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If Earth Never Had Life, Continents Would Be Smaller
sciencehabit writes It may seem counterintuitive, but life on Earth, even with all the messy erosion it creates, keeps continents growing. Presenting here this week at the annual meeting of the European Geosciences Union, researchers say it's the erosion itself that makes the difference in continental size. Plant life, for example, can root its way through rock, breaking rocks into sediment. The sediments, like milk-dunked cookies, carry liquid water in their pores, which allows more water to be recycled back into Earth's mantle. If not enough water is present in the mantle about 100 to 200 km deep to keep things flowing, continental production decreases. The authors built a planetary evolution model to show how these processes relate and found that if continental weathering and erosion rates decreased, at first the continents would remain large. But over time, if life never evolved on Earth, not enough water would make its way to the mantle to help produce more continental crust, and whatever continents there were would then shrink. Now, continents cover 40% of the planet. Without life, that coverage would shrink to 30%. In a more extreme case, if life never existed, the continents might only cover 10% of Earth.
Then what about all the plants preventing erosion?
I wonder what implications this has for alien worlds that somehow ended up vaguely earthlike, with lots of liquid water, yet never developed life despite being generally hospitable. Offhand I think it's certainly possible that such worlds exist, but this would seem to indicate that they'd more likely be predominantly oceanic, with only small continents or isolated archipelagos for land mass.
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If the sun were ten times hotter, there wouldn't be life on Earth.
If humans needed to breathe in methane instead of oxygen, there wouldn't be humans on Earth.
See, I can play the game as well....
It may seem counterintuitive, but life on Earth, even with all the messy erosion it creates, keeps continents growing.
It had never occurred to me to consider that life might cause erosion. That's usually what wind, rain, and gravity are famous for, isn't it? Plant life is pretty famous, surely, for countering erosion by stopping soil getting washed away (a lack of which leading to occasionally disastrous consequences in flash floods, for example).
The sediments, like milk-dunked cookies, carry liquid water in their pores
Milk-dunked cookies don't carry liquid water in their pores. They carry milk. So the sediments are more like water-dunked cookies, moreso because they both taste yucky.
But over time, if life never evolved on Earth, not enough water would make its way to the mantle to help produce more continental crust, and whatever continents there were would then shrink.
Now, continents cover 40% of the planet. Without life, that coverage would shrink to 30%. In a more extreme case, if life never existed, the continents might only cover 10% of Earth.
That's very confusingly written. The first sentence say "if life never evolved on Earth...continents there would then shrink." But then how did those continents get so big in the first place? Surely shrinking continents is only the case when life did evolve, but then theoretically all dies off.
systemd is Roko's Basilisk.
Seems like this could have drastic effects on how we search for life. Not only are we looking for planets in the Goldilocks zone, but we now know that if we see too much water it could be a sign that there an absence of life.
Troll is not a replacement for I disagree.
If a planet has liquid water on it it's just a matter of when life exist not if.
Personally I think a lot of cellular level life is out there blowing around like dandelions, they drop in and adapt.
"If any question why we died, Tell them because our fathers lied."
It seems to me a lot of solid earth surface is produced by bringing up stuff from below. IIRC, aren't the Hawaiian, islands though not continents, the result of volcanic activity? The interactions along the earth's tectonic plates could uplift surfaces, too. Not an earth scientist, so not sure.
In a time of universal deceit, telling the truth is a revolutionary act. George Orwell
a more accurate pedantic analogy from you would be:
"if there were no people, then God or some other deity could enjoy smaller more petite yet ultimately pointless continents"
, and you would still lose
Will there still be seven of them, and will this appear in our Finals?
Continents ignore exit statuses like systemd does. There. Brought us back on topic.
Would not have been created, either. Bam!
Obviously: Since without Life our oceans would be larger, it doesn't take a genius to see that life is negatively impacting the size of our oceans.
As a conservationist I am deeply concerned about this.
Also, by the same token -- it disturbs me that all this out-of-control biology has clearly had an effect on the chemical composition of our atmosphere. Why is no one more freaked out by this? Historic records clearly show that our atmosphere has become tainted with oxygen as a result of all this "life".
Are you okay with chemical changes to the atmosphere, and smaller oceans? Well? Are you?!
------ The best brain training is now totally free : )
Same people that probably say man made global warming too.
Am I the only one who thought this was going to talk about how we're all living on a big continent of dead bodies and poo..
I guessing there must but a segment of the Geosciences academia are all playing a joke on us to simply prove we are all standing on piles of all of life's shit.
The joke is even better because someone in academia is going to get their Doctorate and full tenure and never have to work a day in their life again.
Tracy Johnson
Old fashioned text games hosted below:
http://empire.openmpe.com/
BT
So living things will eventually lead to Flat Earth due to erosion. Maybe I should have said flat earth, as in soil under your feet.
-Eric