APOD: Moons and Jupiter (2009 Jul 14)

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Expand view Topic review: APOD: Moons and Jupiter (2009 Jul 14)

Re: Picture of the 2009 July 14

by neufer » Wed Feb 03, 2010 8:20 pm

giope wrote: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.

Re: Moons of Jupiter (2009 July 14)

by geckzilla » Wed Feb 03, 2010 6:06 pm

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.

Picture of the 2009 July 14

by giope » Wed Feb 03, 2010 5:57 pm

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
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Re: Moons of Jupiter (7/14/09)

by NoelC » Fri Jul 24, 2009 8:25 pm

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

Re: Primitive People

by Chris Peterson » Fri Jul 24, 2009 8:14 pm

NoelC wrote: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.

Re: Primitive People

by NoelC » Fri Jul 24, 2009 8:00 pm

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

Re: Moons of Jupiter (7/14/09)

by BMAONE23 » Fri Jul 24, 2009 2:46 am

Hunter Gatherer societies were also statistically much smaller than today's megaplex societies. Per Capita, there might have been as many individual people that were interested in those sparks in the night sky as there are today (say 1 in 100). After all, cataloguing those points of light does little to put food on the fire and so had little importance to the society de jour, and with only 10 people in a given village with this particular interest, most communications would have been verbal rather than written. The individual with interest in the stars though, could possibly have created Star Maps on the media of the time (painted skins) and took these to summer gatherings where they could find others of similar interests to discuss their observations. A gathering of 10,000 people could provide 100 or more persons of similar stellar interests. Whereas today, with 7,000,000,000 prople worldwide, that gives you 70,000,000 people to discuss things with.
And Painted Animal Skins typically won't last much beyond the burial of their owner.

Re: Moons of Jupiter (7/14/09)

by neufer » Fri Jul 24, 2009 1:00 am

apodman wrote:There is probably a difference between the oldest surviving star map and the first one. The first one was probably scratched in the dirt and at best only lasted until the next rain.
There are many surviving texts much older than 14 centuries.
My guess is that there is more discussion of mothers-in-law in them than of stars.

In any event, my hypothesis stands that most hunter-gatherer societies (whether ancient or modern) held little interest in the stars.
Agricultural and commerce based societies were the first to find a really practical value to astronomy.
apodman wrote:Where I was schooled they taught some courses in cultural anthropology (which deals with the present) and some in historical anthropology (which deals with the past). The subjects are related but the research methods are necessarily different. In the case of American aborigines, we have an arguably advanced stone age culture living concurrently with more modern cultures. This provides an opportunity to infer historical anthropological ideas from the study of a living culture.

Re: Moons of Jupiter (7/14/09)

by apodman » Thu Jul 23, 2009 9:50 pm

There is probably a difference between the oldest surviving star map and the first one. The first one was probably scratched in the dirt and at best only lasted until the next rain.

---

Where I was schooled they taught some courses in cultural anthropology (which deals with the present) and some in historical anthropology (which deals with the past). The subjects are related but the research methods are necessarily different. In the case of American aborigines, we have an arguably advanced stone age culture living concurrently with more modern cultures. This provides an opportunity to infer historical anthropological ideas from the study of a living culture.

Re: Moons of Jupiter (7/14/09)

by Chris Peterson » Thu Jul 23, 2009 7:10 pm

rstevenson wrote:A) My remark was intended as light humour, and not to be taken too seriously.
I know.
B) Nevertheless, I imagine that anthropologists would take considerable exception to your assessment of their experience and knowledge. Surely, as an astronomer with an interest in archaeoastronomy, you can at least accept as a possibility an anthropologist with an interest, indeed a specialty, in early cultures. After all, if they are to understand modern cultures via observation, they need some sort of baseline data.
Some might. However, as a science, anthropology is really not on the same level as astronomy. In many respects, it isn't science at all. I gave a talk at an archaeology conference a few years ago, comparing astronomy and archaeology in an explanation of why archaeologists have a hard time dealing with archaeoastronomy. The main point was that archaeologists aren't really scientists. It didn't seem to offend many: my paper is still used in a University of Arizona archaeology class, and I received many positive comments from archaeologists over the course of the conference. Anthropology, like archaeology, is mainly a social science, and honest social scientists realize that the "science" they practice is rarely that.

That's not to say that an anthropologist can't specialize in early cultures, but the fact remains, almost everything about prehistorical cultures remains extremely speculative. You only have to look at the widely conflicting opinions that are published whenever some new artifact is discovered.

Re: Moons of Jupiter (7/14/09)

by The Code » Thu Jul 23, 2009 7:07 pm

rstevenson wrote:A) My remark was intended as light humour, and not to be taken too seriously.
I did not find the word Loco, very funny. sorry

Mark

Re: Moons of Jupiter (7/14/09)

by rstevenson » Thu Jul 23, 2009 6:57 pm

Chris Peterson wrote:
rstevenson wrote:Or consult an anthropologist.
Even that would be of questionable value, since anthropologists have no experience with several thousand year old cultures, and only the most limited data on modern primitive societies.
A) My remark was intended as light humour, and not to be taken too seriously.

