Theos-Talk Archives (August 2005 Message tt00325)

Cass: Another confirmation that Neanderthal and australopithecus shared thesame place at the same time.

 

ASU researcher Ana Pinto is shedding some light on an age-old mystery in anthropology: What was the relationship between Neanderthals and early humans? 

When the team’s test excavation reached the 12th level, they found what they had been hoping for: primitive scraping tools, fashioned out of retouched stone flakes, lying next to bone fragments of some prehistoric feast. The tools differed from those normally associated with modern humans, indicating they belonged to a Neanderthal culture. 

Given that Pinto’s evidence shows that Neanderthals and modern humans shared a common location at a time when evidence shows that both species may have been in Europe, it seems likely that the two species would have encountered one another. 



 

Cass: Keely's invention might still be verified yet!

August 29, 2005 

  

Chemists are several steps closer to teasing hydrogen fuel from water usingman-made molecular devices that collect electrons and use them to split hydrogen from oxygen. 

 

 

Cass: Is Einstein's theory being questioned?

Either of these two scenarios rules out Einstein's cosmological constant. In their paper Linder and Caldwell show, for the first time, how to cleanly separate Einstein's idea from other possibilities. Under any scenario, however, dark energy is a force that must be reckoned with. 

 



Image: Today's universe is expanding at an accelerating rate because dark energy counteracts the force of gravity. In the early universe matter was closer together, and gravity still slowed its expansion. 

Says Linder, "Because dark energy makes up about 70 percent of the content of the universe, it dominates over the matter content. That means dark energy will govern expansion and, ultimately, determine the fate of the universe." 

In 1998, two research groups rocked the field of cosmology with their independent announcements that the expansion of the universe is accelerating. Bymeasuring the redshift of light from Type Ia supernovae, deep-space stars that explode with a characteristic energy, teams from the Supernova Cosmology Project headquartered at Berkeley Lab and the High-Z Supernova Search Team centered in Australia determined that the expansion of the universe is actually accelerating, not decelerating. The unknown force behind this accelerated expansion was given the name "dark energy." 

Prior to the discovery of dark energy, conventional scientific wisdom held that the Big Bang had resulted in an expansion of the universe that would gradually be slowed down by gravity. If the matter content in the universe provided enough gravity, one day the expansion would stop altogether and theuniverse would fall back on itself in a Big Crunch. If the gravity from matter was insufficient to completely stop the expansion, the universe would continue floating apart forever. 

"From the announcements in 1998 and subsequent measurements, we now know that the accelerated expansion of the universe did not start until sometime in the last 10 billion years," Caldwell says. 

Cosmologists are now scrambling to determine what exactly dark energy is. In 1917 Einstein amended his General Theory of Relativity with a cosmological constant, which, if the value was right, would allow the universe to exist in a perfectly balanced, static state. Although history's most famous physicist would later call the addition of this constant his "greatest blunder," the discovery of dark energy has revived the idea. 

 



Image: Dark energy is an exotic repulsive force that could make up as much as three-quarters of the cosmos. Possibilities include a cosmological constant or dynamical quintessence, both of which can be represented by scalar fields, like a field of springs covering every point in space. For a cosmological constant (left), each spring would be the same length and motionless.For quintessence (right), each spring would be stretched to a different length. 



 


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