Earth Like planet around Proxima Centauri?

RobertDyck · 2016-08-26 11:49:21

"Who are you?"
"What do you want?"

The Shadows have been here long before humanity crawled out of the primordial ooze, and will be here long after you're gone. The Shadows believe that races can only grow stronger through chaos and conflict so drive younger races to war with one another.

From the TV series "Babylon 5": Shadows

RobertDyck · 2016-08-26 14:39:29

Yea Ok. So something more serious. I'm saying if there is well developed life on an alien planet, it could be dangerous. Even if there are no malevolent sentient species, disease and animals could be very dangerous. Viruses could not infect us; the chance of a virus working on any life from our planet is would be less than the most ridiculous thing you could think of. However, bacteria or parasites could eat you.

The most benevolent environment we could hope for could be proto-Earth. In fact, Mars could be the most benevolent. Oxygen is produced by life, but if there is native life, it could be dangerous. A very warm water world with CO2 atmosphere with nitrogen, methane and ammonia? Primordial Earth had that. Could you live there?

Void · 2016-08-26 20:13:49

Since no one else answered, A-Void will answer.

Proxima b would be aged. I also think that a tidal locked planet may have a strange CO2 cycle. If we imagine a ice cap on the dark side miles high, we can suppose the level of cold from distance from its star, altitude, and being on the dark side. So, even on Earth it has almost gotten cold enough for dry ice. So, I imagine CO2 sequestered in that ice cap. But that could be OK, it will cycle with the presumed melting and evaporation of the glaciers of that ice cap. But Venus has enormous amounts of CO2, which I presume would be locked in rocks, if the planet were not so hot. So, in spite of the CO2 sequestering nature of the ice cap, I guess you could have CO2 in the atmosphere. Actually Mars works that way, doesn't it? Except for the volumes we want, and the air pressure we want.

I am inclined to think that world would not have an Ozone layer. Therefore the preference for your location would be on the dark side near the terminator, where hopefully warmer winds prevailed.

I am presuming that this is a first settlement, and that the planet has not been terraformed.

So, you would be in a warm place with about ~1bar pressure. You would have wind power. You could probably get CO and O2 from the atmosphere in small quantities.

Your location would be improved if there was a body of water, preferably a sea nearby, where part of that sea was exposed to the U.V. flux on the day side.
I am guessing that an organic sea foam would wash up on the shores in significant quantities. I expect it would be synthesized in the water by U.V. on the day side from available chemicals.

I presume that your settlers are willing to use machines, and bio-engineering.

Obviously you could grow green plants perhaps in a cave with artificial lights, and an atmosphere which best suited them. Presumably that could also be your home. Wind would power it.

But you would want to get the most with the least effort. So, I suggest that if you could bio-engineer a plant like organism, such as fungi to eat CO or the presumed organic sea foam on the sea shore, and to extract the small amount of O2 from the atmosphere, perhaps you could have fruits from Mushrooms, on the sea shore.

Here is an interesting link suggesting the possibility:
http://www.yesmagazine.org/issues/a-res … e-the-gulf

I suspect that fungi originally habituated the sea shore on the early Earth.

The fungi would have to exist on meager Oxygen, and eat a meager supply of sea foam and CO from the atmosphere, and perhaps Methane and Ammonia?

Not sure if the O2 will survive exposure to Methane and Ammonia, maybe it would.

Tides would not be likely to be huge, but storm generated waves could be. So perhaps you would like a seashore protected by a emerged sandbar, such as is often present on the east coast of the USA.

Your mushrooms might be engineered to have more nutrients, and I would hope protein.

I presume you also live by a stream of drinkable water.

But how do you breath? The schemes for Mars could be employed, minus the need for a pressure suit.

Beyond that perhaps a artificial organ which could Oxygenate your blood. Perhaps your lungs would still exhale CO2.

But your specification of Ammonia suggests irritation to the eyes and lungs. Methane? I don't know.

It would be nice for your settlers to be able to go outside without mask, helmet, or suit for a lengthy period of time to work their mushroom farms, see the stars, and aurora, and work on their windmills.

That's the best I have for now.

Last edited by Void (2016-08-26 21:12:48)

Tom Kalbfus · 2016-08-27 00:34:10

Why wouldn't the world have an ozone layer?
I know of no reason that ozone couldn't form. Ozone freezes at -192.5 C and liquefies at 119.5 C.
I don't know if it would have an ice cap that was miles high unless it was on dry land.

Void · 2016-08-27 01:09:38

I'm having a strange night, so I will reply now.

Mars and Venus do not have significant Ozone. Robert specified an atmosphere of N2, CO2, Ammonia, and Methane.

I think that CO2, Ammonia, and Methane would react with any Ozone formed, and destroy it.

Should the mix be different, say N2 with a pinch of CO2 and a sufficient water vapor content, lets say a humid troposphere, then the U.V. might very likely turn it into a N2/O2 atmosphere, and it would do it without life existing on the planet. This could generate an Ozone layer as well. However, it is thought that a solar flare could destroy the Ozone layer, so it would have to rebuild. Until the rebuild, the daylight side of the planet would be relatively hostile to life on the surface in the "Light".

Therefore for the day side, I recommend full scale covered cities where the inhabitants could still live with relative comfort until the event corrected itself. I did not specify for a full civilization however, so I figured out what would be the best deal for a first settlement, where they could have what they needed, and have relative safety.

As for the ice cap, it seems you may be cherry picking. You cannot assume that the ice cap will be entirely over open water. Our Antarctica is not. And the plateau of Antarctica is "Miles" high. Approximately 2 miles high.

