The Astronomy Thread

The way I see it, we either use up our local resources and overpopulate the Earth pushing us to expand, or the advancement in energy production and nano-stuff will make it relatively easy/cheap to undertake such a project. Think the things we could do with fusion power or room temp superconductivity.

I think we're pretty close (100-200 years) from being capable of building aVon Neumann probe. On the other side, if we're able to do that, we'd soon (something like 500k years) have a probe on every planet of our galaxy and that brings me to my previous point : in 13.7 billion years why hasn't someone else built one already ?

Eh, there's plenty of semi-rational explanations for the fermi paradox, including von neumann probes. It's based on assumptions anyway, like "an alien species will have the same desire for exploration/expansion as humans" and "technology will come about naturally." I personally think that there's some specific point in technological progress that each developing civilization eventually reaches prior to interstellar travel that accidentally/instantly destroys the entire species. Like, "oops, I just introduced matter to anti-matter."

Which, btw, if we could get enough of and control the process could potentially accelerate spacecraft to 90%~ the speed of light.

which means absolutely nothing in space explorations. The speed of light is absurdly slow at universal scale

unless we surpass that limit, and i mean surpass it at least by 100 times, the only interstellar colonization process we could hope to achive is reaching the few local systems around us with probes, and MAYBE send a human mission if we find an habitable planet within 20ly. The problem is finding one in that range...that is 0.02% of the galaxy

because beyond that, we are talking about generation long voyages

Very likely the first interstellar travel will be on generational arks... So? Factor in special relativity and you don't even need to quite reach the speed of light to colonize the entire universe eventually. Just because the trip might take 1 or more generations A) Doesn't mean people won't volunteer to do so and B) Doesn't make it an irrelevant speed.

It is an old question and certainly not settled butat this pointI'd say that it seems more likely from a technical standpoint for us to produce permanent artificial habitats than to go and find habitable planets. Shit be just too far away.

Kinkle_sl said:

Very likely the first interstellar travel will be on generational arks... So? Factor in special relativity and you don't even need to quite reach the speed of light to colonize the entire universe eventually. Just because the trip might take 1 or more generations A) Doesn't mean people won't volunteer to do so and B) Doesn't make it an irrelevant speed.

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i think you are seriously understimating the size of the universe

fucker_sl said:

i think you are seriously understimating the size of the universe

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Everything I've said in this thread is firmly backed up by the drake equation and technology that is either existing or well-founded theory. The Drake equation does not necessitate that a civilization travel faster than the speed of light.

yes, but it takes time. Hundreds of years just to scan and recon the new potential planet, thousands upon thousands of years to reach a planet, and hundreds of years to fully colonize it. Non counting that a self isolated colonization process like this would make call for help impossible

sorry but sostenible colonization of exoplanets without FTL technologies are simply scifi stuff

the only theoretical scenario where a self sufficient starship, with enought ppl, equipment and resouces to start a new colony, is sent to a completely isolated new world is if our planet is about to go boom and we gamble an "all in" into this ark

Lithose_sl said:

But aren't there Ion engines now that can continually build speed with a very, very high efficiency rate?

Not asking because I think they will get us to another star. More just curious about whether or not they represent an actual advancement in propulsion that might be explored further for a way to move stuff around in space over long distances.

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Yes, you are right. I thought of the ion drive when I wrote 'we have nothing better' but we still need traditional chemical rockets to take these things out of earth's gravity well, so I just kept it short. In fact the first ion engine we used for a probe was on the Dawn spacecraft that visited Vesta. The engine allowed the probe to leave Vesta and fly toward Ceres and this was the first probe to ever stop and orbit (and not merely flyby) one target before moving to another.

