Fermi paradox - Alex Semenov's classification

[magnemoe]

23 minutes ago, Polnoch said:

 

I not agreed with this conclusion, because New Horizon hasn't goal to have a big delta-v with Sun, and cross  Galaxy with very big speed. Please recall about Voyager program, and about ion/plasma engines(it's not fantastic, and it exist!). I think, It's not difficult to create something, which can cross galaxy during some of millons years - we can use ionic engines, and Obert's maneuvers using Jup, may be, using Sol.

I think, argument about "achieve stars impossible" not correct. May be we'll never achieve it, but not because it is impossible.

Alex Semenov wrote about Greate Filter, but in explanations of his formulas, I think, he made mistake: Greate Filter not only about Swan, but also about Pikes. In pikes, we have P₂~0 - civilizations exist(P₁ = 1), but doesn't create the Wave of Mind. If Create Filter exist, and if it in our future (if it in our Past, we probably live in Swan case), we, our civilization, must be destroyed, and we can't create the Wave, because we will died.

If we'll create the Mars Colony in next years, it may be evidence, proof, about we can create the Wave of Mind by technology reasons.

But may be we live in Crawfish, inside alien's mind zone? May be nearly us is civilization-predator, and other civilizations to be silent, because they was killed by predator or fear of being discovered by Z=1/2 predator?

Also we can live inside mind zone, if we alive... inside computer simulation May be our Universe is simulation on layer of elementary particles? And space around us empty, because it's interesting for persons, who running our simulation?

I think, we need to wait new Scopes - new Europe's 40m, new U.S. in Hawaii, 30m, and Jams Webb. This devices provides us abilities to fix more variables of  Drake's formulas. But founding or not founding O2 planets not permit to us to exclude life, using alternative bio-chemistry (for example, live probably can exist on Titan, Saturn's satellite... It can based not on H₂0)

Could you please explain, who is Rama?

Interstellar probes is some magnitudes easier than interstellar colonies who is capable of seeding more colonies.
it will be expensive even for an level 1 civilization, also if you have some colonies the interest of getting more is likely to be lower.
Worse you might put up the firsts on crappy planets, glory and to secure the species is good enough reasons, however would they be willing to go to an even more crappy planet? No planet and the interest would be even lower, lots of room in the solar system.

As for great filters in the future, see the tread about how humanity can go extinct, it has to be something who pretty much destroy the planet and it has to hit before you have independent colonies on other planet or on asteroids. Worse for ailens who happens to have two planets with life in solar system. Rare but not implausible, put Venus in Mars place is one way, we would probably have bases on it today. 

[PB666]

11 hours ago, Stargate525 said:

Hold on a moment. The reason we've found a lot of stars with that configuration is that a fast, heavy planet close into the star makes it wobble more perceptibly than an earth-sized one. It's a self-selection bias based on one of the ways we find planets.

The biggest problem with the drake equation is that all of its inputs are guesses. I skimmed the beginning of the article, but I personally couldn't wade through the broken English.

That was a few years ago, the problem now is that close objects with short periods are more easily detected in transects, if an object has a period of a year, like earth or 1.5 years like Mars, AND you need to see at least 2 periods to propose and 4 periods to confirm then you potententially have to observe the star for 10 years. That is a problem because the Kepler observatory is a bit crippled (not just a bit, very crippled). We can see small things transcent but we stumble seeing small slow objects transect.

I think it is mute in some regard, smalls stars are long lived but tend to be flare stars, none-the-less have the largest potency to support intelligent life, those stars would have planets in closer orbits with shorter periods. Stars larger than the sun will have shorter lives, with habitable zones further out, and slower periods, but less likely to survive long enough to have intelligent life.

[tater]

49 minutes ago, Polnoch said:

 

I not agreed with this conclusion, because New Horizon hasn't goal to have a big delta-v with Sun, and cross  Galaxy with very big speed. Please recall about Voyager program, and about ion/plasma engines(it's not fantastic, and it exist!). I think, It's not difficult to create something, which can cross galaxy during some of millons years - we can use ionic engines, and Obert's maneuvers using Jup, may be, using Sol.

 

I think I didn't make myself clear. I was merely looking for a lower-limit boundary value for crossing time. I suppose the cheapest (dv wise) real mission would likely be just killing solar orbital velocity around the galactic center (~200-250 km/s), then letting the stars rotate around it as it half-crosses in its highly eccentric orbit around the core.

I was really just putting a lower limit on physically crossing the galaxy.

