Future of Ceres

[mithridates]

Just curious what is going to happen to Ceres as the sun begins to heat up over the next few billion years (assuming we don't get to it and build settlements). I see the maximum temperature measured there so far has been only -38C, and given the vast amounts of water (probably) below the surface, what would happen to it were it to heat up?<br /><br />Oh, and while we're at it I noticed a thread from about a year back about terraforming Ceres on another board. One poster mentioned that to get the required bar of pressure on Ceres one would require some 200 km of atmosphere, which would trail behind the 'planet' and make it into something like a comet. I believe he was assuming that we are going with a breathable atmosphere identical to that of the Earth, and in addition to that a full bar wouldn't be necessary either - a bit over half a bar should do fine. What is the heaviest potential atmosphere that could be created that would still support animal and plant life? If there is enough O2 and CO2 and anything else necessary, it shouldn't matter if the rest of the atmosphere is made up of another gas besides nitrogen. Or am I way off base here, as is often the case? <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[bonzelite]

you raise very good issues.<br /><br />in my opinion, we really are not certain about what a minimum or maximum is. what is required to suppport life? what kind of life do you mean? earth life? as well, earthen life has lived in outer space without any atmosphere for a considerable period of time. terraforming assumes earth-like conditions. <br /><br />insofar as the first question, that is a good one. i often think about this, too, in terms of all of the icy moons and gas giants farther out. will these planets become warm, tropical, wet, nice places? will titan melt, chemically change, and become earth-like? over time as the sun "swells" (which will probably not be instantaneous, but require millions of years) will earth life migrate to the warming outer planets eventually? <br /><br />what would happen to Saturn if it were to heat up? would it remain a gas giant? or would it burn away and reveal a rocky terrestrial world? <br /><br />this is hard to answer. there are "hot Jupiters," as we know them to be, orbitng nearly touching their sun. and they are not "burned away." but what about icy worlds like Europa? will that become a liquid ocean planet? like earth? <br /><br />are these worlds already within our own solar system sort of "waiting in the wings" to become the next Earth, awaiting the solar conditions to change?

 

[mithridates]

Apparently it has enough gravity to hold onto an atmosphere for hundreds of years, making terraforming not that odd a concept. Over the long term it would lose it again but with a few centuries of leeway any civilization capable of terraforming would certainly be able to maintain an atmosphere. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[mithridates]

While we're at it, why would anyone bother going into space? Waste of resources there for the time being too. I think that's a bit of a disingenuous question.<br /><br />What I'm curious about though is the rate of loss for some heavier gases compared to those on the Earth. We're assuming that money is no object here. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[mithridates]

Yes, and...? The whole premise of the thread is 'what if'. The question asked in the op is in reference to types of gases that could be used, not a request for peer review on a project to terraform Ceres that needs to be sold to the public. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[nexium]

Assuming the 200 kilometers for one bar is correct, we can have a one bar of atmosphere 200 kilometers below the surface of Ceres, with only three millibars of atmosphere on the surface. Three millibar may be enough for photo synthesis if it is 1/3 carbon dioxide, 1/3 oxygen, and one third water vapor.<br />Giant orbiting mirors are likely needed even with green houses, to keep the plants warm enough. The humans could live far below the surface. Neil

 

[mikeemmert]

Tunneling into Ceres would produce a great deal of material that must be removed from the tunnels and rooms. If this were made into space colonies, the surface area would rapidly exceed Cere's surface area.<br /><br />There are easier asteroids to mine. I would think of Ceres as being a "Historical Preservation Site", protected by gray-haired little old ladies with politcal connections you wouldn't even dream of. A little milk and cookies for the Congressman's grandson goes a long way.

 

[mithridates]

BTW, with the new revelations found in this article:<br />http://space.com/scienceastronomy/070125_mars_atmosphere.html<br />Does this mean that we've been overestimating atmospheric loss from solar wind for other bodies as well? The "Ceres' atmosphere, if it had one, would be knocked away in a number of centuries" was a quote from someone on this site but I've yet to see anything on the issue in an actual paper. If Mars is only losing 20 g per second into space, can we extrapolate the rate of loss for other bodies based on that? <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[mithridates]

That's a terrible example. See nexium's post above for a polite, constructive answer. Your blowhard response doesn't disguise the fact that you don't know enough about the subject to contribute as do the other posters. I notice you have no idea whether the less-than-expected atmospheric loss on Mars means we have overestimated that of other bodies as well. If you think that question is comparable to using wings to flap to the Moon, well then, continue doing so I suppose. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[mithridates]

