What if Alpha Centauri has no planets?

[GeoModder]

If we want to find life (or habitable worlds) out there, we should be looking for powerful magnetospheres ... these are probably the chief requirement. Liquid water etc is probably a consequence of the conditions produced by that phenomena. I also have a feeling that we will be probably be able to detect the effect of a powerful magnetosphere, before we can detect small planets like ours. The solar wind's interaction with the magnetosphere does produce radio emissions ...

Erm... Jovian planets are also likely to produce powerful magnetospheres, so it's not exactly a foolproof method of detecting habitable worlds, nor life.

I do concede a strong magnetosphere is a requirement for a longterm (geological timescales) viable biosphere, but for shorter term habitation (human timescales) dense atmospheres should suffice. Even Earths magnetosphere is severely toned down for a while every few hundred millennia on average, and its inhabitants as a species survive that.

 

[r_rolo1]

Yes, all of 0.002%; 500 times less than us, 15 times less than even Mars.

You forgot that Venus has 92 atm of pressure.... you need to rescale that for absolute quantities and take in account the size of the planet as well, not percentages. if you make the math , you'll see that Venus has far more water than Mars and only a degree of magnitude less than earth....

Yup, Venus has less water than earth, but given a average temperature of 450 ºC for ( as far as we know ) hundrets of millions of years, that is not exactly strange. But I really can't see a sizable ionic wind effect in that.... like I said, higher temperature,= higher average speed of molecules = more lighter molecules out.....

 

[Kranden]

whos to say other life is even intelligent or even communicable. It's possible dominant life on other planets are not mammals or something plantlike, Insectlike, aquatic fish or even a creature that is intelligent and communicates with subtle movements or smells.

Most creatures do not use language its possible we are one of the few ones in the universe who do, who knows.

 

[Wodan]

whos to say other life is even intelligent or even communicable. It's possible dominant life on other planets are not mammals or something plantlike, Insectlike, aquatic fish or even a creature that is intelligent and communicates with subtle movements or smells.

Most creatures do not use language its possible we are one of the few ones in the universe who do, who knows.

You mean like... a communal "hive" mind, based upon fungus spread quite literally across an entire planet? It doesn't even have a concept for lannguage, let alone communication... there are no other "minds" in its history so there would be no need to communicate. (ps "language" is a subset of "communication") Such a creature would have to learn the very concepts of communication and language from the humans it encounters. The initial "get to know you" period could be quite traumatic for the humans.

 

[r_rolo1]

You mean like... a communal "hive" mind, based upon fungus spread quite literally across an entire planet? It doesn't even have a concept for lannguage, let alone communication... there are no other "minds" in its history so there would be no need to communicate. (ps "language" is a subset of "communication") Such a creature would have to learn the very concepts of communication and language from the humans it encounters. The initial "get to know you" period could be quite traumatic for the humans.

Somehow that plot sounds familiar....

I think the problem is far worse.... Just look at the dificulties that we have to understand phants and dolphins languages ( both seem to use sonic ideograms )..... of if they simply see the world in a completely diferent fashion ( I wonder if we would understand easily if we received a 4-D "pages" communication in radio ..... ).

And of course , both us and them would need to consider the others worthy of communication. We don't discuss philosophy with dogs or iguanas.....

 

[GeoModder]

We don't discuss philosophy with dogs.....

You'd be surprised what some dog owners do to their pets.

 

[frekk]

Erm... Jovian planets are also likely to produce powerful magnetospheres, so it's not exactly a foolproof method of detecting habitable worlds, nor life.

That's true .... gas giant magnetospheres are very powerful, actually ... I should instead say, we should be looking for powerful magnetospheres occuring in the absence of gas giants.

but for shorter term habitation (human timescales) dense atmospheres should suffice

Dense atmospheres like Venus tend to be inhospitable for other reasons. One side effect of such dense gasses is that they create a very powerful greenhouse effect, as seen on Venus. We require a specific mix of gasses for breathing as well, mostly made up of the lighter gasses, which will be boiled off in the absence of a magnetosphere such as ours (so even terraforming is out of the question, unless somehow a magnetosphere could be created). Not to mention that the resultant pressure is too high for most of our machines, let alone for our bodies. Even if our bones did not break, and even if we were just breathing our regular mix of air, at 92 atmospheres, it would prove lethal (oxygen toxicity, nitrogen narcosis, etc) because it is too concentrated. Anything over 2 atm of oxygen (we normally breathe 0.21 atm because the air is 21% oxygen) is lethal within minutes - just seconds at 4 atm - and at 92 atmospheres of pressure, we'd be breathing oxygen at over 19 atm!!!

 

[r_rolo1]

You'd be surprised what some dog owners do to their pets.