 

Quote

Could you please explain, who is Rama?

Rama refers to a book by Arthur C. Clarke, Rendezvous with Rama.

[KAL 9000]

I think that habitable planets are semi-rare (1 for every 5-10 stars with planets), but with at least 300 billion stars with planets in the Milky Way, that's 30 billion - 60 billion habitable planets within reach of a good Alcubierrie drive! However, life evolving by chance on a certain planet is extremely rare, probably at a rate of only one time per galaxy. But, I think panspermia is plausible. After all, some microorganisms are extremely hardy. So, if panspermia is correct, life might be as common as being on one out of every three habitable planets! But intelligent life is very rare.

[magnemoe]

1 hour ago, KAL 9000 said:

I think that habitable planets are semi-rare (1 for every 5-10 stars with planets), but with at least 300 billion stars with planets in the Milky Way, that's 30 billion - 60 billion habitable planets within reach of a good Alcubierrie drive! However, life evolving by chance on a certain planet is extremely rare, probably at a rate of only one time per galaxy. But, I think panspermia is plausible. After all, some microorganisms are extremely hardy. So, if panspermia is correct, life might be as common as being on one out of every three habitable planets! But intelligent life is very rare.

Statistic indicate that life is easy, it started shortly after it was possible on earth. Yes it might be very rare but then its rare it started so fast on earth. 
Advanced life took an long time, yes it had to wait to get decent with oxygen first, intelligent life is  recent so so in the same way its statically rare. 
Even intelligence to technical civilization is an long step, humans does civilization well, we are a lot like social insects here. 
An aliens might not be able to organize above tribal level, does not work psychological or even physical as in need to smell the leader regularly. 
This is not an issue during evolution it just show up in that city states or larger organizations are unstable. 
or an predator with no animals who is easy to domesticate. 
 

[fredinno]

On 4/6/2016 at 1:45 PM, PB666 said:

The fact that the universe is very big isn't material, or that our galaxy is very big, is also immaterial. Space travel is not easy, and pretty much half of the habitable galaxy is too far away to view.

No, isn't it hard to see because it's on the other side? I mean, we can see 13 Billion years into the past....

17 hours ago, magnemoe said:

yes O2 is not intelligent life just life. Also agree that keeping an telescope on an planet with O2 for an extended time is far more effective than hunting blind.

But O2 can be made abiotically, and is not a really good indicator for life. O2 + Ch4 is better, since the two burn together, and the two together means life is likely- but both can still be created abiotically, so

On 4/6/2016 at 11:29 AM, KerBlammo said:

I think industrial civilizations are quite rare, and even if they are there we can't detect them.  If there was an Earth like planet orbiting Alpha Centauri we probably wouldn't know it given our available tools.  The Sci-Fi trope of aliens watching "I love Lucy" 50 light years away is not possible given today's technology.  The radio waves are just too weak to be detected across interstellar space.  Sure if we aimed a very powerful transmitter at a point in the sky it might be detected, but we're not doing that, at least not very often.

Life on Earth apparently arose quickly after things settled down enough for the ground to be solid and stuff stopped falling out of the sky in vast quantities. But for billions of years that life was barely more advanced than pond scum.  And once more complex life did arise it did not immediately start constructing TV studios and making and broadcasting sit-coms.  Dinosaurs dominated the planet for tens of millions of years and there is no evidence they were highly intelligent or capable of making the simplest of tools.  

The human species might have been around for the last million or so years but its only in the last few 100 years have we had anything like the technology to announce our presence to any who might be listening (and so far except for a few brief transmissions we have not done so).

So if the Earth is at all typical (and of course thats the still the big unknown) and even if there are billions of Earth like planets supporting life in this galaxy there would still only be a handful of technological civilizations out there and if they are at all like us they aren't talking.

But some alien civilizations will be more advanced, and should thus be easily detectable, as technological growth has so far been accelerating, and an alien civilization even a million years older than us will seem godlike.

On 4/6/2016 at 11:53 AM, PB666 said:

I don't even think simple life is common, it think you have two planets in our systen with a fortuitois star and arrangement of planets that may have tolerated lifes start twice. There are three planets in our habitable zone, two are currently dead. That basically goes to showvthat once life starts there is more than eve chance that it will promptly die. 

I'de like someone to prove me wrong, all ibsee is exoplanet jubilee with each new duscovered followed by, well, no its really just a hot barren planet orbiting and unstable star that probaly does not have an atmosphere and we think it was blown away a few seconds after the star went bright. 

