"Promising hints of life on distant planet"

[Rabulias]

For example, given the serious nature of our impending environmental collapse, I wouldn't just order contact, I would start sending as much of our history and literature and art to them as possible (let's assume we could figure out how, including some sort of mathematical Rosetta stone) just to ensure that something of our civilization might survive us.

If we established contact with an alien race, it would be quite sad if they sent us the same stuff for the same reason...

 

[Reynard]

If we established contact with an alien race, it would be quite sad if they sent us the same stuff for the same reason...

That, my friend, is a GREAT Twilight Zone episode idea.

 

[Stalker0]

Why do you need to know whether it's a zero or one? So long as you're getting some signal through, and can tell "right now there's a signal coming through, and now the line is dead", you can just revert to Morse code - brief or long bursts of signal are dots and dashes. Or zeros and ones if that's your preferred flavour.

So a deeper (but still simplistic) answer is this:

If you have Alice and Bob who are light years apart, and then both share an entangled particle. If Alice just does a measurement on the particle and its in state "1", she knows that Bob's particle is also right now in state 1. Neat....but not useful.

To actually communicate, Alice has to be able to direct the particle to be in State 1 or State 2 as a simple binary example. And unfortunately, the forcing of that state breaks the entanglement (called decoherence).

 

[Jfdlsjfd]

If we established contact with an alien race, it would be quite sad if they sent us the same stuff for the same reason...

Now imagine if they were 1,432 light-years away, and by the time we get to listen to their signal, there is a chance they might have disappeared. Hearing their death throes for a millenium, THAT would be depressing.

 

[Ryujin]

So a deeper (but still simplistic) answer is this:

If you have Alice and Bob who are light years apart, and then both share an entangled particle. If Alice just does a measurement on the particle and its in state "1", she knows that Bob's particle is also right now in state 1. Neat....but not useful.

To actually communicate, Alice has to be able to direct the particle to be in State 1 or State 2 as a simple binary example. And unfortunately, the forcing of that state breaks the entanglement (called decoherence).

Thanks. That's the explanation that I needed.

 

[MarkB]

No it isn't. Mass is mass.

Yeah, but size isn't mass, especially when it's a big hollow object. A deliberately designed metal ship would use significantly less mass than a hollowed-out asteroid of equivalent internal volume.

 

[Morrus]

Why do you need to know whether it's a zero or one? So long as you're getting some signal through, and can tell "right now there's a signal coming through, and now the line is dead", you can just revert to Morse code - brief or long bursts of signal are dots and dashes. Or zeros and ones if that's your preferred flavour.

A signal doesn’t ’come through’ though. The particle is just spinning one way or the other based on what the other is doing, and you can’t know which until you look at it. And you don’t know what the one at the other end is doing (until you look at yours). There’s no ‘message’ or ‘signal’ to actually detect--it's not like it suddenly starts spinning and you can have a little alarm tell you that's happened. It always was spinning (well, it's more complicated than that as it's a quantum state so it was all Schrodinger's Cat until you looked at it, but for practical purposes it may as well always have been).

This confuses the hell out of me, too. My grasp on it is incredible weak!

 

[Ryujin]

Yeah, but size isn't mass, especially when it's a big hollow object. A deliberately designed metal ship would use significantly less mass than a hollowed-out asteroid of equivalent internal volume.

But an asteroid has the advantage of carrying much of its own manufacturing materials, for future use.

 

[Mustrum_Ridcully]

From an engineering perspective AI might have a lot easier time of it than us squishy humans

AI needs hardware resources that needs electricity and produces a lot of heat (and cooling is a concern in vacuum), and the components also degrade from radiation. And innately, computers have absolutely no self-repair capabilities. To some extent, you can turn off defective processors or memory, but repairing is its own infrastructure that currently includes humans. If you switch to robots (AI powered or really simple algorithms, it's still computers at the end), you of course also have to think about how to maintain those robots. You will need a lot of spare parts and/or a long chain of machinery that build all the parts you need, including the parts to repair that machinery. You really don't want your nuclear reactor or fusion reactor to break down.

It always boils down that you need some sort of self-sustaining eco-system. Not necessarily self-sustained forever, but for the duration of the travel. If you also want some form of colonization, you also need something to make the place you reach hospitable to whatever "colonizes" it (be it AI and robots, human colonists from a generation ship or whatever.). Even if we detect life on such a planet, there is still the question if we could eat anything we find there, and if the atmosphere has the right composition. (And for the AI and robots, the existence of life isn't a great help, unless it includes friendly aliens that would help repairing and maintaing them.)

The problem isn't getting enough space. Ceres has a volume of about 27% of that of the Moon. And, if that's not enough, if you can move an asteroid to another star, you can move them around here until you had a glob of them that was big enough.

The real problem is that if - how the heck do you move an asteroid to another star?

Which is part of the machinery that I figure you need to bring aboard - fuel and engines, maneuvering thrusters.

 

[Reynard]

Yeah, but size isn't mass, especially when it's a big hollow object. A deliberately designed metal ship would use significantly less mass than a hollowed-out asteroid of equivalent internal volume.

Maybe, but you still have to shield against radiation and impacts. By the time you armor it up, you may have lost any mass savings.