7 ms·

Cosmic rays streamed through Earth's atmosphere 41k years ago

89 points by wglb 3y ago

ClassyJacket 3y ago
Cosmic rays: interfering with Mario 64 speedruns since 38,976 BC
dveeden2 3y ago
I misread the title as "Comic rays..."
- skhr0680 3y ago
  It's how that font came to Earth
  - danparsonson 3y ago
    Ah, the old 'Pankernia' theory. I'll see myself out.
defrost 3y ago
Variations in cosmogenic radionuclides like beryllium-10 provide an independent proxy of how Earth's paleomagnetic intensity changed. Indeed, Panovska found that the average production rate of beryllium-10 during the Laschamps excursion was two times higher than present-day production, implying very low magnetic field intensity and lots of cosmic rays reaching Earth's atmosphere. Specifically, I'd guess, that twice as many cosmic rays reached the surface, at that location, than the mean present day average that reach the surface. * The location hedging is due to: magnetic field excursions, brief periods in which the intensity of the magnetic field wanes and the dipole (or two magnetic poles) that we're familiar with can disappear, replaced with multiple magnetic poles. The Laschamps excursion that occurred around 41,000 years ago is among the best studied. It features a low magnetic field intensity that implies less protection for Earth's surface from harmful space rays. So the magnetic sheilding in the upper atmosphere and further out "in space" had 'holes' and was not like the 'modern' IGRF. The Earth still had a denser lower atmosphere, though, which also provides protection from cosmic rays - geophysical air surveys for ground radiometrics have to calibrate for cosmic rays by running "stacks" .. survey lines high up in the air and prgressivel closer to the ground in order to estimate the cosmic falloff with atmospheric density for the duration of the ground survey. * "twice as many* is also a hand wave, cosmic ray energy has a spectrum and the changed geomag field would bend the pass through spectrum and likely allowed more high energy gamma's through .. the end result was the doubling of the creation of a proxy indicator.
- littlestymaar 3y ago
  > cosmic ray energy has a spectrum and the changed geomag field would bend the pass through spectrum and likely allowed more high energy gamma's through The earth magnetic field has no shielding effect on gamma rays at all (which are photons), only on charged particles (protons, electrons and their heavier variants: muons and hypothetically tau leptons but IDK if there are any of them in cosmic rays)
  - defrost 3y ago
    The earths magnetic field traps charged particles (mostly protons and electrons) from the solar winds into large donut-shaped belts around the Earth, well outside of the extent of the atmosphere. It's these particle belts which filter cosmic rays (gamma radiation) and as the magnetic field fluctuates so too does the spectrum of high energy gamma radiation that makes it through the charged particle shielding, which is further filtered by the atmosphere. You're correct that there's no direct magnetic transformation of the incoming gamma spectrum, I was casually referencing the very real indirect effect.
    - littlestymaar 3y ago
      It's the first time I ever hear about such an effect and I admit I have a hard time believing it since the particle density is very low in the Van Allen belt. Do you have any source for that? (Google couldn't help)
      - defrost 3y ago
        The inner Van Allen donut is some 8,000 km thick (from ~1,000km above ground surface stretching out to ~8,500 km or so) and denser than the much much larger outer donut that (IIRC) stretches from 3 earth radii to 10 earth radii. Low density but a lot of particles, many with high energy, sourced mostly from solar ejection, with cosmic particle and cosmic gamma strikes on the upper atmosphere sourcing a significant chunk of additional charged particles for the inner belt, and both receiving decay particles from cosmic high energy gamma and cosmic charged particles strikes on particles already within the belts (at a proportionatly lower rate than those from upper atmosphere interaction). It's a Pachinko game, the density is low but the strikes do happen. The effect I refer to is studied on again | off again (eg: iirc, Robert Forward looked at "draining the Van Allen belts" to remove charged particles and there were papers looking at the sheilding factor for cosmic that would be lost) but largely tossed in as an "and also" .. eg: https://science.nasa.gov/science-research/earth-science/earths-magnetosphere-protecting-our-planet-from-harmful-space-energy/ https://science.nasa.gov/science-research/earth-science/eart... our magnetosphere shields us from erosion of our atmosphere by the solar wind (charged particles our Sun continually spews at us), erosion and particle radiation from coronal mass ejections (massive clouds of energetic and magnetized solar plasma and radiation), and cosmic rays from deep space. Most of the focus tends to be on the cosmic charged particles with mass rather than the massless photons. I admit I've largely only concerned myself with the fall off of the gamma spectrum through the atmosphere, but I've had past discussions with some on the fall off of the (cosmic) gamma spectrum as it approaches Earth and figure there must be papers on this about. The Chandra X-ray Observatory calibration procedure papers would likely be our best bet for a good source, the satellite has an eccentric obit ( Perigee altitude 14,307.9 km, Apogee altitude 134,527.6 km ) which puts it fully outside the denser high energy inner belt but half in | half out the less dense outer belt. There would have to be a procedure to factor out the variation in "local" X-Ray events as it moves about the planet in order to sharpen the data from the two Grating Spectrometers
