Exploding Stars Led To Humans Walking On Two Legs, Radical Study Suggests (theguardian.com) 170
dryriver shares a report from The Guardian: It was the evolutionary leap that defined the species: while other apes ambled around on all fours, the ancestors of humans rose up on two legs and, from that lofty position, went on to conquer the world. The benefits of standing tall in the African savannah are broadly nailed down, but what prompted our distant forebears to walk upright is far from clear. Now, in a radical proposal, U.S. scientists point to a cosmic intervention: protohumans had a helping hand from a flurry of exploding stars, they say.
According to the researchers, a series of stars in our corner of the Milky Way exploded in a cosmic riot that began about 7 million years ago and continued for millions of years more. The supernovae blasted powerful cosmic rays in all directions. On Earth, the radiation arriving from the cataclysmic explosions peaked about 2.6 million years ago. The surge of radiation triggered a chain of events, the scientists argue. As cosmic rays battered the planet, they ionized the atmosphere and made it more conductive. This could have ramped up the frequency of lightning strikes, sending wildfires raging through African forests, and making way for grasslands, they write in the Journal of Geology. With fewer trees at hand in the aftermath, our ancient ancestors adapted, and those who walked upright thrived.
According to the researchers, a series of stars in our corner of the Milky Way exploded in a cosmic riot that began about 7 million years ago and continued for millions of years more. The supernovae blasted powerful cosmic rays in all directions. On Earth, the radiation arriving from the cataclysmic explosions peaked about 2.6 million years ago. The surge of radiation triggered a chain of events, the scientists argue. As cosmic rays battered the planet, they ionized the atmosphere and made it more conductive. This could have ramped up the frequency of lightning strikes, sending wildfires raging through African forests, and making way for grasslands, they write in the Journal of Geology. With fewer trees at hand in the aftermath, our ancient ancestors adapted, and those who walked upright thrived.
I would tend to theorize standing tall (Score:2)
on 2 legs overlooking the grasslands, and in thunderstorms would probably be less successful as survival strategies go.
On the other hand, you can run away from fires more quickly on 2 legs (for humans)
Re:I would tend to theorize standing tall (Score:4, Informative)
Four legged animals are much faster runner than two. What walking on two legs gets is less energy expended for distance traveled. One of the most effective hunting technique for early humans where to chase animals by walking after them until they collapse from exhaustion.
Re:I would tend to theorize standing tall (Score:5, Informative)
There is pretty good evidence which demonstrates this. While we suck at high speeds over short distances, humans have adaptations which make us incredibly efficient at running at variable paces over long distances and particularly in the heat.
1) Our breathing is decoupled from out gait unlike other animals
2) Our running economy doesn't change that much over a wide variety of paces, whereas animals are locked into a small set of pace ranges
3) We sweat very effectively in the heat
All of these make us very good at running animals until the either stop or die from heat exhaustion.
Re:I would tend to theorize standing tall (Score:4, Informative)
A lot of this is the type of muscle. Human muscle tends to be slower but much more energy efficient than say cat "fast twitch" muscle which can generate radical speeds (seriously, watch a house cat run and then leap a fence in one hit, cats are forces of nature, but that muscle burns rapidly out, meaning a cat has to spend most its day resting and recuperating. Cats have terrible endurance compared to dogs and humans. They where built for doing low energy lightning ambushes on prey, whereas humans and dogs where built to run prey down even if it means casually jogging after them for a day until the prey keels over from exhaustion
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Stake a bitch in heat out overnight in a wolf area, you'll get a pregnant bi
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Humans have 2 main forms of skeletal muscle fibre too, slow and fast twitch. People with a higher percentage of fast twitch , eg sprinters, weightlifters etc , tend not to be all that great at endurance exercise such as marathons either.
Humans can also be incredibly strong. There are plenty of vides on youtube of small weightlifters lifting twice or more of their body weight above their heads.
