EVENTS, ADVANCES, AND NEWS
■ BY JEFF ECKERT
DARK ENERGY SURVEY UNDERWAY
■ Image of the barred spiral galaxy NGC
1365 — about 60 million light years away.
Courtesy of Dark Energy Survey Collaboration.
This fall, scientists collaborating on the Dark Energy Survey down at Chile's Cerro Tololo Inter-American
Observatory switched on the 570 megapixel dark energy
camera for the first time and captured rays of light that
have been traveling from distant galaxies for some eight
billion years. The camera — said to be the most powerful
instrument of its kind — is designed to probe the mystery of
dark energy which is thought to be the force causing the
universe to expand at an ever-increasing rate. The camera
— which is about the size of a telephone booth — employs
a 13 ft diameter light-gathering mirror and 62 CCDs with
extreme sensitivity to red light.
The survey — beginning this month and continuing
over the next five years — will create detailed color images
of one-eighth of the sky (or 5,000 square degrees) to
discover and measure 300 million galaxies, 100,000 galaxy
clusters, and 4,000 supernovae. According to Argonne Labs physicist Steve Kuhlmann, "With all of our amazing scientific
progress in the last century, we still only understand the four percent of the universe that is made of normal matter. The
Dark Energy Survey will help us understand the other 96 percent, which we believe is made of dark matter and dark
energy." (Many of the camera's critical systems are controlled with Argonne-designed technology.) You can follow the
survey's progress at www.darkenergysurvey.org. ▲
10 December 2012
TRANSIENTS CAN BE GOOD
Electronic transients are usually undesirable things, but transient electronics are a different story, according to a team led by biomedical engineers at Tufts
University ( www.tufts.edu) and researchers at the University of Illinois at
Urbana-Champaign ( illinois.edu). These folks have developed a new class of
silk-silicon devices that should prove useful in medical implants, environmental
sensors, and a range of consumer electronics. For example, a medical implant
within a human body could function for its intended life span and then dissolve
away harmlessly, or consumer electronics such as cell phones could be built to
decompose quickly when dropped into a landfill instead of slowly deteriorating
for years. The time frame can range from minutes to years, depending on the mix
of fabrication materials.
The circuits use traditional IC materials such as silicon and magnesium, but
they are constructed in an ultra-thin form and are encapsulated in silk protein.
"These devices are the polar opposite of conventional electronics whose integrated
circuits are designed for long-term physical and electronic stability," noted Prof.
Fiorenzo Omenetto of the Tufts School of Engineering. "While silicon may appear
to be impermeable, eventually it dissolves in water." The trick is to fine-tune the
silk properties so the circuits dissolve at the right time.
In the future, the researchers are looking toward devices whose properties
can be adjusted in real time or that can respond to environmental factors such as
chemistry, light, or pressure. A paper detailing the concept published in the
September 28, 2012 issue of Science is available at firstname.lastname@example.org. ▲
■ Silk-silicon electrical circuit is
dissolved by a drop of water.