Ice Giant Neptune's Fiery Glow
Let's face it — we just don't get to see enough of Neptune these days. For good reason, I suppose, as it's pretty far away — say, 2.7 billion miles away, or 30 times the distance from here to the sun — and it hasn't been visited by a spacecraft since Voyager 2 passed by back in the summer of '89.
It's not visible with the naked eye from Earth, and even with a telescope it can be tricky to observe for the average backyard astronomer. But Neptune is very much a full-fledged and fascinating member of our solar system's family and was recently targeted by California Institute of Technology astronomer Mike Brown, who took some great shots of the distant world with the 10-meter (33-foot) telescope at Hawaii's Keck Observatory!
Normally only visible as a featureless blue speck in telescopes, the icy gas giant — along with its largest moon, Triton — glows bright red and orange in the infrared light of Brown's images.
Brown's intention was not merely to get pretty pictures of planets, though. The goal of the mission was to capture images of Triton, to learn more about the positioning of its methane, nitrogen and seasonal frosts, and this sort of research requires infrared imaging. Of course, Neptune proved to be quite photogenic itself in infrared.
"The big difference is doing the imaging in the infrared, where methane absorbs most of the photons," says Brown. "So the bright places are high clouds where the sunlight reflects off them before it has had a chance to pass through much of the atmosphere. Dark is clear atmosphere full of methane absorption."
"I just thought it was so spectacular that I should post it."
We're glad you did, Mike! It's incredible.
Neptune, now officially the outermost planet in our solar system, is the fourth-largest planet and boasts the highest wind speeds yet discovered — 1,250-mph winds scream around its frigid skies!
Its visible-light color comes from its atmospheric composition: Hydrogen and helium are invisible, but methane absorbs the red spectrum and so it appears blue. Like the other gas planets Neptune has a system of rings, although nowhere near as extravagant as Saturn's. It has 13 known moons, of which Triton is the largest.
Triton, with its retrograde orbit, is believed to be a captured Kuiper Belt object now in orbit around Neptune. Kuiper Belt objects — KBOs for short — are Mike Brown's specialty, as he is the astronomer most well-known for instigating the process that got Pluto "demoted" from the official planet list in August 2006.