B) Nevertheless, I imagine that anthropologists would take considerable exception to your assessment of their experience and knowledge. Surely, as an astronomer with an interest in archaeoastronomy, you can at least accept as a possibility an anthropologist with an interest, indeed a specialty, in early cultures. After all, if they are to understand modern cultures via observation, they need some sort of baseline data.

But enough off-topic chit chat. Back to the moons!

Rob

Re: Moons of Jupiter (7/14/09)

by Chris Peterson » Thu Jul 23, 2009 6:27 pm

rstevenson wrote:Or consult an anthropologist.
Even that would be of questionable value, since anthropologists have no experience with several thousand year old cultures, and only the most limited data on modern primitive societies.

Re: Moons of Jupiter (7/14/09)

by rstevenson » Thu Jul 23, 2009 6:15 pm

Chris Peterson wrote:... We'll probably just have to agree to disagree.
Or consult an anthropologist. But then, if an anthropologist were lurking here, they wouldn't want to contaminate their research by actually communicating with their subjects. :P

(Hmmmm, maybe that's why loco has gone silent.)

Rob

Re: Moons of Jupiter (7/14/09)

by Chris Peterson » Thu Jul 23, 2009 4:28 pm

neufer wrote:People took note of the sun & moon (and, on occasion, the planets) and were temporarily scared of eclipses & comets (and, on occasion, supernova) but their culture (like ours today) concentrated heavily on active local things like humans, animals, plants, floods, etc. . Astronomy has almost always been a quaint sideline interest for a few folks with spare time or their hands.
I don't think we can say with certainty just how strong a role the sky played in most ancient cultures. This discussion came from your earlier assertion:
neufer wrote:I think it fair to say that man had little spare time to contemplate the heavens until he developed agriculture.
A relatively unchanging sky was basically ignored by both men & other animals because it posed no threat & provided little benefit.
I think that is inaccurate. I think that people certainly had time to contemplate the sky, and that they had motivation to do so. Survival depended on as complete an understanding of nature and their environment as they could develop. The patterns in the sky, and in the movement of the sky, would have had both practical (calendrical, hunting, gathering) uses, and also astrological uses (which all cultures seem to have perceived as practical).

For most ancient cultures, we'll probably never know for sure. So this comes down to our individual assessment of how societies, and human psychology, work. We'll probably just have to agree to disagree.

Re: Moons of Jupiter (7/14/09)

by The Code » Thu Jul 23, 2009 4:18 pm

neufer wrote:but their culture (like ours today) concentrated heavily on active local things like humans, animals, plants, floods, etc. . Astronomy has almost always been a quaint sideline interest for a few folks with spare time or their hands.
http://www.channel4.com/history/microsi ... nca3b.html

Not if there hole lives were encapsulated in the heavenly bodies?

Mark

Re: Moons of Jupiter (7/14/09)

by neufer » Thu Jul 23, 2009 4:05 pm

Chris Peterson wrote:
neufer wrote:If they were common the first known star map would be older than a mere 14 centuries.
I don't think so. Ancient cultures, for the most part, recorded very little. Most didn't even have mechanisms for recording things.

My own readings in archaeoastronomy (which are extensive) lead me to the conclusion that fascination with the night sky is an inherent property of being human (like engineering, or creating art). I think it is found in all peoples and all cultures, and probably has been for tens of thousands of years. I think that cultures that didn't identify and define constellations, create star-based mythology, make note of monthly and seasonal changes, and of unexpected events (eclipses, comets, meteors) must have been rare, or even non-existent.
People took note of the sun & moon (and, on occasion, the planets) and were temporarily scared of eclipses & comets (and, on occasion, supernova) but their culture (like ours today) concentrated heavily on active local things like humans, animals, plants, floods, etc. . Astronomy has almost always been a quaint sideline interest for a few folks with spare time or their hands.

Re: Moons of Jupiter (7/14/09)

by Chris Peterson » Thu Jul 23, 2009 3:59 pm

mark swain wrote:You may wanna look up your first known star map... Its a Tad older than you think...
It's a bit tricky, because it depends on how you define "star map". There are unambiguous and reasonably accurate maps of the night sky dating back more than 2000 years in both China and Egypt. There is at least one unambiguous but marginally accurate map dating back 3500 years to Bronze Age Germany. And there are ambiguous artifacts with possible astronomical significance dating back more than 30,000 years, also in Europe. There are references to the stars and astronomical events dating back as far as we have written records.

Re: Moons of Jupiter (7/14/09)

by The Code » Thu Jul 23, 2009 3:38 pm

neufer wrote:If they were common the first known star map would be older than a mere 14 centuries.

You may wanna look up your first known star map... Its a Tad older than you think... :wink:

Re: Moons of Jupiter (7/14/09)

by Chris Peterson » Thu Jul 23, 2009 3:09 pm

neufer wrote:If they were common the first known star map would be older than a mere 14 centuries.
I don't think so. Ancient cultures, for the most part, recorded very little. Most didn't even have mechanisms for recording things.

