APOD: Moons and Jupiter (2009 Jul 14)

[NoelC]

I cannot begin to imagine, sitting here in this air conditioned office with a full stomach and a cup of coffee and with Pandora playing my favorite music, how unbelievably hard it must have been for very early Man, in his ignorance and with a lifespan of only one or two decades or less, to survive. I'm sure most evenings he or she was passed out from the exhaustion of trying to make ends meet (e.g., get enough sustenance to survive the day while enduring the misery of infections, parasites, fights with other people and animals, etc.) It's hard to think that many would have had the time prior to "modern civilization" to sit back and look at the stars much for other than a brief diversion. And that's even considering they had minds every bit as complex as ours going a long way back. They must have been bored senseless - in those brief moments when physical needs did not dominate their senses.

Not long ago I visited the sites of many petroglyphs in the American west, some well off the beaten path and quite clearly authentic. Primitive people of only HUNDREDS or a very few THOUSANDS of years ago were clearly far more preocupied with the sizes of various parts of the bodies of their leaders, the suffering they imparted on others (disembodied heads being carried around, for example), and of the animals they kept/hunted for food, than with the little lights in the sky at night. Notably there really are images that look suspiciously like beings in space suits; perhaps that was just early cliff carving sci-fi. I recall seeing only a very few images of the sun, let alone Jupiter.

-Noel

[Chris Peterson]

I cannot begin to imagine, sitting here in this air conditioned office with a full stomach and a cup of coffee and with Pandora playing my favorite music, how unbelievably hard it must have been for very early Man, in his ignorance and with a lifespan of only one or two decades or less, to survive. I'm sure most evenings he or she was passed out from the exhaustion of trying to make ends meet (e.g., get enough sustenance to survive the day while enduring the misery of infections, parasites, fights with other people and animals, etc.)

I don't think that is necessarily an accurate description of primitive life. People are, and were, social animals. They very early on built societies and pooled resources. There is evidence of art and music starting tens of thousands of years ago. They had burial rituals, and they took care of the sick and injured. Many must have lived in reasonably rich environments, where securing food wasn't a never ending ritual of exhaustive proportions. You can look today at social apes, and they spend a lot of time relaxing, lying around, and playing. With a superior human intelligence, I don't know why early tribes wouldn't have been able to do the same. There are a few remaining subsistence tribe/societies even today, and they enjoy ample time for recreation and relaxation.

[NoelC]

Perhaps I am being too pessimistic about early life, that's possible.

On the other hand, we can see that the Earth's population didn't explode until very recent times. But perhaps that was when relative comfort gave way to our modern life of outright luxury.

I do recall seeing where Ancestral Poebloans appear to have made special places with walls in their cliff dwellings for old folks, who were more likely to fall off the edge. That does imply a certain amount of extra energy available to take care of the aged.

-Noel

[giope]

going through the "Astronomy Picture of the Day" site, I found on the 2009 July 14th a picture which I was a bit astonished about.

indeed, Jupiter moons align along a direction which is not parallel to the Ecliptic (see, for instance, the attached picture taken from Linux "Stellarium"). I also have some perplexity on the brightness of Jupiter moons: it seems unlike to me that clouds can reduce the brightness of Moon to the extent that a picture can record both Moon and giovian moons. Finally, the leftmost Jupiter moon is a bit less than half a degree from the rightmost one (see the Moon diameter for comparison) which is not the actual angular distance for a terrestrial observer.

is there anyone that can help me in undestanding how the picture has been taken or providing me with picture details (film speed or equivalent for digital picture, time of exposure, f: number, time of the day, co-ordinates of the location, whether there has been magnification of the area where Jupiter and its moons are)?

thanks

[geckzilla]

Giope, I merged your post with the existing discussion on this APOD. I hope you do not mind. As you can see, you are not the only one who was astonished. Perhaps the answers you seek are in the thread already.

[neufer]

going through the "Astronomy Picture of the Day" site, I found on the 2009 July 14th a picture which I was a bit astonished about.

indeed, Jupiter moons align along a direction which is not parallel to the Ecliptic.

They look pretty close to being parallel to the Ecliptic to me
but that's only because Jupiter's equatorial plane is 1.3° from Ecliptic.

All big moons, with the exception of "johnny come lately" moons like Triton and our own Moon,
lie close to their planet's equatorial plane (even Charon!) and not to the Ecliptic or to the planet's orbital plane.