[awb]

> An upcoming NASA mission could find that there are more rogue planets — planets that float in space without orbiting a sun — than there are stars in the Milky Way, a new study theorizes.

I don't think we've detected a single rogue planet, so this theory would seem novel to me.

[ericbarrett]

There's at least one candidate: https://en.wikipedia.org/wiki/CFBDSIR_2149%E2%88%920403

(edit) Linked from the same article, a confirmed rogue planet: https://en.wikipedia.org/wiki/PSO_J318.5%E2%88%9222

[TheGallopedHigh]

It’s difficult because they generally do not radiate EM waves or specifically visible light.