Using DNA to Detect Dark Matter

Particle physicists and biologists unite to answer one of the most puzzling questions of the universe: Does dark matter exist?

Jul 5, 2012
Cristina Luiggi

A Hubble Space Telescope image of the Sombrero galaxy, M104 NASA

For decades, physicists have been puzzled by the mystery of the universe’s missing mass. Known as dark matter, this mysterious stuff is thought to be at least five times more abundant than normal matter, and its gravitational pull is believed to shape galaxies and the visible universe itself. However, because dark matter particles don’t absorb or emit light, or even interact with normal matter, definitively proving its existence has been an astronomical challenge.

Enter genetics luminary George Church of Harvard University, who, along with dark matter expert at the University of Michigan in Ann Arbor, Katherine Freese, and others, believes he can use DNA to answer this Nobel-Prize-worthy question.

This motley team of biologists and physicists are currently working on building a dark matter detector made up of many single DNA strands—as long as 10,000 bases each—hanging from thin sheets of gold. Each of these strands will have a unique sequence, and its exact position in the gold sheet will be known. The idea is that every now and then, one of these dark matter particles will slam into the gold sheet, releasing a gold atom that will then plough through the hanging forest of DNA strands. The severed DNA sequences are then collected in a tray and used to recreate the path of the gold atom with nanometer resolution.

The DNA dark matter detector, if built, will not only greatly surpass the resolution of current dark matter detectors, but it will provide information about the directionality of dark matter particles, Technology Review reports. The latter point will be crucial in positively identifying dark matter particles because, depending on the earth’s position around the sun, the planet is traveling with or against a current of dark matter particles. Therefore, knowing the direction in which the particles are hitting the detector will help distinguish between dark matter particle collisions and those caused by unwanted normal radiation. (Hat tip to Wired Science.)