The sky according to Planck

By Phil Plait | July 5, 2010 12:00 pm

The European Space Agency just released the first all-sky survey taken by their Planck orbiting observatory, and it’s a beauty!

planck_allsky

[Click to entelescopinate.]

Planck observes the sky from the far infrared all the way out to near radio frequencies, detecting cold gas and dust, star forming regions, and even the subtle and cooling glow of the background fire from the Big Bang itself. In this image, infrared is blue, and the longer wavelengths (out toward the radio part of the spectrum) are progressively more red. It shows the whole sky, which is why the image is an oval; that keeps the map from getting too distorted (like how maps of the Earth are distorted near the edges).

The line running horizontally across the image is the Milky Way galaxy itself. The galaxy is a flat disk, and we’re inside it, so it looks like a line. Think of it this way: imagine you are inside a vast fog-filled room, five hundred meters on a side, but only five meters high. When you look across the room you see lots of fog, but when you look up you only see a little bit — the amount of fog depends on how far into the room you look. The Milky Way is the same way; we’re halfway to the edge of a huge, flat disk filled with dust. When we look into the disk we see it edge-on, and we can see all that dust. Look up or down (toward the top and bottom of the image) and we don’t see as much.

planck_milkywayThis map is in galactic coordinates, meaning the center of the Milky Way is the center of the map. That makes it a little confusing for people used to using coordinates based on the Earth (celestial latitude and longitude), but much easier for astronomers mapping the galaxy and the objects beyond it. That’s what this map was made for, and that’s why it uses a galactic reference.

The wispy material in the image is dust blown up out of the disk by the fierce combined winds of thousands of young massive stars when they are born, and also when they die and explode (a close up from an earlier Planck image can be seen on the left). The reddish glow you can see near the poles of the picture is from the Cosmic Microwave Background, the fading glow of the Big Bang. You can find out more about that in a post I wrote about it a little while back. To many astronomers, that glow is the most important thing in this image, but to get at it they’ll have to digitally remove all the foreground glow of the Milky Way; it’s like looking out a bedroom window at night at a faint object when your light is on. You have too much local glow swamping your view. Removing that foreground light from the Milky Way is extremely difficult and will take astronomers long time, possibly years. But when they do, they’ll have the best ever view of it, and will learn a huge amount about how the Universe itself formed.

planck_allsky_annotatedThe ESA put up a helpful map indicating where some more familiar objects are. For example, Orion is almost all the way to the right, and the big puffy pink circle halfway to the left is the star-forming region in Cygnus, the Swan.

If you want to explore this image more, I suggest heading over to Chromoscope, an interactive map that lets you switch between different wavelengths of light, from radio up to gamma rays. It’s a nifty tool to show you how the sky changes when you observe it in different light.

The Planck data is truly amazing, and I’m very glad to see it released. I know a lot of astronomers who will be hunkering down and spending the next several years of their lives poring over it. They’ll tease out subtle hints about the Universe: how it formed, how it has evolved, and how, eventually, it may die. This is what we are now able to do, we big-brained apes. I have to disagree with Alexander Pope: the proper study of mankind is the Universe, and everything in it.

Credits: ESA/ LFI & HFI Consortia


Related posts:

The Milky Way erupts with cold dust
Herschel and Planck slide across the sky
Herschel and Planck on their way!


CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures
MORE ABOUT: Big Bang, Milky Way, Planck

Comments (38)

  1. PJE

    I would have thought there would be a galactic bulge in the middle. Doesn’t our galaxy have one?

    Pete

  2. Messier Tidy Upper

    Excellent. My congratulations and thanks to the Planck team. :-)

    It shows the whole sky, which is why the image is an oval; that keeps the map from getting too distorted (like how maps of the Earth are distorted near the edges).

    Even *with* an oval projection there is still some distortion isn’t there?
    Although I’m pretty sure it won’t be as bad as using a Mercator (high latitudes end up much larger than equatorial ones) or Phillips (?right name for the weird looking equal area projection that shows nations in their true relative size?)

    Wonder if they could produce a globe or project this image into a planetarium dome? Anybody thought of / done that yet do we know?

