What will happen when the Sun will become a red giant, after the hydrogen fuel will be exhausted in the nucleus? The sun will expand well beyond the internal planets, just engulfing Earth with its huge red envelope. Earth, together with Mercury, Venus, Mars and many asteroids will be burned out. Life will disappear all of a sudden.
Our theory of stellar evolution today is very sophisticated and computer simulations based on mathematical models fitting observations of star clusters is quite accurate. Unfortunately it is not yet able to predict with sufficient time resolution when our Sun will become a red giant: with the science of today the error would be probably plus/minus one million years. Therefore if this happened today – not so as we probably still have one billion years of safety – we would be all fucked up.
Let’s suppose that all this happens at some day in the long-term future and that our astrophysical science is at that time sophisticated enough – thanks mostly to the help of artificial intelligence – to allow us to predict the time of the onset of the red giant phase with an error of plus/minus 100 years. What could we do then in order to save our life and civilization? The only way would be to migrate to other stars where exoplanets have been previously discovered to orbit just in the habitability zone.
Clearly only a tiny piece of humanity would have the privilege to be saved. The best way would be to build huge space arks, whose pieces would be assembled in the circumterrestrial space during a time period of 50 years. Imagine a spherical or cylindirical thing having a diameter of 1 Km, hosting 10.000 passengers and one million human and animal frozen embryos. Projects of such space habitats – which are expected to be self-sufficient for hundreds years – have been already imagined many years ago by physicists Freeman Dyson and Gerard O’Neill. Such arks would work like artificial planetoids rotating around their axes, where artificial gravity would be created in the inner part of the external surface and where huge Earth-like habitats (with plants, rivers, hills, houses) would be reproduced. Such gigantic structures could permanently orbit around Earth or the Moon, or they could vectored to other stellar systems.
At some point some propulsion system – such as a huge sail driven by a powerful microwave generator or by a matter/antimatter device – would thrust a number of those arks out of Earth’s orbit towards the chosen targets, which could possibly be some solar-type and/or red dwarf stars in the range of 100 light years, where Earth-like planets with no sign of civilization have been previously discovered by astronomers.
After some years the space arks would accelerate up to a speed of 1/100 of the light speed, and finally after 1000-10000 years they would reach their destined stellar systems. At that point, while the arks will remain in orbit around the chosen planets, several exploring shuttles would land on the planet, after orbiting drones would have scanned all the planet in order to identify the most favorable zones where to land. In some planets the procedure might go well, in others it might not. After all the goal is to transfer mankind to another Earth.
The interstellar travel might be much faster if arks can enter inside the mouth of wormholes, assuming (hypothetically) that natural wormholes are quite commonly spread in the interstellar space (after all they could be an important component of dark matter in the universe), and then go out from the other side almost instantaneously. Alternatively, if no wormholes are available in the area and if the available technology will be able to suck enough negative energy from the quantum vacumm, the arks could warp spacetime around them in order to accelerate the travel. In such a way after a travel of 50-100 years using conventional propulsion up to the entrance points and then out of them, they could arrive to destination in maximum 150 years.
At that point, if luck assists, new humanities would grow and develop on some extrasolar planets, especially after all the embryos will be grown and then multiplied together over some generations. Exactly the same process might have happened to non-human civilizations who had to face the same problem million years before. Some of them might be still observing Earth, occasionally sending ranger-shuttles to explore and then decide what is the case to do. Finding a technological civilization like us in the Solar System – even if much less developed than theirs – might be a great disappointment to them. Some of them might decide to invade, some others might decide to change destination. Fighting for survival must be really a common denominator to all intelligent civilizations in the Universe, as well as to animals.
• My soundtrack of the story here:
https://totemtag.bandcamp.com/album/interstellar-exodus
• Something of my peer-reviewed science regarding all this here:
Teodorani M. (2006). An Alternative Method for the Scientific Search for Extraterrestrial Intelligent Life: “The Local SETI”. In: J. Seckbach (ed.) Life as We Know It, Springer, COLE Books, Vol. 10, pp. 487-503.
Teodorani M. (2014). A Strategic “Viewfinder” for SETI Research. Acta Astronautica 105 (2014) 512–516.
Teodorani M. (2014). Search for High-Proper Motion Objects with Infrared Excess. Acta Astronautica 105 (2014) 547–552.
Dr. Massimo Teodorani 