We know that during the last ice age the continental shelves were near exposure. That water then was locked up in north and south ice sheets. If you know that Proxima b will have approximately ~.75 times as much solar energy as Earth, then you can model Earth to guess about it. Move the Earth 1/2 way to Mars so that it has about that warming. You can anticipate that water from the oceans will end up in Antarctica.
I have read that the Troposphere at the poles is about 4.3 miles high. That is probably the limit of how high the vapor could "Try" to pile snow.
I am sure that the rate of deposition would slow down quite a bit before the ice piled up to 4.3 miles. In the Earth model, however we have not yet factored in the higher gravity, or the thermal difference. On your side, the higher gravity of Proxima b would likely cause glaciers to drain faster, putting a greater restraint on the possible thickness of an ice cap.

Against you however, is the fact that Antarctica has a summer of up to 6 strait months which warms it a bit. Proxima b's dark side can be presumed to be eternally (Sort of, eternity is a long time) in the dark of night and an "Eternal" winter. This will stiffen the ice.

In your favor is the notion that if ice is piled high enough that pressure helps to liquefy it's base. That would make the glaciers flow faster to a degree, but then again once you get to the incline of a glacier, you are loosing altitude, and therefore pressure, so I am not sure how much ice pressure is going to help.

Presuming that Proxima b had a different profile such as that of Mars, High Southern Hemisphere (The sun side), and what looks like an ocean basin in the Northern Hemisphere (The dark side) might work out different as I expect more of a very thick "Ice Pack" over water, and less or no "Grounding" of the ice cap. It would "pancake" over the water.

Good night.

Last edited by Void (2016-08-27 01:27:05)

RobertDyck · 2016-08-27 04:21:22

The theory is that planets have CO2 and N2 gas due to geology. These gasses are part of the material the planets formed from. If these elements were part of more complex minerals, those minerals were decomposed by the extreme heat of the planet's core or mantle, then were released as gas by volcanoes.

Ultraviolet light (UV) is part of sunlight, when that strikes O2 in the atmosphere, some O2 (molecular oxygen) is converted to O3 (ozone). Ozone absorbs UV much more readily than O2, and UV will break down O3 back into O2. It reaches an equilibrium based on the intensity of UV, and amount of O2. I think it's dependant on partial pressure of O2, but the O2-O3 equilibrium occurs in Earth's upper atmosphere. Ozone blocks all UV-C and most UV-B, so UV just doesn't reach the lower atmosphere. UV is required to form ozone, that's why ozone only exists in the upper atmosphere.

Mars does have some ozone. UV can break down CO2 into CO and oxygen; Mars does have some oxygen. Because Mars has a tiny bit of oxygen in its atmosphere, its upper atmosphere does have a tiny bit of ozone. However, because of the extremely thin atmosphere and extremely low concentration of O2, the concentration of ozone is even more extremely thin. There isn't enough ozone in Mars atmosphere to block UV-C. Most UV-C and UV-B make it right through to the surface.

Most planets start with water. Again it's left over from the material that formed the planet. If hydrogen was part of more complex minerals such as clay or gypsum, which do occur in comets and carbonaceous chondrite asteroids, the core and mantle will break down those minerals. Then water is released by volcanoes as steam.

UV will break down water in the upper atmosphere into monoatomic hydrogen (H) and hydroxyl (OH). Some will recombine back into water. Some CO2 will break down. Some "C" from CO2 and "H" from water will combine to form CH4 known as methane. So an atmosphere rich with CO2 and with significant water will form methane. There won't be significant ozone to block UV because a CO2 atmosphere won't have much O2.

Similarly, NH3 could form. That's ammonia. However, N2 is much more difficult to split. It requires lightning to form ammonia. And yes, here on Earth there is a shower of ammonia with every lightning strike. That ammonia is consumed by plants as nitrogen fertilizer. I could give the chain of chemical reactions, but it's enough to say lightning produces a rain of nitrogen fertilizer.

Primordial Earth had a thick CO2 atmosphere like Venus. It also had N2, in fact more N2 than it does today because plants have converted some of the N2 into protein and DNA. And all forms of life. CO2 dissolved into Earth's ocean, creating a weak acid called carbonic acid. That helped dissolve minerals releasing calcium and magnesium into ocean water. That calcium and magnesium combined with dissolved CO2 to form minerals calcite and dolomite, which precipitated out as limestone. So most of Earth's thick CO2 atmosphere became limestone.

For billions of years Earth had a CO2/N2 atmosphere, with small amounts of methane and ammonia, and just trace amounts of oxygen. Primitive single celled organisms called archaea thrived in this. Then a new organism evolved called cyanobacteria. That produced oxygen. From perspective of archaea, this was an environmental disaster. Oxygen poisoned anaerobic archaea. Oxygen reacted with and broke down most of the methane and ammonia.

Venus has an atmosphere of 95.something% CO2. Mars has an atmosphere of 95.something% CO2. The Viking 2 lander measured 95.32% CO2, but modern landers and rovers have shown that fraction of a percent changes with weather. On Earth weather is dominated by water, but on Mars weather is dominated by CO2. Scientists tell me Earth started with an atmosphere as thick as Venus has today, and it was 95.something% CO2. So based on the three terrestrial planets with an atmosphere in our solar system, I assume that is a result of planet formation. After Earth's thick CO2 atmosphere was converted to limestone, it left Earth with an atmospheric pressure about equal to what we have today. But it was still CO2/N2. I think it's reasonable to assume a planet orbiting a star in the terrestrial ecozone (aka Goldilocks zone), if it has an atmosphere and water, will be similar to primordial Earth.

