The Dark Twin

German astronomer Johannes Kepler, court mathematician to holy Roman Emperor Rudoff ll, was astounded with the object he saw through his newest telescope on October 17, 1604. There was an object in the heavens brighter than all the other stars in the sky. Johannes Kepler knew he was looking at the explosion of a supernova, but he had no way of knowing that this supernova was in his own backyar. Nor could he know it would be the last stellar blast to occur in Earth's vicinity thorughout known history.

Our Milky Way, a spiral galaxy, contains over a hundred billion stars. Supernovas are rare, even wtih such a large number of stars. Astromomers expect only a few such explosions to be seen each century, as clouds of dust and gas obscure the view of much of the galaxy. Only the supernovas within a few thousand light-years of Earth can ever be seen.

If only Johannes Kepler could have traveled through his telescope and through time to see the star explode, this is what he would have observed. The star was a thermonuclear cladron collapsing upon itself as it used up the last of its energy until finally, the star tore itself apart. A supernova radiates so much energy---over five billion times the annual energy output of our sun--that it briefly rivals the entire galaxy of stars in  which it occurs. The explosion transforms the star into a shell of hot gas that initially expands at speeds of 6,000 miles per second or more. Supernovas not only mix and heat the interstellar medium, but they may provide the hammer blows that initiate the collapse of molecular clouds and trigger the formation of new stars.

If Kepler could have seen this process, he would have seen a shock wave expanding, tearing apart everything in its path---including a large rocky planet seven light years from our solar system. As the shock wave hit the planet, it shattered into a million pieces and flung the pieces to the far reaches of the universe. One large rock from this shattered planet, 140 kilometers in length, was sent hurling toward a far distant, medium-sized sun, which the rock will be meeting in 400 years. Tucked within the gravitational pull and in the shadow of this giant asteroid was a silent dark twin, three kilometers in length, made of solid iron. 

Scott Allen rubbed his weary eyes before removing another packet of computer-generated pictures taken of the sun the week before. Generally, Allen would have examined and cataloged each picture the day after the film was ready. But with so much going on in the last month, he felt lucky to even have the time to look now. Once a day, a different student of his would program the computer to look at a different part of the sun for flares. One set of prints was left unopened; a student had noted this set was programmed incorrectly and the field was too narrow to get the full flare. 

Sipping a cup of cold coffee, Scott bent forward and began to look at the pictures from last week. Predictions called for small solar flares this time of the year, and nothing was out of the ordinary in the first 23 pictures. On the 24th picture, two small streaks of light appeared just above the small flare, where no light should be. Allen almost missed the anomaly, slowly, Allen pulled the picture under the glass to get a better look. Stars couldn't have made that kind of anomaly. They are stationary in the sky, at least for all practical purposes on a time exposure of less than a few hours. It looked like the streaks might be asteroid tracks.

Scott spent a few minutes making sure that his calculations were correct before he pulled up a picture on the computer screen that should match the one he had under the glass. However, the older picture in the computer did not match the other; it showed no streak of light where the newer photograph did. A smile spread across Scott's face as he typed the calculations into the main computer. He found no notification of an asteroid sighting in this sector, no announcement from the scientific world. He had found his first asteroid! His first two, actually; each streak of light marked one asteroid.

Allen paused for a moment when he saw the date on the picture. It was taken seven days ago. Someone should have noticed and verified the two asteroids within two hours. Why no reports?