So you chose to stay, Now what?

[Unilyu]

Originally Posted by Woodsprite

May have been more than two years. Light isn't constant in outer space, considering how it can be weighed down by any gravity pulls from other stars it passes (Asimov). The same could exist with radio transmissions, especially if black holes are involved... then it might be possible that the transmission be received faster than 2 years; possibly 1½. We can't be sure.

Considering Alpha Centauri is the closest solar system to ours I don't think there'd be too many stars or black holes between us and it.

[Human No More]

If there was one (directly) between Earth and Alpha Centauri, then it would be unlikely that we could even see the system, and depending on the size, we would likely be able to detect the gravitational effects on Earth.

[Human No More]

Originally Posted by Ashen Key

And 4.37 years? Where did you get that? I saw somewhere instantaneous communication, but I can't remember where - so, no idea if it's accurate.

It is the distance between Earth and the alpha centauri system, travelled at the speed of light.

Originally Posted by Ashen Key

True, and I admit to being a touch more flippant with my Star Trek comment than perhaps I should have been. I'm just...attractive blue humanoid aliens with breasts push it a bit closer to space-fantasy to me.

It's called convergent evolution - there are numerous examples on Earth.
As for the mountains, it is called the Meissner effect and is physically demonstrable on Earth today. Here is an example (technically, this one is inverted for ease of cooling the superconductor, but it is exactly the same principle): http://upload.wikimedia.org/wikipedi...t_p1390048.jpg

[Raiden]

Originally Posted by Human No More

It's called convergent evolution - there are numerous examples on Earth.

^

This.

All of the things that exist in Pandoran biology that are similar to organisms more familiar to us are cases of convergent evolution.

The fact that the Na'vi have noses like those of felines is not fantasy; big cats (and housecats) use the broadened, moist surface at the front of their nose to capture scent particles more efficiently to find prey. The Na'vi hunt in a tropical rainforest climate, and it would be difficult for them to use their other senses to hunt due to the high level of sensory input; sounds from other animals, and all of the colorful plant life would make it hard to discern hidden or cleverly disguised prey items, so scent winds up being the best sense to use for hunting.

As for the Na'vi having human-like physiology, that is also convergent. Mammary glands situated higher and closer to the head allow mother animals to nurse young while being able to move more freely and sense their surroundings or keep an eye out for danger, versus mammary glands located further down the body. Also, animals that are bipedal tend not to have the capacity to carry litters of young at a time, so the number of mammary glands needed falls to the minimum, so that proteins and carbohydrates aren't wasted to produce milk that will never be needed.

The only thing that starts to cross the fantasy/reality line a little is the Human/Na'vi gene combination stuff and the passing of a hybrid's genes to his/her gametes and what would happen when (if?) a hybrid's sperm feritilized a pure Na'vi's egg (or vice/versa). The surface recognition proteins would probably allow the sperm cell access, but then things get exponentially more complicated when you consider what the sperm cell has to donate to the egg to allow the new cell to progress to a zygote and being mitotic division into an embryo. I suppose one explanation could be that for some reason the gametes produced by a hybrid have pure Na'vi DNA, while the somatic cells do not (this is actually very possible, depending on what the DNA that codes for the reproductive system/cycles is composed of). If the DNA that codes for gamete production precursors is Na'vi, then a child born to Jake and Neytiri would probably be Na'vi as well, and be a combination of the Na'vi DNA used to make Jake's avatar and Neytiri's DNA.

Whew....

/biology rant

So yeah, most of the biology in avatar is actually based on fact, and you have to dig really deep to start getting to where fact turns to fantasy.

[Ashen Key]

Originally Posted by Human No More

It is the distance between Earth and the alpha centauri system, travelled at the speed of light.

Yes, I remember that now - Sothis pointed it out.

Originally Posted by Human No More

It's called convergent evolution - there are numerous examples on Earth.

