In people vitamin D is created through effects of UV light on the skin (source) on Earth the Ozone layer and Earth's magnetic field protect us from many harmful effects of the sun.

Is there anyplace in the solar system where people could get enough sun to make vitamin D, without other significant health risks?


  • Anyplace in the solar system = planet, moon, other natural or man made object
  • Significant health risks = without exceeding OSHA or at the very least the NASA version, for exposure
  • Windows, translucent suits or other man made filters using current technology that allow exposure to sun light, that will create vitamin D, while allowing safe exposure would be acceptable solutions.
  • $\begingroup$ Off Topic but relevant: grc.com/health/Vitamin-D.htm $\endgroup$
    – Sukima
    Nov 5, 2014 at 21:16
  • $\begingroup$ Anywhere within about 5 meters of a good sun lamp. $\endgroup$
    – Schwern
    Feb 15, 2015 at 18:13
  • $\begingroup$ Maybe off-topic; more relevant as a health question. As a health question, one might even ask: is the UV dose necessary for adequate production of vitamin D an unsafe dose with respect to skin cancer risk? In other words, is it even possible for a human to meet his/her need for vitamin D solely by manufacturing it, without risk of skin cancer due to excessive UV exposure? Or is the only safe way to meet vitamin D needs via dietary sources or supplements? $\endgroup$
    – Anthony X
    Jun 13, 2015 at 21:45

2 Answers 2


On any planet, moon or other natural or man made object, other than Earth, vitamin D is definitely going to be the least of your worries.

There is nowhere you could go without either a protective suit or a protective capsule/building.

On Earth, wearing a protective suit or staying indoors will remove your ability to make sufficient vitamin D, so other locations are guaranteed to be worse - they all have significant health risks!

  • Rickets is one of the commonly known symptoms of Vitamin D deficiency, and this is incredibly common here on Earth among those at high latitudes, and those with high melanin levels living in medium latitudes, indicating that the UV absorbed by the skin here on Earth is close to being insufficient.

I'd suggest vitamin tablets: problem solved

Alternatively, use UV lights, as NPSF3000 suggests.

  • $\begingroup$ Alternative Solution - UV emitting lights. $\endgroup$
    – NPSF3000
    Nov 5, 2014 at 12:27
  • $\begingroup$ Well considering when we evolved to produce Vit-D from UV we were pretty much naked. Deficiency in modern times could be attributed (at least partially) to our need for clothing. Maybe? $\endgroup$
    – Sukima
    Nov 5, 2014 at 21:15
  • 1
    $\begingroup$ @Sukima, I'd attribute living in higher/lower latitude and staying indoors (esp. during winter) as more important. You don't need a ton of sun to make D, even wearing clothes - e.g. sunsmart.com.au/vitamin-d/how-much-sun-is-enough $\endgroup$
    – NPSF3000
    Nov 6, 2014 at 0:32

In your question, you're approaching the effective dose from a single entity standpoint - location based intensity (power per unit area) of radiation. Problem is, that you're neglecting other points to absorbed dose, such as exposure time and effectiveness of shielding. These could be anything, from microseconds long exposures to high intensity radiation, longer but still short exposures of smaller parts of the total surface area at the time, to reducing incident intensity by shielding.

So the answer to your question is actually - anywhere. Depends. If you can thwart against other threatening effects of being in close proximity to the Sun, such as heat, particle radiation and so on, chances are good that you'll be more than capable of dealing with UV radiation too. All you need is some areas that are partially or fully opaque to this wavelength and limit your exposure time to acceptable dose of radiation.


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