Comet Siding Spring Meets the Red Planet

One of the benefits of having an amazingly keen-eyed space telescope like Hubble orbiting Earth is that you get great scenes like this one — Comet C2013 A1 Siding Spring passing by the planet Mars on October 19th. Hubble Space Telescope is actually so sensitive that scientists had to adjust the exposure to get the image. In addition, the scene is a dynamic one; that is, the comet and planet are moving with respect to each other, and a single exposure of the view was impossible to get without some blurring. So, the telescope took a series of images which were then composited together to get this interplanetary selfie. The image was taken using the Wide Field Camera 3. For more information, check out the Hubble press release page for the image.

Comet Siding Spring is getting closer to the Sun and will reach perihelion (the closest point in its orbit) on October 25th. After that, it will head back to the outer solar system on its lengthy orbit. The comet originated in the Oort Cloud and has spent at least a million years on the inbound leg of its first orbit since leaving its birthplace. Its orbit could be changed through gravitational interactions with other planets in the future.