But not with breasts. Not to the point that humans have them - as far as I'm aware, we are the ONLY specie that has them all the time, and not just when nursing infants. A number of things have popped up more than once, but not that.[/quote]

Originally Posted by Human No More

As for the mountains, it is called the Meissner effect and is physically demonstrable on Earth today. Here is an example (technically, this one is inverted for ease of cooling the superconductor, but it is exactly the same principle): http://upload.wikimedia.org/wikipedi...t_p1390048.jpg

And it wouldn't affect the metal aircraft flying through it more? That's my main objection (along with the random waterfalls).

Raiden, I wasn't objecting to bipedal, or the shape of their faces (and eyes and nose over mouth make a lot of sense to me), but their breasts. PARTICULARLY as the Na'vi don't even seem to have the same level of fat on them that humans do. I mean, yes, I can roll with it for sci-fi, I just don't think it's very scientific.

[Human No More]

Originally Posted by Ashen Key

But not with breasts. Not to the point that humans have them - as far as I'm aware, we are the ONLY specie that has them all the time, and not just when nursing infants. A number of things have popped up more than once, but not that.

This isn't actually correct - on most species, they are normally a lot smaller than with humans when not actually used for feeding offspring, but they are still present. Combined with them being on the underside of many species and fur on Earth species and it is easy to think they might not be present, but they still are.

And it wouldn't affect the metal aircraft flying through it more? That's my main objection (along with the random waterfalls).

Aircraft are mainly aluminium, with some titanium and polymers.

PARTICULARLY as the Na'vi don't even seem to have the same level of fat on them that humans do.

None of them have huge breasts, the average seems to be similar to or slightly smaller than human. Fat is mostly just not distributed in the same places, and if a human lived a Na'vi lifestyle, they would have less than a typical human.

The 'hybrids' are actually more of modification of Na'vi genetic structure with appropriate human traits using human DNA as a base, and not all that implausible. The only thing with little basis in what there is today is the FTL communications, and even there, the underlying principle is understood and has been demonstrated.

[Ashen Key]

Originally Posted by Human No More

Aircraft are mainly aluminium, with some titanium and polymers.

And? I'm genuinely confused as to your point there. Because, seriously, if anyone can tell me why Trudy's Samson only has a bit of an electronic hiccups, I'd be so happy.

And the breasts thing just might to have to be YMMV - I find that the EXTENT that the Na'vi have them is exceedingly human-like (if not MORE than your average hunter-gatherer), which suggests that they have a very, very, very, very, very similar logic to their sexual selection (following on that large - for an animal - breasts for the men, large penises are for the women). I'm aware that the mammary glands themselves don't vanish (all I have to do there is to look at my own female dog), but the size and shape are odd for humans, and not at all practical without a bra (uh...yeah, just trust me on this, seriously). Neytiri's got a big enough bust that with all her of her running around, I'm surprised that the Na'vi haven't invented bras to strap their breasts down - unless the fact that Na'vi breasts don't seem to move at all is a reflection that they aren't mostly made of fat like human ones, and merely LOOK like human ones, which is still stretching coincidence a little too far for my tastes.

But, you know, YMMV, and all of that.

Although the question over communications raises another point - when was Grace's book on botany published? If it's THE book on the subject, she had to have been on Pandora to write, and had to have written in time for it to be influential before Norm and Jake left Earth, roughly seven years ago. Particularly if there IS a lag in communications anyway...

Although maybe this needs to be another thread.

[Human No More]

Originally Posted by Ashen Key

And? I'm genuinely confused as to your point there. Because, seriously, if anyone can tell me why Trudy's Samson only has a bit of an electronic hiccups, I'd be so happy.

Sorry, I thought from your post that you meant that the magnetic field would affect the aircraft's structure, when it is composed primarily of non-ferromagnetic materials. Electronics failures would not affect anything as presumably all controls are mechanical rather than fly by wire, it would just have to fly visually.

