# How could the baseline of atmospheric neutrinos be as much as $10^7$ meters while exosphere (outer part of atmosphere) is at most 8e5 meters?

Atmospheric neutrinos correspond to neutrinos produced by the interaction of cosmic rays in the Earth atmosphere. The Earth atmosphere is at most $$800$$ km=$$8 \cdot 10^5$$ meters.

So how could the "baseline" (=distance of flight) of the atmospheric neutrinos be as much as $$10^7$$ meters, as stated in the Table of properties of atmospheric neutrinos in the famous (most cited book in particle physics) Particle Data Group review:

http://pdg.lbl.gov/2019/reviews/rpp2019-rev-neutrino-mixing.pdf

And bonus question: how could solar neutrinos have a baseline (it is stated $$10^{10}$$ meters) higher than 150 millions km= order of $$10^8$$ meters: that looks impossible?

Neutrinos produced in Earth's atmosphere have two opportunities to interact with detectors on Earth's surface: once on their way down from the sky, and again when they emerge unscathed on the other side of the planet. So the baseline is more like the diameter of Earth, which is about $$12.7×10^6$$ meters.
Re your bonus question: "million kilometers" is a stupid unit, and everyone makes off-by-thousand exponent-counting errors when using it. An astronomical unit is $$1.5×10^{11}$$ meters.