mfritsche 3y ago
https://en.m.wikipedia.org/wiki/The_Seven_Daughters_of_Eve https://en.m.wikipedia.org/wiki/The_Seven_Daughters_of_Eve a few of the seven mothers of Eve seem to have lived around the same time. Just an observation.
- defrost 3y ago
  Interesting book, very hard to tell whether you're a serious twue believer or just engaged in some wry leg pulling: Howy Jacobs in Nature labelled the book as semi-fictional with the majority of the information "the accounts of the imagined lives" of human ancestors. He commented: "All this made me feel that I was reading someone's school project, with influences from The Flintstones cartoon series, rather than a treatise by a leading academic." The wikipedia summary didn't give a time frame for the book events, however the Laschamp event was 42 thousand years before prest .. after the settling of coastal and much of inland Asia, Australia, etc. It seems a little near in time for a literal bottleneck of seven women's genetics, I feel even Bryan Sykes would have pushed back his dating of the seven clan mothers further than a mere 42 kyears. https://en.wikipedia.org/wiki/Laschamp_event https://en.wikipedia.org/wiki/Laschamp_event
  - rsync 3y ago
    "It seems a little near in time for a literal bottleneck of seven women's genetics ..." The bottleneck was figurative. No actual bottle was involved. (I have five figures of karma with which to fight this battle).
    - o11c 3y ago
      A lot of people misunderstand figurative bottlenecks too. The "7 women" does not mean anything like "only 7 women existed at the time". Particularly: * other women existed who only had sons, or whose daughters only had sons, etc. See https://en.wikipedia.org/wiki/Galton%E2%80%93Watson_process https://en.wikipedia.org/wiki/Galton%E2%80%93Watson_process (about surname extinction, which is basically the same thing other than sex-specific polygamy effects) * other tribes existed (or split off) who later faced extinction due to being outcompeted by these 7 tribes.
euroderf 3y ago
In the 60s I read a (crackpot?) theory that the Old Testament was not kidding when it says people lived hundreds of years, and that a sudden influx of cosmic rays could explain a nexus of Biblical events - the dispersion of a persistent global cloud cover that had existed until then, the rain & flooding event that Noah rode out, and the subsequent reduction (thanks for nothin', cosmic rays) in human lifetimes.
- xattt 3y ago
  If anything, cosmic rays would (stochastically) seed clouds. Constant cloudiness would suggest that Earth was under bombardment at that time. (1) https://www.science.org/doi/10.1126/science.1076964 https://www.science.org/doi/10.1126/science.1076964
- i67vw3 3y ago
  Fun thing about the Noah 'story' is that the exact same story is present in Hinduism. It goes something like, God selected a righteous person to help humanity survive the flood. He has this individual built a big ship in which humanity and animals can survive. The only difference in the story is that God took a form of small fish which grew larger as the flood date came close. In the end it became so big that it was able to steer the big ship during flood waves. https://en.m.wikipedia.org/wiki/Matsya https://en.m.wikipedia.org/wiki/Matsya
  - Tuna-Fish 3y ago
    The story in the Vedas probably has the same origin as the Mesopotamian flood myths. The oldest surviving Akkadian and Sumerian references to the flood precede and are pretty close in time to the Aryan expansion to the Indian subcontinent, and the Mesopotamian cities had long-lasting trade, cultural and military links to the peoples living in the Iranian plateau. I love speculating on the origin of the flood myths. My personal favorites are long-lasting oral traditions about the Black Sea flood and the Persian Gulf flood, both of which were rapid, catastrophic large-scale floods of large areas that were previously settled by humans. Sadly, the true origin is probably a lot more banal -- the oldest surviving fragmentary literary evidence refers to the specific city that flooded, Shuruppak, or modern Tell Fara. There is indeed a significant flood layer there (60cm of alluvial sand!) at about the right time (2900BC), but this was left by a normal river avulsion that created a violent but local flood.
stanac 3y ago
> periods in which the intensity of the magnetic field wanes and the dipole (or two magnetic poles) that we're familiar with can disappear, replaced with multiple magnetic poles If this was a basis of a movie plot I would think how stupid the movie is. Apparently it was normal for earth to have more than two magnetic poles before earth core started to solidify [0]. Was earth core composed of multiple elements where each had two magnetic poles? Also somewhat relevant wiki articles: Geomagnetic excursion [1], Laschamp event [2] and Geomagnetic reversal [3]. [0] https://www.popularmechanics.com/science/environment/a21528/ancient-earth-magnetic-field/ https://www.popularmechanics.com/science/environment/a21528/... [1] https://en.wikipedia.org/wiki/Geomagnetic_excursion https://en.wikipedia.org/wiki/Geomagnetic_excursion [2] https://en.wikipedia.org/wiki/Laschamp_event https://en.wikipedia.org/wiki/Laschamp_event [3] https://en.wikipedia.org/wiki/Geomagnetic_reversal https://en.wikipedia.org/wiki/Geomagnetic_reversal
pacaro 3y ago
Approximately when the Neanderthals disappeared, cave art starts appearing, and Homo Sapiens arrive in Europe
- jandrese 3y ago
  I feel like the first two clauses are explained neatly by the third clause.
  - pacaro 3y ago
    Unpicking causality at a distance of 40ky is certainly problematic

