According to researchers who recently published an article, the change in the shape of the Milky Way as revealed by Spitzer's findings neutralizes the argument of Prof. Nir Shabiv from the Hebrew University who found a connection between climatic cycles and our crossing the galactic plane * Prof. Nir Shabiv: their calculations are incorrect
Earth's climate has changed throughout the geologic periods, but the reason for these changes is debated. One idea (Shabib Weiser, 2003), suggests that it is possible that two-thirds to three-quarters of the changes in the Earth's temperature in the last 500 million years, may have depended on the question of when the solar system crosses the plane of the spiral arm of the Milky Way in which it is located.
The evidence seems appropriate. It appears that there is a 140 million year cycle of global changes and that this coincides with the times when the sun crosses the spiral arm. Or so it was thought. Since 2003, the map of the galaxy as we know it has completely changed, which has caused a change in the estimation of when the Earth crosses the galactic plane.
"Although previous works found a correlation between the climatic cycle on Earth of 140 million years" write Adrian Mello, Andrew Oberholnt and Martin Paul, "the new data about the structure of the galaxy, cause this correlation to disappear." The cycle in question is the approximate cycle for the timing of ice ages and abundance of fossils. The basic idea of the researchers was that when the solar system crosses the plane of the spiral arm of the Milky Way, the rate of cosmic ray bombardment in the Earth's atmosphere is greatly increased, because the number of supernovae in the spiral arms is clearly greater than in the regions between the arms. This may lead to the creation of clouds on Earth and, therefore, to the strengthening of the greenhouse effect.
In 2003, it was assumed that the Milky Way had four arms, and that it was less massive than current calculations show. In 2008, information transmitted by the Spitzer Space Telescope helped astronomers determine that The Milky Way consists of two spiral arms and a large central bar. Additionally, in 2009, Spitzer's data helped scientists conclude that our galaxy is much more massive than previously thought, and that it is moving faster than previously estimated.
The question is, when did Earth cross the galactic plane? With the changes resulting from the higher mass estimate and the smaller number of arms, no one can be sure. However, Mello and his team compared the orbital periods of areas on the new galactic map with the changes in Earth's climate, and found that the 140 million year correlation is irrelevant. The team also says that the 140-million-year climate cycle does not match any of the solar system's periodic motions in the Milky Way.
The only temporal trend we can find with the new data is the orbital period of the solar system," the team writes in the article. "Relative to previous estimates, which predicted a pattern according to which the solar system accelerates in its orbit around the center of the galaxy, this cycle is somewhat greater than 500 million years, although it is possible to make some predictions about periodic trends through changes in the speed pattern of the structure of the arms, the period of the orbit relative to the pattern of the galaxy cannot In no case reach 140 million years, since this is less than the orbital period itself, and the meaning is that the stars in our spiral arm and the Sun circle the center of the galaxy in opposite directions.
Therefore, the researchers came to the conclusion that the passage of the solar system through the plane of the galaxy in the area of the arms could not directly affect climate changes on Earth.
Nir Shabiv's response: "Here are the reasons that explain why the argument of Melo and his colleagues is not even wrong.
- Mello estimates that there is only one speed pattern for the spiral structure, and therefore they do not consider the dynamics that show that there is a turn consisting of two spiral arms with one speed pattern, and four with another. They seem to collide at this point in time, and it also seems that the structure of two arms almost matches the time of their revolution with the time of revolution of the solar system. In fact, the estimate that the Milky Way has a very complex pattern (different number of arms, unbalanced symmetry and the estimate that the galaxy can rotate in a rigid pattern with one velocity pattern for the entire galaxy for ten to the power of eight (one hundred million) years is unrealistic.
- Mello's analysis is inconsistent with Spitzer's reconstruction, and is also inconsistent with the variation in CRF observed in iron meteorites.