    @1. PJE Says:

    I would have thought there would be a galactic bulge in the middle. Doesn’t our galaxy have one? – Pete

    Yes our galaxy has a bulge which is similar to its halo in being generally made of older, dimmer, relatively metal poorer stars. I could be wrong but I think the bulge is similar to an elliptical galxy or globular cluster in having lots of stars but no or very little gas and dust and nebulae which may have some bearing on why the Milky Way’s bulge doesnt show too well here.

    ***

    Some Glactic components :

    (Compiled from pages 155-156, Croswell,ken, ‘Alchemy of the Heavens’, Oxford Uni Press, 1995.)

    Our Milky Way is made up of several distinct regions with particular types of stars defining each region providing another way of classifying stars based on where they’re found or – or more specifically what orbits they have :

    1) Thin Disk – The bright disk or / and arms region of our galaxy to which our Sun and most of the stars visible in our skies belong. These are mostly young stars with many blue-hot celestial luminaries outlining the spiral arms of our Milky Way along with dust clouds and star forming nebulae. It consists of two sub-components :

    a)The Young Thin Disk which is composed of the brightest and youngest stars that are younger than a billion years. Although only 10% of the thin Disk, this incorporates most (if not all) O & B type stars plus supergiants and many A-type stars like Sirius, Altair & Vega.

    b)The Old Thin Disk – includes our Sun, Alpha Centauri and most of its neighbours. These stars range from around 1 billion to 10 billion years old and have been more widely scattered by encounters with gas and dust clouds in the Milky Way. These fall within about 1000 light years below & above the Galactic Plane.

    2) Thick Disk – Older and with more ‘eccentric’ orbits these stars bounce around the region between the spiral arms and the Galactic Halo. They are intermediate in characteristics – like the bulge stars – less metal rich and older than the thin disk stars, more metal-rich and younger than the Halo stars. Some may even have been captured or cannibalised from smaller galaxies that have been merged with our own. Example – Arcturus.

    3) Galactic Bulge – A region surrounding the core of our Galaxy (27,000 ly away) which is crammed full of old Stars found densely-packed together. Although old stars these are also more relatively metal-rich stars with more frequent supernovae and the Galaxy’s gravity leading to higher metal levels.

    4) Galactic Halo A giant sphere of faint stars surrounding our Milky Way and other galaxies. These very old, very metal-poor stars have very long tilted orbits travelling far above and below the plane of our Galaxy. Globular Clusters such as 47 Tucanae and Omega Centauri also orbit in this region. More local examples passing through include Kapteyn’s Star and possibly also Barnard’s Star.

  3. How long did it take to put this together?

  4. Jaki
  5. Messier Tidy Upper

    BTW. For those who don’t already know it may be of interest here to note that :

    Our Milky Way is a barred spiral galaxy (SBc Hubble type) containing about 200 billion stars and some 100,000 light years wide. Our Sun lies in the Orion spur of the Sagittarius arm about 2/3rds the way out.

    (Although this may be slightly out of date on exact numbers etc ..My apologies if so. )

    ***

    “Cosmology also tells us that there are perhaps 100 billion galaxies in the universe and that each contains roughly 100 billion stars. By a curious co-incidence, 100 billion is also the approximate number of cells in a human brain.”
    – Page 237, ‘StarGazer’, Dr Fred Watson, Allen & Unwin, 2004.

    “Put three grains of sand inside a vast cathedral and the cathedral will be more closely packed with sand than space is with stars.”
    – Sir James Jeans, English astronomer quoted on page 28, ‘Skywatching’, David H. Levy, Ken Fin Books,1995.

    “Suppose the nearest civilisation on a planet of another star is, say, 200 light years away. Then some 150 years from now they’ll begin to receive our feeble post-world war II television and radio emission.”
    Carl Sagan, ‘Pale Blue Dot’ page 388, Headline Book Publishing, 1995.

  6. Adrian Lopez

    “The ESA put up a helpful map indicating where some more familiar objects are. ”

    Link?

  7. IVAN3MAN_AT_LARGE

    @ Non-Believer (#3),

    The image shown above is constructed from data taken from the first ten months of Planck’s main mission, with observations beginning in August 2009 (1 st Sky Survey Progress: 14/Aug/2009 – 14/Feb/2010).*

    *Source: PLANCK.

  8. Jamey

    I’d love to see this data made into a layer for ChromoScope!

