Moon colliding with Earth | Universe Sandbox ² Alpha 7 (scale illustration)

[Greenleaf]

Another basic video intended to show the scale of time and speed during a moon earth impact.
Even though the moon comes in at 12 km/s, it still takes 4 minutes for it to travel the initial surface distance of 3000 km and impact. You might find it boring, but then you would be mistaken ;-)

http://youtu.be/M7nonN66gYA

The impact point is beyond the horizon. Just off the western coast of USA while the observer is just off the coast of New York.

Issues are apparent. Guess that is why this is still alpha

[JAW1002]

Just wow.. The effect of the moon's surface melting on impact is stunning, please show more!!!!

[dechireur77]

Beautiful. Continue to share more videos

[Bla]

Beautiful.

By the way, is the music music that's implemented in the program?

[gabriel.dac]

Why does the Moon turn into a Sun when it touches the ground? o.o

And by the way, what happens when the Moon falls on your head? Vid pls

[Breakfestbacon]

The moon isn't turning into the sun, it's becoming very hot and molten.

[smjjames]

Probably would look better if it were shattering with cracks as it deformed or maybe starting to glow from the contact point and radiating from there rather than all at once.

[Breakfestbacon]

Probably would look better if it were shattering with cracks as it deformed or maybe starting to glow from the contact point and radiating from there rather than all at once.

I was also thinking of this while watching the video. I think they want to eventually implement that into the simulation, but not yet in Alpha 7.

[WitheHole18]

Wow the video it's fantastic ..but I did not understand the last part...
However Alpha 7 should be out of this passage in early July...
I am very curious to see Earth vs. Earth...
It would be nice if you could also try the preview, but I think it's better to wait.

[Dan Dixon]

Why does the Moon turn into a Sun when it touches the ground? o.o

This is a bug or hack, actually where once so much energy is released the whole planet or moon goes molten. In this example, the moon shouldn't do this so quickly. We're working on it.

[dechireur77]

All worlds will have access to the alpha7 when she will go out? ?
we can buy on steam(alpha7)?

[Xriqxa]

She? 

No, only testers will have Alpha 7. The initial release, Open Alpha, will be available to everyone first on this website and then later steam.

[dechireur77]

Thank you for your answer, shall owe we him(her,it) bought to be able to play it? "Sorry I am one can bad in English"

[DiamondMiner10]

That looks awesome.

[gabriel.dac]

So far no one answered me what would happen if the Moon falls on your head

[Cosmos]

So far no one answered me what would happen if the Moon falls on your head

97878 billion megatons of energy released

Crater Diameter: 6250.0 km
Crater Depth: 4.1 km

The Earth's ocean would boil away.

[gabriel.dac]

So far no one answered me what would happen if the Moon falls on your head

97878 billion megatons of energy released

Crater Diameter: 6250.0 km
Crater Depth: 4.1 km

The Earth's ocean would boil away.

You didn't answer my question at all

[Cosmos]

So far no one answered me what would happen if the Moon falls on your head

97878 billion megatons of energy released

Crater Diameter: 6250.0 km
Crater Depth: 4.1 km

The Earth's ocean would boil away.

You didn't answer my question at all

Well.

[Greenleaf]

So far no one answered me what would happen if the Moon falls on your head

97878 billion megatons of energy released

Crater Diameter: 6250.0 km
Crater Depth: 4.1 km

The Earth's ocean would boil away.

Its actually a lot worse.
Perhaps you used something like http://www.purdue.edu/impactearth/ which essentially only works with small impacts in which only the impact velocity is used and the potential energy is ignored. If we include potential energy we get this case:

The moon and earth both being non rotating spheres with assumed constant density and their position being so they just touch before impact and the moon having a relative velocity of 12km/s directly towards Earths center, a quick estimation (hopefully without too many stupid errors) gives...

initial state:
kinetic energy_1 = 0.5*7.35E+22kg*12000^2m/s = 5.3E+30 joule
potential energy_1 = -(6.67E-11N(m/kg)^2*5.97E+24kg*7.35E+22kg)/8108000m = -3E+30 joule
mechanical energy = kin+pot = 2.3E+30 joule

The total mass of the combined object after collision (ignoring fragmentation) is then 5.97E+24 kg + 7.35E+22 kg = 6.05E+24 kg.

