Photographer Yuri Beletsky recently captured this stunning photo of comet C/2014 Q1 (Pan-Starrs) which is currently visible in the Southern Hemisphere.
The photo — a High Dynamic Range (HDR) composite — was taken from a valley in northern Chile late last week. Beletsky had to climb a hill to get the exact shot because the region is surrounded by mountains. I’d say he nailed it.
Comet C/2014 Q1 was discovered last year by astronomers working at the Panoramic Survey Telescope and Rapid Response System, hence the suffix “Pan-Starrs.”
The Moon in this photo is a thin crescent, which is why its lower portion appears so bright; the long exposure allows its darkened features to be seen.
Phil Plait, author of the Bad Astronomy Blog, explains the comet’s unique features:
The comet is sporting two very different tails! Pointing straight up is the ion tail, made of gas that sublimated away from ice in the comet and which was subsequently ionized by the Sun’s ultraviolet light. Ionized gas is missing one or more electrons, giving the atoms or molecules a positive charge. The Sun’s solar wind blowing past the comet carries its own magnetic field, which sweeps up the ions and carries them away. The solar wind is typically blowing at several hundred kilometers per second, far faster than the comet, so the ion tail points directly away from the Sun.
In the meantime, as the ice holding the comet together turns to gas, it also loosens dust in the comet. This leaves the solid nucleus, and gets hit by sunlight. This gives the dust particles a little bit of energy, changing their orbits much more gently than the ions. The dust tail curves away from the comet, leaving in very nearly but not quite the same orbit.
Much more here.