The largest known galaxy in the universe, IC 1101, might be one of the least likely places for complex life to exist. If this galaxy nevertheless hosts multicellular creatures on planetary surfaces, their conditions for survival are extraordinary. Microbial life could subsist in subsurface oceans or brine pockets, even in quite extreme places in the universe.
IC 1101, located a billion light-years from Earth, is in a league of its own. It contains a staggering 100 trillion stars. In comparison, our Milky Way hosts only 100 to 400 billion. However, it will not get any more of them, as it had already run out of gas for star formation 10 to 11 billion years ago, when the universe was 3 to 4 billion years old, or 5 to 6 billion years before our system formed. It forms zero stars a year on average.
This means that in IC1101, more stars are red dwarfs than in our galaxy. All huge, blue, and hot stars exploded as supernovae when the universe was already very young. Stars like the Sun already transformed into white dwarfs, and if any hosted technological civilizations like ours, they either went extinct or had to move to other systems to survive.
It’s an open question if red dwarf stars, which can exist up to 12 trillion years, can host complex life on the surface. Such stars flare and can damage the atmospheres and oceans of planets in their habitable zones, which are tight because these stars are not as hot as our Sun.
Furthermore, not all stars can host surface organisms and technological civilizations in IC1101. About half of the stars have a safe Rosetta orbit, which is centrophobic. The rest experience infall into the center of this vast galaxy on each revolution.
Not all is lost, though. This galaxy is so immense that one orbit can take 2 to 4 billion years in the galactic edge zone where tens of trillions of stars reside, so even stars on boxy orbits can develop their own technological civilizations on a revolution around their galaxy. Additionally, boxy orbits don’t always take stars to the center of the galaxy; they can also take them relatively far away.
However, over 11 billion years and among 100 trillion stars, there might have been dramatic extinctions of complex surface life and technological civilizations due to infall into the galactic center, and this journey was extraordinary.
Some doomed systems and their planets would reach speeds of 0.5% to 4% of the speed of light during this infall because the gravitational potential of IC1101 is so extreme. During the lifetimes of individuals living on these worlds, stars would visibly move, and making out constellations would not make sense.
The center of the galaxy is inhospitable. There is a lot of radiation from high-density stars and the supermassive black hole. Stars are positioned very close to one another, and there is a high chance of interference with infalling star systems with living planets. These worlds could be ejected and become ultracold rogue planets; planetary systems could be disrupted, and planets could collide with other planets or stars, resulting in destruction. Systems’ asteroid fields can be disturbed, causing intense bombardment of living planets. It could result in tragic extinction events.
For sentient species to be subject to such a sorry fate must have been immensely sad and dramatic. Hopefully some could have developed advanced enough technology to leave their system on time for a safe one with a Rosetta orbit.