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This is trainable though. Humans, naturally, have a balance of slow twitch and fast twitch muscle fibers. While to some degree this is genetic, sprinters and weight lifters don't have a higher percentage of fast twitch simply from nature, rather they train those energy systems to perform the way they want. And again, within limits of genetics, almost anyone who is a typical fast-twitch person can retrain their bodies to have a higher slow twitch balance. And vice versa. Look at a guy like Ryan Hall, wh
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"sprinters and weight lifters don't have a higher percentage of fast twitch simply from nature"
Err yes, they absolutely do. Its what differentiates olympic athletes from the average gym bro.
"Look at a guy like Ryan Hall,"
What about him? A 66kg sack of bones with a bit of stringy muscle looking at the pictures. Picking up big weights my arse. And if you call that bulked up god knows what you call skinny. This is someone who's bulked up:
https://barbend.com/strongman-... [barbend.com]
Sweating is a good strategy until... (Score:2)
... you run out of water. And you do that pretty quick sweating profusely. Sure, you can carry it but there's only so much water any one person can carry as its heavy stuff so our ancestors would have had to stay pretty close to sources of water on any long hunts in the savanna. IMO sweating and long hunts in the heat don't dovetail all that well.
Re:I would tend to theorize standing tall (Score:5, Informative)
What walking on two legs gets is less energy expended for distance traveled
It also leaves the arms free to carry stuff, like a container with water, or a weapon, and it exposes a smaller area of the body to the sun. Here's a tribe still using the method: https://www.youtube.com/watch?... [youtube.com]
Re:I would tend to theorize standing tall (Score:4, Funny)
I think the "being able to carry stuff" part is the reason humans learned to walk upright and every other reason is wrong.
Human with stick? Winner.
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I think it's a combination of multiple reasons, reinforcing each other to exploit a particular niche. Regular 4-legged animals don't carry stuff with their front legs, because it would be terribly inefficient given their body structure. An animal already needs to be walking on two legs regularly and reasonably efficiently, so that the additional of an extra tool would not be a huge disadvantage.
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Genes get passed when you get laid. Carry food hom (Score:2)
> also leaves the arms free to carry stuff, like a container with water, or a weapon
Certainly true. Humans are slow, weak, have bad eyesight, horrible hearing ... we pretty much suck as animals go and make good prey - until we have a weapon in hand. A weapon makes all the difference.
Also, he who gets laid the most passes on his genes the most. Carrying food and water home might be real attractive to prehistoric babes.
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In bright sunlight if it doesn't move (Score:2)
Dogs can detect moving objects (aka animals) 10-20 further out than humans can. Humans are better at starting at a far-away object that doesn't move. The dog will see us coming long before we see them.
Around sunset, we go mostly blind, in contrast to most other animals.
We do see color (in the daylight) better than most animals, though not nearly as well as birds of prey such as eagles, hawks, and falcons, or shrimp.
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What walking on two legs gets is less energy expended for distance traveled.
I don't know a single dog that can't out-walk you.
Re:I would tend to theorize standing tall (Score:4, Interesting)
I don't know a single dog that can. :) but dogs? They NEED to stop.
Let me know if you see a dog that can walk continuously for 12 hours at any pace, the condition being to never stop. Most human beings can do it, even untrained, except for the sick and the obese. It would be tiring, of course, but nevertheless possible. Dogs? They will become exhausted, at a minimum they need to stop to eat and drink water, whereas a human being can do both while walking. Excretion is indeed difficult for a human to perform while walking, not without soiling oneself
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Re:I would tend to theorize standing tall (Score:4, Informative)
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Then you don't know many dogs. An athletic dog will get tired out before an athletic person. A small dog will get tired after a couple miles. Sometimes humans can outrun horses, too. [wikipedia.org]
My dog lies around panting for an hour like he's run a marathon after we get back from the shop, it's only a 20 minute round trip.
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My dog lies around panting for an hour like he's run a marathon after we get back from the shop
And the advantage of humans sharply increase in hot weather, such as noon in Africa. Our ability to sweat, bare skin, and upright position help a great deal to get rid of excess heat. Humans also have relatively long tendons that work as springs, and fairly low muscle mass compared to other apes, lowering energy (and heat) expenditure when running long distances.
