Instructables
Picture of Your own terrestrial planet without atmosphere
This a simple classroom or science at home project that has a good edutainment value even at primary school level.

The Science Part
Mercury, Venus, Earth and Mars are called terrestrial planets as these have 'land' to stand-on.  We may also add moon to the list. Lunar and Mervury surfaces are highly cratered. These craters were formed about 4 billion years ago when the solar system was just born (about 0.3 byr ago) and taking it's present shape.  At that time there were large number of small bodies flying in the solar system and naturally colliding with the other planets. 

The gaseous planets like Jupiter, Saturn, Uranus and Neptune simply swallowed these debris. But on terrestrial planets these missiles left their mark in the form of a craters. 

On planets like the Earth, Venus and Mars most of these makes were eroded by changing weather on these planets.  Whereas Mercury and Moon, which have little atmosphere, have retained their poke marks. 

Thus - if one goes exploring planets of other suns and come across a planet which has highly cratered surface then it is quite likely that the planet has little or no atmosphere.

Study of these features on the planets has helped astronomer to get insight into how the surfaces of these planets have evolved over a period of time.

The Fun Part
---->>>> begins from the next step

 
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arpruss3 years ago
You know, when I saw the photo for this instructable, I thought it was an astrophoto instructable. It looks uncannily like some of my webcam moon photos (attached)!  The color and texture are good.  Great work!

One difference is that your craters have less of a flat bottom than a lot of the larger moon craters.  Any idea why?
Video4-un_pp.jpgmoon.jpg
Physics does not scale very well in this particular field...
See, if a meteor crashes into our moon, a lot of debris is thrown not only outwards, but also upwards (as you can see it if you dump a heavy stone into water). As gravity pulls it down, it gets spread a little bit... And there is the key: The height compared to the gravitational force is different if you do it bigscale on the moon and smallscale on the earth.

Also on the moon the craters filled up by the millenias of small but constant solar winds... From time to time particles get pulled off the surface and travel a few feet before they fall into a depression and get trapped for another millenia. The bigger the depression the more trapping-effect it has. And a sizeable crater is quite a depression. :)
The Key difference would be material, I'd assume. While this is a fantastic simulation of the formation of a planet (btw, I am definitely going to use this for my 8th grade astronomy class this year), it is just a simulation. There are different forces at work for a large object like the moon being hit at tremendous speeds by an asteroid. The energy released from an impact of an asteroid will usually partially heat up and melt the surface that is hit, especially during the moon's early stages when it was forming and the thin crust was still cooling off. Also debri is usually thrown up and brought back down by gravity. Plaster on the other hand, hardens as it dries out instead of cooling off.
The difference is part material and part scale. Your photo resembles very small craters seen on the moon, while also looking like larger craters found on the moons of Saturn which are made of ice instead of rock. I'm sure that if your instructions are followed on a much larger scale then the craters will look more lunar. I've also gotten Marslike craters by adding a bit too much water.
vnzboy2 years ago
nice project.. but just for the record recent studies have shown that the moon was created more than 5+ billions years ago.. moon rocks were dated at 5.3 billion years old, and the dust upon which they were resting was at least another billion years older.
AlphaRomeo (author)  vnzboy2 years ago
Sorry for the delayed reply.
Well to the best of my knowledge the age of the earth itself is about 4.6 billion years or so (which is also the age of the solar system) and the moon formed due to an impact of a mars size body with the earth about 50 million years later. I think the 5 byr is stretching the age too far back in time.
crudworks3 years ago
I suppose you could put Bicarbonate of soda in the mix for it to create random craters.
It would be interesting to see what it looks like.
AlphaRomeo (author)  crudworks3 years ago
Fantastic suggestion - thanks very much. I will try later this week - I am traveling -
You're very welcome.
As a film maker it's quite tempting to see how realistic one can re-create the Apollo 11 landing.
Obviously the conspirisists will go crazy if I'm successful.
Ohhh you rotter!

You have me thinking of all kinds of things to do with plaster in pizza boxes now, and I REALLY should be doing something much more productive!

Wonder if you could model tectonic movement by casting a thin slab, breaking it, moving it a little and then casting more over the top...

What about sprinkling the surface with dry dust and larger particles...

How about layering different materials like WAX...
(Yes I KNOW wax is immiscible in water, but you don't WANT it to MIX exactly, just make a layer of different texture and flexibility.)

Dammit! On with the rest of my day, but than you for sharing.
carmatic3 years ago
How much work is it to make something like the Face Of Mars ?
Unfortunately, the Face of Mars is less a face, more of just a trick of the light.
Yes, I want to recreate feature on Mars so that when I shine light at it from a certain angle, it will also look like a face
St Jimmy User13 years ago
Mythbusters
After the latest disclosures it seems Mars is not at all redish ;). Personally I don't know how it is.
ilpug3 years ago
This could be a useful method to make terrain blocks for tabletop gaming. I must tell my teacher about this for the Astronomy class he teaches.
AlphaRomeo (author)  ilpug3 years ago
Would you let me know your teacher's reaction?
If we do it, definetely.
-chase-3 years ago

many were talking about filming dust particles due to a new Tutorial on the VCP blog -

Though many make terrains in a 3D app it is nice to know an alternative.

I was thinking too with something you mentioned about it cracking.

It would be kinda cool to allow to crack while filming it drying via stop motion photography. (Taking a shot every 10 seconds etc etc)

or even waiting till it's almost dry - still moist and purposly cracking it.

And another thought maybe you can help with - is there a product that you could make this same effect with that you know of that would be softer.

Another words - it would crumble once dried as opposed to being so hard it "breaks" when it cracks...?

I take it this material used in your instrucable is more like white chalk or plaster of paris... so i'm wondering if there is a softer material one could use that you can think of? That would more crumble... hmmm kinda like a coarser dry mud is what i'm thinking...

any thoughts on that?

and thanx for posting this.
Happy for you it made the Instructables news letter.

-chase-

Aegian24243 years ago
do you make props for movies?
AlphaRomeo (author)  Aegian24243 years ago
No - but I appreciate your asking me this
I am a science educator - astronomy in particular - I use this sort of things get my audience interested.
seandogue3 years ago
(removed by author or community request)
AlphaRomeo (author)  seandogue3 years ago
Thanks very much -
lemonie3 years ago

That is a good effect.
Might make good bathroom tiles....

L
AlphaRomeo (author)  lemonie3 years ago
my be I should try one on a cement - I suppose it also be anti-skid
rimar20003 years ago
Very interesting and fun!

Please read my comment at http://www.instructables.com/id/Discovery-of-an-Amazing-Object-in-the-Sky/