Tom Kalbfus · 2016-08-27 09:23:05

Proxima gives off very little UV except when it flares I suppose. So what do you think? Is there life already there, or do we have something we can terraform? Proxima is an energy source. So if Proxima b doesn't have an ozone layer, but Proxima doesn't give off much UV anyway, perhaps it doesn't matter much. Seems to me that traveling 4.25 light years to live on the frozen dark side of a tidally locked planet doesn't make sense. Seems like we would have to device some economical means for crossing interstellar distances. A linear accelerator that is 4.25 light years long with one end matching the velocity of our Solar System and the other end matching the velocity of Proxima, there would be 4 tunnels each one 100 meters wide, to accommodate a Subjective travel time of 3.54 years for accelerating at 1-g for half the distance and 1-g for the other half. The linear accelerator would recover the energy put into the craft's acceleration, when it decelerates, two tunnels would be for traveling, the other two would be for construction and maintenance. Probably would start with one accelerator at Sol and the other at Proxima. Probably it would be build out of Oort cloud material between the stars. You would robots that could construct copies of themselves out or native cometary material, you would need starships that can accelerate to 1% of the speed of light.

Void · 2016-08-27 16:54:46

I am going to argue for an upgrade of the assessment of the quality of Proxima b.

First of all I am going to pull out an old argument that perhaps was used for Mercury, when it was thought it was a tidally locked world. The terminator. But in this case if we argue for the existence of an atmosphere, we can presume particulates in that atmosphere to aid in the scattering of light. I am also going to speculate that red light will be absorbed more than longer wave light. Some human eyes can see in moonlight, I am fair at it, I can almost see colors like green, I believe sometimes.
So, for this twilight zone, (Oooooh!) we could hope to be at a location where you can see well enough to walk around. This would be on the dark side of the terminator, but just close enough so that light scattered from the atmosphere would light up the area to the limits of the human eye to see. This by itself will reduce the harmful U.V., by simple attenuation. Further, since the light scattered would have first traveled somewhat horizontally through the atmosphere, the atmosphere may actually filter out some wavelengths of U.V.

Atmospheric quantity may also help, even without a strong Ozone layer. There are claims that the dead sea air being in a depression and so a somewhat thicker atmospheric column, filters out some of the UV-B, due to the extra CO2, and particulates from the dead sea itself in the air. I don't know what it would do for shorter wavelength UV. So, if a depression with a similar type "Sea" in it were present, perhaps that would be a good location to live.

Being in a shadow of such a depression just sunward of the terminator might be useful. Or of course in the shadow of a mountain.

And it would seem that in the case of a deficiency of Ozone, a deep layer of sea water may filter out many harmful types of U.V. and allow only the visible violet, and UV-A to get through, and apparently there are photo life forms that can use those wavelengths.

So, there is some upgrade for an optimistic potential.

So, you might be able to have an enduring biosphere of microbes in the oceans/seas, under a layer of water, and you might have areas of remediation for UV in twilight areas while allowing for unassisted human vision.

Probably you would still want to monitor the UV flux and have alerts, and have protective gear like goggles and sunscreen and protective clothing which you would use when appropriate.

As for the atmospheric mix, I am going to suppose that Nitrogen and Argon would emerge from a volcanic worlds deep reservoirs, even in the event that in early days, the original atmosphere had been swept away. (I believe that the dark side ice cap might protect many things during that phase anyway, if the planet were tidally locked).

As for CO2, I would think that the planet would use that gas as a last resort. Not that the planet is smart, but that it would have a negative feedback loop, where if the planet were too cold for rivers because the atmosphere was too thin, it would then build up Nitrogen, and Argon, and as a last resort CO2 to make the atmosphere thick enough for rivers. The rivers would then limit the further build up of atmosphere.

That is according to recent dialogs I have read on how things supposedly work.

As for non-biological Oxygen, if the atmosphere built up enough for rivers, then that would indicate that the atmosphere had significant moisture in it.
If it did, and there was no Ozone layer or a weak Ozone layer, Photolysis would generate Oxygen, and Hydrogen, and the Hydrogen would tend to float away into space. And if there were then Oxygen in the atmosphere without excessive Ozone depleting chemicals in the atmosphere, we could think that an Ozone layer would develop.

END.

Last edited by Void (2016-08-27 17:14:46)

GW Johnson · 2016-08-28 18:36:42

There is a very serious problem in this discussion, having to do with the difference between observation and inference. It puts all of you in the position of arguing how many angels can sit on the head of a pin.

There are two and only two things actually "known" about this Proxima Centauri planet: (1) its mass is poorly known to be about 1.3 times that of Earth, with error bars exceeding a factor of 2 to 3, and (2) its orbital period about its star is 11 days (known to about 10 or 20%).

All the other claims (and I do mean ALL of them!) are inferences made from these data and this-or-that theory or model. Considering the pedigree of the various models used to make those inferences, all the claims about this planet are nothing but bullshit! And that's being charitable.

The "Goldilocks zone" calculation is based upon not only the presence of an atmosphere about this exo-planet, but an Earthlike atmosphere. Bullshit!

If that model worked in our own solar system, then Venus would be a hot humid swamp, and Mars would resemble Canada. Neither is anywhere close to true. We already know that the gas species identity overwhelmingly affects the greenhouse effect that it has. We know NOTHING about any putative atmosphere about Proxima Centauri b, or even that it has one!

We do not NOT know this is a rocky planet at all! That is based on our solar system as a model, with small inner rocky planets and huge outer gas giants. It's already known to be a bad model: almost all the systems we have detected show huge planets very close to their star. The odds of an exoplanet system resembling ours seem to be about 1 to 3 in several thousand. So why is 1.3 Earth masses rocky? Bullshit!

I've seen claims of "tidally locked". Bullshit! That's traditionally based on our moon and Mercury. However, we found Mercury not to be tidally-locked, and no other moon I know of has been found to be tidally-locked. Therefore, this is a bad theory. Stupid thing to be basing inferences on. Bullshit!

