Reel Physics: GI Joe Retaliation - Tungsten Rod Drop

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GI Joe Retaliation - Tungsten Rod Drop

Jason and Colby shed some light on the destruction that Cobra has brought to London.

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I have to admit, I got lost in this one. Too many megajoules, pounds of TNT and other units flipping around and comparing in different directions. Can you rephrase it entirely in terms of "big badda-booms?"

Hah, so the "weapon" would be even less useful then my friends and I thought it would be after seeing that. And we already weren't expecting it to be anywhere near what's shown.

Great episode as always guys :)

I was more surprised about how few fu**'s was given by the main characters about the complete destruction of London. Those guys where cold.

That Queen/Cobra Commander duet was quite possibly the most beautiful thing I have ever seen in my life. Art has finally reached an apex...

Anyway, that was the most predictable episode so far. It was so obviously not realist, yet you still made it fun and informative. I applaud you good sirs!

Good episode as always, even thou the math is something I don't understand, as always
I totally cracked at the I Want It All part xD

The episode was fine and all, but for the record, if you replace the last six minutes with just a loop of the Cobra Commander/Queen mashup, I still would have watched it.

Also, I feel like the big surprise here isn't that the movie was reel physics (which probably surprised no one), but that the US apparently actually proposed something like this in the 50's. Someone actually thought that dropping tungsten rods on people from space was a reasonable plan of attack.

Well it looked like a doomsday weapon, but in reality...

puts on sunglasses

...Rod saved the Queen

Am I the only one here who knows that you can't drop a rod from orbit. If The rod would just stay near the platform it was released from and not fall to the ground unless it has an engine to burn retrograde.

<Been playing too much Kerbal Space Program.

For those interested in the level of actual bombing across London years ago: http://www.bombsight.org/#11/51.4923/-0.1452

RobotDinosaur:
The episode was fine and all, but for the record, if you replace the last six minutes with just a loop of the Cobra Commander/Queen mashup, I still would have watched it.

Also, I feel like the big surprise here isn't that the movie was reel physics (which probably surprised no one), but that the US apparently actually proposed something like this in the 50's. Someone actually thought that dropping tungsten rods on people from space was a reasonable plan of attack.

the US also build nuclear bazookas in the 50s.

and the queen/Cobra Commander thing was indeed great, everything is better with queen

RobotDinosaur:

Also, I feel like the big surprise here isn't that the movie was reel physics (which probably surprised no one), but that the US apparently actually proposed something like this in the 50's. Someone actually thought that dropping tungsten rods on people from space was a reasonable plan of attack.

To be fair, the US currently thinks that dropping anti-tank missiles on random people it never even identifies, in nations it isn't even at war with, is a reasonable plan of attack. The only reason we probably don't use kinetic strikes instead of drone strikes is because the technology is currently nowhere near good enough to actually hit an individual (or at least hit with the same accuracy as a hellfire missile) from orbit. But just give it time, the way the US is going, I have to think rod-from-God kill-sats are inevitable.

But yeah, just dropping a rod, even from orbit, isn't enough. You either need a powerful booster-rocket to accelerate it or it needs to be fired off by some sort of mass-driver or railgun (something else that the US military is getting closer and closer to making viable). From a purely military point of view, kinetic strikes do have a lot of advantages. You can dial their damage output with the size of the rod and how much you accelerate it, to provide everything from a bunker-buster to the equivalent of a tactical nuclear strike (without any sort of radioactive fallout). Still, I can't say I'm looking forward to when every nation with a space-program has kill-sats hanging over everyone else's heads.

Having watched the whole thing, I can safely say I have no idea what the final verdict was. Like I get that the movie went overboard, but by how far? What would the destruction have been? Are we talking a hole the size of a car or a city block?

Ignoring the fact that the rod would need some kind of initial propulsion (presumably a rocket motor, since a railgun would be insanely expensive and complicate the process of keeping the mother satellite in a stable orbit after each shot) Thor is still viable, but it would be insanely expensive to loft a piece of tungsten that size. I'm also really surprised at how small the impact shown actually is - I was anticipating at least five or six kilotons at least.

Honestly, I see more viability in the Thor concept as a precision weapons system than a WMD, which the result here reinforces. Conventional nuclear warheads are much more efficient/cost-effective at knocking down large portions of city (and even those are, surprisingly, less powerful than reputed). If the accuracy could be enhanced to a certain level it would be great for taking out small, heavily fortified positions with smaller projectiles, since it's basically the ultimate penetrator, but not as a giant doomsday machine.

EDIT: I just did a little wiki-crawling and, assuming we're using US tons (1 ton=2,000 pounds) a Saturn V could put 14 9-ton tungsten rods into low orbit. Granted, that's still an insane amount of money and nobody has a lifter with the payload of the Saturn platform right now, but it's still less expensive than I'd assume. Of course it's still somewhat ineffective as a weapon of mass destruction, but it's not as outlandish as one might think.

