The Astronomy Thread

Szlia

Szlia

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Torrid_sl said:
a reason beyond "it's not colonized yet."
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Historically it has been enough of a reason for many (along with: "if we don't know what's there, maybe there are... TREASURES!").

That said, exhaustion of natural resources and/or deterioration of the habitat can be motivators as well. Deterioration of the political climate too. At the apex of cold war, when there were credible reasons to fear nuclear winter, I am sure a one way ticket to a distant habitable planet would have been very appealing.
 
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Torrid

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Kinkle_sl said:
Theoretically, we're already capable of building spacecraft that could potentially reach Alpha Centauri in 50~ years at 1/10 the speed of light (other difficulties aside). We just... don't. Cause the commies'll get us.
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You and Brad vastly overestimate mankind's current technological capabilities and/or underestimate the distances between stars.

The fastest vehicle we have ever sent into space, Voyager 1, would take 72,000 years to reach the nearest star.

The best idea for an interstellar vehicle that we can even think of is a craft powered by detonating many nuclear explosions behind a pusher plate. The amount of energy required to propel a craft to the nearest star within a century would be so massive it could otherwise be used to end man made global warming, or destroy all non microbial life on earth. A craft the mass of the space shuttle impacting the earth at 0.1c would explode at something like 15 times the world's combined nuclear arsenal.
 
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Torrid

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Szlia_sl said:
Historically it has been enough of a reason for many (along with: "if we don't know what's there, maybe there are... TREASURES!").

That said, exhaustion of natural resources and/or deterioration of the habitat can be motivators as well. Deterioration of the political climate too. At the apex of cold war, when there were credible reasons to fear nuclear winter, I am sure a one way ticket to a distant habitable planet would have been very appealing.
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As I mentioned, there is no resource reason to colonize other stars. There are virtually unlimited resources in the solar system in the form of asteroids. Elements that are rare in the earth's crust are common in asteroids. (gold, platinum, iridium, etc)

Escaping political oppression might be one motivation, but once you've colonized a few thousand stars, one of them is bound to be a nicer place to live than starting a new colony from scratch. In fact a new, small colony would likely be politically riskier than a larger established one on top of the non-political risks. What's more likely to end up with a despot: the United States or some seastead in the middle of the ocean created by some eccentric rich libertarian? Jonestown comes to mind. Of course your oppressive government would have to sanction the launch of a seed ship to begin with if not outright contribute to the project as the costs would be rather prohibitive and it's not the kind of thing you could keep secret.
 
Szlia

Szlia

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I was more thinking of things like clean water, arable land, breathable oxygen... and as far as fleeing earth for political reasons, what I had in mind is more something like a country saying 'fuck that noise' because they might end up being collateral damage in a world war so they end up creating New Togo in a galaxy far far away... we are very far in fantasy land with that type of scenario though.
 
Cybsled

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The primary thing that will motivate travel/colonization within our solar system and outside of it will be the same thing that motivated travel throughout human history: Resources, which in turn leads to power/money.
 
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Torrid

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Szlia_sl said:
I was more thinking of things like clean water, arable land, breathable oxygen...
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Water desalination and purification, generating fertilizer, and air purification are things we can do already. They just require energy. With the amount of energy required to send the seeds of civilization to another star system, you could just fix home instead. Of course by the time we could even entertain the notion of colonizing other stars, not polluting earth wouldn't be an issue anyway. You'd be strip mining asteroids in orbit or the moon and not earth. You could put your chemical plants on mars and whatnot. But pollution is really just a matter of money and political will. It's only a problem because we allow it to be one.

Not to mention water ice is abundant in space, you can grow crops without soil, and oxygen is the third most common element in the universe.

Even if you find an earth-like that had life on it for the billions of years needed for an oxygen saturated atmosphere, it would still be virtually guaranteed to not be terribly comfortable for any number of reasons. The surface gravity would likely be different; the atmospheric pressure would likely be different; the mean temperature might be too hot fueling massive hurricanes and other extreme weather; the planet could be in a 'snowball' period with it entirely covered in ice; it might be full of dinosaurs; the days might be 10 hours long or 40 hours long; the oxygen level might be so high that fires consume the land constantly, breathing the air causes oxygen toxicity, and the insects are 2 feet long; the orbit may be so elliptical or the axis so tilted that seasons are extreme; the planet could be orbiting a red dwarf causing the flora to look very alien as it evolved to absorb different wavelengths of light; etc. We are perfectly adapted to this planet because we evolved on it-- finding a planet with an oxygen atmosphere is likely to be rare enough, but finding one with all the parameters of earth would be exceedingly rare. You'd have to have some very good reasons to put up with traveling many lightyears to settle in an inferior environment.

