Often in discussions involving Tengen Toppa Gurren Lagann (abreviated to), people state that it isn't galaxy sized but planet sized; going on about the comparison sizes; not just here but in many places. Needless to say, I find this annoying and infuriating. The reasons they state this so are:
1. Super Galaxy Gurren Lagann (a mecha the size of the Moon) jumped out of TTGL's mouth, showing a clear comparison in size.
2. The Grandzambomia's (the Anti-Spirals mecha) hand was about to grab the Earth.
3. The Anti-Spirals homeworld is seen on top of the Grandzabomias head.
4. They were in the Anti-Spiral universe, where size is distorted.
Firstly, I must point out that the first two points contradict each other. One states that TTGL is the size of the Earth, the other the Earth is the size of its hand. Despite this, these two arguements are used together to state that TTGL is Earth-sized. Infact, they would often state that TTGL is both Earth sized and bigger than the Earth in the same thread. On a closer inspection of the scene in which Super Galaxy Gurren Lagann is compared to Tengen Toppa Gurren Lagann, green spiral energy comes from TTGL's mouth as it opens its mouth wider before Super Galaxy Gurren Lagann emerges from the green light. It is not, as the doubters would put it, a clear conparison of Super Galaxy Gurren Lagann coming straight out of its mouth. Infact, when Super Galaxy Gurren Lagann emerges from the spiral energy, TTGL can't even be seen. Such can be seen here (skip to about 4 min 40 seconds in to see this).
Next, the Grandzabomias hand in comparison to Earth. To reply to this, I'm not going to go on about science or physics, but story telling.
The reason that the Grandzabomia's hand was shown next to the Earth was to show that it was going to grab the Earth, not because it's hand is the same size of the Earth. The Grandzabomias hand would have blocked out the entire screen in comparison to the Earth. The Earth was just made bigger so that the viewer could see it, rather than it being an invisible speck which had to be view by zooming aaaaall the way in and the Grandzabomia's hand blocking out the entire screen. As for the Anti-Spiral homeworld, if not it's size for the reasons mentioned earlier in the parragraph is another simple reason; because it looks cool. The Anti-Spiral homeworld, the planet which they had been looking half the series is a part of the design of the Anti-Spirals final and ultimate form to prove their determination to subdue any Spiral Level life form that poses a threat to the Universe. One arguement stated that it is impossible for a rock based planet to be millions of light years across. Maybe this is so; all of the rock based planets we know are smaller than the smallest gas planet. But does this apply to Gurren Lagann? Let me repeat to you one of the key themes in Gurren Lagann:
Kick logic out and do the Impossible.
Yet whenever this is mentioned, the response is that it is still impossible and that these physics still apply to the world of Gurren Lagann (despite the fact that they said many times in the show that physics meant nothing, before proceeding to break it). From the earliest stages of the show, before any aspects of space are involved (aside from the mysterious prolouge), the impossible is kicked to the curb. But as said before, physics always applies to the world of Gurren Lagann. In the first episode, Kamina and Simon ride a vortex of pigs several hundred meters into the air, then somehow survive when they are knocked off by the village chieftan. When the Spiral King is defeated, Spiral King Lord Genome is able to talk with both his lungs gone. During the battle with the Anti-Spiral warships, pace, which consists of absolutely nothing, is condensed into liquid form like that in a deep sea trench, and proceeds to crush Super Galaxy Dai-Gurren. Not to mention many instances of ridiculous falls being survived scrachless, Lagann being able to regenerate Gurren's broken parts from absolutely nothing, colossal metal robots getting thrown about like ragdolls, sometimes by mechas no bigger than themselves. There are so many other moments in this show these left unmentioned. However, when it comes to the final episode, all this changes and the laws of physics suddenly apply. Then again, perhaps Lord Genome had invisible lungs just after he was defeated by Simon. No offence to hardcore anime fans, but animes are a form of cartoon, and in cartoons, the laws of physics mean nothing. Here is a classic example of some cartoon physics...
See how Bugs Bunny and Marvin the Marsian are able to survive in exposed space with no space gear? Notice there is gravity? See how Marvin plans to destroy the Earth with a firework, and later on survives a direct point-blank explosion from a planet destroying firework? Actually your wrong. The whole thing takes place on Earth with no venturing into outer space because cartoon physics don't apply to cartoons. The laws of physics have been shown to apply in other animes, such as Gundam, but not in Gurren Lagann (or almost anything by Gainax for that matter).
