Yes, it comes down to range and speed which Covi plasma torpedos have both of. There is one weakness they could use, but they would have to be close enough to fire and they will have a short firing window. The Covenant have to drop a small section of their shields around the weapon so it can fire, but they would only have a few seconds. 

Also, the Covenant frigate from The Fall of Reach took two MAC rounds before the nuke was fired and knocked it's shields out and may have damaged the FTL drive.

This has been a UNSC transmission.

Just want to clear something up, a isoton is actually closer to Gigatons, not Megatons.

P.S. I don't consider the Nova to be a feasible technology. Come on, 9 8 Megaton bombs (tops) creating a explosion with the same density as a neutron star. Total bull.

and phasers are total bull.  as is moving faster than light without relatavistic effects.  and the structure of the engines on the various NC-1171s.  the in-line engine and hull structure is much stronger and more feasible, as it relies less on tensile strength.  Under heavy damage, the UNSC and Covenant ships will function much better, due to back-ups and structural support.

this debate is not cenetered on the feasibility of the technology, but instead on which side is more powerful.

forgive me, but I'm working off of memory, so you're just going to have to settle for me doing what the Star Trek side does: giving little to no reference data, and few measurements that are known.  I do note that Josef did provide a good amount of references, tho

1) The Covenant Plasma Torpedoes can easily turn around on their earlier course, retaining their previous speed.  This is due to the fact that they are not fire and forget weapons, like phasers, and are guided by magnetic field manipulation.  this is the source of their speed.  This was demonstrated by Captain Jacob Keyes, who first performed the Keyes Loop (I believe this was mentioned in First Strike, but can't be sure) in the Battle of Sigma Octanus IV (http://halo.wikia.com/wiki/Keyes_Loop).

2) to be able to completely crystallize a planet's surface in a matter of hours is no mean thing.  planets are big.  they have huge amounts of surface area.  and even a fleet of two-three hundred ships (standard combat fleet size for the Covenant) of five to nineteen kilometer long ships will not cover very much space.  Earth, a relatively small planet, has approximately (If I did my math right) 6966331437.57, 7000000000, or 7x10^9 square miles

3) there have been thirteen fleets mentioned in the Halo series, all of which involved in the war on the UNSC, most of which have two to three hundred ships each.  The Second Fleet of Homogeneous Clarity consists of at a bare minimum 2.5 thousand capitol ships, with uncountable strikecraft.  there must be many more fleets behind Covenant lines, maintaining order and garrisoning their worlds, should a rebellion or invasion arise.

4) The standard MAC gun, equipped on nearly all UNSC frigates, cruisers, and capitol ships, delivers a 600-ton projectile at a muzzle velocity of 600,000 mph.  this results in 360,000,000,000 joules.  that's 360 gigajoules of force

The "Super-MAC", mounted on orbital MAC defense stations, and theorized to be mounted on the UNSC Supercarrier delivers 21.6 zettajoules of force, or 5867.5 Gigatons of TNT.  This is from a 3,000 ton ferric-tungsten round with a muzzle velocity of approzimately 40% the speed of light. (http://halo.wikia.com/wiki/Magnetic_Accelerator_Cannon)

5) Covenant ships are also armed with two other main weapon types: the Energy Projector, and the Pulse Laser Turret.  The Pulse Laser Turret (PLT), seen in Halo: Combat Evolved in use against the Pillar of Autumn, is a commonly mounted weapon on Covenant ships, ranging in size from the handheld Beam Rifle, much like the human SRS 99D AM Sniper Rifle, to large scale anti-capitol ship weapons capable of melting through at least 45 centimeters of Titanium-A armor plating in a single shot.  being a laser, this would pass through any Star Trek shield, as they are transparent. (http://halo.wikia.com/wiki/Pulse_Laser)

The Energy Projector is a weapon mounted only on Covenant capitol ships, due to power constraints, and is the weapon used to "glass" planets.  it is both an antiplanetary weapon, and is an anti-ship weapon.  It has a range of at least 50,000 kilometers, exceeding even that of an orbital MAC gun, making it a long range sniping weapon that is absolutely devastating.
when used in ship-to-ship combat, a single shot can remove a ship from combat by destroying its weaponry, disable a ship, or completely destroy a ship, with a single shot.  They have been observed to "gut a ship from stem to stern in a single shot", such as the frigate Gettysburg in the Battle of Reach.  Its size is variable, thus its power is also variable.  it can be focused into a pinpoint, giving it insane amounts of power, and the ability to carve a ship apart, or can be expanded to cover square miles of land