You didn't happen to see the thread on terraforming the Moon, did you? A poster there suggested an artificial heavy gas, SF6 if I remember correctly. I believe that was based on the idea of bringing in extra mass (SF6 has a density some four times that of CO2) in a smaller area, and then filling the rest in with gases for photosynthesis and human respiration. I'm not sure what ratio would be needed of each though, or if it's even possible. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[mithridates]

It's possible that I didn't make the original question clear enough. What I was looking for more in the 2nd question than anything was (besides the question of Ceres) what sort of gases can make up a breathable atmosphere, such as how great ratio of a heavier gas such as SF6 can be snuck into an atmosphere while still leaving it breathable to humans. Or in short, how can an atmosphere on a smaller body (anywhere) be made without having to extend it up to a height such as 200 km? <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[dragon04]

I think Nitrogen is always going to be best because it's non-reactive in its pure form, IIRC.<br /><br />While it doesn't answer your question, enveloping an asteroid with an atmosphere isn't the answer. Enclosed habitat works much better and is far quicker and easier to do in terms of economy.<br /><br /><br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[silylene old]

CE, this is a silly and absurd question to debate. But, if you add enough gas, the gas from its own mass and gravity will allow additional gas to be held gravitationally bound better and better....until taken to absurdity, you arrive at a gas giant planet. The diameter increase will be significantly more than 200km when one arrives at this point. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[MeteorWayne]

Or in this case, not an asteroid, but a "Dwarf Planet" <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[mithridates]

Actually, out of the box thoughts such as an impermeable membrane etc. are often exactly what I'm looking for in a thread like this. One other subject I've often thought about is the effect of the solar wind in a binary system with two objects of a similar size orbiting each other quite closely. What would happen for example in a system with an object such as Ceres with a moon with a mass about a tenth of Ceres at perhaps a radius of 10,000 km or so, much like Pluto or Charon. In a system such as that would it be worth it to try to combine the two? Also, if Ceres turns out to have moons once Dawn arrives, would it be possible to make use of them to try to alter Ceres' orbit to make it more accessible to us?<br /><br />(You don't have to answer these of course, it's 3 am over here and I'm just imagining) <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[antius]

What matters for human/plant metabolism is the partial pressure of oxygen/CO2 available. Humans have difficulty breathing at Everest height with a partial pressure of oxygen about one half sea level, or 100millibars. At much less than that pressure, oxygen cannot diffuse through the alveoli membranes in the lung quickly enough to fuel human metabolism. So, assuming you are happy with a pure O2 atmosphere, about 10% Earth sea level pressure can be considered minimal for human habitation.<br />

 

[antius]

Actually, there is a way in which small worlds could hold onto atmospheres for geologically significant timescales.<br /><br />If memory serves, the energy of individual gas particles follows the Boltzman distribution. If Ceres were to have an atmosphere, at any given time, a certain fraction of the molecules at the top of the atmosphere would exceed escape velocity. For Earth, this proportion is miniscule, on Ceres, it would be much higher. So the atmosphere would gradually leak into space and would be blown away by the solar wind. The Ceres atmosphere would therefore have a half-life, probably measures in certuries.<br /><br />The leak rate could be minimised or even eliminated by providing Ceres with a powerful magnetic field, using superconducting rings around the equator. As gas slowly leaked from the atmosphere, it would be ionised by solar ultraviolet radiation. The charged ions would tumble along the magnetic field lines and reenter the Ceres atmosphere at the polls. If the magnetic field were maintained indefinitely, then the atmosphere would be continuously recycled over very long timescales.<br /><br />The extent of the atmosphere would be vast. Ceres has a surface gravity only 2.5% that of Earth and only 0.6% Earth's surface area. So to provide 1 bar of pressure on the surface you would need an atmosphere with a mass equivelent to 20% of the Earth's, with a column density 40 times that of Earth's atmosphere. The mass of the atmosphere would exceed 1% of the mass of Ceres. The atmosphere would also have a very deep ionosphere, probably extending at least one Ceres diameter into space.<br /><br />At the end of all of this, you have a rather small, miserable little planet. The mass of the atmosphere would be such that the surface would probably retain heat far more effectively than the Earth, so even at Ceres distance from the sun, it may be possible to provide a relatively warm surface environment. The intensity of sunlight at Ceres distance from the

