Eventually, after many passes, the comet may no longer have enough material to form tails. Each time a comet passes close to the sun, it loses more of its ice. The dust tail is the easiest to see with the unaided eye, but occasionally the ion tail is visible as well. The dust particles are pushed away from the comet by solar radiation, forming a dust tail that can be many millions of miles long.
Some of the gas is stripped of electrons and blown back by the solar wind. The gases form a cloud around the nucleus called the coma. The gas flies off the comet, sometimes violently enough to break the nucleus apart, and throws dust up with it. When a comet nucleus nears the sun, solar energy begins to heat the ice and vaporize it. All comets have a nucleus, which is the hard rock/ice object. Comets are objects composed mostly of ice and dust that grow tails when they approach the sun. The majestic comet, accompanied by the crescent Moon (on the right) is setting at twilight over the “sea of clouds” which typically covers the Pacific Ocean, only 12 km away from the observatory. In this extraordinary picture taken from Paranal Observatory, the incomparable view offered by Comet C/2006 P1 (McNaught), which reached its perihelion in January 2007, unexpectedly becoming the brightest comet in the previous 40 years. CometsĬomet McNaught over the Pacific Ocean.
Comets, meteors, and asteroids are often grouped together since they are all basically the same thing: small pieces of rock and/or ice that aren't part of a major planet.