Science Tidbits #5

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Re: Science Tidbits #5

Postby RJDiogenes » Sun Sep 03, 2017 9:07 pm

Lupine wrote:Some 5.7 million year old tracks have been found.... in Crete! :jawdrop:

That's fascinating. Things keep getting pushed back, it seems, which is not only interesting on its own merits, but it makes recent evolution all the more compelling (and perhaps extraterrestrial intelligence even less likely by extension).

Granted as the author points out the Mediterranean had mostly dried at that point, allowing someone to literally walk from Africa to Europe, but this is likely evidence of the oldest Hominin (the group formally known as Hominids) outside of Africa. The article points to the possibility of Hominins originating in Europe but I think it's a little too early to assume that. Still this is a very early horizon and shows that our ancestors were far more cosmopolitan than previously assumed.

There's pretty much no good evidence of a European origin and what little evidence there might be could certainly be explained by earlier migrations. Which is not exactly far fetched-- there's no reason that it would take a million or more years for a hominid group or groups to migrate to Europe, especially with a dry Mediterranean. It could happen in a century or less, which is an immeasurably small time at these scales. The real story is probably a complex web of multiple migrations, interbreeding, and local extinctions over millions of years.

But it does bring the question to mind: These footprints were made just at the time the Mediterranean was flooding again. What came of those trapped on the island? :unsure:

They evolved into Minotaurs, maybe? :unsure:
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Re: Science Tidbits #5

Postby Lupine » Sun Sep 10, 2017 6:48 pm

A fun (and scary) graph someone posted on Democratic Underground.
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Re: Science Tidbits #5

Postby RJDiogenes » Sun Sep 10, 2017 8:09 pm

They missed their opportunity for a good Brexit joke around 6500 BCE.

I wonder what this graph would look like if it were pushed back to those 5.7 million-year-old footprints in Crete. Or back to the extinction of the dinosaurs.
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Re: Science Tidbits #5

Postby Lupine » Mon Sep 11, 2017 3:11 pm

That would be interesting as Earth has gone through some pretty significant climate upheavals. It was significantly warmer than today before and after the K/T boundary (likely due to the eruption of Deccan).
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Re: Science Tidbits #5

Postby RJDiogenes » Mon Sep 11, 2017 10:22 pm

That's what I was thinking. Contemporary climate change is no danger to the ecosphere as a whole, even though it would be mighty devastating to humanity if it got dinosaur-era warm again.
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Re: Science Tidbits #5

Postby Lupine » Mon Sep 11, 2017 10:52 pm

^Yeah, almost the entire equatorial region of Earth would be uninhabitable by humans. But then again global warming at the end of the Permian (due to Siberia erupting) wiped out 90% of all life on the planet. :Ahhh:
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Re: Science Tidbits #5

Postby huggle » Tue Sep 12, 2017 10:21 am

^while nowadays we do the very same without any help from nature at all.
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Re: Science Tidbits #5

Postby Lupine » Tue Sep 12, 2017 3:04 pm

^That's the scary part. The Earth got through the Permian, but the sun was cooler back then. So we have no idea where the tipping point is today for a runaway Greenhouse effect (think Venus).
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Re: Science Tidbits #5

