Investigation: UV radiation

UVA, UVB, UV Index, and SPF.  Here are some things I kind of knew about - UVA and UVB are bad, and SPF is good - but I didn't really understand.  What started me thinking about this was a set of eclipse glasses I bought from Amazon that was later removed, maybe because they were fake.  But why does that matter?  How would I know?

And can I buy a tool to help investigate this?

What is all this stuff

Ultraviolet light is light with wavelengths slightly shorter than that of visible light, with the following ranges:

    UVB: 280-314nm

    UVA: 315-400nm

UVA and UVB cause different kinds of damages to the human body.   As a broad generalization, UVB causes short term issues like sunburn and UVA causes long term issues like skin cancer.  Remember that UVB light at 314nm will affect you approximately the same as UVA light at 315nm, so the effects are not as clear cut as the broad generalization.

The nice thing about sunburn (and UVB), so to speak, is that it helps you and your body know that something bad is happening so that you both can protect yourselves.  You get out of the sun.  Your body builds melanin to protect against UVA and UVB.  Let's remember this for later.

UV Index and SPF

It's probably clear that people learned about sunburns earlier than skin cancer and when we designed our products to prevent the harmful effects of the sun, we designed products to block UVB (sunburns).

Then we, as a society, created the UV Index to measure UVB radiation.  And we created an SPF rating for products that measure how much UVB radiation it blocks.

Here is how the UV Index is calculated: https://www.epa.gov/sunsafety/calculating-uv-index-0

Wavelength		Weight
290nm		15
320nm		5
400nm		3

From the above grid, you can see that the UV Index weights UVB higher than UVA because UVB causes more sunburn.  This indicates that the UV Index is not suitable for determining the long term effects of sun exposure (UVA).  What I find most interesting about the way the UV Index is calculated in the United State is that it uses elevation, cloud cover, and ozone measurements to estimate ground level exposure, instead of actually measuring it.

So if we are relying on high-SPF rated sunscreen to protect us from the sun, what are we doing?  We are preventing our skin from being burned which encourages us to stay outside longer, exposed to cancer-causing UVA rays, all while blocking our natural melanin creation which is supposed to protect us from UVA.  This sounds a lot like a recipe for greater long-term skin damage, which is probably what happened.

Broad Spectrum

What about broad spectrum SPF sunscreen?  That must block UVA and UVB.  According to thesunscreendoc.blogspot.com/2015/08/, which I did not verify, most broad spectrum sunscreens just block a small amount of UVA.  The only ingredients that protect against both are zinc oxide, Tinosorb M, and Tinosorb S.

The writer of this blog has created a sunscreen company, selling the Sun Whip brand sunscreens, so it can't be taken as unbiased, but everyone does seem to agree that zinc oxide blocks UVA and UVB.  But zinc oxide is super white and looks pretty bad.  However, that's "old" zinc oxide; now we have encapsulated zinc oxide, which is supposed to go on clear. 

Excited, I decided to test that claim with derma-e, which the EWG seems to like.  Unfortunately, it's "clear zinc oxide" is still white and difficult to spread on my hairy skin.

This blog seems to like the Sun Whip brand sunscreens from the blog-doctor above, among others: https://beautyeditor.ca/2017/06/19/zinc-sunscreen-for-face.

And, for good measure, here is a list of bad sunscreens for kids, also from the EWG.

The sunscreen doc also says that windshields do not block UVA.  Let's check that out later.

Tools

I found a handful of tools that could measure UV light, ranging from $25 to $250.  Unfortunately, the only brand that published the spectral response graph of their sensors was Solarmeter, the one that costs $250.

The Solarmeter Model 5.0 UV Meter measures UVA and UVB: https://www.amazon.com/dp/B01GT4EID0

This graph is nice, because it covers UVA and UVB, with an emphasis on UVA (the high response at the right-hand side of the graph).

Solarmeter also has a Model 6.5 UV Index Meter that tries to calculate the UV Index.  However, it appears to be the same device as above with an added filter that blocks UVA light, further indication that UV Index ignores UVA exposure.

