Global Cooling, Global Warming
Aug 8 at 2:02pm by Aileen
Researchers from Oregon State University and other institutions have published an article in the journal Science that they say puts to rest a long scientific debate on the causes of periodic ice ages in the history of our planet. The conclusion? Earth Wobbles.
The last major ice age reached its peak about 26,000 years ago, held steady for about 7,000 years, then began melting 19,000 years ago. The melting was caused by an increase in solar radiation, the researchers say, and not by carbon dioxide’s “greenhouse” effect, or any changes in ocean temperatures. These mechanisms have been cited recently by some scientists trying to understand what appears to be happening now with the increase in global temperatures termed “Global Warming” and said to be caused primarily by pollution from human activities.
The researchers analyzed 6,000 dates and locations of ice sheets to define when they started to melt. This confirmed a theory developed more than fifty years ago that held small but definable changes in Earth’s rotation as the trigger for both the accumulation of ice and its melting cycle. Putting that together with changes in the Earth’s axis and rotation going back 50 million years, they found that the gravitational influences of the larger planets – primarily Saturn and Jupiter – leads to predictable cycles.
Right about now, the scientists say, we should be changing from an interglacial period toward conditions that will ultimately lead to another ice age. That is, if human contributions to Global Warming don’t thwart the process. Meanwhile, a close look at plans to mitigate global warming with ‘Geoengineering’ suggests that such plans may well do more harm than good.
Research presented at a symposium at the Ecological Society of America’s annual meeting concludes that geoengineering is potentially dangerous, and that the risks outweigh the benefits. Plans such as limited nuclear detonations and subsequent fires to release lots of carbon into the atmosphere, seeding the atmosphere with light colored sulfur particles to mimic gigantic volcanic eruptions, and seeding the oceans with iron to increase carbon uptake all come with side-effects that could be disastrous, ecologists say.
Indeed, if we are starting to ‘wobble’ to the gravitational tune of our giant planetary neighbors toward another ice age, taking big efforts to cool the planet right now could actually speed up the process! Perhaps we should put off the big projects until we know more about all this, eh?
Popularity: 38% [?]
About those Mammoths? …Never Mind.
Jan 27 at 8:08pm by Aileen
On the fifth of this month I posted Supernovae, Comets and Holey Mammoth Tusks, about a recently-developed theory with apparently lots and lots of confirming evidence, that purported to demonstrate the mass extinction of North American megafauna – wooly mammoths, giant bison, saber-tooth cats, etc. – was the result of effects from a supernova explosion 250 light years from earth, and a 10-kilometer wide comet produced that hit or exploded just above Chicago nearly 13,000 years ago.
Well, this week researchers from the University of Bristol say they have disproven that theory, by examining charcoal and pollen records for the great fires the comet must have caused. Their results, they say, provide no evidence of continental-scale fires. Though they do say their examination of this material dated between 15,000 and 10,000 years ago, somehow establishes that an increase in large-scale wildfires all over the world during the past 10 years is attributable to global warming.
Ah, well. So much for grand theories about great and sudden climate change in past ages, as well as ongoing disagreements about climate change in the current age. Perhaps what is best to be learned from this back and forth of disagreements about evidence and what it means is to take the pronouncements of various groups of scientists with a grain of salt, for their conclusions are often so short-lived as to not even make it past the publication schedule of two successive issues of the same journal!
Eventually, maybe, they’ll work it all out.
And while we’re here looking at research from different sources that can end up with entirely different conclusions, check out a new project site from Creative Commons – ScienceCommons. Making the Web work for science, to develop technologies to make research, accumulated data and materials easier to find and use. I’ll be reporting on this again in the near future, so stay tuned!
Links:
Supernovae, Comets and Holey Mammoth Tusks
North American Comet Impact Theory Disproved
ScienceCommons
Popularity: 24% [?]
Supernovae, Comets and Holey Mammoth Tusks
Jan 5 at 11:11pm by Aileen
…a tale of mass extinction and woe
Blue Sky Studios
Not so very long ago the wizened gatekeepers of scientific orthodoxy staged a vigorous and extremely nasty campaign designed to prevent any possibility that impressionable science students or the great unwashed masses might come to suspect that things in our cosmic neighborhood were ever anything but perfectly peaceful, perfectly ordered, and perfectly safe. It was the middle of the 20th century, a bit over 150 years since the staid scientists at the Royal Society in London had discovered the hard way that stones really can fall from the sky despite their pronouncements to the contrary.
