Dark matter and its part in the evolution of the Universe is revealed by new data collected by the Hubble Space Telescope.
The light and the dark: a HST image of galaxies with the distribution of dark matter superimposed (Image credit: NASA, ESA, P. Simon (University of Bonn) and T. Schrabback (Leiden Observatory))
This image could be taken for a lurid TV special effect (the Lights of Zetar perhaps?) but it may actually represent proof of that elusive and mysterious entity, dark energy.
A combination of 575 images from the Hubble Space Telescope and data from ground-based telescopes, the image contains 446 000 galaxies. The most distant galaxies’ shapes appear distorted but this is an illusion. The galaxies are normal, but the light from them has been warped as it traversed billions of light years of space subtly bent by the gravitational pull of intervening matter. Quantifying this warping, known as “weak gravitational lensing” enables scientists to calculate how much matter exists in the greater Universe and how it is distributed. This matter includes not only the kind of stuff which makes up stars, planets and you and me but also the enigmatic dark matter which stops galaxies from flying into pieces.
The results help confirm that the Universe is not only expanding but the rate of expansion is increasing. This caused by dark energy, a mysterious ‘something’ which is undetectably weak in the laboratory, but over huge periods of time is pushing the galaxies apart. The Universe is getting ever bigger, ever faster.
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