7 Civilizations, Past: 110 Billion
If the assumptions are modified by raising the civilization lifetime to 500,000 years, the cumulative number of civilizations emerging into the Galaxy rises to 110 billion (Table 4).
Table 5: Cumulative Civilizations, Assumptions 3
| Civilization Time Available, years | 5,500,000,000 |
| Planet Civilizations Emerging, per year | 0.02 |
| Total Number of Civilizations | 110,000,000 |
| Available Sequential Time-slots | 5000 |
| Assumed Civilization Lifetime, years | 500,000 |
| Concurrent Civilizations |
10,000 |