New Scientist | Special | 27 Sept 2010
- Here we are, small beings on a small planet orbiting an unremarkable star in a really rather ordinary galaxy in an otherwise undistinguished part of an unimaginably vast universe.
Yet something about our existence feels, well, special. From the ructions of the early cosmos to the growing pains of our planet and life’s daring evolutionary leaps, not everything about how we got here seems obvious, or even likely.
Perhaps in other corners of the cosmos other sentient beings are also pondering the implausibility of their origins. Perhaps that very implausibility means we are alone with such questions. Either way, follow the trail as we visit 10 turning points in our history - the cosmic accidents that led to us.
(Credit: Detlev Van Ravenswaay/SPL)
- 13.75 bya: How we avoided the void
We wouldn't exist if our cosmic neighbourhood had been just a bit less dense than average during the tumultuous moments after the big bang.(Credit: Lawrence Berkeley/SPL)
- 13.75 bya: Tipping the antimatter balance
Why isn't the cosmos a sea of bland radiation? The triumph of matter suggests that the laws of physics are biased.(Credit: SDO/NASA)
- 4.6 bya: Sparking up our star
What does it take to make a solar system? Hydrogen, helium, interstellar dust – and a spark to set it on fire.(Credit: KeystoneUSA-ZUMA/Rex Features)
- 4.5 bya: Mars attacks
A colossal interplanetary collision doesn't sound like a good thing – but without it, things might have turned out very differently.(Credit: NASA/Corbis)
- 3.9 bya: Blasting the Earth into life
The solar system's "late heavy bombardment" blasted our planet – but might also have delivered our water, and created nurseries for life.(Credit: Dr Gopal Murti/SPL)
- 2 bya: One giant leap for a single cell
A freak event created the ancestor of all multicellular life on Earth. Without this unconventional genesis, we might never have become more than bacteria.(Credit: Yva Momatiuk & John Eastcott/FLPA)
- 635 mya: The age of heroic lichen
Early life had to ride an oxygen rollercoaster – until humble symbioses of algae and fungus put an end to boom and bust.(Credit: Joe Tucciarone/SPL)
- 65 mya: Killer asteroid with a silver lining
A 10-kilometre-wide rock did for the dinosaurs, but smashed open a window of opportunity for unimpressive little animals called mammals.(Credit: Paul Souders/Corbis)
- 6 mya: Brains or brawn – which was best?
When the going got tough in prehistoric East Africa, some of humanity's closest relatives went for bigger jaws, rather than bigger brains. Big mistake.(Credit: Janek Skarzynski/AFP/Getty)
- 70 kya: Inventing language, the easy way
Fresh pastures meant a cosier life for early humans – if they hadn't, we would never have loosened up enough to learn to speak.(Credit: Prakash Singh/AFP/Getty)
- No particular time: The certainty of chance
Tiny changes at the beginning make big differences in the end. That's why our existence is perilously perched on a great pyramid of trivia.