Guest post by David Schilter, Senior Editor Nature Reviews ChemistryWe interact with ordinary matter all the time. It is the bed in which you wake up in the morning and the food that you eat for breakfast. It is the people we love and the pets we often love even more. It is us. Being fairly prominent stuff, ordinary matter is often referred to as ‘the matter that matters’ and without doubt deserves our attention. But we should not forget that it only makes up 5% of our Universe, the remainder of which is dark matter. Indeed, dark matter crosses paths with all of us but unless you’re a physicist it is unlikely to have crossed your mind. This prompted The Science Gallery London to present Dark Matter (free admission, June 6 – August 26), an exhibition that finally brings this ubiquitous yet elusive subject to the masses. “95% of the Universe is missing”, the Gallery asserts, so they commissioned collaborative works from teams of artists and scientists to show us what and where this mass–energy really is.
For laypersons, the thought of dark matter is more likely to cue spooky music than to evoke thoughts about baryons (or the lack thereof). Dark Matter depicts the eponymous concept in an approachable way by using everything from music and mirrors to maps and movies. To be sure, the exhibition is not only a feast for the mind but also for the senses, which is ironic because none of our five senses can detect dark matter (perhaps we really do need that sixth sense…). Although we can’t see dark matter, perhaps, like false-colour imaging, we can guess how it would look like if we could see it. Similarly, we can’t hear, touch, taste or smell dark matter, but what if we could?
The mystery associated with dark matter is not limited to laypersons. Among physicists, the subject remains controversial because much of our knowledge comes only from indirect observations that implicate the existence of matter beyond the ordinary. For example, the velocities, X-ray spectra and gravitational lensing from galactic bodies are explicable in terms of an ‘invisible’ mass. Our poor understanding of the spacetime-bending dark matter concept isn’t for lack of trying, and this exhibition highlights the sophisticated experiments carried out by great consortia seeking to fill our knowledge gap. The scale of these mammoth efforts is conveyed to us in HIGGS, In Search of the Anti-Motti, a video in which artist Gianni Motti does his best proton impersonation and circumnavigates the Large Hadron Collider. Walking 27 km in less than 6 hours isn’t bad, although a proton does do it a hundred millions times faster. Efforts to spectroscopically detect dark matter have been likened to tuning a radio in search of a station that might not even exist. In Dark Matter Radio, an installation with a circular array of audio speakers playing sounds at different frequencies, and as we walk around we experience strange interferences and beats that Aura Satz uses to depict this tuning.
Perhaps the simplest way to explain dark matter is in terms of something invisible, this being despite most visitors to Dark Matter knowing full well that there’s plenty of ordinary matter we can’t see either. Nevertheless, artists Carey Young, Nina Canell and Robin Watkins present us apparently empty vessels that, statistically speaking, contain a lot of dark matter (not being under vacuum, they also contain plenty of normal matter, but that’s not the point). Much like our knowledge of Earth’s geography evolved into what it is today (The Maps of Phantom Islands by Agnieszka Kurant is a must-see), our knowledge of dark matter will surely develop commensurate with our technologies. The artist Satz is frank in her admission that these developments are unlikely to come from a fertilization of breakthroughs in these artist–scientist collaborations. But if the only breakthrough these collaborations achieve is to take the most esoteric topic and pique the attention of the general public then that will be breakthrough enough.