Adventuring around a Giant Star [Space]

AlexanderHowl · 02-16-2019, 08:33 AM

Certain star (G4 or larger) will become giant stars late in their life. A G2 star (similar to our own) will become a red giant (cooling by 2,500 K), but its L will increase by 40, pushing the habitable zone from 1.0 AU to 6.25 AU. A large ice world would transform into a standard ocean world and, with the 1 billion year lifespan of the red giant, could have enough time to become a standard garden world. The radius of the start would increase to 0.09 AU, well below the size portrayed by most science fiction authors, but nearly twenty times larger than during the main sequence.

The inner worlds would still exist, but they would have suffered massive devestation. An Earthlike world would have a temperature of 700 K, turning it into a Standard Cthonian or Greenhouse planet. In the former case, explorers can scavenge the ruins. In the latter case, the dangers involved would be too great.

So, let us assume that an interstellar civilization explores a red giant system halfway through its lifespan. Would it be worthwhile to terraform an ocean world or colonize a garden world? What other interesting elements would you expect to find if it had been the home of a TL12 interplanetary civilization (one that never discovered FTL) 2.5 billion years ago?

Rupert · 02-16-2019, 10:14 AM

After 2.5 billion years it's palaeontology on the oldest rock strata, looking for strange isotope ratios and deposition layers that might give clues as to whether or not there was a civilisation on the planet or not. Unless that TL12 culture set out to make monuments that would last 'forever' there's going to be nothing left on the worlds of the inner system.

You'd be much better off rummaging through any asteroid belts, gas giant trojans, and airless planets or moons in the outer system, in my opinion.

02-16-2019, 08:33 AM	#1
AlexanderHowl Join Date: Feb 2016	Adventuring around a Giant Star [Space] Certain star (G4 or larger) will become giant stars late in their life. A G2 star (similar to our own) will become a red giant (cooling by 2,500 K), but its L will increase by 40, pushing the habitable zone from 1.0 AU to 6.25 AU. A large ice world would transform into a standard ocean world and, with the 1 billion year lifespan of the red giant, could have enough time to become a standard garden world. The radius of the start would increase to 0.09 AU, well below the size portrayed by most science fiction authors, but nearly twenty times larger than during the main sequence. The inner worlds would still exist, but they would have suffered massive devestation. An Earthlike world would have a temperature of 700 K, turning it into a Standard Cthonian or Greenhouse planet. In the former case, explorers can scavenge the ruins. In the latter case, the dangers involved would be too great. So, let us assume that an interstellar civilization explores a red giant system halfway through its lifespan. Would it be worthwhile to terraform an ocean world or colonize a garden world? What other interesting elements would you expect to find if it had been the home of a TL12 interplanetary civilization (one that never discovered FTL) 2.5 billion years ago? Last edited by AlexanderHowl; 02-16-2019 at 02:20 PM. Reason: Corrected due to math error

02-16-2019, 10:14 AM	#2
Rupert Join Date: Aug 2004 Location: Wellington, NZ	Re: Adventuring around a Giant Star [Space] After 2.5 billion years it's palaeontology on the oldest rock strata, looking for strange isotope ratios and deposition layers that might give clues as to whether or not there was a civilisation on the planet or not. Unless that TL12 culture set out to make monuments that would last 'forever' there's going to be nothing left on the worlds of the inner system. You'd be much better off rummaging through any asteroid belts, gas giant trojans, and airless planets or moons in the outer system, in my opinion. __________________ Rupert Boleyn "A pessimist is an optimist with a sense of history."