New Horizons' LORRI instrument took this dramatic image of Jupiter's volcanic moon Io just about 5 hours after the spacecraft's closest approach to the planet February 28. Io was 1.5 million miles (2.5 million kilometers) away.
Details as small as 7.4 miles (12 km) can be seen on Io. Prominent in the image is the enormous 180-mile-high (290 km) plume from the volcano Tvashtar, at 11 o'clock near Io's north pole. The Hubble Space Telescope first detected the plume 2 weeks ago; New Horizons caught a glimpse of it February 26.
Io's dayside was deliberately overexposed in this picture to image the faint plumes, and the long exposure also provided an excellent view of Io's night side, illuminated by Jupiter. No previous image by any spacecraft has shown these mysterious structures so clearly.
The image also shows the much smaller symmetrical fountain of the plume, about 40 miles (60 km) high, from the Prometheus volcano at 9 o'clock. The top of a third volcanic plume, from the volcano Masubi, erupts high enough to catch the setting Sun on the night side near the bottom of the image, appearing as an irregular bright patch against Io's Jupiter-lit surface. Several Everest-sized mountains are highlighted by the setting Sun along the terminator, the line between day and night.
This is the last of a handful of LORRI images that New Horizons is sending "home" during its busy encounter. Hundreds more, plus other data, are stored onboard. The rest of the images will be returned to Earth over the coming weeks as the spacecraft speeds along to Pluto.