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 211.

    " should exist as a spherical wavefront about 14 bn light years in radius, and everything else (including us) should be inside it. How can we detect it?"

    Not all of those photons have to fly outwards. If you stand inside an explosion you will still see the light from it. And yes: We think we are inside an expanding universe. We lack the tools to be able to see the edge of it.
    Hope that helps

  • rate this

    Comment number 210.

    Fred Hoyle would have seen this as a map of continuous creation.
    There was no big bang, just a steady accumulation of matter injected from a higher dimension.
    This injection is is what we think of as dark energy.

  • rate this

    Comment number 209.

    This article actually is quite comforting for a christian. God has given man great intellect to search and explore the wonders of this universe. But trying to take the smallest possible chance (I mean really small, like 1/10000000000000000000000) that big bang is true is quite foolish.

  • rate this

    Comment number 208.

    Absolutely amazing. I'd love the opportunity to work on something like this. This sort or research is truly inspiring.

  • rate this

    Comment number 207.

    @ Dan
    sheesh, 68% isnt the error! the old figure was 73% . and I thought was a pleb

  • rate this

    Comment number 206.

    As an astrophysics graduate my only grouse with the article is the statement that these findings CONFIRM the Big Bang theory of the origin of the Universe. The evidence SUPPORTS the theory would be a much safer and more sensible scientific statement in my view. I personally reserve judgement in case one day another Einstein comes along with a radical and altogether more satisfactory explanation.

  • rate this

    Comment number 205.

    Interesting stuff that may one day help answer some real questions. Until then I can't help but feel we're as clueless as ants when it comes to solving the mystery of 'the beginning' 'the end' 'why?' or anything else. Speculation about 'Standard' models is just 'having a bit of a guess' really.
    And the reason the bottom half is warmer is because that's where the monster sleeps. Shsh!

  • rate this

    Comment number 204.

    No, these are the revised figures. It's thought to be a 68/32 split now - however the original figures should of been stated by the reporter so as not to confuse people who can't figure this out for themselves.

  • rate this

    Comment number 203.


    I would like to link you to Carl Sagan about the exact same thing you ask.. It cannot be explain better by anyone else as of yet

  • rate this

    Comment number 202.

    @192 ah

    Great get-out clause; the old debate over what the bible actually says and the many possible interpretations. Conveniently vague, one might say. Or just poorly written trash. Probably a bit of both.

    The bible does not "support" any scientific reason as it is a work of fiction, and therefore incapable of being cited in any kind of "supportive" capacity.

  • rate this

    Comment number 201.

    The trouble with science is that it is constantly in a state of becoming out of date. Science never "proves" anything; rather it continually finds, or fails to find, support for its current paradigm. When that paradigm is found wanting, the "findings" of science shift to accommodate the new data. This is why science is quite unlike things like poetry, whose "truth" or value doesn't ever change.

  • rate this

    Comment number 200.

    For those of you who think it looks a bit like a map of the Earth, this is a psychological artefact caused by spurious 'pattern recognition' - we human beings are extremely good at pattern recognition, to the extent we see them when they are not actually there!

  • rate this

    Comment number 199.

    Do people who dismiss religion also dismiss spirituality in general? Soul, etc? or just organised views? Before you say science is eveything you really should consider what that means in terms of your own existence.

  • rate this

    Comment number 198.

    Fascinating stuff, and I studied astronomy at university. However, I'm cautious when the big bang theory is portrayed as proven. It is assumed that the redshift in light from galaxies has to be due to them moving away from each other, hence expansion of the Universe. That may be true, but I like to be open to other possibilities. The Universe is vaster than all our ideas and systems of thought.

  • rate this

    Comment number 197.

    @145.just kidding
    Try "Plasma Universe" (Alfvén-Klein cosmology)

    And, please, stop worshiping Einstein idol. He was a mediocre mathematician, horrible physicist and a brilliant plagiarist. His cult worshiped for the last 60 years is ridiculous. Einstein stole most of his ideas for special relativity from Lorentz and Poincaré.

  • rate this

    Comment number 196.

    Sorry to repeat myself. But if people would like to understand the origin of the Universe including; dark matter, dark energy, first light, how zero point energy enables the universe to start from nothing and so on. See the lecture by Krauss. It is enthralling. (just skip the into by Dawkins)

  • rate this

    Comment number 195.


    Anyone know what happened before the big bang?

    All that matter and energy must have come from somewhere.
    Google "A Universe from Nothing", and view a great youtube talk by Lawrence Krauss.

  • rate this

    Comment number 194.

    188 ichabod - There is a school of thought that there was no "before" the Big Bang, as time only came into existence along with the Big Bang.

    It's a difficult concept for our primative little monkey brains!

  • rate this

    Comment number 193.

    'Faster than light itself' - Wow!

    And what on earth is that cold spot? Fascinating...

    If Planck was NASA's they would have started the presentation with 'A great day for Americans...' - what's the money that ESA did NOT start their presentation today with 'A great day for Europeans...' ???

    This is a wonderful achievement for Humanity, just wish we all saw it that way.

  • rate this

    Comment number 192.

    To any people commenting that the Bible says the earth is 6000 years old, it does not. The Bible supports the big bang, in actual fact. There was a beginning, there is continual expansion, there are constant laws of physics and a law of decay, all stated or alluded to in the Bible. Promulgating these ideas leads people to think it's science or religion, which is untrue.


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