http://www.smh.com.au/news/national/friday-13th-asteroid-a-close-call/2006/07/01/1151174439124.html

 

So on July 3 a 400 meter wide asteroid is to pass within 430,000 km of earth and another is predicted pass within 35,000 km in 2029.

 

There's been a lot of speculation as to what would happen if such an object hit the earth. My question is...what would happen if such an object hit the moon? Given that the moon has a smaller mass and does not have an atmosphere to protect it, would the mass of such an asteroid be sufficient to change the moon's orbit, cause a large loss of mass or severly fracture the surface? Maybe we'd just get a really cool show...

 

Thanks,

 

Rich

 

The moon gets hit all the time. Your assumptions are correct that the moon is unprotected due to it's lack of atmosphere, and also can't cover it's scars because it's geologically dead. If you look at the moon it's covered with craters.

 

 

Here's a NASA video of a relatively small meteor hitting the moon: http://www.spaceweather3.com/swpod2006/14jun06/movie760.gif

 

If it hit the moon I don't think it will significantly change the moon's orbit. It will probably just make a crater and then the Earth's pull on the moon will probably cause a series of seismic events as the moon readjusts.

Thanks. I imagine that a 400m asteroid hit it would liquefy most of the immediate surface area and create a pretty cool show!!

RichF a 400m asteroid would do relatively little to our moon. a little flash and it would be gone. probably the equivalent of a few megatons of TNT. even a 10000m wide asteroid would probably still only scar the surface but it would be a much better light show followed by a meteor shower from impact debris.

Thanks for the information and replies. I was so looking forward to the moon going out kaboom!!!

 

It appears that my friends from Zeta Reticuli will need to find a larger rock!

A 400m meteor is fairly large; debris from the impact could get large enough to hit the surface of the earth. Although I doubt much, if any damage would be done. A much larger object hitting the moon could cause significant damage to earth however.

So, how large would an object need to be to severely damage the moon or force it out of orbit? What vector and speed would be neccessary?

a fair percentage of the moons mass (maybe >2%) and travelling at a hefty speed >17km/s say.

a fair percentage of the moons mass (maybe >2%) and travelling at a hefty speed >17km/s say.

 

Damn it...I'm gonna need a bigger tractor beam!