No, it's only Mars and Earth. And even then, Mars is only in the habitable zone if you have a large enough planet that can build up enough of an atmosphere (thus the "conservative" vs "optimistic")

 

On 4/6/2016 at 3:45 PM, Bill Phil said:

We could potentially build a vehicle with about 11.7% C exhaust velocity. It would have to be done centuries from now, yes, but it's not impossible. If we brake with a magsail, then we could use .117C for the cruise to the star. Or .1C, leaving some extra leftover deltaV. We could potentially go slower, allowing us to send generation ships. 

You don't need FTL for interstellar travel. We could, if we so desired, launch a generation ship using NPP within a century. 

And a black hole drive would be even better, and allow interstellar travel in a lifetime (from the perspective of the person inside )

On 4/7/2016 at 8:26 PM, magnemoe said:

If you don't need planets why don't stay in your solar system and save the energy, yes you might do this a few times but not something you continue doing. 
Yes it you are close to the dryson swarm level it start making sense but this has not been detected.

On the other hand we are on the edge of discovering earth like planets, in not to long we will have an decent map, someone who go interstellar will have maps of the actual exoplanets. Its pretty hard to hide planets. 

One part I agree in, why move to an crappy planet

Because we need more resources, so we will eventually have to move out from the solar system.

[fredinno]

 

14 hours ago, KAL 9000 said:

I think that habitable planets are semi-rare (1 for every 5-10 stars with planets), but with at least 300 billion stars with planets in the Milky Way, that's 30 billion - 60 billion habitable planets within reach of a good Alcubierrie drive! However, life evolving by chance on a certain planet is extremely rare, probably at a rate of only one time per galaxy. But, I think panspermia is plausible. After all, some microorganisms are extremely hardy. So, if panspermia is correct, life might be as common as being on one out of every three habitable planets! But intelligent life is very rare.

If the http://www.astrobio.net/news-exclusive/galactic-habitable-zones/ hypothesis is correct, it seriously limits the possibility of complex life- a star with an eccentric orbit will eventually hit the galactic arms and be sterilized. The Sun is lucky, it has a very circular orbit around the galactic center.

It also shows globular clusters and halo stars are probably not good places for life, all forming at the same time and lacking metals.

[PB666]

2 hours ago, fredinno said:

No, isn't it hard to see because it's on the other side? I mean, we can see 13 Billion years into the past....

But O2 can be made abiotically, and is not a really good indicator for life. O2 + Ch4 is better, since the two burn together, and the two together means life is likely- but both can still be created abiotically, so

But some alien civilizations will be more advanced, and should thus be easily detectable, as technological growth has so far been accelerating, and an alien civilization even a million years older than us will seem godlike.

No, it's only Mars and Earth. And even then, Mars is only in the habitable zone if you have a large enough planet that can build up enough of an atmosphere (thus the "conservative" vs "optimistic")

 

And a black hole drive would be even better, and allow interstellar travel in a lifetime (from the perspective of the person inside )

Because we need more resources, so we will eventually have to move out from the solar system.

That conservative zone i consider optimistic, shrink that zone by 80%, that would be conservative. 

[magnemoe]

3 hours ago, fredinno said:

But O2 can be made abiotically, and is not a really good indicator for life. O2 + Ch4 is better, since the two burn together, and the two together means life is likely- but both can still be created abiotically, so

But some alien civilizations will be more advanced, and should thus be easily detectable, as technological growth has so far been accelerating, and an alien civilization even a million years older than us will seem godlike.

No, it's only Mars and Earth. And even then, Mars is only in the habitable zone if you have a large enough planet that can build up enough of an atmosphere (thus the "conservative" vs "optimistic")

Because we need more resources, so we will eventually have to move out from the solar system.

Not sure how the spectral analyze works? Yes o2 can be made other ways than life but not in the amounts you get with life. 
ozone on the other side will indicate plenty of oxygen. 

An earth like or larger planet with an dense atmosphere trapping lots of heat should work well in mars orbit.

Getting more resources is hardly an good reason to go interstellar, going out so you can build stuff not legal in the solar system building code might be
Even this this will require something close to an level 2 civilization, something who should be pretty easy to spot. 
 

22 minutes ago, PB666 said:

That conservative zone i consider optimistic, shrink that zone by 80%, that would be conservative. 

This will put Earth outside it and we have pretty good evidence that Earth support life. 

