A Rowboat In A Dark Ocean
Imagine you are rowing a boat on a dark, smooth sea at night, far from shore. You come across a tiny, floating sphere only a quarter of an inch across, the size of a pea. It is glowing very brightly in a searing whitish yellow, almost too bright to look at. You can see it from many miles away.
In fact, in the distance, you can make out other bright points of light. You decide to take your boat over to see the nearest one. But it turns out that the nearest one is 200 miles away! They all seem spaced out like this. Once in a while you find glowing orbs of bigger size. One of them is 30,000 miles from where you started by the pea-sized one. This big one is a deep orange and the size of a big beach ball, more than 2 feet across.
As you travel around, you realize that once every so often, you are also passing tiny dull red orbs, the size of a grain of sand. You can't see them until you are almost right on top of them, even though it is very, very dark. These dull ones are everywhere. There are 10 times as many of these dim red grains of sand, and you run across them every 50 or 75 miles.
You decide to map this strange, empty group of glowing peas, sand, and bigger orbs. You travel in a straight line for 4 million miles, and then you realize you are seeing almost no more shining pinpricks of light in that direction. You map this soft boundary between orbs and no orbs. You discover it is a huge circle, 16 million miles around. Outside that circle, nothing shines in the darkness.
Except in one direction. You see one faint smear, very far off. In your telescope, you can see that it is another giant disc of peas, three times bigger than the one you are floating in. But it is 100 million miles, or 20 Trillion pea diameters, away.
Glowing peas, each hundreds of miles apart, but so many of them that they make a disc 4 million miles across, floating in a dark sea.
This is our stars and galaxy, to scale.
If our sun were the size of a pea, the closest other star would be hundreds of miles away.
And our sun is almost a million miles across. The furthest humans have ever traveled is one quarter that far, from the earth and out around the moon, a quarter of a million miles.
People wonder if we are alone in the universe. Once you understand the scale of just how incredibly vast space is, how remotely cast even the “closest” stars are, you see that perhaps it doesn’t matter much. We are alone. We would probably be alone even if most stars have life.
The fastest rocket we have every built would take 50,000 years to get to the closest star.
This is about 5 times longer than human civilization as a whole has existed. Could we really expect to build a society that would survive that trip? No single human society has lasted even 5,000 years, and Earth-based societies have vast riches of resources, like air and water.
There is no reasonable expectation that we will soon be able to make rockets 1,000 times faster than this, to make the trip in “only” 50 years. Fusion rockets still need propellant, and bringing that much along, even accelerating it to near the speed of light with particle accelerators would still only move a ship 1/10th the size of its propellant to close to 1 million miles per hour in time for it to flip and start slowing down at the halfway point (really 68% point, because you can decelerate more efficiently with less fuel on board). That trip would still take 6,000 years.
Breakthrough Starshot moves the fuel off-board and propels 100 gram satellites with Earth-based lasers. But you still need hundreds of billions of watts of laser light applied for hours to accelerate to any significant fraction of the speed of light. And the satellite moves out of laser pushing range after that. Which means it needs to accelerate at nearly 100g, which would pulverize humans into mush. And there would be no way to slow down. At that speed, orbital capture and slingshot effects simply don’t work.
Is there hope for travelling faster than light? No. Physics simply will never allow matter to move faster than the speed of light in our Universe. If it could, there would be time travel, and we see no tourists. Further, it would violate causality and break physics in deep and serious ways. Even the claims of warp bubbles in recent news are completely fallacious, in that no warp bubble was actually created, and no reasonable engineering mechanism was even postulated. The most mathematically robust Alcubierre drive concepts still require the existence and capture of huge amounts of negative matter, which no one really thinks exists at all.
In our universe, human bodies and all other forms of matter will never travel faster than light.
I fear that the reason we don’t see evidence of galactic civilizations is simply that the journeys from star to star are too immense. Any group making such a trip would change societally and mentally so much, that by the time they arrived they would practically be a different species, not to mention a distinct culture from their planet of origin.
These colony ship explorers would not coordinate with their home world. They would become aliens. And this would continue even if they succeeded in making a stable world of their own that sent out its colony ships. Thousands of years for each voyage creates social divisions almost as vast as the distance between stars1.
Why coordinate? Why struggle to make an empire? You won’t be paying taxes or selling anything but designs and art and other things that can be sent digitally at the speed of light.
But the number one societal development in each colonizing group would likely be extreme self-sufficiency. They would learn to need nothing, and likely to even look down upon those that needed things from the home world, since external dependencies in a society living in an isolated, tiny environment would likely mean death. If you cannot make it or grow it or print it yourself, you pretty much can’t have it. You better not need it.
No, whether aliens exist or not, I think we are alone, specks around a pea in a vast ocean.
God only knows why the Universe is so vast. If stars were 10 or 100 times closer, then galaxies and stars would all be black holes, having gravitational fallen into each other long ago. So perhaps this is the only way stars with planets and life can exist in a Universe like ours…star-sized clumps of matter have to be far from each other, or it all falls in on itself.
So don’t believe the UFO stories. We almost definitely aren’t being visited. The novel preponderance of cell phones and cameras without vast increases in UFO sightings basically proves most UFOs are illusions, whether optical2 or psychological.
Your mental model of the world should not include potential alien visitors.
Your mental model of the world should not include humans visiting other stars in the next thousand years.
The Solar System is ours, even Europa; but it might be all we have for a very, very long time. And the humans that do colonize the other stars probably won’t even be people we consider part of “we” by the time they get there. The stars won’t belong to our grandchildren. AT most, they may belong to our grandchildren’s laser-driven fly-by probes.
But perhaps, once humans step out of their cradle and into the wider Solar System, there will one day be enough quadrillions of people in existence3 at Sol to create something inconceivable…a rowboat for the vast ocean.
The possible solution to this is if people didn’t experience time when transiting between stars, either by some type of suspended animation or an AI that didn’t run when in transit. But then, the home planet culture would progress vastly while they are asleep, and huge differences would still exist.
Mick West does an amazing job debunking the optical illusions that can even fool trained pilots.
Disassembling just one decent-sized moon and reassembling it as O’Neil cylinders would provide the firm ground and rotational gravity needed to support quadrillions of humans.
