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18975
We read that the Chaco Anasazi builders used “large timbers” 5 meters long, 22 centimeters in diameter, and weighing 275 kilograms. As anyone who splits his own firewood could tell you, something is amiss here. The Handbook of Chemistry and Physics tells us that ponderosa pine has a density of about 0.5 gram per cubic […]
- Anthropology
Isotopes reveal sources of ancient timbers
Isotopic analysis of architectural timbers from ancient dwellings in the U.S. Southwest has shown from which distant forests the massive logs came.
- Astronomy
Probe’s comet encounter yields close-ups
A crippled NASA probe successfully navigated close enough to Comet Borrelly to capture and beam home black-and-white and infared images of its nucleus and new data about ions and other particles that radiate from it.
- Physics
Atomic Crowds Tied by Quantum Thread
Quantum states of record numbers of atoms—entire atom clouds—get blended together by physicists wielding a new, relatively simple technique in quantum telecommunications and computing.
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Joined at the Senses
As evidence accumulates for the existence of brain cells that handle many types of sensory information, some scientists challenge the popular notion that perception is grounded in five separate senses.
- Astronomy
After a failure, a new craft to sail
Despite the July 20 failure of its mission to test the unfurling of a solar sail in a suborbital trajectory, the Planetary Society announced plans in late August to conduct a second test of a sail-propelled craft.
- Astronomy
A meteorite’s pristine origins
A rare, carbon-rich meteorite that fell into a frozen Canadian lake last year ranks as the most pristine of such specimens ever found.
- Astronomy
Gravity’s lens: Finding a sextet of images
Astronomers have for the first time found a gravitational lens in which the image of a distant galaxy has been split into six distinct images.
- Astronomy
Gravity’s lens: Finding a dim cluster
Relying solely on a gravitational mirage rather than visible images, astronomers have discovered a previously unknown cluster of galaxies and measured its distance from Earth.
- Earth
Dust, the Thermostat
Analyses suggest that dust has profound, complex, and far-reaching effects on the planet's climate.
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Issues of Medical Research
Should researchers be allowed to tinker with our genetic codes, or create copies of human beings? Could we somehow be harming future generations by aiding sick people today? Public Agenda Online offers a nonpartisan guide to these and other policy issues related to medical research. Go to: http://www.publicagenda.org/issues/frontdoor.cfm?issue_type=medical_research
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From the September 26, 1931, issue
FLASH WELDING JOINS METAL AMID SHOWER OF SPARKS A brilliant shower of sparks for a few seconds, and two pieces of steel have become one, with a union as strong as the original metal itself. The picture on the front cover from the Pittsfield, Mass., works of the General Electric Company illustrates a recent adaptation […]