Yet the publication of Worlds in Collision in 1950 – and Ages in Chaos in 1952 – purported to demonstrate that the Earth had suffered some serious cosmic upheavals within the memory of human civilizations. These ideas drove such astronomical lions as Harlow Shapley to use every underhanded method and scheme available to destroy the author and reassure the public once again that, despite all evidence and witness through the ages, stones do NOT fall from the sky, comets do NOT wreak havoc on the Earth, and the perfect clockwork of cosmic orderliness is NOT violated by disorderly events. Thus did the notorious Velikovsky Affair take its place in the annals of science’s ample history of internal turf wars.
Many young people today are quite used to the idea that our planet has been bombarded by cosmic billiard balls of one sort or another, learning about the epochal events that marked transitions from one age to another, usually by causing mass extinctions of life forms and altering the course of evolution. Even children’s books and movies portray the catastrophic events of 65 million years ago when a large asteroid ended the age of the dinosaurs. Yet apart from those now-recognized disasters in the distant past of our planet, scientists have tended to remain skeptical of the notion that such world-shattering events have ever occurred – or been recorded – in the short (~100,000 year) history of human beings on this planet.
Popularity: 23% [?]
Meanwhile, Some Chaos in the Neighborhood
Dec 22 at 5:05pm by Aileen
There have been some interesting events going on in our solar system since the turn of the new millennium, just coming up on being 8 years old (when counted as the New Year’s transition 2000 to 2001). And the most recent situation here on planet earth bodes ill for sunbathers and electronic communications.
Our sun (Old Sol) has a predictable 11-year cycle of magnetic pole-flipping – with accompanying sunspots and coronal mass ejections [CMEs] of high-energy ions. The most recent pole-flip occurred between 2000 (north pole) and 2002 (south pole). Our planet has also been known to flip its poles, but on a much longer period cycle that averages ~500,000 years. It’s been about 780,000 years since this last occurred, so it’s probably not too surprising that by 2004 scientists were noticing that our field was fading fast.
Back then scientists were fairly convinced that the process of field reversal takes hundreds or thousands of years to accomplish, so the panic level wasn’t high. Earth’s magnetic field produces a “magnetosphere” that shields the surface and lower atmosphere from incoming solar wind, CMEs and cosmic rays by directing them around the planet. Occasional solar radiation does break through and wreak temporary havoc to our electrical grids and communications technologies. And some birds, turtles and bees rely on the magnetic field of the earth in order to navigate.
Popularity: 22% [?]
Happy Birthday, International Space Station!
Nov 20 at 6:06pm by Aileen
SFWA
The International Space Station marks its 10th Anniversary this week, in commemoration of the launch of the first bus-sized component – Zarya – on November 20, 1998 from Kazakhstan. Happy Birthday to this great achievement in international cooperation for the exploration of space and the progression of space-based science!
A joint venture of the US’s NASA, the Russian Federal Space Agency, Canadian Space Agency, Jaqpan Aerospace Exploration Agency, and 11 members of the European Space Agency – Belgium, Denmark, France, Germany, Italy, the Netherlands, Norway, Spain, Sweden, Switzerland and the UK. Do things come any more international than that?
The world’s space-based science conglomerate brags a total of more than 25,000 cubit feet of room after a decade of flights bringing more experiments and more modules, and the participation of 167 astronauts from 14 countries. Recently American astronauts were able to cast their ballots in the General Election from the station, making them the most “absent” of all absentee voters ever!
Estimated to cost around $100 billion over the life of its mission, consensus opinion is that the space station will go down in history as precursor to permanent moon bases, a first step in future journeys to the planet Mars. The station could be abandoned as early as 2011, but may, like several of the recent Mars rovers, end up living well past its life expectancy. Its future is tied to what happens with the US shuttle fleet, and whether or not other nations involved will develop their own fleets to service the station and transport supplies and experiments.
So raise a toast of your favorite to the night sky and consider for a few moments just how far we’ve come since Sputnik. Happy Birthday, ISS!
Links:
Nations Mark 10th Anniversary of ISS
NASA – International Space Station
Wikipedia: International Space Station
Popularity: 13% [?]
