ABC: For many, the arguments surrounding global warming and the ways to combat it can be convoluted and confusing. Delivering the first of the Sydney Ideas lectures for 2010, world renowned climate scientist Michael Oppenheimer outlined the evidence for global warming and explained how it was gathered.
Michael Oppenheimer is a Professor of Geosciences and International Affairs at Princeton University. He was the Lead Author on the third and fourth assessment reports of the Intergovernmental Panel on Climate Change, published in 2001 and 2007 respectively. Before joining the faculty at Princeton, he spent 20 years as chief scientist at The Environmental Defence Fund.
Also available on fora.tv. Length: 95 minutes 31 seconds (intro until 6:40, Q&A starts around 70 minutes).
The hottest cultural controversy of 2005 was the Intelligent Design challenge to the theory of evolution, being played out in classrooms and courtrooms across America. The crux of the argument made by proponents of Intelligent Design is that the theory of evolution is in serious trouble. They claim that the evidence for evolution is weak, the gaps in the theory are huge, and that these flaws should be taught to students. In this brilliant synthesis of scientific data and theory, Occidental College geologist, paleontologist, and evolutionary theorist Dr. Donald Prothero will present the best evidence we have that evolution happened, why Darwins theory still matters, and what the real controversies are in evolutionary biology.
Dr. Donald Prothero teaches Physical and Historical Geology, Sedimentary Geology, and Paleontology. His specialties are mammalian paleontology and magnetic stratigraphy of the Cenozoic. His current research focuses on the dating of the climatic changes that occurred between 30 and 40 million years ago, using the technique of magnetic stratigraphy. He is the author of “Evolution of the Earth,” “Bringing Fossils to Life,” “After the Dinosaurs,” “Horns, Tusks, and Flippers: The Evolution of Hoofed Mammals,” and the textbook “Sedimentary Geology.”
Richard H. Thaler, Director of the Center for Decision Research at the University of Chicago Graduate School of Business, is the father of Behavioral Economics. In preparation for a new book he asked EDGE contributors to answer this question:
The flat earth and geocentric world are examples of wrong scientific beliefs that were held for long periods. Can you name your favorite example and for extra credit why it was believed to be true?
As of today, there are 61 responses which make for fascinating reading on how science has corrected itself and our views of nature.
Topics (with comments on both bad and correct science or beliefs) include: plate tectonics, cosmic inflation, prions, quantum entanglement, the force of gravity, the great chain of being, bird intelligence, the four humours of human physiology, luminiferous aether, bad air disease theory, Peripatetic Mechanics of Aristotle, stress theory of ulcers, intelligent design/creationism, the age of the Earth, cell regeneration, spontaneous generation of life, vitalism, unifunctional components of the brain, security by obscurity, whales as fishes, group selection, unilinear cultural evolution, static universe, Lamarckism, nature/nurture, the existence of a vacuum, the human brain vs. the heart, and more…
The Earth’s magnetic field varies on many time scales, waxing and waning in strength, and periodically completely reversing direction. The geologic record of these variations provides important information on the history of our planet. Join Scripps Oceanography geoscientist Jeff Gee for a fascinating glimpse into his fieldwork in paleomagnetism — from autonomous aircraft measurements over the open ocean to exploration of rock exposures in remote regions of Antarctica. Series: Perspectives on Ocean Science
The embedded video skips the introduction. YouTube offers the option to download the video as a mp4 file.
Researchers have found a primitive Earth mantle reservoir on Baffin Island in the Canadian Arctic. Geologist Matthew Jackson and his colleagues from a multi-institution collaboration report the finding–the first discovery of what may be a primitive Earth mantle–this week in the journal Nature.
The Earth’s mantle is a rocky, solid shell that is between the Earth’s crust and the outer core, and makes up about 84 percent of the Earth’s volume. The mantle is made up of many distinct portions or reservoirs that have different chemical compositions.
Scientists had previously concluded that the Earth was slightly older than 4.5 billion years old, but had not found a piece of the Earth’s primitive mantle.
Until recently, researchers generally thought that the Earth and the other planets of the solar system were chondritic, meaning that the mantle’s chemistry was thought to be similar to that of chondrites–some of the oldest, most primitive objects in the solar system. Assuming a chondritic model of the Earth, a piece of the primitive mantle would have certain isotope ratios of the chemical elements of helium, lead and neodymium.
The model that the Earth was chondritic was called into question with a discovery five years ago by a team at the Carnegie Institution of Washington, which suggested the ratio of neodymium on Earth was higher than what would be expected if the Earth were indeed chondritic.
That finding changed the neodymium ratio expected in the primitive mantle and in turn, changed where researchers should be looking to find evidence of a primitive mantle. According to the lead author, Matthew Jackson, “We had been looking under the wrong rock.”
Since many of the ancient rocks have melted over time, finding a piece of the primitive mantle means studying lavas. Lavas retain the same isotopic composition of the rocks that have melted into the lava. Therefore, testing the lava’s composition is identical to testing the original rock’s composition.