  9. Literally AWESOME!

  10. IVAN3MAN_AT_LARGE

    @Adrian Lopez (#6),

    Like, er… here’s the link to the annotated map, dude. :cool:

  11. magetoo

    “Link?”

    Seems like the smaller image next to that paragraph is supposed to be clickable too, but evil web gnomes must have messed up the HTML.

  12. Jon Hanford

    “How long did it take to put this together?”

    13.7 billion years, give or take. :D

  13. IVAN3MAN_AT_LARGE

    ERRATUM: Here’s the correct link to the annotated map!

    (Anyway, Phil has fixed it!)

  14. Something really neat would be to show these maps projected onto a sphere – that you could actually spin. Totally practical in this modern computer age. Flash, Java, QuickTime – all can handle that (or as a projection on the inside of a sphere – which would be basically a navigable spherical panorama).

  15. Lucas

    Phil: Why no blog post on NASA’s new focus? “In a far-reaching restatement of goals for the nation’s space agency, NASA administrator Charles Bolden says President Obama has ordered him to pursue three new objectives: to “re-inspire children” to study science and math, to “expand our international relationships,” and to “reach out to the Muslim world.”

    youtube link to interview: http://www.youtube.com/watch?v=e857ZcuIfnI

    Looks like the space program is dead. :(

  16. Damon

    This is staggering. Lots to look at and think about here. Thanks for posting.

  17. paletas
  18. LeslieS

    I clicked on the link to your older post about the remnants of the Big Bang. I’m curious about the statement that the universe is flat. I clicked the link in that post as well that took me to NASA’s website and a very brief explanation, but I’m still trying to wrap my head around the idea. Can someone here please take pity on me and explain that in more detail?

  19. Brian137

    Messier Tidy Upper:

    Even *with* an oval projection there is still some distortion isn’t there?

    Yes. Some “curved” surfaces, as for instance cylinders, can be cut and then unrolled to lie flat with no distortion. This flattening can be achieved because the cylinder forms a straight line along a dimension parallel to its axis. A sphere is curved in a more fundamental way because it is curved in every direction. As a result, a sphere can never be flattened without distortion. We basically view the CMB from the center of a sphere.

  20. Brian137

    LeslieS:

    I clicked on the link to your older post about the remnants of the Big Bang. I’m curious about the statement that the universe is flat. I clicked the link in that post as well that took me to NASA’s website and a very brief explanation, but I’m still trying to wrap my head around the idea. Can someone here please take pity on me and explain that in more detail?

    In school, we studied Euclidean Geometry. For most of the year, we studied figures lying in the 2-dimensional Euclidean plane, but towards the end, we talked about prisms, cones, and other shapes in 3-dimensions. When we say that the universe is flat, we mean that it is spatially very nearly a 3-dimensional Euclidean space.

    We have all heard that Einstein showed us that space is curved, which he did do. Our current view is that, although the universe is sometimes curved locally, the overall shape is pretty flat. According to this way of looking at things, those local curvatures are like shallow dimples in a vast flat sheet, so that is why I have used terms like “very nearly” and “pretty.”

    Don’t let my flat sheet analogy distract from the fact that we are talking about a 3-dimensional space. Another caveat, is that we can only really know about the so-called “observable universe.” About whatever lies beyond our ability to see we can only make educated guesses.

  21. LeslieS

    Thank you so much, Brian137! That was very helpful.

  22. Messier Tidy Upper

    @19. Brian137 Says:

    Messier Tidy Upper: “Even *with* an oval projection there is still some distortion isn’t there?”

    Yes. Some “curved” surfaces, as for instance cylinders, can be cut and then unrolled to lie flat with no distortion. This flattening can be achieved because the cylinder forms a straight line along a dimension parallel to its axis. A sphere is curved in a more fundamental way because it is curved in every direction. As a result, a sphere can never be flattened without distortion. We basically view the CMB from the center of a sphere.

    Thanks for that explanation. Make sense. :-)

    Anyone know if the Planck people are working on a globe or planetarium projection of this or if any other similar map (eg. WMAP, KOBE, WISE etc ..) has done so? :-)

  23. Messier Tidy Upper

    On our Milky Way galaxy see also :

    http://en.wikipedia.org/wiki/Milky_Way

    Not much there on the galactic bulge though.

