Einstein Was Right (Again):
NIST/MIT Confirm E=mc2
instrument called GAMS4, originally designed and built at
NIST and now located at Institut Laue Langevin in France,
was used in experiments that helped to confirm Einstein’s
famous equation E=mc². GAMS4 measured the angle at
which gamma rays are diffracted by two identical crystals
made of atoms separated by a known distance. The two crystals
are the dark gray rectangles on circular platforms in the
foreground and background of the photo.
by Artechnique, Courtesy of ILL
a high resolution version of this image.
Einstein was correct in his prediction that E=mc2,
according to scientists at the Massachusetts Institute of Technology
(MIT), the Commerce Department’s National Institute of Standards
and Technology (NIST), and the Institute Laue Langevin, Genoble,
France (ILL) who conducted the most precise direct test ever of
what is perhaps the most famous formula in science.
described in the Dec. 22, 2005, issue of Nature,* the
researchers added to a catalog of confirmations that matter and
energy are related in a precise way. Specifically, energy (E)
equals mass (m) times the square of the speed of light (c2),
a prediction of Einstein’s theory of special relativity.
By comparing NIST/ILL measurements of energy emitted by silicon
and sulfur atoms and MIT measurements of the mass of the same
atoms, the scientists found that E differs from mc2
by at most 0.0000004, or four-tenths of 1 part in 1 million. This
result is “consistent with equality” and is 55 times
more accurate than the previous best direct test of Einstein’s
formula, according to the paper.
tests are important because special relativity is a central principle
of modern physics and the basis for many scientific experiments
as well as common instruments like the global positioning system.
Other researchers have performed more complicated tests of special
relativity that imply closer agreement between E and mc2
than the MIT/NIST/ILL work, but additional assumptions are required
to interpret their results, making these previous tests arguably
Nature paper describes two very different precision measurements,
one done at MIT by a group led by David Pritchard and another
done at the ILL by a NIST/ILL collaboration led by the late physicist
Richard Deslattes (NIST) and Hans Börner (ILL). Deslattes
and his collaborators developed methods for using optical and
X-ray interferometry—the study of interference patterns
created by electromagnetic waves—to precisely determine
the spacing of atoms in a silicon crystal, and for using such
calibrated crystals to measure and establish more accurate standards
for the very short wavelengths characteristic of highly energetic
X-ray and gamma ray radiation. Börner and his collaborators
were responsible for a highly successful gamma-ray measurement
program at the ILL.
information, see www.nist.gov/public_affairs/releases/einstein.htm.
Enjoy New Year's Eve a Second Longer!
can toot your New Year's horn an extra second this year,
physicists at the National Institute of Standards and Technology
(NIST). Along with the rest of the world's atomic timekeepers,
NIST's time and frequency experts will insert a second
(known as a leap second) into their time scale on Dec.
the first time in seven years.
1972 (when the world went to the current system of atomic
timekeeping) until Dec. 31, 1998, 22 seconds were added
to Coordinated Universal Time (the official world time known
as UTC) to keep it in sync with the Earth's rotation (which
can speed up or slow down due to many factors). Since 1999
until recently, that rotation and UTC had stayed closely
enough in harmony to not require the adjustment of adding
a leap second.
This year's leap second will be implemented by adding an
extra second to atomic clocks at NIST in Boulder, Colo.,
and other sites around the world. Normally, the last second
of the year would be 23:59:59 UTC on Dec. 31, 2005, while
the first second of the new year would be 00:00:00 UTC
Jan. 1, 2006. The leap second will be added at 23:59:59
UTC (06:59:59 p.m. Eastern Standard Time) on Dec. 31,
so that atomic clocks will read 23:59:60 UTC before changing
to all zeros.
proposal to eliminate leap seconds altogether in the future
is still under consideration by the international bodies
in charge of coordinating world time.
more information on leap seconds, go to http://tf.nist.gov/timefreq/general/leaps.htm.
E. Newman, email@example.com,
Solve Mystery of the 'Unicorn' Whale
unusual unicorn-like tusk of the narwhal whale turns out
to be a sophisticated sensing organ, according to recent
Photo by Glenn Williams
the subject of mythical accounts of magical power, the
tusk of the narwhal, or “unicorn” whale has proved
to be an extraordinary sensory organ, according to a team
researchers from Harvard University, the Smithsonian Institution,
and the Paffenbarger Research Center of the American Dental
Association Foundation (ADAF) at the National Institute of
Standards and Technology (NIST). The team's results were presented
Dec. 13 at a technical conference in San Diego.*
up to 2.7 meters or about 9 feet long, the tusk is traversed by
up to 10 million nerve pathways. These pathways connect the outside
of the tusk to a central core of nerves leading to the animal’s
brain. Based on experiments with samples of the tusk as well as
with a captured narwhal whale, the research team found that the
tusk’s sensory system may be capable of detecting changes
pressure, salinity and other factors that may help a narwhal survive
its Arctic environment.