Postby huggle » Wed Sep 13, 2017 4:57 am

indeed. The greenhouse effect is not only based on the ozone hole, exhaust fumes and other direct causes. There are many indirect ones that tend to get overlooked:
Many people are conscious of the problem of deforestation. Forests act like huge air condition devices. They cool the air down in summer, warm it in winter and break storms all year round. They also act like sponges, storing water in times of surplus and giving it off gradually, thus keeping both the ground and surface water levels steady. The unusual flash floods we Europeans have been experiencing for the last years have their root in deforestation and sealing off all available surfaces with concrete or tarmac.
Another important factor that is less publicly known is the ever growing (pardon the pun) corn/maize market. Nowadays maize is not only used for feeding livestock but mainly for feeding organic gas plants. The area on which maize is grown in Bavaria nowadays is about twenty times as large as it was a decade ago and in other regions it's similar. Maize, however, is not at all suitable for mountanous or even hilly country. Between the rows the soil is open and unprotected. Extreme erosion is the consequence. This way the microorganisms that live in the upper layers of the soil get washed away and in the lower soil levels they are unable to live. This is not only devastating for the crop but also for the climate as these microorganisms are responsible for most of the planet's oxygen production on land.
In the sea the situation is similar: oxigen is produced by algae so you might assume many algae mean a lot of oxygen. Unfortunately, algae produce oxygen only during the day. At night they breathe it in again. Also, when algae die and rot, a lot of oxygen is used up. The consequences are apparent in the gulf of mexico where there are huge marine areas that are completely dead, except for the surface where the water can suck oxygen from the atmosphere. And these dead zones are growing rapidly every year, a fact that causes great concern both in marine biologists and climate researchers. (here at least the hurricanes are actually a blessing: they stir up the sea and distribute oxigen into the lower water layers)

On the whole, the impact of plant life on the climate and ist changes is imo vastly underrated.
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Re: Science Tidbits #5

Postby RJDiogenes » Wed Sep 13, 2017 9:39 pm

We must all buy more plants. :mellow:
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Re: Science Tidbits #5

Postby huggle » Fri Sep 15, 2017 5:40 am

good bye, Cassini! :(
If you'd like to watch the probe's last trip, you'll find a live countdown till Impact here: https://saturn.jpl.nasa.gov/mission/sat ... ssini-now/
Current velocity is about 31.000 mph and rising rapidly. Distance 193.000 miles. Only a few hours left.

Personally, I'd have preferred the probe to be left alife, perform a swing-by and be flung out further into the system, like they did with others.
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Re: Science Tidbits #5

Postby Lupine » Fri Sep 15, 2017 3:05 pm

^I'm not sure it has enough fuel to do that. In any rate they wanted to be sure that it didn't bring any biological contamination to Enceladus or Titan.
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Re: Science Tidbits #5

Postby RJDiogenes » Fri Sep 15, 2017 9:53 pm

^^ Which I always found a little odd, since they landed something right on Titan. Huygens gets to retire comfortably by a methane lake and poor Cassini gets torched.

RIP, Cassini. :bye:

Actually, what I thought would have been cool would be to swing Cassini around and slingshot him back to Earth. In about ten years, we could send up something to grab him and then we could build a museum around him.
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Re: Science Tidbits #5

Postby Lupine » Fri Sep 15, 2017 10:07 pm

^That would be cool. We've never retrieved anything from that far out before. Perhaps they could have even flown it through one of Enceladus's geysers on the way and see if any residue could make the trip.
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Re: Science Tidbits #5

Postby huggle » Sat Sep 16, 2017 4:37 am

great idea! Only, if there was no fuel left how would we have slowed the probe down once it arrived here? The slingshot maneuvre would have given it an incredibly speed so that our gravity field wouldn't have been able to catch it. Last time I looked the speed was around 300 miles per second.
Btw, Nasa cheated a bit: when I last looked at 11:15 pm CET the countdown claimed it was still a little under 100,000 miles from Saturn. But by 11:45 CET they claimed it had been destroyed at 10:31 CET. But I guess the 80+ minutes runtime of the signal from Saturn to Terra would account for it.
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Re: Science Tidbits #5

Postby Lupine » Sat Sep 16, 2017 3:08 pm

huggle wrote:Only, if there was no fuel left how would we have slowed the probe down once it arrived here? The slingshot maneuvre would have given it an incredibly speed so that our gravity field wouldn't have been able to catch it. Last time I looked the speed was around 300 miles per second.

Perhaps aerobraking. Though that would present problems as well.
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Re: Science Tidbits #5

Postby RJDiogenes » Sat Sep 16, 2017 7:33 pm

I didn't even think about the speed, I just figured a custom probe could grab it. But rendezvous and docking would take a ton of fuel. They'd probably have to do some complicated gravity-assist braking, like swing it around Venus and then back up to Earth or something. Or a slow loop back around the sun, although that would probably triple the travel time.

