Nature:
The European Space Agency's €600 million ($775 million)
Planck
telescope, launched in 2009, has provided the most
detailed map of the
cosmic
microwave background (CMB) radiation yet. CMB radiation is
made of the photons that were first allowed to travel freely
when the universe cooled to the point that hydrogen and helium
atoms could form. Over time those photons have cooled to
temperatures of just 2.7 K.
Planck's mapâmdash;constructed from
more than 15 months of dataâmdash;is further
confirmation of the inflationary universe theory, which
explains the size of the universe and the structure of the
material within it. The new map has also refined the Hubble
constantâmdash;the rate of expansion of the
universeâmdash;down to 67.3 km/s/Mpc. That
makes the universe about 13.81 billion years old, slightly
older than previously estimated. More than three times as
sensitive as previous missions,
Planck detects variations in the CMB temperature of
just one millionth of a degree. It has also provided a more
accurate distribution of the energy density of the universe,
with dark energy reduced to 68.3% of the total, dark matter
increased to 26.8%, and normal matter amounting to less than
5%.
Planck's data also confirm an unusual asymmetry in the
distribution of CMB temperature, which rules out some of the
simpler models of inflation, but hints at the possibility of
new physics yet to be discovered.
