Vaporizing Phobos?

Isil`Zha · Post by **Isil`Zha** » 2003-03-15 01:33am

What would be the energy required to vaporize Mars's satellite, Phobos, from a blast orginating from within its core? I've tried searching for the equations or calculators on vaproization but I can't find any. (In TJ)

Thanks.

Enlightenment · Post by **Enlightenment** » 2003-03-15 01:42am

There's a vaporization calculator on the main site.

http://www.stardestroyer.net/Empire/Sci ... roids.html

For the purposes of an order of magnitude guess, Phobos is probably closest to hard granite.

Isil`Zha · Post by **Isil`Zha** » 2003-03-15 01:55am

EDIT

Whoops, different units of measurement.

Isil`Zha · Post by **Isil`Zha** » 2003-03-15 02:07am

I'm assuming the tons are metric tons on that calculator?

Enlightenment · Post by **Enlightenment** » 2003-03-15 02:23am

Isil`Zha wrote:I'm assuming the tons are metric tons on that calculator?

I didn't write it but I'd assume so.

Durandal · Post by **Durandal** » 2003-03-15 03:54am

Data suggest that Phobos has similar composition to a C-type asteroid, which has similar composition to carbonaceous chondrite meteorites. These meteorites are generally made up of some combination of Iron (Fe), Silicon (Si), Magnesium (Mg), Calcium (Ca) and Aluminum (Al). Iron is a pretty decent representation of these elements (though their melting points vary anywhere from the 1000C to 3000C range), so we can use it as a rough approximation.

Iron has a melting point of ~1800 C, and a vaporization point of ~3000 C. It has a specific heat of 600 J/kg*K, a latent heat of fusion of 300 kJ/kg and latent heat of vaporization of 6 MJ/kg. Phobos' mass is about 1E16 kg.

We'll ignore the fact that the lack of pressure in space will aid the expansion, and thus lower energy requirements. We'll assume a starting temperature of 150 K, just because. This pegs melting energy at 1.3E22 J and vaporization energy at 6.7E22 J, for a total of 8E22 J. That's roughly 19 teratons of TNT.

Isil`Zha · Post by **Isil`Zha** » 2003-03-15 11:16pm

Thanks.

Post by **Darth Wong** » 2003-03-15 11:20pm

How big is Phobos? If I guess 13 km diameter spherical and plug that into my calculator, I get roughly 16,000 gigatons for nickel-iron and around 8,500 for hard granite. Hell, it takes 700 gigatons even if it's made out of ice.

But if you don't completely vapourize it, it's a whole different story. Fragmentation energy is orders of magnitude lower.

Durandal · Post by **Durandal** » 2003-03-15 11:27pm

Phobos is roughly 22 km in diameter.

Awesome site with information on all nine planet and their moons

By the way, Mike, you seem to have access to the thermal properties of granite. A year or two back, I had a Hell of a time finding that information and never did. Just out of curiosity, what are they?

The Dark · Post by **The Dark** » 2003-03-15 11:27pm

22km diameter, according to the Hawai'i Institute of Geophysics and Planetology. That means 40,900 gigatons to vaporize, assuming granite. 79,700 for iron-nickel, and 3,390 for ice. That's a pretty good amount of energy.

Isil`Zha · Post by **Isil`Zha** » 2003-03-16 03:07am

Hmmm, as far as I could tell from where this is coming from Phobos was pretty much completely vaporized, I'll have to watch it again to see for sure, but I'm going to check fragmentation energy too... And actually that site is where I was getting my info off Phobos from.. and from what information I can get about it's make-up, I'd lean more towards using granite as the base.

Admiral Valdemar · Post by **Admiral Valdemar** » 2003-03-16 09:37am

I think it's pretty safe to say that Jehuty will take more punishment than a Bolo now even using these low end calcs.

Post by **Darth Wong** » 2003-03-16 01:13pm

By the way, one interesting factoid about AOTC is that ILM modelled one of the big asteroids being shattered by Jango's seismic charges on Phobos.

Admiral Valdemar · Post by **Admiral Valdemar** » 2003-03-16 02:44pm

Darth Wong wrote:By the way, one interesting factoid about AOTC is that ILM modelled one of the big asteroids being shattered by Jango's seismic charges on Phobos.

I can just imagine a tiny seismic charge ripping through Phobos like that, some serious firepower.

Isil'Zha: What exactly do they use to blow Phobos up in ZOE2 anyway? It obviously isn't Jehuty since it survives and only creates 22.3GT from self-destructing.

Isil`Zha · Post by **Isil`Zha** » 2003-03-16 10:37pm

Admiral Valdemar wrote:
Darth Wong wrote:By the way, one interesting factoid about AOTC is that ILM modelled one of the big asteroids being shattered by Jango's seismic charges on Phobos.
Isil'Zha: What exactly do they use to blow Phobos up in ZOE2 anyway? It obviously isn't Jehuty since it survives and only creates 22.3GT from self-destructing.

Well since you obviously don't mind spoilers.. (I'm not giving you them all though

) They used Anubis+Aumaan... it's how the final battle ends. So yes, one of them does self-destruct and we do get a *massive* explosion. However, it was used to stop Aumaan, which caused Aumaan to detonate too since it had already been activated and would've *SPOILER DELETED, WAIT UNTIL YOU PLAY THROUGH IT

* Now, they literally state earlier that Aumaan is "One million times more powerful than Anubis" but I'm not about to use *that* number... (I must add that N-Jehuty is probably around 50x more powerful than Anubis.. took me all of 13 seconds to take down Anubis with it)