todofwar

But that's all within a few hundred years. Plastic only lasts for thousands, and much of it would ultimately end up underground and converted back to crude. No structure would survive that long either, on the timescale of hundreds of millions of years mountains get worn away. I suppose it kind of depends how long the civ lasts. Sure, we can use things like levels of lead to track industrial levels, but that's on the scale of five to ten thousand years. Have we really altered the chemical makeup of the earth so much that it would show up after the record gets compressed? What's our resolution on measuring things like CO2? I have a very hard time buying our ability to break down the record to the level of millenia by millenia.

This. Let's rephrase, we all die from a super virus. How long until evidence of our civilization is completely wiped? I've read plenty on evolution thank you. And no, the fossil record is not complete, far from it. Though it is complete enough for us to fill in many blanks. Think of it this way: we haven't catalogued every extant species, what makes you think we've catalogued the extinct ones? This kind of post drives me crazy. I spend all day talking serious science, this is where I come for interesting speculation. Yet some people get so up in arms about anything that's not a perfectly grounded scientific discussion.

So, without getting too ancient anliensy, what evidence could be expected if there was another civilization as advanced as ours sometime in Earth's history? Our window would exclude the early bombardment, obviously, but conceivably the dinosaurs had enough time evolutionarily to spit out a species capable of building spacecraft, and I think that the fossil record has enough holes for one species to slip through. And of course homo sapiens have been around for a long time, most of that time we assume we were just cavemen. But what if there was a civ that rose and destroyed itself? I'd say the latter is less likely, we should see some kind of evidence for it. But the former? The continents don't even look the same as they did during the triassic, surely that's enough time for most evidence of civilization to be erased. If they had launched sattelites, would we have found them or could there be some small ones hanging out? If it's impossible for us to miss one, how long until all our satellites' orbits decay and they fall back to Earth?

Venus has five times more nitrogen than Earth actually, it just has that much CO2 in it's atmosphere so the nitrogen makes up about 3%. Nitrogen and oxygen don't have escape velocity, and don't become split by UV. Hell, oxygen gets heavier, becomes ozone. N2 is very stable, in fact chemists use it as an inert atmosphere to study highly reactive compounds. They will still deposit somewhere, life deposition finds a way

http://www.slate.com/blogs/bad_astronomy/2016/06/13/japanese_space_probe_akatsuki_is_now_sending_back_images_and_data_from_venus.html Very nice shot of Venus in the IR, and an animation showing cloud motion over time. The equator seems quite stormy.

Gonna jump in here because I'm so tired of hearing this argument. NASA has tons of projects going on at multiple research stations across the country. Thousands of scientists at JPL, Goddard, Ames, and others are working on solving real scientific problems. There seems to be this prevailing myth that NASA needs to be single mindedly focused on something, but in reality it's a very large funding agency devoted to all kinds of projects. Occasionally they have bigger plans that take a few mroe resources, but it's like saying the national science foundation has no focus because they're not building the US's version of the LHC. Or the national institutes of health have no focus because they're not doing the human genome project. Lack of a big all consuming project means NASA can try and tackle more at once. SpaceX is doing so much better because they don't have to worry about having parts built in fifty congressional districts or appealing to people who think we should have kept going to the moon, but in terms of scientific discovery it's not even close. Yes landing a man on Mars would be badass, but as was extensively argued in another thread you can get 100 missions to mars for the cost of one human mission. Sorry if this has already been said, I'll get around to finishing the thread soon.

Now I'm curious, as someone who is four years into their first PhD, what compelled you to go back for number 2?

Was watching X men First Class again today and it had one thing that I've seen a few times. At one point they ask Beast if he can fly the jet, and he says he designed it. Pretty sure no one designs a whole jet by themselves, but whatever let's let that slide. As far as I know aerospace engineering and piloting are two separate skillsets, I doubt the team that designed the Blackbird could actually fly the thing, that's why you have pilots. This gets to the annoying tendency to lump all scientists together into one super scientist who can do engineering, biochemistry, knows allot about physics, and can of course hack any computer system. In real life you specialize. And whenever anyone says they have "multiple PhD's" I want to punch someone, if you get more than one PhD you probably need to move on with your life, unless your so engrossed by science you can stand being at or just above the poverty line for five years per PhD.

I think this nicely summarizes what I was going for, but I like the idea of leveling up different parts classes by using said parts in missions, not just getting them through unrelated science experiments

So, I have yet another career overhaul suggestion that tries to add a touch more realism. It's always bothered me that you get science by putting mystery goo on Mun and that somehow let's you build a better rocket, as I'm sure most people agree. My thinking is to tie research to how many flights you've had certain parts which would unlock further improvements. So you start with very basic 1.25 m tech, and each time you launch more 1.25 m flights with the latest equipment it gives you more science towards the next level. But to get better 2.5 m tech you have to use more 2.5 m parts. And to get more solar panels you need to deploy more solar panels, etc. Going to different planets and moons would give a boost, but maybe not biomes. And each part progression is independent, but can be simultaneous. However, you have to cough up some money to actually purchase the next upgrade once you have the science for it. This has probably been suggested before, but I want to add one more component: money. Basically, you will have a budget that you can assign to rockets or to improvements or to science, so that you can get quicker science progression at the cost of not investing in other improvements. And your budget goes up with reputation, but you can supplement it with private sector contracts. The science experiments would contribute to rep allot, which means biomes remain an important part. Also, your rep would fall pretty quickly if you don't launch anything or only launch to Mun a million times (repeated launches to the same body would give a penalty to any rep you gain, that goes away as you launch less to it). So if you try and cheat by just time warping until you get money you'll see your overall budget grow slower and slower until it's 0.

