The comet as seen by the largest single telescope on Earth, the Arecibo.
The deep impact camera.
"This morning, NASA's Deep Impact (EPOXI) probe flew past Comet Hartley 2 only 435 miles from the comet's active nucleus. The spacecraft has since turned its high-gain antenna toward Earth and data are being transmitted to mission control at JPL. Even without processing, the first raw images are spectacular.
At a press conference on Thursday afternoon, mission scientists discussed their first impressions. The comet has a dumbbell shape, they noted, with rough ends and a smooth middle. Jets come from rough terrain and seem to be correlated with specific topographic features. The middle is covered with some kind of fine dusty material that has collected in a topographic low point.
The images reveal a comet bristling with gaseous jets--even on the comet's nightside where volatile ices are temporarily protected from solar heating. Distinct lines of jets trace the comet's day-night terminator. Researchers again expressed their amazement at Comet Hartley 2's hyperactivity."
As usual, the Planetary Society Blog is the best place to go for these kinds of events. Here are some early images from Emily:
Now it is very premature to begin speculating on the nature of this comet. But to my eye, it looks almost as if the two ends are large rubble piles or solid objects, and the center is mostly a fine powder or pile of smaller particles. Almost as if two objects have a central column of dust between them. Is this possible? Wouldn't there be some kind of gravitational limbo between two large masses like that?