Starship Asterisk*

Boomer12k wrote:Interesting perspective.

Another one was a picture of a small blob with another smaller blob very close to it, and stars in the background. It was from the Messenger spacecraft about to orbit Mercury at the time, I think, and the picture was of Earth and the Moon...

:---[===] *

zbvhs wrote:
The feathery structure has been seen before as I recall. What I find interesting is the two "jets" at extreme angles to the rest and the curly structure in the one second from the top. Any idea what might be causing these?

http://www.planetary.org/blogs/guest-blogs/2013/20130314-comet-panstarrs-stereo.html wrote:

Click to play embedded YouTube video.

Comet PANSTARRS from the other side of the Sun!
Posted By Karl Battams, 2013/03/14 05:21 CDT

<<What you might... notice in the PANSTARRS movie is that there’s actually more than one tail on this comet. In fact, there are at least three! The first one is the big dust tail I just spoke about, and by far the dominant feature of the comet. But if you watch the movie again we can see a short spikey tail pointing towards the lower-left of the images. This is very likely to be another dust tail, but one composed of very large and heavy pieces of cometary material that are not so easily influenced by the solar wind or radiation pressure. Instead, they’re big enough that they simply continue to follow the comet in its orbit, rather than being pushed outwards by other forces. Many of the higher-quality images taken from Earth also show this tail.

In addition to those two dust tails, on the right of the comet nucleus we see a thin third tail pointing radially away from the Sun. This is an “ion” or “gas” tail and is the result of the solar wind ionizing the neutral gas in the comet’s coma and releasing a stream of ions pointing directly away from the Sun. Interestingly, these ions can be highly affected by magnetic fields, and it just so happens that the solar outflow in general contains a very complicated and highly variable magnetic field. The result of this is that we frequently see twists and turns in the ion tail of comets, particularly in our STEREO images. Actually, though, PANSTARRS' ion tail is holding very steady. This might be a hint that it is composed of slightly more “exotic” ions than we typically see; perhaps Fe+, but we are going to need to turn to our computer models to figure that out!>>

JohnD wrote: Some sort of indexing glitch?
John

yasgur wrote:Very cool shot. What are the little double spots that look like quotation marks. Some kind of artifacting or are background stars being doubled?

starstruck wrote:Note to the editors: the "discuss" link on the APOD page points towards yesterday's discussion.