[Andem]

3 hours ago, magnemoe said:

Not sure how the spectral analyze works? Yes o2 can be made other ways than life but not in the amounts you get with life. 
ozone on the other side will indicate plenty of oxygen. 

An earth like or larger planet with an dense atmosphere trapping lots of heat should work well in mars orbit.

Getting more resources is hardly an good reason to go interstellar, going out so you can build stuff not legal in the solar system building code might be
Even this this will require something close to an level 2 civilization, something who should be pretty easy to spot. 
 

This will put Earth outside it and we have pretty good evidence that Earth support life. 

Depending on your definition of life 

Devils Advocate out...

[PB666]

4 hours ago, magnemoe said:

Not sure how the spectral analyze works? Yes o2 can be made other ways than life but not in the amounts you get with life. 
ozone on the other side will indicate plenty of oxygen. 

An earth like or larger planet with an dense atmosphere trapping lots of heat should work well in mars orbit.

Getting more resources is hardly an good reason to go interstellar, going out so you can build stuff not legal in the solar system building code might be
Even this this will require something close to an level 2 civilization, something who should be pretty easy to spot. 
 

This will put Earth outside it and we have pretty good evidence that Earth support life. 

Nope put mars far out of it and retain the lower boundary.

Here so my original point, for any given starting planet, given its satellites, is star, its surface composition, it gas. The best of these (meaning having alot of surface water) might have a habitable zone in the conservative zone, but for the planets we have observed at a distance, best case scenarios are few and far between, most of these that do not have the right gas and water compositions will have smallish habitable zones because the temperature extremes are too great for life. That zone could be where earth is, it could be closer to Mars, but whereever it is the zone of the planets a is much smaller than the conservative zone and much smaller than the zone in which earth can support life, on average.

We make our assumption based on earth, but as of yet we have not spotted anything close to something that has the surface composition like earth (meaning 70% coverage by water), thats a rather big problem to have to overcome.

Or let me put it like this, from an organic chemistry point of view, which is what i am by training and education,

Talking about life can be laid out like quantum physics lays out the standard model, from a organic chemistry point of view.

Under many conditions you can create simple organic molecules and a slew or random organic molecules, and life can benefit from these and start.
Under many fewer conditions you can have non-living systems systematically producing these molecules as a resource stream that can support life, and life can evolve somewhat
(We can imagine these circumstances at pools that get struck by lightning or the non-thermodynamic products produced in hot pressurized aqueous beds that lie deep under a planet)

Some may call this habitable, I don't, the problem is that under these circumstances life at its simplest levels continually evolves, but then dies out. So you are better off that a circumstance where life starts and then say freezes solid, desiccate, is carbonized by radiation and eventually becomes part of a sediment. But in terms of humans walking over planting a flag and 1000 years living on the surface and breathing the air, nope, your still going to be in a dead zone. You might say, aha but somewhere deep in that planet there is an archabacteria like species that has lived for 5 billion years, that is a living monocellular organism - - - - - - what we know about earth is that the potential energy organic chemistry of life has a high dependency on the allospecific transmission of resources - put simply all life on earth is dependent on other life not of its germ line, that is a major reason it took so long to evolve during the early period. So do you want to say living thing or life, inhabited or habitable, meaning other things can be added to this system and in doing so would turn living into life. So habitable represents a smaller set of planets, planets in which system can partition and share nutrients without have the holosystem does not interrupt and kill off some aspect of the transfer. On earth just about every species can be replaced by something that wanders in to fulfill that species role (confining argument to the organic, things like autoplants and rocket makers do not qualify).

Under a much smaller set of circumstances life starts, there is some photosynthesis, or maybe too much solar radiation, that only a small portion of the planet is permanently habitable, for example the poles of really warm planets or the hot plumes equator of really cold planets, or underwater for planets that have slow rotations where the surface and surface waters constantly freeze and thaw as part of its diurnal cycle. We could actually settle and inhabit these places, with technologies - a habitable planet with fractuous preexisting life, and no intelligent or sentient life.

Under a very tiny set of circumstances where a planet has water, has a moon, a solid core surrounded by a viscous amorphous region that produces a magnetic field, has about 50 to 90% coverage with water, very close to the amount of insolance that the earth recieves, and over a very tiny set of time frames might we find sentient life.

