Breaking free of our planet

[Gazabone]

There's some interesting discussions on SGL so I thought I'd court views on the following statement made at the end of a program on the moon landings a night or so ago (didn't see the whole program, just caught the last couple minutes, it was on just before "Man v Universe");

An interviewee said, "Humans, just happened to be Americans, actually broke free of their own planet. They travelled to another planet and eventually landed on it...."

Apart from the obvious bit about describing our moon as a planet, what about describing the moon landing as breaking free of our planet? What was going through my mind is, can it really be described as breaking free of our planet when you're still very much within its gravitational pull? I know I'm being rather pedantic and the moon landings were truly magnificent achievements, but I'm still curious what others think about the interviewee's description.

[Mr Spock]

Breaking free of our planet probably refers to escaping the gravitational pull. Don't forget they only slowed by orbiting The Moon.

Of course, The Moon is a moon and not a planet. I suppose you could describe the Earth/Moon as a closed system, so therefore they only went 'nextdoor' rather than leaving the system.

[ronin]

The whole area is a bit blurred.

Gravity is infinite, the sun acts on us, we act on the sun, we act on Jupiter, Jupiter acts on us.

It is the planets acting gravitationally on their suns that has enabled us to identify so many exo-planetary systems.

To an extent, a bit on the small side I will agree, we act on Andromeda and it acts on us.

I suppose the statement was (possibly) based on the idea that had they not used the moon to slow down and turn round then they would have kept going. In effect ceased orbiting the earth. Their outward velocity having at some time exceeded the escape velocity. In which case "free" is determined by velocity and distance and not specifically fixed.

There may be a value that is defined as "free", as in <1/1000g = free. g= 9.81ms^-2

[Calculon]

Eh, it's semantics really. Landing on the surface of a celestial body other than our own was pretty monumental of course!

[andrew s]

In the sense we went and stayed, albeit briefly, an order of magnitude further away than ever before I agree. In the sense we became independent of our planet permanently no. Even for a colony on Mars our gravity could still have a measurable but very small effect.

Regards Andrew

[ollypenrice]

Of course it was a great acheivement but they took their own atmosphere with them and lived inside earth-replicating suits which they couldn't take off. They never touched the lunar surface, only their suits did. Now you could say this is nit-picking and small minded but I mention it only in the context of stretching the moon landings to imply that we are outward bound from our home planet and have taken the first step.

I don't see us as likely to leave Earth prmanently. I don't subscribe to the argument which says, 'They said we'd never fly or do this or do that but we did,' because the endgame of that argument is to say that everything is possible and it just isn't. (In my view.) We humans are very drawn to the idea of eternal life (no religion, please) and for some the eternal life of our species means learning to colonize other planets when ours has had it. I simply don't think we will. We do not just live on this planet, we are of it.

Olly

[D4N]

I think the drive is enough for a permanent colony on Mars to happen in my lifetime, whether it survives or not is another thing as that place isn't exactly hospitable.

However once one starts it is likely that others will too as a lot of the unknowns will suddenly be known.

Advances in 3D printing will help a lot, to be able to take self replicating factories along will solve a lot of problems.

The moon would be easier to set up on but harder to stay, the long term effects of being in such a low gravity environment aren't fully understood let alone how things like foetal development will be effected.

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[Dave Lloyd]

Of course it was a great acheivement but they took their own atmosphere with them and lived inside earth-replicating suits which they couldn't take off. They never touched the lunar surface, only their suits did. Now you could say this is nit-picking and small minded but I mention it only in the context of stretching the moon landings to imply that we are outward bound from our home planet and have taken the first step.

I don't see us as likely to leave Earth prmanently. I don't subscribe to the argument which says, 'They said we'd never fly or do this or do that but we did,' because the endgame of that argument is to say that everything is possible and it just isn't. (In my view.) We humans are very drawn to the idea of eternal life (no religion, please) and for some the eternal life of our species means learning to colonize other planets when ours has had it. I simply don't think we will. We do not just live on this planet, we are of it.