Cassini Revisits Enceladus
Aug 14 at 7:07pm by Aileen
Returns Very Cool Pix
Fractures, or “tiger stripes,” where icy jets erupt on Saturn’s moon Enceladus will be the target of a close flyby by the Cassini spacecraft on Monday, Aug. 11. – JPL/NASA
Calling all space geeks! Check out the photos returned from Monday’s 50-km fly-over of Enceladus’ ridged south pole “geyser region” at JPL’s Cassini-Huygens Images page. Well done indeed!
And to get the low-down on what they’re looking at and why, Discover magazine collects the data in readily accessible links here.
Saturn and its 52 moons are a fascinating system, and Cassini keeps returning spectacular images and data that will have scientists scratching their heads for years. I personally am following the Titan and Iapetus fly-bys due to long time fascination with these particular moons, but Enceladus is one of the solar system’s most likely places to find life that’s not right here on planet earth. Here’s some useful links…
Cassini-Huygens Images
Discover: Cassini Snaps Pictures of Saturn’s Geyser-Spouting Moon
Moons: Titan
Moons: Iapetus
Popularity: 8% [?]
A “Swarm” of Earthquakes off Oregon
Apr 14 at 2:02pm by Aileen
Over the last ten days scientists at Oregon State University [Hatfield Marine Science Center] have recorded more than 600 earthquakes emanating from offshore, several of which registered 5.0 or higher. The puzzling aspect of this quake swarm is that they’re not located at the edge of the region’s tectonic plate boundaries, but in the middle of the Juan de Fuca plate itself.
Using hydrophones left over from submarine surveillance during the Cold War, the researchers admit they do not understand what’s happening to cause this seismic activity. The quakes originate about 150 nautical miles southwest of Newport, Oregon in a basin between two subsurface faults where previous earthquake clusters have been recorded.
As magma gets injected into the crust to push the plates apart, quake swarms are fairly common and sometimes lava breaks through onto the sea floor. What sort of tectonic process is causing this swarm in the middle of the plate is unknown, but researchers will be keeping a close eye on it in hopes of finding out.
Links:
Unusual Earthquake Swarm off Oregon
2006 Mexican Tectonic Plate Motion Reversal
Popularity: 13% [?]
10 Earth Science Questions for the 21st Century
Mar 15 at 5:05pm by Aileen
The National Research Council has identified and reported on Ten Questions that will shape 21st century earth science. Some may be a little surprised that these questions are still unanswered, having been told in no uncertain terms in science classes in the last century that science already had definitive answers to questions like how the earth and other planets in our solar system formed. Live and learn. Here’s a bare list of the identified questions…
1. How did earth and other planets form?
Scientists still do not know enough about how our planet got its elements to understand its evolution, or why other planets in our system are very different.
2. What happened during the first 500 million years?
Current scientific belief is that another planet collided with ours during the late formation stage, creating the moon and melting this planet all the way to its core. Yet unknown is how (and when) the Earth developed its atmosphere and oceans.
3. How did life begin?
Scientists hope to obtain evidence from rocks and minerals, as well as investigations of Mars and other members of our system.
Popularity: 21% [?]
The Great Meteor-Hunt is On!
Mar 10 at 8:08pm by Aileen
Astronomers Capture Rare Meteor On Video
Astronomers at the Physics and Astronomy Department at the University of Western Ontario captured video of a meteor falling toward the Parry Sound area on the night of March 5. The video can be seen at UWO’s website using this link.
Because the meteor was tracked to an altitude of 24 kilometers – much closer than the 60-70 km altitude at which most incoming meteoroids burn up – the astronomers have enlisted the help of local residents in the area to search for meteorites they suspect can be found on the ground.
Popularity: 10% [?]
New Theories and X-Rated Space Follies
Dec 13 at 6:06pm by Aileen
Quantum Iron in the Core, Killer ETs and Indecent Singularities
Researchers have recently discovered some new things about both our own planet’s core and our close encounters of the closest kind with extraterrestrial billard balls. Beginning here at home, geophysics researchers published a paper in Science reporting that Deep Earth Model Challenged by New Experiment.
Apparently the iron concentrated in the lower Earth mantle behaves quite differently than previous models predicted. Instead of finding a particular, thin “transition zone” at a certain depth where the temperature and pressure ‘flips’ the spin of electrons in Iron atoms to a paired state (a quantum effect that affects the density of the iron compounds), the experiments found a whole new region in the lower mantle where both high and low spin states coexist in the same crystal structure.
This continuous transition zone grew to a thickness of nearly 750 miles, comprising the entire region between the depths of 620 and 1,365 miles beneath the surface of the Earth.
Popularity: 9% [?]
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