89 points by wglb 3y ago

ClassyJacket 3y ago

Cosmic rays: interfering with Mario 64 speedruns since 38,976 BC

dveeden2 3y ago

I misread the title as "Comic rays..."

skhr0680 3y ago
It's how that font came to Earth
- danparsonson 3y ago
  Ah, the old 'Pankernia' theory. I'll see myself out.

defrost 3y ago

Variations in cosmogenic radionuclides like beryllium-10 provide an independent proxy of how Earth's paleomagnetic intensity changed. Indeed, Panovska found that the average production rate of beryllium-10 during the Laschamps excursion was two times higher than present-day production, implying very low magnetic field intensity and lots of cosmic rays reaching Earth's atmosphere. Specifically, I'd guess, that twice as many cosmic rays reached the surface, at that location, than the mean present day average that reach the surface. * The location hedging is due to: magnetic field excursions, brief periods in which the intensity of the magnetic field wanes and the dipole (or two magnetic poles) that we're familiar with can disappear, replaced with multiple magnetic poles. The Laschamps excursion that occurred around 41,000 years ago is among the best studied. It features a low magnetic field intensity that implies less protection for Earth's surface from harmful space rays. So the magnetic sheilding in the upper atmosphere and further out "in space" had 'holes' and was not like the 'modern' IGRF. The Earth still had a denser lower atmosphere, though, which also provides protection from cosmic rays - geophysical air surveys for ground radiometrics have to calibrate for cosmic rays by running "stacks" .. survey lines high up in the air and prgressivel closer to the ground in order to estimate the cosmic falloff with atmospheric density for the duration of the ground survey. * "twice as many* is also a hand wave, cosmic ray energy has a spectrum and the changed geomag field would bend the pass through spectrum and likely allowed more high energy gamma's through .. the end result was the doubling of the creation of a proxy indicator.

