Yup, it’s time for those “top 10” lists for 2008.  I don’t generally post other peoples’ lists here, but heck, this is one area where I know that I haven’t been paying close enough attention to know what’s important.  So here is an edited version of the Physics Findings for 2008 from Physics News.  Phil Schewe does such a great job with these, they’re a delight to read.  You can read the whole thing at Physics News Update (and subscribe to their e-newsletter).

TOP TEN PHYSICS STORIES OF THE YEAR

The following list was chosen by editors and science
writers at the American Institute of Physics and the American Physical
Society.  It winnows a wealth of discoveries into the following ten
topic areas, which are listed in no particular order.

SUPERCONDUCTORS

What’s new-discovery of an unusual class of materials made from iron
and arsenic.   Superconductors don’t lose any energy when electricity
runs through them, providing they’re chilled to very low temperatures.
Superconductors are used in specialty applications where high
electrical currents are needed, such as in MRI scanners at hospitals or
in the magnets used to steer particles at atom smashers.  …

The new iron-arsenic materials are the first relatively
high-temperature materials that remain superconducting above a
temperature of 50 K that don’t contain copper; the copper materials are
brittle.  Researchers hope that the iron-arsenic version might lead to
the more practical manufacture of superconducting wire.   Furthermore,
having a new class of materials to study should help theorists
understand how high-temperature superconductors work in the first
place.
Background: A summary of work in this area can be found at Physics
Today, May 2008
; APS survey of topic.

LARGE HADRON COLLIDER

large_hadron_collider1

What’s new—the LHC, the world’s largest scientific instrument,
started operations in September.  At this huge particle accelerator,
located underground near Geneva, Switzerland, two beams of protons, each
traveling at unprecedented speeds will be smashed together.  The goal is
to create exotic new particles that can’t be observed in any other way
except in the tiny fireball created by such violent collisions.  ….

Problems with some of the apparatus forced a premature shutdown
…  General operations should resume in summer 2009.
Background: a summary of the magnet malfunction which brought testing to
a halt in September and a timetable for operations are available here.

PLANETS

What’s new-planets orbiting distant stars have been imaged directly, and a host of interesting results have come back from spacecraft hovering near the planets in our own solar system.  Extrasolar planets, planets orbiting far-away stars, had been detected indirectly by watching what happens to the light coming from the star.  But now the glare of the star has been blocked sufficiently that the extrasolar planet itself could be imaged.  The Gemini, Keck, and Hubble telescopes provided pictures. Background summary here.

In our own solar system, at Mercury, the Messenger spacecraft  made  first-ever maps of large portions of the surface. At Saturn, the Cassini  craft found geysers near the south end of the moon Enceladus.    At Mars, measurements made by several craft strengthened evidence in favor of sub-surface glaciers outside the polar regions. Meanwhile, the Venus Express craft recorded pictures at several wavelengths, facilitating, among other things, a better knowledge of clouds on Venus.

QUARKS

What’s new-unusual combinations of quarks were observed for the first time.  Physicists believe that an atom consists of one or more electrons orbiting a central nucleus.  The nucleus, in turn, is made of protons and neutrons, and these particles are made of something still more elementary-quarks held together by gluons.  … One discovery consists of the sighting of nuclear particles containing rare “bottom” quarks.  Background here.

[See the full article at Physics News Update for more on these experiments   -geekgirl]

FARTHEST SEEABLE THING

What’s new-seeing a flash of light from 7 billion light years away.
One of the brightest of all celestial objects is gamma-ray bursters,
objects that emit immense amounts of gamma radiation, the highest-energy
form of light.  The brightest-ever gamma ray burster was observed by the
Swift satellite.   Since looking out into space is equivalent
to looking back in time, this flash would have been coming from a moment
when the universe was only half its present age.  Publication in Nature.

ULTRACOLD MOLECULES

What’s new-first ever accumulation of molecules in large numbers and
at a temperature near absolute zero.  Using lasers to slow a gas of
particles down to near stillness is by now a standard method for
measuring the subtle properties of atoms.  Steven Chu, nominated to be
the Secretary of Energy, won a Nobel Prize for pioneering this subject.
Cooling molecules in this same way is difficult since molecules, made of
two or more atoms, have complicated internal motions.  But this year
several labs succeeded in first cooling atoms and then, at a temperature
close to absolute zero, getting them to combine into molecules. …
Background at http://www.aip.org/pnu/2008/split/875-1.html; figure
http://www.aip.org/png/2008/306.htm; PRL text and overview at
http://physics.aps.org/articles/v1/24

DIAMOND DETECTORSdiamond

What’s new-getting little imperfections in diamond to tell us about
how atoms behave like tiny magnets.  Diamond is made of a cross-linking of carbon atoms.  If one
carbon atom is missing from this network, the empty hole, in combination
with a stray nitrogen atom, acts as a sort of strange molecule in the
middle of all those carbon atoms.  This “molecule” can light up like a
little LED when you shine laser light in.  This in turn, can be used to
measure extremely weak magnetism.  Possible applications include data
storage for computers or high-sensitivity detectors. … See news summary at
http://www.aip.org/pnu/2008/split/858-1.html.

