TECH KNOWLEDGEY
EVENTS, ADVANCES, AND NEWS
2008
■ BY JEFF ECKERT
ADVANCED TECHNOLOGY
Things are Looking Up...
■ This Chandra image shows our
Galaxy’s center, with the arrow aimed
at Sagittarius A*. Credit: NASA/CXC
/MIT/Frederick K. Baganoff et al.
Black holes are pretty well
accepted as fact these days. After
all, they were theorized as early as
1783 by Rev. John Michell, an
amateur English astronomer. They
are described by the general theory
of relativity, have a definable event
horizon at the outer edge, and may
last forever. (However, when quantum theory is taken into account,
they may actually leak thermal
energy [Hawking radiation] and may
have a finite life. But I digress.)
For Capt. Jean-Luc Picard, black
holes were more common than fleas
on a Clingon, so they must be real.
The only snag is that no one has
actually proven their existence. For
obvious reasons, it’s impossible to
see one, but at least you can observe
its effects — if you can get a ringside
seat, that is.
Space gases and solid objects
heat up as they are pulled closer to
the event horizon, so you can learn
some things about the black hole
from the resulting glow. As it turns
out, this one let out a mysterious
12 November 2008
major flare about 300 years ago
but has been relatively dormant
ever since.
Well, astronomers at the MIT
Haystack Observatory are busy
peeping in, and the latest observation
tool is a “virtual telescope” that they
created by linking radio dishes located in Hawaii, Arizona, and California.
The resulting device measures 28,000
miles ( 45,000 km) across and, —
because its angular resolution enables
a technique known as very long baseline interferometry — can generate
images 1,000 times as fine as those
of the Hubble Space Telescope. The
current focus is on the glowing region
of Sagittarius A* (pronounced
“A-star”), a suspected black hole that
resides in the center of our own Milky
Way. A* is a jumbo, containing about
four million times the mass of the
Sun. New observations have been
made using 1.3 mm radio waves,
which can penetrate the fog of
interstellar gas that blurs observations
at longer wavelengths, and they have
revealed the highest density yet for
the concentration of matter at the
center of our galaxy.
The astronomers concluded that
the source of the radiation likely
originates with either a disk of matter
swirling in toward the black hole or a
high speed jet of matter being ejected
by it. This “is important new evidence
supporting the existence of black
holes,” according to MIT’s Sheperd
Doeleman. “Future observations that
create even larger virtual telescopes
will be able to pinpoint exactly what
makes Sagittarius A* light up.”
...and Down
Since it was introduced commercially in the 1960s, the scanning
electron microscope (SEM) has been
pretty much the cat’s meow for
nanoscale measurement. But last
summer, Carl Zeiss, Inc. (www.zeiss.
com), delivered the first helium ion
microscope to the National Institute
for Standards and Technology (NIST,
nist.gov). Dubbed “Orion,” it will be
used for improving production in the
semiconductor and nanomanufactur-ing industries. The new microscope
uses helium ions to generate the
signal used to image extremely small
objects, which is similar to the way an
SEM works. Paradoxically, although
helium ions are much larger than
electrons, they can provide higher
resolution, higher contrast images.
According to Bill Ward, the
instrument’s principal inventor,
“Because the Orion ion beam
appears to be emanating from a
region which is less than an angstrom
in size, the resulting ion beam has a
remarkable brightness. This makes it
possible to focus the beam into a
very small probe size. Ultimately,
this microscope will enable further
scientific advancements in a large
number of fields, such as semiconductor process control, life science
applications, and materials analysis.”
Zeiss has already replaced the
original Orion with the Orion Plus,
which incorporates many of NIST’s
suggestions in its design, including
an improved cooling system for the
■ An image of gold atoms on tin
from a scanning electron microscope
(left) has relatively poor depth of
field. By contrast, the entire image
from a helium ion microscope image
(right) is sharp and clear. Credit: NIST.