If you take any planet and say, aha, it can support life under some circumstance, and you take only the stars were that planet can support life IOW

A.Given a rock that might support life
B. Given a star that might allow that particular rock to support life
C1. There is a confined set of orbits and eccentricities in which that rock will support life sometime in that stars existence

Given all the possible C1.
C2. There is even a more confined set that will continuously support life over much of the stars life time

Given all possible C2.
C3. There is a much more confined set that would be habitable from our perspective

Given all possible C3
C4. There is a much much more confined set that could potentially develope sentient life.

 

 

 

 

 

 

 

[fredinno]

5 hours ago, magnemoe said:

Not sure how the spectral analyze works? Yes o2 can be made other ways than life but not in the amounts you get with life. 
ozone on the other side will indicate plenty of oxygen. 

https://www.sciencedaily.com/releases/2014/10/141003092259.htm

It can be formed from the breakdown of Co2 (hard due to double bond)

or H2O (easy due to single bond).

http://www.astrobio.net/news-exclusive/oxygen-in-exoplanet-atmospheres-could-fool-search-for-life/

Quote

 

5 hours ago, magnemoe said:

Getting more resources is hardly an good reason to go interstellar, going out so you can build stuff not legal in the solar system building code might be

If you start building dyson spheres, you begin to run out of resources fairly quickly.

6 hours ago, PB666 said:

That conservative zone i consider optimistic, shrink that zone by 80%, that would be conservative. 

The conservative zone is considered the "conventional" habitable zone of the habitable area of Earth-like aqua planets.

50 minutes ago, PB666 said:

Under a much smaller set of circumstances life starts, there is some photosynthesis, or maybe too much solar radiation, that only a small portion of the planet is permanently habitable, for example the poles of really warm planets or the hot plumes equator of really cold planets, or underwater for planets that have slow rotations where the surface and surface waters constantly freeze and thaw as part of its diurnal cycle. We could actually settle and inhabit these places, with technologies - a habitable planet with fractuous preexisting life, and no intelligent or sentient life.

Under a very tiny set of circumstances where a planet has water, has a moon, a solid core surrounded by a viscous amorphous region that produces a magnetic field, has about 50 to 90% coverage with water, very close to the amount of insolance that the earth recieves, and over a very tiny set of time frames might we find sentient life.

Why do you need a moon for intelligent life? The climatic changes will be a problem, but intelligent species should be able to move from point a to B once they run out of resources, and the climate changes. The magnetosphere can take care of itself, provided the planet is big enough.

Also, http://www.space.com/12800-alien-life-desert-planets-habitable-zone.html Desert Planets that have very low amounts of water apparently increase habitability of planets enormously (water is a GHG, and increases albedo when an ice), allowing life on a planet with 170% of Earth radiation on the hot limit of habitability, and 72% of Earth radiation on the cold side- and larger planets with more GHGs can yet expand that region.

This is why some Solar System habitable zone maps have an "optimistic" zone all the way out to Ceres, as a Super Earth could sustain life at that distance, even intelligent life, if the conditions are right.

Also: http://www.iflscience.com/space/alien-worlds-most-stars-have-planets-habitable-zone

[PB666]

10 hours ago, fredinno said:

No, isn't it hard to see because it's on the other side? I mean, we can see 13 Billion years into the past....

But O2 can be made abiotically, and is not a really good indicator for life. O2 + Ch4 is better, since the two burn together, and the two together means life is likely- but both can still be created abiotically, so

But some alien civilizations will be more advanced, and should thus be easily detectable, as technological growth has so far been accelerating, and an alien civilization even a million years older than us will seem godlike.

No, it's only Mars and Earth. And even then, Mars is only in the habitable zone if you have a large enough planet that can build up enough of an atmosphere (thus the "conservative" vs "optimistic")

 

And a black hole drive would be even better, and allow interstellar travel in a lifetime (from the perspective of the person inside )

Because we need more resources, so we will eventually have to move out from the solar system.

You are trying to prove my point. 13.7 billion years ago there was no life, 8 billion years ago there probably was no life, and the life that exists 13.7 light years from our current position in space is immaterial to the question

CH4 in the presense of SO4, a product of FeS04 oxidation can be utilized by certain archeaobacteria. If high levels of Methane existed while 02 levels rose, the earth might not now have an atmosphere.

CH4 + 3O2 = 2H20 + CO2 (Kaboom). Lived down the road from a house where Methane leaked under the house, someone flipped the light switch and pretty much the house was scattered about a 1/4 mile circle

You can bet as soon as O2 levels rise, methane disappears fast, those sulfate loving bacteria on the sea floor. There are also bacteria that reverse the process they can methane out of simple sugars, scavenging the oxygen for metabolism.

