What we call lunar eclipses are what the inhabitants of the Moon would call solar eclipses and what we call solar eclipse they would call Earth eclipses, if they used similar terminology.
- During a solar eclipse, something appears to change with the sun, but appearances are deceptive: all that a so-called "solar" eclipse means is that the observer happens to be in a small region a few miles across on earth; one can easily drive to a different place and see that the sun is unaffected and continues to shine as usual. Despite the name, a solar eclipse is really an event about a small patch of earth.
- During a lunar eclipse, something appears to change with the moon, and this is right! The moon really does fall under shadow, something that's true wherever the observer may be. A lunar eclipse really corresponds to something happening on the moon.
Of course if you define away the difference by saying that eclipses are only about a specific observer at a specific point on earth, there is no difference, but that's not the point being made.
But it's possibly cultural what you think of as an “eclipse”. In Indian languages, the word from Sanskrit used is grahaṇa, which is from the verb for seizing, holding, catching, capturing, etc. So “solar eclipse” and “lunar eclipse” are literally “sun-capture” and “moon-capture”. Now from a very literal reading, neither of those is real: neither the sun nor the moon is really seized or captured anyway.
But based on the connotation that I think most people have, we can say:
* During a solar eclipse, you may think something's happening to the sun, but that's not real; that's only virtual.
* During a lunar eclipse, you may think something's happening to the moon, and that's real.
So I hope we can agree that there is something that's “real” during a lunar eclipse and not during a solar eclipse (namely, the corresponding named body being physically affected in some way); whether the word “eclipse” carries that connotation to you is of course something for only you to say.
No. I understand what you're saying, but it is simply not true that nothing is happening to the sun during a solar eclipse. Something is happening to the sun: it is being blocked from your view by the moon. It is perfectly analogous to what happening to the moon during a lunar eclipse: it is being blocked from the sun's view by the earth. The situations are exactly the same except for two things: the scope, and the perspective of an earth-bound observer. But IMHO those differences are not nearly enough to warrant labeling one of those "real" and the other one "virtual". They are both equally real.
At this point we're just debating the meanings of words and phrases like "something is happening to the sun" and whether being blocked from the view of someone on earth counts as something happening to the sun; one can very well argue whether shadows are real ("of course it's real, you see it right there" versus "no a shadow has no physical existence, it just looks like there's a dark object on the ground") and so on. At some point one ought to grant that others attach subtly different connotations to words.
But that is simply not true. An observer on the sun can tell, and the observation is both easy and significant: it would look like a transit of the moon across earth that passes over Europe.
During a solar eclipse, someone on the sun would hardly notice. The surface temperature does not change; the brightness does not change; the earth is about a 100 million miles away and occupies less than 10^-7% of the sun's sky (18 arc seconds; compare with the ~30 arc minutes that the sun or moon occupy in earth's sky). An observer on the sun would need to have very good optical instruments to take note of the entire earth in the first place; let alone the patch of earth a few miles across that is experiencing a total solar eclipse. Unless they were looking for it, they would not be aware of (what the earthlings call) a solar eclipse taking place.
(During a solar eclipse, we people on the earth do notice. The sun is hugely significant to the earth physically even though the earth is barely significant to the sun; the temperature can fall by maybe 15 degrees Celsius; people in the affected area of earth are plunged into darkness, etc.)
As a physically significant phenomenon, what's real during a solar eclipse (in somewhat the same way as a lunar eclipse) is happening on earth; if we called it a terrestrial eclipse it would be fairly real, but is the sun significantly affected? I'd say not really.
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Now, as this is my last post, there are a few philosophical issues this conversation has brought up:
- One is a question of ontology: What is "real"? I think people can differ in the level of how physical/material their ontology is; certainly everyone would agree about a visual spectacle taking place, but some would consider more "physical" phenomena more real (as in my earlier remark about whether shadows are “real”), and a brightness-and-temperature difference over half the entire moon is surely a physically more significant event (to the moon) than some faraway object casting a shadow on another faraway object would be to the sun.
- The second is a question of semantics: What connotations does the word "eclipse" carry? To some people, it carries connotations (e.g. "X-adj eclipse"="X experiencing a seizure") such that, for instance, a "solar eclipse"="sun being darkened" is only appearance not reality, while "lunar eclipse"="moon being darkened" is both appearance and reality.
- The third is a question of interpretation/hermeneutics. When I read something, I'm trying to see: "Is there some interpretation under which what I'm reading is correct?" The question of "Is there some interpretation under which the author of the above email is wrong, and solar eclipses are similar to lunar eclipses?" is not very interesting; of course the answer is yes, and in my earlier comments I've mentioned at least three interpretations under which the author is wrong. Certainly, it's not the language I'd use: before reading the post I'd never have described lunar eclipses as real and solar eclipses as virtual, and I probably still won't. Maintaining that the author is wrong does not challenge my perspective or contribute anything new to my life. I feel secure in my understanding of eclipses, and if someone has a different perspective, it does not feel like my perspective is being questioned; it's just an opportunity. On the other hand, "Is there an interpretation under which the author is right?" (the principle of charity) is more interesting, and having newly experienced this perspective I've been defending an answer of "yes": yes, not only is there a combination of connotations of "solar eclipse" and "real" under which a so-called solar eclipse is not a "solar-ly" significant event (thus not "real" in that sense), but also it's quite a fresh way of looking at things and appreciating how, even though both appear the same to us, one (which we call a "sun-seizure") is an event of significance only to us puny humans on earth and the sun is unaffected, while the other is truly, improbably, a case where the earth (our home!) has an unmissable effect on the moon, a case where our visual perception, of the moon falling into shadow, is actually correct, something contrary to our perception being so frequently wrong in the astronomical domain where for instance the sun and moon and stars appear to rotate around us every day and night but reality is different.
That doesn't make the event any less real. An event doesn't have to be dramatic to be real.
• “solar eclipse = sun gets darkened” is only appearance, not reality.
• “lunar eclipse = moon gets darkened” is both appearance and reality.
(I can guess what the response is going to be: either “that's not what ‘eclipse’ means”/“why care about that?”, or “but the sun does get darkened, as viewed from earth”. Thus the conversation goes in circles. Really I should stop; I've said all this already.)
If you're going to question people's perspective, tell them this instead of telling them that solar eclipses are virtual.
During a lunar eclipse, the earth projects its shadow on the moon. During a Solar Eclipse, the moon projects its shadow on the earth. Only the shadow is smaller. I'm not sure what makes lunar eclipses more real.