Science indicates that the planet Earth has been orbiting the Sun for approximately 4.55 billion years.(1)Dalrymple, G.B. (1991) The Age of the Earth During that time the Sun has been orbiting the center of the galaxy, and in the process moving closer to and further from other stars. Currently the closest stars to the Sun are the Proxima and Alpha Centauri stars (A & B) which are currently estimated to be 4.37 light years away.(2)Söderhjelm, Staffan (1999) Visual binary orbits and masses post Hipparcos The Sun and Alpha Centauri are currently moving closer and are expected to reach a minimum distance of around 3.26 light years in approximately 25,900 years.(3)R. A. J. Matthews (1994) “The Close Approach of Stars in the Solar Neighbourhood” Quarterly Journal of the Royal Astronomical Society, Volume 35, Pages 1–8 After that the Solar system and Alpha Centauri system will be moving further apart, and 100,000 years from now Alpha Centauri will be too far from Earth to be seen with the naked eye. 100,000 years may seem like forever to humans, however it is only 0.002% of the age of the Earth.
If humanity were to plant a successful colony in the Alpha Centauri system in the next few thousand years, how long would it be until we had to abandon it? Would humans choose to remain in Alpha Centauri knowing that they would forever be cut-off from Earth and other humans? How many millions of years of wandering about the galaxy would it take for the Solar System and Alpha Centauri to get close enough for the two civilizations to come back into contact? The current estimate of the time it takes for the Sun to orbit the Galactic Core is 225 to 250 million years, however there is no reason to believe the Sun and Alpha Centauri would pass close to each other next time they pass. How much would the two human species have evolved during that time? Would they still be genetically compatible?
These questions are central considerations to any inter-stellar civilization. The Sun appears to be moving alone through the galaxy, whereas many other stars seem to be moving in groups. The Alpha Centauri stars are moving in the same group as Proxima Centauri, Luhman 16(4)Henri M. J. Boffin et al. (2013-12-04) “Possible astrometric discovery of a substellar companion to the closest binary brown dwarf system WISE J104915.57–531906.1” Astronomy and Astrophysics and Altair, in what is known as the G-Cloud,(5)Paulet Liewer (2000) Our Local Galactic Neighborhood NASA-JPL which the Sun is currently moving towards. A Centaurian or Altairian civilization could theoretically colonize within the G-Cloud with the knowledge that the stars are likely to remain in close proximity for a very long time. Terrans on the other hand do not have that luxury; we of Earth can only visit other systems, or choose to abandon Earth or unity forever.
References [ + ]
|1.||⇑||Dalrymple, G.B. (1991) The Age of the Earth|
|2.||⇑||Söderhjelm, Staffan (1999) Visual binary orbits and masses post Hipparcos|
|3.||⇑||R. A. J. Matthews (1994) “The Close Approach of Stars in the Solar Neighbourhood” Quarterly Journal of the Royal Astronomical Society, Volume 35, Pages 1–8|
|4.||⇑||Henri M. J. Boffin et al. (2013-12-04) “Possible astrometric discovery of a substellar companion to the closest binary brown dwarf system WISE J104915.57–531906.1” Astronomy and Astrophysics|
|5.||⇑||Paulet Liewer (2000) Our Local Galactic Neighborhood NASA-JPL|