crubs

Well, the human body already produces alcohol dehydrogenase and is capable of carrying out the enzymatic processes you listed. http://makehumans.com/htmx/alcohol_dehydrogenase.php According to the link above, there are multiple alcohol dehydrogenases coded by seven genes in the body, and there is at least one form lining the stomach. One idea may be to somehow force the lining of the stomach to overproduce alcohol dehydrogenase and other relevent enzymes. The problem I see is that alcoholics will probably just end up chugging until they overpower the enzyme and get drunk anyways, similar to how many alcohols overcome the effects of emetic treatments. Nonetheless, it would be interesting to see the effects of a study on such a treatment in animals.

How did their attempted water landing go?

I was actually thinking about this. Specifically in the context of missions to Jupiter or Saturn that would take several years to complete a round trip. First of all, I don't think zero-g is a healthy option for that long a time no matter what. Centrifuged living quarters seem necessary. Otherwise, I think that an ability to remotely download video-games and movies would be a way to pass time. I think that astronauts would need to be "plugged in" just for psychological stability. Being on a ship for six or more years can make it feel like you're in prison.

Viruses and ribozymes aren't considered lifeforms at all. The term "simple lifeform" is an oxymoron, because all life as we understand it is erratically complex. I consider viruses and self-replicating ribozymes (if such a thing can or ever has existed) to be non-living organisms. A self-replicating ribozyme is currently the simplest non-living organism that natural models allow for, and yet we don't even know what this would look like if it can exist, or if it has existed. And as unstable as ribozymes are, I doubt they are capable of panspermia. From what I can see, undirected panspermia requires high a degree of complexity so that an organism has the machinery necessary to deal with the harshness of space.

All sounds theoretically possible to me, and very interesting also! I'd be curious to hear more about this story. The only problem I have is you describe your Saturn-like ice giant to have an "odd" orbit. What exactly does "odd" mean? Highly eccentric? Highly inclined? both? You could make it a captured planet with both, and have it's inclination close to 90 degrees. That would make it extremely difficult to explore.

I am absolutely right in regards to the fact that a cosmic Adam and Eve scenario is a feasible one. Your not wrong in the fact that this would eliminate genetic diversity. Genetic diversity is definitely a thing you want, but it isn't absolutely necessary. Eventually mutations would arise and our population would develop its own form of genetic diversity. That's how evolution works. Thanks for your post sky_walker.

And why do I need one exactly? This is a rather simple mathematical concept. We can practically prove it right here with a thought experiment: For our model, we can simply reduce the genes in our population to one. Mate 1: Aa Mate 2: AA The lower case letter represent a recessive allele that proves lethal before birth. Mate one has a 50/50 chance of passing either allele, meaning have the children produced by this couple will by this couple will be (on average), half AA and half Aa. Assuming random mating, heterozygotes have a 50% chance of mating with another heterozygote for the allele. If we look at out punnet squares we see there is a 1/4 chance of having a homozygous recessive child. Since in our model aa children result in miscarriage, we’ll assume the couple will simply have another child to replace them until their family is of average size. If generation two is Aa+Aa, then generation three will be 1/3 AA and 2/3 Aa. Assuming they have 6 kids, 2 of them will be AA and 4 of them will be Aa. If we count the alleles individually, we have 8 copies of the ‘A’ allele, and 4 copies of the ‘a’ allele overall. The ‘a’ allele in this generation has decreased in frequency by 1/6 from their parental generation of Aa+Aa, where the alleles were of equal frequency. Long-story-short, what we have done here is increased the statistical certainty of producing homozygous individuals, in doing so, we expose the hidden recessive allele to the eyes of natural selection which allows for a rapid weeding of this harmful allele. Of course, if we are to choose two individuals we could simply ensure that the couple is simply homozygous-dominant for both traits (AA+AA). In humans, we simply expand this logic to many more genes and, in theory, we could eliminate the existence of all harmful alleles in a single generation. Inbreeding could occur constantly and no negative effects are likely to occur for many generations. We actually observe this in some domestic breeds which are heavily inbred, that I can link: http://en.wikipedia.org/wiki/True_breeding_organism “A pure-bred variety of cat, such as Siamese, only produces kittens with Siamese characteristics because their ancestors were inbred until they were homozygous for all of the genes that produce the physical characteristics and temperament associated with the Siamese breed.†This means that true-breeding Siamese cats can be inbred repetitively and experience no significant health problems. Feel free to check my math, while it was never my strong point, I did well on my evolutionary biology’s population genetics exam. Much of this I can’t cite because I learned it at my university as opposed to studying it online. Look up “Allele A1†if you want a simplified computer model of population genetics. Otherwise, I’m happy to demonstrate the concept further with other mathmatic models. I can show how a allele doesn’t have to be lethal for the same concept to apply, and also how hidden beneficial alleles are capable of rapidly rising to fixation by the help of inbreeding. But it’s all based on the same logic.

Nope, I'm right. Again, those two people must be carefully selected. If you can ensure that they aren't heterozygous for 'harmful' alleles, there isn't a problem. In fact, it could actually prove beneficial since beneficial alleles will fixate at an accelerated rate. All this is mathematically demonstrable.

Given that the individuals are carefully selected, you would only need two, though it's less than ideal. A little bit of inbreeding actually isn't a bad thing in terms of population genetics. Those who've studied population genetics know that inbreeding actually accelerates the evolution of a species. It weeds out harmful alleles and encourages fixation of hidden beneficial alleles. This may eliminate genetic diversity, but eventually the population would evolve it's own unique racial characteristics.

