pluto is officially red

[Broomstick]

I know that we are looking and IIRC have found alien microbes and stuff. I was asking about things beyond that. As in, actual aliens. I don't think anyone is searching for those except the SETI telescopes supposedly listening in for their radio signals.

Actually... no, we haven't found alien microbes. We have found that some Earth microbes can survive a few years in space and vacuum, but no actual from-another-world life. I think tardigrades might also be able to withstand space conditions, albeit in a dormant form.

Nope, still looking for life out there, still haven't found any. Closest we've come are naturally formed amino acids, that's it.

[Purple]

As I said later, I was referring to life beyond just microbes, extremophiles and other microorganisms. You know, something we can talk to and stuff. As opposed to something you look at under a microscope.

Nothing like that yet. Microbes are likely to be found first.

I know. I was not asking if it was likely that we'd find any but if anyone was even considering actually looking for it.

[Broomstick]

That's the whole point of SETI - to look for life we can talk to. How long has that project been running?

[Ace Pace]

As I said later, I was referring to life beyond just microbes, extremophiles and other microorganisms. You know, something we can talk to and stuff. As opposed to something you look at under a microscope.

Nothing like that yet. Microbes are likely to be found first.

I know. I was not asking if it was likely that we'd find any but if anyone was even considering actually looking for it.

Please describe such a mission. It's the sort of problem we attempted to "attack" decades ago when the SETI project was started up and similar endeavours. But today, AFAIK, no one is seriously attempting to search for intelligient life because they're clearly not transmitting on anything we're aware of, so there's no point.

Science isn't a "let's think up something wacky and find ways to do it", you need a good angle to start your research from.

[SpottedKitty]

But today, AFAIK, no one is seriously attempting to search for intelligient life because they're clearly not transmitting on anything we're aware of, so there's no point.

Way, way too early to tell that for sure yet. You're thinking on the wrong timescale — we've only been halfway-seriously looking for, I think, not even 50 years. That isn't even long enough for a light-speed message to get there and back from anywhere interesting. There are some obvious radio frequencies to try, but what if Whoever Might Be Out There doesn't use radio, or doesn't use it the same way we do? Does whatever technology they do use exist in our box of tricks yet, or is it no more than a weird anomaly in one of our theoretical equations? For that matter, could we have already recieved messages, but we haven't recognised them for what they are? The most likely answer is "probably not". Is it the right answer? We don't know.

Yet.

Science isn't a "let's think up something wacky and find ways to do it",

It never has been — that's the tabloid journalists' idea of "what scientists do all day in their ivory towers".

[Ace Pace]

But today, AFAIK, no one is seriously attempting to search for intelligient life because they're clearly not transmitting on anything we're aware of, so there's no point.

Way, way too early to tell that for sure yet. You're thinking on the wrong timescale — we've only been halfway-seriously looking for, I think, not even 50 years. That isn't even long enough for a light-speed message to get there and back from anywhere interesting. There are some obvious radio frequencies to try, but what if Whoever Might Be Out There doesn't use radio, or doesn't use it the same way we do? Does whatever technology they do use exist in our box of tricks yet, or is it no more than a weird anomaly in one of our theoretical equations? For that matter, could we have already recieved messages, but we haven't recognised them for what they are? The most likely answer is "probably not". Is it the right answer? We don't know.

Yet.

Science isn't a "let's think up something wacky and find ways to do it",

It never has been — that's the tabloid journalists' idea of "what scientists do all day in their ivory towers".

You're pretty much proving my point for me. We're not seriously searching for aliens because we don't have any lead for precisely how to do it.

[Simon_Jester]

I attended a seminar earlier today given by a senior scientist in the New Horizons project. Who incidentally has grown old and conspicuously gray waiting for the proposals to be accepted, the instruments built, and the probe launched... and now his project is almost done, the probe is a week out from Pluto!

[On the downside, downloading the data from the flyby will take like fifteen months. Turns out the best you can do with a thirty-watt transmitter from the neighborhood of Pluto is a download rate of about 300 baud...]

