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 51.

    I usually refrain from commenting on these things but it's just too much!

    People can have faith and belief in whatever they choose however you can't just ignore evidence based on the fact that you don't like what it says or are unable to understand it. This is an extremely ignorant and dangerous thing to do, please open your eyes!

  • rate this

    Comment number 50.

    Kindly complete your story by telling your viewers what the particular colors mean. Thank you.

  • rate this

    Comment number 49.

    Surely the question which arrises from your question is "why does there have to be a reason for everything?"
    There's no solid evidence that anything has a purpose and if it did, who's to say that purpose is 'to support human life'?
    Just playing a little Devil's advocate...

  • rate this

    Comment number 48.

    Just looks like a lot of dots to me.. Haven't we got better things to do?

  • rate this

    Comment number 47.

    "How do you tell how old light is ?"

    Bits of light can't be examined and dated.
    But we can see how far it has travelled and compare that to the speed of light.
    The frequency is not a factor. The frequency does though become lower ('red-shift') if the emitting object is travelling away from you, just like the sound of a train deepens as the train travels away. The inverse is also true(blue-shift)

  • rate this

    Comment number 46.

    Incredible. But I still want to know what was there before the universe was created...

  • rate this

    Comment number 45.

    I dont understand why these items attract religious zealots (I include atheist zealots).

    Amazing piece of work. An open and enquiring mind is what's best, surely. (along with some respect for other's opinions, whatever they may be)

  • rate this

    Comment number 44.

    28. PH

    When the natural resources present in mother earth are used - and we need to utilize resources from other worlds then it might, it just might be wise to have a better idea about our environment in a wider sense and how to get there a little more quickly than is currently the case.

    Does that explanation suffice?

  • rate this

    Comment number 43.

    @14 Captain Lort - the idea that everything can only be true if it is readily understandable by the layman makes no sense. Neither does restricting your thinking about the universe into the variable translation and selective editing of Iron age man's scribblings into 800 English words

    @8 Milton - indeed it was. Billions are spent on heart disease and Cancer Research each year.

  • rate this

    Comment number 42.

    @6 The point is that there is a background of noise from random chemical processes right across the EM spectrum, but there is a huge spike at the frequency corresponding to 2.7 degrees that cannot be explained by chemistry, but fits theory precisely for a big bang universe of the age, density and composition of the sort we seem to find ourselves in.

  • rate this

    Comment number 41.

    Amazing. Utterly amazing. Well done!!!

  • rate this

    Comment number 40.

    @14 "The universe and all it's contents were created by god in 7 days".

    Really? where do you find that information? "because it said so in a book, init?" has anyone actually investigated such a claim to see if there is any evidence to back up such a theory? No! The beauty of science is people are questioning all the time. Religious belief is never questioned. The earth was "flat" once you know.

  • rate this

    Comment number 39.

    Just so interesting! If we had a big bang, What was the n-1th step prior to the big bang, was it the big hold, where everything was help in a great mass. Could be. Or maybe there was a dense mass at the core or maybe had several cores with elements floating around. Then something exploded moving things apart. What if it all moves together. All not exactly clear but so fascinating.

  • rate this

    Comment number 38.

    I have a Big Bang occasionally, but the light never seems to get anywhere other than flashing in my eyes... hey ho... back to the drawing board.
    Maybe scientists can do some research into why scientists research the depths of the Universe to find useless information that isn't going to change my Big Bang theory!

  • rate this

    Comment number 37.

    It says a lot about our society that if you say Big Bang Theory to 99% of the population, they are more likely to think TV show than creation of the universe.

  • rate this

    Comment number 36.

    And yet we have had the new leader of a superstitious order on the news all week who believes his God is preoccupied with stopping people using lifesaving contraceptives. What an odd world of extremes we are.

  • rate this

    Comment number 35.

    I get a similar picture if I pull the ariel out of my TV and it doesn't cost half a £billion !

  • rate this

    Comment number 34.

    I imagine the Plank Surveyor Satellite would find high densities of dim matter in many parts of the UK.

    For the critics of the cost, how much money / resource is spent on deciphering / understanding / teaching of religious texts / theories...which could be channelled into science and the good of mankind instead..?

    Knowledge is only of use to those who want to understand.

  • rate this

    Comment number 33.

    Oh yes we should not question anything and all live by a set of rules laid down by someone talking to a burning bush.....

  • rate this

    Comment number 32.

    Nice picture, which way is North?


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