In the web document at http://www.mindspring.com/~kftrans/SN1054.htm I argue that the supernova of 1054 AD (SN1054) could have produced enough cosmic dust to trigger the Little Ice Age, with this dust arriving on Earth approximately 200 years after the supernova was first observed.
I have heard similar ideas before. I have no idea if it is possible or not. But I was under the impression these little ice ages have come at rather regular intervals. Which would mean we get hit by space crap at regular intervals, and with regular amounts with regular effects. I wonder if, when people dig up core samples which tell them about these little ice ages, do they find materials suspected of coming from distant stars?
Randall This could be a nice topic to discuss, although I doubt there are people in the "Earth Science" forum that are versed in Astronomy and scientific methodology --at least to the extent as to mantain a reasonably coherent conversation. You see, this forum is full of people who believe in witches, blind sheeps and pregnant men in the Philipines... and their posts are more likely to be religious pamphlets or Apocalyptic prophecies than serious scientific disussions. Anyway, let's give it a try. Although I do quite nice in mineralogy, physics, chemistry, biology, climate sciences, etc, astronomy or cosmology are my weakest points. Also, I have to apologize for my English writing, spelling, grammar and syntax, as I am a Spanish speaking person, so I beg you to forgive some mistakes I will make in my posts. One thing I would like to ask you is to confirm is "kpc" (related to astral distances). Is this the English abbreviation of "<b>kilo parsec</b>" (parsec = per second) that is, "thousand-year-light", the distance traveled by light in one year? In that case, am I wrong if I say it should be abbreviated "<b>kps</b>" --kilo per second? Excuse my ignorance in this field, and please correct me if I am wrong. Then, although your theory seem feasible (and promising), I am not in possesion of the knowledge to even arguing with you about it. But, as my climatology studies gives me information on the field of warming, cooling, ice ages, etc, I would like to point you some facts. Of course, the only thing that affects the temperatures on Earth is the sun --and related matters as tilt of Earth's axis and precession of the Equinoxes, and, given that these things have not changed significantly for the last 10,000 years, we can say that if the Earth warms or cools is due to <b>only two things:</b> a) The sun gets brighter or dimmer (solar cycles, sunspots, flares, etc), or b) The atmosphere gets filled with some obstruction, as dust (either cosmic as in your theory, or coming from the impact of asteroids big enough to send billions of tons and water up into the stratosphere. We can dismiss the influence of "greenhouses" gases as CO2, methane, and other minor constituents of the atmosphere, because: 1) water vapor is the only major greenhouse gas (95% of heat retention capability), and 2) during the Cretaceus period (about 90 million years ago) concentrations of CO2 were in the order of 2,600 to 6,000 ppm, while global temperature was only 1,5°C higher than today. Greenhouse gases dissmised. The <b>Medieval Warm Period</b> reached its highest point around the year 1200 AD, and about 1250 AD beagn a fast cooling. The line of the 15°C mean temperatures was crossed about 1350 AD, and kept going down until 1450 AD, when a slight warming was experienced. Around 1500 the world cooled quite fast until 1650 AD (when temperatures were at their lowest in the milennium). Then, a quite fast warming ocurred until 1700, and then, temperatures kept almost steady until 1860. From then on, temperatures have been returnig to the values they had back in 1200 AD --<b>but we still are 2°C below</b> those temperatures. The arrival of "cosmic dust" from the Crab around 1250 could have helped to trigger the <b>Little Ice Age</b> (don´t let "global warming" environmentalists hear you say there was such an Age, because they will crucify you -- if you are researching with government funds you will lose your grants). I said <i>"it would help trigger"</i> the Ice Age because between the years 1300 AD and 1500 AD there happened the <b>"Spoerer Minimum"</b> cool period, when the absence of sunspots was almost total. When the effects of the "cosmic dust" was likely to have disappeared (the dust had settled) and tenperatures began to go up again, there came the "Maunder Minimum" period of no sunspots, that lasted from 1640 AD to 1710 AD, when there were no sunspots at all. The sun had a period of absolute calm during those years, so the Earth cooled again. As the sunspot record began about the 1600s, what happened with solar activity remains a mystery --only partially solved (or attempted to solve) by "proxy" studies. By 1715, the solar activity became "normal" again, and Earth started to warm until these days. I quoted "normal", because the <b>only normal thing</b> known in Earth's history is precisaley <b>the changes that characterizes Earth geological and climatic record</b>. Summing up: If the dust from the supernova reached Earth, it could have helped trigger the Little Ice Age, but the major "responsability" --in my humble opinion-- lies in the Spoerer Minimum, because when 150 years later the Maunder Minimum came along, it happend the same thing (and worse, because it cooled much more), while the effect of the cosmic dust must have disappeared by then. The eruption of Tambora volcano set the world into a two-year "summerless" period, back in 1816 (even Ben Franklin wrote about it, blaming the weird weather on the Tambora). Given that the amount of dust received from space might have been greater than Tambora's ouput, I would accept that it could have cooled (or helped to cool faster) the world. But the dust and debris from Tambora have settled down after two years, so the dust from the Crab could not last much longer. How much? Ten years? Who knows? But if there was enough dust to provoke such severe cooling, I suppose that must have been noticed by the people all over the world, and there would be written or oral accounts of an event so big that set Earth into a glacial age. If there are accounts of the vikings colonizing Greenland and Canada by the same time, then why are not there accounts of this cataclismic event? Or perhap´s there are? Or perhaps it went unnoticed down here at the surface, and everything happened up there, as you say: <i>"... two things would happen: pressure from sunlight would direct it away from the Sun, and collisions of the dust particles with solar photons would cause the particles to lose energy and transverse momentum. Some of the particles would end up spiraling into the Sun. But some of them would end up orbiting it. As the dust approached the Earth (some of the dust would be captured in an orbit just outside the Earth's), it would be perturbed by the Earth's gravity, and some of the particles would be sucked in."</i> Could it be that the effects of the supernova <b>affected also the sun's activity and provoked the Spoerer Minimum?</b> Could be, why not? But then, what provoked the Maunder Minimum? Another supernova explosion? That show us there is too much we ignore about almost everything. And that makes life enjoyable: <b>the quest for knowledge.</b> Let's keep with this topic. We might not end up earning lots of money, but we might end up "saving the planet"... whales, mosquitoes and butterflies included. Please Register or Log in to view the hidden image!