Re:I would tend to theorize standing tall (Score:5, Informative)
"Humans grew tall because they loved looking at the stars and grew tall so they could be closer to them. And now in cities we deny and turn away from our evolutionary past, we cannot look at the stars."
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lol it's a "meerkat".
anthropology (Score:3)
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4) If electric force propagated infinitely fast
It doesn't.
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How fast does it propagate?
Roughly 10% of the speed of light.
4c) Does something else propagate as fast?
Yeah light goes a lot faster.
Re:anthropology (Score:4, Informative)
Roughly 10% of the speed of light.
No. Electricity through a conductor may propagate that fast, but the electromagnetic/Lorentz force propagates as the speed of light, and is subject to the rules of relativity.
Yeah light goes a lot faster.
Light is a manifestation of the electromagnetic force. It can't possibly go any faster.
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Light is a manifestation of the electromagnetic force. It can't possibly go any faster.
Not even if we rub cheetah blood on it? ;-)
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Electricity through a conductor propagates at the speed of light [wikipedia.org] in the conductor, which depends on the relative permittivity (eps_r) and relative permeability (mu_r) of the medium. Relative to empty space. In the air where both eps_r = ~1 and mu_r = ~1, the speed of light is the same as its speed in free space.
Most conductors that carry electricity have mu_r=1 but eps_r > 1, typically < 10, which tends to slow down the speed of light in said conductor. A typical rule of thumb for propagation speed of
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1) Does an electric force exist?
No, it is an illusion. What exist is a gradient of the potential.
2) Does matter oscillate?
No, it doesn't. But there are some processes that are, in the approximations we can solve, best described as oscillators.
3) Does resonance exist?
No, but there is a probability for interaction that behaves like "resonance" if your model is a "vibration". See above.
4) There is no electric force
5) You're an idiot.
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No, it is an illusion. What exist is a gradient of the potential.
Completely wrong.
No, it doesn't. But there are some processes that are, in the approximations we can solve, best described as oscillators.
Completely wrong *again*.
No, but there is a probability for interaction that behaves like "resonance" if your model is a "vibration". See above.
Holy shit, you're really on a roll. Wrong again.
4) There is no electric force
Yes, yes there is. More specifically, the electromagnetic/Lorentz force- literally one of the fundamental forces of nature, that gauge boson of which being the photon.
In summary, wrong again.
5) You're an idiot.
Well, that's complicated. He comes off as a subscriber to plasma cosmology, which makes him wrong, but his questions compared to your answers indicates he is *far* more intelligent and knowledgeable than you.
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1) Does an electric force exist? 2) Does matter oscillate? 3) Does resonance exist? 4) If electric force propagated infinitely fast, and those oscillations push on each other with that force, would that oscillating system become resonant? 5) And if you move one piece of that oscillating resonant matter and pushed another piece of that oscillating resonant matter, how fast would the oscillations propagate across the oscillating matter? 6) So how fast would the oscillating version of that electric force propagate? 7) And could you have resonance at the harmonics, e.g. F/2? 2F? 8) And what would they look like if they existed?
Yes
Answers the ancient question (Score:5, Funny)
As cosmic rays battered the planet, they ionized the atmosphere and made it more conductive. This could have ramped up the frequency of lightning strikes, sending wildfires raging through African forests, and making way for grasslands, they write in the Journal of Geology. With fewer trees at hand in the aftermath, our ancient ancestors adapted, and those who walked upright thrived.
Turns out, not only is there a God - He is Rube Goldberg. Or Rube Goldberg was He, take your pick.
I am now soliciting donations now to build the Church of the Eternal Contraption.
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Something seems a bit off with the timeline there... :-)
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That's been done already [wikipedia.org].
A god ? (Score:2)
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In case you need it (Score:2)
Re:Answers the ancient question (Score:4, Funny)
I hope the Church of the Eternal Contraption (CEC) allow for virgin sacrifices and head decapitations.