My own readings in archaeoastronomy (which are extensive) lead me to the conclusion that fascination with the night sky is an inherent property of being human (like engineering, or creating art). I think it is found in all peoples and all cultures, and probably has been for tens of thousands of years. I think that cultures that didn't identify and define constellations, create star-based mythology, make note of monthly and seasonal changes, and of unexpected events (eclipses, comets, meteors) must have been rare, or even non-existent.

Re: Moons of Jupiter (7/14/09)

by neufer » Thu Jul 23, 2009 2:24 pm

Chris Peterson wrote:
neufer wrote:Well, then, there are 20th century anthropological studies of existing primitive hunter gatherer tribes. Except for the Dogons (who basically assimilated outside astronomical culture) there really isn't a lot of astronomy or astrology there. Nighttime was simply too dangerous to be outside much...
Which tribes? There is a rich record of cultures with astronomical traditions: Inuit (hunter), Polynesians (semi-agricultural and hunter-gatherer), North American Indian (semi-agricultural and hunter-gatherer), Central American Indian (agricultural, but with limited seasonal influence), Australian Aboriginal (hunter-gatherer), and others. You should not dismiss the Dogon people's (agricultural, with limited seasonal influence) astronomy, either. Their astronomical mythology predates European or Islamic contact; it is the very existence of that mythology that resulted in their eagerness to appropriate outside knowledge and incorporate it into that belief system.
"Rich" record...compared to WHAT?

Every society has a few nerds like us that are interested astronomy. :wink:

If they were common the first known star map would be older than a mere 14 centuries.

Re: Moons of Jupiter (7/14/09)

by Chris Peterson » Thu Jul 23, 2009 2:12 pm

neufer wrote:Well, then, there are 20th century anthropological studies of existing primitive hunter gatherer tribes. Except for the Dogons (who basically assimilated outside astronomical culture) there really isn't a lot of astronomy or astrology there. Nighttime was simply too dangerous to be outside much...
Which tribes? There is a rich record of cultures with astronomical traditions: Inuit (hunter), Polynesians (semi-agricultural and hunter-gatherer), North American Indian (semi-agricultural and hunter-gatherer), Central American Indian (agricultural, but with limited seasonal influence), Australian Aboriginal (hunter-gatherer), and others. You should not dismiss the Dogon people's (agricultural, with limited seasonal influence) astronomy, either. Their astronomical mythology predates European or Islamic contact; it is the very existence of that mythology that resulted in their eagerness to appropriate outside knowledge and incorporate it into that belief system.

Re: Moons of Jupiter (7/14/09)

by neufer » Thu Jul 23, 2009 11:28 am

Chris Peterson wrote:
neufer wrote:I don't see any indication of it in any cave painting.
While there is some rock art that may have astronomical significance, I don't think it really matters. Rock art pretty clearly represents only a few ancient cultures (using the term loosely), and within them, only a fraction of their cultural content (we don't see much in the way of tools, for instance). Neither do we see much that could be interpreted as spiritual or religious, even though there is good evidence that very ancient cultures had something like religious practices.

I don't find the absence of astronomical imagery in cave paintings to be a very convincing argument against ancient people having astronomical knowledge, and astrological beliefs.
Well, then, there are 20th century anthropological studies of existing primitive hunter gatherer tribes. Except for the Dogons (who basically assimilated outside astronomical culture) there really isn't a lot of astronomy or astrology there. Nighttime was simply too dangerous to be outside much; especially when there was sex, drugs, sleep and somewhat more instructive stories about animals to be had safely with shelters (including caves & igloos). Even early agriculture was more conducive to Frazer's _Golden Bough_ vegetative-god children of the corn type stories than to star lore.

As Joseph Campbell says: "people aren't interested in learning the meaning of life; rather they are interested in feeling alive." Plants, animals & other humans were all alive; the sky, for all it's beauty, was almost dead. Even modern man prefers to watch reality shows & sitcoms to watching NOVA.

Re: Moons of Jupiter (7/14/09)

by Chris Peterson » Thu Jul 23, 2009 5:44 am

neufer wrote:I don't see any indication of it in any cave painting.
While there is some rock art that may have astronomical significance, I don't think it really matters. Rock art pretty clearly represents only a few ancient cultures (using the term loosely), and within them, only a fraction of their cultural content (we don't see much in the way of tools, for instance). Neither do we see much that could be interpreted as spiritual or religious, even though there is good evidence that very ancient cultures had something like religious practices.

I don't find the absence of astronomical imagery in cave paintings to be a very convincing argument against ancient people having astronomical knowledge, and astrological beliefs.

Re: Moons of Jupiter (7/14/09)

by neufer » Thu Jul 23, 2009 5:23 am

Chris Peterson wrote:
neufer wrote:I think it fair to say that man had little spare time to contemplate the heavens until he developed agriculture.
A relatively unchanging sky was basically ignored by both men & other animals because it posed no threat & provided little benefit.
I don't think that's a fair assumption at all. Even pre-agricultural societies must have found benefit in recognizing seasonal patterns. And from a purely spiritual standpoint, it's hard to believe that solstices went unrecognized, nor the connection between lunar cycles and fertility. I'd be very surprised if very early man didn't study the night sky, and know it well.
I don't see any indication of it in any cave painting.

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