But it is regarded as extremely unlikely that even the nucleus consists of a uniformly solid mass. If it were such, comets would be far more formidable visitors when they pass near the planets than they have been found to be. After the nucleus has been formed it begins to throw out bright jets directed toward the sun. A stream, and sometimes several streams, of light also project sunward from the nucleus, occasionally appearing like a stunted tail directed windows 7 ultimate sp1 x64x32 en to the real tail.