1.3 Earth masses +/- factor 2 to 3; orbital period 11 days +/- around 10-20%. All else is BULLSHIT!

Reporters who publicize this stuff are completely ignorant of both science and math. The scientists who publish these results are driven by publish-or-perish, in an environment where observation is not newsworthy or citable, while sensational inference is newsworthy (and therefore citable).

My friends, you need to turn up the gain on your bullshit meters! Way up!

GW

Last edited by GW Johnson (2016-08-28 18:39:34)

RobertDyck · 2016-08-28 19:09:37

Yea, I was going to say we need more data. Everything is guess work. In fact exoplanets found so far have far more variation that scientists or even fiction authors ever guessed. I'm hoping Keck or one of the other telescopes that can directly image an exoplanet will give us a view of this one. At least some spectra data that will tell us if it has an atmosphere, and if so what gasses.

GW Johnson wrote:

I've seen claims of "tidally locked". Bullshit! That's traditionally based on our moon and Mercury. However, we found Mercury not to be tidally-locked, and no other moon I know of has been found to be tidally-locked.

Actually Ganymede, Callisto, Io, and Europa are all tidally locked. That's all 4 Galilean moons. Amalthea is the next Jovian moon in terms of size, and closest to the planet; Amalthea is also tidally locked. As well as Titan, Iapetus, Rhea, Dione, Tethys, Enceladus, Mimas, Janus; but not Hyperion, Phoebe. The largest moon of Uranus is Titania; it's tidally locked. The largest moon of Neptune is Triton; it's tidally locked too. I haven't checked the others. It appears to be a factor of gravity of the parent body and proximity.

But yea, we're just guessing. I'm hoping Proxima b is not tidally locked, but we have no idea.

Void · 2016-08-28 22:08:09

I actually have been interested in non-tidally locked worlds myself, but Proxima Centauri is a very tiny star, even in the category of "M"/"Red Dwarf" stars.

I am aware of three ways it might not be tidal locked.

One theory about why Mercury and Venus have the spins they do is that they interact with each other.

Another has it that for Venus, the wind causes the planets spin. It is claimed that if it had a atmosphere like Earths, it would spin 10 times as fast as it does now. If I understand the idea in my way, it would be that cooler dense air falls from the night side, and imposes a friction on the surface (Mountains also), in one direction. It is falling towards the sun, but of course the gravity of Venus holds on to it. Similarly, hotter air from the day side "Floats" away from the suns gravity, being displaced by the cooler air from the night side, and presumably applies torque to the planet in the same direction. But this "Theory" makes me wonder then why Mercury is not tidally locked.

Going with the "Wind" notion, it is believed that such a world would rotate once at a rate of weeks or months. (Of course worlds further out may not risk tidal locking at all).

So, to me that would be a very interesting world as well.

And of course there is the notion that these planets were hit by objects that made them spin.

https://en.wikipedia.org/wiki/Proxima_Centauri_b

Because of the previous complaint, I will quote quite a lot of the article:
Quote:

Characteristics[edit]
Mass, radius and temperature[edit]
The apparent inclination of Proxima Centauri b's orbit has not yet been measured. The minimum mass of Proxima b is 1.27 M⊕, which would be the actual mass if its orbit were seen edge on from the Earth, producing the maximum Doppler shift.[1] Once its orbital inclination is known, the mass will be calculable. More tilted orientations imply a higher mass, with 90% of possible orientations implying a mass below 3 M⊕.[15] If the planet has a rocky composition and a density equal to that of the Earth, then its radius is at least 1.1 R⊕. It could be larger if it has a lower density than the Earth, or a mass higher than the minimum mass.[6] The planet has an equilibrium temperature of 234 K (−39 °C; −38 °F).[1] This puts it in the habitable zone of its parent star.
Host star[edit]
The planet orbits a (M-type) red dwarf star named Proxima Centauri. The star has a mass of 0.12 M☉ and a radius of 0.14 R☉.[1] It has a surface temperature of 3042 K [16] and is 4.85 billion years old.[17] In comparison, the Sun is 4.6 billion years old [18] and has a surface temperature of 5778 K.[19] Proxima Centauri rotates once roughly every 83 days,[20] and has a luminosity about 0.0015 L☉.[1] The star is rich in metals, something not normally found in low-mass stars like Proxima. Its metallicity ([Fe/H]) is 0.21, or 1.62 times the amount found in the Sun's atmosphere.[5][note 1]
The star’s apparent magnitude, or how bright it appears from Earth's perspective, is 11.13.[21] Even though it is the closest star to the Sun, it is not visible to the unaided eye from Earth because of its low luminosity.
Proxima Centauri is a flare star that undergoes occasional dramatic increases in brightness and high-energy emissions because of magnetic activity[22] that would create large solar storms, possibly irradiating the surface of the exoplanet if it does not possess a strong magnetic field or a protective atmosphere.
Orbit[edit]
Proxima Centauri b orbits its host star every 11.186 days at a semi-major axis distance of approximately 0.05 astronomical units (7,000,000 km; 5,000,000 mi), which means the distance from the exoplanet to its host star is one-twentieth of the distance from the Earth to its own host star, the Sun.[1] Comparatively, Mercury, the closest planet to the Sun, has a semi-major axis distance of 0.39 AU. Proxima Centauri b receives from its host star about 65% of the amount of radiative flux that the Earth receives from the Sun. However, because of its tight orbit, Proxima Centauri b receives about 400 times more X-ray flux than the Earth does.[1]
Habitability[edit]