Olly

I think I largely agree with this (sadly). Although the human spirit is indomitable we've been nurtured by our environment for so long I think we would gradually start ailing it we were taken from it. It might not affect us for a while but I reckon unless we became something other than entirely human we wouldn't survive indefinitely.

[Dave Lloyd]

P.s I don't mean sadly because I agree with Olly.:-)

[bish]

I think of it in simplistic terms - reaching escape velocity is breaking free of the planet.

[goodricke1]

Of course it was a great acheivement but they took their own atmosphere with them and lived inside earth-replicating suits which they couldn't take off. They never touched the lunar surface, only their suits did. Now you could say this is nit-picking and small minded but I mention it only in the context of stretching the moon landings to imply that we are outward bound from our home planet and have taken the first step.

I don't see us as likely to leave Earth prmanently. I don't subscribe to the argument which says, 'They said we'd never fly or do this or do that but we did,' because the endgame of that argument is to say that everything is possible and it just isn't. (In my view.) We humans are very drawn to the idea of eternal life (no religion, please) and for some the eternal life of our species means learning to colonize other planets when ours has had it. I simply don't think we will. We do not just live on this planet, we are of it.

Olly

Surprisingly negative I'd have to say. Obviously we won't leave in the next 100 years but, say, in the next million years? A million years is a very long time.

[stu640]

Surprisingly negative I'd have to say. Obviously we won't leave in the next 100 years but, say, in the next million years? A million years is a very long time.

Would we still be homo sapiens in a million years? Would it still count as 'us' leaving? A sort of reverse Whig approach to the question!

[ollypenrice]

Surprisingly negative I'd have to say. Obviously we won't leave in the next 100 years but, say, in the next million years? A million years is a very long time.

I don't see this as a negative view, myself. I think it's wonderful that the human race has flowered into being, richly entwined with its environment, and I would expect it to fade as that environment changes. I don't think that advanced life forms last forever. They never have in the past. If you want to last as long as possible it's best to be a microbe trapped inside a rock. I'd rather be human, though!

Olly

[Scott]

Surprisingly negative I'd have to say. Obviously we won't leave in the next 100 years but, say, in the next million years? A million years is a very long time.

I agree with Olly on this one and don't see it as negative at all. It has taken I don't know how long, for us to evolve into a species perfectly suited to our environment. to think we can survive in a completely different environment.... when I say this I don't mean just getting by in an artificial earthlike environ is in my opinion, over optomistic. As for whether we can do it in 1 million years time....I think it'd be difficult for an extinct species to do this 

[D4N]

Well one of the possible solutions to the Fermi paradox is that for intelligent life to make it to development level required for space colonisation is incredibly rare due to some unknown block that we have not encountered yet. A pessimistic view but possible nonetheless.

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[bitnick]

As to the original question, I agree that we have physically "broken free" of our planet if we reach escape velocity.

Biologically, I don't think we can "break free". We could probably create robotic colonies that would "survive" on their own on some other planet (mars comes to mind). Maybe we could even create some DNA-engineered species that would survive on another planet. But those wouldn't be human.

Humans living sustainably (without input from earth) on another planet? I'm very sceptical.

For any of this to happen, we need to prioritize our resources to these hugely expensive projects (in terms of energy and other resources), instead of using them to solve more local problems. We've been living the last couple of hundred years with ever increasing amounts of energy thanks to fossil fuels (millions of years of stored sunlight in an easily transported and very concentrated form!). Now that we've reached peak conventional/cheap oil, the amount of net energy (after extraction) available to us is bound to decrease for the foreseeable future*. This will be a very big hindrance to any sort of major off-planet living!

I also think this ever increasing supply of energy has fooled us into thinking that technology can solve anything. Sure, with an infinite amount of energy and enough time to develop the technology, much can be done (although a lot of the physics we've learnt also teaches us that there are hard limits to what can be done). But technology cannot substitute for energy!