Yes, though the device must perform at least 200 distinct steps to complete tasks of a more serious nature, the head can be used as part of the Contraption but only after step 74 (74 holds mystical significance within TCOTEC).
I want a vengeful God that demands sacrifice, and naked worship of Snake Gods
Just a word of advice you probably do not want to be naked anywhere near the more complex Contraptions, in fact you are encouraged to buy the Holy Googles Of Safe Viewing ("They Do Something!") at the entrance.
ooh, radical... (Score:4, Insightful)
You had me right there.....
Not.
Proof... (Score:1)
Tired of tabloid science (Score:5, Insightful)
First, here is the link to the actual article.
https://arxiv.org/ftp/arxiv/papers/1903/1903.01501.pdf
Second, here is the argument put forward in the paper... in its entirety:
>The conversion from woodland to savannah has long been held to be a central factor in the evolution of hominins to bipedalism, although more recent thinking tends to view it as a contributing factor (Senut et al., 2018). Thus, it is possible that nearby supernovae played a role in the evolution of humans.
So, apparently these scientists aren't even the originators of this idea as they reference others. Second, there is NO science here, just a speculative hypothesis.
Third, the media needs to stop looking for grabby headlines when it comes to science. Every break room will have people "teaching" each other about how "lightning caused us to walk upright" and every school will have kids asking confused teachers, "Did you know lightning made us walk on two legs?" as if it's some established fact.
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Second, there is NO science here, just a speculative hypothesis.
Science is a bunch of "speculative hypotheses" with enough evidence to back them up at a preselected confidence level.
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Re:Tired of tabloid science (Score:4, Interesting)
If you say it like that, it sounds like science doesn't experiment.
Experimentation is not central to the scientific process, it's a peripheral tool.
The core of the scientific process is precisely the speculative construction of falsifiable hypotheses that are simple, broad explanations of many interacting phenomena, then working out ways to test them through observations. When we can carefully design and construct the observation-generating apparatus to give us exactly the observations we need, we do. That's experimentation, and it's by far the most efficient way to gather useful observations.
When we can't experiment, because the phenomena we're trying to study happened long ago, or far away, or are too big for us to manipulate, we use other, messier methods. These other methods often involve measuring proxies which provide second- or third-hand evidence and which are themselves influenced by other factors that need to be controlled for. This is much harder and slower than direct experimentation, but it's no less scientific.
If this is interesting to you, I highly recommend that you read David Deutsch's "The Beginning of Infinity". He does a much better job of explaining this than I could, and in an entertaining way. Along the way he makes a strong argument that science is no more and no less than a rigorous and efficient version of memetic variation and selection, fundamentally the same process as evolution but in the realm of ideas rather than biology, and many orders of magnitude faster. From that he hypothesizes that variation and selection is the only knowledge-creation mechanism that exists. I'm not sure if that's profound or a tautology, since "knowledge" in the sense that he uses it isn't a well-defined term. In any case, it's a fascinating and thought-provoking book; well worth your time.
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Experimentation is not central to the scientific process, it's a peripheral tool.
Hm. I feel violated here. I can twist myself to see it the way you are describing, but it is indeed twisted.
Experimentation validates.
It is what takes Science from a combination of Math and Philosophy into the realm of physical reality.
Science without experimentation is pure mental masturbation. To put it another way:
In theory, theory and reality match up. In reality, not so much.
Experimentation is necessary to falsify theories that, in theory, are correct.
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You can call them "experiments" or you can call them "careful observations" but they're basically the same thing. What astronomers do with telescopes are called experiments, and they're not significantly different from what happens in a lab: they come up with a hypothesis, and they come up with a way to test that hypothesis by controlling for as many variables as possible. Scien
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The core of the scientific process is precisely the speculative construction of falsifiable hypotheses that are simple, broad explanations of many interacting phenomena, then working out ways to test them through observations. When we can carefully design and construct the observation-generating apparatus to give us exactly the observations we need, we do. That's experimentation, and it's by far the most efficient way to gather useful observations. When we can't experiment, because the phenomena we're trying to study happened long ago, or far away, or are too big for us to manipulate, we use other, messier methods. These other methods often involve measuring proxies which provide second- or third-hand evidence and which are themselves influenced by other factors that need to be controlled for. This is much harder and slower than direct experimentation, but it's no less scientific.
