What if Alpha Centauri has no planets?

[Robert Can't]

Colonists should be Scots, since we are the best at everything, we survive well in hostile terrain, and also we could name the planet Caladan.

I have never heard anything more sensible

Even though this is all about space exploration it occurs to me that is it not also important that we save the world first. With all this global warming the planet might die before we even have a chance to finish a space ship. and if we do launch a spaceship than it will make even more carbon dioxide emissions.

Don't correct me about global warming I’m an expert, a qualified ecologist.

 

[GeoModder]

Close to nothing != nothing , especially in chaotic systems. But in the essential you have a point: probably a rocky planet orbiting Alpha Centauri A or B could have a quasi stable orbit....

If a massive body will influence a chaotic orbit before another more distant and alot less massive body can do so, then essentially 'close to nothing' means nothing.

Mars was never habitable. I hate to break this to all the dreamers ... but Mars has no magnetic core, thus no van Allen belts, thus it is directly exposed to the solar wind, thus it is ... and always has been, and always will be ... utterly hostile to life. Just the regular solar wind would be enough to scrub the surface of all but the hardiest life, and a coronal mass ejection would destroy anything hardy enough to survive that. And no amount of terraforming will ever change it.

A magnetic 'shield' is no absolute requirement for radiation protection. A dense enough atmosphere gives the same effect. And Mars probably had a way denser atmosphere in the early stages of our star system. It did lose it quite fast though due to its small size (quicker cooling of the core) and gravity (to little to hold onto an atmosphere in the long run).

 

[GeoModder]

and if we do launch a spaceship than it will make even more carbon dioxide emissions.

Not to correct you on your qualifications, but I do wonder which of the typical rocket fuel components release CO² after being burned. I thought the residue was mostly water vapor.

 

[Robert Can't]

Not to correct you on your qualifications, but I do wonder which of the typical rocket fuel components release CO² after being burned. I thought the residue was mostly water vapor.

It does not produce mutch. But it does. Its like a car.

 

[Gustavus]

Well, Robert Can't, assuming that the proper fusion technology arrives in the nick of time (that is, before those precious polar bears croak), I think launching more of those gosh darn space ships will be global warming's solution. I think the 25 tons of helium-3 the space shuttle can schlep would be a great solution to global warming and more than enough worth the minute amounts of CO2 emitted. 25 tons of helium-3 would provide the US with its energy needs for a whole year. There are millions of tons of helium-3 on the moon. The solution to global warming? Yes, when (if?) this pesky fusion energy shows up.
http://www.space.com/scienceastronomy/helium3_000630.html

 

[GeoModder]

It does not produce mutch. But it does. Its like a car.

Okay, Provide us with a link about this then. I can't find info on this at a quick glance.
Btw, in my book the typical car emits quite a bit of C0² compared to the fuel it uses, so I'm especially curious on the ratio with rocket fuels, since there's a lot of fuel needed for a single launch.

Well, Robert Can't, assuming that the proper fusion technology arrives in the nick of time (that is, before those precious polar bears croak), I think launching more of those gosh darn space ships will be global warming's solution. I think the 25 tons of helium-3 the space shuttle can schlep would be a great solution to global warming and more than enough worth the minute amounts of CO2 emitted. 25 tons of helium-3 would provide the US with its energy needs for a whole year. There are millions of tons of helium-3 on the moon. The solution to global warming? Yes, when (if?) this pesky fusion energy shows up.
http://www.space.com/scienceastronomy/helium3_000630.html

Fusion power is, after half a century of research, still not viable. Not even in the test fusion reactors returning high-radioactive waste. What you also fail to realize is that fusion power is not the solution for powering your car. Oil will be used as long as the industry doesn't really want to switch propellants for transportation, or as long as it is available of course.
I think its an error to wait for the 'magic fusion' while there are a number of other ways to reduce CO² output today.

 

[r_rolo1]

Most of rockets nowadays burn hidrogen + oxygen.....

 

[Dryhad]

It does not produce mutch. But it does. Its like a car.