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Re: Science Tidbits #5

Postby Orpheus » Mon Sep 18, 2017 4:58 am

Look, if you want to say our climate is changing, I'd go along with that -- but I wouldn't call it anywhere near conclusive because climate works on a planetary timescale, in which all of human civilization is too small to judge.

If you want to say our climate WILL change, I'd call that a certainty. Humanity is an ice creature, that has only existed during an ice age that's lasted (depending on which climate change you call "Ice Age") 5-35 million years. To be more specific, everything we *actually* know of humanity doesn't even go back to the beginning of the last glacial recession -- out of many advances/retreats In the past few million years.

If you're going to say "reduce carbon emissions" --- I'll say "go for it". I'm all for living lightly on Mother Earth. And it's great training for life on other planets

If you're going to pose anything resembling global warming, including heat-driven mega hurricanes, massive coastal flooding, etc. I'd laugh -- it'll happen "for a minute" on the planetary timescale, but the planet has been trending massively cooler all through its history.

Here's the past 5 million years (using 18O/16O isotope ratios to estimate temperature).
Note where we are NOW temperature-wise, relative to just that short geological span.
Look at the size of the swings, before Lucy thought to walk on her hind legs.

Five_Myr_Climate_Change.png
Five_Myr_Climate_Change.png (18.34 KiB) Viewed 488 times


Now let's zoom back about a factor of ten to 65 Myr. Again, note where we are NOW temperature-wise:

65_Myr_Climate_Change.png
65_Myr_Climate_Change.png (20.99 KiB) Viewed 488 times


Let's zoom back roughly another factor of ten to 542 Myr. Again, note where we are NOW temperature-wise.
Note the bars at the bottom denoting various ice ages (periods when year-round polar ice existed). As you can see, that's not normal for our planet. It's just *seems* normal to us pipsqueak Johnny-come-lately infants.


Phanerozoic_Climate_Change.png
Phanerozoic_Climate_Change.png (30.3 KiB) Viewed 488 times


The real Inconvenient Truth is that we are not the Masters of the Earth, capable of ruining it with a foolish error.
The real Inconvenient Truth is that we can make things bad for ourselves, and the species around us, but we must bow to Mother Nature still. We can't save NOLA -- probably not even NYC. We put them in places that were convenient for the moment, as we have with all our cities even before Mohenjo-Daro and Harrappa. Like every ancient city, when the climate shifts, even temporarily --even for a century or two-- they're toast. We are not-so-humble bugs, as always.
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Re: Science Tidbits #5

Postby huggle » Mon Sep 18, 2017 1:03 pm

I partially agree. There have always been climatical changes in the past, some of them greater than the current one.
However, the speed of the current change is something as yet unheard of and that's what causes major problems for many species. They can't adapt that quickly. And if one species dies out, all those species who are dependent on it will suffer the same fate.
I am not sure if I can explain these complicated species relations properly in English so I'd like to use a simile. Purely fictional but it could happen any day now:

People on a remote tropical island extinguished a little beetle that apparently had no use whatsoever and wasn't even pretty but actually rather ugly. Two years later a war broke out.
The beetle was the favourite food of a species of bird that used to fly out over the sea and leave their droppings there. Tiny fish used to feed on these droppings and were caught by the inhabitants of the neighbouring island and used as fertilizer. Since there was no fertilizer anymore, the islanders were starving to death and attacked their neighbours in the hope of conquering fertile soil.

As I said, purely fictional but it could happen tomorrow. It's a perfect example of how species are connected - most of the time unbeknownst to us - and how our lack of knowledge can trigger an avalanche of events we'd never have expected. An ecosystem is an equation with literally millions of unknown factors. It's impossible to predict in detail. But we can predict with certainty that a change in any factor will have consequences, some of them possibly lethal.

