Planck satellite: Maps detail Universe's ancient light

A map tracing the "oldest light" in the sky has been produced by Europe's Planck Surveyor satellite. Its pattern confirms the Big Bang theory for the origin of the Universe but subtle, unexpected details will require scientists to adjust some of their ideas.

Map of the oldest light in the Universe.

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


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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 long wavelength 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.

"I would imagine for [most people] it might look like a dirty rugby ball or a piece of modern art," said Cambridge University's George Efstathiou, presenting the new picture here at Esa headquarters in Paris.

"But I can assure you there are cosmologists who would have hacked our computers or maybe even given up their children to get hold of this map, we're so excited by it."

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.

How Planck's view hints at new physics

Planck anomalies graphic
  • 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.

Temperature anomalies in Planck data Planck has confirmed the north/south differences and a "cold spot" in the data

One is the finding that the temperature fluctuations, when viewed across the biggest scales, do not match those predicted by the standard model. Their signal is a bit weaker than expected.

Planck's new numbers

  • 4.9% normal matter - atoms, the stuff from which we are all made
  • 26.8% dark matter - the unseen material holding galaxies together
  • 68.3% dark energy - the mysterious component accelerating cosmic expansion
  • The number for dark energy is lower than previously estimated
  • The new age - 13.82 billion years - results from a slower expansion
  • This is described by a value known as the Hubble Constant
  • It too is revised to 67.15 km per second, per megaparsec (3.2 million light-years)

There appears also to be an asymmetry in the average temperatures across the sky; the southern hemisphere is slightly warmer than the north.

A third anomaly is a cold spot in the map, centred on the constellation Eridanus, which is much bigger than would be predicted.

These features have been hinted at before by Planck's most recent predecessor - Nasa's WMAP satellite - but are now seen with greater clarity and their significance cemented.

A consequence will be the binning of many ideas for how inflation propagated, as the process was first introduced in the 1980s as a way to iron out such phenomena.

The fact that these delicate features are real will force theorists to finesse their inflationary solutions and possibly even lead them to some novel physics on the way.

"Inflation doesn't predict that it should leave behind any kind of history or remnant, and yet that's what we see," Planck project scientist Dr Jan Tauber told BBC News.

CMB - The 'oldest light' in the Universe

Detail of CMB data
  • Theory says 380,000 years after the Big Bang, matter and light "decoupled"
  • Matter went on to form stars and galaxies; the light spread out and cooled
  • The light - the CMB - now washes over the Earth at microwave frequencies
  • Tiny deviations from this average glow appear as mottling in the map (above)
  • These fluctuations reflect density differences in the early distribution of matter
  • Their pattern betrays the age, shape and contents of the Universe, and more and follow me on Twitter: @BBCAmos


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  • rate this

    Comment number 111.

    Is it a giant, cosmic mirror? I mean, one can discern the reflection of North America, South America, the Pacific and the Atlantic, and Africa at the lower right.

  • rate this

    Comment number 110.

    It would make beautiful wallpaper in a Mercator projection.

  • rate this

    Comment number 109.

    @ Captain Lort You say. ALL you non-believers will pay the price eventually, science is equivalent to the devil, distracting you from the faith.

    Remember that the next time you switch the heating on in the winter or need an operation in hospital, drive your car to work, get on a plane, use antibiotics, get a malaria jab, boil a kettle and ironically type nonsense on your laptop.

  • rate this

    Comment number 108.

    Why is it that every time we talk about cosmology we have to bring religion into it? Religion is a method by which you can scare people so that they do what they are told (hence the reason for inventing 'hell').

  • rate this

    Comment number 107.

    Keith95a: Er, the World is flat. We live on the surface of a sphere (finite but unbounded) - hence you only need two cartesian co-ordinates to state where you are (e.g. map references). Only if you get off the surface then will need a third co-ordinate.

    PS Wishing isn't science (or mathematics) :)

  • rate this

    Comment number 106.

    why did God wait 13.85 billion years before creating us ?

  • rate this

    Comment number 105.

    What puzzles me is that a black hole prevents light escaping. So one imagines a photon setting off directly away from the centre of mass but then being 'pulled back' by the gravitational field, like a ball thrown vertically from e.g the moon. So photons must be slowed down by gravity. QED, the speed of light isn't a constant so 'old' light MAY not have travelled as far as is being said. Discuss.

  • rate this

    Comment number 104.

    There are only two mistakes one can make along the road to truth; not going all the way, and not starting.

  • rate this

    Comment number 103.

    that's a map of the universe ?

    should have gone to specsavers mate..

  • rate this

    Comment number 102.

    What the colours mean? This is essentially a map of temperature across all directions of the sky. The blue areas are coldest while the red are hottest. As I recall the difference in temperature between the hottest and coldest are only a few hundred thousandth of a degree, which is one of the things that makes this such a stunning engineering achievment.

  • rate this

    Comment number 101.

    Enthronements making the headlines supporting the irrelevant mysticism and aggrandisement of religion. Yet, when we have a scientific discovery it is shunted off to the nether regions of the news. Surely we should be celebrating such exploration of the universe and scientific discoveries even if the average layman (including me) doesn’t fully understand the scope of the science. Science first!

  • rate this

    Comment number 100.

    @83 So then apparently expressing my faith is trolling! What a stupid statement to make! Almost as stupid as saying we are living in an age of discovery, we are living in an age were the devil is testing humanity to new limits with this 'science', and unfortunately we are lapping it up!

  • rate this

    Comment number 99.

    "Now is the time for science and the spirit of the universe (God if you like) to come together. - annieavatar"

    No, I reckon it's time for history and the Tooth Fairy to come together.

  • rate this

    Comment number 98.

    64. Captain Lort & 67. Danny
    Is anyone else getting the feeling that either these are troll posts just trying to wind people up, or the posts of the terminally mentally challenged.
    It seems the church has the default response of; Answers = the devils work, ignorance is gods work.

    If ignorance is the way forward why did god give us intelligence and a desire to learn?

  • rate this

    Comment number 97.

    For a beautiful lecture by Krauss on the origin of the universe and the role of the 'first light' in scientific discovery see below:

    As for religion - It's just the 'the emperor’s new clothes’. Anybody can see there is nothing there. Why don’t people believe in fairies the other old man with a beard? Well that would be silly….

  • rate this

    Comment number 96.

    @63 Pete1000: God is not an answer to "where did it all come from" because it raises the rather obvious question "well where did god come from then?"

  • rate this

    Comment number 95.

    @64 Can anyone take you seriously? I think you are trolling for sure. But do you understand the hypocrisy of a 'believer' commenting on a forum, from a computing device through the internet and various routers and servers mad possible by breakthroughs in science and calling science equivalent to the devil? I hope you do...

  • rate this

    Comment number 94.

    28.PH "Why all negatives for number 8"?

    Because it shows no sense of proportion. Many billions *are* spent on medical research each year (and many many more billions on more frivolous or destructive things). 500M spent over about 15 years is less than 1p a year per member of our species - a bargain for a flagship science experiment which changes our view of the entire universe!

  • rate this

    Comment number 93.

    "it is so complicated, so the ordinary man won't understand and won't be able to challenge these so called 'facts'"

    That's precisely why the Church murdered people for writing Bibles not written in Latin.

    Your phone works whether you understand microchips & how much you scoff at ideas you don't understand.

    Say what you like about scientists: We don't burn & kill people who don't agree with us.

  • rate this

    Comment number 92.

    Wow....... how amazing, a squashed Google Earth picture


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