Pushing back the Alien Frontier...

[seawasp]

One development important for science-fiction authors, especially those who want to even nod in the general direction of the word "science" rather than just stick SF trappings on an adventure story (nothing wrong with the latter, of course, I write some of it myself) is that it's getting pretty much impossible now to have your newly-star travelling human beings meet up with aliens at Alpha Centauri or any other nearby stars.

Why? Because we've gotten to the point that we can detect planets around other stars for a fair distance. AlphaCent is pretty massive (and there's still argument about whether it's POSSIBLE to have habitable worlds in systems like that, I think), so detecting an Earth-sized planet by the wobble or some other means will be difficult, but if they aren't sure now, they will be very soon.

I'm not sure how far out you SHOULD put your first alien species at this point. Actually, it occurs to me there's two separate "how fars" there. The first one is "how far out should it be so that someone reading it X years from now (say, 10) won't immediately be able to say 'bah, we know there aren't any habitable planets around any star THAT close'", and the second is "how far out should it be so that it would be believable we wouldn't KNOW there were any planets there by X years from now"; that is, if your story's set 35 years from today, how far out will we have expanded our search to the point that we can be sure there aren't any habitable worlds around any of the stars (or, alternatively, how far out will we be able to determine this, assuming that any selection of destination would have been studied?)

For *my* purposes, "habitable" is basically "appears to be somewhere human beings could live roughly as easily as we can in Antarctica or better", not "human beings can live there under domes, and maybe one day could terraform it to something as nice as Antarctica, if they could move under the gravity and survive the radiation, which they can't".

Comments

[autopope.livejournal.com]

You're over-simplifying the situation enormously.

One of the important points about the current boom in extrasolar planetography is that we can mostly only detect three categories of extrasolar planet: (a) very massive ones (that cause their primary star to 'wobble' somewhat as they orbit it, causing doppler shift in their output frequency, indicating a change in the star's radial velocity), (b) ones that orbit very close to their primary (high frequency wobbles -- every few hours or days -- are much easier to detect than brightness fluctuations with a period measured in decades or centuries!), and (c) planets with orbits around their primary that directly occult the primary as seen from earth (i.e. their orbital plane is at right-angles to the direct line of sight between us and their star, so that once a year they block starlight from reaching us).

These methods are biased towards very large gas giants orbiting close to their primary -- i.e. Hot Jupiters. Earth mass planets orbiting 0.2-2.0 AU from their primary are very difficult to observe (if at all) with current techniques.

More here.

We may indeed be able to directly observe terrestrial planets within a 10-100 light year range within the next few decades, but it's a very non-trivial problem.

(Personally, I think the chances of us finding "inhabitable" planets -- by your criteria -- that we can reach are zero. That's zero for reaching them in human-feasible time, and zero for finding them in the first place. But that's another story, i.e. my next-but-one novel, and it's going to be a space opera, so you may infer that I think I've figured out a work-around ...)

[seawasp]

I thought that was true NOW, but I'm thinking in career-length terms. I.e., what will we be able to do 30 years from now? 50? 100? 30 is a short time; I've got a good chance of still being alive then.

[dsrtao]

Worldcon 2042 invites you to be GoH. You are sitting in the lobby of the High Singapore Raffles signing copies of the program and your latest book when a retropunk fan dressed as an early-2010s reality-tv contestant barges up and demands to know why you wrote about aliens from Epsilon Eridani when everyone knows that the only planet in the life zone is a volcanic mess?!

You rise to your cybernetic feet (KamenCorp PowerJog 3s) and courteously explain that at the time you were writing (a good decade before this joker was born, you note) Eridani was a perfectly cromulent candidate for a life-bearing planet, so there.

Stunned by your cogent reply, the young whippersnapper slinks off in search of an easier target. #$EridaniFail is a subject of controversy for hours, leading to excellent sales of t-shirts bearing a video of the incident.

[seawasp]

I prefer my science to be invalidated on longer timescales.

Of course, with Boundary and Threshold, the invalidation timescale isn't decades, it's months or a few years.