That's lecturing, not discussing... Discussing would imply that the dog responded and the owner would understand what the dog meant

@frekk

I think that high atmosphere life would be sustainable in Venus.... atleast Sagan calculations showed that it was viable to seed it with unicelular algae ( his idea was to reduce the surface temperature by using them for reducing both incident light and by consuming greenhouse gases ( CO2, H2O ).... Could work in theory )

 

[frekk]

( his idea was to reduce the surface temperature by using them for reducing both incident light and by consuming greenhouse gases ( CO2, H2O ).... Could work in theory )

If you somehow managed that, then the atmosphere wouldn't be dense anymore and it would just blow off. Or, if it was somehow still the same density, the pressure would be so high as to induce instant oxygen toxicity (not to mention that 92 atm is about 1350psi ...). It's kind of a catch-22 without a magnetosphere.

 

[GeoModder]

Dense atmospheres like Venus tend to be inhospitable for other reasons.

I of course meant dense like in bearable to life as we know it.

A Venus -or jovianlike atmosphere I would call compressed.

 

[r_rolo1]

If you somehow managed that, then the atmosphere wouldn't be dense anymore and it would just blow off. Or, if it was somehow still the same density, the pressure would be so high as to induce instant oxygen toxicity (not to mention that 92 atm is about 1350psi ...). It's kind of a catch-22 without a magnetosphere.

If the temperature got below 300ºC the atmospheric CO2 would start combining with the oxides of the surface rock to give Carbonates ( just like it happens on Earth ..... ), thus reducing pressure and the percentage of greenhouse gases. The idea was not a complete conversion of the atmosphere, but simply lower the temperature enough to the equilibrium between CO2 and carbonates to shift towards the solid form.

 

[Magma_Dragoon]

By the time we are ready to send a ship to another star system, we might well have the ability to make an artificial magnetic field around a planet. We could set up the shield generator in a lightly defended outpost on the forest moon of Endor.

Venus lost most of its water to ultraviolet light. The uv light breaks up water into H+ and OH- ions. The H+ ions are swept away by solar wind, and the OH- ions bonded with sulfur dioxide to form sulfuric acid. There could have been life on Venus at one time in the past, because stars get hotter as they age. The sun's temperature increases by 10% every billion years.
I'd like to smash Mercury, Venus, and Mars together into one planet replacing the current Mars.

 

[Magma_Dragoon]

Oops double post. Piece of crap bbs!

 

[r_rolo1]

Venus lost most of its water to ultraviolet light. The uv light breaks up water into H+ and OH- ions. The H+ ions are swept away by solar wind, and the OH- ions bonded with sulfur dioxide to form sulfuric acid.

Sorry, but that is phisically impossible..... at least in the scale you're talking about . And it is chemically impossible as well.

 

[Wodan]

Sorry, but that is phisically impossible..... at least in the scale you're talking about . And it is chemically impossible as well.

You took him seriously? I would have thought the reference to "Endor" and "smashing" planets together to make one bigger, more perfect planet, might have been a clue.

 

[r_rolo1]

^^Well, there is one scientist that proposed seriouly to smash all the planets and make a sphere enclosing the sun .... so I've seen worse

 

[Wodan]

^^Well, there is one scientist that proposed seriouly to smash all the planets and make a sphere enclosing the sun .... so I've seen worse

Yeah, I know. I read Ringworld, and there was also a STAR TREK: TNG episode.

The main problem with that theory is that it would require materials science way beyond anything we have now. We would have to somehow magically transmute the normal stuff of planets (rock and minerals) into this super material that could stand up to the required tensile strength.

 

[r_rolo1]

The material strength would need to be of the same order of the cable for the Space Elevator if we opted for a statite constelation instead of a solid sphere , so in theory if we had enough raw materials ( which we don't have ) we could do it .

P.S In SMAC The Planet, after the fusion with the human minds , appears in the end message making a Dyson sphere

 

[Wodan]

The material strength would need to be of the same order of the cable for the Space Elevator if we opted for a statite constelation instead of a solid sphere , so in theory if we had enough raw materials ( which we don't have ) we could do it .

Yeah, it definitely would take a huge amount of raw materials. Of course, if you have the technology to do this in the first place, you probably have the technology to transport a couple of planets from neighboring star systems. That then begs the question why bother, of course.

At some point I suppose it might be possible to simply create matter from nothing. Probably as a side effect of the process of creating antimatter.

 

[r_rolo1]

We can always borrow some Hidrogen from the sun and to use the inevitable Carbon byproduct of Fusion for the materials , but I can't even imagine a way of removing matter from the Sun easily...

And in the end, why bother? It is far easier to send people to other star systems than to have all this work