Astronomical Theory and Observation Unite to Tap Early Universe for Secrets of Fundamental Physics

PureInsight | May 25, 2008

Aim to produce new generation of astronomer that understands theory and observation

The future of fundamental physics research lies in observing the early
universe and developing models that explain the new data obtained. The
availability of much higher resolution data from closer to the start of
the universe is creating the potential for further significant
theoretical breakthroughs and progress resolving some of the most
difficult and intractable questions in physics. But this requires much
more interaction between astronomical theory and observation, and in
particular the development of a new breed of astronomer who understands

This was the key conclusion from a recent workshop organised by the
European Science Foundation (ESF), bringing together experts in
cosmology, astrophysics and particle physics. "I think the realization
of how important this is, and of how much needs to be done to get to
that stage, will be the main long-term legacy of the workshop," noted
Carlos Martins, convenor of the ESF workshop. "In particular, a lot of
work needs to be done in order to provide a stronger 'theoretical
underpinning' for future observational work. Ultimately this means that
when training the next generation of researchers in this area, a lot
more effort needs to be put into forming 'bilingual' researchers, that
are fluent both in the language of observations and in that of theory."

In effect astronomy is returning to its roots, since the early great
discoveries were made by the likes of Galileo for whom theory and
observation were two sides of the same coin. The field subsequently
split into two, with theorists and observers becoming divorced and
ceasing to communicate effectively with each other. Now though the
emergence of highly sophisticated observing platforms, capable of
making different types of measurement depending on theoretical
considerations, means that the two are once again becoming closely

Two key developments are the ability to take the observing instruments
into space, where more accurate observations can be made beyond the
influence of the earth's atmosphere and magnetic field, and
availability of high precision atomic clocks for measurement of timing
down to nanoseconds. At the same time it has become clear there is a
limit to how much can be discovered in earth-bound laboratories, even
those as big as the Large Hadron Particle Accelerator run by CERN, the
European Organization for Nuclear Research, in Switzerland. The early
universe on the other hand is a natural laboratory with the required
scale and energy, providing the potential for probing deeper into
fundamental processes relating to matter and energy. "The idea was to
bring together the top European expertise in cosmology, astrophysics
and particle physics, get the various sub-communities to be aware of
what is being done 'elsewhere', and focus our efforts on using the
early universe as a laboratory in which we can probe fundamental
physics - in ways that we'll never be able to do if we restrict
ourselves to laboratory tests," said Martins.

The workshop also discussed some of the fundamental questions that
these new observations could help resolve, notably whether or not
scalar fields exist across the whole the universe. Unlike say
gravitational or magnetic fields, which have both strength and
direction, scalar fields have strength alone, varying from point to
point. They definitely exist within some closed systems, such as the
temperature distribution within the earth's atmosphere, but it is not
yet known whether they exist on the scale of the universe. As Martins
pointed out, this is a vital question because the existence of scalar
fields could help explain how the universe developed after the Big Bang
and became as we observe it today. For example scalar fields could
explain the existence of dark matter and energy, which can only be
observed indirectly from their gravitational effects on the part of the
universe we can see.

New observations could also help confirm aspects of current theories,
such as the existence of gravitational waves as predicted by Einstein's
General Relativity. Gravitational waves are supposed to be ripples
through space time radiating outwards from a moving object. However the
ripples are so small as to be very difficult to measure, with the only
observational evidence so far coming from pulsars, which are very dense
binary neutron stars revolving around each other. The revolution of
pulsars appears to slow down in a manner consistent with the existence
of gravitational waves causing them to lose energy, but further
confirmation is needed.

Finally there is also the prospect of making further progress in the
field of astronomy itself, for example by using space borne atomic
clocks to calibrate advanced spectrographs that in turn will be used to
search for "extra-solar" planets in neighbouring star systems.

The workshop, Astrophysical Tests of Fundamental Physics was held in March 2008 in Porto, Portugal.


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