Navigation Links
Research shows radiometric dating still reliable (again)
Date:9/15/2010

Recent puzzling observations of tiny variations in nuclear decay rates have led some to question the science of using decay rates to determine the relative ages of rocks and organic materials. Scientists from the National Institute of Standards and Technology (NIST), working with researchers from Purdue University, the University of Tennessee, Oak Ridge National Laboratory and Wabash College, tested the hypothesis that solar radiation might affect the rate at which radioactive elements decay and found no detectable effect.

Atoms of radioactive isotopes are unstable and decay over time by shooting off particles at a fixed rate, transmuting the material into a more stable substance. For instance, half the mass of carbon-14, an unstable isotope of carbon, will decay into nitrogen-14 over a period of 5,730 years. The unswerving regularity of this decay allows scientists to determine the age of extremely old organic materialssuch as remains of Paleolithic campfireswith a fair degree of precision. The decay of uranium-238, which has a half-life of nearly 4.5 billion years, enabled geologists to determine the age of the Earth.

Many scientists, including Marie and Pierre Curie, Ernest Rutherford and George de Hevesy, have attempted to influence the rate of radioactive decay by radically changing the pressure, temperature, magnetic field, acceleration, or radiation environment of the source. No experiment to date has detected any change in rates of decay.

Recently, however, researchers at Purdue University observed a small (a fraction of a percent), transitory deviation in radioactive decay at the time of a huge solar flare. Data from laboratories in New York and Germany also have shown similarly tiny deviations over the course of a year. This has led some to suggest that Earth's distance from the sun, which varies during the year and affects the planet's exposure to solar neutrinos, might be related to these anomalies.

Researchers from NIST and Purdue tested this by comparing radioactive gold-198 in two shapes, spheres and thin foils, with the same mass and activity. Gold-198 releases neutrinos as it decays. The team reasoned that if neutrinos are affecting the decay rate, the atoms in the spheres should decay more slowly than the atoms in the foil because the neutrinos emitted by the atoms in the spheres would have a greater chance of interacting with their neighboring atoms. The maximum neutrino flux in the sample in their experiments was several times greater than the flux of neutrinos from the sun. The researchers followed the gamma-ray emission rate of each source for several weeks and found no difference between the decay rate of the spheres and the corresponding foils.

According to NIST scientist emeritus Richard Lindstrom, the variations observed in other experiments may have been due to environmental conditions interfering with the instruments themselves.

"There are always more unknowns in your measurements than you can think of," Lindstrom says.


'/>"/>

Contact: Mark Esser
mark.esser@nist.gov
301-975-8735
National Institute of Standards and Technology (NIST)
Source:Eurekalert

Related biology news :

1. Plant biologists lead biobased-fuel research projects
2. Researchers build artificial ovary to develop oocytes into mature human eggs
3. Researchers nationwide ask for new focus on sudden death heart disorder
4. Global fisheries research finds promise and peril
5. WSU researchers discover key mechanism behind sleep
6. Interdisciplinary research looks at Charlottes green mystery
7. French national research agency funds PREDIMOL project
8. Louisiana Tech forestry professor helps to shape future of global industry research
9. MIT researchers develop a way to funnel solar energy
10. Stem cell research: What progress has been made, what is its potential?
11. Mount Sinai researchers analyze impact of chemical BPA in dental sealants used in children
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/11/2017)... NXT-ID, Inc. (NASDAQ:   NXTD ) ... appointment of independent Directors Mr. Robin D. Richards ... Directors, furthering the company,s corporate governance and expertise. ... Gino Pereira , Chief Executive ... their guidance and benefiting from their considerable expertise as we ...
(Date:4/4/2017)... NEW YORK , April 4, 2017   ... solutions, today announced that the United States Patent and ... The patent broadly covers the linking of an iris ... the same transaction) and represents the company,s 45 th ... our latest patent is very timely given the multi-modal ...
(Date:3/29/2017)... March 29, 2017  higi, the health IT company ... North America , today announced a Series ... acquisition of EveryMove. The new investment and acquisition accelerates ... tools to transform population health activities through the collection ... higi collects and secures data today on ...
Breaking Biology News(10 mins):
(Date:6/22/2017)... ... June 22, 2017 , ... For the months of ... a Spotlight series on “Cell Therapy Regulation” for its regenerative medicine ... on the unique regulatory challenges of stem cell medical research. , Stem cell ...
(Date:6/20/2017)... Rocky Hill, CT (PRWEB) , ... June 20, ... ... entrepreneurial support, today announced that the CTNext board of directors has formed a ... developed by a working group composed of institution presidents and other high-ranking representatives ...
(Date:6/20/2017)... ... ... Do More with OHAUS , With the launch of the new laboratory ... industry, to extending its expertise across the entire laboratory to a range of life ... allowing for its customers to 'Do More' in the lab. , Efficiency and ...
(Date:6/19/2017)... ... June 19, 2017 , ... A colony of healthy honey bees ... tissues by delivering pollen and nectar containing nutrients necessary for growth and survival. Better ... , Many recent indicators point to a decline in honey bee health. Sick and ...
Breaking Biology Technology: