There is also an interesting discussion with His Holiness here that indicates the Buddhist texts describe Mt. Meru differently, which is interesting. If it is a definitive thing, why the different explanations?
That being so, then Mount Meru and so on explained in Kalachakra, in reality, have a deeper meaning. They are mainly referring to the abiding situation of the body of a human being of the Southern Continent (Jambudvipa). The presentation of an external Jambudvipa is there in Kalachakra because of the necessity for explaining the relation between the external and internal worlds - each of them symbolize and are parallel to the other. In that sense, it is not necessary that Mount Meru exist as a giant mountain standing somewhere in reality in some separate location.
His Holiness on how to balance approaches between science and Buddhism
Berzin: Serkong Rinpoche said that Mount Meru in Kalachakra looks as though it is over your head and about to fall on you. What is that referring to?
His Holiness: In the Abhidharmakosha, Mount Meru is square and here, in Kalachakra, it is round and gets larger on top. Jambudvipa is around the bottom of it so that when you look up the wider top portion of Mount Meru, it appears hanging over your head. Thus, it looks as if it is about to fall. http://www.sangye.it/wordpress2/?p=3566
Berzin: So it would be best not to say that what science says is just like Buddhism?
His Holiness: Science has the same approach as Buddhism does. I think that from this point of view, they come to the same thing. That is one of the basic Buddhist attitudes. For instance, there are two types of distorted antagonistic attitudes (log-lta): those that are interpolations (sgro-’dogs) and those that are totally imaginary (kun-brtags-kyi log-lta) [equivalent to repudiations (skur-'debs)]. What do these categories refer to? An antagonistic attitude believing that something that exists does not exist is a distorted attitude that repudiates. One that believes that something that does not exist does exist is a distorted attitude of interpolation.
For instance, if Mount Meru exists and we say it doesn’t, that is a distorted attitude. If it doesn’t exist and we say it does, that also is a distorted attitude. That means that whatever is the fact, that is what we accept. For instance, if on the ground, there is an elephant and it is visible, we should see it because it is visible. Using this line of reasoning, if something exists (and is visible), we should see it. And, if it should be visible and we don’t see it, then it doesn’t exist.
So like that, concerning whether or not Mount Meru exists, when you explore in spacecrafts and if definitely it should be visible - because it is described as an object of the eye sensors - and if we don’t see it - of course, if it is something that exists but it can’t be seen, that is something completely different - but if it is the case that if it exists it has to be visible, then if it can’t be seen, we can decide that it doesn’t exist. Since the texts say that Mount Meru does exist, then except for them being of interpretable meaning, [there is no other possibility].
If we research scientifically, then if something exists we should be able to confirm it decisively - for instance, the diameters of the sun and the moon. I don’t remember the exact figures, but the diameter of the sun is much greater than that of the moon. We can see this with valid visual perception; it’s been seen. However, Abhidharmakosha says that the diameter of the moon is fifty yojanas and that of the sun is fifty-one - only one yojana difference.
Now, let’s leave aside the possibility that Mount Meru exists but just can’t be seen (because it’s invisible); we can directly see the size of the sun and the moon. We can see the sun and the moon and, if the sun and moon are visible, it can’t be that we cannot see their sizes. We can see their orbs. We can feel their heat; we can see their orbits; and we can see their sizes. Since we can see them, then when we look at them, we can see there is a big difference.
So, when Abhidharmakosha says their diameters are fifty and fifty-one yojanas respectively, this has to be refuted as an interpretable level of meaning. To say that what we see in terms of mathematical calculations is not the case - that it’s a deceptive appearance - and what Vasubhandu said in the Kosha about their being fifty and fifty-one yojanas is true, we couldn’t possibly say that. That is the basic Buddhist attitude: when there is a scientific finding that has been proven, we must accept it.
When science doesn’t find something, there are two possibilities: the not finding of something that doesn’t exist and the case of even though something exists, it can’t be found. They are different. For instance, about past and future lives and not being able to prove them scientifically, it is just that scientists cannot find them, but that doesn’t prove that they don’t exist.