Incidentally, I'm excited to see Ceres in 2015. It'll be the first dwarf planet we visit.

fucker_sl said:

because beyond that, we are talking about generation long voyages

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Well there is one hope. If you can accelerate a vehicle to velocities very close to c, the time dilation will make the trip seem much shorter to the passengers. The problem is, to get significant time dilation, you have to reach velocities something like over 0.9c, which I would imagine would be difficult. At 0.99c, you would be perceiving time at 1/7th the 'normal' rate. (seehttp://en.wikipedia.org/wiki/Lorentz_factor)

Also, if the goal is to preserve humanity, you could send seed ships without people on them, and simply have robots make babies in test tubes once it arrives and 'raise' them to be the colonizers. Perhaps upload data into their heads matrix style. (hey, it's the future)

Torrid_sl said:

(hey, it's the future)

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or simply invent FTL travel

theoretically we could populate the entire universe from this planet, realistically, it'd take hundreds of trillions of Years or longer. say you can travel at a speed of one Light year a day; to get from one side of the- currently- known universe(93Billion light years), it would take 254,794,520.54 years just to TRAVEL from one side of the galaxy to the other.

the milky way, is ~100k light years in diameter and has 200-400 BILLION stars- say 10% have a planet in the habitable zone. so we are only talking 2-4 billion stars with habitable planets. colonizing one star a day would take 5 to 10 million years. PER galaxy we'd run out of PEOPLE before we ran out of STARS in our galaxy to colonize-if we wanted a viable population on each planet. i am thinking 5k-10k minimum per planet.

and we do have rocket engines capable of going fast enough, look up nerva engines - in 1968, the phase 1 - kiwi - and phase 2 phoebos engines were successfully tested and kiwi(phase 1) had 75,000 pounds of thrust-test lasted for 2hrs, Nixon defunded the program though before phase 2 and phase 3 engines were finalized.

phase 3 engines- full size for rockets- were supposed to be rated at 4000MW of power/thrust

the nerva xe system was fully tested- in ~1968ish and had twice the rated impulse(thrust?) of the current chemical engine systems in use at the time.

Well eventually resources will run out on Earth (obviously some before others). This will require resources from the Solar System, which will require more permanent habitation in those regions (early colonies).

One scary thought: Let's say civilization gets hardcore fucked up and we're forced to start over (or start per-electricity). Our society has already devoured all the easy to reach resources, which means if mankind had to "start from scratch", they would be kinda fucked.

It would be pretty incredibly hard to wipe out or knowledge base at this point though, which would give whatever civilization follows ours a pretty big leg up. It's not like it was with past civilizations that were isolated and regional. Barring some sort of catastrophic incident that completely wipes humanity out, they can pick up where we left off and depend/rely on energy sources other than fossil fuels. If humanity does get wiped out, the point then is kind of moot, since it might be hundreds of millions of years before a new intelligent species rises to take our place, if one ever does again. It's not an inevitability.

A lot of these assumptions about the inevitability of contacting another interstellar race are also assuming that technology will at some point allow 100x ftl travel or faster, which would be necessary to travel any real distance on the galactic scale. I don't assume that our current understanding of physics is complete, but it may be that speeds that fast will never be attainable no matter how advanced a species becomes.

Gavinrad_sl said:

A lot of these assumptions about the inevitability of contacting another interstellar race are also assuming that technology will at some point allow 100x ftl travel or faster, which would be necessary to travel any real distance on the galactic scale. I don't assume that our current understanding of physics is complete, but it may be that speeds that fast will never be attainable no matter how advanced a species becomes.

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There's also the assumption that we would even be able to recognize intelligent life.

BurnemWizfyre_sl said:

There's also the assumption that we would even be able to recognize intelligent life.

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We aren't great at this on this planet, so, yeah.

1987_sl said:

The other issue with attaining speeds approaching 0.1c is that hitting even so much as a grain of dust moving at that pace would completely destroy the spacecraft.

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Yeah I always wonder how they plan to deal with issues like this. Sure, assume we can go close to the speed of light. What good does that do when you can't actually do it without blowing up?

They would need to develop some manner of deflector shield technology I suppose.