by Jennifer Coote


The familiar structures which apparently make up our universe, from atoms to galaxies, say current physicists, take up barely 4% of the energy and matter around. The rest, called dark energy, is making the universe expand at an accelerating rate. Dark matter makes up about a quarter of this, but its character is unknown. Precise computations form the evidence for this hypothesis, formulated from observations of the constraint on the way the dark matter is distributed in the universe. Evidence of this constraint arises from observations of cosmic microwave background radiation left over from the Big Bang, and of galaxy rotation. Gravity and gravitational lensing (bending light) show that this dark matter not only exists, but that its composition differs from that of visible matter, being more exotic, and slow moving. Very recent scientific simulations suggest that this structure is denser and richer than previously thought. Dark mini-galaxies may abound. The Economist, 12 April 03, pp 70-71. (continue…)


View PDF