And the breasts thing just might to have to be YMMV - I find that the EXTENT that the Na'vi have them is exceedingly human-like (if not MORE than your average hunter-gatherer), which suggests that they have a very, very, very, very, very similar logic to their sexual selection (following on that large - for an animal - breasts for the men, large penises are for the women). I'm aware that the mammary glands themselves don't vanish (all I have to do there is to look at my own female dog), but the size and shape are odd for humans, and not at all practical without a bra (uh...yeah, just trust me on this, seriously). Neytiri's got a big enough bust that with all her of her running around, I'm surprised that the Na'vi haven't invented bras to strap their breasts down - unless the fact that Na'vi breasts don't seem to move at all is a reflection that they aren't mostly made of fat like human ones, and merely LOOK like human ones, which is still stretching coincidence a little too far for my tastes.

Fair enough. It's still justified from an evolutionary perspective, but it is always possible they they aren't primarily fat as in humans in that case. Either way, it isn't impossible that they did actually develop as such - if you were really so inclined, you could extend the argument to the Na'vi being bipedal and walking upright (although it is a highly adapted form suitable for many environments and especially for intelligent beings, so easily seen as a case of convergent evolution).

Although the question over communications raises another point - when was Grace's book on botany published? If it's THE book on the subject, she had to have been on Pandora to write, and had to have written in time for it to be influential before Norm and Jake left Earth, roughly seven years ago. Particularly if there IS a lag in communications anyway...

I always guessed Grace had been on Pandora for at least ten years, if not a couple of decades - look at her avatar's apparent age and it seems significantly younger than her human body, but still older than the others.

[Ashen Key]

Originally Posted by Human No More

Fair enough. It's still justified from an evolutionary perspective, but it is always possible they they aren't primarily fat as in humans in that case. Either way, it isn't impossible that they did actually develop as such - if you were really so inclined, you could extend the argument to the Na'vi being bipedal and walking upright (although it is a highly adapted form suitable for many environments and especially for intelligent beings, so easily seen as a case of convergent evolution).

*wry* I can justify it, just with a lot of 'convergent evolution' handwaving. And squinting. And possible allusions to maybe the Ancient Indian Vedes (I think it was them) are correct in their statement of 400,000 humanoid species in the universe. I just don't LIKE it. And, really, breasts not helpful in being bipedal. They bounce when you run and jump and swing through the air. This can really, really hurt, inclining the owner of said mammaries to not do such things. BUT! They make Neytiri look feminine and attractive and so I can roll with it.

Originally Posted by Human No More

I always guessed Grace had been on Pandora for at least ten years, if not a couple of decades - look at her avatar's apparent age and it seems significantly younger than her human body, but still older than the others.

Hmmm, yeah, her Avatar....I think I'd put it at closer to twenty. It's ten years for the school, which if she arrived just as that was starting, it doesn't leave any time for the book. Okay, that makes more sense.

[Banefull]

Originally Posted by Ashen Key

*wry* I can justify it, just with a lot of 'convergent evolution' handwaving. And squinting. And possible allusions to maybe the Ancient Indian Vedes (I think it was them) are correct in their statement of 400,000 humanoid species in the universe. I just don't LIKE it.

You can sum up convergent evolution like this:

There are an infinite number of ways that life can evolve but only a select few ways that are the most efficient. And if you're not efficient, you get eaten.

With the advent of computer technology, we can run simulations in which we ask a computer design a part that is the most efficient for a certain job given certain constraints and we often find that a computer generates something similar to what we see in the anatomy of other creatures. Mother nature has its ways of finding the best methods for solving problems. Eye sight evolved dozens of times during the Precambrian explosion, the wing has evolved four times (insects, birds, bats, Pterodactyls), etc.

[Ashen Key]

Originally Posted by Banefull

You can sum up convergent evolution like this:

There are an infinite number of ways that life can evolve but only a select few ways that are the most efficient. And if you're not efficient, you get eaten.

With the advent of computer technology, we can run simulations in which we ask a computer design a part that is the most efficient for a certain job given certain constraints and we often find that a computer generates something similar to what we see in the anatomy of other creatures. Mother nature has its ways of finding the best methods for solving problems. Eye sight evolved dozens of times during the Precambrian explosion, the wing has evolved four times (insects, birds, bats, Pterodactyls), etc.