I doubt we have any particular disagreement here, it's mostly a matter of how we draw boundaries on words and definitions, so I don't see value discussing this (if you disagree, of course let me know).
If this is interesting to you, I highly recommend that you read David Deutsch's "The Beginning of Infinity". He does a much better job of explaining this than I could, and in an entertaining way. Along the way he makes a strong argument that science is no more and no less than a rigorous and efficient version of memetic variation and selection, fundamentally the same process as evolution but in the realm of ideas rather than biology, and many orders of magnitude faster. From that he hypothesizes that variation and selection is the only knowledge-creation mechanism that exists. I'm not sure if that's profound or a tautology, since "knowledge" in the sense that he uses it isn't a well-defined term. In any case, it's a fascinating and thought-provoking book; well worth your time.
This looks interesting. Did he give any insights that would help one find better hypotheses? Or jump out of the 'normal' path?
On the other hand (Score:5, Interesting)
One theory that I always enjoy was put forth in the early 70's by Elaine Morgan. Her books are a great read (go in with an open mind); The Decent of Woman, The Aquatic Ape, The Decent of the Child, etc.
I like the way she lists specific attributes (like a subcutaneous fat layer in a land mammal, the shape of the human nose, where we lost hair and where we retain it) and then points out how those would make sense (evolutionarily) if we lived most of our lives in the shallow water around coastlines (for tens of thousands of generations).
I never was a big fan of The Mighty Hunter theory, with us standing tall to see those animals we were about to kill.
Ah theories....
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those would make sense (evolutionarily) if we lived most of our lives in the shallow water around coastlines
That sounds really interesting, also explains why people are so drawn to swimming and baths!
Will have to look that up, thanks.
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Yeah, it explains a number of features humans have that our closest relatives lack.
For example, consider that chimp's feet are basically the same shape as their hands, yet we have big flap flipper-shaped feet.
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That should red *flat flipper-shaped feet. Also note that there are other bipedal species, but we are the only ones whose feet are shaped like flippers. Most bipedal animal have long splayed toes with a big central toe on each foot (ostrich, emu, kangaroo etc). So there doesn't, on the face of it, seem to be a reason that bipedalism would necessarily select for feet shaped like ours. But natural selection for swimming ability might.
Re:On the other hand (Score:4, Insightful)
Hypotheses. Not theories.
And having an open mind is fine, but it doesn't mean you should drain your brain from your skull.
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Yup, and conscious control of breathing is apparently something else that's common in aquatic animals, but rare in non-aquatic ones. And apparently apes often stand quite upright when wading through water, but seldom do so otherwise, so bipedalism is something that could quite reasonably be expected to develop in aquatic apes. There's a lot in there that makes sense to me.
I might not recommend The Descent of Woman. As I recall, I thought there were some attempts to link to feminism that I found a bit que
Re:On the other hand (Score:4, Interesting)
like a subcutaneous fat layer in a land mammal
Like in chimps? [nih.gov]
When they measure skinfolds on chimps to ascertain obesity in chimps - that's what they are measuring. Subcutaneous fat.
Also, that "paunch" [google.com] you'll see [blogspot.com] on apes and monkeys [theguardian.com] - all those folds are subcutaneous fat.
But why even bother with apes?
Just go to your local supermarket and take a look at some bacon. [sciencedirect.com]
Aquatic ape theory is pseudoscience based on 1930s understandings of evolution. [wikipedia.org]
Everything it posits is either just plain wrong or more adequately explained by other theories or plain observations.