Ooops! I don't know why, but my message was posted twice. I just edited it and the thing has been fixed.
Still here... Randall: if you go to this link, and go down the page to a title saying: <b>A Crack in the `Hockey Stick' (23 March 2002)"</b> you'll find some information on the Little Ice Age and the solar activity for those times. Follow the links in the article and see what is all about. <A HREF="http://www.john-daly.com/"><b>"Still Waiting for the Greenhouse"</b></A> or go directly to the main article: <A HREF="http://www.john-daly.com/hockey/hockey.htm"><b>"The Hockey Stick"</b></A> Hope you'll find the articles interesting. I did.
Welcome to Sciforums, Randall. Very interesting paper. Pardon...this may be a stupid question....yet I can only cross my fingers and hope Chaggie dosen't strart bickering over it.... If the earth was being affected by such 'dust', we would find a geologic layer for that time period containing rare elements that we would expect from supernova 'dust', correct? Also, perhaps I am being dense, but I do not see how this cosmic 'dust' would cause an ice age. By blocking out sunlight? That does not seem right at all.... Edufer: kps is 'kilo parsecs'.
Tephra or cosmic dust? Edefer wrote: "But if there was enough dust to provoke such severe cooling, I suppose that must have been noticed by the people all over the world, and there would be written or oral accounts of an event so big that set Earth into a glacial age. If there are accounts of the vikings colonizing Greenland and Canada by the same time, then why are not there accounts of this cataclismic event? Or perhap´s there are? Or perhaps it went unnoticed down here at the surface, and everything happened up there. . ." Actually, the model that I propose does not require the arrival of an overwhelmingly large amount of cosmic dust on earth--although it doesn't exclude that possibility either. As I pointed out in the referenced paper, the Little Ice Age could have been triggered by a very small amount of dust assuming that Muller's notion that climatic change is linear is correct. However, it also seems worth pointing out that what has been interpreted as the world's largest volcanic eruption of the past millennium occurred in 1258 AD, and this event was accompanied by a massive atmospheric aerosol that eventually blanketed the globe. Samples of sulfur-based debris have been retrieved from dated ice cores in Greenland, the Canadian Arctic and Antarctica. One problem with the volcanic interpretation of this event is that the source volcano has never been found (although some have concluded it was Mexico's El Chichon volcano). Further details may be found in R. B. Strothers, Climatic Change 45, 361-374 (2000); abstract at http://www.giss.nasa.gov/gpol/abstracts/2000/Stothers1.html. I'll have to address the other concerns separately.
Accretion models of climatic change Xev wrote: "Also, perhaps I am being dense, but I do not see how this cosmic 'dust' would cause an ice age. By blocking out sunlight? That does not seem right at all...." Without committing to any one in particular, let me mention that accretion models of climatic change come in a variety of flavors. In the scattering of sunlight model, light is blocked from the earth so cannot warm it. But, as you point out, interplanetary dust would not ordinarily arrive in sufficient quantities to directly scatter sunlight. In the cloud cover model, the dust modulates the formation of clouds by altering the electrical conductivity in the atmosphere. Since the dust absorbs free charges, it thereby affects cloud cover. There are a couple of other accretion models worth mentioning, the noctilucent model (in which dust acts as nucleation sites for water vapor in clouds about 90km high) and the ozone model (in which the dust alters the tropopause via ozone effects). For further details see R.A. Muller, Ice Ages and Astronomical Causes, Springer, 2000. Note: The citation for Stothers in my last posting was garbled. Should have been: http://www.giss.nasa.gov/gpol/abstracts/2000/Stothers1.html ". . . and to dust thou shalt return." Genesis 3:19
Xev <b>quote: </b><i>"Edufer: kps is 'kilo parsecs'."</i> That's what I wrote, as I knew it as "kps". In Randall's paper it appears as "kpc" so I wanted to know if "kpc" and "kps" were the same thing. Thanks anyway, Xev.