COSMIC RAYS

What’s new-experiments settle one mystery and uncover others.  Cosmic
rays are super-high-energy particles whizzing through the cosmos.  When
they smash into our atmosphere the rays turn out mostly to be ordinary
particles, such as protons or electrons, but with energies thousands or
millions of times higher than particles speeded up at accelerators on
Earth. [See full Physics News Update article for new results — there are many!  -geekgirl]

LIGHT PASSES THROUGH OPAQUE MATTER

What’s new—getting light to behave in a new way. When light strikes
an opaque material like milk most of the radiation is scattered; little
of it passes through the sample.  But in an experiment at the University
of Twente in the Netherlands, much more of the light can be made to
traverse the scattering material if beforehand the wavefront of the
incoming light is shaped by special filters. Background summary.

MACROSCOPIC FEEDBACK COOLING

What’s new—Scientists at the AURIGA lab in Padova, Italy have cooled
a one-ton aluminum bar to a temperature below 1 milli-kelvin using
special electrical circuits.  The bar is part of a detector designed to
measure passing gravity waves from space.  Using sensitive magnetic
sensors and feedback coils, the ringing of the bar (which is essentially
a large tuning fork) at one characteristic frequency was cooled from an
equivalent temperature of 4 K (the temperature of the bath of liquid
helium in which the bar sits) to a temperature of about 0.17 mK.  Lower
temperatures than this have been achieved with this feedback cooling
technique but only with much smaller masses.  Background: essay and PRL
article at http://physics.aps.org/articles/v1/3

Phillip F. Schewe

I almost never post any science news, but this one was big enough to make it over my radar, in part because of the webcasts that I did at the Exploratorium on Titan.

NASA CONFIRMS LIQUID LAKE ON SATURN MOON

titan_and_enceladus

titan_and_enceladus

PASADENA, Calif. — NASA scientists have concluded that at least one
of the large lakes observed on Saturn’s moon Titan contains liquid
hydrocarbons, and have positively identified the presence of ethane.
This makes Titan the only body in our solar system beyond Earth known
to have liquid on its surface.

Scientists made the discovery using data from an instrument aboard the
Cassini spacecraft. The instrument identified chemically different
materials based on the way they absorb and reflect infrared light.
Before Cassini, scientists thought Titan would have global oceans of
methane, ethane and other light hydrocarbons. More than 40 close
flybys of Titan by Cassini show no such global oceans exist, but
hundreds of dark lake-like features are present. Until now, it was
not known whether these features were liquid or simply dark, solid
material.

“This is the first observation that really pins down that Titan has a
surface lake filled with liquid,” said Bob Brown of the University of
Arizona, Tucson. Brown is the team leader of Cassini’s visual and
mapping instrument. The results will be published in the July 31
issue of the journal Nature.

Ethane and several other simple hydrocarbons have been identified in
Titan’s atmosphere, which consists of 95 percent nitrogen, with
methane making up the other 5 percent. Ethane and other hydrocarbons
are products from atmospheric chemistry caused by the breakdown of
methane by sunlight.

Some of the hydrocarbons react further and form fine aerosol
particles. All of these things in Titan’s atmosphere make detecting
and identifying materials on the surface difficult, because these
particles form a ubiquitous hydrocarbon haze that hinders the view.
Liquid ethane was identified using a technique that removed the
interference from the atmospheric hydrocarbons.

The visual and mapping instrument observed a lake, Ontario Lacus, in
Titan’s south polar region during a close Cassini flyby in December
2007. The lake is roughly 7,800 square miles in area, slightly larger
than North America’s Lake Ontario.

“Detection of liquid ethane confirms a long-held idea that lakes and
seas filled with methane and ethane exist on Titan,” said Larry
Soderblom, a Cassini interdisciplinary scientist with the U.S.
Geological Survey in Flagstaff, Ariz. “The fact we could detect the
ethane spectral signatures of the lake even when it was so dimly
illuminated, and at a slanted viewing path through Titan’s
atmosphere, raises expectations for exciting future lake discoveries
by our instrument.”

