Sierra-117-

Sierra-117- OP t1_j6226fl wrote

Well bears don’t automatically go for the kill. In fact, I just saw a story on Reddit about a man that encountered a grizzly and fought it off, because it was only gnawing on his thigh. He eventually got it to go away by stabbing it with a pocket knife.

I’m just saying it may not have been 100% going for the kill, but it was definitely trying to get a meal. Just the fact that it didn’t run away at a sign of resistance shows that. Polar bears don’t “play”

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Sierra-117- OP t1_j61iqzv wrote

I don’t think so. Polar bears aren’t really docile creatures. All other bears look calm and peaceful compared to them. There’s not a lot of food in the arctic, so they eat practically anything that moves

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Sierra-117- t1_j25bpxn wrote

My girlfriend has a very toxic family. She had to raise her own brothers. I constantly have to remind her of this. The battle is over, it’s time to rest and focus on yourself. If you don’t do it now, you’ll always put their needs before your own. Get stable first, then you can worry about helping others

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Sierra-117- t1_iua713a wrote

“Previous attempts to make tetrataenite in the laboratory have relied on impractical, extreme methods. But the addition of a common element – phosphorus – could mean that it’s possible to make tetrataenite artificially and at scale, without any specialised treatment or expensive techniques.”

“The researchers say that phosphorus, which is present in meteorites, allows the iron and nickel atoms to move faster, enabling them to form the necessary ordered stacking without waiting for millions of years. By mixing iron, nickel and phosphorus in the right quantities, they were able to speed up tetrataenite formation by between 11 and 15 orders of magnitude, such that it forms over a few seconds in simple casting.

‘What was so astonishing was that no special treatment was needed: we just melted the alloy, poured it into a mould, and we had tetrataenite,” said Greer. “The previous view in the field was that you couldn’t get tetrataenite unless you did something extreme, because otherwise, you’d have to wait millions of years for it to form. This result represents a total change in how we think about this material.’”

This is… actually quite promising. Usually in r/science there’s a massive caveat. But if there is one here, it’s not obvious. A reaction done with abundant materials at achievable temperatures and timescales. Without specialized equipment.

If tetrataenite truly can be used to replace rare earth metals in some applications, this is a massive discovery.

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Sierra-117- t1_iu1dxy8 wrote

Also I realize my comment was confusing. I’m not saying it has a completely cool core, we’re a long way off from that. But it’s core is relatively cool, and therefore volcanic activity has pretty much ceased.

But the crust of a rocky planet gets most of its energy from the star it orbits

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Sierra-117- t1_iu1cvzm wrote

Well it takes a lot more energy to melt metals into liquid than rock.

Metal also has a higher rate of energy transfer. So the metal cools faster, and takes far more energy to stay hot.

The core is also more stable than the mantle, meaning is experiences less friction and therefore produces less excess heat.

The heat from the core will constantly radiate into the mantle, so the mantle is constantly gaining energy while the core cools. Because the core is HOT, just not hotter than we would expect under the given pressure.

Lots of factors, and there’s a lot more I could list! But basically it comes down to: the core has now cooled to a stable temperature, therefore the mantle has cooled to a stable temperature, therefore volcanic activity is likely to cease.

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Sierra-117- t1_iu1bhya wrote

Yes! It is still very hot, like the core of any planet. Gas giants have cores hotter than the surface of the sun.

But when you say “hot core” in planetary science, it means a REALLY hot core. As in, hotter than it should be given the pressures involved.

This excess heat usually comes from conditions experienced during formation. Earth’s core is a hot core, because we currently believe a small planet collided with the early Earth! (Though this is also still only theory).

But yes, the interior of mars is very hot. Just not hot enough to support continued volcanic activity in the mantle/crust.

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Sierra-117- t1_iu1anpm wrote

Well you misunderstand what produces volcanos.

The core helps KEEP a planet warm, and keep lava flowing. But the lava itself is created and flows from the mantle, not the core. So some believe that Mars has a relatively cool core, but it’s mantle was still hot after formation.

Basically, a cool core with a short time of volcanic activity after formation due to heat trapped in the mantle.

Which is why we don’t see volcanic activity on mars today, but we see evidence of it in the past. The mantle is now cooled.

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Sierra-117- t1_iu19cto wrote

Very good question!

It was able to maintain liquid water through a thicker atmosphere than it currently has. Basically, a greenhouse effect. It would still be freezing at night though.

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Sierra-117- t1_iu0yv16 wrote

No, because we aren’t sure if Mars ever had a hot core. Right now, it’s not hot enough to create geothermal activity. So if an ocean existed on mars today, life would not form via geothermal activity. But maybe in the far flung past, who knows?

Also, geothermal activity isn’t the only theory of abiogenesis. I’m quite fond of the clay hypothesis. Where molecules being wetted and dried continuously in the presence of silica crystals (like on the bank of a river) will form complex self assembling structures.

Edit: just to clear up some things. Yes, mars core is hot. But it’s much cooler relative to earth. But I’ve just learned that new research thinks mars may still be volcanically active! Just far more dormant than a planet with a very hot core and mantle like earth. Earth likely experienced a massive event (giant impact hypothesis) that gave it a lot of excess energy, which means a lot more active volcanoes. Perfect for life!

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