Hello, SFIA audio listeners. In this month's Nebula exclusive, big alien theory,

we're asking the reason alien civilizations might be rare is because most aliens are huge.

To hear it and every episode early and ad-free, plus hours of bonus content,

check out go.nebola.tv slash Isaac Arthur and use my code, Isaac Arthur.

Throughout history, it has been common for distant colonies to break away from their homeland.

In a future where colonies are entitled planets and night years from home, shall history repeat itself?

The colony fleet, Aldous of Heaven, that arrived in Beta Pictoris in 2998, after 63 light years of travel, was very loyal to their ancestors on Earth, and Beta Pictoros was the third colony

they had founded

since leaving the Lagrange dockyards on a planned multi-millenia journey.

Their small fleet was a guardier fleet, as they were called, colonial missions who might

spend a century between each stop, where they would let out part of the crew to settle

a new world, stock to take on raw materials

and fuel, then move out to their next target, manufacturing new colonial equipment, and

having children to raise more colonists, expanding and upgrading their ships, and sometimes

even making new ships. At each stop, they do it again, letting off anyone who wants to settle and helping set

the basic colony up, while taking on materials and plotting their next leg.

In turn, those colonists would help send supplies and information to that fleet, and help

maintain the infrastructure of relays and stelazers that would permit future trade and immigration

to take place faster

and easier. The first two systems the fleet colonized, now known as Brush and Esol,

were doing their job admirably. Indeed, the first colonial reinforcement fleet from Earth

was already en route at nearly half of light speed along the huge laser relays now connecting

...