    The galactic disc, which bulges outward at the galactic center, has a diameter of between 70,000 and 100,000 light-years. The distance from the Sun to the galactic center is now estimated at 26,000 ± 1,400 light-years, while older estimates could put the Sun as far as 35,000 light-years from the central bulge.

    It’s not very clear or very much though unfortunately- and there seems some confusion as to names with Galactic “centre” “core” and bulge” w all of which may or may not be used interchangeably methinks? :-(

    I’d certainly recommend reading Ken Croswell’s ‘Alchemy of the Heavens’ (Oxford Uni Press, 1995.) book as an excellent source of info and a good read on this topic. Don’t let the somewhat New Age-y sounding poetic title put you off – it is actually a very good and well written popular science text. I’d also highly recommend Croswell’s website :

    http://www.kencroswell.com/author.html

    Which contains lots of his articles and excepts of his books etc .. & is a great site. (IMHON.)

    There’s a bit more here :

    http://en.wikipedia.org/wiki/Galactic_bulge

    But not on the Milky Way’s own bulge specifically.

    I suppose I could’ve answered (#1.) PJE’s question with a simple “yes!” but I hope this has been interesting / informative for folks. ;-)

    ***
    PS. Sorry if I get a bit carried away & provide too much info. on occassion here. I know I can be a bit wordy. :-(

  24. John Paradox

    The second photo, that links to ‘the Milky Way erupts with cold dust’ reminds me of the Star Wars/Star Trek ‘explosion waves’ (e.g. the Death Star being destroyed, the Klingon moon exploding).
    Too much TV/DVD….

    J/P=?

  25. JB of Brisbane

    Is this a Mollwiede projection, or is it just coincidentally the same shape?

  26. Nigel Depledge

    Wow!

    Amazing image, and I hope it proves as fruitful scientifically as it is beautiful to look at.

    One little quibble:
    The BA said:

    The Planck data is truly amazing, . . .

    Should be “The Planck data are truly amazing” or “The Planck dataset is truly amazing” or some other permutation thereof.

    I know, I know, casual useage and all that. But “data” is still the plural of “datum”.

  27. Lukester

    I sure hope this makes Muslims feel better about their contribution to math and science!

  28. MartinM

    This seems like rather an odd choice of post for crazy bigots to comment on.

  29. Kinky

    @ 28. Nigel Depledge

    I know, I know, casual useage and all that. But “data” is still the plural of “datum”.

    Datum? Date-um? I thought that was slang for going out with two girls (or whatever takes your fancy) at once? ;-)

    @ 31. MartinM Says:

    This seems like rather an odd choice of post for crazy bigots to comment on.

    That’s why they’re called crazy bigots not sane ones I guess. ;-)

  30. Andrew

    All projections of a sphere on to a plane are distortive to some degree. Astronomers tend to use the Hammer-Aitoff projection for whole-sky images, rather than Mollweide. Both are 2:1 ellipses and equal-area, and both distort angles and shapes (but in slightly different ways). The most noticeable difference is that lines of latitude end up curved in Hammer-Aitoff but straight in Mollweide. See http://en.wikipedia.org/wiki/Hammer_projection and http://www.radicalcartography.net/?projectionref

  31. Michael T.

    Chromoscope is too cool but why are there what looks like scratches in the x-ray part of the spectrum?

  32. Brian137

    An easy way to see that a sphere cannot be projected onto a flat surface without distortion is to imagine cutting a basketball into two hemispheres. The problem of making a distortion-free flat projection of the hemisphere is equivalent to the problem of pressing one of the basketball halves flat against the floor. You cannot do the latter even with the aid of cuts, so you cannot do the former.

  33. Joel

    Amused to note that the file name for the Planck image is:
    PLANCK_FSM_03_Black_frame_orig.jpg
    “FSM”??? Should we take this as evidence that this is actually an image of…?

  34. Hand this over to the Google Earth folks so we can see it projected inside a sphere!

  35. Andrew

    This may be slightly off topic but..
    In http://www.sciencedaily.com/releases/2006/09/060905104549.htm, it refers to an article: “A comparison between the x-ray predicted and WMAP observed Cosmic Microwave Background temperature decrement”,
    which seems to indicate that there is more than one source of CMBR (apart from the big bang), and it is impossible to distinguish what radiation came from what source. Can someone point me toward a good explanation for this anomaly?

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