User:Gervankleef/sandbox

The Local Cosmic Habitat is defined as the cosmic volume centered on the Earth that can be traversed by space probes using current day technology, while maintaining communications with humans on Earth. Therefore the limits of this volume are set by the capabilities of current day space propulsion technologies and the life expectancy of humankind on Earth.

The main purpose of the Local Cosmic Habitat is to define the volume that has the potential to become the habitat of humankind. The Local Cosmic Habitat is a multi-disciplinary concept with applications in Science policy, space exploration, space situational awareness, astronomy, astrobiology, economy, philosophy and the study of the long term future of humankind.

The volume of the Local Cosmic Habitat volume can be approximated using the “Habitat Equation” $$R = V \cdot T$$, with $$R$$ the radius of a spherical volume, $V$ the velocity of a spaceship and $T$ the life expectancy of humankind on Earth.

A simplistic conservative estimate for the Local Cosmic Habitat assumes that current day propulsion technology can achieve velocities on the order of the escape velocity of the Solar System (~41 km/s). A simplistic estimate for the life expectancy of humankind applies the Copernican Principle to the total number of humans. The average estimate for the total number of humans that remain to be born then equals the number of people that have ever lived. The latter number is estimated to be about 100 billion. A rough estimate for the time it will take for the remaining 100 billion to be born is 725 years (assuming a constant birth rate equal to the 2016 value, 4.6 births /sec ). This sets R to 1e12 km. This is well inside the Solar System, and only ~15% of the total distance to the Inner Oort Cloud.

A more optimistic yet simplistic estimate applies the Copernican Principle to the lifetime of humankind as a species. The current age of the human species can be defined as the time since the Chimpanzee-human last common ancestor which is ~7 Myr ago. This sets R to about a 1000 light years. Such a volume includes about 15 million stars (see stellar density).