If a change comes slowly, nature will adapt. For example, the falling sea levels forced fish to develop lungs and legs. However, if the water levels fall fast, the fish will simply die and mummify. What worries us biologists so much is not the climatical change in itself but its extraordinary speed. Change must not be faster than evolution, else species will die out. The ecosystem will literally get holes and these holes will be like ladders/runs in a nylon stocking: impossible to mend. Contrary to hosiery, we have no drawer full of spare earths.
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Re: Science Tidbits #5

Postby Lupine » Mon Sep 18, 2017 3:17 pm

Orpheus@cwm wrote:The real Inconvenient Truth is that we are not the Masters of the Earth, capable of ruining it with a foolish error.

Yes we can. Merely stating that the climate has always changed is a bit of a strawman argument since no one has ever suggested that the climate has stayed stagnant for the last 4 billion years. There are over 7 billion of us and that number is growing and we're realizing massive amounts of carbon in the air and that has to have some effect. Yes, life can adapt. Yes, we can adapt. But, to put it roughly, that's like saying that we shouldn't avoid car wrecks because there are always other cars.
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Re: Science Tidbits #5

Postby RJDiogenes » Mon Sep 18, 2017 9:51 pm

Orpheus@cwm wrote:If you're going to pose anything resembling global warming, including heat-driven mega hurricanes, massive coastal flooding, etc. I'd laugh -- it'll happen "for a minute" on the planetary timescale, but the planet has been trending massively cooler all through its history.

The problem is that "for a minute on the planetary timescale" is enough to wipe out human civilization. I'm sure we don't have the ability to ruin the planet in the long term-- the biosphere could probably even recover from all-out nuclear war-- but that's cold comfort if everything we've ever created or have the potential to create is wiped from history. Remember that "Buddy Holly" speech from Babylon 5?

We can't save NOLA -- probably not even NYC. We put them in places that were convenient for the moment, as we have with all our cities even before Mohenjo-Daro and Harrappa. Like every ancient city, when the climate shifts, even temporarily --even for a century or two-- they're toast. We are not-so-humble bugs, as always.

If we can't save NOLA and NYC (and Boston), then we are indeed in big trouble-- rising sea levels will not only wipe out the centers of civilization, but decrease the available land for an already overcrowded planet. People go to war over resources.
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Re: Science Tidbits #5

Postby Orpheus » Mon Sep 18, 2017 11:45 pm

I fully agree that it puts humans at risk. I don't believe that it endangers us as a species. I don't see any evidence to justify that at all.

Yes, Boston is at risk. I only mention NOLA and NYC because they had recent hurricanes that illustrated it.

I feel obligated to repeat that:
1) I
personally believe in climate change (but I don't call that opinion "science": Science sometimes demands more evidence than we have or can get in time)
2) I personally believe in reducing emissions/pollution (as a general policy, even if climate change weren't an issue)
3) I personally believe that we must put our efforts to adapting and adjusting (vs some vague delusion of "stopping" or "reversing" the change.
4) I personally believe that our hubris in seeing ourselves as the major cause AND capable of reversing the change is steering us away from the necessary policies

Even if we "caused" climate change, it doesn't mean we can "stop it". A look at the interglaciation cycle shows that the Earth was about due to "come to a cliff" anyway, and just because you push something off a cliff doesn't mean you have any power to stop its fall. Even making the attempt (and yes, there are geo-engineering projects underway) would simply be Deliberately committing the hubris that geo-engineering proponents claim we committed accidentally. Like it or not, short-term (1 century) tests would not give the data we need to determine the effects of, e.g., underground CO2 sequestration (like fracking, except we don't extract anything), seeding the Humboldt current with iron (increases plankton CO@ sequestration), and other measures underway. If we don't have multiple (sequential, refined) experimental series before we start "messing with things" --with the INTENT of making substantial changes!-- well, that's not science at all. We can't restore a balance that we very simply DO NOT understand. Creating a balance requires exquisite knowledge and control, not brute force.

