Explosion on Moon Spreads Moondust

Jotii writes "NASA scientists have observed an explosion on the moon. The blast, equal in energy to about 70 kg of TNT, occurred near the edge of Marethe Sea of Rains on Nov. 7, 2005, when a 12-centimeter-wide meteoroid slammed into the ground. The main danger of such explosions is the static and toxic moondust, which is thrown around."

Comments

Danger?

[Tx]

The main danger of such explosions is the static and toxic moondust, which is thrown around.

Danger to whom exactly? Should I be hitting the bunker to dodge that toxic moondust?

How do they know the size and speed of the object?

[MichaelSmith]

Obviously they can calculate the objects kinetic energy from the intensity of the flash. This will give them mass or speed, but not both. Perhaps the speed came from their assumption about the origin of the meteoroid, but that could still be wrong, of course.

BTW if anybody is interested in exactly what it was like to be walking on the moon in the 60's and 70's I recommend they have a look at the Apollo Lunar Surface Journal

Toxic moondust, eh?

[wampus]

1. Who did NASA feed the moondust to to determine it is toxic?
2. If you are inside on the moon, one would presume the dust isn't
3. If you are outside on the moon and this happens, you just had 70kg of TNT dropped on you. Getting exploded is your primary concern, followed by death, with moondust toxicity being an also ran

This is why you should keep your helmet on

[harlows_monkeys]

For the foreseeable future, any life on the moon will be in a spacesuit that is completely sealed, or inside a building or ship that is completely sealed. So, would toxic moondust be a problem?

I suppose one might have to be careful when opening an airlock, lest moondust enter the airlock and then spread to the inside of the ship, but without an atmosphere, any dust blown up will settle quickly, so a simple rule of not opening an airlock right after anything nearby explodes should be sufficient.

Or is the risk that it will get on the outside of suits, and be hard to clean off, and so will be carried in?

Re:Not an explosion ...

[pnewhook]

a rock slamming into another rock does not cause an explosion

Yes it does. The force of the impact is great enough that it vaporizes the ground around it. This molten rock cloud then expands and rapidly cools releasing a huge flash of light as it does so. In short an explosion, albeit one without sound.

Same old, same old...

[HiyaPower]

the chronicle of gervaise

18 June 1178 (Julian calendar)

In this year, on the Sunday before the feast of St. John the Baptist, after sunset when the moon has first become visible, a marvellous phenomenon was witnessed by some five or more men who were sitting there facing the moon. Now there was a bright new moon, and as usual in that phase, its horns were tilted towards the east and suddenly the upper horn split in two. From the midpoint of this division a flaming torch sprang up, spewing out, over a considerable distance, fire, hot coals and sparks. Meanwhile the body of the moon, which was below, writhed, as it were, in anxiety, and, to put it in the words of those who reported it to me and saw it with their own eyes, the moon throbbed like a wounded snake... Then after these transformations the moon from horn to horn, that is along its whole length, took on a blackish appearance.

One (controversial) interpretation of this narrative, first suggested by Dr Jack B Hartung some 800 years later, is that it is a description of a crater impact in progress. The "upper horn split in two" is the apparent effect of a plume of dark dust or vapour, the "flaming torch [of] hot coals and sparks" describes the molten ejecta, and the way in which the rest of the Moon "writhed", "throbbed" and eventually "took on a blackish appearance" could be the effects of a temporary lunar atmosphere of gas and vapour created by the impact.