Yum! Randall: Okay, I see..... Now, what sort of things would you expect to see if your theory is correct? I mentioned rare elements......can you think of anything else?
I have read this thread with particular interest but have not yet read the attached links. Rest assured that I will. I would think that if this model that predicts dust caused a drop in sunlight arriving on earth through diminishing intensity that the decrease in sunlight would have been noticed. Noticed by farmers, whose crops would not be as robust (of course this might be taken as the drop in temperature caused the change). It should also have been noticed by those spending a large amount of time outside most of their lives. The first thing that comes to mind is that the temperature drop would corrospond to the density of the amount dust present. (i.e. the thicker the dust the more sunlight blocked) Through some of the articles that have come to light in the astromony section, it is believed that some of the amino acids, pah's, ect could survive a trip through the atmosphere to the surface of the earth. Also it has been suggested through the same type of articles that a "rain" occurs almost all the time of particles floating down from space to the surface. This should mean that there should be some type of presence to be detected on the earth itself. One of the problems I have with this is that this dust cloud would have to fight the light pressure from our solar wind and stay intact (not dissapate) to effect this change. That the dust would have to be persistant and remain in system to continue the effect. Given that the velocity of said dust cloud would moving at a good clip, it would seem that there would have to be a massive amount. In the planetery nebula that I like to post pic's of, most of the time, these clouds are present for 1000's of years. It is hard to accept that we "got lucky" and only got a 10 year brush with this cloud. Maybe I don't see the whole big picture yet and the articles will help make this clear...
Orignally Posted By Edufer "We can dismiss the influence of "greenhouses" gases as CO2, methane, and other minor constituents of the atmosphere, because: 1) water vapor is the only major greenhouse gas (95% of heat retention capability), and 2) during the Cretaceus period (about 90 million years ago) concentrations of CO2 were in the order of 2,600 to 6,000 ppm, while global temperature was only 1,5°C higher than today. Greenhouse gases dissmised. " How can you dismiss the influence of those gases? They have been proved to be greenhouse gases. And 1-5 degress C is a big change. 1-5C can melt the polar icecaps. 1-5C can dramatically change the eniviroment of the planet. Later T P.S. your english is Excellent. Probably better than mine and I am an American!Please Register or Log in to view the hidden image!
Tristan What they have proved is that water vapor (humidity in the aire) accounts for 95% of the heat retention capability of the Earth, while CO2 accounts just for 3,5%. Just look at this: The Amazon jungle is about the same latitude of the Sahara desert, and both places have the same levels of CO2. But temperatures in Hoggart (in the sahara) are: Maximum: 50°C, Minimum: -5°C. That means there is a wide temperature amplitude: 55°C. The relative humidity of the Sahara barely reaches 5%. At the same time, in the jungles maximum temperatures are about 32°C (during rainy seasons = high humidity, about 90%), and the lows are about 23°C. The amplitude is about 9 - 10°C. This means that the heat was retained during the night in the jungles, and the heat was radiated back to space in the Sahara. So who was responsible for keeping the heat in the atmosphere?: the 90% humidity of the jungles, as levels of both the jungles and the Sahara are the same: 360 ppm. Besides, the concentrations of CO2 during the Cretaceus period (60-90 million years ago) were between 2,600 and 6,000 ppm, while the temperatures at the same time were 1,5°C higher than today --but still 2°C lower than those occurring during the Climatic Optimum (or Medieval Warm Period) about 800-1250 AD, when CO2 levels were about 300 ppm. About polar ice caps: they have not been melting (no evidence of such thing in the Arctic sea), while the ice caps in Antarctica have been growing at fantastic rates, provoking the breakdown of the Larsen ice barrier, a couple of months ago.
Whoa whoa whoa! I don't want this to end up as yet another discussion of global warming..... Wet1: Good point. I also see a problem in that, well, there would have to have been an awfull lot of dust to block sunlight..... When a volcano erupts, the particles are 'trapped' on earth due to the atmosphere, correct? But in space, they would have been relativly 'free' to move around.... I think we can rule out the theory that light was 'blocked' from the earth. Now, onto the cloud cover being affected theory..... I think (I may be wrong, of course) that the amount of rain would have been affected by this..... But I do not see in the records that I have read that the amount of rain we recieved changed... http://www.vehiclechoice.org/climate/cutler.html http://www.grisda.org/origins/10051.htm
I would think that volcanic clouds would change rainfall, also -- unless the type of cooling that takes place following this, inhibits precipitation in some way. Haven't found anything yet...
