Why oxygen existed before the atmosphere became oxygen-rich

Oxygen existed before oxygen-rich air

The first oxygen made on Earth did not simply collect in the atmosphere. Other gases and minerals reacted with it and used it up. Oxygen began building in the air only after production became greater than these chemical sinks.

A thin clay layer held unusual iridium

Up To 160× Background

A thin layer of clay in Italy contained up to 160 times the usual amount of iridium. Because iridium is rare on Earth but common in asteroids, researchers proposed that a vaporized impactor spread it around the planet before they identified the crater.

A theremin is played without touch

A theremin’s antennas sense how close the player’s hands are. The player’s hand movements control the instrument’s pitch and volume without physical contact.

Why oxygen existed before the atmosphere became oxygen-rich

Oxygen existed before oxygen-rich air

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