ESA Planck satellite: Maps detail Universe's ancient light

The map shows tiny deviations from the average background temperature, where blue is slightly cooler and red is slightly warmer. 

The cold spots are where matter was more concentrated and later collapsed under gravity to form stars and galaxies. 

Image: ESA/Planck Collaboration

A spectacular new map of the "oldest light" in the sky has just been released by the European Space Agency.

Scientists say its mottled pattern is an exquisite confirmation of our Big-Bang model for the origin and evolution of the Universe.
But there are features in the picture, they add, that are unexpected and will require ideas to be refined.

The map was assembled from 15 months' worth of data acquired by the 600m-euro (£515m) Planck space telescope.

It details what is known as the cosmic microwave background, or CMB - a faint glow of microwave radiation that pervades all of space.

Its precise configuration, visible in the new Planck data, is suggestive of a cosmos that is slightly older than previously thought - one that came into existence 13.82 billion years ago.

This is an increase of about 50 million years on earlier calculations.

The map's pattern also indicates a subtle adjustment is needed to the Universe's inventory of contents.

It seems there is slightly more matter out there (31.7%) and slightly less "dark energy" (68.3%), the mysterious component thought to be driving the cosmos apart at an accelerating rate.

Planck is the third western satellite to study the CMB. The two previous efforts - COBE and WMAP - were led by the US space agency (Nasa). The Soviets also had an experiment in space in the 1980s that they called Relikt-1.

• The CMB's temperature fluctuations are put through a number of statistical analyses
• Deviations can be studied as a function of their size on the sky - their angular scale
• When compared to best-fit Big Bang models, some anomalies are evident
• One shows the fluctuations on the biggest scales to be weaker than expected
• Theorists will need to adjust their ideas to account for these features

The CMB is the light that was finally allowed to spread out across space once the Universe had cooled sufficiently to permit the formation of hydrogen atoms - about 380,000 years into the life of the cosmos.

It still bathes the Earth in a near-uniform glow at microwave frequencies, and has a temperature profile that is just 2.7 degrees above absolute zero.

But it is possible to detect minute deviations in this signal, and these fluctuations - seen as mottling in the map - are understood to reflect the differences in the density of matter when the light parted company and set out on its journey all those years ago

The fluctuations can be thought of as the seeds for all the structure that later developed in the cosmos - all the stars and galaxies

Scientists subject the temperature deviations to a range of statistical analyses, which can then be matched against theoretical expectations.

This allows them to rule in some models to explain the origin and evolution of the cosmos, while ruling out a host of others.

The team that has done this for Planck's data says the map is an elegant fit for the standard model of cosmology - the idea that the Universe started in a hot, dense state in an incredibly small space, and then expanded and cooled.

At a fundamental level, it also supports an "add-on" to this Big Bang theory known as inflation, which postulates that in the very first moments of its existence the Universe opened up in an exponential manner - faster than light itself.

But because Planck's map is so much more detailed than anything previously obtained, it is also possible to see some anomalies in it.