littlestymaar 3y ago
> cosmic ray energy has a spectrum and the changed geomag field would bend the pass through spectrum and likely allowed more high energy gamma's through The earth magnetic field has no shielding effect on gamma rays at all (which are photons), only on charged particles (protons, electrons and their heavier variants: muons and hypothetically tau leptons but IDK if there are any of them in cosmic rays)
- defrost 3y ago
  The earths magnetic field traps charged particles (mostly protons and electrons) from the solar winds into large donut-shaped belts around the Earth, well outside of the extent of the atmosphere. It's these particle belts which filter cosmic rays (gamma radiation) and as the magnetic field fluctuates so too does the spectrum of high energy gamma radiation that makes it through the charged particle shielding, which is further filtered by the atmosphere. You're correct that there's no direct magnetic transformation of the incoming gamma spectrum, I was casually referencing the very real indirect effect.
  - littlestymaar 3y ago
    It's the first time I ever hear about such an effect and I admit I have a hard time believing it since the particle density is very low in the Van Allen belt. Do you have any source for that? (Google couldn't help)
    - defrost 3y ago
      The inner Van Allen donut is some 8,000 km thick (from ~1,000km above ground surface stretching out to ~8,500 km or so) and denser than the much much larger outer donut that (IIRC) stretches from 3 earth radii to 10 earth radii. Low density but a lot of particles, many with high energy, sourced mostly from solar ejection, with cosmic particle and cosmic gamma strikes on the upper atmosphere sourcing a significant chunk of additional charged particles for the inner belt, and both receiving decay particles from cosmic high energy gamma and cosmic charged particles strikes on particles already within the belts (at a proportionatly lower rate than those from upper atmosphere interaction). It's a Pachinko game, the density is low but the strikes do happen. The effect I refer to is studied on again | off again (eg: iirc, Robert Forward looked at "draining the Van Allen belts" to remove charged particles and there were papers looking at the sheilding factor for cosmic that would be lost) but largely tossed in as an "and also" .. eg: https://science.nasa.gov/science-research/earth-science/earths-magnetosphere-protecting-our-planet-from-harmful-space-energy/ https://science.nasa.gov/science-research/earth-science/eart... our magnetosphere shields us from erosion of our atmosphere by the solar wind (charged particles our Sun continually spews at us), erosion and particle radiation from coronal mass ejections (massive clouds of energetic and magnetized solar plasma and radiation), and cosmic rays from deep space. Most of the focus tends to be on the cosmic charged particles with mass rather than the massless photons. I admit I've largely only concerned myself with the fall off of the gamma spectrum through the atmosphere, but I've had past discussions with some on the fall off of the (cosmic) gamma spectrum as it approaches Earth and figure there must be papers on this about. The Chandra X-ray Observatory calibration procedure papers would likely be our best bet for a good source, the satellite has an eccentric obit ( Perigee altitude 14,307.9 km, Apogee altitude 134,527.6 km ) which puts it fully outside the denser high energy inner belt but half in | half out the less dense outer belt. There would have to be a procedure to factor out the variation in "local" X-Ray events as it moves about the planet in order to sharpen the data from the two Grating Spectrometers

mfritsche 3y ago

https://en.m.wikipedia.org/wiki/The_Seven_Daughters_of_Eve https://en.m.wikipedia.org/wiki/The_Seven_Daughters_of_Eve a few of the seven mothers of Eve seem to have lived around the same time. Just an observation.

defrost 3y ago
Interesting book, very hard to tell whether you're a serious twue believer or just engaged in some wry leg pulling: Howy Jacobs in Nature labelled the book as semi-fictional with the majority of the information "the accounts of the imagined lives" of human ancestors. He commented: "All this made me feel that I was reading someone's school project, with influences from The Flintstones cartoon series, rather than a treatise by a leading academic." The wikipedia summary didn't give a time frame for the book events, however the Laschamp event was 42 thousand years before prest .. after the settling of coastal and much of inland Asia, Australia, etc. It seems a little near in time for a literal bottleneck of seven women's genetics, I feel even Bryan Sykes would have pushed back his dating of the seven clan mothers further than a mere 42 kyears. https://en.wikipedia.org/wiki/Laschamp_event https://en.wikipedia.org/wiki/Laschamp_event
- rsync 3y ago
  "It seems a little near in time for a literal bottleneck of seven women's genetics ..." The bottleneck was figurative. No actual bottle was involved. (I have five figures of karma with which to fight this battle).
  - o11c 3y ago
    A lot of people misunderstand figurative bottlenecks too. The "7 women" does not mean anything like "only 7 women existed at the time". Particularly: * other women existed who only had sons, or whose daughters only had sons, etc. See https://en.wikipedia.org/wiki/Galton%E2%80%93Watson_process https://en.wikipedia.org/wiki/Galton%E2%80%93Watson_process (about surname extinction, which is basically the same thing other than sex-specific polygamy effects) * other tribes existed (or split off) who later faced extinction due to being outcompeted by these 7 tribes.