I'll throw out some highlights from what I heard there, the parts that might interest people, later.

Those are all good answers that make sense. I can't complain. But I do have one thing to genuinely ask. Do we actually, genuinely and sincerely actually look for actual alien life? I always thought that was a gimmick to sell people on handing more money to space research.

Short answer:

Yes.

Longer answer, which will only make sense if you engage the parts of your brain that hopefully matured after you turned twelve...

Almost every science probe mission we send to Mars, to asteroids, to comets, to the Jovian planets, or even to the moon, gives us information we CAN use to better understand what alien life might look like, where we might look for it, and so on.

If there is life in our solar system anywhere other than on Earth, it will be hard to find- tiny, durable microbes, or organisms swimming around in an ocean buried under ten kilometers of ice, or some such. It's not going to involve Marvin the Martian walking in front of our camera and waving 'hello!'

Before we could locate such things, we need to have a lot of information about the basic nature of the worlds we're exploring. We need good models of the physical structure and composition of these worlds. We need to understand what kind of energetic processes are going on on (and inside) these worlds, that might fuel the chemical reactions that drive life. We need to know where to look, and where not to look.

Therefore, every probe we send teaches us things which are important in order to refine and advance the search for life.

That does NOT mean the people who build the probes expect Marvin the Martian to walk in front of the camera and wave 'hello,' because that is not going to happen. It does NOT mean spending millions (or even thousands) on some kind of 'life form detector,' because there's no such thing as a life form detector.

If you are as intellectually mature as you need to be to participate in this conversation, I hope you find that to be an informative answer.

I guess I should have been specific. I know that we are looking and IIRC have found alien microbes and stuff. I was asking about things beyond that. As in, actual aliens. I don't think anyone is searching for those except the SETI telescopes supposedly listening in for their radio signals.

That's because there are no such aliens to be found in any conveniently accessible place in our solar system, and we lack the means to go exploring other star systems.

I'm not sure what you think is going on here. Do you think there are people walking around on Mars and we just have to... find them, somehow, and we will have "discovered aliens?"

Because as I mentioned, that's not how it works. If there are aliens to be found, they are in other star systems, or they are buried under miles of ice, or they are microbes. Or possibly two or more of those three things at the same time.

Before we can even begin to look for such creatures in any way besides listening to the sky in the hope that they send radio signals, we need a great deal more of the kind of knowledge our existing probes are gathering.

I know. I was not asking if it was likely that we'd find any but if anyone was even considering actually looking for it.

Exactly what form do you think such a search would take? Should we wander into our backyards, yelling at the sky "HELLO? Aliens? Are you there?" Should we attune our psychic powers to find them by clairvoyance? Or what?

It wasn't "change for the sake of change", it was for consistency in how we classify objects. Rather like how brontosaurus was changed to apatosaurus awhile back, although you might say "brontosaurus" is the common English name for the extinct dinosaur whose scientific name is Apatosaurus excelsus.

Nitpick: they changed their mind and concluded that the 'brontosaurus' was in fact different enough to qualify as a distinct species from the rest of the 'apatosaurus' family, so the genus Brontosaurus is back.

Yaaay!

[Borgholio]

Nitpick: they changed their mind and concluded that the 'brontosaurus' was in fact different enough to qualify as a distinct species from the rest of the 'apatosaurus' family, so the genus Brontosaurus is back.

Yaaay!

Not to take this thread on a tangent, but something similar almost happened to T-Rex. The first T-Rex fossil ever found was actually given a different scientific name, Manospondylus gigas. The next fossil found was given the name T-Rex and they were thought to be different. It wasn't until a century later that more pieces of the same original individual were found, and people realized the first fossil was actually a T-Rex too and started asking if they should get rid of T-Rex and use the old name since it came first. Turns out that since the original classification was not used more than a couple times, and T-Rex was used far more often and far longer, that T-Rex is the correct species name now. If the original name had been published more, T-Rex might actually have been renamed. Good thing it wasn't though, Tyrannosaurus Rex sounds so much cooler than Manospondylus gigas.

