Skip to comments.Ice ages linked to earth's travels through galaxy
Posted on 08/02/2005 4:00:39 PM PDT by Graybeard58
It might sound preposterous, like astrology, to suggest that galactic events help determine when North America is or isn't buried under immense sheets of ice taller than skyscrapers. But new research suggests the coming and going of major ice ages might result partly from our solar system's passage through immense, snakelike clouds of exploding stars in the Milky Way galaxy.
Resembling the curved contrails of a whirling Fourth of July pinwheel, the Milky Way's spiral arms are clouds of stars rich in supernovas, or exploding stars. Supernovas emit showers of charged particles called cosmic rays.
Theorists have proposed that when our solar system passes through a spiral arm, the cosmic rays fall to Earth and knock electrons off atoms in the atmosphere, making them electrically charged, or ionized. Since opposite electrical charges attract each other, the positively charged ionized particles attract the negatively charged portion of water vapor, thus forming large droplets in the form of low-lying clouds. In turn, the clouds cool the climate and trigger an ice age -- or so theorists suggest.
In that regard, researchers are finding correlations between the timing of Earth's ice ages and epochs when our solar system passed through galactic spiral arms.
The latest evidence appears in a recent issue of Astrophysical Journal. The article is the result of an unusual collaboration between an astronomer, Professor Douglas Gies of Georgia State University's Center for High Angular Resolution Astronomy, and a 16-year-old student at Grady High School in Atlanta, John Helsel. They report the results of their effort to determine how the sun has moved through the galaxy over the last half-billion years.
By making a variety of assumptions about the rate of solar motion and the distribution of spiral arms in the galaxy -- which are difficult to map because galactic dust and foreground stars get in the way -- Gies and Helsel conclude that "the sun has traversed four spiral arms at times that appear to correspond well with long-duration cold periods on Earth."
"This," they continue, "supports the idea that extended exposure to the higher cosmic-ray flux associated with spiral arms can lead to increased cloud cover and long ice age epochs on Earth."
Gies and Helsel's article is the long-term result of a project that Helsel began working on "as a science fair project," Gies says. Gies, 50, is a neighbor of Helsel's. Gies had previously "developed a scheme to model the motion of some massive stars in the galaxy," and when Helsel approached him for guidance on the science fair project, their "conversation quickly focused on studying the sun's motion and encounters with spiral arms in the galaxy."
A veteran investigator of the galaxy-ice age hypothesis is astrophysicist and assistant professor Nir Shaviv, 33, of Racah Institute of Physics at Hebrew University in Jerusalem, who was previously a postdoctoral researcher at the California Institute of Technology. He has reanalyzed other scientists' previously published data on meteorites, which contain mildly radioactive isotopes -- fragments of atoms that were altered by cosmic-ray bombardments over millions of years while the meteorite was still hurtling through space. Based on the ages of different isotopes, he concludes the cosmic-ray bombardments were most intense during past epochs when Earth is believed to have passed through known spiral arms.
An alternate but related hypothesis of ice ages suggests that Earth occasionally passes through huge interstellar clouds of hydrogen gas. Such clouds are common in the spiral arms. According to this hypothesis, the interstellar clouds chemically soak up oxygen molecules in Earth's atmosphere, dramatically lowering the levels of the gas ozone, which normally heats the atmosphere by trapping infrared radiation.
Let me be the first:
Still, Bush's fault.
Sounds a little bit like Velikovsky's theory, which mainstream science would never admit.
It just goes to show that there are so many little understood processes going on that we can't make a firm determination.
I assume you do.
Too much reading for now. But thanks for the link.
sounds more like the GOD theory too me, also something mainstream science would never admit
It's one of those interdisciplinary theories that only experts can parse successfully. I read through Carl Sagan's critique of Velikovsky, and I have my doubts about both sides. Just this week, cosmology has been turned on its head because the comet that had a probe smash into it turned out not to be a big ball of ice. Some of Velikovsky's predictions proved to be true, but I think most of it has been debunked.
I think it's possible the Russians were keenly interested in Velikovsky, which is why they sent so many probes to Venus rather than Mars.
This particular side of Velikovsky had to do with his theory that Noah's flood was caused by the earth going through the tail of a comet and all the water precipitation that resulted, which is probably not the case.
