NASA’s Hubble Space Telescope has captured some amazing and breathtaking images since it began scanning the cosmos in 1990. But, from late last year into early this year, the space telescope was able to capture and record something that, until now, had never been seen before; the breakup of an asteroid located in the asteroid belt between Mars and Jupiter.
Sure, many astronomers have been able to watch comets break apart as they come close to the sun, but they’re much more fragile than asteroids. Comets, which are basically dirty snowballs, are made mostly of ice and dust. Asteroids, on the other hand, are chunks of solid rock made of more durable material such as clay, silicate and nickel-iron. So asteroids are less likely to simply break apart than comets.
“This is a rock, and seeing it fall apart before our eyes is pretty amazing,” said David Jewitt of the University of California at Los Angeles, who led the astronomical forensics investigation.
Designated P/2013 R3, by the International Astronomical Union (IAU), the disintegrating asteroid, was first spotted on September 15, 2013 as an unusual and fuzzy-looking object by astronomers with the Catalina and Pan STARRS sky surveys located in Tucson, Arizona and Maui, Hawaii respectively.
Following-up on these observations about two weeks later scientists with the W. M. Keck Observatory, located atop Mauna Kea, a dormant volcano located on the island of Hawaii, spotted three astronomical bodies moving together and were enveloped in a cloud of dust that was as big as the diameter of Earth.
“The Keck Observatory showed us this thing was worth looking at with Hubble,” said Jewitt. “With its superior resolution, space telescope observations soon showed there were really 10 embedded objects, each with comet-like dust tails. The four largest rocky fragments are up to 400 yards (365.76 meters) in diameter, about four times the length of a (American) football field.”
The Hubble provided data that indicated that the asteroid fragments slowly wandered away from each other at a speed of nearly 1.6093 kilometers-per-hour.
Astronomers said that the P/2013 R3 actually began breaking apart sometime early last year, but newer images of the broken-up asteroid have shown it to split into even more pieces since.
The breakup of asteroid P/2013 R3 (NASA/ESA Hubble Space Telescope)
The break-up of the asteroid, according to those who’ve been observing it, is not likely due to it colliding with another asteroid, because if it had the fragmentation would have been quicker and much more violent compared to its slow and gradual destruction.
The astronomers also noted that such a smash-up of two asteroids would produce debris that would probably travel much faster than what they had observed.
They also don’t think the asteroid became unglued and fell apart because of the pressure of its interior ices warming and vaporizing.
So, this left the astronomers to consider something that’s been discussed before, but never directly observed. Perhaps the asteroid disintegrated because of what was described as a subtle effect of sunlight, which gradually speeds up the asteroid’s rotation rate. As the asteroid continues to spin faster and faster, centrifugal force kicks and causes the asteroid to gradually pull itself apart.
For this self-destruct scenario to work, astronomers say that the P/2013 R3 had to have had a weak and fractured interior that was most likely caused by a number of non-destructive collisions with other asteroids.
Scientists are now figuring that most small asteroids in our solar system were probably severely damaged in this way. The break-up of the P/2013 R3, they said, was most likely due to such an asteroid to asteroid collision that took place sometime within the last billion years.
Looking back at another occasion when they saw six tails springing from asteroid P/2013 P5 along with what they’ve observed with P/2013 R3, astronomers said that they are finding more proof that the pressure of sunlight could very well be the primary factor that has caused our solar system’s small asteroids, those less than 1.6 kilometers across, to disintegrate.
Those following the destruction of P/2013 R3 figure that the remaining debris from the now broken-up asteroid probably weighs about 181,437 metric tons and will mostly likely become a source of future meteoroids.
Astronomers’ figure that most of the remaining debris will eventually plunge into the sun, but a small amount of what’s left of asteroid P/2013 R3 may someday provide a spectacular show for us as they blaze across the sky as meteors.