Moon Landings: why is there no dust in the lander pads?

[tdn]

@ivan astikov

Yes, because righteous indignation is definitely the only way to confound ignorance, isn’t it!

When logic, terms that a 4-year-old could understand, and repeated explanations fail to confound ignorance, righteous indignation is about all that is left.

You keep talking about billowing clouds, and that has been debunked at least two dozen times in this thread alone. You seem unable to grok that very simple concept.

So please explain to us how dust will billow in an atmosphere-free environment. We’d love to learn from you.

[Left_Hand_of_Dorkness]

@where's the subscription info?

Of all those billons of particles, the pads don’t even end up with a fine mist of a covering containg your ‘small number’?

Please reread what you quoted:

@puppygod

That would be very, vary small number of them. Certainly not enough to see on the photo of such resolution as linked.

Yes, there were probably a nonzero number of particles on the pads, particles that flew out, bounced off a perfectly-angled surfaced, and came back to land on the pads. It’s fairly unlikely that there were enough particles who hit the perfectly aimed surfaces such that you’d be able to see the results.

Daniel

[Mangetout]

@where's the subscription info?

You clearly think like me. Not all of the ‘dust’ would be sub-sonically blasted away and therefore, the particles that aren’t under such propulsion would… maybe bounce around, maybe go straight up vertically past the lander… maybe hit rocks lying on the floor just outside the perimiter of the 4 pads where they’d ricochet back.

Of all those billons of particles, the pads don’t even end up with a fine mist of a covering containg your ‘small number’?

Right, because that’s exactly the same argument as you’ve been using throughout the thread, when you were going on and on about ‘billowing clouds’ isn’t it?

[ivan_astikov]

Neither of those links shows me how moon dust behaves when it is subjected to the thrust of a rocket, so they are not really conclusive of anything.

[Alessan]

Right, because moon dust obeys its own special laws of physics.

[ivan_astikov]

@tdn

When logic, terms that a 4-year-old could understand, and repeated explanations fail to confound ignorance, righteous indignation is about all that is left.

You keep talking about billowing clouds, and that has been debunked at least two dozen times in this thread alone. You seem unable to grok that very simple concept.

So please explain to us how dust will billow in an atmosphere-free environment. We’d love to learn from you.

I haven’t mentioned ‘billowing clouds’ in any of my posts; you have me confused with another poster.

[Czarcasm]

@where's the subscription info?

You clearly think like me. Not all of the ‘dust’ would be sub-sonically blasted away and therefore, the particles that aren’t under such propulsion would… maybe bounce around, maybe go straight up vertically past the lander… maybe hit rocks lying on the floor just outside the perimiter of the 4 pads where they’d ricochet back.

Of all those billons of particles, the pads don’t even end up with a fine mist of a covering containg your ‘small number’?

Where are you viewing these extremely high resolution close-up photographs of the lunar lander pads that show that they are entirely clean, without even the finest bit of dust on them? I can’t seem to find them anywhere.

[Half_Man_Half_Wit]

@where's the subscription info?

Of all those billons of particles, the pads don’t even end up with a fine mist of a covering containg your ‘small number’?

Don’t forget that those billions of particles are all on a ballistic path leading away from the lander, so that each that actually got directed back would need to undergo a succession of collisions, which makes the number that do so very very small indeed.

[Mangetout]

@ivan astikov

Neither of those links shows me how moon dust behaves when it is subjected to the thrust of a rocket, so they are not really conclusive of anything.

Are you actually serious here?

You could make the same argument and say that it only shows the behaviour of a goose feather in air and in a vacuum, and that we therefore have no idea what might happen with a duck feather.

[Half_Man_Half_Wit]

As a thought experiment, what do you think would happen if you directed the air flow from a compressor at a pile of sand on a concrete floor – would you expect to get the floor clean or the sand to ‘bounce back’ and re-cover it?

[ivan_astikov]

@Mangetout

Are you actually serious here?

You could make the same argument and say that it only shows the behaviour of a goose feather in air and in a vacuum, and that we therefore have no idea what might happen with a duck feather.

Are you saying that those video clips resemble in ANY way what would happen to moon dust if it was subjected to a rockets thrust? Please explain what relevance they have to what the OP is suggesting!

[Half_Man_Half_Wit]

@ivan astikov

Are you saying that those video clips resemble in ANY way what would happen to moon dust if it was subjected to a rockets thrust? Please explain what relevance they have to what the OP is suggesting!

Well, they conclusively show that the moon dust would travel along a ballistic path, and hence, that there shouldn’t be any dust buildup on the lander’s pads.

[tdn]

@ivan astikov

I haven’t mentioned ‘billowing clouds’ in any of my posts; you have me confused with another poster.

Oops, sorry. I did, indeed, confuse you with where’s the subscription info?.

[nd_n8]

@Mangetout

Are you actually serious here?