I know what convergent evolution is . I'm just at a loss as to what is efficient about having large breasts, let alone why nature would pull it TWICE (and it's got nothing to do with breastfeeding, infants find it easier to nurse with smaller breasts than large) and have it scientifically believable.

[iron_jones]

Implying they can't make Avatars for the humans.

[SnowRider]

I consider Avatar to be a (mostly) "hard sci-fi" space opera with a number of fantastic elements (the "psyonic link" between the drivers and their avatars, the floating mountains, etc.) salted throughout the narrative.

It is grounded in scientific reality, for the most part, but James Cameron wasn't making a documentary nor was he trying to be "real" with the film (in my opinion) he was making.

He was making a science-fiction movie and like all movies, it is first and foremost a movie.

It is "real" up to a point, and at that point, it departs from reality and becomes fiction.

I applaud JC for most of the "hard-science" stuff in the film (the sublight transport to and from Earth and Pandora, e.g.) and I give him a pass on the rest because I recognize that he was making a movie, a made-up movie at that.

He himself has said in interviews and panel discussions that some of the stuff in the film is essentially fantasy. The explanation for the floating mountains, for example, would work fine in theory, but in reality, the magnetic fields needed to hold up the mountains would be so strong they would rip the hemoglobin molecules out of your body if you came anywhere near them.

Also, the combination of gasses in the Pandoran atmosphere would lead to a very, very bad acid rain and if you were outside in the open when it was raining, and you were wearing a t-shirt, you'd get seared by the rainwater.

Yet, we see people clearly walking around in t-shirts and we see floating mountains on Pandora.

As James Cameron has said, "the mountains friggin' float" among other things about his film. He knows it's a science-fiction movie and therefore it has to depart from reality. Avatar's departure from reality is farther down the spectrum than Star Trek, but Avatar does depart from reality.

It's a movie. Don't look at it too hard, sit back and enjoy it, and tell your inner science geek to be quiet and enjoy the movie.

That's what works for me.

[Human No More]

Again, the floating mountains are 100% hard scifi.

http://upload.wikimedia.org/wikipedi...t_p1390048.jpg
That is an (inverted) floating mountain on a smaller scale, ON EARTH, TODAY. It is only inverted for ease of cooling the superconductor. The effect is exactly the same.

Yet again - haemoglobin is NOT ferromagnetic. It does not contain molecular iron - the iron is part of a compound. Iron compounds are NOT necessarily ferromagnetic. JC made a physics FAIL there (fair enough in an offhand remark in an interview), and it does not have to and should not be taken at all literally. If a magnetic field did strip haemoglobin from red blood cells then anyone who had ever received an MRI would be dead. The field of an MRI scanner can be up to 4 Teslas, which is enough to cause magnetic objects to fly across the room and punch holes through some materials and rip metal objects out of people's bodies, but a person can survive being exposed to the field with no problems. Pandora's magnetic field is stronger than Earth's (Earth's is 0.000003 - 0.000006 T ), but still weaker than such a field.
Acid rain is extremely dependent on environmental factors - acid rain on Earth is only around 4.0 at most (lowest). While the rain on Pandora would be acidic to a degree (as is natural rain on Earth), the scale does not mean that all acids are dangerous. Anyway, the two main gases that cause acid rain, SO2 and NOx, are both primarily produced by human activity. Pandora's atmosphere is high in CO2 and H2S compared to Earth, but these are not precursors to acidity in rainwater in the same way.
Personally, I would say Avatar is far harder than ST, which is one of the harder scifi works that is widely popular (yeah, not saying much).

Originally Posted by Ashen Key

I know what convergent evolution is . I'm just at a loss as to what is efficient about having large breasts, let alone why nature would pull it TWICE (and it's got nothing to do with breastfeeding, infants find it easier to nurse with smaller breasts than large) and have it scientifically believable.

Sexual selection.
Anyway, literally every other thing in it is done perfectly, a single departure is not only reasonable, but expected in order to make the Na'vi appealing.

[Woodsprite]

Well, Cameron did note that he originally wanted Neytiri to have no breasts.