Originally posted by GrandAdmiralAbaht
Taken from cannon sources in ESB it has been deduced that turbolasers have powers in the gigaton range. I can link you to stardestroyer.net or the technical commentairies by Dr. Saxton.
If you bother TO READ THE DAMNED WEBSITES you will see the obvious evidence to what I previously stated.
And if you're a cannon purist then you can continue to live in your litte world. The EU is official and is part of Star Wars. BTW, Dr. Saxton made extensive calculations in the Technical Commentaries and then applied them in the EPII ICS, which he wrote. So its not "pulled out of his ass" as you might say. Its fact.
Wow, you must be reading something other than me. Apparently the ESB reference you're refering to is the "asteroid vaporization" example right? Well, Dr. Saxton puts down calculations which seem seem to be within the kiloton range unless my arithmetic is wrong.
The section that refers to the "gigaton" range apparently is under the section labeled "Novel Evidence" and refers to novels who put down stuff like "turning a planet to molten slag" which I seem not to recall from the movies. Somehow I doubt that the novelists did extensive calculations to come up with that.
So, let's see, the famous "durasteel" that seems to protect Star Destroyers so easily against hundred-gigaton blasts against it. Yet Qui-gon seems to be able to stick his lightsaber in it and melt through durasteel blast doors in an instant. So I assume that means he's injecting hundreds of teratons worth of energy per second right? He must be using the patented
Exponentially Greater Than 100% Mass to Energy Efficiency Reactor(tm) in his lightsaber, which, must I remind you from your precious EU, is made up of parts you can by out of a local hardware shack and a crystal made in an Easy-Bake-Oven.
Oh and the famous all-powerful lasers when used against Yuuzhan Vong ships (also from EU) seem to only make little molten pecks in the flying turds. And the big hunks of plasma rock that the Vong chuck back (which can only possibly contain a few hundred terajoules, some hundred kilotons worth of thermal energy) seem to eat through shields (which are supposed to absorb hundreds of teratons) and the vaunted armor plating with ease.
And since when has EU been canon? I seem to remember about a dozen or so novels' stories being shot down at the slightest whim of George Lucas when the last two movies came out.
And finally let me show you some things:


See those? Now, the top picture is Baker, a puny and primative 20 kiloton nuke, but was enough to raise a column of water 2000ft in diameter and 6000ft (1.13 miles) high containing over 250 million gallons of water.
The Cannikin test (5MT), which I can't get a decent image of, was detonated a mile underground and caused a shockwave that registered 6.8 on the Richter Scale.
Now the second image, that's slightly more than 10 megatons, which was more than enough to vaporize the entire island, leaving a hole 1.2 miles in diameter as well as deep fry all marine life within dozens of miles, and create a core temperature that can reach well over 100 million C, 6-7 times hotter than the CORE of the Sun, which will turn any material in the universe into disociated atoms, no matter what kind of BS "durasteel" you can make up.
A 20MT nuke can release so much energy that mere exposure to the LIGHT (which is a by-product of the fireball heating air molecules hundreds of millions of degrees and releasing some of the subsequent energy of it as visible light) for a fraction of a second will cause a 3rd degree burn 40km from the fireball itself.
Now, 200 gigatons is 10,000 times more than that... No wait, you said that turbolasers are far more powerful than 200 gigatons, so lets say 800 gigatons. 40,000 of those.
In other words...
New Republic battling the Empire for control of Coruscant: "Oops, we shot off ONE stray turbolaser. We just utterly annihilated an area the size of Alaska (yes, I know they wouldn't know what Alaska is), and caused a very severe nuclear winter scenario that will render the planet uninhabitable for thousands of years. Sorry!"