- Mello's analysis refers to the restructuring of our knowledge of the structure of the spiral arms of the Engelmeier et al. galaxy. However, there are some critical problems in the way they do this. In particular, they estimate that there is an arm in the area where they do not see any arm in the density diagram, and they also ignore the arm passing through the area where the gas map clearly shows an elongated concentration of stars. In Mello's charts, he funds a pass through the arm, without the density required to support this assumption.
- Mello and his partners do not include additional effects of the speed, which is potentially asymmetrical like a cylinder (the arms show a correction of about 10%). They also do not include the effect of the orbital flutter parameter.
More on the subject on the science website
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The dominant paradigm that states that we are to blame for everything also seems overly "fishy". Maybe people are just trying to create hysteria and get their 15 minutes of fame?
The outgoing director of Greenpeace admits in an interview that the organization's predictions regarding the melting of the Arctic ice were too exaggerated: http://www.youtube.com/watch?v=NC7bE9jopXE
Yoav has two comments:
A]. In my opinion, the reference to Nir Shabib's theory should be meticulous
and more detailed. Its wholesale cancellation was done while ignoring important details.
The most essential point is that, even the Milky Way of the galaxy, being about 2000 light-years thick, may be inhomogeneous in its cosmic radiation density. There is no graph image of sharp rises and falls ("teeth") in the level of cosmic radiation density. The envelope graph shows an increase in the level of cosmic radiation relative to areas outside the Milka plane. It can be estimated that the thickness of each "tooth" in the graph is about one hundred to three hundred light years. According to this description, one can definitely expect changes in weather and temperature according to KDA in periods of decades, during periods of changes in the level of cosmic radiation.
All this does not eliminate the issue of atmospheric pollution with carbon dioxide gases, products of combustion of organic fuels. But, may put the effect of atmospheric pollution on global warming, in slightly different proportions.
B]. Will Yair?
Or: As far as I understand, this is his claim:
Criticisms of Shaviv's articles on the excellent site realclimate.org There are several more articles on the subject there
http://www.realclimate.org/index.php/archives/2008/03/a-galactic-glitch/
Shaviv's response
http://www.sciencebits.com/RealClimateSlurs
Note that he claims, among other things, that "only a third of global warming is man-made". That is, he does not reject global warming, he only claims that it has a cosmological addition. The cosmological theory should neglect considerations of the order of magnitude of time alone. The chance that a cosmological process will correspond in terms of time to a practical event by man is zero.
Let's say a person dies a second after he drank an unknown substance, of course there is a chance that he died of a serious illness and only by chance the event occurred in conjunction with drinking the substance, because of the amazing timing the chance of that is extremely small. The cosmological theory claims that because there is not enough evidence of the effect of the substance that the person drank and because the person was really sick then he died of the disease, this is of course unlikely because of the orders of magnitude of the times (only a second language, it is a second dictionary).
Does Shabib claim that the current climate warming is due to the entrance of a cloud of space into the galactic plane? This is not clear from the article, and it is possible that he does not claim so at all.
Yes, there are cyclical changes, but when humanity changes the chemical composition of the atmosphere in a very dramatic way in a zero period of time in geological or cosmological terms, the sharp changes observed in the climate will be the result of these changes, it is hard to believe that cosmological changes will occur precisely in our industrial century.
What's more, climatologists knew how to predict twenty-five years ago that continued carbon emissions would cause an increase in temperature, an increase that we are seeing now. No astrophysicist predicted this. The forecast of the climatologists is also clear, without limiting carbon emissions the temperature will continue to rise and endanger the existence of human society. What is Shaviv's forecast?
In my opinion, the title is too decisive and should have been put in quotation marks.
I would say after reading Shaviv's disclaimers that "it's not even wrong" is a slightly exaggerated phrase (and as readers know it's not original).
The problem in astrophysics is not that everything is models upon models, but that everything is models based on unfounded observations, predictions and beliefs.
This may be right and that one may be right - at the moment it's hard to see.