The $250 price tag is unfortunate because all Solarmeters cost $250, even the visible light meter, which is simply a $2 sensor, a chip, a cheap screen, and a button.  So, I did a little search for UV sensors to see if I could build my own meter.  Adafruit has two UV sensors, about $6 each:

GUVA 1918 (Analog): https://www.adafruit.com/product/1918

VEML 6070 (I2C): https://www.adafruit.com/product/2899

Again, unfortunately, the spectral graph of the Solarmeter is much nicer than these two, so that's the one I bought.

Measurements

So now that I have this tool, what science can I do?

First, the noon-day sun where I live measures 4.5 mW/cm2.

Through my car windshield: 0

Through my car windows: 0

Through my car sunroof: 0.2

Through my wife's car windshield: 0

Through my wife's car windows: 2.0  (that's pretty high)

My car has a darkening film, which is probably why my car has higher UV protection.  After taking these measurements, we will likely put film on my wife's car too.

My wife's rather high reading is consistent with the idea that car side windows block UVB but not UVA.  I would like to test this with UVA and UVB band pass filters, but sometimes science is just too expensive and it'll be cheaper to just put film on the car.

My sunglasses: 0

Real eclipse glasses: 0

Possibly-fake eclipse glasses: 0

House windows: 0.4 (but more measurements are needed for different days and sun positions)

Investigation: Jews

I have heard a few things said of the Jews at my Christian church that, when coupled with the messages of the Old Testament, prevent me from forming a cohesive story in my head of what is a Jew.  I get the impression that many pastors have a very narrow and biased view of Jews, so I thought I'd test this view.

Luckily, a friend of mine happens to be a Jew, rather intelligent, and the son of a professor of Jewish studies.

Roughly, here is the portrait of Jews as painted in the sermons I have attended.  Jews are roughly the same as Christians except:

• They believe in the Old Testament and not New Testaments
• They follow (or should follow) all the rules in the Old Testament

So I asked him two questions.  Or, as it turns out, three.

Question 0

"Can I ask you some questions regarding what Jews believe?"

Aaron immediately responded with "What do Christian's believe?"  I responded with something that roughly encapsulated Catholics and Protestants, but he reminded me of the other Christians I might be implicitly ignoring - Lutheran's, whom I know nothing about, and Mormon's, who non-Mormon's generally ignore. 

And then he asked a more specific question, "How many Christians are pagans?"  I had to admit that I don't know what a pagan is, which was apparently the correct answer.  There are Christians who believe that Jesus was born a man and became divine sometime during his life.  This is Adoptionism, which my have been practiced in the early church before the doctrine of the Trinity was created (in the 2nd century, with refinements through arguments into the 4th century).  His implication is that if someone worships a man, born mortal and made divine, than that person follows a pagan religion.

To top it off, some Christians don't believe in the Trinity.

So what do Christians believe?  Each sub-group has specific beliefs, and believes that the other sub-groups, who have differing beliefs, are wrong.  And if you were to graph all these beliefs, for all Christians, the centroid of those beliefs may not represent any group.

The same is true of the Jews.  There is no simple description of what Jews believe because the individual beliefs vary widely.  Also, the traditions of the Jews have changed over time, perhaps as a result of wars, raids, etc.  There is a tribe of Jews recently discovered in Africa that did not experience persecution by Christians and Muslims and their traditions may hint at what the old traditions were.  In particular, they open their doors at the beginning of some particular ceremony instead of the end; Jews in the rest of the world open their doors at the end, after the meal has been consumed, because during Islamic occupation any house visibly having a feast would be raided.

From a much earlier conversation, I was taught about the current establishment of Jewish matrilineal descent (children of Jewish mothers are born Jewish) was a change from the traditional patrilineal descent (children of Jewish fathers are born Jewish), based on war casualties.  So many men were dying in wars that the culture would die if women could not pass on the culture.

Question 1

"I haven't seen much mention of Heaven and Hell in the Old Testament.  Do Jews believe in Heaven and Hell?" 

In many Christians' belief systems, the concept of Heaven and Hell is vitally important, perhaps of paramount importance.  If it is of such great importance, why did God not tell his chosen people about it?

Again, Aaron wasn't going to tell me what all Jews believe, or even what most Jews believe, and he wouldn't guess at what percentages believed what.  However, he would answer what, from his necessarily limited perspective, the Jews that he knows or heard about believe.

