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 171.

    148. juventus18
    "As PROVED by the bible, the earth is 6,000 years old."

    In the same week as when Obama goes to Israel, this sort of viewpoint is why a large number of people (Chritian fundamentalists) believe that Palestinians have no rights in the Middle East as part of their belief is the Rapture.

    But this research by the Euorpeans of the CMB (and previous by USA & Soviets) is fascinating

  • rate this

    Comment number 170.

    And there was the BBC thinking the light shown out of their....

  • rate this

    Comment number 169.

    Just for reference - the massive irony is that Captian Lort (the real one) sailed on the Beagle with Charles Darwin, thusly giving mere mortals the information to discredit the watchmaker theory. Hilarious.

    Amazing news, keep on keeping on!

  • rate this

    Comment number 168.

    So what was there before the big bang?

  • rate this

    Comment number 167.


    "As PROVED by the bible, the earth is 6,000 years old. This is FACT and discoverable for anyone who picks up the Holy Book. ,,, Open The Book and discover the TRUTH"

    The same book that condones genocide, slavery and the oppression of women. God? Incompetent, impotent, uncaring or downright malign. Take your pick.

  • rate this

    Comment number 166.

    I wonder if Mr Amos is tired of everytime he opens a forum on his columns, he is constantly bombarded by insane ignorant religious fools. Free Speech is great, but the same crazies over and over. Thankfully there are more intelligent people commenting too. No wonder scientists like Richard Dawkins and Lawrence Krauss are publically vocal about it. Well done sirs.

  • rate this

    Comment number 165.

    "Slightly more" matter 32%, "slightly less" dark energy 68%
    Talk about putting a positive spin on calculations that are WAY OFF

    I really don't see how a 68% error can be described as slight but at least the map still supports the big bang theory, it needs all the support it can get these days.

  • rate this

    Comment number 164.

    132. MGary
    To call a theory stupid is rather preemptive. What published papers have you read that come up with such a claim? Other theories are out there, but none have been proven or have disproven big bang..yet.
    This research supports big bang, but does not prove it conclusively (bad journalism). What research leads you to think it is stupid?
    Or is it you just don't understand it, so dismiss it?

  • rate this

    Comment number 163.

    There is some research into the what is seen as the CMB is not in fact the Big Bang CMB but something more local (proper research not fringe) but far from proved.

    Until proved you uphold the current theory, which i do (as above).

    Why do people recite out dated victorian religous doctrine - science was once an important facet of religion until it got scared of change and risk its power.

  • rate this

    Comment number 162.

    @116 Phil

    "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."

    The radiation of the CMB did not occur at the moment of the big bang, but long afterwards when light and matter separated. By this point the mass of the universe was distributed.

  • rate this

    Comment number 161.

    Of course, Bible is a collection of Jewish fairy tales. Grown up people should not believe fairy tales. Modern cosmology is largely a fairy tale too. There was no "Big Bang". Hubble, who 1st observed "red shift" of galaxies did not believe it was caused by their "running away from each over". Prove that "Hubble Law" is wrong:

  • rate this

    Comment number 160.

    @128 Damo

    Silly statement. What if you are wrong and the Romans were right?

    Trouble with religion (blind belief) is that there is an infinite number of them. But, there is only one correct scientific understanding.

  • rate this

    Comment number 159.

    As Science states we can only see and measure 5% of the known Universe so I think is questionable to assume an age for it with so little. 13.86 Billion yeas is for the part we can see... Can we state an age 20 times bigger for the part cannot if we make a proportion between size and age ?

  • rate this

    Comment number 158.

    Rather than a press release which gets a bit hand-wavey around the details, a properly marked-up document which allows the interested reader to click their way through to more detailed descriptions of what we're looking at would be nice. It's not even clear to me whether the pretty egg images are whole sky or regions of interest - or even which way is 'up'.

  • rate this

    Comment number 157.

    This whole article is an utter tautology! The BBC science correspondent merely repeats the assertion that the CMB picture proves the big bang theory (with bits of titillating, though irrelevant information), but does not in any way explain how.

  • rate this

    Comment number 156.

    We have enough knowledge to live peacefully, but lack the sensibility for that.

  • rate this

    Comment number 155.


    The big bang theory presumes the universe is expanding! Into what scientists do not know, By proposing this theory they must accept the existence of "another place" that is not the universe.
    It's not expanding into anything, it's just expanding. Think of it like all our measuring rods are shrinking, so things are getting further apart. No other place required.

  • rate this

    Comment number 154.

    26.Mark said: "It's not actually light -- it's microwaves -- the frequency has been lowered as space has stretched."

    It's all electromagnetic radiation. "Light" is just a phrase we use to describe the part of the spectrum that our eyes are able to perceive.

  • rate this

    Comment number 153.


  • rate this

    Comment number 152.

    Captain Lort,

    I don't know whether you're trolling or genuine, but the problem is, you're running foul of "Poe's Law": however idiotic a post from a creationist viewpoint is (so that one would naturally assume it to be a parody), there is always out there a real creationist who would have been capable of posting it.


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