In 2004, the European Space Agency launched the space probe Rosetta to study asteroids and comets. In November 2014, its lander Philae touched down on comet 67P/Churyumov–Gerasimenko. The probe also carried a mass spectrometer ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis). This made “the most surprising discovery” about the comet to date, according to Principal Investigator Kathrin Altwegg of the University of Bern, Switzerland.
There was a lot of free oxygen gas (O2) in the comet coma (or atmosphere)—almost 4% as much as the most abundant gas, water vapour.2 In fact, it was consistently high over seven months from September 2014 to March 2015.
For the last six decades, it has been a widely believed myth that life on Earth evolved in a primordial soup.5 The basic chemicals in the soup were allegedly generated by UV radiation and lightning in a primordial atmosphere unlike the present one. It was allegedly ‘reducing’, meaning it contained hydrogen-rich compounds like methane (CH4) and ammonia (NH3) and lacked oxygen. Our current ‘oxidizing’ atmosphere would prohibit all this, because oxygen would destroy the so-called building blocks, and indeed prevent their formation in the first place. . . .