This fall, October 19, the comet will fly past Mars at a distance of only 86,000 miles (138,000 kilometers), which is about a third of the distance between the Earth and the Moon. NASA anticipates this event, as it will be a great opportunity to be observed from the surface of the red planet by robots (such as ESA), but until then it’s possible to observe the celestial body only from telescopes, including using the Hubble photo March 11th.
Comet C / 2013 A1, named Siding Spring, has a tail about 12,000 miles (more than 19,000 km) long and was discovered by astronomer Robert McNaught from an observatory in Australia. The photograph of this comet, taken last year, was processed, which made it possible to discern two separate jets emerging from opposite ends of the nucleus.
Measuring these jets will help astronomers determine the rotation of the core of Siding Spring, which is an important factor for comets, as this affects their appearance and orbit. Siding Spring will reach its perihelion on October 25, six days after its passage next to Mars. After that, it will begin its journey back into the depths of the solar system.
The picture taken by the Hubble Space Telescope was taken when Siding Spring was orbiting Jupiter.
At that time, the Siding Spring cannot be seen with the naked eye from the Earth; on Mars, the comet will create a grandiose show for spacecraft. In fact, at one point it was thought that Siding Spring could collide with Mars! Further calculations have shown that this will not happen.
Observations of comets are crucial for determining the exact trajectories of these icy space objects. In the end, several decimal places can decide whether a comet will collide with a space body or fly past.