Showing posts with label molten. Show all posts
Showing posts with label molten. Show all posts

Earth's Oldest particle Found in Western Australia - a Zircon Crystal

Everyone knows that Australia is old. Just how old has been defined by science - A zircon crystal on a Western Australian sheep station is the oldest piece of planet Earth. It is 4.4 billion years old.

Tests were done to determine the crystal's age. The rate of decay of uranium against the constant lead showed how old it was. This was confirmed by atom-probe tomography where the mass of lead atoms is measured.

The zircon particle was created on the Earth's crust soon after the planet formed. And the Earth was not a violent place until much later. Water was already present and there is a high probability that life began at this time. The Hadean eon as this period is called in now a misnomer because it means Hadean the god of hell.

Proof of life is unlikely. Science is not advanced enough yet to fully examine this period. Very little can be identified as originating in this period of the Earth's development.
Science by Ty Buchanan
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
     Australian Blog                         
ALL BLOG ARTICLES· ──► (BLOG HOME PAGE)

Asteroids Can Have Magnetic Fields

It has been found that asteroids can have magnetic fields. This was quite a surprise. Planets have magnetic fields due to a moving molten metal core. Mercury has a very strong field. The reason for this is not yet known.

Vesta is a large asteroid with a diameter of 525 kilometer. It was first identified in 1807 by Heinrich Wilheim Olbers. It is the most easily seen asteroid from Earth. Smaller asteroids hit Vesta and some of the debris falls to Earth. The fallen "rocks" can be linked to Vesta because they have the same spectral color match.

Vesta is unusual for an asteroid as it once had a crust, mantle and molten metal core. The orbiting dawn spacecraft/satellite confirms this. It is now frozen and no longer active. A meteor named Alan Hills A81001 composed of Vestan crust fell to Earth in the Arctic. When it was analysed it was found to have a weak magnetic field.  The original crust gained  a magnetic field when it cooled 3.7 billion years ago. An impact a billion years later hit the frozen crust. This melted and refroze some crust which resulted in magnetism being transferred, imprinted, on rock which became the Alan Hills meteor.
. . . . . . . . . . . . . . . . . . . .
Science
TwitThis