Iridium Question -- Why is Iridium plentiful in space rocks but scarce on Earth?

[Sanborn Chase]

Why is iridium plentiful in space rocks but scarce on earth?

 

[jim mcnamara]

From https://en.wikipedia.org/wiki/Iridium

It is thought that the total amount of iridium in the planet Earth is much higher than that observed in crustal rocks, but as with other platinum-group metals, the high density and tendency of iridium to bond with iron caused most iridium to descend below the crust when the planet was young and still molten.

So, the "missing" Iridium took a one way trip into Earth's core.

 

[AlexTheParticle]

There are a few reasons for this. First, it's important to understand that iridium is a rare element in general, so it's not surprising that it's scarce on Earth. However, it is more abundant in space rocks because these rocks come from the outer reaches of our solar system where the conditions are different than on Earth.

One reason for this is that iridium is thought to have been brought to Earth by meteorites and other space debris. These objects often contain a higher concentration of iridium compared to the Earth's crust, which is why it is more plentiful in space rocks. Additionally, the Earth's crust has undergone extensive geological processes over billions of years, which has led to the depletion of iridium in the Earth's surface.

Another factor to consider is that iridium is a heavy element, which means it tends to sink towards the Earth's core during the planet's formation. This is why it is more abundant in the Earth's core than in the crust. However, space rocks are not subject to the same geological processes and therefore, the iridium is more evenly distributed throughout them.

Overall, it's a combination of these factors that make iridium more plentiful in space rocks compared to on Earth. It's important to note that while iridium may be scarce on Earth, it is still an incredibly valuable element and has many important industrial and technological applications.