Do you believe we are alone in the universe?

The universe is far, far, far too big and ancient a place to reasonably rule out life elsewhere. Even if the galaxy is currently lacking intelligent life other than our own (and I'm not convinced it is - our expectations of what intelligent life should be doing with itself is, obviously, prejudiced toward our own ideals), I don't think it was nor will be. I'm also much more optimistic about FTL.

 

[Hussar]

To us. You have no idea whether it would or would not be compelling to an alien culture.

Math is still math, no matter what. In order to actually travel to another star, let alone multiple stars, requires a huge expenditure of resources. Even unmanned probes still require a massive undertaking. And for what? So you can plant a flag on some rock that is so unimaginably distant that communication is vitually impossible?

We don't understand a great deal about how the universe works. It's hubris to think we know for certain whether or not it's possible to have perfect replication.

Unless everything we do understand is 100% wrong, then we DO know that perfect replication is impossible. Perpetual motion machines are a physical impossibility. Third Law of Thermodynamics isn't a suggestion.

Science of the universe which changes annually as we discover new things and find out we were wrong about old things, oh and find out we were wrong about the new things we thought we were right about.

Not really. The basic underpinnings haven't changed in thousands of years. Pythagoras and Pi aren't really up for debate. Sure, we're finding new stuff. But, most of that is quantum level stuff that doesn't really apply on the macro level. We might as well wish for magic faeries. Granted, sure, we could be wrong. That's possible. Just really, really unlikely at this point. And more and more unlikely every year that goes by.

 

[Doctor Futurity]

You don't know that, though. You have no idea if a sentient dinosaur clan evolved and was destroyed by a volcano or meteor strike. Sentience may well have appeared and vanished dozens of times before it finally took off.

Of course not. I don't know such information any more than you could assert otherwise. We can safely say that we have yet to find any evidence of prior sentient beings on Earth....and yes, we are also aware that it is possible something sentient arose ten or a hundred million years ago and failed the Pass Go evolutionary test for any number of reasons. It does not disprove my point that the only certainty we have is that we're the ones who showed up and are asking this question right now, and we are self evidently real. We can't realistically hypothesize prior sentient beings with any accuracy on Earth any more than we could do so for life on other planets; the main difference is that Earth is finite in scope, we can study its geologic and biologic history, and we have two centuries of paleontology to help us out in this regard. Everything about everywhere else is conjecture.

Occam's Razor is a very simple deductive tool in scientific reasoning. I don't think you and I are disagreeing on anything, other than that I think it's prudent to assume there have been no true sentient species prior to modern upright-walking, tool using hominids without some evidence, and you seem to be taking the stance that absence of evidence is not evidence of absence. Which is fine, but not really a useful contribution to the conversation from a scientific perspective.

 

[Hussar]

Our resources are finite. Sooner or later we will have to start harvesting large meteors and other planets, regardless of the cost.

Sure. But, by the same token, if we're positing things like perfect replication, then we no longer need to start harvesting anything. We have the technology to make the planet a perfect paradise for everyone. So, again, why are we suddenly deciding, "Hey, yeah, we've got everything we could possibly need or want at our fingertips, let's dump all try to send probes to other solar systems for fun"?

And, again, if we have the technology to harvest meteors and whatnot, now we have the resources to keep the Earth going for the lifespan of the species.

 

[Umbran]

Newton still applies. That whole pesky third law where entropy increases over time. It's not a technological issue, it's an issue with the universe. Unless our basic underpinnings of understanding of the universe are wrong, you cannot ever have perfect replication.

Well, technically, you could have perfect a perfect replication. But, we aren't talking about replicating things once. We are talking about doing it millions of times. And having them progress across a million years, maintaining that perfection in systems? Then, entropy gets you, and those devices either die, or evolve....

Basically, it is a living species. Those don't stay the same over geological time periods.

 

[Shasarak]

That's not a "statisctic". It is an estimate. And it pretty much assumes no time is spent in the self-replicating. The Milky Way is about 105,000 light years across. So, it takes a million years to cross it at 0.1c, if traveling in a straight line, non-stop. If you have to zig and sage to reach stars with reasonable resources, and take time to build new probes, it would take longer.

I dont really mind if you want to disagree on the amount of time required. If you want we can increase the time needed by an order of magnitude, so 10 million years because we want to take our time to spread out properly, do some sight seeing and really check out all the planets we find for life. Compared to the amount of time to get to our present day, 10 million years is nothing compared to 13 billion years. Even 100 million years is nothing.

Note that this assumes the existence of a *self-replicating* machine, that can fly across interstellar distances. And, that machine self-replicates with no notable change, *for a million years*.

With respect, that's not a great assumption. Over those timescales, any self-replicating system will be subject to selective forces - leading to evolution or extinction.

That is a good point. Imagine if the machine was improving itself as it went. Probably you would not want it to because who knows what it would evolve into but it is possible. There is a lot of time to think between systems.

