Physics behind the Greek phalanx formation?

[Fanghur]

This is probably a question better suited to a history forum, but since it does largely involve basic physics, I thought I might as well just post it here. I recently watched a documentary on the famous Battle of Thermopylae, and I find myself at a loss to explain how the Spartans managed to hold their ground against a charge of thousands of Persians. In the pass there were 300 Spartans forming the phalanx blocking the Persian army from accessing the pass, and they were up against literally thousands of Persian soldiers. What I don't understand is this; as strong and well trained as the Spartans were, the fact remains that they were still only 300, backed by about 8000 other Greeks, who are somehow able to maintain their phalanx even though much larger number of Persians are smashing right into their front.

 

Now, to me the physics here seems pretty straight forward: tens of thousands of Persian infantry crashing head on to a phalanx of 300 Spartans. To me it should seem as if the Persians should have been able to smash right through the Greek lines like a battering ram through a curtain, since I don't care how strong the Spartans were, the mass and by extension the momentum of 10 000+ Persians would have dwarfed that of 300 Spartans. Yet despite this, when the 10 000 Persians first smashed into the phalanx, not only did it not move at all, but the Spartans were actually able to push them back and go on the offensive. The numbers just don't seem to add up here; 300 men withstanding the combined momentum of thousands? It doesn't seem possible.

 

Can someone tell me what I'm missing here? Because clearly something else must have been at work here, otherwise what I said would absolutely be correct.

[Phi for All]

Actually, the phalanx might be better discussed in the Psychology section. Much of it's success was in showing, to the attackers who mostly thought of themselves as individuals, a united front against opposition. It's a bit daunting to think of attacking such an organized enemy who isn't charging or fleeing, but rather staying calmly in one place, ready to meet your single attack with locked shields and determination.

 

I guess physically the phalanx was most effective at the Battle of Thermopylae because it didn't allow the pressure of the attacking Persians to seep in from the sides (flanks), providing a tight seal for the pass. I've also imagine that the Persians numbers worked against them at a certain point, making it difficult (and scary) to keep up the pressure as you walk over the heaps of your own dead to get at the wall of shields and spears presented by the Greeks.

[MattyG]

Also, keep in mind that the Greeks were defending a narrow pass. The Persians may have had superior numbers, but it was never all the Persians attacking all the Greeks at once. Lets say that the pass is only wide enough for 20 Greeks to stand shoulder to shoulder. Well, that means that at any given time there can only be around 20 Persians attacking at a time, possibly less if they're not attacking in formation. And as long as the Greeks keep their shields up, it's going to be difficult to break the line. I hope that helps.

[Fanghur]

Yes, but while only 20 Persians can actually engage the phalanx at a time, the reality is while that might be true, it's still the column of Persians would still be thousands of men deep. 20 Persians at the front, pushing against the phalanx, with thousands of Persians behind them who are pushing against these twenty. That being me back to my original question; how could the Greeks possibly have held their ground against such a massive amount of weight and momentum slamming into them like a battering ram? Again, the numbers just don't add up.

 

Another example, if the pass was only wide enough for one person to pass at a time, it's true that one person could conceivably hold back a much larger force in an actual sword fight, since only one enemy at a time could engage him. However, if 20 enemies did a hands-on-shoulders charge at him, each one right behind the one in front, then the single defender would not be able to offset that momentum and would fall beneath them.

 

So why didn't this happen in Thermopylae?

Edited October 7, 2012 by Fanghur

[mathematic]

Yes, but while only 20 Persians can actually engage the phalanx at a time, the reality is while that might be true, it's still the column of Persians would still be thousands of men deep. 20 Persians at the front, pushing against the phalanx, with thousands of Persians behind them who are pushing against these twenty. That being me back to my original question; how could the Greeks possibly have held their ground against such a massive amount of weight and momentum slamming into them like a battering ram? Again, the numbers just don't add up.

 

Another example, if the pass was only wide enough for one person to pass at a time, it's true that one person could conceivably hold back a much larger force in an actual sword fight, since only one enemy at a time could engage him. However, if 20 enemies did a hands-on-shoulders charge at him, each one right behind the one in front, then the single defender would not be able to offset that momentum and would fall beneath them.

 

So why didn't this happen in Thermopylae?

I presume the Greeks were killing the Persians who came at them, so the mass meant that Persians would have to step over the dead bodies of those who had been ahead.