... In the Heart of the Tarantula Nebula . ... In the heart of monstrous Tarantula Nebula lies huge bubbles of energetic gas, long filaments of dark dust, and unusually massive stars. In the center of this heart, is a knot of stars so dense that it was once thought to be a single star. Possible Mud Volcanoes on Mars . ... Is this a mud volcano on Mars? ... First of all, hills like this seem to better resemble mud volcanoes on Earth than lava volcanoes and impact craters on Mars. ... 2007 2008 . ...