euroderf 3y ago

In the 60s I read a (crackpot?) theory that the Old Testament was not kidding when it says people lived hundreds of years, and that a sudden influx of cosmic rays could explain a nexus of Biblical events - the dispersion of a persistent global cloud cover that had existed until then, the rain & flooding event that Noah rode out, and the subsequent reduction (thanks for nothin', cosmic rays) in human lifetimes.

xattt 3y ago
If anything, cosmic rays would (stochastically) seed clouds. Constant cloudiness would suggest that Earth was under bombardment at that time. (1) https://www.science.org/doi/10.1126/science.1076964 https://www.science.org/doi/10.1126/science.1076964
i67vw3 3y ago
Fun thing about the Noah 'story' is that the exact same story is present in Hinduism. It goes something like, God selected a righteous person to help humanity survive the flood. He has this individual built a big ship in which humanity and animals can survive. The only difference in the story is that God took a form of small fish which grew larger as the flood date came close. In the end it became so big that it was able to steer the big ship during flood waves. https://en.m.wikipedia.org/wiki/Matsya https://en.m.wikipedia.org/wiki/Matsya
- Tuna-Fish 3y ago
  The story in the Vedas probably has the same origin as the Mesopotamian flood myths. The oldest surviving Akkadian and Sumerian references to the flood precede and are pretty close in time to the Aryan expansion to the Indian subcontinent, and the Mesopotamian cities had long-lasting trade, cultural and military links to the peoples living in the Iranian plateau. I love speculating on the origin of the flood myths. My personal favorites are long-lasting oral traditions about the Black Sea flood and the Persian Gulf flood, both of which were rapid, catastrophic large-scale floods of large areas that were previously settled by humans. Sadly, the true origin is probably a lot more banal -- the oldest surviving fragmentary literary evidence refers to the specific city that flooded, Shuruppak, or modern Tell Fara. There is indeed a significant flood layer there (60cm of alluvial sand!) at about the right time (2900BC), but this was left by a normal river avulsion that created a violent but local flood.

stanac 3y ago

> periods in which the intensity of the magnetic field wanes and the dipole (or two magnetic poles) that we're familiar with can disappear, replaced with multiple magnetic poles If this was a basis of a movie plot I would think how stupid the movie is. Apparently it was normal for earth to have more than two magnetic poles before earth core started to solidify [0]. Was earth core composed of multiple elements where each had two magnetic poles? Also somewhat relevant wiki articles: Geomagnetic excursion [1], Laschamp event [2] and Geomagnetic reversal [3]. [0] https://www.popularmechanics.com/science/environment/a21528/ancient-earth-magnetic-field/ https://www.popularmechanics.com/science/environment/a21528/... [1] https://en.wikipedia.org/wiki/Geomagnetic_excursion https://en.wikipedia.org/wiki/Geomagnetic_excursion [2] https://en.wikipedia.org/wiki/Laschamp_event https://en.wikipedia.org/wiki/Laschamp_event [3] https://en.wikipedia.org/wiki/Geomagnetic_reversal https://en.wikipedia.org/wiki/Geomagnetic_reversal

pacaro 3y ago

Approximately when the Neanderthals disappeared, cave art starts appearing, and Homo Sapiens arrive in Europe

jandrese 3y ago
I feel like the first two clauses are explained neatly by the third clause.
- pacaro 3y ago
  Unpicking causality at a distance of 40ky is certainly problematic