Like that bit about humans evolving tool use to crack shellfish - when tool use is widespread among various animals. [livescience.com]
Particularly those fuckin chimps. [youtube.com]
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That's a bit different to the aquatic ape theory which says that a human ancestor evolved with a watery environment as their primary environment.
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The subcutaneous fat layer is valuable for a hairless ape, on its own. But clearly it is valuable whether early hominids were swimmers or distance walkers or distance runners.
What I find compelling is the shape of our nose, which does not seem to have any positive value except for creatures who wade in water a lot and dip their face in the water. There are lots of noses out there for critters that are better at smelling and better at running for their lives on a hot savannah, and none look anything like o
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it was the monolith (Score:4, Insightful)
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At last! (Score:1)
Correlation versus causation (Score:1)
Coincidence Does Not Equal Causation (Score:3)
We do know that several "nearby" supernova explosions did occur in about the 3Ma timeframe. Suggestions that this CAUSED our pre-human ancestors to stand erect ..... Well, some people have watched "2001: A Space Odyssey" a few too many times.
drought could have done that (Score:3)
Reasons (Score:4, Funny)
I don't know about the rest of y'all, but I have to walk on two legs because when I walk on four my dick keeps dragging on the ground.
Just sayin'.
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Mommy was hooked on thalidomide?
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Sounds like you pee sitting down. Wuss.
If you pee standing up then sooner or later you're going to get some outside. Just the way it is.
It is really bad form when some guys totally miss the target and get the floor wet. You get that gas station type smell.
Then they came up with the flushless urinals.... gas station smell all the time!
How do you spell (Score:2)
"Sheer speculation"?
Radical? (Score:2)
Ludicrous theory seems more appropriate.
Mind you, exploding stars did lead to humans walking upright, in a straightforward way. Without exploding stars there wouldn't be anything heavier than hydrogen and helium to stand on , and hydrogen isn't very suitable for standing on.
Maybe (Score:2)
Or maybe we stood up because it was better for wading.
Not convinced (Score:2)
Reforestation after a fire happens pretty rapidly so I don't think evolution would get the chance to produce a grassland oriented creature in that sort of timescale.
30-50 years after any fire, the forest would be back again.
I see (Score:2)
It was so bright, that they needed the hands to cover their eyes.
Carl Sagan back from the dead? (Score:2)
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"We are all made of Stars"
-Moby
what was that? (Score:2)
The endless 'Just So' stories (Score:2)
Conjecture over conjecture over conjecture (Score:2)
Imploding Intelligence (Score:2)
A better headline:
Imploding Intelligence Led to a Few Humans Thinking Exploding Stars Led to Humans Walking on Two Legs, Ordinary Study Suggests.
Next stage of humanity (Score:2)
sending wildfires raging through African forests, and making way for grasslands, they write in the Journal of Geology. With fewer trees at hand in the aftermath, our ancient ancestors adapted, and those who walked upright thrived.
I can't wait to see what all these Hollywood Hills people evolve into!
Woah! (Score:1)
Why aren't there more bipedal species? (Score:2)
Next time (Score:2)
So when Betelgeuse goes off, we'll grow tentacles? I'm getting a jump on the change and purchasing stock in Japanese smut.
This is nothing... (Score:2)
...but a good story. It is not science.
More likely.. (Score:3)
Study? (Score:2)
Bong or something involved forming theory (Score:2)
SCIENTIST ONE: (Exhaling cumulus sativa cloud): "Dude! Like, what if, like, stars started blowing up and stuff and, that, like..."
SCIENTIST TWO: (While applying spark) "That's like a ton of earth-flame dude, like, people had to run away man."
SCIENTIST ONE: "Total Metallica video back then, so we're all running and like the other monkeys are all 'wait for me brah'"
SCIENTIST TWO: (pointing at his own legs on the couch, as bubbling sounds emanate elsewhere) "I got two long legs and you got four little arms. Su
Caucas mountains? (Score:1)
So why does this have to be Africa? If they're going for a radical new theory, place it in the Caucas mountains where it probably happened (geography, etc). Stir the pot? Stir it good!
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