New Image Reveals Comet ISON Sticks Together as it Hurtles Toward Sun

Comet ISON could be the comet of the century as it hurtles toward our sun. Now, though, a new image of the sunward plunging ISON seems to show that the comet is intact despite some predictions that the fragile icy nucleus might disintegrate as our nearest star warms it.

The comet was first discovered on September 21 2012. That's when Russian astronomers spotted ISON using a telescope with the International Scientific Optical Network. At the time, the researchers predicted that the comet would fly past the sun at a distance of just 2.7 solar radii.

Since then, the comet has continued its trek toward our sun. In this latest NASA image, taken by the Hubble Space Telescope on October 9, the comet's solid nucleus is unresolved because it's so small. Yet if the nucleus had broken apart, then Hubble would have likely seen evidence for multiple fragments. This means that the nucleus is likely still intact.

In addition, the coma or head surrounding the comet's nucleus is symmetric and smooth. This would probably not be the case if clusters of smaller fragments were flying along. What's more, a polar jet of dust first seen in Hubble images taken in April is no longer visible and may have turned off.

The latest color composite image was assembled using two filters. The comet's coma appears cyan, a greenish-blue color due to gas, while the tail is reddish due to dust streaming off the nucleus. The tail itself forms as dust particles are pushed away from the nucleus by the pressure of sunlight. Already, the comet is about 177 million miles from Earth.

So we can we expected to see this comet? It will make its closest approach to Earth on December 26 at a distance of 39.9 million miles. But it will be most visible during the end of November and early December. Assuming ISON doesn't fall apart, we may be in for a spectacular light show.