Artist's conception of Proxima Centauri b, with Proxima Centauri and the Alpha Centauri binary system in the background
See also: Habitability of red dwarf systems
The habitability of Proxima Centauri b has not been established.[23][24] [11] Depending on the volatile reservoirs and the rotation rate of the planet, 3D global climate models and theoretical arguments can be contemplated.[24][25]
The exoplanet is orbiting within the habitable zone of Proxima Centauri, the region where, with the correct planetary conditions and atmospheric properties, liquid water may exist on the surface of the planet. The red dwarf host star, with about an eighth of the mass of the Sun, has a habitable zone between ∼0.0423–0.0816 AU.[1]
Even though Proxima Centauri b is in the habitable zone, the planets habitability has been questioned and is not settled because of several potential hazardous physical conditions. For one thing, the exoplanet is close enough to its host star that it might be tidally locked.[26][27] If the planet's orbital eccentricity is 0, this could result in synchronous rotation, with one blazing hot side permanently facing towards the star, while the opposite side is permanently dark and freezing cold.[28][29] Scientists think that some habitable regions, if they exist, would be confined to the region in between the two extreme areas, referred to as the terminator line, where the temperatures might be suitable for liquid water to exist on such a planet.[27]
Proxima Centauri b's orbital eccentricity is not known with certainty, only that it is below 0.35[30] – potentially high enough for it to have a significant chance of being captured into a 3:2 spin-orbit resonance similar to that of Mercury.[31] The European Southern Observatory estimates that if water and an atmosphere are present, a far more clement environment would result from such a configuration, with average temperatures similar to those on Earth.[30][25] A large portion of the planet may be habitable if it has an atmosphere thick enough to transfer heat to the side facing away from the star.[27] If it has an atmosphere, simulations suggest that the planet could have lost about 1 ocean's worth of water due to the early irradiation in the first 100–200 million years after the planet's formation. Liquid water may be present only in the sunniest regions of the planet's surface either in an area in the hemisphere of the planet facing the star or in a tropical belt (3:2 resonance rotation).[24][25] Water retention is the biggest obstacle for planet b's habitability.[32] The planet may be within reach of telescopes and techniques that could reveal more about its composition and atmosphere, if it has any.[11]

Interestingly, the mass of 1.27 is a minimum. I have seen other articles that suggest that it could be as high as 2.0.
This article seems to allow for even more, if I am not reading it wrong.

For Robert, encouragement. I am quoting from towards the end of the above quote:

Proxima Centauri b's orbital eccentricity is not known with certainty, only that it is below 0.35[30] – potentially high enough for it to have a significant chance of being captured into a 3:2 spin-orbit resonance similar to that of Mercury.[31] The European Southern Observatory estimates that if water and an atmosphere are present, a far more clement environment would result from such a configuration, with average temperatures similar to those on Earth.[30][25] A large portion of the planet may be habitable if it has an atmosphere thick enough to transfer heat to the side facing away from the star.[

This is a very interesting sub-quote:

If it has an atmosphere, simulations suggest that the planet could have lost about 1 ocean's worth of water due to the early irradiation in the first 100–200 million years after the planet's formation.

I would imagine that the larger the planet is, the longer it took to either become tidally locked or locked into a 3:2 resonance. So, a large spinning planet, would supposedly have a better possibility to have a robust magnetic field during that 100-200 million years. (On second thought, I don't know). It's a good question. Does a larger planet take longer to go to tidal locking or the 3:2 ratio, from the original spin it had?

I though the greatest danger of loss of atmosphere was the magnetic qualities of the star when it was young. Perhaps I have something more to learn on this.

But you are probably right GW, its good to put restraints on how far speculation goes.

Last edited by Void (2016-08-28 22:58:07)

Tom Kalbfus · 2016-08-28 23:23:19

If Proxima b is a water world, it need not be tidally locked. All we really know about it is its mass, it could be an Earth mass of mostly water for all we know.

GW Johnson · 2016-08-29 10:10:31

Rocky world. Rock + ice world. Water world. Gas planet. Mixes of all these concepts. All are possible. It could also be something we have never imagined before. We just don't know. And that was my point.

The tidal locking thing appears to be more complex than just masses and dimensions. There are also disturbing forces that may or may not be present, which act to break the lock. That stuff is a little outside what I am familiar with. Wasn't familiar with so many moons being tidal-locked (thanks RobertDyck).

Was more familiar with the planets: I remember how surprised the astronomers were to find out Mercury was not tidally-locked some decades ago. The resonance thing with Venus may be the disturbing force that broke the lock. Or maybe something else did it, we just don't know.

The shape of the planet my have something to do with it: our moon is slightly egg-shaped, pointing the bulge toward us. It was a lot closer to the Earth at the time of its formation. Not sure what's cause and what's effect here.

GW

Antius · 2016-08-29 19:01:15

Tom Kalbfus wrote:

Proxima gives off very little UV except when it flares I suppose. So what do you think? Is there life already there, or do we have something we can terraform? Proxima is an energy source. So if Proxima b doesn't have an ozone layer, but Proxima doesn't give off much UV anyway, perhaps it doesn't matter much. Seems to me that traveling 4.25 light years to live on the frozen dark side of a tidally locked planet doesn't make sense. Seems like we would have to device some economical means for crossing interstellar distances. A linear accelerator that is 4.25 light years long with one end matching the velocity of our Solar System and the other end matching the velocity of Proxima, there would be 4 tunnels each one 100 meters wide, to accommodate a Subjective travel time of 3.54 years for accelerating at 1-g for half the distance and 1-g for the other half. The linear accelerator would recover the energy put into the craft's acceleration, when it decelerates, two tunnels would be for traveling, the other two would be for construction and maintenance. Probably would start with one accelerator at Sol and the other at Proxima. Probably it would be build out of Oort cloud material between the stars. You would robots that could construct copies of themselves out or native cometary material, you would need starships that can accelerate to 1% of the speed of light.

Tom, as always interesting. But why do your ideas always involve unfathomably large mega-structures? Do you honestly believe that a 4 light-year (16,000 billion mile) long mass driver is the most practical means of reaching the nearest star? Are there even enough materials in our entire solar system?

