‘Illuminating the Dark Universe’

‘Portraits of the earliest universe and the lacy pattern of galaxies in today's sky confirm that the universe is made up largely of mysterious dark energy and dark matter. They also give the universe a firm age and a precise speed of expansion.’

•Ordinary matter takes up ~5% of total mass; 95% of matter are dark matter

•matter accounts for 0.3 of total energy; 0.7 are ‘dark energy’ (vacuum energy)

•the universe is flat (k = 0)

•If there were no dark matter:

•Galaxies 星系would be much smaller: most stars would have escaped

•Galaxy clusters 星系團could not have formed

•Hot gas surrounding most galaxy clusters would have escaped

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Dark Matter – need them for the structures in the universe! Numerous proposals for what they are, but mostly particles yet undiscovered!!!!!!