Within a few months after discovering a comet through a pair of high powered binoculars, Japanese amateur astronomer,Yuji Hyakutake, discovered Comet Hyakutake, virtually in the same position in the sky. The next day he reported his observations to the National Astronomical Observatory in Japan and within days the findings were confirmed by independent observations.
The Great Comet of 1996, as Hyakutake’s comet was called, usually makes an orbital passage through our solar system every 17,000 years but, because of the gravitational pull of larger planets this trip has changed to nearly 70,000 years.
Over the last 100 years, the Great Comet of 1996, was one of only four comets to pass this closely to earth. With its tail nearly 360 million miles from its nucleus, Hyakutake’s comet was estimated to have passed through the inner solar system, only .01 astronomical units from the earth on March 25. After passing by earth in March, by May 1, 1996, the comet was almost near the sun, beginning another round trip orbit that would sometime in the future bring it closer to earth, once again..
Unexpectedly the space craft, Ulysses, crossed the comet’s 360 million mile tail as it neared the earth’s inner solar system. One of the most surprising scientific discoveries observed during comet Hyakutake’s near-earth trip was that X-rays were emitted and assumed to be caused by the interactions of solar wind particles and neutral atoms in the comets coma. Since then, every comet observed by scientist is emitting X-rays.
“Ulysses passed through the comet’s tail in May of 1996, however evidence of the encounter was not noticed until 1998, when astronomers analyzing old data detected a large drop in protons passing, as well as a change in the direction and the strength of the local magnetic field. Some other terrestrial observers analyzing data from the comet found ethane and methane, the first time gasses were found comets and there was deuterium found in the comet’s ice that indicated concentrations much greater than found in the oceans of the world”, according to scientific reports in Wikipedia.
Since the discovery of Comet Hyakutake, the United States through NASA and the European countries have launched space craft that will do fly-bys and intricate explorations of comets in deep orbits in outer space. One European project, Rosetta, launched in 2003, was expected to study comet 46P/Wirtanen for two years and then attempt deploying a rover to its surface.