But in any case a quick google search showed the top ten Oldest Animal Species On Earth: the youngest is Martialis Huereka-120 million years old and the oldest is Cyanobacteria – 2.8 billion years old. So are Cyanobacteria breaking Newtons laws of Thermodynamics?

 

[Shasarak]

Over the course of human discovery, one common thread has been that Earth isn't particularly special. We aren't the center of the Universe, or the Solar System. Ours isn't a particularly uncommon type of star. The galaxy has a bazillion of them. And the Universe looks pretty much the same in every direction, with a bazillion more galaxies each with its bazillion stars. We are also not particularly separate from other animals - with other species on the planet sharing 90% and more of our DNA. We have a couple of small differences that lead to stunning differences in behaviors, is all. We used to think we were special, even anointed, but it turns out... not.

So, when we pose the question of whether we are special in the Universe, which way should we lean?

Except that it turns out that yes Earth is particularly special.

Earth is the right distance from the Sun (not too hot, not too cold)
Earth has a large neighbouring planet (Jupiter) that helps to shield it from asteroid strikes etc
Earth has a relatively large moon that helps to stabilise its rotation
Earth has plate tectonics which drives the carbon cycle helping to regulate the temperature.
As you say Earth is positioned out in the suburbs of the Milky Way which protects us from being sterilised by a nearby gamma burst.

I am sure there are others that I can not remember off the top of my head (like the magnetosphere protecting the earths atmosphere), but each of those factors is critical for maintaining a stable environment suitable for the development of life.

 

[Yaarel]

An important feature of planet Earth, is our unique Moon.

The Moon stabilizes the Earths tilted axis and makes day-and-night and seasons consistent and regular. It turns out the Moon is extraordinarily important for life.

Without the Moon, most of the lifeforms as we know them are impossible.

 

[Shasarak]

But the cost to get to the point where you can actually realistically send settlers is so high and takes so long that it likely is never going to happen. No government is ever going to start a program that is going to take a thousand years to complete. And that's what terraforming is. A thousand year or more project. There's simply no way that any group of people is going to invest in something that will only benefit their many times great grandchildren. Never minding keeping that investment going for that long.

Of course they wont start a project that will take a thousand years to complete. There is going to be a ten year plan, which will naturally lead to another ten year plan and so on and so on. The city of London has been around for two thousand years and do you think that the people who first lived there imagined what would happen over the next hundred, five hundred or two thousand years? Of course not.

Perfect replication is impossible. That's why we have evolution. Breed rabbits long enough and you don't have rabbits anymore. If that happens with your machines, then they don't explore anymore.

There are creatures who have existed for hundreds of millions of years. How is that even possible if what you say is correct?

Again, the sunk costs of something like that are so great that it's never going to happen. And, frankly, why? What's the goal here? To send physical probes? Terraforming? You can't send people, they'll never survive the trip.

What was the point of sending Voyager out into the void between solar systems? What was the point of spending 12 billion for a 3.5 mile railway track in New York? Did Khufu really need such a big Pyramid, I mean who is going to pay for that sucker?

I think Neil deGrasse Tyson said it best when he pointed out that all the money spent on space programs is spent on Earth, so it is not as if we are losing money to do it.

 

[Shasarak]

An important feature of planet Earth, is our unique Moon.

The Moon stabilizes the Earths tilted axis and makes day-and-night and seasons consistent and regular. It turns out the Moon is extraordinarily important for life.

Without the Moon, most of the lifeforms as we know them are impossible.

The other thing to note about the Moon is that the impact that caused the Moon also helped to spread metals close to the surface of the Earth where we could find and use them more easily.

Because pretty hard to have a Bronze age without Bronze.

 

[Maxperson]

Math is still math, no matter what. In order to actually travel to another star, let alone multiple stars, requires a huge expenditure of resources. Even unmanned probes still require a massive undertaking. And for what? So you can plant a flag on some rock that is so unimaginably distant that communication is vitually impossible?

Or maybe just to see if you can do it. Or maybe to see if it's really as cold as you thought it was. Or maybe... Who knows what would motivate an alien species? Not you. Not me.

Unless everything we do understand is 100% wrong, then we DO know that perfect replication is impossible. Perpetual motion machines are a physical impossibility. Third Law of Thermodynamics isn't a suggestion.

Not really. The basic underpinnings haven't changed in thousands of years. Pythagoras and Pi aren't really up for debate. Sure, we're finding new stuff. But, most of that is quantum level stuff that doesn't really apply on the macro level. We might as well wish for magic faeries. Granted, sure, we could be wrong. That's possible. Just really, really unlikely at this point. And more and more unlikely every year that goes by.

You're overlooking Mork's Law of Telelportinamics and Alf's Skizzblix. Those get around our issues.

Seriously man, there's a ton that we don't know and there could be work-arounds those issues that we haven't discovered yet.