[animaomnium]

Very interesting paper! Proposes (with lower bound of 1.3% chance) that the solar system may have passed through a local interstellar cloud, which would have caused the heliosphere to shrink to smaller than the orbit of the earth (0.22 au) some 2-3 mya. This may have affected the Earth's atmosphere and climate. Scroll down for some cool illustrations of a simulation showing how the heliosphere would have been tiny with an elongated tail in a denser interstellar medium. There's also a map showing the interstellar cloud relative to the trajectory of the solar system.

[delichon]

> This may have affected the Earth's atmosphere and climate.

Adding uncertainty to climate forecasting models. Can we detect or predict changes to the interstellar medium in our path through space and improve forecasts with that? Maybe we could at least put an upper bound on the magnitude of the effect.

[gerad]

I learned this in the Cal Academy of Sciences the other day! Apparently we’re about halfway through a region of less interstellar activity.

https://en.m.wikipedia.org/wiki/Local_Bubble

[dylan604]

That's one of those fun astronomy topics that is mind boggling to think of the forces involved to diminish the effect of Sol's solar radiation to that level.