Relative to the oldest rocks that have been found on the moon, the oldest rocks found on the earth are?

Question

A. younger
B. very much older
C. somewhat older
D. about the same age

Answer 1

The answer is A. Younger

We have found rocks on the Moon that date older than rocks found on the Earth, by using radiometric dating of rocks. In radiometric dating, scientists measure the amounts of different isotopes of certain elements in a rock sample. Since radioactive isotopes are known to decay at a certain constant rate, the amounts remaining in the rock will tell how old it is. For igneous rocks this is the time when it solidified from molten magma.

The Earth is calculated to be 4.5 billion years old. The oldest rocks ever found on Earth are actually about 3.8 billion years old. Most rock found on the Earth's surface is much younger because Earth's crust is "recycled" by plate tectonics. The radioactive "clock" in the rock is reset when it is melted or heated to high temperature.

So if the oldest rocks ever found on Earth are 3.8 billion years old, how do we know that the Earth is older than that?

Because we have some rocks that are not from the Earth!

Moon rocks and meteorites are older than any Earth rocks we know of. The Moon rocks collected on the Apollo missions and most meteorites that have hit the Earth are about 4.5 billion years old. The Moon doesn't have plate tectonics, so its crust is not recycled. The rock now on the Moon's surface was formed when the Moon was formed. Meteorites also would have been made when the solar system was formed, and of course the Earth would have been made at the same time as the rest of the solar system.

There you go ! Have fun!

Answer 2

Actually, earth rocks are younger. Between tectonic plate movement and erosion, the rocks from the earth's earliest years no longer exist. On the moon, the oldest rocks date clear back to 4.5 billion years ago, when the earth and moon were formed.

The oldest known earth rocks are about four billion years old.

Answer 3

The same - because the moon was once part of the earth. It is a chunk of the planet that was knocked loose by an asteroid.

Answer 4

A. younger
B. very much older
C. somewhat older
D. about the same age

Answer 5

d the same
3.9 billion years