Place humans on other continents and do they cultures develop to look the same? No. There are cultural analogs, but oftentimes divergence occurs and creates an entirely new culture. I would consider that photograph practically impossible for another world.

The asteroid could have oxygen produced by radiolysis of ice water. That mixed with methane would ignite with merely a spark.

This is a very political topic, but since it's happening. I like Rick Perry's opt-out instead of opt-in. The choice is exactly the same and the only difference between the two is that opt-out systems have more participation. The only arguments I've really heard against it is people not wanting to do it. If you don't want to, then don't, you still have that option. I don't think we need to force people to have vaccines, especially since some people may have religious objections. As an American, religious freedom is one of my most prized freedoms.

Yeah... That ain't happening. I find it difficult to suspend my disbelief in such a scenario. I find it really hard to believe that earth would ever need methane so bad that it would mine it from asteroids. I mean, We could extract methane nearly-for-free from all the mounds of cow poop that factory farms put out. However, there are serious considerations for mining asteroids for metals. They say asteroid mining could reduce the costs of some metals to practically nothing. Methane can also be refined into hydrogen by pyrolysis: http://en.wikipedia.org/wiki/Sabatier_reaction#International_Space_Station_life_support Hydrogen, in turn can be directly used to fuel nuclear thermal rockets without needing oxidizer: http://en.wikipedia.org/wiki/Nuclear_thermal_rocket You could have the mine operate as a metal-fuel mine simultaneously. It's a tricky balance between being scientifically accurate and trying to avoid bogging down the reader with hard science and excessive detail. EDIT: Hydrogen is actually more explosive than methane, and careless pyrolysis is a fine recipe for disaster.

The question I'd have about methane is, what exactly is your company using it for?

I was also wondering. If the parent body was orbiting in the habitable zone, it could in theory hold multiple habitable moons. Can you imagine the implications for the development of space travel of a civilization that lived in a solar system with multiple habitable worlds?

http://en.wikipedia.org/wiki/Terraformation_of_Mars "Raising temperature of the poles by four kelvin would be necessary in order to trigger a runaway greenhouse effect." "Impacting an asteroid, which is often considered a synergistic effect, would require approximately four 10-billion-tonne ammonia-rich asteroids to trigger the runaway greenhouse effect, totaling an eight degree increase in temperature." 10 billion tonnes doesn't seem that bad... Nuclear pulse with hydrogen bombs. Only problem is that the ice would be partially vaporized by the blast(s).

I think the best mechanism for terraforming would be to redirect comets and icy asteroids to impact mars. We would need something with a lot of delta-V and, preferably, a lot of thrust. With modern technology, the only thing that could pull that off with reasonable timing and cost would be a nuclear pulse rocket. I'm not sure how long it would take since I'm not sure how much atmosphere Mars needs just to reach the Armstrong limit, nor do I know what icy bodies are capable of delivering the necessary mass. My intuitive guess says that it would take around a century. Though really, I have no idea.

To an extent, I agree, some things are greatly oversimplified. On the other hand I feel that my case is the opposite. For example my dad (also an astronomy nerd) wondered why we never put a lander on Mercury, and why we only got an orbiter there recently. After all, it's a lot closer than Jupiter or Saturn. I may have wondered the same thing until I discovered the pains of doing so with Moho. I used to think that you just point in the direction of the planet and fire. Now I know that this method is horribly inefficient and this has allowed me to sympathize with the struggles that NASA goes through. But still, KSP helped me realize that a lot is possible when resources are available. I now grasp how much technology NASA has available but can't put to use because the money isn't there. I would also disagree with your statistic, but I wouldn't know. It would be interesting to see a formal study on KSP players to see what they've learned and if they've gained any misconceptions about real-world spaceflight. And for that matter, how it's influenced their interests in such.

The reason I say this is because I've seen how children can easily be excited by basic facts of astronomy. In high school, I voluntarily taught 4th-5th graders about astronomy and these kids were hooked. But I can only stimulate interest in a classroom full of kids per week. A game like KSP on the other hand can possibly stimulate a whole generation of excitement for space-travel (if it gets popular enough). I've had a decade long interest in astronomy, but only recently have I been interested in space exploration, that I owe to KSP. With that excitement comes frustration as to how NASA has done nothing outside of LEO due to a lack of funding for 40 years now. Politics has failed us for 40 years and I imagine it will continue to. I think that what we need is a grassroots movement to get our space-program going. Politicians have too many issues to deal with as it is. Things like jobs, the economy, healthcare, social security, and other things are far easier to market then playing golf on the moon. I don't think excessive scientific accuracy is necessary. All scientific models are inaccurate to some degree, otherwise they wouldn't be models. Models are designed to help us better understand a complex world. Right now I'd say KSP is a pretty popular cult-community. Though I'm guessing we're vastly outnumbered by bronies, but that can change.

Do you think KSP is stimulating significant interest in topics surrounding space exploration and rocket engineering? In our personal lives, I'm sure the answer for many of us is a blatant "Yes", but do you think it's slowly acting as a game-changer in the grand scheme of human space travel? Do you think it will in the future?

Actually I was reading a proposal to place an aircraft on Titan with an oxygen as opposed to a fuel tank. The engines would be designed to breathe methane to provide propulsion.

I request you make one planet a brown dwarf on a highly eccentric orbit, with moons the size of Kerbin.

They should make kethane mining and ore mining gear super expensive. But otherwise, I say it's fair game since it's based on an actual concept.

Here's my take on the United States of Kerbin