Quote:
Originally Posted by Cignus
So it occurs to me to see if anyone has calculated the explosive power it required to blow enough dust and gas out to a diameter of what has to be 6 or 8 times the diameter of Mars, enough dust and gas to glow brighter than mag 3! It is mind boggling to me that a cold hunk of dust and ice moving away from the sun, that was mag 17 and did not really do much of anything during its travel close to the sun, and now as it exits halfway to Jupiter it explodes with enough force to through out the volume of dust needed to create the size and brightness. That's not just a couple pounds of evaporating ice! We're talking some serious blast power are we not? Anyone besides me wondering where that power came from?
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I haven't done the calculation. But maybe it isn't all that much force. As you point out, the nucleus of the comet is rather small - its not like there is a big gravitational field the dust has to overcome. What's the escape velocity from a 10 km diameter sphere of ice?
Once it escapes from the surface, there is no resistance (its a vacuum), so the particles would just keep going and the cloud would keep expanding. I suspect someone could calculate a velocity for the how the size of the cloud changes over time.