Comet Holmes Now Larger than Sun
Exploding Cometary Debris Has Become Biggest Solar System Object
Comet Holmes is now greater than the size of the sun and continues to be easy to spot in the night sky.
Comet Holmes Becomes Solar System's Biggest Object
The Sun is no longer the largest object in our solar system. Comet Holmes is temporarily the title-holder, having expanded to a diameter of 1.4 million miles, according to the most recent measurements by the University of Hawaii. However the Sun is still the most massive object in the solar system, although not the largest. Comet Holmes' ever-widening girth is made up of diffuse dust and gas that is not dangerous to Earth or any other planetary body. However it does make the comet easy to see in the night sky.
Hubble Images the Giant Comet Holmes
Comet Holmes first began its sudden expansion on October 23. Hubble took images of the newly bright comet on October 29, 31, and November 4. The comet has brightened nearly a millionfold, spewing off gas and dust. The Hubble image shows that the dust is thicker across Holmes' middle, giving it a bow tie appearance.
The nucleus of the comet is veiled by the layers of dust coming off. Hubble is mostly seeing light reflected off this dust. Hubble had previously imaged Comet Holmes in 1999, long before it began its current outburst. At that time it was measured as having a diameter of 3.4 kilometers. Comparison of the new images with the old may help astronomers determine how much of the comet is left after this major outgassing, and how much might have blown off in the process.
Finding Comet Holmes in the Sky
Anyone who wishes to observe Comet Holmes can find it pretty easily, although a darker sky will help. In mid-November, the comet is positioned in between the W shape of the constellation Cassiopeia in the northeast and the star cluster of the Pleiades in Taurus in the east. The comet itself lies in the constellation Perseus, and is quite close to its brightest star, Mirfak. On November 19 Comet Holmes's large fuzzy shape will be right next to the brighter pointlike Mirfak.
Comet Holmes can be distinguished from the stars by its wider, hazy appearance. Although it is as large as the sun with its expanding bubble, it does not appear as big as the sun in our sky. It looks a bit wider than a typical star and is not pointlike.
Read the article Comet Holmes Suddenly Brightens and the related blogs (including a November 15th observing report) to learn more about the comet and how to see it.
References: University of Hawaii, Hubble News