Of course these are all reasons why the Fermi Paradox doesn't persuade me very much. Aliens didn't colonize earth because there was no reason to. In fact there is reason NOT to-- so as not to disturb the natural evolution of life there. Why destroy it just to live there uncomfortably.
 
Brad2770

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Torrid_sl said:
You and Brad vastly overestimate mankind's current technological capabilities and/or underestimate the distances between stars.

The fastest vehicle we have ever sent into space, Voyager 1, would take 72,000 years to reach the nearest star.
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And youre talking about a vehicle launched in 1977. Before the turn of the 20th century, we had motorized vehicles with a top speed of about 45 mph. We now have vehicles that can go 10 times that on a regular basis. We even have extreme vehicles, like the NASA X-43 that can do around mach 10. All of this within 100 years. Youre telling me, that within 200 more years, we couldn't shave a trip time to another star down to 25 years or less?

And for the record, the Helios probe is the fastest man made object.
 
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fucker_sl

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Brad2770_sl said:
And youre talking about a vehicle launched in 1977. Before the turn of the 20th century, we had motorized vehicles with a top speed of about 45 mph. We now have vehicles that can go 10 times that on a regular basis. We even have extreme vehicles, like the NASA X-43 that can do around mach 10. All of this within 100 years. Youre telling me, that within 200 more years, we couldn't shave a trip time to another star down to 25 years or less?

And for the record, the Helios probe is the fastest man made object.
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hmmm....i think current space craft use gravitational acceleration as 99% of their propulsion. They don't have trusting engines like sci spaceships

and gravity has not changed since 1977.

I'm sure we could calculate and use it better now, but even improving it 10 times rispect Voyager-1 thanks to a "mathematical miracle" we would still be thousand+ years away from proxima centauri
 
Brad2770

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I realize that, but just like we advanced from horse and buggy to 450mph jets, I think space travel will have a similar jump. We are still in the horse and carriage phase of space and until the new Rockefeller, Carnegie and Morgan come along to pioneer space travel, it is still going to seem extreme and unrealistic that we could make it to another star.
 
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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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fucker_sl

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Brad2770_sl said:
I realize that, but just like we advanced from horse and buggy to 450mph jets, I think space travel will have a similar jump. We are still in the horse and carriage phase of space and until the new Rockefeller, Carnegie and Morgan come along to pioneer space travel, it is still going to seem extreme and unrealistic that we could make it to another star.
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yes but to advance from horse to jets we had to invent hundreds of technologies in between. So far we are barely at "inventing the wheel" concerning spaceflight

unless we invent some kind of completely new form a propulsion there is not much more improvement in the current technologies. And it was said by nasa scientists, not by a random internet dude like me

one of the tech they are developing is Variable Specific Impulse Magnetoplasma Rocket or Thermal Nuclear Engines. They should improve things. But to reach 0.1c we need a technological breakthrough we cant even imagine
 
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Torrid

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Brad2770_sl said:
And youre talking about a vehicle launched in 1977. Before the turn of the 20th century, we had motorized vehicles with a top speed of about 45 mph. We now have vehicles that can go 10 times that on a regular basis. We even have extreme vehicles, like the NASA X-43 that can do around mach 10. All of this within 100 years. Youre telling me, that within 200 more years, we couldn't shave a trip time to another star down to 25 years or less?

And for the record, the Helios probe is the fastest man made object.
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Well if you want to pick nits here, I'll clarify. Voyager 1 has the fastestheliocentric recessionspeed of any man-made object. It's a little easier to go fast when you're flying into the sun's gravity well instead of away from it.

Alpha Centauri is 4.37 light years away. To get there in 25 years, a craft would have to exceed 0.1748c. 2,000 metric tons (approximate mass of a space shuttle + tanks) traveling at 0.1748c has about 2.8E21 Joules of kinetic energy. That is the energetic equivalent to roughly 670 gigatons of TNT, or 15.5 metric tons of antimatter colliding with 15.5 metric tons of matter, or about 8,450 metric tons of deuterium?tritium fuel consumed in a fusion process. The total world annual energy consumption in 2010 was 5E20 J. A 2,000 ton 25 year trip to Alpha Centauri with 100% efficient engines and instant maximum velocity (impossible, obviously) would require the energy equivalent to 5.6 years of the current annual human energy consumption.

Then assuming space dust doesn't destroy your craft, you have to somehow send a signal back to earth. This is actually an obstacle so significant that one of the first ideas proposed is to send a physical object back home instead of sending a signal. You cannot merely send an omnidirectional radio message back to earth, because the radio waves would quickly fade into the background noise of space due to the inverse square law. So you'd have to develop some kind of focused EM beam and aim it with extreme precision or drop relay devices along the route.

