Page 2 zero. Photo graphs of the area taken from 1930, depict forest trees burnt and flatten thus proving that something very powerful did take place in that area. Considering this was just a fragment of a comet, an over sized large comet impact might potentially be much worse then the Tunguska event. Perhaps for this reason especially we are very interested in the orbits and trajectories of Comets passing through our solar system and nearby our planet. The illustration below is a modified screen shot of a java appet that models a comet orbits at any time in respect to Earth and the Sun. This Screen shot of the java appet shows the C/2006 M4 (SWAN) location in our solar system on December 5th 2006. http://ssd.jpl.nasa.gov/sbdb.cgi?ID=dK06M040;orb=1;cov=0#orb4
Comet C/2006 M4 SWAN was named named after the Solar Wind Anisotropies instrument aboard the SOHO spacecraft that took it's picture.5 It's Orbit is said to be hyperbolic. It's Orbit is said to be hyperbolic. Now that C/2006 M4 (SWAN) has finished swinging around the Sun it is now being
4 http://ssd.jpl.nasa.gov/sbdb.cgi?ID=dK06M040;orb=1;cov=0#orb Visited December 5, 2006 5 http://www.space.com/spacewatch/061026_comet_swan.html Visited December 5, 2006
Page 3 projected out of the solar system. Hyperbolic orbits correspond to eccentricities greater than one. This kind of orbit occurs when a smaller object is traveling fast enough to escape from the gravitational pull of a larger object. When considering Kepler's three laws of planetary motion, one must remember that hyperbolic orbits share many inverse relationships to elliptical orbits.6 It is believed this comet originated from the Oort Cloud. The Oort cloud is a name of a spherical collection of cometary nuclei that is surrounding our solar system. The Oort cloud is about one hundred thousand times as far away from the sun as the earth is. Therefore these bodies orbit at slow speeds (approximately three hundred and sixty kilometers per hour). Occasionally a relatively nearby passing star can affect these bodies and cause their orbits to become highly elliptical (such as comet C/2006 M4 SWAN). When this happens objects from the Oort cloud can “fall” into the inner solar system towards the sun. As it falls somewhere between the distance of the orbits of Jupiter and mars it begins to heat and create the luminous tail and most notably characterizes a comet. Because Comet C/2006 M4 SWAN is a one time spectacle, there is an abundant amount of information in regards to where and when to find it in the night sky and a very little amount of popularized information about it's mass and size and anatomy. As an attractive spectacle people have generally recorded that "The blue color of the ion tail is dominated by recombining carbon monoxide atoms. The color of the coma surrounding the head of the comet is tinged green by slight amounts of the molecule cyanogen."7. These observations can help us describe and understand the composition of Dust and the Gas surrounding the Comet. In all other respects to help us understand the inner workings and anatomy we can assume that generally, Comet C/2006 M4 SWAN is allot like what we would
6 http://www.daviddarling.info/encyclopedia/H/hyperbola.html Visited December 5, 2006 7Robert Nemiroff (MTU) & Jerry Bonnell (USRA) http://antwrp.gsfc.nasa.gov/apod/ap061106.html Visited December 5, 2006
Page 4 expect from a typical comet. A typical comet can be described in five distinct sections; the nucleus, coma, hydrogen envelope, dust tail, and ion tail. The Nucleus is typically between one to ten kilometers wide. It is almost all of the mass of the comet. The Nucleus is popularly thought of as a "dirty snowball" because scientists think it is a fluffy mix of ices and fine dust with a coating of black organic substances.8 In the case of Comet C/2006 M4 SWAN some of the ice is carbon monoxide, and some amounts of the the dust is cyanogen. Other ice compounds might include methane, ammonia, water or carbon dioxide... The surface of the nucleus is very dark in color due to organic compounds. Heat absorbed by the dark compounds fuels the sublimation of ice into gas. The gas from the heat also stirs up dust mixed in with the ice. The nucleus is the source of the dust and gases that the other four sections of the comet are consist of. The coma is the visible head (visual the glowing main body) of the comet. It is basically the gases and the stirred up dusts that vent out with the gases from the evaporation of ice. The coma can only exist when there is the heat necessary to evaporate ice inside of the nucleus. A typical Coma is approximately one million kilometers wide. A hydrogen envelope surrounds the coma. Unlike the coma, this gaseous envelope is invisible. The hydrogen gas is thought to have been dissociated from water molecules in the nucleus of the comet by solar radiation. The Hydrogen Envelope is approximately ten million kilometers wide. The dust tail is caused by light rays bouncing off of dust particles in the coma. These light rays invoke a minute amount of radiation pressure from the sun. This weak force can affect the tiny dust particles because they have almost no inertia. Dust particles are pushed out of the coma in the opposite
8 Daniel Rosa, http://eps.mcgill.ca/~rosad/out/Minor%20Bodies%20of%20the%20Solar%20System.doc Visited December 5, 2006
Page 5 direction of the sun do to radiation pressure.9 The ion tail is caused by electromagnetic radiation giving a positive charge otherwise neutrally charged gas molecules in the coma. These electrically charged gas particles are now affected by magnetic fields. As magnetic fields from solar winds pass through the coma only the charged gases are swept away from with the solar winds. These two distinct tails can point in either the same direction or in different directions. Generally the tails tend to point away from the sun. But the tails do not specifically correspond to the motion of the comet. Recently due the the close proximity of the sun comet C/2006 M4 SWAN exploded in colorful illumination. It has been a beautiful sight. We can think of these last flashes of light as our final good byes from an other wise cold lump of dirty ice. Now that it is moving away from the sun, it's coma and tail are continuing to shrink. It's destiny is not to continue circling the sun until the ice of it's nucleus has exhausted. Nor is it likely to collide with a planetary body in our solar system. Comet C/2006 M4 SWAN is finishing its final trajectory towards it's path out away from the solar system. Because it's orbit is hyperbolic and not a ellipse we shall not see this comet again. We can speculate that it might just shoot out into the empty void never to interact with anything significant again or perhaps the story of this rock is just beginning, perhaps this end is the beginning of a new journey that may one millennial if given enough time be swept off into the gravitational pull of some other large body. Speculation is rife, we can safely say that we don't yet have a clue.
9Daniel Rosa, http://eps.mcgill.ca/~rosad/out/Minor%20Bodies%20of%20the%20Solar%20System.doc Visited December 5, 2006
Daniel Rosa, Minor Bodies of the Solar System, Class Course Notes http://eps.mcgill.ca/~rosad/out/Minor%20Bodies%20of%20the%20Solar%20System.doc Visited December 5, 2006
