Starfleet Jedi

http://www.imsdb.com/scripts/Star-Wars-The-Empire-Strikes-Back.html wrote: VEERS: My lord, the fleet has moves out of light-speed. Com-Scan has detected an energy field protecting an area around the sixth planet of the Hoth system. The field is strong enough to deflect any bombardment.

The shield the Rebel Alliance used on Hoth was strong enough to shrug off any bombardment, but for that to be true then the Empire would have to lack the firepower to cause a localized planet quake that they would think to be powerful enough to shake the base to the ground.

http://www.imsdb.com/scripts/Star-Wars-The-Empire-Strikes-Back.html wrote: LEIA: All troop carriers will assemble at the north entrance. The heavy transport ships will leave as soon as they're loaded. Only two fighter escorts per ship. The energy shield can only be opened for a short time, so you'll have to stay very close to your transports.

Ships trying to land or take off could not pass through it. This would mean that the landing party sent to attack the Rebel base would land near the edge of the shield.

Star Wars The New Essential Guide To Weapons & Technology ISBN 978-0-345-44903-0 Page: 113 wrote: The Kuat Drive Yards DSS-02 planetary shield generator deployed by the Alliance on Hoth, for instance, covered an area about fifty kilometers in diameter. Like many planetary shields, the DSS-02 had to be lowered whenever the Alliance wished to fire its ion cannon or send an escaping transport into space. Such shields also require an inordinate amount of energy and take nearly half an hour to activate.

This is the only data I know of that details the size of the area the shield on Hoth covered, and the diameter seems reasonable given what we see in the movies.

How could someone use this data to best calculate the amount of fire power an Imperial Star destroyer can bring to bear?

Like, the highest yield per shot figure acceptable before the canopy's range isn't sufficient to protect the base.

To me, it doesn't look like the base used anything fancy to reinforce rock or ice. Therefore, you're most likely looking at any kind of blast in the ground capable of starting threatening the base's natural structure; the yield per shot is above that.

Actually it could be quite easy. Just look for data about earthquakes and the levels of damage noticed on various structures. Look notably for anything that would significantly break rock and ice.
With the minimal amount of force needed at the target's location, obtaining the right magnitude at ground zero, based on distance to the target, will require some calculations but I don't think it will be that hard.

However, this calculation is only acceptable if the Rebels thought that without the shield, the Empire would simply reduce the base to smithereens. The Imperials clearly had other plans in mind so their opinion on the tactical abilities of the shield are totally based on their capacity to have a direct shot at key points, like the generator, ground defenses and perhaps entrance points.

I would say that before going into any complicated data research and calculation, try to avoid running into a sheer speculation and prove first that the rebels really considered that the shield would prevent the Empire from blasting them to bits and simply not prevent it from hitting key targets.

With fact Iron cannon main reason none Star Destroyers were able fire range. Suggestion Shield not strongth provide protect against the ISD. Shield seem storng protect against Tie bomber other weaker form of bombers. Fact deploy ground force suggestion shield also strong enough provide protect against artellery weapons. Suggestion Hoth shield design protect more against fighters and artellory and entirely useless coming protect big capitil starship.

Jasonb wrote:With fact Iron cannon main reason none Star Destroyers were able fire range. Suggestion Shield not strongth provide protect against the ISD. Shield seem storng protect against Tie bomber other weaker form of bombers. Fact deploy ground force suggestion shield also strong enough provide protect against artellery weapons. Suggestion Hoth shield design protect more against fighters and artellory and entirely useless coming protect big capitil starship.

One of the Imperial Officers stated that the shield was "capable of withstanding any bombardment", so it can repel firepower from at least several ISD's and one SSD.

"Any bombardment" was in sense of Vader's fleet.

Mr. Oragahn wrote: Like, the highest yield per shot figure acceptable before the canopy's range isn't sufficient to protect the base.

The shaking caused by the bombardment would destroy the rebel base before the crater would be large enough reach the base. The problem is I don't know how to calculate the earthquake like shaking caused by the sudden input of energy. I'm not sure how you calculate a weapon like Tall Boy or Grand Slam.

I also don't know how to calculate crater size, and it seems like every nuclear effects calculator I find only cares about the fireball and other surface effects. This is the only crater calculator i have found, but I can't get it to work.

http://keith.aa.washington.edu/craterdata/

Mr. Oragahn wrote: Actually it could be quite easy. Just look for data about earthquakes and the levels of damage noticed on various structures. Look notably for anything that would significantly break rock and ice.
With the minimal amount of force needed at the target's location, obtaining the right magnitude at ground zero, based on distance to the target, will require some calculations but I don't think it will be that hard.

