Platinum, iridium and the rest are expensive precisely because they are rare.

正因为稀有，、等矿物才价格不菲。

If I run the hydrazine over an iridium catalyst, it'll separate into N2 and H2.

假如我用催化剂分解联氨，它将分解成氮气和氢气。

I'm going to delete " cretaceous, " I'm going to delete " Cenozoic" and I'm going to delete " iridium."

我要删除“白垩纪”、“新生代”、“”。

The metre was the distance between two scratches on a bar composed of a special alloy of platinum and iridium.

1米是指一根特殊合金杆两端划痕间的距离。

Iridium...What do they need the iridium for? -It's a stabilising agent.

...他们要干什么？-用来做稳定剂。

Yeah, iridium. It's found in meteorites. It forms anti-protons.

是的，金属。这种西是从陨石中发现的。可以形成反质子。

Iridium is an element that’s rare on Earth, but very common in asteroids and comets.

是地球上稀有的元素， 但在小行星和彗星中却很常见。

The earth has Iridium in it, but because it is a heavy metal, most of it settles towards the center of the planet.

地球也有，但因为它是重金属，多数都沉降到行星的中心。

It's about 65 million years old and contains a lot of iridium, an element that's usually rare on Earth's surface.

它大约有 6500 万的历史，含有大量的，这种元素在地球表面通常很稀有。

Iraq reported the theft of up to 10 grams of iridium isotope used to treat cancer to the International Atomic Energy Agency late last year.

伊拉克报道底报道国际原子能机构用来治疗癌症的同位素丢失了10克。

There must have been a long time, between the impact below the core and the arrival of the Iridium at the top.

所以岩芯下的碰撞坑和顶部的元素层必然间隔了很长一段时间。

A hunk of platinum and iridium known as the International Prototype Kilogram or IPK. The IPK isn't just how much a kilogram weighs.

一大块和，为国际原型千克或 IPK。 IPK 不仅仅是一公斤的重量。

Indeed, the discovery of a layer of iridium-rich rock (iridium being one of platinum's relatives) was the first sign geologists found of the asteroid impact that is believed to have killed the dinosaurs.

实际上，地质学家们提出小行星曾撞击地球的第一个证据就是发现了富含的岩层（是的同族元素之一）。人们认为恐龙就是因小行星撞击地球而灭绝的。

Among these is the element iridium, which is a thousand times more abundant in space than in the Earth's crust (because, it is thought, most of the iridium on Earth sank to the core when the planet was young).

其中有元素。这种元素在太空里要比在地壳里丰富100倍(据认为，这是因为大部分在地球形成之初已经沉入地心)。

And um, anything else that looks like it may not appear, " iridium" is an element, probably not going to get that on the test, so I am going to delete it, that's I don't want to waste my time studying that.

其他任何看起来可能不会出现的西，“”是一种元素，可能不会出现在考试中，所以我要删除它，因为我不想浪费时间研究它。