You can map the spread of Judaism with a tree, the root planted somewhere around Israel and reaching out to all the continents.  Every Jew is somewhere on the tree, and groups of Jews who live closer to each other are closer on the tree and more likely to believe similar things and have similar cultures.  On top of this, there are major cultural forces, like the various movements such as Orthodox Judaism, which catch on and homogenize the Jewish beliefs across cultures.

What we see is that many Jews are influenced by the major movements and also by their local environments.  Jews in North America are more likely to believe in Heaven and Hell than those in Israel because of the pervasive Christian culture in North America.

As for the Old Testament, there is no concept of Hell.  The word Sheol which is translated to Hell means either grave, or "that stinking pit outside the city," signifying an unpleasant place, but not one of eternal torment.

Incidentally, The New Testament does not support the current Christian idea of Hell as a place of eternal damnation either.

Heaven is slightly different.  There is no concept of the Christian Heaven in the Old Testament, but there are hints that something exists.  In particular, the thummim and seraphim are non-worldly artifacts, and if they are not of this world, and they are from somewhere, then there must be another place not in this world.  This is a far cry from a place of eternal bliss.

Aaron also had a comment concerning the carrot and stick approach to Heaven and Hell often used today to entice people to follow church teachings.  In Judaism there is not a concept of "if you don't follow these rules, bad things will happen to you."  Instead, they have "you will follow these rules."  There is no option if you want to live God's way.

Question 2

"Do Jews believe that all the books of the Old Testament are true?

It is taught in my church that Christians are expected to believe that all the books of the bible at true.  However, there seems to be a hierarchy in the Old Testament, with the Torah being more important than the rest.  What's up with that?

Aaron said that some Jews believe that all books in the Old Testament are true, just as some Christians believe that all books in the Bible are true.  However, most believe that some are stories.

In particular, the Old Testament, known as the Tanakh, is broken into three sections, the Torah (the first five books of Moses), the Nevi'im (the works of the Prophets), and the Ketuvim (the Writings).  The word TaNaKh, is formed of the first three consonants of Torah, Nevi'im, and Writings.  Here is a talk about the Dead Sea Scrolls, given by a Jewish scholar to Jews, where he describes "the Torah being big divine inspiration, the Prophets being a little less, and the Writings being, again, even less - a descending order of inspiration."  This description states that the books of the Ketuvim "do not present themselves as the fruits of direct divine inspiration."

In particular, Chronicles is currently part of the Bible, but the author is interpreting other books and we don't know if he thought he was writing a book or the Bible or we took his interpretive book and added it to the Bible.

My thought goes something like this.  The Jews have a very powerful pattern of passing information from one generation to the next, an extremely solid oral and written tradition and a history of unbroken ceremonies and lessons.  They are much, much better than Christians at preserving knowledge through the centuries.  So why is it that Christians do not use this amazing resource to help understand the Jewish Bible?  If Christians generally believe that the books of the Old Testament are true and Jews generally believe some are not-so-much, then it is highly likely that this particular Christian belief is a result of recent changes in mindset and thinking.

Missing Question 3

It was also my intent to ask him about the many laws the Jews are purported to follow, with The Old Testament often being referred to as "The Law."  This guy, describes the Torah as instruction and calling it Law is unfounded in scripture and against the general intention of forming a relationship with God.

In another conversation, it was explained to me that some of the Jewish laws are meant to protect the people from breaking the commandments.  For example, from Deuteronomy 14:21, "You shall not boil a young goat in its mother's milk," becomes "do not eat milk and meat together."  In order to guarantee that you never boil a young goat in its mother's milk, keep the two foods separate.  What if you have cows milk and lamb meat?  It should be okay, but how sure are you that your cow's milk is really cow's milk?  How sure are you that what you think of as lamb's meat is really lamb's meat?  The truth is that you cannot be sure, so better be safe than break a commandment.

Commentary

I have often been in situations where someone makes a claim about another group of people, not necessarily in a religions context.  In church, it is often a sweeping generalization of another religion and what people in those religions believe, be it Judaism, Buddhism, or any other.  I often wonder, why don't we just ask an intelligent Jew, Buddhist, or other?  I think we will often find that our simplistic notions are flawed.