Starts With A Bang

Strange but true: dark matter grows hair around stars and planets (Synopsis)

Image credit: Gary Prezeau, via

“Few enterprises of great labor or hazard would be undertaken if we had not the power of magnifying the advantages we expect from them.” -Samuel Johnson

Dark matter may make up 27% of the Universe’s energy density, compared to just 5% of normal (atomic) matter, but in our Solar System, it’s notoriously sparse. In particular, there’s just a nanogram’s worth per cubic kilometer, which makes the fact that we’ve never directly detected it seem inevitable.

Image credit: J. Cooley, Phys.Dark Univ. 4 (2014) 92-97, via

But recent work has demonstrated that Earth and all the planets leave a ‘wake’ of dark matter where the density is enhanced by a billion times or more. Time to go put those dark matter detectors where they belong: in the path of these dark matter hairs.

Image credit: NASA/JPL-Caltech.

Go find out the full story of how this happens, and what we should do about it!