We do, however, have bigger brains than most animals – not the biggest, but packed with three times as many neurons as a gorilla (86bn to be exact). Just looking at your DNA won’t tell you – the human genome is 99% identical to a chimpanzee’s and, for that matter, 50% to a banana’s. Some say life began in hot pools near volcanoes, others that it was kick-started by meteorites hitting the sea. But how did the basic chemicals present on early Earth spontaneously arrange themselves into something resembling life? How did we get DNA? What did the first cells look like? More than half a century after the chemist Stanley Miller proposed his “primordial soup” theory, we still can’t agree about what happened. We humans are linked by evolution to those early biological molecules.
A few simple chemicals got together and made biology – the first molecules capable of replicating themselves appeared. Astronomers are closing in on the true identities of these unseen interlopers.įour billion years ago, something started stirring in the primordial soup.
Unveiled in 1998, the latter is pushing the universe’s expansion to ever greater speeds. The former, first discovered in 1933, acts as an invisible glue, binding galaxies and galaxy clusters together. Over the past 80 years it has become clear that the substantial remainder is comprised of two shadowy entities – dark matter and dark energy.
Atoms, which form everything we see around us, only account for a measly 5%. Astronomers face an embarrassing conundrum: they don’t know what 95% of the universe is made of.