6) The Nova bomb, which is nine fusion warheads encased in lithium triteride (from here on reffered to as LT shell), has huge destructive potential.  So much, that is literally a planet-killer, and is nicknamed as such.  loosely calculated, it has a 27 gigaton yield.
this is because of a) nine fusion warheads, assumed at 30 megatons each; and b ) the LT shell reflects the blast in upon itself, thus increasing the strength a hundredfold and compressing the core to neutron star density
(http://halo.wikia.com/wiki/NOVA_Bomb)

and 7) Inertial dampers are used by both sides of the Human-Covenant war, most extensively by the Covenant.  The Covenant use them both for utility and for show, as evidenced by views of water flowing up, down, and sideways.  this is reffered to as gravity manipulation, as well as inertial damping.

-Orodum

beware the ninja cylons!

This is the sort of thing I hate with a passion. You say its closer to gigatons, but give no source beyond what you put up. Give a source to back you up, ok?

And so what the NOVA is not feasible technology? This is about who kicks who's ass. Not who ever has the more feasbile tech. And you have to remeber that the universe is a big place, anything could be possible. For all we know a Halo ring could appear out of Slipstream space and enter orbit around Jupiter of Saturn tomorrow.

And off of memory here is the size of the Covenant's ships. Frigate=1000 meters. Destroyer=1455 meters. Carrier=1455 meters. Cruiser, I can't remeber if it's larger then the others. CCS-class Battle Cruiser(CCS stands for Covenant Capital Ship)= 1782 meters. Battleship=2000 meters. Reverence-class Cruiser=3000 meters. Supercruiser=3566 meters. Assault Carrier=5346 meters. Supercarrier=it is unknown, but it would most likly range from 7 kilometers to 12 kilometers max.

This has been a UNSC transmission.  

ST plasma weapons are weak. Covenant tech is based off of what the Forerunner used, and I don't think guys that can move a star and the orbiting Dyson Sphere into a Slipspace rift a few meters across would have a weak weapon.

And you said "mostly energy" which means there is a soild casing for the explosives that can be hit. But even if that is not possible they can just run the plasma torpedos into them like the Spartans do in The Ghosts of Onyx.

And what were the yields of these nukes? 10 megatons? 20? 50? 100? Using "primitive nuclear weapons" that are very powerful the UNSC built the NOVA bomb which is more likly far more powerful the 27 gigatons that Halopedia gave it I think. UNSC Shiva warheads most likly became far more powerful during the war with the Covenant from 2525 to 2553. And thanks for the sources, I'll watch Enterprise next time its on.

First off it is the CCS-class Battle Cruiser that is 1.7 kilometers long. The Assault Carrier is the 5.3 kilometer ship. And I should have said small SSD since the Super Carrier could be 7 to 12 kilometers long. If the ship list you look at said frigates were 150 meters long go up and you will find a list of all Covenant ships, with Supercarrier at the end after the AC. And as already said, even with dozens of ships or hundreds of ships a planet is a big place. Can the Federation purify the surface of the planet, boil away the oceans and lakes and atmosphere with only 36 ships in one hour? And also the Covenant don't have to engage at such long ranges, they can jump in to say 300,000 kilometers then turn you into an expanding cloud of super heat gas and dust.

And I would say anything of the CCS-class and above would take out the Enterprise. You have to remeber that Covenant fleets come with dozens or hundreds of ships.

Good, will my PC is working again without freezing or lag.

This has been a UNSC transmission.

Wrong! To many Trek fanboys who will not give me the data I need to compare with the Covenant. If the "primitive" UNSC can build a bomb powerful enough to " shatter a planet in two" then they are more advance then you think.

If you want a "serious debate" then start arguing about what ST has in this time line that would help it. If any one has an idea for a better ST time line bring it up. But if you want to debate start debating don't just attack fans or people who may just agree with Halo, do you see me really doing that? I known I got anger and lost my temper, but you should start debating before High Charity gets to ST Earth and sends down a re-armed Forerunner Dreadnought to destroy the surface.

This has been a United Front Against People Who Expect Every one Else to Agree with them and not fighting the enemy the right way transmission. Hm? That my be a bit to long, but you get the idea.