You could make the same argument and say that it only shows the behaviour of a goose feather in air and in a vacuum, and that we therefore have no idea what might happen with a duck feather.

Good point, what if it was a duck feather. Or a chicken.

::Grabs compass and slide rule and starts furiously plotting mass/vector graphs recompensating for the effects of poultry::

Yes… chicken…

[slaphead]

@ivan astikov

Are scientific replications of these effects online anywhere?

I remember seeing a very cool TV documentary on meteors etc. that did simulations of impacts by solid and crumbly objects on various kinds of targets. Can’t remember the show though. One of the things they did was firing a high-speed projectile into fine powder in a chamber, both with and without atmosphere. With atmosphere this produced a big cloud of dust and a small crater with soft outlines. Without atmosphere it basically did what you can see on page 2 of this PDF (Deep Impact (EPOXI) - NASA Science) - a big inverted-cone scatter with no cloud at all leaving a larger, crisper crater (because virtually nothing came down into the impact site). The two looked radically different.
Maybe it would help if you imagine dropping an anvil into a swimming pool full of buckshot - the amount of lead pellets that would go straight up and down would be minimal, because they would be pretty much unaffected by airflow - they’d nearly all go sideways, and all of them would go in ballistic arcs. Scale the particles down and they’d behave pretty much like that on the moon.

[Mangetout]

@ivan astikov

Are you saying that those video clips resemble in ANY way what would happen to moon dust if it was subjected to a rockets thrust? Please explain what relevance they have to what the OP is suggesting!

Put simply, the clips demonstrate that in the absence of atmosphere, things we normally consider to be floaty are not floaty at all - they drop like rocks.

In the absence of atmosphere, particles of dust will not remain suspended in the air, because there is no air.

[where_s_the_subscription_info]

@Enfant Terrible

No, because there is NO ATMOSPHERE to resist the flight of the dust particles, no matter how tiny. No resistance, no cloud, no way for the dust to drift back to the landing pads.

You all basically say 'You f’ed up WTSI as there’s no atmospere therefore there’s no ‘bollowing’. Allow my retort.

You all have it too tidy and you don’t heed the chaos theory* and I’m starting to think you all belong to NASA or something, Area 51 employees? Dunno. Definitely some group think going on here. Are you the same guy with 5 or 6 logins?

Anyway, a rocket, equivalent (according to one of your own ‘believers’) says the lander needed approx 3 times the power of a Bell range equiv helo and that’s into one of the lightest dust-like substances I know (it being talc-like… not sand-like or grit like) So we get all this thrust stirring up go knows what dust and nothing, by chance, nothing rebounding of a leg, nothing off a stray boulder, nothing of the underside of the lander gets bounced into those pads?
Yes, we only have the small web versions of the pad images as ‘they know’ not to release the biggies! Release the biggies and you’ll all be ‘signing on’.

http://www.youthinformation.com/Templates/Internal.asp?NodeID=89923

You say dust in 1/6th gravity won’t ‘billow’ and that if it did, the a’nauts would have kicked it up when ‘walking’. The same guy then says that 'it doesn’t billow and falls to the ground. Exactly my point. Whatever goes up wll come down on the moon. [goes looking for .mov or a’nauts loping along]
Clip: http://www.youtube.com/watch?v=Wnwz51Y9VJg&feature=related

I invite you to watch the first 4 mins or so. It’s all the clips you’ve seen before… but look at the rover wheelspinning and watch the ‘sand’ it kicks up. Likewise, watch the guy loping along again kicking up sand and watch where that goes. Other than that, I’ve no more opinions on the lip as 'it looks like sand would beave if a guy kicked it up on a beach.

I’ve watched clips of the lander landing and there’s no billows that can be seen but then what am I seeing? It looks like the sand is being blown horizontally away fro rocket (like you all say) but you could also interpret that clip and say the dust looks like it then goes vertically. You decide.

But I have to ask, how can I trust that that’s real and not some mock-up made here on earth?

• I never thought I’d get to use that term in a clever sentence.

p.s good job I never brought up the appollo craft confronted by a fleet of UFOs behind the darkside of the moon (where we couldn’t see them).

[where_s_the_subscription_info]

@ivan astikov

I haven’t mentioned ‘billowing clouds’ in any of my posts; you have me confused with another poster.

I hope he doesn’t mean me? :rolleyes:

[where_s_the_subscription_info]

@tdn

Oops, sorry. I did, indeed, confuse you with where’s the subscription info?.

Damn! :smack:

[Mangetout]

@where's the subscription info?

You all basically say 'You f’ed up WTSI as there’s no atmospere therefore there’s no ‘bollowing’. Allow my retort.

You all have it too tidy and you don’t heed the chaos theory* and I’m starting to think you all belong to NASA or something, Area 51 employees? Dunno. Definitely some group think going on here. Are you the same guy with 5 or 6 logins?

Is this supposed to add credibility to your arguments? It’s not working.