But Nix and Hydra are about 26 and 34 miles long, respectively. They're also much further away from Pluto than Charon is, so the New Horizons spacecraft could only get a distant glimpse at them as it sped by into the Kuiper Belt.
But these new photos are more than just blobs: Scientists are already using them to try to make conclusions about the tiny moons.
(Side note: This kind of on-the-fly planetary science -- based on data we'll receive bit by bit for the next 16 months -- is a rare opportunity to see scientists make immediate conjectures and talk about them publicly. So enjoy it but also maybe keep in mind that the next batch of photos could completely contradict the assumptions made previously.)
Hydra, previously described on this very blog as being shaped like a "space spud," now resembles the state of Michigan -- at least according to NASA scientists. It's estimated to be 34 miles long and 25 miles wide, with at least a couple craters and some color differences that hint at variations in the composition of Hydra's surface.
The itty-bitty Nix, jelly-belly of a moon that it is, looks to be about 26 miles long and 22 miles wide. As you may have noticed, it's kind of red. That's unexpected!
“Additional compositional data has already been taken of Nix, but is not yet downlinked," mission scientist Carly Howett said in a statement. "It will tell us why this region is redder than its surroundings. This observation is so tantalizing, I’m finding it hard to be patient for more Nix data to be downlinked.”
The team already thinks it can make out a bulls-eye pattern around the gray moon's red spot, so its guess is that it's some kind of impact crater.
And don't forget Pluto's even more obscure moons: Humankind should see its first photos of Styx and Kerberos sometime in October.