Asimov as Paul French

[wswears.livejournal.com]

Asimov wrote a lot of stuff that proved unfounded in later years. Lucky
Starr and the Pirates of Venus had Venus as a water world with intelligent frogs. His response was to shrug and say he'd write it differently today.

Since we're fairly aware that planets will be discovered, you can either let reality overtake you, or use good science as we know it on a fictitious star that sits closish. If you think putting your planet with life on it close-by is useful.

Personally, I'm probably going to pick star that absolutely cannot have a habitable planet circling it, then let my characters grouse and complain about it being both impossible and "right over there."

Bill

[purplekitte.livejournal.com]

The Fermi paradox really is depressing. Though at least it's probably easier to detect Jovians than terrestrials, so people could believe missing one, not to mention moons.

[seawasp]

The Fermi Paradox isn't. It's a pretty meaningless handwave that rests on so many unknowns that you can assume just about anything. It's fun to play with as a writer, and since I know *SO* much of fandom (and writerdom) has accepted it pretty much as gospel, I make noises in its direction to at least quiet the protests to a dull roar, but I find it a completely unimpressive thing -- no more meaningful than the Drake Equation until we can quantify at least four or five of those terms.

[purplekitte.livejournal.com]

Eh, I usually hear the term used as a shorthand for 'Space is big but we haven't yet seen any aliens we can communicate with. Too bad (or possibly very lucky, depending on what they're like).'

gliese 581 g

[niall-shapero.livejournal.com]

A reasonable bit of info on Wikipedia (at http://en.wikipedia.org/wiki/Gliese_581_g). A terrestrial-like planet (at least potentially) in the "goldilocks zone", with a surface gravity likely something that humans could tolerate (at least for a time - something from 1.1 - 1.7 gees). Of course, it's likely tidally locked (it's orbiting at a distance of roughly 0.146 AU and has an orbital period of only 37 days), but it could still be something that people could survive on (assuming that we brought tanked air - there's no guarantee that any atmosphere would be breathable).

[aardy.livejournal.com]

There is another option: (Call it the "Smith-Raymond Theory")

The aliens have figured out how to turn their entire planet into a spaceship. So just because scientists have proven there are no Earth-like planets around a particular star doesn't mean there can't ever be an Earth-like planet around that particular star.

E.g.:
"Sir, Alpha Centauri has begun to wobble! What does it mean?"

"Let's outfit our newest starship with a hand-picked crew and go find out..."

And, of course, the ever-popular:

"That's not a moon, it's a space station!"

[kengr]

Fritz Lieber's "The Wanderer" Late 60s or early 70s, I'm too lazy to look up the publication date.

Only it's not a wobble in Alpha Centauri that's detected. It's their Earth-sized ship arriving in the solar system.

[kengr]

A lot depends on if we keep dragging our feet about space exploration or if we actually get off our asses and start doing significant numbers of probe launches and get more folks in space (even a bunch of folks in LEO will make a difference).

Consider that a relatively cheap *amateur* telescope becomes world class if you are using it above the atmosphere.

If we have lots of half meter or so scopes in LEO with any sort of decent instrumentation, we'll get stars checked out a lot faster.

If we can get some hubble class scopes scattered across the solar system, things get even better (or worse depending on your point of view).

Heck, I really need to consolidate the posts I've made to the Traveller Mailing List over the years about the way stellar surveys and mapping will work for a culture that has routine access to space and common FTL.

It's a major game changer. For example, place some observatories in to outer reaches of a couple of systems a parsec or so apart, and wait the decade or so it'll take for a bidirectional laser link between them to get calibrated so they can synch observations and know how far apart they were when observations where made.

a one *parsec* baseline (as opposed to our current 2 AU one) means that you can pin down locations of stars a *long* ways off. Add in huge telescopes (either huge mirrors or multiple mirrors) and you can likely spot planets themselves a few dozen parsecs off.

That makes exploration a *lot* different from the assumed "jump into the dark and hope you come out close enough to the target star and that it has planets you can do anything with" model you see in most things.