Speaking of the comparison of Super Galaxy Gurren Lagann to Tengen Toppa Gurren Lagann, I do remember there was a size comparison of the two. In the second last episode when they escape the Multiversal Labyrinth, it shows Gurren Lagann going into Arc Gurren Lagann, which goes into Super Galaxy Gurren Lagaan before zooming out to show the Anti-Spiral prison world (which is at least bigger than the Moon). From there it zooms out to show the star system, then nearby star systems untill it finally shows the galaxy, from which Tengen Toppa Gurren Lagann emerges. Curiously, those who seem to have something against galaxy sized robots seem to forget all about this part. There's no green Spiral energy blocking your vision either.
It's also of importance to note the backgrounds. It's a common argument to hear that the galaxies grabbed and thrown in the final aren't real galaxies as they are created by the Anti-Spirals in the Anti-Spiral dimension, and are therefore not much bigger than planets themselves. Yet before the final showdown, Super Galaxy Gurren Lagann is seen battling the Anti-Spiral warships, and in the background are stars. The battle against the Anti-Spiral warships and the amarda of giant stone hands & feet, it is important to say, is all within the Anti-Spiral dimension. Shortly after TTGL emerges, the Anti-Spiral create the Granzeboma, stating that no-one had ever come this far and that they would defeat them in the same form that brought them so much comfort. As shown in the previous three episodes, the Anti-Spiral had encountered Spiral Races with planet-sized warships and gunmen trying to fight back, only to be crushed by the Anti-Spiral. Which means at least one other Spiral race escaped liquid space and defeated the Anti-Spiral warships only to be locked into the Multiversal Labyrinth. The size that the doubters usually have for TTGL is 5 X 10 (probably means five times across by ten up, incase you are wondering) the size of Super Galaxy Gurren Lagann, and thus the Moon. However, the Anti-Spiral Warships are clearly a lot, LOT bigger than 5 X 10 that of Super Galaxy Gurren Lagann. If TTGL really is 5 X 10 that of Super Galaxy Gurren Lagann, than it would still be smaller than the Anti-Spiral Warships. Yet according to the Anti-Spiral, no one had made it as far as Tengen Toppa Gurren Lagann...The size of Gurren Lagann compared with the Anti-Spiral warships can clearly be seen here, particually at the end (notice also the stars and planets in the background).
On top of all of that, there is one simple fact; Gainax themselves have confirmed that it is galaxy sized. Firstly, they released the Gurren LAgann official handbook, which states that the official height of Tengen Toppa Gurren Lagann is 10 million light years tall. As a guess, I would say that this is it:
I'm not entirely sure what it says or if it's even the right thing, so if anyone can read Japanese that would probably help a lot. Next comes an answer from an interview with Gainax about Gurren Lagannfrom a fan.
Could TTGL exist in normal space?
TTGL could exist in normal space as it creates the Super Spiral Space within itself.
Planet sized gunmen, such as Cathedral Terra Drednaught Lazengunn (later renamed Super Galaxy Gurren Lagann), are able to maintain their forms in ordinary space. If TTGL was really planet sized, would it need Super Spiral Space to exist in normal space, as other planet-sized warships and gunmen exist in normal space without the aid of Super Spiral Power? The Anti-Spiral also managed to defeat not only Lord Genome and Cathedral Lazengunn, but countless other Spiral Races from across the Universe at the same time. Now, just sit and imagine yourself as an anime creator. What would you do for a final battle?
A) Have galaxy-sized robots fight each other.
B) Make it look like they are galaxy-sized but are really just slightly bigger than planet-sized robots fighting in a smaller-than-it-looks-universe for no apparent reason.
Note also that many fans were hugely disapointed with Gainax for the ending of Neon Genesis Evangelion, recieving lots of hatemail and even recieving death threats. Would this same company choose to trick their loyal fans again, on purpose, for no good reason? Let me finish off by saying this; who is it that states that Tengen Toppa Gurren Lagann isn't actually galaxy-sized? Is it the creators? The reviewers? The fans? Or even Wikipedia? It's actually none of the previously mentioned, but from people who are not fans of the show, and go on forums and websites to have arguments about who can beat who (I doubt they've even watched the show, just gone on Youtube to see if they can make things up about it being smaller than it looks for some petty reason). Well, this concludes my rant; next time something makes me angry I might just rant again. Or I can say something positive. Like "Believe in the me that believes in you!"