The current population on Earth right now is estimated to 7 billion people. Ratio of civilian to military in (us) for example is about 5 military per 1000 civilians. If the Fallen, Hive, Vex, and Canbal all have a Earth size population, share a similar warrior to civilian ratio as the US. Then that would mean each enemy race would have 7million fighters for a total combined force of 28 million. Let's say they deployed 70% of their total force to destroy humanity in a surprise attack and left 30% to defend their home base the total attacking enemy force would be around 19.6million. There were a total of 4.6 million guardians in the BETA (not counting 6.5mil guardians because one player cannot control multiple guardians at one time) All guardians won't be present to defend the tower/last safe city. If the guardians were divided equally among 24 time zones and we take into account 8hr sleep and 8hr other activities for a total of 16hr time zones worth of guardians out of pocket. That would mean only 1.5 million guardians can possibly be present to defend this surprise attack. Each guardians quota will be 13 enemy combatants. Easy but there are spider tanks and bosses as well. On a rough estimate let's say for every 300 enemy troops we have 1boss and 1 tank type that would mean we have to deal with 130,666 combined force of tanks and bosses. Your chances of encountering a boss 8%. This is a cake walk but numbers lie.....Now if they have no such thing as a civilian population and decided to use their entire population to attack all 28 billion of them. We still only have the 1.5 million guardians...that would mean each guardians would have to deal with 18,666 enemy warriors divided into waves within enemy ranks would include 124 bosses and tanks that EACH individual guardians have to fight off to protect humanity...in the course of maybe around 3 hours....then we are screwed. Edit:1) number of guardians have been adjusted for accuracy Edit:2) there are some very good responses to this forum that encourages critical thinking in many aspects of Destiny. If you have created a new forum discussing these types of topics please let me know. Edit:3)To clarify this is waves after waves pounding the tower that EACH guardian (1) has to handle in one session: probably some where around 2 hours or 3