Last edited by Antius (2016-08-29 19:04:12)

Tom Kalbfus · 2016-08-30 08:13:18

Antius wrote:

Tom Kalbfus wrote:
Proxima gives off very little UV except when it flares I suppose. So what do you think? Is there life already there, or do we have something we can terraform? Proxima is an energy source. So if Proxima b doesn't have an ozone layer, but Proxima doesn't give off much UV anyway, perhaps it doesn't matter much. Seems to me that traveling 4.25 light years to live on the frozen dark side of a tidally locked planet doesn't make sense. Seems like we would have to device some economical means for crossing interstellar distances. A linear accelerator that is 4.25 light years long with one end matching the velocity of our Solar System and the other end matching the velocity of Proxima, there would be 4 tunnels each one 100 meters wide, to accommodate a Subjective travel time of 3.54 years for accelerating at 1-g for half the distance and 1-g for the other half. The linear accelerator would recover the energy put into the craft's acceleration, when it decelerates, two tunnels would be for traveling, the other two would be for construction and maintenance. Probably would start with one accelerator at Sol and the other at Proxima. Probably it would be build out of Oort cloud material between the stars. You would robots that could construct copies of themselves out or native cometary material, you would need starships that can accelerate to 1% of the speed of light.
Tom, as always interesting. But why do your ideas always involve unfathomably large mega-structures? Do you honestly believe that a 4 light-year (16,000 billion mile) long mass driver is the most practical means of reaching the nearest star? Are there even enough materials in our entire solar system?

We are not limited to just our Solar System to find the materials to build it, there are rogue planets between the stars, judging by the occurrence of low mass stars compared with high mass stars, one can project that rogue planets are even more common than main sequence red dwarf stars like Proxima Centauri, and since I don't want to disfigure star systems by mining out orbiting planets, we can use interstellar planets instead, and I'm pretty sure that with a billion star probes capable of reaching 1% of the speed of light and then slowing down again, we can search an entire cubic light year of space and detect rogue planets within that space above a certain mass. A star such as Proxima Centauri has 127 times the mass of Jupiter, so how many rogue planets of Jupiter mass and less are floating around in Interstellar space? I'm pretty sure there are quite a few.

The first step would be to build 4 billion star probes using local material in our Solar System, send them out to the four cubic light years between Sol and Alpha Centauri, and search out those spaces for rogue planets, after we find some, we mine them for the material for building a linear accelerator, and once one is constructed, we can travel to Alpha Centauri by accelerating all the way.

JoshNH4H · 2016-08-30 08:54:11

Tom-

I don't know why you're using that "4 cubic light years between Earth and Proxima Centauri" number, but seeing as you've repeated it twice I think it bears mentioning that it's not correct.

Space in our part of the galaxy is more-or-less flat, which means that the shortest distance between any two points is the straight line drawn between them. In the case of Proxima Centauri this line is 4.3 light years long. This line is the only thing that could definitively be said to be "between" Sol and Prox. This line, like all other lines, has a volume of 0.

In order to get a volume, you would need to specify some kind of allowable range of deviation from this line. If your range of deviation is "any path from Sol to Prox" then the space "between" them is comparable to the size of the observable universe.

You seemed to have assumed an acceptable range of "within sqrt(1/pi) light years" [cylinder with a cross-sectional area of 1 square light year] without justifying such a value or even mentioning that you had done so.

Seeing as you surely do not intend for your linac to be a physical structure, what's going to keep it in place as it exerts a force on a craft moving through it?

I'd also like to point out that there's a huge difference between a particle accelerator and your proposed linac. Specifically, the difference is about 35 orders of magnitude in the mass you're accelerating.

Tom Kalbfus · 2016-08-30 16:35:42

JoshNH4H wrote:

Tom-
I don't know why you're using that "4 cubic light years between Earth and Proxima Centauri" number, but seeing as you've repeated it twice I think it bears mentioning that it's not correct.
Space in our part of the galaxy is more-or-less flat, which means that the shortest distance between any two points is the straight line drawn between them. In the case of Proxima Centauri this line is 4.3 light years long. This line is the only thing that could definitively be said to be "between" Sol and Prox. This line, like all other lines, has a volume of 0.
In order to get a volume, you would need to specify some kind of allowable range of deviation from this line. If your range of deviation is "any path from Sol to Prox" then the space "between" them is comparable to the size of the observable universe.
You seemed to have assumed an acceptable range of "within sqrt(1/pi) light years" [cylinder with a cross-sectional area of 1 square light year] without justifying such a value or even mentioning that you had done so.
Seeing as you surely do not intend for your linac to be a physical structure, what's going to keep it in place as it exerts a force on a craft moving through it?
I'd also like to point out that there's a huge difference between a particle accelerator and your proposed linac. Specifically, the difference is about 35 orders of magnitude in the mass you're accelerating.

We could always use antimatter, something the size of what I'm talking about could produce an appreciable amount of antimatter which could power some starships, but what I'm talking about is mass transit to the stars, this won't be the first generation of starships, the first generation will likely be capable of traveling at 1% of the speed of light, the second generation can travel at 10% of the speed of light, the third can go up to 95% of the speed of light. Antimatter is dangerous, it might not be for the masses, a tiny bit can destroy a city, it is 100 times as destructive as a thermonuclear bomb, and you need that kind of energy if you do it with rockets. With lasers you need a fantastic degree of precision, and you need to trust in the effort back home, you have no means of communicating back with the people running the beam projector, especially if you need that beam to slow down. If you don't use antimatter, you need an absurd amount of physical infrastructure to get you close to the speed of light, I figure the best sort of infrastructure is the kind that can benefit the most number of people for a given effort, not just for a one off mission or for exploration, I'm talking about colonization. We need to capacity to send billions of people across interstellar distances.

