For all those who hate A:CM

[SM]

I think we both know the answer to that.

[Local Trouble]

[Predator@Alien]

So for the air density, we suppose that the temperature is acceptable, that is to say an air mass of about 1.25 kg / m3. As there is almost not air movement the pressure is static. All of this pressure becomes dynamic once the airlock has opened, so we go from a pressure of 1 atmosphere to 0 (for vacuum).
The formula for dynamic pressure: 0.5 x density x speed2.
So for the speed: √ (2 x pressure (Pa) / density) = √ (2 x 101500 / 1.25) = 403 km / s = 1450 km / h.

101500 is in Pascal, which is roughly equivalent to the air density of 1 Bar.

And for the evacuation speed, the airlock surface being around 25m2 (5x5), we therefore lose VxS (Speed ​​x Surface) = 403 km / s x 25 m2 = 10,000 m3 / second.

[SM]

Your airlock dimensions are way too big, but thanks.

[Predator@Alien]

So what are the dimensions ? Visually I think I'm not really far from the reality 

[SM]

I reckon about 3m x 3m or so.

No idea how much difference that would make without working it out.

[Predator@Alien]

It makes a huge difference indeed, so there will be a loss of 3627 m3 / s.

The airlock is completely open during about 50 seconds. So to not be empty until the end, the bay should have these dimensions : 150 m X 200 m X 6 M. So yes it's possible.

But we know that SF is not science and a lot of problems can be noted. The proportions of LV-426 are completely impossible, there is no way to arrange that. However Alien is not non-canon with itself... So for me there is no problem to accept that Bishop is just a machine build by humans and lile every machine build by humans, there are some gaps. With imagination we can find a lot of reason to make it consistent with Aliens. For me I'll just say that he overevalued the power of the explosion. And as Local Trouble quoted, why no trying to find scientific talk to explain that, like we do for everything else ? For me it's no problem ^^'

[SM]

Let's pretend Bishop got both the yield and blast radius wrong despite the film showing us he didn't.  Say it's only 3 megatons.

The colony is still vapourised.

[Local Trouble]

This is a fun little tool...

https://nuclearsecrecy.com/nukemap/

[SM]

Indeed.

[Xiggz456]

My theory was that perhaps the atmospheric processor had fail safes in place to minimize damage to the colony in the event of an overload. These fail safes would direct the majority of the energy skyward. But between ACM, Out of the Shadows, and Resistance/Rescue, nukes aren't near as devastating in the Aliens universe as they are in reality.

[SM]

There are failsafes.  They failed.  "The crash caused too much damage".

[Local Trouble]

Bishop works for the ECA and he's an android.  Chances are he's familiar enough with atmosphere processors to give a reliable estimate of the explosive yield if one of them should overload.

[SM]

I'm not sure a robot would offer a reliable estimate if he was unable to offer a reliable estimate.

[Local Trouble]

Yeah, he'd probably offer something closer to, "I don't know how big the explosion will be, but it should be big enough that we won't want to be here when it happens."