It's remarkable to me that someone peering up at the moon right when this struck could have noticed the flash.
Bright Explosion on the Moon
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Re: Bright Explosion on the Moon
#12And that ladies and gentlemen is why having an atmosphere is a very good thing.
I wonder if the meteorite that exploded in the atmosphere over Russia did more or less damage than if it had struck the earth intact. Clearly Atmosphere makes a good shield for burning up the small meteorites - but I wonder if it exacerbates the damage from medium sized ones?
Define "damage", I guess. It's spread over a larger area, but there's a qualitative difference between widespread broken windows and a local 440 kiloton (per wikipedia) explosion on the ground that will level the surrounding terrain.
Re: Bright Explosion on the Moon
#13oh gawd, transformers has started...
Re: Bright Explosion on the Moon
#14It's remarkable to me that someone peering up at the moon right when this struck could have noticed the flash.
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Re: Bright Explosion on the Moon
#15It's remarkable to me that someone peering up at the moon right when this struck could have noticed the flash.
It wasn't noticed live, the moon was recorded with the help of a telescope and the explosion was noticed later by an analyst.
I also doubt anyone could see that explosion without a telescope as the moon itself is quite bright.
Re: Bright Explosion on the Moon
#16Earlier quoted context omitted.
I wonder if the meteorite that exploded in the atmosphere over Russia did more or less damage than if it had struck the earth intact. Clearly Atmosphere makes a good shield for burning up the small meteorites - but I wonder if it exacerbates the damage from medium sized ones?
Had that impact hit the ground it would have released over 100 kilotons of energy. It would have been far, far more destructive and deadly.
But without an atmosphere the shockwave from that 100 kiloton explosion should be pretty minimal (through the ground only), and any debris flung into the atmosphere would fall right back down on parabolic trajectories (or go into orbit), not linger in the sky for months/years.
The danger posed by such an explosion, off the top of my head, would be getting hit by the object itself, getting hit by falling debris ejected by the explosion, structural damage from the shockwave that traveled through the ground... I'm not sure what else.
Of course without an atmosphere everyone would be dead anyway, so I suppose this is kind of a silly thing to think about.
Re: Bright Explosion on the Moon
#17It's remarkable to me that someone peering up at the moon right when this struck could have noticed the flash.
It wasn't noticed live, the moon was recorded with the help of a telescope and the explosion was noticed later by an analyst. I also doubt anyone could see that explosion without a telescope as the moon itself is quite bright.
In the video, the narrator says that someone looking at the moon would have seen it, even without a telescope.
Re: Bright Explosion on the Moon
#18I saw this once. It was quite a few years back, through my 8" dob in my front yard. I saw a flash and couldn't imagine what it could have been except an impact.
After some research online that night I began to doubt myself, most people concluded it was too rare and would not be visible.
The next day I saw someone asking in a newsgroup about the mysterious flash he had seen the night before while observing the moon through his telescope. Again, the general consensus was that he couldn't have seen an impact, it was too rare and would not be visible.
I checked with him and we both saw the flash at the same time.
I also saw a satellite transit the moon once with that same telescope, it was so cool.
And to think I don't even pull it out anymore. Sad....
Re: Bright Explosion on the Moon
#19Earlier quoted context omitted.
Had that impact hit the ground it would have released over 100 kilotons of energy. It would have been far, far more destructive and deadly.
But without an atmosphere the shockwave from that 100 kiloton explosion should be pretty minimal (through the ground only), and any debris flung into the atmosphere would fall right back down on parabolic trajectories (or go into orbit), not linger in the sky for months/years. The danger posed by such an explosion, off the top of my head, would be getting hit by the object itself, getting hit by falling debris ejecte…
Of course without an atmosphere everyone would be dead anyway, so I suppose this is kind of a silly thing to think about.
Just never walk out of your front-door without wearing your space suit.
Re: Bright Explosion on the Moon
#20Can someone explain to me why this would be bright? I understand that this should send up a fair amount of ejecta but wouldn't most of the light be just from a reflection of the sun off of the particles? If so, this isn't much of an explosion - it's just the most significant impact we've seen so far. I guess explosion is more interesting to the every-man.
Consider the absolutely insane energies involved - the report says "The 40 kg meteoroid measuring 0.3 to 0.4 meters wide hit the Moon traveling 56,000 mph."
That's a thing roughly half the size of a fridge. Traveling at a speed of about 25 kilometers, per second, coming to a full stop.