Comet ISONCredit: NASA Hubble

Comet ISON was discovered in late 2012 by  Vitali Nevski and Artyom Novichonok at the International Scientific Optical Network, (ISON), in Russia. Preliminary calculations were made which established that the comet would come very near the sun in late November 2013. In fact, the data suggested that the close approach would result in extensive heating of the item. When other close comet approaches to the sun have occurred, the results have been quite spectacular. Comet ISON was potentially going to be epic. If predictions were right, the resulting coma would be very prominant in the night sky for viewers in the Northern Hemisphere. Time would tell.

During the year after the discovery, further research was made by astronomers. While predictions of a very bright coma continued to dominate the scientific community, some reports were made that suggested an entirely different outcome. Some astronomers suggested that ISON could potentially be a major disappointment. By virtue of its passing so close to the sun, and due to the small inherent size of the object, there was a real possibility that it would be virtually, (or completely), destroyed as it travelled to the sun. In the end, these reports seem to have been proven correct.

Comet ISON was on a orbit which would take it from the farthest reaches of the solar system to the immediate vacinity of the sun. In fact, at closest approach, it would be within 724,000 miles of the star's surface. At such a separation, the temperature would be very high, solar winds, and gravitational forces, would be very strong. The small nucleus size, 3 miles in diameter, would possibly not be sufficient to withstand the conditions. While not quite a sun-grazing item, ISON was in the danger zone, for such a body.

At the end of November, 2013, the Big Day happened. The comet travelled close to the sun. For a couple of days, it was completely invisible since it was in the daytime glare. Time would tell whether it could survive. After November 29, astronomers would look for the distinctive coma, or lack of one. If the object survived, the view in the night sky would potentially be as stunning as any in history. If it did not survive, the show would be over.

Alas, the close approach to the sun proved fatal for Comet ISON. Despite the hopes of many in the field of astronomy, the visiting object was not able to withstand the head, solar wind and gravity that it experienced. The small object was torn apart. The dazzingly show that was to be was over before it could even get started. Far from being compared to Halley, Hale-Bopp, or others, this astronomical visitor could only be compared to wispy clouds that you might see at sunset, and it would not even be as spectacular as that. No, this object was rendered inert by our star.

Other comets in history have passed close by and been quite spectacular[1]. The coma, spreading across the night sky, is one of the brightest sights in astronomy. It is quite unlike any other display in the sky, being more like the Northern Lights than any other astronomical event. Ironically, other celestial visitors have actually passed closer than this one. Some have even collided with the sun in years past. At least this visitor did not meet that particular fate.

NASA reports that perhaps ISON did not break up entirely. Reports are now published which describe small surviving components, fractions of the original body. These may yet provide some scientific value to the astronomy field. Further study of the debris is to be carried out for some time in order to learn whatever is possible from this object. Analysis of the coma can reveal much. There could be quantities of water and other materials. Most such objects are icy so water is practically a certainty. How much may never be known, of course, due to the demise. The study of other particles may be able to detect particular elements as well.

The next scientific opportunity for ISON comes in mid January, 2014. At that time, the Earth will pass near the orbital path. Residual debris may then be detected by scientific instruments. A meteor shower may also occur. Because the bulk of the material was destroyed by the sun, however, there may be little left to observe in January. Astronomers will study the sky, regardless, hoping to make a determination of meteors which could be tracked back to ISON. If so, this would be a rare event. Most meteor showers occur when the Earth passes through coma trails that have existed for countless years. To have one event happen just weeks after the close approach is a rare, (or even unique), possibility.

If Comet ISON had survived the close approach to the sun in November, 2013, it certainly would have become a famous astronomy feature. The object had the potential to be an amazingly bright night time visitor. These displays have dazzled people for many centuries and many such events have been legendary. This one was potentially going to be as spectacular as any that had come before, or that would ever happen in the future. The hype did not match reality, however. The conditions presented to the object as it neared the inner portion of the solar system proved to be too much. The object was actually far to small to withstand these harsh conditions. As a result, the show never materialized. It could have been glorious, but was not. These types of events do happen from time to time. Someday, and with little notice, another visitor from the far reaches of space will drop by. It will produce a bright coma tail, visible as a wide swath in the night sky. That future visitor will be observed, and remembered, by viewers at that time. Science will be advanced. Many millions of photographs will be taken. The glory that was to be for ISON will, instead, belong to another yet un-named item. [1]

Comet ISON PathCredit: NASA
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