<p>For the last 10,000-1,000,000 years, we have cosmic ray tracks and gas products in meteorites. There has been a bit of a shift in angular distribution over the sky over the course of years-decades, but even that’s degrees, not radians or cycles.</p>

CC BY-SA 4.0
2022-10-27T23:24:07.330Z
needs supporting sources
uhoh
CC BY-SA 4.0
2022-10-31T00:17:52.867Z
For example, Scitech Daily's [Tree Rings Offer Insight Into Mysterious, Devastating Radiation Storms](https://scitechdaily.com/tree-rings-offer-insight-into-mysterious-devastating-radiation-storms/) links to October 26, 2022 Proceedings of the Royal Society's [Modelling cosmic radiation events in the tree-ring radiocarbon record](https://royalsocietypublishing.org/doi/10.1098/rspa.2022.0497) which goes into great detail
uhoh
CC BY-SA 4.0
2022-10-27T12:57:33.330Z
2022-10-27T12:57:33.330Z
caInstrument
<p>Is the flux of cosmic rays now greater than it was in past eras of the Universe, less than it was in the past, or is it roughly the same? Is the answer different depending on what type of cosmic rays we are considering (lower energy, higher energy, protons, heavy nuclei, etc.?)</p>

CC BY-SA 4.0
2022-10-26T14:42:52.550Z
For the last thousands of years we have C-14 and tree rings to measure the variation, that isn't a different 'era'.
Jon Custer
<cosmic-ray>
How has cosmic ray flux changed over time?
Alex319
# How has cosmic ray flux changed over time?

(Asked by: username_0 on 2022-10-26)

Is the flux of cosmic rays now greater than it was in past eras of the Universe, less than it was in the past, or is it roughly the same? Is the answer different depending on what type of cosmic rays we are considering (lower energy, higher energy, protons, heavy nuclei, etc.?)

**Tags:** cosmic-ray

> **Comments:**
> **username_1**: For the last thousands of years we have C-14 and tree rings to measure the variation, that isn't a different 'era'.  

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## 1 answers

### Answer by username_2 on 2022-10-27. Score: 1

For the last 10,000-1,000,000 years, we have cosmic ray tracks and gas products in meteorites. There has been a bit of a shift in angular distribution over the sky over the course of years-decades, but even that’s degrees, not radians or cycles.

> **Comments:**
> **username_3**: needs supporting sources  
> **username_3**: For example, Scitech Daily's [Tree Rings Offer Insight Into Mysterious, Devastating Radiation Storms](https://scitechdaily.com/tree-rings-offer-insight-into-mysterious-devastating-radiation-storms/) links to October 26, 2022 Proceedings of the Royal Society's [Modelling cosmic radiation events in the tree-ring radiocarbon record](https://royalsocietypublishing.org/doi/10.1098/rspa.2022.0497) which goes into great detail  

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