Yes, the person inside wearing virtual reality goggles and engaging in science fantasy. Black holes the right size don't just walk into your solar system and say hello, in the life of the universe the space-time frequency of a black hole the right size has a probability near absolute zero.

A critical point gets overlooked while we are handwaving about the Earth while we hand-wave, the earth is what it is, not something else it might have been.
This arguement seems silly but then lets go about predicting how much Net water will be released from Antartica in the Next 200 years, or how far down the greenland Ice sheet will melt.

If you take Earth say 24,000 years ago and moved it out say 10 million kilometers (1/15th of its current a) in its orbit and then ask the question.

1. Does the current ice age end.
2. Do humans advance to start cultivating Secale cereale, Einkorn both transition grains to Triticum aestivum
3. Does Bos taurus primagenious get domesticate
4. Does rice farming begin in India and Burma and move into China (Probably not, the current rice farming areas would be at too high of an elevation). Does wet rice farming begin.

Now we can ask the same question

1. Life gets started on Earth, and earths lignite forests grow, and are knocked over by a few asteroid events locking most of the carbon into coal beds for millions of years
2. Snow ball earth occurs
3. Never exits or exits say 500 million years later. 
Twice in earths history the freeze condition has happened, if earth was just a little cooler, it might not have exited.

We actually do not know enough about the earth to model its paleoclimatology going back 3.3 billion years under variant circumstances of a.
The obvious reply is that we don't know enough to say that the zone couldn't be bigger, and I would answer, the earth is what it is, not something else. We are here and we, after extensive searching have not seen another earth, so the answer might be other than its bad telescopes and interpretations.

Imagine a snow ball earth just 10 degrees cooler. Snow ball earth occurs. The albedo increases. The ice layer thickens
The tides slow down, amplitudes fall, the moon stops its long radial march.
The earths rotation stops slowing down
The dynamo inside the earth slows down
The amorphous region outside the solid core gets less energy begins to crystalize in places, solidfy
Earths magnetic field begins to disappear
Oxygen is lost, Sublimation of the ice occurs, further cooling the surface. Eventually small ponds of water.
Because we lost oxygen there is no oxidant left to burn Carbon locked in Oxygenation event carbon sinks, CO2 cannot rise and warm things up.
The sun finally ages enough to heat up the ice to melt it; however its too late, the atmosphere is too thin to support life.

Maybe some of those lifeless earths are the result of a life process that just stopped because the long-term was simply not OK.

 

 

 

 

 

 

 

 

 

 

Edited April 8, 2016 by PB666

[fredinno]

1 hour ago, PB666 said:

 

CH4 + 3O2 = 2H20 + CO2 (Kaboom). Lived down the road from a house where Methane leaked under the house, someone flipped the light switch and pretty much the house was scattered about a 1/4 mile circle

Yeah, that's why if trace amounts of Methane are in the atmosphere, something's replenishing it. Possibly life.

[Aethon]

1 hour ago, PB666 said:

Imagine a snow ball earth just 10 degrees cooler. Snow ball earth occurs. The albedo increases. The ice layer thickens ....(Snip)

I'm not so sure about this scenario.

IMO snowball is much easier to recover from than runaway greenhouse, as evidenced by the Earth actually doing it.  The step you're missing is volcanic action reintroducing green house gasses like carbon dioxide back into the atmosphere.  Since the sea is mostly frozen, the CO2 isn't able to be reabsorbed into to the hydrological cycle by the sea, therefore building up CO2 concentration in the atmo. raising the temperature and melting the snowball earth.

[magnemoe]

1 hour ago, fredinno said:

https://www.sciencedaily.com/releases/2014/10/141003092259.htm

It can be formed from the breakdown of Co2 (hard due to double bond)

or H2O (easy due to single bond).

http://www.astrobio.net/news-exclusive/oxygen-in-exoplanet-atmospheres-could-fool-search-for-life/

Yes, this is why I wondered if they could get the faction of gasses in atmosphere, is it just an trace element or 20% of it. 
If your atmosphere is 20% oxygen from breakdown of water you have an problem
On the other hand Earth oxygen levels was low up until 500 million years ago, think the oxygen reacted with the ground and bound up iron and other stuff

 

2 hours ago, fredinno said:

If you start building dyson spheres, you begin to run out of resources fairly quickly.