When the assumption about the neodymium ratio was altered, Jackson and his colleagues knew they should take a look at lava samples from Baffin Island, since those samples contained the correct ratios of helium and neodymium. They discovered that the lavas also had the correct ratio for lead. The lead isotopes suggest that the samples from Baffin Island date the lava’s mantle source reservoir to between 4.55 and 4.45 billion years old, only a little younger than the age of the Earth. The lava sample comes from an ancient rock that melted 62 million years ago.
This is the view of the basalts along the northeastern coast of Baffin Island.
When the researchers studied the composition of the lava found at Baffin Island, they discovered that the sample had the correct ratios of all three chemical elements–helium, lead, and the new non-chondritic neodymium ratio. This discovery suggests that the sample from Baffin Island is the first evidence for the oldest mantle reservoir.
This study challenges the idea that the Earth has a chondritic primitive mantle and according to Matthew Jackson is, “suggesting an alternative.” One possibility, according to Jackson, is that “the early Earth went through a differentiation event and the Earth’s crust was extracted from the early mantle and is now hidden in the deep earth; the hidden crust and the mantle found on Baffin Island would sum to chondritic.”
The discovery in Gabon of more than 250 fossils in an excellent state of conservation has provided proof, for the first time, of the existence of multicellular organisms 2.1 billion years ago. This finding represents a major breakthrough: until now, the first complex life forms (made up of several cells) dated from around 600 million years ago.
Virtual reconstruction (by microtomography) of the external morphology (on the left) and internal morphology (on the right) of a fossil specimen from the Gabonese site. (Credit: Copyright CNRS Photo Library / A. El Albani & A. Mazurier)
These new fossils, of various shapes and sizes, imply that the origin of organized life is a lot older than is generally admitted, thus challenging current knowledge on the beginning of life. These specimens were discovered and studied by an international multidisciplinary team of researchers led by Abderrazak El Albani of the Laboratoire “Hydrogéologie, Argiles, Sols et Altérations” (CNRS/Université de Poitiers). Their work, due to be published in Nature on 1st July, will feature on the cover of the journal.
The first traces of life appeared in the form of prokaryotic organisms, in other words organisms without a nucleus, around three and a half billion years ago. Another major event in the history of life, the “Cambrian explosion” some 600 million years ago, marked a proliferation in the number of living species. It was accompanied by a sudden rise in oxygen concentration in the atmosphere. What happened between 3.5 billion and 600 million years ago though? Scientists have very little information about this era, known as the Proterozoic. Yet, it is during this crucial period that life diversified: to the prokaryotes were added the eukaryotes, single or multicelled organisms endowed with a more complex organization and metabolism. These large-sized living beings differ from prokaryotes by the presence of cells possessing a nucleus containing DNA.
While studying the paleo-environment of a fossil-bearing site situated near Franceville in Gabon in 2008, El Albani and his team unexpectedly discovered perfectly preserved fossil remains in the 2.1 billion-year-old sediments. They have collected more than 250 fossils to date, of which one hundred or so have been studied in detail. Their morphology cannot be explained by purely chemical or physical mechanisms. These specimens, which have various shapes and can reach 10 to 12 centimeters, are too big and too complex to be single-celled prokaryotes or eukaryotes. This establishes that different life forms co-existed at the start of the Proterozoic, as the specimens are well and truly fossilized living material. (…)
Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago. Nature, 2010; 466 (7302): 100 DOI: 10.1038/nature09166
Scientists track electrons in molecules (PhysOrg)
Physicists in Europe have successfully glimpsed the motion of electrons in molecules. The results are a major boon for the research world. Knowing how electrons move within molecules will facilitate observations and fuel our understanding of chemical reactions.
Sunburnt plants ‘myth’ is debunked (Telegraph UK)
A long held belief among gardeners that watering plants in the heat of the midday sun can damage the leaves has been proved false following research by scientists.
Tiny blood vessels in brain spit to survive (ScienceDaily)
Scientists have discovered capillaries have a unique method of expelling debris, such as blood clots, cholesterol or calcium plaque, that blocks the flow of essential nutrients to brain cells. The capillaries spit out the blockage by growing a membrane that envelopes the obstruction and then shoves it out of the blood vessel. Scientists also found this critical process is up to 50 percent slower in an aging brain and likely results in the death of more capillaries.
Spending time in nature makes people feel more alive, study shows (ScienceDaily) >
Being outside in nature makes people feel more alive, finds a series of studies. And that sense of increased vitality exists above and beyond the energizing effects of physical activity and social interaction that are often associated with our forays into the natural world.
Beethoven unlikely to have died from lead exposure (ScienceDaily)
A researcher has measured the amount of lead in two skull fragments of Ludwig van Beethoven and found that it was unlikely for lead poisoning to have caused the renal failure that was partly responsible for Beethoven’s death, eliminating one of the many suggested causes of death for the famed composer.