Planck telescope: A map of all the 'stuff' in the cosmos

Map of distribution of matter across the visible universe

Europe's Planck telescope, which last week showed us a picture of the oldest light streaming across the Universe, has another trick up its sleeve.

It has also mapped the distribution of all the matter in the cosmos.

This was done by analysing the subtle distortions in the ancient light introduced as it passed by the matter.

The effect is a direct consequence of Einstein's theory of general relativity which tells us that space is warped by the presence of mass.

Prof Simon White likens it to the way light is bent as it passes through the lumpiness of an old glass window pane.

"If you know what you're looking at outside, you can use the distortions to say something about the glass," the Planck researcher said.

"There have been 'gravitational lensing' detections before over small areas, but this is the first time we've been able to do this kind of thing over the whole sky," he told BBC News.

The new map is a smart byproduct of the European Space Agency (Esa) telescope's main mission which is to survey the Cosmic Microwave Background, or CMB - a pervasive but faint glow of long-wavelength radiation that comes to us from the very edge of the observable Universe.

Planck artist impression The Planck satellite was launched in 2009 to map the Cosmic Microwave Background

That light essentially carries a record of all the intervening structure it has encountered on its journey.

What you see in the map on this page, split across the two hemispheres of the sky, is the sum of all the matter/mass along the line of sight.

Red denotes those regions where there is more matter/mass than average; and blue denotes regions where there is less than average.

The white edging in the North/South projections is the plane of our Milky Way Galaxy.

This great mass of stars makes it impossible to discern the delicate gravitationally lensed distortions and the region is simply masked out.

The map is a very complex thing to produce, and reflects not only the extraordinary sensitivity and resolution of Planck but also the immense sophistication now possible in the statistical analysis of the telescope's data.

Scientists have checked the map against the distribution of matter obtained by other means.

In the near Universe, for example, it should fit with the detailed information we now have on the way clusters of galaxies are dotted across the sky. And it does.

For the more distant parts of the Universe, Planck itself can do the test. It can use its High Frequency Instrument to look for the infrared emission from dust that is warmed by stars associated with far-off galaxies.

The pattern in this light acts as a kind of proxy for the history of star formation, and therefore a history of structure in the cosmos. Again, it agrees well with what the new Planck map is telling us about the distribution of matter/mass.

Big galaxy clusters Planck has now catalogued more than 1,000 big galaxy clusters - many new to science

Of course, it is thanks to Planck that we now know there is slightly more "stuff" out there than we thought, even if most of it is in a form beyond direct observation.

The analysis of the CMB data, released last Thursday, indicates that only 15.5% of the Universe's matter is what we would call "normal" - that is, the atomic material from which planets, stars and galaxies are built.

Planck's cosmic numbers

  • The telescope has produced a new contents list for the Universe:
  • 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
  • Planck has also measured the expansion rate of the Universe
  • This is described by a value that scientists refer to as the Hubble Constant
  • It is found to be 67.2 km per second, per megaparsec (or per 3.2 million light-years)
  • This suggests the Universe came into existence about 13.8 billion years old

The rest (84.5%) is "dark matter" whose precise nature currently eludes scientific description.

The map at the top of this page makes no distinction. It is an integration of both normal and dark matter.

Planck can, however, be used to find a lot of previously unobserved regions of normal matter. These are large galaxy clusters.

They are identified using another clever trick named after the two Soviet physicists who proposed it in the 1960s.

Rashid Sunyaev and Yakov Zel'dovich said that a small fraction of the CMB light particles, or photons, should get a little kick in energy when they pass through the hot gas found in big clusters.

Once more, the effect is subtle but very characteristic, and Planck has used this Sunyaev-Zel'dovich method to catalogue more than 1,000 big cluster candidates, many of which had not previously been on the books.

"Planck is a discovery machine," the Esa project scientist Dr Jan Tauber told BBC News. "The data is now out there and people will really start to dig into it. There are a lot of scientists inside the Planck Collaboration but there are many more that are outside. They are going to find some great new uses for the data."

CMB - The 'oldest light' in the Universe

Planck 2013 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

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Jonathan Amos Article written by Jonathan Amos Jonathan Amos Science correspondent

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  • rate this

    Comment number 19.

    These images look like marble blocks to me, i.e. reveal who or what you want depending how you chip away at them.
    I still don't see how measuring the expansion of visible matter into the space around it can be intrerperted as matter and the space around it both expanding at the same time!

  • rate this

    Comment number 18.