With conservation of momentum, the velocity of the combined body (assuming inelastic collision) after collision is then 7.35E+22kg*12000m/s / (6.05E+24kg) = 146m/s

final state:
kinetic energy_2 = 0.5*6.05E+24kg*146^2 m/s = 6.445E+28 joule
potential energy_2 =  -(3/5)*(6.67E-11N(m/kg)^2 * 6.05E+24^2 kg) / 6425000m =  -2.27E+32 joule
mechanical energy = kin+pot = -2.3E+32 joule

mechanical energy decrease = 2.32E+32 joule = 5.5E+13 giga ton TNT

assuming, wrongly, that the combined body is entirely made up of water this energy could heat it about 8300 degrees K including it going from liquid to gas, but assuming constant heat capacity.

Lots of assumptions made and energy lost to fragments and potential energy not totally realized due to non uniform densities. Also energy would not be evenly distributed, and there should stil be waves, carrying energy, passing through the remaining material long after the collision. The general point stands: moon should really not fall like that! It would give a whole lot of evaporating stuff and it would be very sad :-/

Its not impossible that I missed a digit somewhere, so consider this a back-of-the-envelope calculation.

[gabriel.dac]

Guys, I was referring to the simulation. I asked what would be seen if, in the simulation, the moon fell on the  camera view. What would be seen.

I am actually quite surprised no one got it.

[WitheHole18]

Probably would notice a depression in the ground and lava.
While the borders you would notice a lot of dust and fragments fall rise up in the air.
However, it would be better a video representation of a very theoretical explanation...

[Dan Dixon]

Guys, I was referring to the simulation...

Seems fair to point out that Thomas answered your question with great detail (if not what you intended), and you didn't even acknowledge his efforts.

[pac0master]

So far no one answered me what would happen if the Moon falls on your head

You die
The End.

:V

But in the game, The moon just get closer and closer and look very blur.  as it impact, the camera will pass through it and you need to get off the camera view.

Here is my attempt

http://imgur.com/a/0UtkC/embed

[blotz]

Thomas = Greenleaf right?

[tuto99]

Guys, I was referring to the simulation. I asked what would be seen if, in the simulation, the moon fell on the  camera view. What would be seen.

I am actually quite surprised no one got it.

Then you could've asked, what would happen if the moon landed right where the camera was at? Don't be a jerk about it.

[pac0master]

Well I posted a few pictures, in my reply above. :3 

[PrimeMinisterTom]

She? 

Masculine and feminine grammar contexts exist in French. It also applies to things with certain endings.

Its actually a lot worse.
Perhaps you used something like http://www.purdue.edu/impactearth/ which essentially only works with small impacts in which only the impact velocity is used and the potential energy is ignored. If we include potential energy we get this case:

The moon and earth both being non rotating spheres with assumed constant density and their position being so they just touch before impact and the moon having a relative velocity of 12km/s directly towards Earths center, a quick estimation (hopefully without too many stupid errors) gives...

initial state:
kinetic energy_1 = 0.5*7.35E+22kg*12000^2m/s = 5.3E+30 joule
potential energy_1 = -(6.67E-11N(m/kg)^2*5.97E+24kg*7.35E+22kg)/8108000m = -3E+30 joule
mechanical energy = kin+pot = 2.3E+30 joule

The total mass of the combined object after collision (ignoring fragmentation) is then 5.97E+24 kg + 7.35E+22 kg = 6.05E+24 kg.

With conservation of momentum, the velocity of the combined body (assuming inelastic collision) after collision is then 7.35E+22kg*12000m/s / (6.05E+24kg) = 146m/s

final state:
kinetic energy_2 = 0.5*6.05E+24kg*146^2 m/s = 6.445E+28 joule
potential energy_2 =  -(3/5)*(6.67E-11N(m/kg)^2 * 6.05E+24^2 kg) / 6425000m =  -2.27E+32 joule
mechanical energy = kin+pot = -2.3E+32 joule

mechanical energy decrease = 2.32E+32 joule = 5.5E+13 giga ton TNT

assuming, wrongly, that the combined body is entirely made up of water this energy could heat it about 8300 degrees K including it going from liquid to gas, but assuming constant heat capacity.

Lots of assumptions made and energy lost to fragments and potential energy not totally realized due to non uniform densities. Also energy would not be evenly distributed, and there should stil be waves, carrying energy, passing through the remaining material long after the collision. The general point stands: moon should really not fall like that! It would give a whole lot of evaporating stuff and it would be very sad :-/

Its not impossible that I missed a digit somewhere, so consider this a back-of-the-envelope calculation.

o.o No words.