The ethane is in a liquid solution with methane, other hydrocarbons
and nitrogen. At Titan’s surface temperatures, approximately 300
degrees Fahrenheit below zero, these substances can exist as both
liquid and gas. Titan shows overwhelming evidence of evaporation,
rain, and fluid-carved channels draining into what, in this case, is
a liquid hydrocarbon lake.

Earth has a hydrological cycle based on water and Titan has a cycle
based on methane. Scientists ruled out the presence of water ice,
ammonia, ammonia hydrate and carbon dioxide in Ontario Lacus. The
observations also suggest the lake is evaporating. It is ringed by a
dark beach, where the black lake merges with the bright shoreline.
Cassini also observed a shelf and beach being exposed as the lake
evaporates.

“During the next few years, the vast array of lakes and seas on
Titan’s north pole mapped with Cassini’s radar instrument will emerge
from polar darkness into sunlight, giving the infrared instrument
rich opportunities to watch for seasonal changes of Titan’s lakes,”
Soderblom said.

Launched in Oct. 1997, Cassini’s 12 instruments have returned a daily
stream of data from Saturn’s system. The mission is a cooperative
project of NASA, the European Space Agency and the Italian Space
Agency.

For information on Cassini, visit:   http://www.nasa.gov/cassini

Here are some fantastic photos from the New Scientist website — accidentally captured the clearest picture of a woman’s ovary in the process of ovulation.

Pictures and articles here

I guess it’s pretty hard to get pictures of an event that happens for just a few minutes at one poorly determined time each month. They just happened to have this woman already cut open at the time (she was getting a partial hysterectomy). What luck. Apparently the main scientific result of the images is that the process happened much slower than previously thought — it took about 15 minutes for the egg to emerge.

I was actually just as interested to see the ovary and the follicle themselves (the follicle is *huge*!) as the emergence of the egg.

Hmm, a funny post for Father’s Day, I realize!

And, congratulations to me, I turn 100 today!  This is my 100th post…

Matthew Nisbett’s blog, Framing Science, just posted a note about a potential ban on nanotechnology in consumer products due to health concerns. He quotes a NY Times article in which nanotech is called the asbestos of tomorrow. He writes:

The asbestos comparison immediately places nanotechnology in the mental box of uncertainty and risky health impacts. For several years, consumer advocates have used asbestos as a familiar historical example to anchor interpretations of nanotech, but now this advocacy package has been given resonance by a study appearing this week in the journal Nature Nanotechnology. From the NY Times article

Emphasizing a regulatory vacuum, the advocacy group released a report this week calling for nanomaterials to be banned in foods and packaging, and for mandatory labeling in cosmetics, personal-care products and cleaning agents.

I commented:

I think a ban is an alarmist move. Not all nanotechnology is bad, nor is it all good. A while back a citizen group called for a warning label on all products containing nanotechnology. You can listen to an excellent audio essay by journalist Philip Ball on my podcast SmallTalk (a short-lived series on nanotechnology from the Exploratorium).

There is also some good discussion by the folks at the Woodrow Wilson institute on that podcast about the tricky issues facing consumer products using nanotechnology. It’s a regulatory issue, and one that needs to be done carefully because of the potential health risks, but the benefits of nanotech are potentially large.

Another blogger picked up on the NY Times story and had this to say:

There’s a new study reported in Nature Nanotechnology entitled “Carbon nanotubes introduced into the abdominal cavity of mice show asbestos-like pathogenicity in a pilot study.” Or, as the title seems to have been understood by reporters at the New York Times and elsewhere, “Blah NANO blah blah blah ASBESTOS blah PATHOGEN blah blah.

Even more interestingly, he points out that the study isn’t that substantive, and the inclusion of Andrew Maynard as a co-author may have been strategic:

Substantively, there isn’t much surprising about this study. Indeed, the authors basically say “toxicologists have a paradigm for how mesothelial cells respond to long, skinny, tiny fibers – and that paradigm seems to hold true for carbon nanotubes.” Their results aren’t very conclusive, or even all that dire, yet the study has gotten plenty of attention. Why? Well, for one thing, the study was pretty savvily designed to fit into ongoing policy debates about nano. One of the authors, for instance, is Andrew Maynard of the Woodrow Wilson Center for International Scholars in DC.

Now, Maynard is a bona fide expert in this area, but his current day job is at a Washington think tank. His contribution to the article doesn’t appear to have been technical, but rather he “provided intellectual input and contributed to the writing of the manuscript.” I’m guessing that means he helped the authors figure out how to position their research in relation to previous studies on nanotubes, and used the considerable media profile of the Wilson Center’s Project on Emerging Nanotechnologies to amplify their findings. It certainly looks like the Wilson Center primed science reporters to take a much keener interest in this study than they might normally.

There are certainly a lot of people with a stake in this debate. How it plays out in future years will be interesting.