Did a little math because I had nothing better to do(and wanted to know the answer myself)

 Mass of Earth's oceans: 1.4E21Kg
1.4E21 x 1000 = 1.4E24 grams
Assume 17 degress Celsius for oceans

Raise temperature to 100C
1.4E24 * (100C-17C) * 4.186J/g C = 1.4E24 *(83)*4.186 = 1.4E24 * 347.438 = 4.864132E26 J
4.864132E26 J to raise the temperature from 17C to 100C
Now add the energy required for vaporization:
1.4E24 g * 2261 J/g = 3.1654E27 J
Add: 4.864132E26 J + 3.1654E27 J = 3.6518132E27 J
1 kiloton  = 4.184E12 J
3.6518132E27 J / 4.184E12 J/kt = 8.728E14 kt
1 pt = 1E3 tt = 1E6 gt = 1E9 mt = 1E12 kt
1 et = 1E3 pt = 1E6 tt = 1E9 gt = 1E12 mt = 1E15 kt
8.728E14  / 1E12 = 872.8 peta-tons total to vaporize all of Earth's oceans

On page 8 of The Fall of Reach it says that 3 dozen Covenant ships(destroyers and cruisers) managed to vaporize the oceans and glass all land on a planet during the hour the Master Chief watched.

The Covenant are throwing around very heavy firepower.

Also, super MACs are NOT mounted in any ship produced by the UNSC.  The entire super MAC station IS the MAC, in fact the power requirements are so massive that Reach needed massive planet based power generators to power its super MACs.  Since there is no physical connection between the super MACs and Reach, the UNSC must be sending power wirelessly in some form.

If anyone sees a mistake in my calculations or formulas used please point it out.
Vaporizing water formula from here, joules in a kitoton here

Scientific prefixes here

Its late and I'm tired, but if I'm right then the NOVA bomb is using somthing besides Shivas.

6000 Megatons x 9 x 100=540 Teratons. Yikes! Just one of the warheads without the rest could destroy any Covenant or ST ship besides the big mobile stations like High Charity.

And as I said its late and I'm really tired so if I got this wrong tell me. Good night.

This has been a UNSC transmission.

I totally disagree, I really dont' think it really could compare, trek ships are much more faster in movement, even weapons are more powerful, along with that, photon torpedos gives a yield of 25 isotons, and then quantum torpedos gives a maximum yield of 50 isotones, according Memory Alpha, the best trek wiki out on the web, one photon torpedo of 25 isoton could level a city, and then if you just double that to around 54 isotons with a gravametric charge can blow up a small planet, now I would like see halo weapons do that

Beside, trek have the possiblity of using the omega molecule which the Halo people can't even begin to harvest.

Considering that 'isotons' are a fictional unit of measurement, until someone provides calculations on what one isoton is equivelent to they are totaly useless in this debate.

Is it really hard for people on the Star Trek side to properly cite their claims?

I have provided weapon range and weapon speed for the Covenant that is beyond anything the Star Trek side has proved.

I am honestly starting to get annoyed at the claims made about Star Trek without evidence.

Next time someone makes a claim about Star Trek, I want the episode/movie that backs it up.  Even better, provide a video link of it happening.

Failure to provide evidence to back up a claim will result in it being dismissed until evidence is provided.

One photon torpedo with a yield of 25 isotons destroys a small city, and a yield of 54 isotons destroys a small planet, suggesting that mass measurements in Star Trek are mysteriously exponential. If by "small planet", they mean something like the moon, the lower limit of the energy required to destroy the moon is 1.234 * 10^29 J, or about 30 trillion megatons of explosive force. So a single photon torpedo in Star Trek carries 30 trillion megatons of explosive force--and that's not even the largest torpedo, as higher-class torpedoes have yields of up to 200 isotons, and a range of 8 million KM. The torpedoes would not even have to come close hitting any vessel in Halo, even considering that explosions in space dissipate rather rapidly, they could miss by miles and destroy fleets.

((VOY: "Dreadnought", "Scorpion, Part II", "Living Witness", "Human Error", "The Voyager Conspiracy")

The Nova bomb, by comparison, carries about 5.4 million megatons as you mentioned, and was a prototype bomb that cost an awfully large amount, and was very heavy and apparently difficult to launch. Whereas a photon torpedo is easy to launch. If the ship is stationary, the torpedo can be launched at warp 9 ((TNG: "Pen Pals", "The Emissary"), or 1516c (http://www.trekmania.net/science/warp_scale.htm). At this speed, the photon torpedo would traverse its 8 million km range in about .01774 seconds. 

So to sum: a photon torpedo has a yield of 30 trillion megatons, can be fired from 8 million kilometers, and can reach its target faster than the blink of an eye.