Calling this huge, cosmic streak 'bizarre' doesn't even begin to do it justice. It could easily be mistaken for an alien contrail, or a gaseous jet some heavyweight black hole burped up for lunch. In reality, the mechanism that generated this long, starry string is one, single star that went out in a blaze of glory approximately 1,000 years ago.
Called SN 1006, we are looking at a relatively small section of a large supernova aftershock, which first appeared to viewers on Earth sometime around May 1st, 1006 A.D. People from all across the globe — from Africa, to Europe and the far east — made mention of a bright pinpoint of light appearing out of nowhere in written records. It was also said that this mysterious bright light easily surpassed Venus (the planet once called the Morning and the Evening Star) in sheer luminosity, its only rival was the moon. However, it was easily present during the daytime for several weeks, not fading from view until about two and a half years after-the-fact.
It took almost a millennia for astronomers to ascertain its true nature, when radio astronomers pointed their instruments toward the source and detected a nearly circular ring of material surrounding it — the hallmark of a supernova. Astonishingly, even after all this time, the ring remained very impressive in size; spanning almost 30 archminutes across (which makes its angular diameter equivalent to the moon). Based on this, the astronomers deduced that the blast wave emanating from the supernova outward spread at a rate of 20 million miles per hour.
Today, 1,008 years later, SN 1006 is nearly 60 light-years in diameter, and continues growing at a rate of 6 million miles per hour. "Even at this tremendous speed, however, it takes observations typically separated by years to see significant outward motion of the shock wave against the grid of background stars. In the Hubble image as displayed, the supernova would have occurred far off the lower right corner of the image, and the motion would be toward the upper left," explains NASA.
This tiny section is a filament situated on the northwest edge of the radio ring. "The twisting ribbon of light seen by Hubble corresponds to locations where the expanding blast wave from the supernova is now sweeping into very tenuous surrounding gas," they explain further.
"The hydrogen gas heated by this fast shock wave emits radiation in visible light. Hence, the optical emission provides astronomers with a detailed "snapshot" of the actual position and geometry of the shock front at any given time. Bright edges within the ribbon correspond to places where the shock wave is seen exactly edge on to our line of sight."
See a larger image here.