All I can say is, I'm fascinated. The more I read, the more I learn. And I prefer to pick up both sides of a controversy before I come to any conclusions. Since I'm not a geologist nor cosmologist, it takes me longer.
I'm not scientist, but I've read enough rebuttal material because of my initial interest in his publications to now think that he was wrong.
Nothing wrong in floating new ideas. Einstein surely did. But let them sink or float based on their merits.
And largely, I think that is what has happened.
Yep. It was more than 30 years ago that I heard his theory, my dad read the book. One thing I appreciated about it was that it opened my mind at an early age. But there is enough hokiness in the theory for it to be discarded, mostly.
Some of his stuff is VERY intriguing, though. For instance, I think he was the first to point out that all the ancient calendars had 360 days. His premise was that it wasn't that they couldn't count but that the earth took 360 days to revolve around the sun at the time. I wonder if he was onto something. So I keep my ears tuned to stuff that might have bearing in his theory and keep mulling it over...
When I look at both sides of Van Danniken's theory, I see he was pretty full of horse manure. There was a great video that rips his theory to shreds, I can't remember the name of it.
Since I was the one who posted the original comment, I'll presume you intended your response for me.
The GOD stuff is something I have spent considerable time investigating, and it is completely different because one can come to a conclusion without being an expert.
The best book I read on the subject was "Jesus: God, Ghost or Guru?" by Buell & Hyder. It's out of print. I guess the best alternative would be "The Case for Christ" by Strobel.
There is a growing number of scientists who see evidence of a creator in our creation, and many have accepted Christ. When I look through the creation/evolution/abiogenesis threads, it's easy to see that Scientism is just another religion, albeit a rather sophisticated one.
Let me be the first.
"16-year-old student at Grady High School in Atlanta, John Helsel"
16 years old???????????
I TOLD it not to travel through the galaxy....but did it listen.....????
16 years old
Let me be the first to suggest that this kid is wasting his time in high school.
We have been discussing ways to fast track kids through high school to avoid the liberal agenda and other idiocies:
Unfortunately my thread title was not well thought out, because some parents might instinctively skip over it due to attached stigma, whether real or imagined.
jesus - god ghost or guru is available used on amazon and i would guess other places.
following your reco, I've ordered a paper copy for $7
cs lewis wrote about this also. I guess its a common topic.
Please FREEPMAIL me if you want on, off, or alter the "Gods, Graves, Glyphs" PING list --
Archaeology/Anthropology/Ancient Cultures/Artifacts/Antiquities, etc.
The GGG Digest -- Gods, Graves, Glyphs (alpha order)
I've heard this hypothesis proposed in the past. Interesting.
I guess the bacteria theory about the cause of the Ice Ages posted yesterday is 'out' already, huh?
I missed it?
Not sure what casues them but I'm convinced that SUVs got us out of the last one.
No, it doesn't sound anything like Velikovsky.
The theory that spiral arms in the galaxy affect climate is "the God theory" exactly how?
Ice age ping...
Thanks for this, but I would suggest also that one looks here:
The Pacemaker of the Ice Ages: Milankovich Cycles in Climate
The changes in ice volume were cyclical, with a rather complex periodicity. Such a periodicity can be produced by adding up three wave functions, which a wavelength of about 100,000, 41,000 and 23,000-19,000 years (as in adding up the wave functions in biorhythm analysis). These waves represent increases and decreases in solar energy as seen at a specific location on Earth.
The three periodicities are well-known to astronomers, because they describe irregularities in the pattern of the Earth's motion around the Sun (and are therefore called orbital parameters). These irregularities are caused by the gravitational effects of the other planets circling the Sun.
Such irregularities cause fluctuations not in how much solar energy is received by the whole Earth, but in how much solar energy is received at a specific latitude on Earth, or in the distribution of solar energy by latitude and by season. The three periodicities are commonly called Milankovich periodicities, after the Serbian mathematician who calculated them in the 1930s, and thought they might have caused ice ages, by causing small differences in the amount of solar energy (insolation) that reaches the Earth at the high latitudes where the ice sheets form. The idea behind this theory is that in order to form a large ice sheet much snow must accumulate in the winter, which can not melt in the summer. If we thus have a fairly cool summer, but not too cold a winter, ice sheets can be expected to grow. Winter should not be too cold, because at very low temperatures the atmosphere can not contain much water vapor, so that no snow can fall.