[Simon_Jester]

Hm... from the notes I frantically scribbled on the backs of napkins as the gentleman gave his talk... a bunch of factoids. Sorry, it's what I got.

Kuiper Belt Objects
The biggest single factor that motivated us to send a probe to Pluto was actually the same discovery that led to the IAU deeming it "notaplanet." Namely, that there are actually a great number of objects like Pluto, and objects similar to it but a bit smaller, floating around in the Kuiper Belt. Based on our current model of planetary dynamics, all these objects have existed mostly unchanged since around 3.7 billion years ago, so they tell us interesting things about the dynamics and evolution of solar systems.

Scientists now estimate that there are "tens of thousands" of Kuiper Belt objects larger than 100 kilometers in size; New Horizons is intended to examine two of them. Yes, two; there are plans to give New Horizons a lateral 'thwack' after leaving Pluto and redirect it to another Kuiper Belt object rather than just coasting directly out into interstellar space. Note that there isn't actually any funding for this yet.

But they're hoping that if they say "look, we already burned the fuel, the probe's gonna do a flyby of this random iceball in 2019 whether you fund us to learn anything from it or not, you might as well give us incrementally more money so we can collect more data because otherwise we probably won't learn anything about any Kuiper Belt objects until some time in the 2040s or so..." Well, they're hoping some funding will shake loose.

Key questions regarding Pluto, which the probe hopes to answer...

Primarily:
-What are the geology and morphology of Pluto and Charon like? Are they mostly made of rock? Water ice? Are there mountains? Craters? Big ridges? Dunes of ice crystals? Remnants of big oceans of liquid methane? Giant cryovolcanoes squirting plumes of liquid ammonia into the ultra-rarefied sky, driven by radioactive materials locked inside Pluto's core?
-What are the surfaces of these bodies made of and covered with? Organic compounds? Big piles of nitrogen hoarfrost? Rocks?
-What about Pluto's thin atmosphere of gas? We know it has one. How fast is this gas escaping? Where is it coming from?

Secondarily:
- Do the substances on Pluto's surface and in its atmosphere undergo interesting phase changes and evolve from one state to another? Or are they effectively static, eternal, and unchanging? Obviously this ties into the primary questions.
- Does Pluto have an ionosphere? How does it interact with the solar wind? Does it have a magnetic field? Does it have rings, like the gas giants but unlike the rocky inner planets? Different planets are different in these respects, and Pluto is like no other planet we've seen.
- Does Charon have an atmosphere, as Pluto does? How much is Charon like a smaller version of Pluto?

[Incidentally, the 'Pluto is red' result Purple was mocking actually helped the team address one of these questions- it has been concluded (tentatively) that the redness comes from irradiated hydrocarbons. So where did the hydrocarbons come from, and how did they come to be irradiated? How long did they have to be there for that to happen?]

Preliminary science
New Horizons already did some useful science during its pass by Jupiter to pick up speed- because its infrared cameras and ability to generate 'video' by taking a steady stream of pictures are more capable and higher resolution than anything else that's flown yet, we've been able to use it to do studies of gases in Jupiter's atmosphere evolving over time. And of volcanoes on Io, including precise measurements of the lava temperature and confirmation that there ARE many such point sources on the moon, and that the smaller ones are just as hot as the larger ones.

Furthermore, we are already getting new information about Pluto from the probe, as illustrated by the 'red' result (although with no false-color to enhance the contrast, frankly, it looks kind of beige to me). The really good stuff will come in 2016 when the download finally finishes, as mentioned in my last post.

There. That's most of what I can recall off the top of my head.

[Eternal_Freedom]

If I recall correctly, the irradiated hydrocarbons is apparently due to an interaction with either solar winds or cosmic rays. I wouldn't have thought solar winds were powerful enough that far out, but hey, before Kepler flew, I thought gas giants formed in the outer solar system, rather than all over the place.

