Did dinosaur-killing asteroid deliver a cancer cure to Earth?

Michael Irving, New Atlas | A rare metal brought to Earth by asteroids has been found to be an effective cancer killer.

Over 65 million years ago, an asteroid some 10 km (6 mi) wide crashed into the Earth and wiped out the dinosaurs.

Strangely, the legacy of this huge space rock could include a treatment for cancer after scientists from the UK and China demonstrated that iridium – a rare metal delivered to Earth by the asteroid – can be enlisted to kill cancer without harming healthy cells.

Laser-based techniques are emerging as viable treatments for cancer, targeting tumors far more precisely than the shotgun blast of radiation and chemotherapy.

In that vein, researchers from the University of Warwick in the UK and Sun Yat-Sen University in China have found that laser light can turn iridium into an effective cancer killer.

First, the team created a compound of iridium and organic materials and then introduced it into a lung cancer tumor grown in the lab.

When red laser light is shone onto it through the skin, the compound is activated, converting the oxygen in the tumor into singlet oxygen, a poisonous form of the element that effectively kills the cancer cells from the inside.

With cancer becoming resistant to certain treatments, it’s crucial to find new methods such as this.

The research was published in the journal Angewandte Chemie.

Source: University of Warwick. Read the full story at New Atlas

Iridium

From Wikipedia, the free encyclopedia

Iridium is found in meteorites in much higher abundance than in the Earth’s crust.

Iridium is a chemical element with symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, iridium is the second-densest element (after osmium). It is also the most corrosion-resistant metal, even at temperatures as high as 2000 °C.

Although only certain molten salts and halogens are corrosive to solid iridium, finely divided iridium dust is much more reactive and can be flammable.

Iridium was discovered in 1803 among insoluble impurities in natural platinum. Smithson Tennant, the primary discoverer, named iridium for the Greek goddess Iris, personification of the rainbow, because of the striking and diverse colors of its salts. (Content continues below … )

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Iridium is one of the rarest elements in Earth’s crust, with annual production and consumption of only three tonnes. 191Ir and 193Ir are the only two naturally occurring isotopes of iridium, as well as the only stable isotopes; the latter is the more abundant of the two.

The most important iridium compounds in use are the salts and acids it forms with chlorine, though iridium also forms a number of organometallic compounds used in industrial catalysis, and in research.

Iridium metal is employed when high corrosion resistance at high temperatures is needed, as in high-performance spark plugs, crucibles for recrystallization of semiconductors at high temperatures, and electrodes for the production of chlorine in the chloralkali process. Iridium radioisotopes are used in some radioisotope thermoelectric generators.

Iridium is found in meteorites in much higher abundance than in the Earth’s crust.

For this reason, the unusually high abundance of iridium in the clay layer at the Cretaceous–Paleogene boundary gave rise to the Alvarez hypothesis that the impact of a massive extraterrestrial object caused the extinction of dinosaurs and many other species 66 million years ago. Similarly, an iridium anomaly in core samples from the Pacific Ocean suggested the Eltanin impact of about 2.5 million years ago.

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.