquid, and speeds up when passing through solid. The other (B) completely stops when passing through liquid. When scientists measured the waves, they found that after a while, the A waves slow down and the B waves stop. Then the A waves began to speed up again. This suggests that there is something solid inside the earth.

Answer 2

based on the gravitational forces and temperature imparted at the center of the earth, some mathematical calculations are done to see that the force of gravity is much more than enough to keep the iron and nickel solid

Answer 3

The orbital period of the moon tells us the total mass of Earth, and we can measure the size; so that gives us an average density. We know the density of iron and nickel and they seem to be about right.

There's probably a lot of gold down there, too; but the people who own all the gold, up here, don't want us to know that; it would make their gold worthless.

Answer 4

We use sonar to shoot a signal to through the earth. it bouncing back at different intervals so we know whats liquid and whats solid. Also, it helps explain thigns like magnetic field and all that

Answer 5

It is actually molten and we actually don't. We assume it is because of materials from other broken planets (meteorites), from the behavoir of the magnetic field of earth and the calculations of density for the various layers of the earth.

Answer 6

we don't, we "know" its an iron/nickel alloy but its just an educated guess:

Answer 7

I don't know.