Intuitively understanding the size of Earth
If you build a minute model of the Earth with the diameter diameter equivalent to halve the width of a soccer field (~25m),
then a model soccer field on that model Earth would have a with of approximately half a human hair (~0.05mm). Or a thin one.
It's the same ratio!
- 12,736km / 25m = ~ 500,000
- 25m / 0.05mm = ~ 500,000
See?
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How this relates to the comparison for gaining a direct true intuition for the size of atoms
Interestingly the exact same factor that perhaps can suffice to make a true intuitive understanding of the size of atoms possible,
the factor of 500.000, also may make possible a true intuitive understanding of the size of Earth.
Bigger sizes fundamentally not directly intuitively comprehensible
Any sizes much beyond the size of the Earth are hopelessly beyond true direct intuitive comprehensibility.
- For interplanetary distances spaceship travel times can give a bit of a hint but that is far from a true direct intuitive comprehension.
- For interplanetary distances only relative size comparisons to something of a size already beyond direct everyday experience are possible.
- For interstellar distances even that works barely. Stars are brutally far apart in terms of say our suns diameter. Much much much more so than planets are apart in terms of their diameter.
Relative comparison for stars (not at all sufficient for a direct true intuition)
Sun and currently nearest star:
- Sun 695508km / 5,000,000,000,000 = ~0.1mm (hair diameter)
Distance to proxima centauri (currently nearest star) 4,2465LJ* 9.46*10^12km/LJ = ~40*10^12km
Distance to Neptune ~30AE*~150Gm/AE = ~ 4.5Tm
- Distance to Neptune: ~ 4.5Tm / 5,000,000,000,000 = ~1m
- Distance to proxima centauri: ~40*10^12km / 5,000,000,000,000 = ~8km
One of the biggest stars in "reasonable" interstellar distance (same scale):
- Distance to Betelgeuse is ~100x farther than to proxima centauri. Scaled down hair-diameter-sized sun that makes 800km
- Diameter of Betelgeuse is ~1000x the diameter of the sun. Scaled down hair-diameter-sized sun that makes 10cm
These supergiant stars are often so big and dilute that they are basically a "hot vacuum".