If these are to be believed: http://skywalker.cochise.edu/wellerr/st ... /paper.htm
http://earthquake.usgs.gov/learn/topics/mag_vs_int.php 6.0 earthquakes repeatedly hitting the rebel base should be expected to bring down most anything

http://www.projectrho.com/public_html/r ... Boom_Table

7.0 on the Richter scale is 2.0x10^15 or about 477 kt

8.0 on the Richter scale is 6.3x10^16 or about 15 Mt

9.0 on the Richter scale is 2.5x10^18 or about 477 Mt

9.5 on the Richter scale is 1.1x10^19 or about 3 Gt

Mr. Oragahn wrote: However, this calculation is only acceptable if the Rebels thought that without the shield, the Empire would simply reduce the base to smithereens. The Imperials clearly had other plans in mind so their opinion on the tactical abilities of the shield are totally based on their capacity to have a direct shot at key points, like the generator, ground defenses and perhaps entrance points.

The R.A. could only hunker down or run. They would need a defense that could deflect any bombardment the Empire could throw at them.

I'm not sure what relevance the Rebel Alliance's thought on the shield are? All that matter is what the Empire stated about the shield.

Mr. Oragahn wrote: I would say that before going into any complicated data research and calculation, try to avoid running into a sheer speculation and prove first that the rebels really considered that the shield would prevent the Empire from blasting them to bits and simply not prevent it from hitting key targets.

Veer's statement and the lack of correction by others is proof the shield could hold off the bombardment by the Empire's weapons, or are you saying that the empieal forces did not know what their weapons could do?

There's also the difference between an impact or violent cratering, more precisely, and the equivalent energetic yield of an earthquake.
The energies they give for earthquakes often seem to be the total amount of energy delivered by the earthquake, while it's a repeating phenomenon rather than a one shot explosion.

Mr. Oragahn wrote: There's also the difference between an impact or violent cratering, more precisely, and the equivalent energetic yield of an earthquake.
The energies they give for earthquakes often seem to be the total amount of energy delivered by the earthquake, while it's a repeating phenomenon rather than a one shot explosion.

An earthquake is a singular event.

The bomb used to destroy the Oklahoma Federal building was about a 3.0. That was only the equivalent of about 5000 pounds of TNT that exploded a few feet off the ground.

Earthquake bombs are what you use to destroy bases that have defenses like those at Hoth. It's how we do it in the real world.
http://en.wikipedia.org/wiki/Earthquake_bomb

No no, earthquakes have several ripples as far as I know, while the explosion you think of has one main shockwave and anything behind is quite residual.
Let's compare seismic activity resulting from a nuclear detonation and from earthquakes perhaps?

Yeah, earthquakes ripple. I know this from firsthand experience.

I have to ask if Lucky's intent in the OP is to use the Hoth shield to determine an upper limit for SW planetary shields in general or just to figure out what the maximum shield diameter for Hoth alone to determine what SD firepower might be since they chose not to attack the unprotected land around the shield and generate seismic quakes to damage or destroy the Rebel base.

Otherwise, just read the Base Delta Zero thread, starting here on page two and onward, which discusses the probable size of the Endor shield. That shield is much larger than Hoth's since it had to completely cover the spherical, 160 km Death Star.
-Mike

Mike DiCenso wrote: I have to ask if Lucky's intent in the OP is to use the Hoth shield to determine an upper limit for SW planetary shields in general or just to figure out what the maximum shield diameter for Hoth alone to determine what SD firepower might be since they chose not to attack the unprotected land around the shield and generate seismic quakes to damage or destroy the Rebel base.

Otherwise, just read the Base Delta Zero thread, starting here on page two and onward, which discusses the probable size of the Endor shield. That shield is much larger than Hoth's since it had to completely cover the spherical, 160 km Death Star.
-Mike

1) I already provided the official diameter of the Hoth shield given in the New Essential guide to Weapons and Technology. I'm not aware of any other radiuses or diameters for said shield being given in other sources, and the given diameter seems reasonable.

2) I already supplied the quotes from from the movie that tell us that no matter how many times the fleet fired they would not be able to destroy the rebel base on Hoth.

3) Because blaster bolts, laser bolts, and turbolaser bolts are explosive, I see no reason to not treat them as bombs or shells. We also see T.I.E. bombers drop glowy things that cause an asteroid to shake as if it is having earthquakes.

5) I have supplied real life examples of weapons that are referred to as earthquake bombs. They work by exploding underground and causing a localized earthquake. They are used when bombardment from above do to fortifications is not practical. Simply put, creating a crater large enough to reach the rebel base is far more fire power then is needed to destroy the base. I do not think that saying real life weapons that have been both designed and used do not work as they have been show to work in practice is a good idea. Barnes Wallis was a brilliant engineer and inventor.
http://en.wikipedia.org/wiki/Barnes_Wallis#Bomb_design

6) I am not sure how you calculate a crater or how one calculates the effects of an earthquake bomb. Everything I've been able to understand has focused on the above ground effects making them useless to this calculation. To this end I am asking for help or for some else to do the math.

7) The Death Star is never stated to have a shield of is own, and is a special case.

Khas wrote: Yeah, earthquakes ripple. I know this from firsthand experience.