http://www.bbc.com/news/science-environment-36197603

They would not really have a choice would they? You'd need enough people active not just to maintain the ship but to create enough of a social group to sustain themselves psychologically, so it would function much like a small tribe does, keeping themselves going for eons until the destination is reached. They would have to understand that they can't make a return journey, so it might not be as much of a burden as you think. In fact, there might be more strife over actually beginning the breaking and landing maneuvers, since that would represent a change and society always resists change. This hypothetical space bound group might decide better the devil you know, not worth risking everything on landing on a planet. Sure, all kinds of rational arguments for why they should land, but if you and the last four generations all lived on this ship it might seem like the safer place to be.

I feel like Moore's Law won't actually hold out that far. We're going to hit a physical limitation on what kinds of computers we can build and an economic limit on what the market demands. At a certain point it becomes kind of like manned space exploration, just doing it for the sake of doing it more than any benefit over unmanned. So more powerful computers will only be built to say you can build them, while the real advances will be in better algorithms to take advantage of what we already have. Back to the topic of this thread, I think it would be a set of maybe twenty humans that replenish through a sperm bank (EDIT: you would want ~ 10,000 samples or more, and since sperm is easier to harvest than eggs it makes sense to not worry too much about mitochondrial diversity and focus on genetic diversity. Men that are born could add to the stock so that it can replenish as well over time, you just want to make sure it gets sent to the back of the line), the intervening generations of which will be born and grow old and die (probably through a planned suicide at 65) on the ship. It will need to be designed to have every part replaced on a five year timeline, no new materials just take the part and melt it down and reforge it. And most of the mass of the ship would probably be materials to create a supply chain once you reach the destination, extractors and refiners etc. No need for full embryos, just lots and lots of sperm.

I see, I was misunderstanding what longitude they were talking about. Many thanks!

That doesn't really answer the question. I know what the term means, I was wondering if it was constant and if so why. Earth's rotation isn't special, if you launched from the moon and entered Earth orbit why should your ascending node rotate perfectly with the Earth?

This is kind of hard to explain as a question but it's been bugging me ever since I started playing KSP (this is about real life though, not what the game does). Does the longitude of the ascending node move? What forces it to stay constant since Earth is rotating? Does it matter if you launched from Earth or inserted from somewhere else? If my LAN is 45 degrees W, for example, than will my satellite always cross the equator at 45 degrees W or will it slowly drift?

Or the even more succinct: you can't win, you can't break even, you can't get out of the game. I had an idea for placing your periapse just low enough to compress hydrogen in front of you without heating it too much (you will heat it because you're compressing it, obviously, but if you're shallow enough maybe not to plasma levels) so you can collect it into your tank. With some thermoelectrics you could even capture some of the heat of the compressed hydrogen and you have yourself fuel and energy for an ion drive. So, not just the heat but capturing the gas as well might work. Of course, that's not going to be the best way to get energy since thermoelectrics are only like 20% efficient on a good day.

I don't know, it has a certain "original star wars" charm to it

Exactly. And don't forget, they had a pretty limited window to get data from the lander, but even that will probably be extensively studied for a long time. Data analysis is the less glamorous, more grueling, more soul crushing part of science that never gets mentioned but is probably the most important step.

Every time I check my journal of the American chemical society rss there's about four or five CO2 reduction papers, ranging from electrochemical to photo activated. So, clearly someone expects this to be viable since plenty of money is getting dumped into it

The entire science system. The amount of lab work and simulations that NASA does probably trumps the amount of science gotten in space, and deciding which instruments to send requires tons of planning based on what you actually want to study and what instruments can be loaded onto a probe. And actually getting the data is step one out of ten. But overall KSP is probably as good as any other Sim out there. Anyone actually want to run a city? It's not as easy as simcity. Or managing an empire, or even the most "realistic" war games. But it is hopefully inspiring people to ask, why can't we do that mission in real life? Who will then go on to find out just how to do it. And if not, they hopefully learn about the importance of [redacted for getting too political]

I certainly hope not for the sake of my career past grad school

It's been a while since I've seen that, I could of sworn orion was the service module for the whole mission. Funny how memory plays tricks sometimes.

@fredinno It would be shorter than the Mars trip, but still longer than any other manned mission. I think going to a planet is easier than going to an asteroid just because we already did multiple planets and landed multiple rovers on Mars, but only got to orbit around a smaller body once and didn't manage to stick the landing (not hating on that mission, I thought it was great, just pointing out asteroids aren't necessarily the easy targets people so often think they are). Also, HAVOC involves getting onto a planet (can someone please come up with a name for "landing an airship from orbit"?) and getting back, a complication you can't test run with phobos. Not that you would, but yes an airship would work just fine on Mars since the atmosphere is all CO2. The fact that it's so near vacuum isn't so bad, I think weather balloons go to parts of our atmosphere that are thinner but I may be wrong. Still, not a great idea unless it solves the whole landing issue, since you can't use parachutes. Full disclosure, Mars gets so much attention that it seems easier to sell Venus missions as somehow helpful for Mars missions. Even if it's something of a stretch.

Imagine the forum war if NASA names an EML2 station Minmus. Those excited about the KSP nod against those nitpicking that Minmus isn't at KML2.