# How Would An Advanced Alien Civilization Expand the Lifespans of Giant Stars (Nearly) Exponentially? [closed]

Long ago, in some distant galaxy, an advanced civilization had turned a small, young elliptical galaxy into their own astronomical playground. They seemed to have come up with a way to prolong stellar lifespans. For further clarification, they could theoretically prolong the lifespan of a blue supergiant (20 times wider than our sun, 20-1,000 times as massive and 1,000-one million times as bright) from ten million years to ten billion, a yellow hypergiant (1300 times wider than our sun and 500k-750k times as bright) from a few million years to a few billion, and a red hypergiant, which has a natural lifespan of 100,000 years, can live as long as a red dwarf.

Through artificial, technological means, how would this advanced alien race prolong these giants, supergiants and hypergiants far beyond their natural limits?

• The civilization is undefined. The future is undefined. The technology is undefined. How can this question possibly be answered? Since the technobabble tag was completely shot down, I had to VTC:OB. Even if we open this up to wild flights of fancy, how will you judge a best answer (which is how to avoid closure as opinion-based)? – JBH Apr 17 at 21:48
• You could always just handwave it by stating that the star now achieved a higher proportion of mass-energy conversion than the 1%. It doesn't actually break the laws of physics and is suitably vague enough to be considered plausible. – Madman Apr 17 at 22:22
• Quick comment on mass - a supergiant won't reach $\sim1000M_{\odot}$; the cutoff for stars is roughly an order of magnitude below that. By the way, related questions, albeit targeted at less massive stars: worldbuilding.stackexchange.com/q/134250/627, worldbuilding.stackexchange.com/q/192618/627 – HDE 226868 Apr 17 at 23:11
• I want to leave it open on the basis of science-fiction as a tag, which is what it is, but the lack of constraints for a best answer rears it's ugly head as JBH sais. If you can give us more to narrow it down, then you should be ok. – A Rogue Ant. Apr 17 at 23:52
• @ARogueAnt. Narrow it how? – JohnWDailey Apr 18 at 0:19

Technobabale mass energy conversion

Stars usually use fusion, which has a mass-energy conversion ratio of about 1%. If you want to have your stars live longer you could always just wave your hands and say that they achieved 10% or 100% mass-energy conversion, which would extend their life spans to a degree, maybe not by a factor of 100 but they would exist for a longer time period, eg 100 million years blue giant to 1 billion years, or yada yada.

Potential handwaves are

• Antimatter produced in nuclear reaction to achieve a higher mas energy conversion rate
• Blackhole stars- eg hawkings knots
• More efficient fusion
• Cutting out some "waste" product of the stars that's not necessary
• Exotic particle physics
• High-density particle physics
• Violation of symmetries which result in conservation of energy
• Magic
• Etc
• You have a good list, but one that also raises some new questions. 1) How do Hawking's knots really work? Google doesn't have much info on such. 2) What do you mean by "exotic" or "high-density particle physics"? 3) Similarly, what does "violation of symmetries" mean? – JohnWDailey Apr 18 at 0:05
• @JohnWDailey 1) Hawking's knots, in most forms work by, to simplify dramatically harvest the Hawking radiation of black holes(Hawking radiation its self being a bit more complicated than portrayed to the public), while feeding them mass, allowing for potentially near 100% mass-energy conversion, creating "stars" which if used properly could use anything as fuel, including a star providing the mass flow inwards and the energy radiated outwards are at a stable ratio so the amount of Hawking radiation radiation and the mass of the black hole is constant. – Madman Apr 18 at 1:23

Some stars fade out because they run out of fuel; not much that can be done about that.

However, other stars explode because of core collapse before burning all of their fuel: supernovas. The elements at the core of the star have fused to iron which cannot be further fused to release energy to sustain core's pressure against the weight of the outer layers of the star, causing it to implode and then supernova. The solution is "obvious"; a gargantuan tubular force field created through (technobabble goes here) is driven into the heart of the star to vent out the useless iron, extending the life of the star until all fuel is burned. The vented iron (quintillions of tons of it) is either allowed to escape the star's gravity into interstellar space or collected using (technobabble goes here) for some purpose (Dyson sphere or somesuch).

This works for other star types as well; e.g. a red giant forms because it isn't massive enough to trigger fusion of the carbon / oxygen at its core. This "dead" core material can be extracted and vented or even launched using (technobabble goes here) to a larger star that is massive enough to burn it.

• "The elements at the core of the star have fused to iron which cannot be further fused" Within the almost nil constraints of the question, this could be hadwaved away through technobabble to allow iron to fuse further, thus allowing the star to 'burn put' rather than im/explode. – Justin Thyme the Second Apr 18 at 16:24