[johnkzin.livejournal.com]

Have you picked up Stephen Kent's 'Clone series'? (Starting with "Clone Republic")

Worth the read. And I like how he handles the whole topic, but I wont spoil it for anyone who hasn't read them.

[ath-winter-lord.livejournal.com]

35 years from now? I'd expect the bigger problem to be "how do they get there".

My Space thing is set somewhere beyond year 4800 (at a rough estimate), and by then potential destinations no longer have the same names as we know, and I don't give distances or locations.

(Humans have continuously failed to leave the solar system until then, for reasons that are to be revealed in the story. I know them, mind, it's part of the backround/setting. The new 'drive' is something anyone today would call loony, but today things that aren't known, or even not known to be not known, are in the majority. For that 'drive' distances are irrelevant. What matters is nearby bodies, of start and destination; shouldn't be too near anything massive.)

Plus, there's that backround/setting, with which I could make any system what I like, while looking quite different from within the solar system. (Basically, what's seen from here may just be fake data.) But I'm not doing that, it's just an option.

Reading comments, what's the Fermi Paradox?

[seawasp]

In its simplest form, it's roughly "Any intelligent race could expand through its galaxy and even local cluster in a very short time, astronomically speaking; yet we've seen no sign of any aliens. So where are they?"

The paradox part being that it seems hard to believe that we are utterly unique -- there's no particular reason to believe that the Earth is somehow uniquely special -- yet if we aren't unique, the likelihood that we're the first intelligent species is pretty low, so the aliens SHOULD have gotten here, even by slow-speed methods. But they aren't here, as far as we can tell.

It is, to my mind, a pretty weak paradox and makes all sorts of assumptions that aren't any stronger than others that could be made.

[johnkzin.livejournal.com]

For one, other species might be having the same problem we are: justifying the initial cost (and assumed lack of initial profit) of making the leap to space.

"Why bother? The star we live near will be here for a good long time still, the cost of leaving, the cost of harvesting remote resources, the sheer huge impossibility of even getting to the really remote resources ... just doesn't add to the best investment I can make with my money today. Sure, it'll be a boon for our great grandchildren ... but that wont convince my voters/stock-holders today."

Something has to come along and disrupt that mindset. We haven't been hit with that disruption yet (at least, not in a big enough way to get us to be convinced to reach for the stars in a bigger way), why should we assume other species aren't having similar issues?

[ath-winter-lord.livejournal.com]

Thanks.

I, for one, would ask "Why should they come here?"

Well, that's the second thing that comes to mind, the first is the astronomical timescale. Why should they happen to be around in just the window we are?

After all, let's say they expand by generation ship (the ones that made it to a point they're able and willing to set out in them). And a few ships even don't fail before they find a planet that's habitable, who's to say the planet doesn't fail (as in, the system's star gets old and goes out with a firework) before 'we' get a look at it.

And, cruising around in generation ships, even with a few more that don't fail over the astronomical timescale (they could be hopping from system to system, until each planet/star fails), why should they happen to pass by just the moment we take a look?

And if they did spot Earth, and decided to head this way, and came here a few tenthousand years ago, why didn't they move in?

(I'd want real answers to those questions, not ones that look good - to some people - in a story...)

Space is, after all, infinitely big. It's expecting something relatively rare (I assume) happening not only in close physical proximity, but also in close time-proximity (for lack of a better word).

At a guess, I'd think it's more probable for me to run into you at the grocery store next time I'm there, or even any time, anywhere I go in this city.

"Stars" with planets

[niall-shapero.livejournal.com]

If you've checked the list of exoplanets, there have been planets found around a frippin' PULSAR! (PSR 1257+12). There's a list (I assume reasonably up-to-date, but you might want to check it against other lists) at: http://exoplanets.org/exotable/exoTable.html. I've been going through and converting right ascension & declination values for the exoplanet systems into galactic coordinates, and from there into cartesian coordinates (Ok, so my RPG background is showing, again... :-)).