NIST, Naomi Eidelman, Anthony Giuseppetti and Frederick Eichmiller
of the ADAF examined samples of narwhal tusk with both infrared
microspectroscopy and scanning electron microscopy. Their work
revealed the tusk’s unusual structure.
most mammalian teeth are softer on the inside and harder
on the outside, narwhal tusk appears to be made “inside
Eichmiller. The researchers believe the softer outer layers
of the tusk may act like a shock absorber to help prevent
was funded by NIST, ADAF, Harvard School of Dental Medicine,
National Geographic Society, Sunstar Butler, Smithsonian
Institution Center for Arctic Studies, Astro-Med Inc., and
the Federal Department of Fisheries and Oceans, Canada.
Nweeia, N. Eidelman, F.C. Eichmiller, A.A. Giuseppetti, Y.G.
Jung, Y. Zhang, "Hydrodynamic sensor capabilities and structural
resilience of the male narwhal tusk," 16th Biennial Conference
on the Biology of Marine Mammals, Dec. 13, 2005, San Diego,
close-up of a tubule reveals a cave-like opening ultimately
leading to inner nerves along the tusk core. (Magnified
credit: Frederick Eichmiller, Paffenbarger Research
high-resolution version of this image.
scanning electron micrograph shows the tunnel-like
tubules that provide pathways for millions of sensing
nerves within a narwhal whale's tusk. (Magnified 200
credit: Frederick Eichmiller, Paffenbarger Research
high-resolution version of this image.
Metrics Proposed for Firefighter Thermal Imagers
are starting to recognize the potential usefulness of thermal
imagers or infrared cameras for saving property and lives.
Choosing the most appropriate thermal imager for a particular
use, however, can be difficult. No standardized performance
guidelines exist for infrared camera devices specifically
tailored to first responder needs. For example, the devices
may be used to locate victims in a burning building or to
pinpoint fire sources in a smoky environment.
the National Institute of Standards and Technology (NIST)
hope to change that situation. Last month they submitted recommendations
to the National Fire Protection Association (NFPA) that outline
evaluation methods for thermal imagers as used in six critical
emergency situations. These recommendations include tests
to assess durability as well as image quality.
firefighter applications represent less than 10 percent
the $1.2 billion worldwide annual market for infrared cameras,
the NIST researchers say that the performance evaluation
will be very important to the first responder community. “Right
now," says Francine Amon, leader of the NIST team, “fire
departments have to base their thermal imager purchasing
on manufacturer’s literature, personal experience and
word-of-mouth recommendations. Standardized performance metrics
and test methods should improve the selection process for
these potentially life-saving devices that cost an average
of $10,000 each. They also should encourage technological
innovation for the first responder community.”
NIST researchers suggest performance metrics that would
reveal a thermal camera’s ability to (1) detect unusually
hot spots, such as electrical outlets and light ballasts;
(2) guide fire hose streams toward the fire source; (3) “size-up”
thermal conditions inside a building, such as hot walls or
ceiling sections, in preparation for entry into a room; (4)
identify faces and bodies of firefighters and victims for
search and rescue operations; (5) find hot spots and hidden
smoldering during reconnaissance in the aftermath of a fire;
and (6) locate hazardous material spills. The NFPA’s
Committee on Emergency Service Electronic Safety Equipment
is expected to review the suggestions in 2006.
to NIST, the Department of Homeland Security (DHS) and
United States Fire Administration (USFA) are providing funding
for NIST’s ongoing thermal imaging performance evaluation
project. NIST, DHS and USFA recently sponsored a workshop
at NIST on “Thermal Imaging Research Needs for First
Responders.” A copy of the proceedings is available
at http://www.fire.nist.gov/. A
USFA Web site discussing the project is available at www.usfa.fema.gov/research/safety/nist3.shtm.
