ASTRONOMERS in the US have mapped a cluster of invisible galaxies for the
first time. They spotted the cluster by analysing the effect its gravity had on
the light from more distant galaxies. The discovery opens a new window on the
Universe, because a large part of its mass may be “dark matter”.
Last year, a team of European astronomers caught a glimpse of a dark galaxy
as it distorted light from the more distant bright ones they were imaging. But
astronomers have never been able to confirm such sightings or work out what the
galaxies were like. “It was…