GW Johnson · 2016-08-30 18:35:42

Would it not make more sense to send a probe to pin some of the planetary environment issues down, before expending much effort planning how to send people there?

Cart-before-horse problem, as I see it. All we really know about Proxima Centauri b is mass (poorly) and orbital period (fairly accurately). All else is nothing but egregiously-speculative bullshit.

GW

SpaceNut · 2016-08-30 19:17:48

The fastest probe to exit the inner planets to Pluto was the new Horizon on board the Atlas V family...
https://en.wikipedia.org/wiki/New_Horizons

On January 19, 2006, New Horizons was launched from Cape Canaveral Air Force Station directly into an Earth-and-solar escape trajectory with a speed of about 16.26 kilometers per second (58,536 km/h; 36,373 mph). On July 14, 2015, at 11:49 UTC, it flew 12,500 km (7,800 mi) above the surface of Pluto

So 9 yrs plus now if we place this same probe on the SLS what would we be able to achieve?

I would think that the antenna would need to be larger, a larger RTG and bigger power amps for transmission of data would as well be needed I would think.

Tom Kalbfus · 2016-08-31 07:13:12

There is another article on the Em-Drive, if this works out, we might not need linear accelerators or light sails.
https://www.yahoo.com/news/paper-nasa-g … 02200.html.
It is surprising that this has lasted longer than cold fusion, but if this is a hoax perpetrated by the media to sell copy, what about global warming?

SpaceNut wrote:

The fastest probe to exit the inner planets to Pluto was the new Horizon on board the Atlas V family...
https://en.wikipedia.org/wiki/New_Horizons
On January 19, 2006, New Horizons was launched from Cape Canaveral Air Force Station directly into an Earth-and-solar escape trajectory with a speed of about 16.26 kilometers per second (58,536 km/h; 36,373 mph). On July 14, 2015, at 11:49 UTC, it flew 12,500 km (7,800 mi) above the surface of Pluto
So 9 yrs plus now if we place this same probe on the SLS what would we be able to achieve?
I would think that the antenna would need to be larger, a larger RTG and bigger power amps for transmission of data would as well be needed I would think.

Another thing we would need would be artificial intelligence. Any probe that we send today would not be good for returning data, it might be good enough as a seeder ship however. Lets go down the list of technologies required.

1) A ship capable of reaching 1% of the speed of light

We can relax that somewhat a build a ship capable of reaching 0.1% of the speed of light, it would take 4,240 years to arrive at Proxima Centauri, and we would use an Orion nuclear pulse starship.

2) We would need artificial intelligence, something Marvin Minski is projecting to occur in the next 20 years

3) We would need frozen embryos, something we have already in use

4) And we would need to prefect artificial womb technology, the womb is an organ, once we've perfected the science of stem cell technology, we can grow human organs including wombs, we need an artificial brain that can interact with these organs (AI technology) and we'd then be all set to launch our first expedition to Alpha Centauri. Later technology might catch up with it or it might not! This mission architecture is a kind of insurance policy for the human race, the technologies employed to put it together might also be misused to destroy the human race, particularly atomic bombs, and artificial intelligence!

GW Johnson · 2016-08-31 10:24:36

A suggested course of action: try out the "starshot" laser sail technology while developing a very directional maser to beam the data home, and creating the receiver network necessary to receive that data. We'll also need miniature observation instruments to detect and measure any planets in the system. I rather doubt this will be a micro-craft, but it is a concept we could develop and build over the next few-to-several decades. So we'll need giant laser cannons, too.

Once these five developments come together, then send a probe through the Proxima Centauri system and get the data return on it. If (and only if) there appears to be a habitable planet there, then consider sending a colonist ship. To do otherwise is unethical in the extreme.

Under the assumption that the only propulsion technologies available to us at that time (many decades hence) are the ones we know work right now, then some sort of nuclear pulse propulsion generation ship is likely the way to send them. An alternative would be some sort of pulse propulsion "sleeper" ship, if some sort of cryo-suspension or artificial womb technologies become available before the ship's design "freezes". We have nothing like this today, with the exception of frozen embryos.

This will require robot electronics for sure. However, I don't see "artificial intelligence" in the sense that Tom envisions without a major change in technology away from the silicon chips and Von Neumann data architectures we use now. Stuff based on that will always only do only what humans can program it to do. It will never think for itself the way robots in science fiction can.

That's not to say such thinking machines cannot be created. It is to say they will not "grow" or "evolve" from the technologies and tinkertoys we are using now. How soon such things can be created is a very open question. My hunch is not for many decades yet, not until we can understand and manipulate biological neural stuff effectively. But that's only a hunch. Point is, no one knows how to do this yet.

But then, we won't be sending the ship for several-to-many decades at the earliest. Who knows? By then we may have created a means to travel faster than light. And thinking machines.

GW

Last edited by GW Johnson (2016-08-31 10:25:40)

Tom Kalbfus · 2016-08-31 12:43:40

A nuclear pulse starship can still b used to colonize Mars, before we develop Artificial Intelligence and womb technology. the problem is even with womb technology, a seeder ship is a no go unless we have the AI to be the parents of the human children we want to grow upon reaching the destination. I have every reason to believe, that parenting requires the full capability of human intelligence, nothing less will ever do, as human babies are quite helpless upon birth, not set of preprogrammed instructions can work to parent a child. But we should develop the nuclear pulse technology as soon as possible and colonize Mars, Calisto, Venus, Mercury, the Asteroids and Titan with those. We also need to hold at bay those who want to live within Earth's ecological limits within perfect balance with nature while we wait to destroy ourselves with the latest wave of programmable religio-robots, (ie religiously brain-washed humans) Iran and other nations in the Middle East are hard t wrk to develop those, they have been successfully field-tested in the battlefields of the Iran-Iraq war and are now being deployed to use against the West. I think its perfectly feasible that a religion could develop who's ideology is the complete extermination of mankind! I've seen enough fanatics willing to do away with themselves in order to kill other people, that religious meme is certainly possible, which is why we need to act as soon as possible.