    Jonathan Amos needs to proof-read his articles...
    In the main text it states...

    only 15.5% of the Universe's matter is what we would call "normal"
    The rest (84.5%) is "dark matter"

    and in the box on the right hand side it states...
    Planck's cosmic numbers
    The telescope has produced a new contents list for the Universe:
    4.9% normal matter
    26.8% dark matter
    68.3% dark energy

  • rate this

    Comment number 17.

    Damien George, from Cambridge University, has put together an excellent visualisation of the CMB: . It's a 3D globe (Google Earth style), that also lets you select different wavelength bands.

  • rate this

    Comment number 16.

    I'm just waiting for the good old religious comments that will be rapidly voted down. I am pretty sure most of these people are trolls but hey, still funny. On the subject however, AWESOME. I wish that more money was pumped into science/space exploration. THAT drives the economy as it allows man to dream, to push himself to the next level.

  • rate this

    Comment number 15.

    @ U14576049
    Nothing spectacular but not straight forward to make. It was a copper laminated component that supported and conducted heat away from the third and final stage of a 3 stage cooling system designed to keep the craft at almost absolute zero. The component was vacuum brazed in a small furnace that I was operating in my garage while searching for a small industrial unit.

  • rate this

    Comment number 14.

    The technological advancements of the Planck and the capabilities allowed through it are staggering.

    As humans, curiosity is one of our greatest traits. Understanding the universe and its origins is something that we should all strive for. We are a pixel, or a paint stroke on the big picture of existence but that shouldn’t stop us from seeing the greatness in all its glory.

  • rate this

    Comment number 13.

    If 15.5% is normal matter and 84.5% is dark matter, then what happened to all the dark energy? It has gone from 68.3% to zero. Surely there is a reporting error in here somewhere.

  • rate this

    Comment number 12.

    10 Mysturji - The first one is referring to percentage of all matter that is normal matter, the second one is referring to the percentage of everything, including energy, that is normal matter.

    I wonder if dark matter has its own discreet particles like normal matter, or if it's just an amorphous cloud. Would be interesting if there were "dark atoms" made up of dark electrons, protons & neutrons.

  • rate this

    Comment number 11.

    I'll second the applause for the article. Compare this to the Sukman one on extinction and the woefull RCJ reports.
    jobsworthwatch, you HAVE to tell us which bit you made!

  • rate this

    Comment number 10.

    Auntie Beeb... there is a discrepancy in this article:
    "only 15.5% of the Universe's matter is what we would call "normal" "

    "Planck's cosmic numbers
    The telescope has produced a new contents list for the Universe:
    4.9% normal matter - atoms, the stuff from which we are all made"
    Please clarify/correct.

  • rate this

    Comment number 9.

    Great article, at least you didn't open this one for comments so I don't have to read the drivel from the luddites, mypoics and sky fairy botherers.

    Oh... wait...

  • rate this

    Comment number 8.

    Back in 2003 having been made redundant and then, working self-employed from home, I made a part for this spacecraft in my garage. I checked earlier this week with the customer to see if the part I made had actually been used on the spacecraft. Astonishingly the answer was yes!

  • rate this

    Comment number 7.

    Finally proof that the Universe was sneezed out of the nose of the Great Green Arkleseizure.

  • rate this

    Comment number 6.

    Mind numbingly complex but it stirs the imagination
    Wonderful stuff

    And “stuff” is about the only word suitable to describe the matter that makes up most of the universe

    What is it, this Dark Matter?

    When we find out it will probably change our entire view of the universe and present loads more questions

    As I said, wonderful stuff !!!

  • rate this

    Comment number 5.

    As a cosmology undergraduate I must say this is a fantastic achievement and I can't wait to see where this leads regarding dark matter/energy studies.

    Just a shame that science like this, which can lead to massive financial benefits isn't better funded.

  • rate this

    Comment number 4.

    If, when presented with magnificent new data like this, all you can do is bash religion, then there is something wrong with your own belief system.

    As an atheist, I see science as an evolution of religion. They both stem from a spiritual motivation to understand the cosmos. Space research has been dominated by Western societies built on Christian values of tolerance and collaboration.

  • rate this

    Comment number 3.

    Awesome achievement. Just shows what some of us humans are capable of

  • rate this

    Comment number 2.


    You've done it now! The religious will be here in due course to offer their inane and ill-informed opinions, they always do. This is great science but, sadly, many are incapable or unwilling to recognise that fact.

  • rate this

    Comment number 1.

    Reliion has the age of creation at 5000 years old, why the big discrepancy. Isn't science great :)


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