First, we have to know how the Earth moves around the Sun, in its elliptical orbit. The earth's axis is inclined and not at right angles with the plane through the orbit. This inclination (about 23.5o) results in the seasons: the southern hemisphere is tiled towards the Sun during its summer which occurs during northern hemisphere winter, and the reverse. Days are longer, nights shorter on the hemisphere that is turned towards the Sun. Twice a year, in the equinoxes, day and night have the same length. During the northern hemisphere winter solstice, the shortest day occurs on the northern hemisphere and the longest day on the southern hemisphere; during the northern hemisphere summer solstice the day is longest on the northern hemisphere, shortest on the southern hemisphere. This regular patterns of motion, however, is changed because of the disturbance of gravity of the Earth by the presence of the other planets.
The three orbital parameters are:
* Variation in excentricity, or ellipticity of the Earth's orbit; periodicity about 100,000 years. The shape of the Earth's orbit around the Sun varies, from an almost exact circle (ellipticity 0) to a slightly elongated shape (eccentricity 0.06). The eccentricity influences seasonal differences: when the earth is closest to the Sun, it gets more solar radiation. If that occurs during the winter, the winter is less severe. If a hemisphere has its summer while closest to the Sun, summers are relatively warm. Nowadays, the Earth is closest to the Sun in the northern hemisphere winter (causing relatively warm winters), furthest from the Sun in northern hemisphere summer (causing relatively cool summers). Note below that excentricity and precession both influence the character of the seasons.
* Variation in obliquity, i.e., the tilt of the Earth's axis away from the orbital plane. Periodicity 41,000 years. The tilt varies between 22 and 25o, and is on average about 23.5o. Note that obliquity describes the tilt of the Earth's axis, but not its direction of tilt. At higher tilts, the seasonality at high latitudes becomes more extreme; changes in tilt have little effect in the tropics, maximum effect at the poles.
* Precession of the equinoxes, periodicities of about 23,000 and 19,000 years. Precession is a rather complex phenomenon, which is caused by two factors: a wobble of the Earth's axis, and a turning-around of the elliptical orbit of the Earth itself. Note that the precession affects the direction of the earth's axis, not its tilt. The combined and complex wobbly motion of the Earth has the following result: the equinoxes (days of equal length of night and day) do not keep occurring during the same day of the calendar, but slowly shift. Presently, the Earth is closest to the Sun in the northern hemisphere winter, which makes the winter there less severe. In about 11,000 years in the future the Earth will be closest to the Sun in the northern hemisphere summer, making northern hemisphere summers warmer, winters colder. The precession effect thus causes warm winters and cool summers in one hemisphere, while doing the opposite across the equator.
The Milankovich theory states that ice caps at the poles increased and decreased in size as a reflection of the solar energy received at fairly high latitudes; the insolation at 65oN is commonly used to look at the waxing and waning of ice sheets. For a nice computer visualization of how insolation changed over the northern hemispheric polar region, click here.
We have now observed in very many different records that ice volume over the last few millions years indeed waxes and wanes on the time scales of irregularities in the Earth's orbit, and that the northern hemispheric insolation, not the insolation of the southern hemisphere, appears to drive the process. For instance, we now have relatively warm winters on the northern hemisphere (because these winters occur when the earth is close to the Sun), and our winters are colder because we arecfar away from the sun when our side of the planet is tilted away from the Sun.
The fact that the history of ice volume occurred at these orbital frequencies implicates the differences in insolation in triggering ice ages, but very many questions remain.
* The orbital fluctuations can not be the whole story: over large parts of Earth's history there were no ice sheets, and the orbital character of the Earth fluctuated in the same way. We have indeed ample evidence of climate fluctuations on Earth at times that the ice sheets were much smaller than today's ice sheets, or even absent, at Milankovich periodicities. Then why did these fluctuations not cause ice ages during these earlier periods of Earth history?
* There have been changes over time in which one of the three orbital fluctuations had the dominant effect. For the last 900 to 1200 thousand years the excentricity has been dominant, before that the 40 thousand year obliquity was dominant. Why did this dominance change?
