Expert: Ed - 6/7/2007

Question
QUESTION: I am interested in how different lava would look like if it cooled in outer space (specifically the moon).   I understand there are many kinds of lava and that this is a little studied subject.   However, I am hoping that studies of lava fields in extremely high altitudes on Earth could lend some clue to how lava would react to being suddenly exposed to the extreme cold and vacuum of space.   I am also interested in what a lava flow miles from the source of the flow would look like under the same conditions.   Would it look the same as it does on Earth or would it be radically different?   Bottom line this question, would the lava look hard and smooth like glass or rough and bubbly like pumice?

ANSWER: Kurt,

This is a very specific question calling for specialized expertise (beyond mine).  I don't want to steer you wrong, so I'm recommending that you look elsewhere.  But here are some good places to get you started, at least.

Have you thought about investigating the formation of the moon itself?  That happened in a very similar scenario to what you're describing.  Look at this NASA link, especially questions 6 through 9.
http://curator.jsc.nasa.gov/lunar/lunar10.cfm

I notice that anorthosites are mentioned as being prominent on the lunar surface.  A little research shows that these rocks are igneous, and coarse grained, so, more like pumice than glass.  That seems like it should be useful to you.  Try googling "anorthosite igneous lunar," and see what you get.

This intriguing NASA website discusses the possibility that the moon may still be geologically "alive," or, still undergoing the kind of processes that you are interested in.
http://science.nasa.gov/headlines/y2006/09nov_moonalive.htm

If you really have a need to know about this, maybe you could try contacting the scientific investigator mentioned in that article, Peter Schultz.  Don't tell him I sent you, please.
http://research.brown.edu/myresearch/Peter_Schultz

I hope this helps you get started.  I'd be interested to hear how you answer this question, if you feel like letting me know.

Best wishes, and Keep Looking Up!
--Ed

---------- FOLLOW-UP ----------

QUESTION: Thank you for answering my question.   I found it very helpful.   I heard a theory from another expert that lava exposed to the environment of space near the Sun (at the distance from Earth to the Sun) would slowly “erode” the lava over geologic time.   He suggested that the lava would slowly be eroded by constant bombardment from solar radiation and the tremendous heating and cooling between the lunar night and day.    The end result would be that the lava would be reduced eventually to an amorphous grey powder.   This seems to make sense since we found lots of grey powder on the moon.   Do you concur?

Answer
Kurt,

Hi again, sorry I'm a little slow getting back to you.

Again, I am not an expert on this specialized topic.  However, a NASA link I found suggests to me that the other person you spoke to might not be correct.  Hey, I still respect him for attempting a hypothesis, there would be no science if people did not do that.  And he could be correct, and I could be wrong.

Look at this link.  Scroll down just a little, and look at the paragraphs just to the left of the first photo of a dust particle, and slightly below the photo also.
http://science.nasa.gov/headlines/y2006/19apr_dustbuster.htm

It sounds like the other person you talked to is partly right.  Apparently the sun's radiation DOES have an effect on the dust.  It gives it an electrostatic charge.  However, the sun's radiation is not the reason for the dust's existence in the first place.  Evidently, the dust is formed when meteors strike the lunar surface, blasting rocks into hot glass, then breaking the rocky glass into tinier dust particles.

Well, if that's what they say at NASA, that's good enough for me!

Keep Looking Up,
--Ed