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Cake day: October 6th, 2023

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  • 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.




  • I don’t think there is a great filter. I think there’s an easy solution to the fermi paradox that doesn’t require great filters, we’re just the first intelligence in this galaxy.

    Here’s my reasoning: intelligent species that manage to develop space travel probably do tend to expand out into their galaxy. When they achieve this level of technology they can settle most of all of their galaxy in a matter of 10,000 years or so. That time period is very brief on an evolutionary scale. It’s estimated that life began on earth 3.7 billion years ago. That means it took about 3.7 billion years for earth to produce intelligent life, and then from that point it would take a mere 10,000 years to reach modern day, and 10,000 more years to settle the whole galaxy. That expansion happens so quickly compared to how long it took the planet to develop intelligent life, that the chance of two civilizations rising at the same time becomes very small.

    It all boils down to this: there are no intelligent aliens out there in our galaxy, because we are the first intelligent species in our galaxy. We know we’re the first because if we were second, then aliens would already have settled this star system.

    Probably there are lots of alien civilizations out there in the universe, but they’re in different galaxies.


  • Um, I think you’re mistaking species with kingdom.

    “Birds” are not a species, “mammals” are not a species. I don’t think viruses are even described in terms of species because they don’t reproduce sexually. I think you’ll find that when you actually consider species, most of my points hold.

    Various species have methods of communicating, from bees dancing to each other to whales having distinct regional dialects. Yes, humans have added some complexity to it by introducing technology, but that’s realy what it comes down to. Technology.

    Yes, many species have some rudimentary way of communicating some kinds of information. But obviously bee dances don’t compare to any human language, of which there are literally hundreds. A bee for instance has no way to express appreciation or derision for the English language. My whole point here was that humans, on hundreds of distinct occasions, developed languages capable of conveying complex ideas. No other species has developed a language half as capable as any of ours.

    Rather than picking the rest of that post apart, I’m just going to stop here. It’s pretty self evident that humans are impressive as hell. Denying that is… pretty dumb, and purely rhetorical.

    As a side note, don’t get too excited about fusion, it’s largely a dead end. I expect it will only be really useful in niche applications (like spacecraft). It will be far more expensive than nuclear fision and not really offer any benefits besides abundance of fuel. There’s still a huge radioactive waste problem. On the other hand, the sun provides all the energy we’ll ever need, and we’re getting better at collecting it. I’m really not concerned about increasing energy demands.




  • I totally agree. I know a teacher who who likes to say:

    “I believe there really is no such thing as a dumb question. As long as it’s an honest question (not rhetorical or sarcastic), then it’s a genuine request for more information. So even if it’s coming from a place of extreme ignorance, asking a question is an attempt to learn something, and the effort should be applauded.”






  • We aren’t even capable of caring for one another, let alone the EASIEST to maintain, most naturally human friendly habitat we would ever encounter in the cosmos as we evolved to fit it.

    I would argue that having 8 billion people in the same place makes earth the hardest place to live in some ways.

    One of the options that space habitats would allow for is smaller communities. What if you lived in a space station with roughly the population of a city? Your community wouldn’t necessarily need to be affiliated with other communities to make up a “country”, but it could be. Your community would have that option. And if the community is not geographically connected to the other members of its nation, there’s no reason they couldn’t change their mind, join a different country if you’re views seem better aligned. For the first time humans would have opt-in governance.

    Would opt-in governance lead to a more stable society? Would not being stuck geographically near communities with opposing views lead to less violent aggression? I don’t know, but I hope so.



  • Yeah, I think that really it wouldn’t be the “global community” that ends up saving the world in an asteroid impact scenario.

    It would likely be an organization that could operate on its own without endless committees. Say, the Chinese space agency, or SpaceX, or the Indian space agency. Someone would decide to just do it, without getting the whole world’s approval for the mission. Then the whole world would complain that the effort was made without any international cooperation or oversight. And the organization that literally saved the world would get chewed out by everyone because inevitably the plan will not have worked perfectly.

    But I’m not worried, because even billionaires don’t want to die. Someone would do something.


  • I don’t think we ruin everything… We’re also the best around at improving things, certainly improving our environments.

    I know it’s easy to be pessimistic about these things, but humans are evolutionary badasses. We’re capable of amazing things. I wouldn’t count us out just yet.

    Besides we haven’t really ruined anything. We haven’t done any damage to the earth that won’t heal eventually. The earth has seen many heating and cooling cycles and plenty of mass extinctions before and it will again (with or without humans).


  • As a species, we aren’t going to spread out there.

    Well not with that attitude!

    Yeah, space is hard and yeah mistakes have been made along the way. But things are definitely changing. Reusable rockets are nearly here… Between spaceX, rocket lab and stoke aerospace, there is real potential for these rockets to work. Hell, SpaceX has already conducted a successful orbital test flight.

    With reusable rockets we’ll start to see a drastic reduction in the cost to get to orbit, probably by two orders of magnitude, but possibly even more. With the cost down people will reassess the value of space and the resources available there. In other words, people will start doing more in space, and getting more from space. Resource collection, refining and specialized manufacturing are three most likely industries to start expanding into space. Once there is work to be done there it will begin to make sense for people to live there.

    As a species, we aren’t going to spread out there.

    Not today, no. But within my lifetime, I expect we will. Remember, change is usually slow and this would constitute the most profound change in human history.