Yes, but this is not very realistic Swarms are and works just as well, even if more boring
 

[PB666]

1 hour ago, Aethon said:

I'm not so sure about this scenario.

IMO snowball is much easier to recover from than runaway greenhouse, as evidenced by the Earth actually doing it.  The step you're missing is volcanic action reintroducing green house gasses like carbon dioxide back into the atmosphere.  Since the sea is mostly frozen, the CO2 isn't able to be reabsorbed into to the hydrological cycle by the sea, therefore building up CO2 concentration in the atmo. raising the temperature and melting the snowball earth.

CO2 is highly attracted to cold water, this is the reason for the poly-decadal carbon sink that so frustrated climate scientist. Atmosheric CO2 from volcanos is a turnover phenomena, and a large contributer is the subduction zones with deep benthic stores of unoxidized carbon, if earth were to lose a large portion of its O2 then that carbon output in ash would not be oxidized to CO2, it would simply end up as complex carbon such as CN or SCN or soot. If earth were to lose its Oxygen by magnetic field loss, then you have a completely different earth, it would not be earth any more, it would be like the difference between neo-Mars and mars 100 million years after most of its atmosphere is stripped away. The subduction zones would eventually lose their detrital sources of carbon and stable carbon would end up in other minerals.

The evidence of the earth actually doing it comes from an Earth that is in its current orbit, that is to say there is no proof or certainty that if you moved the orbit 10 million miles further out, that it would recover.

 

1 hour ago, fredinno said:

Yeah, that's why if trace amounts of Methane are in the atmosphere, something's replenishing it. Possibly life.

CO2 is replinished from the Methane from life and geological sources, this splits hairs because methane can be trapped in psuedo shale from the Hadean and Early Archean Eras, it can also be from shales from Archean and later eras. The difference is that from the later periods the other organics will spike (such as propane, butane, and benzene).

[Bill Phil]

5 hours ago, magnemoe said:

Yes, this is why I wondered if they could get the faction of gasses in atmosphere, is it just an trace element or 20% of it. 
If your atmosphere is 20% oxygen from breakdown of water you have an problem
On the other hand Earth oxygen levels was low up until 500 million years ago, think the oxygen reacted with the ground and bound up iron and other stuff

 

Yes, but this is not very realistic Swarms are and works just as well, even if more boring
 

There was a mass extinction event caused by too much oxygen... I think over 500 million years ago...

[magnemoe]

4 hours ago, PB666 said:

You are trying to prove my point. 13.7 billion years ago there was no life, 8 billion years ago there probably was no life, and the life that exists 13.7 light years from our current position in space is immaterial to the question

CH4 in the presense of SO4, a product of FeS04 oxidation can be utilized by certain archeaobacteria. If high levels of Methane existed while 02 levels rose, the earth might not now have an atmosphere.

CH4 + 3O2 = 2H20 + CO2 (Kaboom). Lived down the road from a house where Methane leaked under the house, someone flipped the light switch and pretty much the house was scattered about a 1/4 mile circle

You can bet as soon as O2 levels rise, methane disappears fast, those sulfate loving bacteria on the sea floor. There are also bacteria that reverse the process they can methane out of simple sugars, scavenging the oxygen for metabolism.

Yes, the person inside wearing virtual reality goggles and engaging in science fantasy. Black holes the right size don't just walk into your solar system and say hello, in the life of the universe the space-time frequency of a black hole the right size has a probability near absolute zero.

A critical point gets overlooked while we are handwaving about the Earth while we hand-wave, the earth is what it is, not something else it might have been.
This arguement seems silly but then lets go about predicting how much Net water will be released from Antartica in the Next 200 years, or how far down the greenland Ice sheet will melt.

If you take Earth say 24,000 years ago and moved it out say 10 million kilometers (1/15th of its current a) in its orbit and then ask the question.

1. Does the current ice age end.
2. Do humans advance to start cultivating Secale cereale, Einkorn both transition grains to Triticum aestivum
3. Does Bos taurus primagenious get domesticate
4. Does rice farming begin in India and Burma and move into China (Probably not, the current rice farming areas would be at too high of an elevation). Does wet rice farming begin.

Now we can ask the same question

1. Life gets started on Earth, and earths lignite forests grow, and are knocked over by a few asteroid events locking most of the carbon into coal beds for millions of years
2. Snow ball earth occurs
3. Never exits or exits say 500 million years later. 
Twice in earths history the freeze condition has happened, if earth was just a little cooler, it might not have exited.