Those ripples are called blast waves in a bomb.
http://en.wikipedia.org/wiki/Blast_wave

An earthquake is simply a sudden release of energy in the ground. Powerful bombs cause effects similar to earthquakes. Because powerful bombs cause effects similar to earthquakes they are detected on devices intended to measure earthquakes. The bomb that destroyed the Oklahoma City Federal building registered as a 3.0 earthquake.

Take a look at a 5000 pound ANFO bomb
http://www.youtube.com/watch?v=vYKbBavXriY

http://en.wikipedia.org/wiki/Barnes_Wallis#Bomb_design

Mr. Oragahn wrote: No no, earthquakes have several ripples as far as I know, while the explosion you think of has one main shockwave and anything behind is quite residual.
Let's compare seismic activity resulting from a nuclear detonation and from earthquakes perhaps?

You are describing how Tallboy and Grand Small worked, and they are earthquake bombs. The energy travels through the ground rather then air.
http://en.wikipedia.org/wiki/Barnes_Wallis#Bomb_design

Take a look at a 5000 pound ANFO bomb
http://www.youtube.com/watch?v=vYKbBavXriY

You are confusing aftershocks with earthquakes.
http://en.wikipedia.org/wiki/Aftershock

Something you will want to watch some time.
http://www.youtube.com/watch?v=OFH2qZpLPKk
http://www.youtube.com/watch?v=7_PEG7S5_bo
http://www.youtube.com/watch?v=1Zyt5NNmMdU
http://www.youtube.com/watch?v=9c1oiyhL7Dc

The relevant part is at 5:28 to about 14:36. It is the part about earthquake bombs.
http://www.youtube.com/watch?v=09Yn1_Wnq_M

http://www.youtube.com/watch?v=C5yAZpzFeWw

OK I'll check the videos later. You seem right about the aftershocks. I wouldn't say to take wikipedia at face value, but for the moment here's what is said;

http://en.wikipedia.org/wiki/Earthquake ... arthquakes

Earthquakes can be recorded by seismometers up to great distances, because seismic waves travel through the whole Earth's interior. The absolute magnitude of a quake is conventionally reported by numbers on the Moment magnitude scale (formerly Richter scale, magnitude 7 causing serious damage over large areas), whereas the felt magnitude is reported using the modified Mercalli intensity scale (intensity II–XII).

+
http://en.wikipedia.org/wiki/Moment_mag ... arthquakes

As far as we can tell, the value obtained from the logarithmic scale is the one used to obtain the energetic value.
Anyway, I complicated matters because the relevant wave is the greatest one. Anything else, being weaker, won't make a difference if the most powerful one didn't threaten the target.

Since the focus = epicenter, it's most logical to look for very shallow focus earthquakes as a reference, or better, anything related to nukes, as you know.

http://en.wikipedia.org/wiki/Seismic_sc ... _intensity
http://en.wikipedia.org/wiki/Depth_of_f ... ctonics%29

http://en.wikipedia.org/wiki/Moment_mag ... explosions :

Such comparison figures are not very meaningful. As with earthquakes, during an underground explosion of a nuclear weapon, only a small fraction of the total amount of energy transformed ends up being radiated as seismic waves. Therefore, a seismic efficiency has to be chosen for a bomb that is quoted as a comparison. Using the conventional specific energy of TNT (4.184 MJ/kg), the above formula implies the assumption that about 0.5% of the bomb's energy is converted into radiated seismic energy Es. For real underground nuclear tests, the actual seismic efficiency achieved varies significantly and depends on the site and design parameters of the test.

0.5% means that you'd have to multiply the energy value by 200 to know what a nukes does.

There are two caveats with that though.

Firstly, depending on your conception of a TL bolt, either you believe it's a beam, thus more or less entirely directed into the ground with (although the blast crater it's still exposed to the sky) or it's more like some kind of bottled particle system, either where it's already some kind of superheated plasma that is self-contained and just needs to hit something, basically, to have its membrane pop, or it's more like a simile bomb which will react on impact.
The latest model potentially leading to the most explosive reaction, and thus the more blast and shockwave.
To me, from visual evidence and else, turbolaser bolts would not have anywhere the power of a nuke, especially according to the first model. From movies to shows, explosions induced by TL bolts don't look particularly violent.
The delivery of energy into the ground is solely based on the timeframe the bolt requires to deposit its energy. In the particle beam model, it is precisely the speed of the beam and its length which define how many particles get dumped into a given spot over a given time.

Secondly, this directly impacts on the efficiency of the weapon as the explosion will not happen underground, contrary to what is quoted above.
This is where it gets tricky because although a more violently explosive reaction would, in my opinion, produce more blast, there's the problem that unless it was focused by magitech, the explosion would largely be omnidirectional.
I don't remember the factor between an enclosed bomb and one exposed to air, but I think I read it was about four or something. What I mean is that once you'd have the value for your "underground" nuke, in order to get an adequate yield for your "surface" nuke, you may need to multiply the "underground" result by four.