* From the climate theoretical point of view, the differences in solar heat received are very small, much too small to explain the large differences in climate. These differences largely relate to the distribution of energy over the Earth, but we have evidence that global temperatures changed during the ice ages. We therefore think that one or more positive feedback mechanisms must have enhanced the Milankovich differences in temperature.
* One possible enhancer is the amount of CO2 in the atmosphere, which fluctuated at the same periodicity as the ice volume, and was less by about 90 ppm (parts per million) during glacial periods, as we will discuss next week. But which was cause, which was effect?
* Other possibilities include the position of the continents: since the last few million years the northern hemispheric ice sheets grew and became smaller, and they had large continents where they could spread out. But the Antarctic ice sheet has covered the Antarctic continent and shallow seas, and can not easily grow by much.
We are therefore not sure of the exact causes of the ice ages. Milankovich differences in insolation were the trigger (Well DUH!), but many other feedback mechanisms probably operated. Some simple ones are:
1. positive feedback. When ice caps are larger, a larger surface area of the earth is white, and reflect back much heat from the sun into space, cooling down earth further, leading to enlarge ice caps, etc.
2. positive feedback. When ocean water cools, it can dissolved more CO2 (a gas), and thus takes up more CO2, leading to more cooling, etc.
3. negative feedback. When sea level drops, we get more land, less ocean surface. Vegetated land reflects less solar heat into space than ocean, so lower sea levels may lead to warming. When ice caps grow, sea level drops.
4. negative feedback. When ocean waters cool, less water evaporates; that means less precipitation world wide, which means lesser ice caps (made up of snow), see further point 1.
The complexity of perceived climate change in glacial-interglacial times is increasing rapidly with more and more knowledge. A more detailed knowledge of the way in which the ocean-atmosphere system works, and of the role of the biosphere in shaping climate (by its effects on the carbon cycle) is needed before we can begin to understand even this latest, best-known part of Earth history.
Measure of ice volume on Earth. Notice the increase of ice volume staring at about 3.0 Ma, and the increase in the amplitude as well as timing of the major climate swings at about 1.2 Ma.
Or maybe it's just a little bit of shade from the interstellar clouds.
I don't think that ALL of them had 360 days, but for many of the older cultures in the middle east (until finger-counters took over), base 12 was used, and by derivative, 60, and 360 were common units. 360 degrees in a circle, 360 days.
Oops, shouldn't have said all.
I guess I don't follow. Where does the 360 degrees in a circle come from again? How did these cultures attain base 12 counting? I haven't run into any explanations that make sense yet, perhaps you have.
If they could do something as sophisticated as count in base 12, surely they could count how many days in a year there were. Being off by 5 days/year means that within a short time, their seasons go out of whack and their harvest gets affected.
10 is only divisible by 5 and 2.
Oh, and many older calendars had an "extra" period, with 5 or 7 days, to adjust for this known difference.
Because of the easy math. Unlike 10, 12 is evenly divisible by 1,2,3,4,and 6. Several early societies went for base 60, for easy division by 1,2,3,4,5,6,10,12,20, and 30.
Learning 60 different characters for numbers was more trouble than it was worth, though...
Ummm, that too.
I think we should stop counting on our thumbs, and go to base 8 myself...
Thanks guys. It's something to think about. Perhaps a good modern parallel would be the metric system, which worked backwards from the circumference of the earth using a base10 approach. So it's conceivable that the powers that be at the time (King Sennacherib or some such) decided to standardize on a system that made the most sense at the time.
I still have trouble grasping it. If you guys are historians, this is the perfect place to start writing a new book. People are hungry for sensible answers to puzzling questions.
Issac Asimov wrote about things like this much better than I ever could!
Sounds like a reasonable 'theory'.
Thanks. Problem with uniformitarian causes is, that they aren't. :') That's why there are so many such models. Earth's closest to the Sun in January I think, which makes northern hemisphere winters a bit warmer, and furthest in July I think, making southern hemisphere winters a bit cooler. But most of the southern hemisphere is ocean, okay, I'm boring even myself...