If it is like a car, the greenhouse impact would be negligible. After all, space ships don't stay inside Earth's atmosphere anywhere near as long as the average car. And it is my understanding that it is, in fact, not like a car, and does not produce as much (if any) greenhouse gasses. So in terms of environmental impact, it's really trivial.

 

[frekk]

A magnetic 'shield' is no absolute requirement for radiation protection. A dense enough atmosphere gives the same effect. And Mars probably had a way denser atmosphere in the early stages of our star system. It did lose it quite fast though due to its small size (quicker cooling of the core) and gravity (to little to hold onto an atmosphere in the long run).

Nope. Venus has an extraordinarily dense atmosphere, most dense of all the planets, and yet its surface is bombarded with heavy radiation from the solar wind - even despite the powerful reflective action of the sulphuric clouds.

Also one of the reasons why Mars and Venus have the kind of atmospheres that they do is because, without a magnetic field, the solar wind actually blasts the lighter gasses off the planet and out into space. Venus in fact has a tail of gas from the blasting effect that stretches as far as Earth's orbit.

The Venusian ionosphere does produce a weak magnetic field in reaction to the solar wind bombardment, but it is very feeble and affords little protection. This is the mechanism by which atmospheres deflect some of the charged particles, but it is still ultimately through a magnetic field, and is insufficient relative to the kind of magnetic fields possessed by Earth.

If either of these planets ever had magnetic fields like ours, then maybe they could have supported life - but they cannot now, and no planet without a magnetic field can.

 

[Willem]

It does not produce mutch. But it does. Its like a car.

It's not at all like a car. As mentioned they burn Hydrogen and Oxygen, not gasoline. So there's no CO2 created, only water vapour. They're probably the most environmentally sound form of transportation we have today.

 

[Willem]

If either of these planets ever had magnetic fields like ours, then maybe they could have supported life - but they cannot now, and no planet without a magnetic field can.

That's too much of a blanket statement. We don't know for sure whether there is a type of life that can exist in that environment, you're only basing your statement on what we currently know about earth type life. And even here we're finding life forms that thrive under conditions we never would have suspected before.

 

[Gustavus]

GeoModder, I certainly realize fusion technology is decades away - i noted such if you'll take notice - but my point with the helium-3 (and yeah, it wasn't articulated very well) was to refute the idea that exploits in space have no value, as articulated by a few posters. And on the issue of oil... Yes, oil is going to remain a pollutant in whatever industry it's used in, but I'm sure you know that cars certainly aren't the only cause of global warming. Coal much? Nuclear power, even in the form today (not fusion) can conceivably replace much of the coal-dependent processes polluting nations depend on. It's not a fix-all, but it will reduce CO2 emissions, given the will to produce the nuclear plants. And frankly, if the Volt pipe dream works out, we just might be driving electric cars powered by nuclear energy.

 

[GeoModder]

GeoModder, I certainly realize fusion technology is decades away - i noted such if you'll take notice - but my point with the helium-3 (and yeah, it wasn't articulated very well) was to refute the idea that exploits in space have no value, as articulated by a few posters.

Guess I didn't take notice then... and I certainly agree on your second point.

And on the issue of oil... Yes, oil is going to remain a pollutant in whatever industry it's used in, but I'm sure you know that cars certainly aren't the only cause of global warming. Coal much? Nuclear power, even in the form today (not fusion) can conceivably replace much of the coal-dependent processes polluting nations depend on. It's not a fix-all, but it will reduce CO2 emissions, given the will to produce the nuclear plants. And frankly, if the Volt pipe dream works out, we just might be driving electric cars powered by nuclear energy.

My assumption is that if fission power was used to replace all current coal -and oil plants producing electricity for the net, we would run out of uranium sooner then we would run out of oil, not to mention providing energy for electric cars.
And don't get me started on the issue for several millennia thereafter.

 

[frekk]

And even here we're finding life forms that thrive under conditions we never would have suspected before.

A variety of conditions, yes, but not under extreme levels of ionizing radiation. It is too damaging to any sort of highly complex molecules, even inorganic ones. There are a few organisms that can survive a brief, intense exposure, but none that thrive under constant bombardment - not even tardigrades (and their survival to brief, intense radiation depends on being in an inactive state).

