International Dark Matter Day

Abell S1063, a galaxy cluster, was observed by the NASA/ESA Hubble Space Telescope as part of the Frontier Fields programme. The huge mass of the cluster acts as a cosmic magnifying glass and enlarges even more distant galaxies, so they become bright enough for Hubble to see.

On October 31, 2017, the world will celebrate the international hunt for dark matter. Armagh Observatory and Planetarium will be having a special showing of the “Phantom of the Universe” at 2pm, a Full Dome show which discusses our understanding (or lack thereof) Dark Matter, and the search to find out what it might be.

Less than 5 percent of the total mass and energy in the universe is the stuff we know about: like stars, planets, galaxies, and gases.

Dark matter makes up about 85 percent of the total mass of the universe, and about a quarter (26.8 percent) of the universe’s total mass and energy. Almost 70 percent (68.3 percent) of the universe’s mass and energy is composed of dark energy, another big mystery to scientists that is causing the accelerated expansion of the universe.

Dark matter allows galaxies to spin at a faster-than-expected rate without unraveling and flinging matter off into surrounding space. It could be undiscovered particles swirling around our cosmos or a huge glitch in our understanding of gravity and the fundamental laws of physics. We simply do not know. A host of innovative experiments are hunting for the source of dark matter using mile-deep detectors, powerful particle beams, and even space-based telescopes.

Dark matter has so far only been detected through its gravity-based effects in space. At 85% of the mass of the Universe that’s a BIG part of the universe that we don’t know much about. We’re not sure if dark matter is made up of undiscovered particles, or if it can be explained by tweaking the known laws of physics. Solving the mystery of dark matter a key pursuit in physics. Doing so will surely teach us much about the history and structure of our universe.

A recent observation by the Hubble Space Telescope  has shown that the brightest galaxies within galaxy clusters “wobble” relative to the cluster’s centre of mass. This unexpected result is inconsistent with predictions made by the current standard model of dark matter. We don’t yet understand what this means, it may provide insights into the nature of dark matter, perhaps even indicating that new physics is at work?


Michael Burton, Director of Armagh Observatory and Planetarium

Professor Michael Burton,
Director of Armagh Observatory and Planetarium