But there are also these so called “active asteroids”. This rare class of asteroids has puzzled scientists for many years. Active asteroids appear to throw off a trail of dust and debris similar to a comet. In 2010 when a new sub-type of asteroid was discovered to spontaneously eject burst of dust for no apparent reasons, scientists have issued the theory of asteroid weight-loss. The theory is that this phenomenon happens due to what it is called “rotational disruption”.
When an asteroid spins fast enough the existing centrifugal forces are able to exceed their own gravity and this causes the space rock to crack itself and thus begin to break apart. Last August a team of astronomers pointed a large telescope on Hawaii’s Mauna Kea towards P/2012 F5 in order to study such an active asteroid suspected to undergo a rotational disruption. The scientists were able to capture it and have evidence of how the space rock ejected fragments of itself into space. These fragments are seen as they continue to follow the asteroid similar to a comet’s tail.
Their analysis showed that P/2012 F5 rotated for just 3.24 hours but due to the fact that the rotation was fast enough this is what caused the object to impulsively explode. One of the participants in this analysis had the following to say: “This is really cool because fast rotation has been suspected of catapulting dust and triggering fragmentation of some active asteroids and comets… But up until now we couldn’t fully test this hypothesis as we didn’t know how fast fragmented objects rotate”