[Broomstick]

Don't comets commonly have complex hydrocarbons? Granted, comets also tend to swing sunward (that's how we notice them usually) so they occupy different environments, but isn't it possible Pluto and comets both get hydrocarbons from similar sources?

3.7 billion years is a fuck of a long time, you don't need a strong effect or a rapid accumulation to achieve a noticeable pile of stuff over that time span.

[Eternal_Freedom]

Comets can do IIRC. You are right that on such timescales it needn't be a powerful effect. I wonder if it has something to do with Pluto's thin atmosphere?

Hmm, I guess with Pluto now being a Kuiper Belt object we can chuck that old theory about it being a captured object from another solar system. Which is a pity, but I rather liked that one.

Of course, now I'm wondering why the ages quoted for Kuiper belt objects are 1.3 billion years less than the age of the Sun, or 800 million year less than Earth's age. Curious.

[Simon_Jester]

Well, it could be captured... from another star system's Kuiper Belt. Thing is, there's no reason to favor that hypothesis over the simpler one that its from our Kuiper Belt.

Also, the age quoted in the talk was not about how old these objects were. It was about how long they have existed unperturbed in the outermost reaches of the solar system. Before that time, they may have been closer to the sun, or interacting more heavily with other celestial bodies, or otherwise subject to disturbances.

[Eternal_Freedom]

Well, it could be captured... from another star system's Kuiper Belt. Thing is, there's no reason to favor that hypothesis over the simpler one that its from our Kuiper Belt.

Yeah I know. But I always liked the captured-body idea, since it might let us directly sample something from another solar system, which would be awesome.

Also, the age quoted in the talk was not about how old these objects were. It was about how long they have existed unperturbed in the outermost reaches of the solar system. Before that time, they may have been closer to the sun, or interacting more heavily with other celestial bodies, or otherwise subject to disturbances.

Ah, my mistake.

[Iroscato]

Yeah I know. But I always liked the captured-body idea, since it might let us directly sample something from another solar system, which would be awesome.

You know, I'd never thought of that theory in that light before. That does add a new layer of mind bending to it, if it was true...

[Broomstick]

It's possible Earth has been hit by a meteor from another solar system already, which would also allow direct sampling... but we'd have to know it was from another solar system. I have no idea how that determination would be made.

[Eternal_Freedom]

It would presumably involve some chemical analysis showing that the sample in question contains molecules that are not known to have formed in this solar system, or could not have formed based on what we currently know. That's about the only way I can think of to tell.

Like, say, if the sample contained some of those weird irradiated hydrocarbons that were mentioned on Pluto, but ones that couldn't form from exposure to a normal G-type star (the Sun). Or something.

[Eternal_Freedom]

Yeah I know. But I always liked the captured-body idea, since it might let us directly sample something from another solar system, which would be awesome.

You know, I'd never thought of that theory in that light before. That does add a new layer of mind bending to it, if it was true...

Indeed. I probably also like the idea because it was mentioned in the first ever astronomy book I ever read, at the tender age of five (well, I say read, my dad read it to me, but same difference). Plus there was a random SF story where Pluto was actually an artificial object sent to observe and catalogue the universe. One of the two.

[SpottedKitty]

It would presumably involve some chemical analysis showing that the sample in question contains molecules that are not known to have formed in this solar system, or could not have formed based on what we currently know.

Not molecules, isotopes. Every solid chunk floating around out there is made of a slightly different mixture of the bits of the protoplanetary disk, so no two bodies have exactly the same proportions of isotopes. It's one of the things Rosetta discovered about comet 67P (I'm not going to attempt the full name) that raised some doubt about comet ice contributing to the Earth's water. Anything coming into the Solar System from outside is likely to have yet another range of not-quite-right isotope ratios, although the actual minerals (chemical composition only) are likely to be very close, if not identical, to what we see in normal meteorites.

[Eternal_Freedom]

Drat. At least I was on the right lines.