JoshNH4H · 2016-09-02 09:15:22

Cherry picking a few choice lines to reply to:

Tom Kalbfus wrote:

We could always use antimatter

dictionary.com wrote:

Always (adv.)-every time; on every occasion; without exception

Right now we can create antimatter with an efficiency around 0.05%, capture it with an efficiency of maybe 1%, and store it with a loss rate of about 99% per second. If you want to produce antimatter for use 1 day later, you can do so with an efficiency of about 0% (rounded to the nearest 10^(-100,000)). Nobody has ever created an antimatter-fueled engine. We literally don't even know what principles such an engine would operate on. Would you try to extract momentum from the charged particles exiting the reaction in the 10^-25 seconds that they exist? Would you try to absorb or reflect the gamma rays, even though we know of no way to do such a thing without copious amounts of lead?

Your 30 AU linac goes well beyond a megastructure. 30 AU is 5e12 m, so it's more like a terastructure. As crazy as such a thing is (and mind you, it absolutely is crazy) we at least know in basic principle how it could work. Antimatter engines are crazier still.

Tom Kalbfus wrote:

It is surprising that this [conservation of momentum violating EmDrive] has lasted longer than cold fusion, but if this is a hoax perpetrated by the media to sell copy, what about global warming?

I don't have any real response to this because it's a silly conspiracy theory but I'm quoting it because it's also a funny (I chuckled when I read it) conspiracy theory.

Tom Kalbfus wrote:

2) We would need artificial intelligence, something Marvin Minski is projecting to occur in the next 20 years

The error bars on that estimate in effect make it worthless. Artificial intelligence was/will be invented sometime between 1900 CE and 1,000,000 CE, probably.

It seems like you're writing science fiction more than proposing realistic plans.

Tom Kalbfus · 2016-09-02 12:44:34

Past 20 years the future is simply the future, I won't be part of it most likely, I am nearing 50 now.

Antius · 2016-09-02 16:03:14

If human beings succeed in the development of controlled nuclear fusion in the next 100 years, we will be capable of living independently from the light of any star. That is a game changer that takes a little bit of thinking to get our heads around. We are accustomed to the idea of living on a planet and getting our energy from the sun. We tend to incorporate this assumption into our scenarios for the future of human habitation because it is so deeply ingrained into our psyche by our entire living experience. It is difficult to imagine a situation in which we would not live in this way, because it is the only way we have ever lived.

But the truth is that with controlled nuclear fusion at hand we would no longer need planets in habitable zones around stars, instead our focus shifts to those bodies with abundant materials that we need. Kuiper belt objects and comets are perfectly useful from that point of view and will ultimately be more useful to humanity than big planets with dense gravity wells. From the point of view of a fusion powered civilisation, traveling 4.25 light-years and sinking ourselves into a deep planetary gravity well would appear to make no sense as such a civilisation has developed an energy source that allows it to live anywhere. By the time we develop the ability to reach this world, it will be irrelevant to us as a destination. We will be more interested in the comet clouds and rogue dwarf planets that drift through the voids.

Last edited by Antius (2016-09-02 16:34:00)

New Mars Forums

Announcement

#26 2016-08-26 11:49:21

Re: Earth Like planet around Proxima Centauri?

#27 2016-08-26 14:39:29

Re: Earth Like planet around Proxima Centauri?

#28 2016-08-26 20:13:49

Re: Earth Like planet around Proxima Centauri?

#29 2016-08-27 00:34:10

Re: Earth Like planet around Proxima Centauri?

#30 2016-08-27 01:09:38

Re: Earth Like planet around Proxima Centauri?

#31 2016-08-27 04:21:22

Re: Earth Like planet around Proxima Centauri?

#32 2016-08-27 09:23:05

Re: Earth Like planet around Proxima Centauri?

#33 2016-08-27 16:54:46

Re: Earth Like planet around Proxima Centauri?

#34 2016-08-28 18:36:42

Re: Earth Like planet around Proxima Centauri?

#35 2016-08-28 19:09:37

Re: Earth Like planet around Proxima Centauri?

#36 2016-08-28 22:08:09

Re: Earth Like planet around Proxima Centauri?

#37 2016-08-28 23:23:19

Re: Earth Like planet around Proxima Centauri?

#38 2016-08-29 10:10:31

Re: Earth Like planet around Proxima Centauri?

#39 2016-08-29 19:01:15

Re: Earth Like planet around Proxima Centauri?

#40 2016-08-30 08:13:18

Re: Earth Like planet around Proxima Centauri?

#41 2016-08-30 08:54:11

Re: Earth Like planet around Proxima Centauri?

#42 2016-08-30 16:35:42

Re: Earth Like planet around Proxima Centauri?

#43 2016-08-30 18:35:42

Re: Earth Like planet around Proxima Centauri?

#44 2016-08-30 19:17:48

Re: Earth Like planet around Proxima Centauri?

#45 2016-08-31 07:13:12

Re: Earth Like planet around Proxima Centauri?

#46 2016-08-31 10:24:36

Re: Earth Like planet around Proxima Centauri?

#47 2016-08-31 12:43:40

Re: Earth Like planet around Proxima Centauri?

#48 2016-09-02 09:15:22

Re: Earth Like planet around Proxima Centauri?

#49 2016-09-02 12:44:34

Re: Earth Like planet around Proxima Centauri?

#50 2016-09-02 16:03:14

Re: Earth Like planet around Proxima Centauri?

Board footer