Hitchmeister:
I have to admit, I got lost in this one. Too many megajoules, pounds of TNT and other units flipping around and comparing in different directions. Can you rephrase it entirely in terms of "big badda-booms?"

what I gathered was...
energy required to make the least part of the scene happen: ~900mJ
extremely optimistic energy output of the weapon described: ~380mJ

Pretty much what I expected.

You didn't answer all of your questions... and now I'm just left unsatisfied...

I wanted to know how much damage it would actually cause :(

Edit:

Also... the episode covered this whole thing, and you never mentioned that the abort button was also the self destruct switch?

Why would Cobra even put a self destruct system in?!

What are they afraid of? The system being used on their own nation?

They don't have a nation.

it's funny, because it is a viable weapons platform it just isn't a super-weapon
it would level a city block fairly well, it just needs a bigger rod..

poor super-weapon, it has a rod complex :(

I really like that they kept looping that destruction scene of London. I could watch CG graphics like that all day.
It's the same reason I bought and keep watching the start of 2012. I love when films show everything going to hell in a pretty convincing way ^_^

i still like the idea of a giant rock mass driver on the moon if you want to go doomsday. it has that whole 60's supervillian vibe about it.

ReelPhysics:
GI Joe Retaliation - Tungsten Rod Drop

Jason and Colby shed some light on the destruction that Cobra has brought to London.

Watch Video

First a correction:
You keep writing mJ and saying megajoule. The correct way of writing megajoule i MJ (capital M and J) otherwise you are giving the result in millijoule (1/1000 Joule). As a physics teacher this irks me quite a lot.

Now back to topic.
The damage a rod-from-the-gods (as they are also called) will do is very much comparable with current bunker-buster weapons/cruise missiles. That is it will penetrate several meters of rock/concrete and doing quite a lot of damage in the process but not near enough to level a city block.

Hey Everyone,
This week is another viewer request. We had fun covering this one, especially finding out it was based on a real military theoretical project of a similar name. It was interesting to say the least.

Check out GI Joe Retaliation and be sure to look for the Queen/Cobra Commander remix!

As always, if you like the show, please share it out on your Facebook feed... like it... tweet it... post it... whatever it is you do in your little internet bubble... please tell everyone about the show so we can help build our audience.

Thanks again!
Jason Dean
REEL PHYSICS

You mentioned that you were using low earth orbit. What if you had used high earth orbit instead? And are there any materials that would produce a more destructive result?

This weapon would have been better in a bond film :(.

Sad that it got wasted. I like GI Joe but I feel it would have been cooler for bond.

The gal in the background is fantastic in the outtakes btw.

wombat_of_war:
i still like the idea of a giant rock mass driver on the moon if you want to go doomsday. it has that whole 60's supervillian vibe about it.

You...I like you.

Hopefully something like that will be in Planetary Annihilation :o.

GREAT, AWESOME rap from Cobra Commander!!!
If this was on YouTube you guys 'd get millions of hits.

Really made me lol, thanks guys!!!!

Who was that stoned-sounding girl at the end?!?!

...and does she always talk like that?

Am I wrong to think that the force of impact from a rod-from-the-gods would spread outwards in the form of a wave rather than a huge circle, all being raised at once? Meaning that to lift that river, you don't need anywhere near enough force to lift it all at once, but rather only enough energy for a part of it, which then propagates through it.

This still ignores all the land-area around it though.
I suppose you could approximate that area by treating it as water as well, making London a large lake instead, but then the impact need to deliver a lot of energy again.

Now I know more things. *runs off to do terrorist stuff*

For comparison, the Halifax explosion ruined all the buildings for 26 km (16 Miles). Further, the water surged as high as 18 m (60 ft). This seems similar to the clip. The estimated explosion size was 2900 tons of TNT. They estimated the energy of the rod at 78.31 tons of tnt. Which is much smaller.

Great episode. This is quickly becoming one of my favourite shows on The Escapist. I love the added production value to the comedy bits. Things like green screening yourselves in, the Speed skit you did, and in this case the Cobra Commander/Queen mashup. Good times.

I have a question. How fast would the tungsten rod have to travel to meet the energy requirements? Or how big would the rod have to be at the speed given to produce the energy needed?

That girl at the end who wanted to play parcheesi: For the love of all that's good and holy, please tell me it was one of your moms.

Mouse_Crouse:
Having watched the whole thing, I can safely say I have no idea what the final verdict was. Like I get that the movie went overboard, but by how far? What would the destruction have been? Are we talking a hole the size of a car or a city block?

Then you obviously didn't watch the whole thing.

One day, Colby will be on the left, Jason on the right, and our minds won't be able to cope...

When you mentioned the Clash over the reaction shot from London, my response was "London Calling"?

Eleuthera:
Hah, so the "weapon" would be even less useful then my friends and I thought it would be after seeing that. And we already weren't expecting it to be anywhere near what's shown.

Great episode as always guys :)

It's an actual weapon design from the cold war, actually, to the point it was specifically cited in the discussions that led to the treaties banning orbital weapons.

The dimensions, details and effects got Michael Bay'd, though, obviously. The real designs involved a bit more driving mass, primarily, and were intended as more precise bunker-buster type weapons. No sillier than the fistfights or gunfights in the movie, though.

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