Thursday, March 31, 2005
Wednesday, March 30, 2005
Sunday, March 27, 2005
Plants Defy Mendel's Inheritance Laws, May Prompt Textbook Changes
What is this world coming to??? Is nothing sacred?? Plants Defy Mendel's Inheritance Laws, May Prompt Textbook Changes
Saturday, March 26, 2005
Albert Einstein on CD from the British Museum
Also contains a few Real Audio clips of the great man. Publications
Wednesday, March 23, 2005
Tuesday, March 22, 2005
Thursday, March 17, 2005
Tuesday, March 15, 2005
Cosmic Background Map Wrong??
The cosmic microwave background is often
called the echo of the Big Bang, but recent
research suggests that some of its features
might have their origins much closer to
home. Although most cosmologists think
that the tiny variations in the temperature of
the background are related to quantum fluctuations
in the early universe, Glenn Starkman
and colleagues at CERN and Case
Western Reserve University in the US have
now found evidence that some of these variations
might have their roots in processes
occurring in the solar system. If correct, the
new work would require major revisions to
the standard model of cosmology.
The cosmic microwave background was
formed about 380 000 years after the Big
Bang, when the expanding universe had
cooled enough for electrons and protons to
form hydrogen atoms. In the early universe
these electrons scattered the radiation created
in the Big Bang, but when this scattering
stopped, the density distribution of the
universe at the time became imprinted as
tiny fluctuations in the temperature of the
microwave background.These variations in
density eventually became the large-scale
structure of galaxies and clusters of galaxies
that we see in the universe today.
The detection of fluctuations in the cosmic
background by the COBE satellite in
1992 was a milestone in the history of cosmology,
and subsequent experiments – notably
the Wilkinson Microwave Anisotropy
Probe (WMAP), which was launched in
2001 – have measured the background in
more and more detail. Cosmologists plot the
magnitude of these fluctuations as a function
of the angle they subtend across the sky,
with different angular scales like musical
harmonics, each with a different frequency.
The lowest harmonic is almost entirely due
to the Doppler-shifted motion of the solar
system through the universe: the microwave
radiation is very slightly hotter in the direction
in which the solar system is moving
and cooler in the reverse direction.This “dipole”
harmonic has a hot spot at one end of
the sky and a cold spot at the opposite end.
In analysing their data, physicists working
on the WMAP mission have to subtract this
radiation from the rest of the signal so that
they are left only with the temperature fluctuations
created at the time of the Big Bang.
But Starkman and colleagues have found
strong evidence that the second harmonic,
the “quadrupole” (two hot spots and two
cold spots), and the third, the “octopole”
(three hot and cold spots) also have their
origins in the solar system. When they combined
the fluctuations from the quadrupole
and the octopole on the map of the sky, they
found that the plane of the solar system
threads itself through the resulting hot and
cold spots (see image), suggesting a link between
the orientation of the solar system and
the formation of these temperature fluctuations
(2004 Phys. Rev. Lett. 93 221301).
Other results appear to support this suggestion.
For example, the relative magnitude
of temperature differences in opposite
halves of the sky is greatest when the sky is
divided up along the plane of the solar system.
Starkman estimates that the odds of all
of these different pieces of evidence being a
fluke are anything up to a million to one.
“Each of these correlations could just be
an accident,” says Starkman. “But we are
piling up accident on accident. Maybe it is
not an accident and, in fact, there is some
new physics going on.”
What might this new physics be, assuming
there is not some subtle misunderstanding
of the WMAP instrument? The first possibility,
according to Starkman, is that the
solar system has some previously unknown
property, or contains additional matter that
can emit or absorb microwaves. Second, he
says, cosmologists might have to revise the
generally accepted idea that the very early
universe underwent a period of extremely
rapid expansion, known as inflation, just
after the Big Bang. The inflationary model
predicts fluctuations in the microwave background
of about the size found by WMAP
(in fact, slightly larger), so subtracting the
foreground contribution from the solar system
would leave this model wanting.
Charles Bennett of NASA’s Goddard
Space Flight Center,who is WMAP’s principal
investigator, is cautious about their conclusions.