On top of that, your spacecraft would of course be in the Alpha Centauri system for all of a few days before it flew past it. Deceleration and orbiting in the same time frame would be considerably more difficult and require faster velocities and several times the fuel.

All this in 100 years? Not a chance. 200? highly doubt it. Rockets have been around so long that Genghis Khan was using them in warfare in the early 13th century, and we still have nothing better. We'll be sending star probes when we've mastered controlled energy positive fusion, antimatter generation and storage, and antimatter fueled propulsion. By then we'll have hypertelescopes snapping pictures of exoplanets, so people of the future might just wait until the discovery of some sort of interdimensional shortcut instead of creating a relativistic kill vehicle.
 
Lithose

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I know nothing about rockets or propulsion, so this is just a question.

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.
 
iannis

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I think those engines are hypothetical. They should work, but no one has built one. That's the kind of engine they're talking about putting on the manned mission to mars craft isn't it?
 
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fucker_sl

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Torrid_sl said:
Well if you want to pick nits here, I'll clarify. Voyager 1 has the fastestheliocentric recessionspeed of any man-made object. It's a little easier to go fast when you're flying into the sun's gravity well instead of away from it.

Alpha Centauri is 4.37 light years away. To get there in 25 years, a craft would have to exceed 0.1748c. 2,000 metric tons (approximate mass of a space shuttle + tanks) traveling at 0.1748c has about 2.8E21 Joules of kinetic energy. That is the energetic equivalent to roughly 670 gigatons of TNT, or 15.5 metric tons of antimatter colliding with 15.5 metric tons of matter, or about 8,450 metric tons of deuterium-tritium fuel consumed in a fusion process. The total world annual energy consumption in 2010 was 5E20 J. A 2,000 ton 25 year trip to Alpha Centauri with 100% efficient engines and instant maximum velocity (impossible, obviously) would require the energy equivalent to 5.6 years of the current annual human energy consumption.

Then assuming space dust doesn't destroy your craft, you have to somehow send a signal back to earth. This is actually an obstacle so significant that one of the first ideas proposed is to send a physical object back home instead of sending a signal. You cannot merely send an omnidirectional radio message back to earth, because the radio waves would quickly fade into the background noise of space due to the inverse square law. So you'd have to develop some kind of focused EM beam and aim it with extreme precision or drop relay devices along the route.

On top of that, your spacecraft would of course be in the Alpha Centauri system for all of a few days before it flew past it. Deceleration and orbiting in the same time frame would be considerably more difficult and require faster velocities and several times the fuel.

All this in 100 years? Not a chance. 200? highly doubt it. Rockets have been around so long that Genghis Khan was using them in warfare in the early 13th century, and we still have nothing better. We'll be sending star probes when we've mastered controlled energy positive fusion, antimatter generation and storage, and antimatter fueled propulsion. By then we'll have hypertelescopes snapping pictures of exoplanets, so people of the future might just wait until the discovery of some sort of interdimensional shortcut instead of creating a relativistic kill vehicle.
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i love ppl who can write and explain things much better than me
 
Cybsled

Cybsled

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Funnily enough, for all the shit people give the show Defiance, they kinda got the space travel aspect right. They didn't have FTL ships and it took them 5k years to get to Earth. However, they had to slow their ships down as they approached their target. Based on the backstory for the show, as a result of the slowing it took them over 10 years to get from just outside the Kupiter Belt to Earth's orbit, which actually gave human governments time to prepare.

But interstellar travel is practically going to need some type of FTL-type system.
 
Tripamang

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Iannis_sl said:
I think those engines are hypothetical. They should work, but no one has built one. That's the kind of engine they're talking about putting on the manned mission to mars craft isn't it?
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They definitely exist, and have been used/going to be used in quite a few NASA mission.http://en.wikipedia.org/wiki/Ion_engine#Missions

NASA is doing research on FTL travel:http://www.space.com/21140-star-trek...-possible.htmlIf they prove the effect exists we still can't produce enough antimatter to scale it up to a space ship, but it's a great first step.
 
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Well said Torrid.

I think one of the biggest failing we have is our inability to appreciate time, scale and energy costs. They are massive issues when we talk about extra-solar exploration and we are not anywhere close to addressing them really.
 
fanaskin

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The main reason to want to colonize multiple star systems is so the species wouldn't be wiped out by some random solar event, just a fraction of the species on some distant solar system.
 
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Northerner

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Well, *that* is far more feasible.

We don't have the tech yet (understatement of the year) but we can envision a path to being able to send out colony ships with either people on ice or self-sustaining populations. They'd likely take thousands of years to get wherever they were going but this is something we should eventually be able to do if we don't fuck things up too badly locally.

I doubt we'll undertake such a massive project though just to be able to say that there are humans out there somewhere. Who knows however? Certainly not me.
 
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