"Let me be the first to suggest that this kid is wasting his time in high school. "
When I entered University I took an intensive first year mathematics progrom of first and second year courses becuase I had a high second class average in high school
In my second year linear class I struggled in the first two months of the fall semester and then one day this guy showed up in class who I hadn't seen before.
Turns out he was a math genius and the son of a mining engineer from Trail BC who had attented advanced mathematics camps since he was 13.
He showed up one day because he had an interesting proof he wanted to show the prof. When he was finished baffling the prof with his proof he left. Everyone in the class was slack jawed.
That day was the end of my mathematics career.
Later I found out he got bored with mathematics and joined the theater department.
I hope you find it as clear & well written as I did. I regularly pass out copies of that book, and I buy them from Amazon. Sorry about driving the price up.
Make sure you read the abstract before the book. It was so concise and on target, that I can show people that abstract and say, "This is what the book is about."
I have a mind to buy non-exclusive rights for that book. I wonder how much such a thing would cost?
Except for the drifting continents part.
The sun [and earth] rotate about the Milky Way in 200 million years. If there is a particular dusty spot in our spiral arm our inclination to the plane would swing us by that spot twice in 100 million years. That puts these events on the average 50 million years apart. Does that match up with the frequency of ice ages?
"Except for the drifting continents part."
***Actually, the tectonic plate theory is instructive here. Most scientists didn't accept that theory at the time it was proposed -- it was too outlandish. Eventually, those scientists died off and were replaced with a new generation of open-minded scientists who gave it a whirl and verified much of the theory. I see that a lot of catastrophism was summarily dismissed when it was first proposed by guys like Velikovsky, but now it is readily accepted as part of different cosmology theories.
"... any new theory (especially one which makes outstanding claims) has to have established scientific laws to support it."
***We both agree, sorta. I would readily accept your statement if the word "law" were substituted with the word "evidence". That word, "law" causes trouble in these kinds of discussions because people start using it as if it really did mean "law". In scientific method, a law is just an observation. Newton's law of gravity doesn't mean everything has to "obey" that law, it is just an observation of how gravity behaves, with a nifty mathematical description. Note that we do not call it the "theory of gravity" because a theory explains why... and we really don't know what causes gravity at this point. When physicists started noticing that at the atomic scale, Newtonian "laws" were no longer applicable, a new observation was introduced as a correction factor to physics, thanks to Einstein. It was widely discussed and supported because there were observations that no longer fit the Newtonian mold and, it was brilliant physics. Exactly what scientific "laws" did NOT support plate tectonics at the time it was proposed?
"I've read "Worlds in Collision" by Velikovsky and all of his physical predictions are invalidated by the well established laws of physics that I've studied up through college."
***I read it too, and I also studied somee physics in college, welcome to the club. Again I would quibble with your use of the word "law". I agree that Velikovsky's predictions and theory did not pan out for the most part. But his predictions were not invalidated by "laws" of physics, they were invalidated by direct empirical observation. Some people thought Velikovsky was ahead of the game when it was verified that Venus was indeed very hot (contemporary cosmology said that it would be a cold planet), but he was probably just lucky.
"Just as one example, his theory that Venus could pass by the Earth and cause the Earth's rotation to stop and then restart is nonsense according to the laws of thermodynamics and conservation of angular momentum, among others, and there are no known forces that could explain such an event."
***Again you're using the word "law" in a way that doesn't really help the discussion along. If I do the "law = observation" substitution, I would probably agree with you. The fact that there are no KNOWN forces which could explain it is exactly the point. It is postulated as an UNKNOWN force, possibly stronger than gravity, which is after all a relatively weak force. But that's one thing I like about bold theories -- they should be easy for experts to point out the obvious flaws. I'm no cosmologist.
Thanks for the ping.
I seriously doubt that earth CROSSES spiral arms of the galaxy, instead of drifting along with the flow that causes the spiral arms.
[Dewey McLean is one of the most stubborn opponents of the Alvarez model; he has mellowed somewhat in recent years regarding his claims that the late Luis Alvarez tried to run him out of academia]
New Developments Regarding the KT Event and Other Catastrophes in Earth History
Proposed law of nature linking impacts, plume volcanism, and Milankovitch cycles to terrestrial vertebrate mass extinctions via greenhouse-embryo death coupling
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