Enhancements Upgrade NIST Mass Spectra Library
three years of development, the National Institute of Standards
and Technology (NIST) has released a major upgrade of the
widely used NIST/EPA/NIH Mass Spectral Library.
library is an encyclopedic database of “fingerprints”
used to identify chemical compounds with a technique called
mass spectrometry. The method uses the unique masses of
to identify unknown chemicals. Samples are first vaporized,
then ionized by stripping away one or more electrons, leading
to fragmentation. These fragments are finally sorted by their
mass-to-charge ratios using magnetic or electric fields,
a “mass spectrum.” Even a sample of a pure element
generally produces a spectrum with several peaks representing
a unique distribution of masses due to isotopes with varying
numbers of neutrons.
edition of the library, NIST 05, adds approximately 20,000
new spectra, bringing the total number of compounds found
in the database to more than 163,000. Each spectrum has been
analyzed and critically evaluated to ensure that the library
has the best possible current data.
upgraded library also includes two important new classes
reference data. Gas-phase “retention index” data—used
in gas chromatography to identify volatile organic compounds—have
been added for more than 25,000 different compounds. And
separate collection of more than 2,000 tandem mass spectrometry
(MS/MS) spectra has been added. MS/MS spectra arise from
process where the ionization and fragmentation steps are
separated. They have become widely used “fingerprints"
for compounds in complex biological samples in fields such
proteomics and metabolomics. This is the first evaluated,
general purpose MS/MS data library available to the general
in collaboration with the Environmental Protection Agency
and the National Institutes of Health, the NIST 05 library
is available with Version 2.0d of the NIST MS Search Program
for Windows through authorized dealers. Details are available
from the NIST Standard Reference Data Program at www.nist.gov/srd/nist1a.htm.
Contact: Michael Baum, firstname.lastname@example.org,
the Fate of Drugs in Wastewater
at the National Institute of Standards and Technology
have published an interesting study that sheds light on the
fate of a familiar pharmaceutical as it enters the waste
In work initially
described in NIST TechBeat last
NIST chemists investigated probable chemical reactions involving
acetaminophen when the drug is subjected to typical wastewater
processing. Acetaminophen is the most widely used pain reliever
in the United States, and a study of 139 streams by the U.S.
Geological Survey found that it was one of the most frequently
detected man-made chemicals.
scientists found that the drug readily reacts in chlorine
to form at least 11 new products, at least two of which are
known to be toxic. The results, according to lead author
Bedner, demonstrate that environmental scientists need to
be concerned about downstream reaction products as well
the original waste materials. “The issue is what you
should be looking for in the environment,” she says. “When
you are looking for the effects of pharmaceuticals in the
environment, you need to ask what they’re going
to turn into.”
paper, “Transformation of Acetaminophen by Chlorination
Produces the Toxicants 1,4-Benzoquinone and N-Acetyl-p-benzoquinone
Imine” will appear in Environmental Science and Technology,
and is available from the journal’s ASAP Web site http://pubs.acs.org/journals/esthag/index.html.
and Standards Issues in Nanobiotechnology
National Institute of Standards and Technology (NIST) will co-host
a workshop to discuss needed measurement technologies and standards
in the rapidly evolving field of nanoscale biotechnology at Rice
University (Houston, Texas) on Jan. 19, 2006.
of nanotechnology—with its focus on synthesizing materials
and devices, and controlling their properties on an atomic scale—and
biotechnology has opened up a broad landscape of potential applications
and issues in medicine, basic research, manufacturing, and materials
science. Nanoparticles and nano-structured materials are being
studied for new methods of drug delivery and targeting therapeutic
agents, for improving contrast and detection levels in medical
imaging, and for basic research on the structure and dynamics
of biomolecules. Manufacturers studying nanotechnologies are concerned
with basic issues of safe materials handling and scale-up.
workshop will seek to identify the most critical measurement and
standards needs in this diverse and important new area of technology.
The U.S. Measurement System (USMS) Workshop on Measurement and
Standards Needs in NanoBiotechnology is sponsored by NIST, The
Alliance for NanoHealth, Battelle, Richard E. Smalley Institute for Nanoscale Science and Technology (Rice), Center for Nanoscale Science and Technology
(Rice), the departments of Defense and Energy, BioHouston, Environmental
Protection Agency, ASTM International, Gulf Coast Consortium,
Food and Drug Administration, Office of Naval Research, National
Cancer Institute, Nanotechnology Characterization Laboratory (NCI),
and Ben Franklin Technology Partners of Pennsylvania.
information is available at http://cohesion.rice.edu/centersandinst/cnst/conference.cfm.
There is a $50 registration fee.
is one of a series on the U.S. Measurement System (USMS) sponsored
by NIST to assess and document the nation's priority measurement
and measurement-related standards needs for technological innovation,
U.S. industrial competitiveness, safety and security, and quality