*Sure, there's fracking, but

1) These aren't new reserves, they have been known since the sixties; the only reason they haven't been exploited until know is because they are expensive! It wasn't until the oil price went above ~$100/barrel that they became economically viable. Today, with oil prices at about $60/barrel, the fracking companies are making huge losses. Expensive here means that they take a lot of resources to develop, meaning less net energy is available from them. It means we are scraping the bottom of the oil barrel, so to speak.

2) These sources are very finite. US shale production is predicted to peak around 2020 (by the IEA, no less), simply because there will be no more sites left to exploit, and because decline rates of individual wells are something like 50 %/year.

 

IEA chief economist Fatih Birol says: "In Europe we are facing the risk of the lights going off. This is not a joke."

Maybe the restricted availability of energy is the unknown block that we're just about to encounter? For sure, it's the stumbling block that will keep us occupied for the next few hundred years or more.

[martin_h]

Lets face it if we do ever make it off this planet we will only be going to another in this solar system, and if the reason for going is this planet is ending, then for sure the most likely end is the death of our local star, and if that happens all the planets in our system will suffer.

[damnut]

@Auspom,

Agreed, I don't see the species lasting a million years, we will have trashed the earth one way or another by then. We look aghast at scifi films where invading species use the earth for supplies... That's what we will try to do the moon and mars.

[DaveS]

Well, the average life of a mammalian species is reckoned to be 2 million years or so, our species is currently 200,000 years or thereabouts. Of course we could self-extinct, but if we don't....

There is the question of whether evolution can work on a self-aware organism that can alter its environment to suite itself, I think we are the only current organism that ticks both those boxes.

On the subject of the moon landings, I remember reading that they didn't in fact achieve escape velocity, they only had to reach the earth-moon equilibrium point and let the moon's gravity do the rest.

[Physopto]

We haven't even been further in manned flight than to the Moon a few times. BUT we are already claiming to be able to sell legally bits of other planets to our inhabitants. The human species is arrogant in its stupidity!

https://www.moonestates.com/

https://www.buymars.com/

Are we all nuts?

Derek

[DaveS]

Those gullible enough to part with their money are.

There's no basis in international law for selling bits of other worlds, and those who try to stake a claim will come a (Expensive) cropper.

Edit: This is wandering OT and possibly in danger of the dreaded "P" word.

The only way to break free of our planet would be to break though to the Brane next door. If you know how to do that you're a better man than I.

[goodricke1]

I agree with Olly on this one and don't see it as negative at all. It has taken I don't know how long, for us to evolve into a species perfectly suited to our environment. to think we can survive in a completely different environment.... when I say this I don't mean just getting by in an artificial earthlike environ is in my opinion, over optomistic. As for whether we can do it in 1 million years time....I think it'd be difficult for an extinct species to do this 

In purely practical terms I agree it's unlikely we'll survive another million years, I was speaking more hypothetically that in the unlikely event of us still being around, we should be capable of accomplishing feats which now seem purely science fiction.

Veering OT somewhat, if we are being watched at this moment by an advanced species, can we really say that anything we do on this planet is permanent? Is it not possible at any moment they could intervene and reverse our actions or set us on an entirely different course than would have otherwise prevailed?  

I'll get my coat...

[Physopto]

I don't think that we are going to leave this planet in the conventional way. Not by rockets anyway. Too dependant on old physics. When it happens it will be by some new way less dependant on conventional fuels, we can't carry enough fuel. Science fiction often becomes science fact! Wright bros, rockets, rail guns, Star Trek! We may be on the verge of speeds almost comparable to the speed of light (0.6c).

If we manage to find out what DarkEnergy is it may lead the way to control of gravity, we are trying to detect gravitational waves. Think about it we could not even produce electricity 200 Years ago, not useful electricity. We are fast discovering new physics at an ever quickening rate.

On the other hand we have dictator countries now trying to produce nuclear weapons. It may be the end of us, let's hope we prevail though. I would like to see us get out of our solar system, but it will not happen in my lifetime unfortunately. Like, I suspect most or all astronomers, amateur and professional, we want to know what is out there and how it works.

In the mean time I'll just have to settle for pretty pictures.

Derek