Knowledge

If Earth orbited a blue supergiant star at the habitable zone, would going to the beach be a bad idea no matter what? Would people get sunburned within seconds?

No.

Sunburn would not be a risk. Ozone layers don’t just shield against ultraviolet radiation, they are also created by ultraviolet. Specifically, ozone layers are created by higher frequency ultraviolet radiation, the ultraviolet C-band, and the output of UV-C radiation increases with a star’s surface temperature.

This leads to the ironic situation where cooler red and orange dwarf stars, which generate some skin-burning UV-A and UV-B but little ozone-generating UV-C, would have Earth-like planets with higher risk of sunburn than Earth.

Meanwhile, stars hotter than Sol, like blue supergiants, would have Earth-like planets with dense, potent ozone layers that prevent sunburns at the surface. You might actually need tanning booths and vitamin D supplements.

You’ll fry faster under the rays of Epsilon Eridani than Sol, and you’ll fry faster under the rays of Sol than Sirius.

The real problem with blue supergiant stars is their atmosphere-stripping solar winds and lifespans of merely tens of millions of years. A planet wouldn’t finish forming before the star supernova’d.

(Yay! Our beaches just finished forming! We can go… [BOOM])

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