WISE image of Comet Siding Spring. Click for a larger version. Image credit: NASA/JPL-Caltech/UCLA

The WISE spacecraft has released the first of a group of handpicked images it has taken since it really got going in mid-January.

The particular image I have here is of Comet Siding Spring or more formally C/2007 Q3 was discovered in 2007 by observers at the Siding Spring Observatory in Australia.

The color might not be what you would normally expect, but this is actually very familiar to devotees of infrared images. The best way to explain it is to let NASA do it for me from the press release.

In this view, longer wavelengths of infrared light are red and shorter wavelengths are blue. The comet appears red because it is more than ten times colder than the surrounding stars, for example, the bright blue star in the foreground. Colder objects give off more of their light at longer wavelengths. An ice cube, for example, pours out a larger fraction of its light at longer infrared wavelengths than a cup of hot tea emits.

In this image, 3.4-micron light is colored blue; 4.6-micron light is green; 12-micron light is orange; and 22-micron light is red. It was taken on Jan. 10, 2010.

This particular comet is heading away from us at the moment after coming about 1.2 AU from Earth (1 AU = the average Sun to Earth distance), The tail of the comet is estimated at 10 million miles long.

There are other images available which you can see here.

I’ve already been asked why NASA isn’t releasing the images very quickly. I think probably the reason is out of necessity. If NASA were to release every image, for one thing they would be spending all their time doing it and for another you’d be pretty disappointed with most of them because they just wouldn’t show very much. I think the spacecraft can take an image about every 11 seconds and it will do this for six months and then start all over again. So to get any images for now is quite good and you can see why they have to pick and choose.

Stay tuned because this mission is going to get very exciting.  If you want to see the image above in its original context and with the full caption click here.