241 Pizza

5. LIFE

Are you more than just a bag of chemicals?

Are you more than the sum of the inanimate chemicals that make up your body? What turns a living tree into a lifeless piece of wood? No one knows. Researchers have even given up trying to define what life is. But they are still trying to understand it – by making it from scratch. In labs across the world, people are taking the raw materials of living things and trying to put them together in a way that makes them come alive. In an effort to resolve the anomalous nature of life, the idea of scientists playing God has taken a whole new turn. Times Archive: Dr Edmund Leach on when scientists play God, 1968

6. METHANE FROM MARTIANS

NASA scientists found evidence for life on Mars. Then they changed their minds

On July 20, 1976, the Viking landers scooped up some Martian soil and mixed it with radioactive nutrients. The mission's scientists all agreed that if radioactive methane was released from the soil, something must be eating the nutrients – and there must be life on Mars. The experiment gave a positive result, but NASA denied an official detection of Martian life. Today, there is even more evidence that something is creating methane on Mars. Is it life? The Viking experiment suggests it was. Martin Rees, England’s astronomer royal, calls the search for extraterrestrial life the most important scientific endeavour of our time. But have we already found it? Times Archive: Spacecraft evidence suggests life on Mars was possible, 1976

7. THE WOW! SIGNAL

Has ET already been in touch?

It was an electromagnetic pulse that came from the direction of the Sagittarius constellation. It lasted 37 seconds and had exactly the characteristics predicted for an alien signal. Maybe that’s why, on 15 August 1977 it caused astronomer Jerry Ehman to scrawl "Wow!" on the printout from Big Ear, Ohio State University's radio telescope in Delaware. The nearest star in that direction is 220 light years away. If that really is where is came from, it would have had to be a pretty powerful astronomical event - or an advanced alien civilisation using an astonishingly large and powerful transmitter. More than 30 years later, its origin remains a mystery. Times Archive: ET, The Extra Terrestrial, The Times review 1982

8. A GIANT VIRUS

It’s a freak that could rewrite the story of life

Mimivirus is sitting in a freezer in Marseille. Around thirty times bigger than the rhinovirus that gives you a common cold, it is by far the biggest virus known to science. But this virus’s biggest impact won’t be on the healthcare systems of the globe. It will be, most likely, on the history of life on Earth. Mimivirus doesn’t fit with the established story of how life on Earth got going. Mimi has a genome that, in parts, looks like yours. Mimivirus seems to be part of the story of life on Earth. It may even make us rewrite it.

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