# Superman Returns Phyics *SPOILER*

1. Jun 29, 2006

### Quaoar

OK, I'm giving away the ending, so don't say I didn't warn you...

At the end, Superman lifts Luthor's new landmass into space. I did some rough hand calculations to figure out how much energy Superman had to use to lift the island into space. Judging from the scale presented in the movie, I'm estimating the island was roughly 5 miles in radius, 5 miles thick. This yields a volume of pi * 5^3 ~ 400 cubic miles = 1.7e12 cubic meters. Given that the island appears to be made of a material similar to Quartz, with a density of 2600 kg/m^3, this gives us a total mass of 4.3e15 kg. Escape velocity at the Earth's surface is 11,000 m/s.

Assuming that Superman accelerated the object to not much more than escape velocity, that gives us 1/2 * 4.3e15 kg * (11000 m/s)^2 = 2.6e23 joules. Hiroshima was 6e13 joules. So this act is equivalent to exploding about 4.4 BILLION Hiroshima bombs!

Anyhow, just thought I should share... :)

Edit: Whoops, forgot to square the velocity.

Last edited: Jun 29, 2006
2. Jun 29, 2006

### Kurdt

Staff Emeritus
I guess thats why hes called superman :)

3. Jun 29, 2006

### moose

On some tv channel, I think national geographic or something, they will have a special on the crappy physics in that movie and how some of the people he "saves" would be far more hurt by him catching them the way he does than them falling to the ground and stuff like that. I can't wait to watch it...

4. Jun 29, 2006

### moose

Last edited: Jun 29, 2006
5. Jun 29, 2006

### Kurdt

Staff Emeritus
Supermans energy source is the sun of krypton not awesomeness I believe. This is true in the old Reeve films however in the New adventures and Smallville it is in fact our own sun that is the source of his power.

Anyhoo...

6. Jun 29, 2006

### Quaoar

Oops. Fixed.

7. Jun 29, 2006

### Quaoar

This is still true in the movie, though the amount of energy he expends would take a LOT of sunbathing to collect...

8. Jun 29, 2006

### Kurdt

Staff Emeritus
Yes i was thinking that.

9. Jun 29, 2006

### tony873004

If he gave it Earth escape velocity, unless he's planning on visiting this landmass in 1/2 of its solar orbit to give it a perihelion boost, he just inserted a a huge asteroid into an Earth-crossing orbit. It would definately make the list of PHAs (potentially hazardous objects).

As long as he's immortal, and as long as he doesn't plan on abandoning Earth again (that is the theme of the movie, right? He returns after an absense) we'll be ok.

BTW. Wouldn't he be more likely to punch a hole through the island, rather than lift it? I can't lift a pillow with the tip of a pin.

I can't wait to see the movie.

10. Jun 29, 2006

### Quaoar

Well, the island kinda crumbles a bit as he lifts it, but not as much as you'd imagine. It's not an Earthly material though, so it might be extra strong.

11. Jul 1, 2006

### tony873004

Sorry, I forgot to take that into account :tongue2:

12. Jul 5, 2006

### Mallignamius

Isn't a large enough portion Earth-made, so that it wouldn't have the necessary integrity?

13. Jul 5, 2006

### BoTemp

The raw material must come from Earth, but it's a Kryptonian crystal, so it's structure would be extra-strong, nigh indestructible. But he wouldn't have to accelerate it to escape velocity from the surface, as he lifts it up into orbit first. Same amount of total energy expended on his part, but he would be able to spread out it's expenditure a bit.

*Another Spoiler*: My problem with the movie came at the end when Kitty dropped the crystals onto the island. They'd quite likely fall into the ocean, no? Maybe not necessarily. But if they did, that would just make the problem a lot worse.

14. Jul 5, 2006

### Quaoar

He appears to only lift the island a couple hundred miles above the Earth's surface before letting go (He starts reentry shortly afterwards). The escape velocity difference between being on Earth's surface and a couple hundred miles away from Earth's surface is neglible, so we can treat it as if he expended all the energy at the surface.

Well, the crystals are on the island Superman gets rid of. Some chunks fall off, but I guess we are to assume that the crystals are able to hang on for the ride...

15. Mar 20, 2010

### Newai

I hate to necropost, but this is the most appropriate thread for the question that's been bugging me.

Luthor said something to the effect that crystals mimic the properties of their environment. I don't see anything at Wikipedia that supports this. Perhaps license taken by the writers?