“While the a priori probability of the
alignments [between solar system and temperature
fluctuations] is low, the alignments
are seen as a result of an a posteriori selection,”
he says. “So their significance is uncertain.”
But Pedro Ferreira, an astrophysicist at
Oxford University, says he would be surprised
if there were no local contributions
to the microwave background. “The data
we have on our galaxy are not as precise as
those produced by WMAP,” he says. “Which
means that we cannot really take the WMAP
data, use another accurate map to remove
the effect of the galaxy and see what is left.
To some extent we have to guess.”
Edwin Cartlidge
P H Y S I C S W O R L D J A N U A R Y 2 0 0 5 5
Doubts cast over map of cosmos
p h y s i c s w e b . o r g
Local effect? – astrophysicists have found that the
plane of the solar system (dashed line) threads
itself through hot and cold spots (circles) in the
cosmic microwave background, suggesting that
some of the variations in the latter are not caused
by events that took place in the early universe.
A collaboration of physicists from six
European countries and the US has been
awarded part of the European Union’s
Descartes research prize for work on
quantum cryptography. The IST-QuComm
collaboration consists of research groups
in Sweden, Germany, France, Switzerland,
Austria and the UK, plus a team from the
Los Alamos National Laboratory in the US.
They share the 71m prize with life scientists
studying mitochondrial DNA.
Quantum cryptography allows two parties
to share a secret “key” – encoded with
single photons – so that they can
communicate much more securely than is
possible with existing cryptographic
techniques. Any attempts by a third party to
eavesdrop on the communications can be
readily detected. Quantum cryptography
could have applications in everything from
electronic communications to e-banking
and e-voting. The IST-QuComm consortium
last year performed the first ever quantum
cryptographic bank transfer over a 6km
fibre-optic link in Vienna.
Meanwhile, Wolfgang Heckl, who is
director general of the Deutsches Museum
in Munich, has been awarded the first ever
Descartes prize for professional scientists
involved in science communication. He was
given the 750000 prize for his ability to
explain complex scientific topics in a simple
manner. Heckl, who appears regularly in the
German media, was previously a physicist at
the Ludwig Maximilans University in
Munich, where he ran a centre for
nanobiotechnology. He joined the museum
last October (see page 60).
Belle Dumé and Matin Durrani
Quantum-cryptography research scoops Descartes prize
AWARDS
NEWS
called the echo of the Big Bang, but recent
research suggests that some of its features
might have their origins much closer to
home. Although most cosmologists think
that the tiny variations in the temperature of
the background are related to quantum fluctuations
in the early universe, Glenn Starkman
and colleagues at CERN and Case
Western Reserve University in the US have
now found evidence that some of these variations
might have their roots in processes
occurring in the solar system. If correct, the
new work would require major revisions to
the standard model of cosmology.
The cosmic microwave background was
formed about 380 000 years after the Big
Bang, when the expanding universe had
cooled enough for electrons and protons to
form hydrogen atoms. In the early universe
these electrons scattered the radiation created
in the Big Bang, but when this scattering
stopped, the density distribution of the
universe at the time became imprinted as
tiny fluctuations in the temperature of the
microwave background.These variations in
density eventually became the large-scale
structure of galaxies and clusters of galaxies
that we see in the universe today.
The detection of fluctuations in the cosmic
background by the COBE satellite in
1992 was a milestone in the history of cosmology,
and subsequent experiments – notably
the Wilkinson Microwave Anisotropy
Probe (WMAP), which was launched in
2001 – have measured the background in
more and more detail. Cosmologists plot the
magnitude of these fluctuations as a function
of the angle they subtend across the sky,
with different angular scales like musical
harmonics, each with a different frequency.
The lowest harmonic is almost entirely due
to the Doppler-shifted motion of the solar
system through the universe: the microwave
radiation is very slightly hotter in the direction
in which the solar system is moving
and cooler in the reverse direction.This “dipole”
harmonic has a hot spot at one end of
the sky and a cold spot at the opposite end.
In analysing their data, physicists working
on the WMAP mission have to subtract this
radiation from the rest of the signal so that
they are left only with the temperature fluctuations
created at the time of the Big Bang.
