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Cake day: October 6th, 2023

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  • We don’t know what the Great Filter is, but it must be pretty destructive for a civ. I just want to point out the fact that the Great Filter is probably still ahead of us and that we shouldn’t take our existence for granted.

    If there is a great filter…

    I mean, as you said, we’re pretty early to the scene. Why can’t we be the first in this galaxy? Perhaps planets like earth aren’t rare over the lifetime of a galaxy, but they are rare in these early years of a galaxy. In other words, earth just developed quickly, so now we’re here before any other earth-like planets have had a chance to develop intelligent life.



  • It’s simple. We’re the first intelligent life in the galaxy. There is nobody else yet in our galaxy.

    Also, probably nobody capable of traveling the stars wants to settle a planet. Once you figure out how to make huge spaceships (which you’ll need to travel interstellar space) you’ve essentially learned how to make cities in space. Our solar system would support a lot of people if we just used the resources available for space habitats, and by “lot” I mean in the quadrillions. And it turns out that all you need to support that population is a star to provide energy, and some planets to source materials from.

    So with that in mind, why bother finding another habitable planet?













  • That’s true, it does assume interstellar travel is physically possible, but at this point there are forms of interstellar travel that we know are possible.

    Solar sails for instance, we know those work, we’ve tried it. Now if you wanted to travel to another star system with a solar sail, it’s just a matter of scaling that proven technology way up. We’re not ready to do that today, and we won’t be ready in the next 20 years, but to think that we wouldn’t be ready in 500 years, I find that idea far fetched.

    But a much better technology would be fusion propulsion. With fusion drives you could get your cruising speed up to a meaningful fraction of the speed of light (perhaps 5-10%). At that rate you can make it to the closest stars in less than 100 years. And that technology is not at all far fetched. We truly are approaching working fusion power plants, it’s extremely likely that we can eventually develop fusion propulsion, or at the very least, fusion powered electrical propulsion (ion drive).

    As for if it will ever be economically possible, I’m not at all worried about that. The fact is, there are a lot of resources and opportunities right here in our solar system, just waiting for people to utilize them. So people definitely will start mining and manufacturing in space eventually. And as we start to operate more in space, we will naturally continue to iterate and improve our methods of getting around. In short, over time it’s going to get cheaper and cheaper to make space ships and we’re going to get better and better at doing it. The economic factors are likely to fall into place eventually.

    And finally, will interstellar travel ever be possible socially? Hey, your guess is as good as mine. I don’t think we have any way to answer that…


  • That’s definitely the right question! And honestly we don’t know, but it’s evident that we are first.

    Given the age of the universe, statistically it should have already happened by now.

    I’m not sure that’s true… I’m pretty sure that our sun is old for a main sequence yellow star in our galaxy. When you compare how long it takes for a star to get to the point ours is now, compared to the age of our galaxy, I believe it suggests that sol is part of a first wave of stars of its type. So if life really requires a star like this one to start up, then intelligent life starting just now could be right on time.

    Now why is our start perfect for life? Again, we don’t know, but evidently it is. Sadly we only have this one data point, this is the only star where we know there’s life. So assuming that something about our type of star is perfect is about as sensible as assuming that life could start around any star. Is it that other kinds of stars produce too much radiation in the Goldilocks zone? Or is it that other kinds of stars are too variable in the amount of heat they produce? Or that other kinds of stars don’t tend to have rocky planets? We don’t know, but something about main sequence yellow stars could be special, and we have one of the first of those stars in this galaxy.

    So declaring “we’re the first” requires some assumptions, but they aren’t crazy assumptions, and a lack of evidence of other older civilizations makes those assumptions stronger.

    And to your point, the universe is much older than this our star, so I suspect intelligent life has developed many times before us, at least in older galaxies. But sadly I don’t expect us to ever meet life from another galaxy. While I think stars within a galaxy are close enough for travel between them, galaxies are very, very far apart. I don’t think life has much chance of traveling to other galaxies, at least not without some method of ftl travel (which I am also not optimistic about).


  • The whole ship either has to have enough energy to last potentially 100000 years.

    Well, that depends on how far you’re going. If you pick a nice close target, let’s say 3 light years away, you can potentially get there pretty quickly. With fusion propulsion systems you could make the trip is something like 70 years, coasting most of the way. I’d need to check the math to get exact numbers, but I recall fusion allowing for pretty reasonable trip times.

    But if you can survive for hundreds or thousands of years, then solar sails become an option. Then it becomes a materials science problem of how thin can you make a sail that will still hold together. The greater the sail to payload ratio, the faster you go.