Submitted by tripperfunster t3_zyslds in askscience
r2k-in-the-vortex t1_j2896qx wrote
Very little. It depends of course on local geology, but is generally well below 1W/m2 compared to sunlight being 1000W/m2
You can of course see the effect on poles, there is magma under Antarctica just the same, but it's still covered with couple km thick ice.
So in terms of temperature it makes no difference directly. But indirectly tectonic activity makes a very large difference. With a solid core we wouldn't have mountains left, it would have all eroded flat over billions of years. Without volcanic emissions we wouldn't have enough carbon for lush foliage, because it has a tendency to form sediments. Earth would be an iceball without enough CO2 to keep the heat in.
_AlreadyTaken_ t1_j29iibw wrote
It is impressive how little heat escapes, mainly due to the extremely slow convection in the earth. This is a good thing because it has kept the iron core fluid for billions of years and a magnetosphere that protects against loss of hydrogen and water in the process.
theCumCatcher t1_j2c36bd wrote
this is something i feel is missing from the explaination.
without our magnetic field, genetic life couldnt exist in the radiation produced by our star.... and even our atmosphere woule be eroded away by solar wind
​
there is a HUGE difference between a 'dead' core and 'active' core world.
one has an atmosphere, magneticfield, and life.
the other, all things being equal, does not
_AlreadyTaken_ t1_j2cdktk wrote
We wouldn't lose our atmosphere, Venus barely has a magnetic field and it has a very thick one. It helps us hold onto lighter elements. Water vapor could be photodissociated into oxygen and hydrogen and the hydrogen stripped away. We could also lose the ozone layer. There is even a weak spot in the magnetic field, the South Atlantic Anomaly.
You don't absolutely need it but it definitely helps.
theCumCatcher t1_j2ew7u5 wrote
this is true. I worded my answer poorly.
the sun would irradiate anything alive on the surface while high energy particles whittled away at the ozone, making it worse.
​
NOT TO MENTION, you are absolutely right with venus. it has gravty on its side, there
if we had a weaker pull, like mars, then in that case i think it would erode the atmosphere completely
I'll direct you to look at the MAVEN discoveries, to verify me there
_AlreadyTaken_ t1_j2fmtd4 wrote
I'll toss out one more thing to think about. Life clearly evolved on earth before there was any ozone layer and ultraviolet light was bombarding the surface because it appeared before photosynthesis did so there was no free oxygen (or very very little) in the atmosphere to make ozone. So life can develop in spite of UV light, probably in water too deep for UV light to penetrate. Did photosynthesis evolve from mechanisms to protect against UV light in shallow water? Who knows...
theCumCatcher t1_j2fnzk5 wrote
about the origin of photosynthesis.
I think there is something there.
if we look at the visible spectra of the sun,
https://www.sunlightinside.com/wp-content/uploads/2017/09/Sunlight_spectrum_Fiji_July.jpg
green and red are its largest components.
the protective pigments in leaves that reflect this red light (carotenoids) become visible when the chlorophil dies in the fall.
suspiciously, chlorophil reflects the remaining green part of the spectra almost perfectly
it could be the chlorophylls evolved from one of these pigments.
thats really neat
_AlreadyTaken_ t1_j2fp8nf wrote
I even read that purple bacteria appear to be older than chlorophyll photosynthesis. So either absorbing green, the peak of the solar spectrum is TOO much energy (heat can disable the enzymes) or that part of the spectrum was already filled by organisms so the green ones took what was left.
Chlorophyll is also composed of many subunits that likely have been added as enhancing features over time, like energy transmitting antennae structures that funnel the photon energy to the reaction center.
I used to date a woman who was researching the dna structure of photosynthetic bacteria. :D
[deleted] t1_j2fu56b wrote
[removed]
OlympusMons94 t1_j29lrit wrote
Tectonic and volcanic activity are caused by processes in the crust and mantle. Though the mantle very slowly flows and deforms like tar or putty, it is overwhelmingly solid (albeit very hot) rock. Magma exists only in certain regions of the crust and mantle, and even then mostly as a partial melt in a solid matrix, like water in a sponge, or slush.
The core does provide some heat from below, which helps power that activity, in addition to the heat in the mantle leftover form Earth's formation, and the heat in the mantle and crust generated by radioactive decay. But the core is not directly involved, and it being solid or liquid (it is both, actually, with a solid inner core and molten outer core) wouldn't necessarily preclude or permit volcanic or tectonic activity.
mycatpeesinmyshower t1_j2bo11r wrote
Also without magma moving iron around we wouldn’t have a magnetic flow and we’d be like Mars and lose all our atmosphere right?
starlevel01 t1_j2cfzkj wrote
If the magnetic field turned off tomorrow, it would take many millions of years for the solar wind to strip our atmosphere away. The biosphere replenishes lost gases very quickly as well, and whilst that wouldn't really like the extra solar radiation it would eventually adapt.
mycatpeesinmyshower t1_j2cgpsh wrote
Well if we didn’t have it in the past we likely wouldn’t be here today.
BluScr33n t1_j2doxc7 wrote
No, Earth is way more massive than Mars and won't lose its atmosphere as easily. The upper layer of the atmosphere is ionized by solar radiation. Instead of simply stripping our atmosphere away, the solar wind would induce a magnetic field in this upper ionosphere. And this induced magnetic field would exactly cancel the magnetic field from the solar wind, ultimately deflecting the solar wind around Earth. This is exactly what happened on Venus and is one of the reasons why Venus still has an atmosphere.
The same thing also happens on Mars, but because Mars is significantly less massive it still lost most of its atmosphere over time from various processes.
But you are correct with your idea that Earth would lose its intrinsic magnetic field if the core cooled down and solidified.
kyler000 t1_j2bw3sk wrote
Do you have more info on how volcanic carbon emissions affect foliage? It seems like there would still be plenty of carbon to go around and that volcanos just contribute more to the carbon cycle. Or is it part of the cycle? Like some carbon is sequestered due to tectonic activity and then released by volcanos?
r2k-in-the-vortex t1_j2d5wix wrote
Carbon is sequestered because sedimentary rocks form which contain a lot of carbon, without volcanic emissions to offset that, atmosphere would slowly(over millions of years) run low on carbon. That has happened in geologic history resulting in several periods of snowball Earth, sea ice all the way to equator. To break out of this state enough volcanic activity had to happen for CO2 concentrations in atmosphere to build up again.
theCumCatcher t1_j2c2xs3 wrote
I wonder why you didnt mention a heat generating core vs a 'dead' core in terms of the magnetic field, the atmosphere, and the star we orbit around
Viewing a single comment thread. View all comments