But Starkman and colleagues have found
strong evidence that the second harmonic,
the “quadrupole” (two hot spots and two
cold spots), and the third, the “octopole”
(three hot and cold spots) also have their
origins in the solar system. When they combined
the fluctuations from the quadrupole
and the octopole on the map of the sky, they
found that the plane of the solar system
threads itself through the resulting hot and
cold spots (see image), suggesting a link between
the orientation of the solar system and
the formation of these temperature fluctuations
(2004 Phys. Rev. Lett. 93 221301).
Other results appear to support this suggestion.
For example, the relative magnitude
of temperature differences in opposite
halves of the sky is greatest when the sky is
divided up along the plane of the solar system.
Starkman estimates that the odds of all
of these different pieces of evidence being a
fluke are anything up to a million to one.
“Each of these correlations could just be
an accident,” says Starkman. “But we are
piling up accident on accident. Maybe it is
not an accident and, in fact, there is some
new physics going on.”
What might this new physics be, assuming
there is not some subtle misunderstanding
of the WMAP instrument? The first possibility,
according to Starkman, is that the
solar system has some previously unknown
property, or contains additional matter that
can emit or absorb microwaves. Second, he
says, cosmologists might have to revise the
generally accepted idea that the very early
universe underwent a period of extremely
rapid expansion, known as inflation, just
after the Big Bang. The inflationary model
predicts fluctuations in the microwave background
of about the size found by WMAP
(in fact, slightly larger), so subtracting the
foreground contribution from the solar system
would leave this model wanting.
Charles Bennett of NASA’s Goddard
Space Flight Center,who is WMAP’s principal
investigator, is cautious about their conclusions.
“While the a priori probability of the
alignments [between solar system and temperature
fluctuations] is low, the alignments
are seen as a result of an a posteriori selection,”
he says. “So their significance is uncertain.”
But Pedro Ferreira, an astrophysicist at
Oxford University, says he would be surprised
if there were no local contributions
to the microwave background. “The data
we have on our galaxy are not as precise as
those produced by WMAP,” he says. “Which
means that we cannot really take the WMAP
data, use another accurate map to remove
the effect of the galaxy and see what is left.
To some extent we have to guess.”
Edwin Cartlidge
P H Y S I C S W O R L D J A N U A R Y 2 0 0 5 5
Doubts cast over map of cosmos
p h y s i c s w e b . o r g
Local effect? – astrophysicists have found that the
plane of the solar system (dashed line) threads
itself through hot and cold spots (circles) in the
cosmic microwave background, suggesting that
some of the variations in the latter are not caused
by events that took place in the early universe.
A collaboration of physicists from six
European countries and the US has been
awarded part of the European Union’s
Descartes research prize for work on
quantum cryptography. The IST-QuComm
collaboration consists of research groups
in Sweden, Germany, France, Switzerland,
Austria and the UK, plus a team from the
Los Alamos National Laboratory in the US.
They share the 71m prize with life scientists
studying mitochondrial DNA.
Quantum cryptography allows two parties
to share a secret “key” – encoded with
single photons – so that they can
communicate much more securely than is
possible with existing cryptographic
techniques. Any attempts by a third party to
eavesdrop on the communications can be
readily detected. Quantum cryptography
could have applications in everything from
electronic communications to e-banking
and e-voting. The IST-QuComm consortium
last year performed the first ever quantum
cryptographic bank transfer over a 6km
fibre-optic link in Vienna.
Meanwhile, Wolfgang Heckl, who is
director general of the Deutsches Museum
in Munich, has been awarded the first ever
Descartes prize for professional scientists
involved in science communication. He was
given the 750000 prize for his ability to
explain complex scientific topics in a simple
manner. Heckl, who appears regularly in the
German media, was previously a physicist at
the Ludwig Maximilans University in
Munich, where he ran a centre for
nanobiotechnology. He joined the museum
last October (see page 60).
Belle Dumé and Matin Durrani
Quantum-cryptography research scoops Descartes prize
AWARDS
NEWS
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