Artificial lighting, huh?

Not all light is created equal.

Light is more important than just for illumination. The quality of
light has an impact on both the physiology of plants and the mental
health of human.

Recent advances in CFL (compact flourencent lighting) has resulted in
bulbs that are close the clour rendition index of the sun. Natural
solar light has an index of 100. Some CFL used in greenhouses now have
a CRI of 93, and those used in photography are around 93.

CRI is important to plants with regards to the quality of
photosynthetic radiation, meaning mostly red and blue light. It is
important that the artificial light created has the right balance of
these hues. But, other wavelengths also play an lesser, but equally
important role in plant health.

Humans seem to thrive better in natural sunlight than they do in
artificial light. This is a rather complex and not well understood
subject.

Besides the quality of light, one might also consider the cost of the
articial light. After all, the purpose of a habitat wal is to retain
atmosphere. What difference does it make if that protective shell is
steel, aluminium, or glass? There is probably a slight difference in
the cost, in terms of material and consturction time, between these
materials. But, will installing artificial light cost more than
installing windows in the habitat shell? Probably. Will the artificial
light be of sufficient strength and quality? Maybe, maybe not. Why is
it logical and cost effective to construct a habitat to be more
articial than the environment to which we hymans are adapted to?

If it is reasonable to deviate from the environmental norms to which we
are use to and doing so does us no harm, than it should be considered.
If there is no good reason to do so or if it might prove to be harmful,
then we mustn't make the change.

Deviating from the norm merely to embrace change is an insufficient
reason for making change.

rhc

--- In spacesettlers@yahoogroups.com, "Xenophile"