Even if ALL climate change were anthropogenic and humanity disappeared tomorrow, Earth's climate would continue its anthropogenic changes for 1000 years or more. You don't have to take my word for it. The current (Fifth) Assessment Report (AR5, 2013) of the Intergovernmental Panel on Climate Change (IPCC, the international authority] reports in Chapter 12 ("Long-term Climate Change: Projections, Commitments and Irreversibility"):

Some aspects of climate will continue to change even if temperatures are stabilized.
Processes related to vegetation change, changes in the ice sheets, deep ocean warming and
associated sea level rise and potential feedbacks linking for example ocean and the ice sheets
have their own intrinsic long time scales and may result in significant changes hundreds to
thousands of years after global temperature is stabilized. {12.5.2 to 12.5.4}


Incidentally: do you notice that the 18O curve is much more jagged in recent times (even long before H sapiens)? That's because diffusion makes it impossible to see sharp changes, unless they are recent -- the further back you go, the fuzzier the picture is. It is simply bad science to say that we are experiencing "unprecedented" rates of change. We don't know the per-decade (or per-century) rates during ANY glacial cycle, not even the current one. Also, when we ourselves climate-model the shifts between relatively stable local equilibria (e.g. eras of glacial advance and retreat) we see decades-long swings in BOTH directions before it settles down to the new state.

Humans aren't great at science. We haven't been doing it very long. Some of you may know of my long rants about Scientific Medicine being under a century old (as I used to say in the 70s/80s) and hence a primitive Science, and how even today Evidence-Based Medicine is still broadly resisted in practice -- more than you can ever imagine! (Heck, I can think of dozens of common rules/principles I was taught, then told in the next sentence "but studies don't bear that out")

I've devoted my life to science/technology, but I don't kid myself: future generations will think we were "quaint" at best, "wrong-headed" at worst. We still need to keep working at it.
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Re: Science Tidbits #5

Postby RJDiogenes » Tue Sep 19, 2017 9:38 pm

Orpheus@cwm wrote:I fully agree that it puts humans at risk. I don't believe that it endangers us as a species. I don't see any evidence to justify that at all.

I don't think we're at risk as a species, just as a civilized species. I can easily see us reverting to Medievalism, if not Stone Age barbarism.

Yes, Boston is at risk. I only mention NOLA and NYC because they had recent hurricanes that illustrated it.

Boston must be our top priority!

3) I personally believe that we must put our efforts to adapting and adjusting (vs some vague delusion of "stopping" or "reversing" the change.

We should ideally be doing both, because even a full-scale effort to reverse the effects of climate change will take many decades-- if successful.

4) I personally believe that our hubris in seeing ourselves as the major cause AND capable of reversing the change is steering us away from the necessary policies

I love hubris. Hubris is one of my favorite things. Hubris is what makes humanity great. :D

I've devoted my life to science/technology, but I don't kid myself: future generations will think we were "quaint" at best, "wrong-headed" at worst.

I think that already. :lol:
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Re: Science Tidbits #5

Postby huggle » Wed Oct 18, 2017 11:12 am

Just found this rather crazy bit of science news https://www.swr.de/natuerlich/erstaunli ... index.html
Falling foliage makes planet rotate faster
In fall, when the trees drop their foliage, Earth reacts like a figure scater doing a pirouette: if he pulls in his arms towards his chest, he rotates faster. Physicists call it 'conservation of the angular momentum'. When the foliage is no longer attached to the trees but lies on the ground it's closer to Earth's axis. The effect is not noticeable but measurable: in winter, earth rotates 1/1000 sec faster than in summer.

IMHO that theory overlooks one vital fact: when it's fall here, it's spring on the southern hemisphere. That would either result in both Forces eliminating each other or it should slow the southern half of the planet down. If so, the planet ought to get twisted. That'd result in geographical shifts of landmarks which so far nobody has detected. The same effect would take place in areas where it's night and people lie down, thus bringing their mass closer to the planetary axis. No sign of any nighthly distortions have been recorded afaik. Hence I see no evidence in favour of the leaf theory (it's sorta cute, though).
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Re: Science Tidbits #5

Postby Lupine » Wed Oct 18, 2017 2:56 pm

Yeah, that actually makes no sense whatsoever- especially for the reasons you point out.
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