 

[antius]

One obvious problem with attempting to terraform Ceres or any other 'ice world' in this way, is that the average temperature of the planet, would always have to remain below zero centigrade, otherwise the whole thing would melt into a water world. This might prove to be a problem for any future colonists wishing to provide a comfortable environment on the surface.<br /><br />On the plus side, this only places a limit on the average temperature of the planet. It would be perfectly Ok to to maintain an average temperature of 30 degree C in the summer, so long as it was matched by an average temperature of -30 degrees C in the winter. It may even be possible for the colonists to simply move to different parts of the world, always enjoying the hot seasons in each location, while the other bits cool off.<br /><br />If ever the human race masters the secret of fusion, it may one day be possible to artifically illuminate worlds like Ganymede, Calisto, Triton, Pluto, Eris & Quaoar, providing them with earth-like, magnetically sealed atmospheres.

 

[mithridates]

I was wondering about that myself. I don't believe we yet know how thick the crust is above the ice layer, so that would be good to know.<br />http://en.wikipedia.org/wiki/Image:Ceres_Cutaway.jpg<br /><br />Maintaining a temperature below zero wouldn't be too much of a problem though - the coldest capital in the world (Ulan Bataar) has a yearly average temperature of -1.3. That includes extremes of both heat and cold though, so just keep things cool and away from extremes, and you have a somewhat chilly but still comfortable place. The coldest thing about the winter is the wind anyway.<br /><br />http://en.wikipedia.org/wiki/Image:ClimateUlaanbaatarMongolia.PNG<br /><br /> <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[antius]

One way of getting around this problem (especially if Ceres has a thick uniform crust) would be to install heat pumps on the surface, effectively removing heat from the crust, and using it to warm the biosphere. The amount of power needed would be collossal.<br /><br />For more distant worlds, such as Pluto, Sedna, etc, The surface would probably have to remain colder than zero most of the time. Plants, cities and food production would probably need to remain in domed enclosures just to keep sufficient heat in.

 

[mithridates]

This is quite interesting. What would the costs be then of terraforming for Mars vs. Ceres I wonder? Though Mars has an atmosphere already it's physiologically no different than not having one at all, and Ceres has a surface area of 3.1 million sq. km versus 145 million for Mars, a huge difference. I suspect the challenges of greater distance and lack of atmosphere would more than be made up by the much smaller size.<br /><br />Another site tells me that:<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>If the stats for the first 100 asteroids to be discovered are typical, 44% have orbital periods within 1O% of Ceres' so that one third of these or almost 15% of all asteroids would be within 60 degrees of Ceres at any given time and remain there for fifteen years or longer before drifting out of range. Some asteroids will 'fly in formation' with Ceres for centuries. Two target groups suggest themselves: the 'out-fronts' ahead of Ceres but in slower larger orbits, and the 'in-backs' behind Ceres but in faster smaller orbits. At any rate access to 15% of the Belt should do us well for quite a while. To compliment Ceres as regional centers, 210 km wide #88 Thisbe (takes 1415 yrs to drift 120 degrees with respect to Ceres) and 163 km wide #39 Laetitia (3540 yrs to drift 120 degrees) might serve.<p><hr /></p></p></blockquote><br /><br />I don't know how I'm going to be able to wait until the Dawn probe reaches Ceres. I don't suppose anybody knows what major observations of Ceres are planned before 2014? 97 days until launch. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[antius]

Mars would probably be cheaper per unit of surface area. But the downside is that it would take 100,000 years to convert the carbon dioxide atmosphere into a breathable oxygen atmosphere. With Ceres, the transition could be completed within a few decades. All that would be needed is a few million cubic miles of ice (in the form of a large comet) and a very powerful super-conducting magetic ring, wrapped around the equator. The sun will do the rest of the hard work for us.<br /><br />With 3.1million square km of surface area and an average population density of 300 people per square km, Ceres could support a population of 1 billion people. The world would also be an easy site for construction of a space elevator, given its low gravity. We can therefore imagine that Ceres would serve as a base for exploitation of other asteroids.

 

[mithridates]

Sounds good, I'm sold. Adding to that the escape velocity only being one tenth that of Mars, it seems that Ceres might be a preferred destination after all.<br />How much is saved for the return trip home by having such a low escape velocity compared to Mars?<br /><br />I just stumbled across a page devoted entirely to the dwarf planet:<br /><br />http://home.comcast.net/~eliws/ceres/ <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>