 

[r_rolo1]

That does not invalidate chemical energy based ( volcanic vent style ) life that only surface very seldom or never....

 

[GeoModder]

Nope. Venus has an extraordinarily dense atmosphere, most dense of all the planets, and yet its surface is bombarded with heavy radiation from the solar wind - even despite the powerful reflective action of the sulphuric clouds.

Also one of the reasons why Mars and Venus have the kind of atmospheres that they do is because, without a magnetic field, the solar wind actually blasts the lighter gasses off the planet and out into space. Venus in fact has a tail of gas from the blasting effect that stretches as far as Earth's orbit.

The Venusian ionosphere does produce a weak magnetic field in reaction to the solar wind bombardment, but it is very feeble and affords little protection. This is the mechanism by which atmospheres deflect some of the charged particles, but it is still ultimately through a magnetic field, and is insufficient relative to the kind of magnetic fields possessed by Earth.

If either of these planets ever had magnetic fields like ours, then maybe they could have supported life - but they cannot now, and no planet without a magnetic field can.

Well, the Wiki seems to disagree.

It's this snippet in the article that I refer you to:

Dealing with radiation

It is believed by some that Mars would be uninhabitable to most life-forms due to higher radiation levels. Without a magnetosphere, the sun is thought to have thinned the Martian atmosphere to its current state; the solar wind adding a significant amount of heat to the atmosphere's top layers which enables the atmospheric particles to reach escape velocity and leave Mars (effectively boiling off the atmosphere). Indeed, this effect has even been detected by Mars-orbiting probes. Venus, however, shows that the lack of a magnetosphere does not preclude a dense atmosphere. A thick atmosphere will also provide radiation protection for the surface, as it does at Earth's polar regions where aurorae form, so the lack of a magnetosphere would not seriously impact the habitability of a terraformed Mars. In the past, Earth has regularly had periods where the magnetosphere changed direction and collapsed for some time. Some scientists believe that in the ionosphere a magnetic shielding was created almost instantly after the magnetosphere collapsed, a principle that applies to Venus as well and would also be the case in every other planet or moon with a large enough atmosphere.

Bolded for emphasis.

 

[frekk]

It's nonsense.

Venus, however, shows that the lack of a magnetosphere does not preclude a dense atmosphere.

Yes, Venus has a very dense atmosphere of heavy gasses which cannot be blown off by the solar wind ... this does not include hydrogen or oxygen. These are "boiled off" as the article puts it.

as it does at Earth's polar regions where aurorae form

Earth's poles are not exposed to the direct stream. A small portion of charged particles get caught in the magnetosphere's "tail" and wind up, eventually, at the poles. This is just a tiny fraction of the solar wind that ever reaches our ionosphere.

Some scientists believe that in the ionosphere a magnetic shielding was created almost instantly after the magnetosphere collapsed, a principle that applies to Venus as well

Venus' ionosphere does produce a magnetosphere, as noted already. However, it is very insignifigant and does little to stop ionizing radiation from reaching Venus' surface.

More wiki for you:

In 1980, The Pioneer Venus Orbiter found that Venus's magnetic field is both weaker and smaller (i.e. closer to the planet) than Earth's. What small magnetic field is present is induced by an interaction between the ionosphere and the solar wind,[30] rather than by an internal dynamo in the core like the one inside the Earth. Venus's magnetosphere is too weak to protect the atmosphere from cosmic radiation.

http://en.wikipedia.org/wiki/Venus

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 ...

 

[r_rolo1]

Venus atmoshphere has a nice ammount of water.... it look that it forgotted to be blowed away.

 

[GeoModder]

@Frekk: I guess we can only agree to disagree then.

 

[frekk]

Venus atmoshphere has a nice ammount of water....

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

Because of the lack of any moisture on Venus, there is almost no relative humidity (no more than 1%) on the surface, creating a heat index of 450 °C to 480 °C.

http://en.wikipedia.org/wiki/Venus

Unlike Earth, Venus lacks a magnetic field ... Lighter gases including water are continuously blown away by the solar wind

http://en.wikipedia.org/wiki/Atmosphere_of_Venus