We actually do not know enough about the earth to model its paleoclimatology going back 3.3 billion years under variant circumstances of a.
The obvious reply is that we don't know enough to say that the zone couldn't be bigger, and I would answer, the earth is what it is, not something else. We are here and we, after extensive searching have not seen another earth, so the answer might be other than its bad telescopes and interpretations.

Imagine a snow ball earth just 10 degrees cooler. Snow ball earth occurs. The albedo increases. The ice layer thickens
The tides slow down, amplitudes fall, the moon stops its long radial march.
The earths rotation stops slowing down
The dynamo inside the earth slows down
The amorphous region outside the solid core gets less energy begins to crystalize in places, solidfy
Earths magnetic field begins to disappear
Oxygen is lost, Sublimation of the ice occurs, further cooling the surface. Eventually small ponds of water.
Because we lost oxygen there is no oxidant left to burn Carbon locked in Oxygenation event carbon sinks, CO2 cannot rise and warm things up.
The sun finally ages enough to heat up the ice to melt it; however its too late, the atmosphere is too thin to support life.

Maybe some of those lifeless earths are the result of a life process that just stopped because the long-term was simply not OK.

Ice age has been standard the last few million years, no reason to think we are not set for another ice age in a 1000 years (human will interrupt it but that is OT)

Snowball earth happened, probably multiple times before 500 million years ago, sun was cooler but the atmosphere was a lot of co2, probably methane and other stuff too, pressure was probably higher, less had escaped and probably lots of co2 would later be bound.
The explanation I have heard for ending the snowball is that all ground and most water is covered by ice so lite co2 get absorbed, few plants alive so co2 levels build up, temprature start to rise, ice melt, co2 get absorbed and you get an new round. 
If much colder earth would probably have to wait som 100 million years for the cambium revolution.

[PB666]

3 hours ago, magnemoe said:

Ice age has been standard the last few million years, no reason to think we are not set for another ice age in a 1000 years (human will interrupt it but that is OT)

Snowball earth happened, probably multiple times before 500 million years ago, sun was cooler but the atmosphere was a lot of co2, probably methane and other stuff too, pressure was probably higher, less had escaped and probably lots of co2 would later be bound.
The explanation I have heard for ending the snowball is that all ground and most water is covered by ice so lite co2 get absorbed, few plants alive so co2 levels build up, temprature start to rise, ice melt, co2 get absorbed and you get an new round. 
If much colder earth would probably have to wait som 100 million years for the cambium revolution.

Colder earth means longer event, means more likely to happen, means risk of a non-recoverable event more likely.

[YumonStudios]

On 4/8/2016 at 0:34 PM, insert_name said:

pretty sure titan has rivers of liquid methane, we can probably make a dam and use hydroelectric power but with methane

The question is coming up with a turbine that can stand those temperatures.

On 4/8/2016 at 0:38 PM, Aethon said:

I'm not so sure about this scenario.

IMO snowball is much easier to recover from than runaway greenhouse, as evidenced by the Earth actually doing it.  The step you're missing is volcanic action reintroducing green house gasses like carbon dioxide back into the atmosphere.  Since the sea is mostly frozen, the CO2 isn't able to be reabsorbed into to the hydrological cycle by the sea, therefore building up CO2 concentration in the atmo. raising the temperature and melting the snowball earth.

Also, the lower amount of photosynthesis makes it easier to recover from a snowball.

On 4/8/2016 at 2:02 PM, magnemoe said:

Yes, this is why I wondered if they could get the faction of gasses in atmosphere, is it just an trace element or 20% of it. 
If your atmosphere is 20% oxygen from breakdown of water you have an problem
On the other hand Earth oxygen levels was low up until 500 million years ago, think the oxygen reacted with the ground and bound up iron and other stuff

 

Yes, but this is not very realistic Swarms are and works just as well, even if more boring
 

You can get lots of O2 from breakdown of water, which is why Scientists are careful about judging habitability based only off O2.

And swarms still need an enormous amount of matter.

http://www.popularmechanics.com/space/deep-space/a11098/could-we-build-a-dyson-sphere-17110415/

Quote

Making a full Dyson Swarm that would catch nearly all of the sun's rays, though, would require dismantling perhaps the entire inner solar system—Mercury, Venus, Earth, and Mars.

A "dyson Bubble" made of statites are lowest in mass, but need an absurdly low density of less than 0.7 g/m2, compared to paper's 80 g/m2. It's questionable whether it would work.