Stripping Down Science by Chris Smith, Dr Christorpher Smith Read Free Book Online

shockwave is thought to have squeezed the gas together, causing it to begin to collapse under its own gravity, triggering the formation of a central ‘proto-star’. This would have been surrounded by a protoplanetary soup of spinning material from which the planets we see today would slowly have emerged as gravity glued the debris together.

    A nice theory, but a recent scientific discovery has shown that it’s a myth. If this model of earth’s birth were true, then remnants from the early solar system, such as ancient meteorites, ought to contain the signature of radioactive iron compounds known as iron-60, which would have been blasted from the innards of the star that exploded. But when Copenhagen University researcher Martin Bizzarro and his colleagues 23 went looking for this iron-60 (in the form of its radioactive breakdown product, nickel-60), they couldn’t find any. In fact, younger meteorites, formed after the solar system had come into existence, contained more iron-60 than the older ones. This totally turned the supernova theory on its head, because the story told by the meteorites suggested that a nearby star had indeed blown up back in history, but it happened after the solar system had already formed.
    So what did spark us into existence? Luckily, there was another chemical clue lurking inside the samples that the team analysed. Both the young and old meteorites contained another element, aluminium-26, and this can only mean one thing:that a super-massive star, at least 30 times the size of our own sun and with a lifetime of just a few million years, must have existed in our cosmic backyard during the time when the solar system was forming.
    Stars on this scale burn off their fuel very fast and produce a powerful solar wind laden with material from their surface layers, which includes aluminium-26 but not iron-60. ‘This rules out the supernova trigger,’ says Bizzarro. Instead, he thinks the wind from this giant star probably buffeted the ball of gas that became us into forming the solar system, adding aluminium-26 to the mixture as it went. A few million years later, the star blew itself to pieces, showering the young solar system with iron-60 from its core, thus explaining why the younger meteorites had the hallmark of iron-60 but the older ones didn’t.
    It looks as if we may have to rewrite the history of how the solar system came to be and on the basis of these findings, we may well have had gentler origins than space scientists first thought.

Nitrous oxide (formula N 2 O) is a volatile gas discovered by the English clergyman and scientist Joseph Priestley in 1793. (Priestley was certainly a bit of a gas man, because he also discovered oxygen, carbon monoxide, carbon dioxide, ammonia and sulphur dioxide.) Priestley made his nitrous oxide by heating ammonium nitrate in the presence of iron filings, and then passing the nitric oxide (NO) that came off through water: 2NO + H 2 O + FeN 2 O + Fe(OH) 2 .
    Humphry Davy, from the Pneumatic Institute in Bristol, England, then began to experiment with the physiological properties of the gas, and visitors to the institute were given nitrous oxide to breathe. Their reactions, and his own experiments, led Davy to coin the term ‘laughing gas’, and he also noticed that the gas had anaesthetic properties. ‘As nitrous oxide in its extensive operation appears capable of destroying physical pain, it may probably be used with advantage during surgical operations in which no great effusion of blood takes place.’

    However, for 40 years or so after Davy made this observation, most N 2 O was used for recreational purposes, including at public shows and carnivals where members of the public would pay a small price to inhale a minute’s worth of the gas. It wasn’t until the mid-1800s that doctors and dentists began to re-explore its painkilling potential.
    As is usually the case with a medical breakthrough, it took an