A big rip, crunch & bang.

Life on earth has been going on for about three-and-a-half billion years. John Gribbin offers fresh and important insights into how life may have been seeded from space with organic molecules carried on cometary dust.
Astronomers have good reason to believe that the universe is about 13.7 billion years old. The Hubble space telescope has captured images of galaxies that formed just a billion years after the Big Bang. But it is what happened immediately after the Big Bang that has captured the imagination of cosmologists.
Cosmologists think they know that a period of rapid expansion, known as inflation, occured in the first few fractions of an instant after the universe began. We are not talking microseconds here, but unimaginably tinier fractions of time. Take for example the first point after the Big Bang when the strong force of gravity becomes a distinct entity- 10-35 seconds after the birth of the universe. (This number has 34 zeros between the decimal point on the left and the first digit on the right). Quarks, the family of fundamental  subatomic particles, came into their own in about 10-10 seconds after the universe began. For the briefest moment they existed as a plasma- a cloud - but this free living phase ended at 10-4 secods.
It was at this point that the universe entered the era of baryons, the visible matter that comprises the galaxies, stars and planets of today. Everything we see around us- including our own bodies- is composed of baryonic matter.
It is almost impossible to conceptualise these minute timescales.
The era of inflation that led to the establishment of gravity was as remote from the era of quark plasma as we ourselves are from the era of quark plasma- but of course in the other direction.
Cosmologists think they know that quantum fluctuations affected matter during this critical periodof inflation. these fluctuations seeded the process that ultimately led to the creation of a “clumpy” universe of stars, galaxies, planets and life. This belief forms one of the central tenets of the New Standard Cosmology, whichexplains how the universe evolved.
About 80 per cent of the universe does not exist as visible, baryonic matter, but something invisible and mysterious so called cold dark matter. Experiments are on to trap the ghostly sub-atomic particles that are thought tocomprise this dark matter. they have never been detected because  they pass straight through ordinary matter.
There is the weird hidden power called dark energy, which was revealed only a few years ago when astronomers realised that  something was accelerating the rate of the universe's expansion. it is believed that dark energy holds the universe together today, but, paradoxically, it seems that if the acceleration of the expansion continues, then it will also be responsible for blowing it apart- a Big Rip as opposed to the Big Crunch of a universe that implodes in on itself.
Cosmologists describe the universe as “flat”, meaning that it is balanced on a knife-edge between runaway expansion and precipitate collapse. They can explain our presence by the anthropic principle of cosmology, which simply states that we find ourselves living in a universe uniquely designed for life because we wouldn't be able to live in any other kind of universe.
Life on earth has been going for about three and a half billion years. Life may have been seeded from space with organic molecules carried on cometary dust. The vital elements of Carbon, Nitrogen and Phosphorus were forged in the nuclear furnaces of the stars, but more complicated organic molecules essential for life are known to be synthesised in interstellar clouds. 











































































 

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