The Milky Way erupts with cold dust

By Phil Plait | March 25, 2010 8:00 am

One of my favorite things about astronomy is that it opens our eyes to things those eyes literally cannot see.

I have been to dark sites countless times and gazed up at the Milky Way; that dim and fuzzy path of light that represents the combined glow of billions of stars, gas clouds, and dust. To my eyes, it’s bright enough to see some details, and it’s lovely… but what we see is a facade, the barest skin draped thinly over depth and grandeur we can hardly perceive.

That is, until we look at our galaxy with new eyes: ones tuned to the far, far infrared. Then we see magnificence on a scale so breathtaking we can hardly comprehend it. Behold!

planck_milkyway

That is what lurks beneath the dim view our eyes collect! It’s what the European Space Agency’s Planck observatory sees when it looks at the Milky Way.

Wow! This image is a whopping 55 square degrees of sky — 280 times the area of the full Moon on the sky — centered near the constellation of Aquila the Eagle. The resolution of the data is about 5 arcminutes, meaning objects as small as 1/6th the size of the Moon on the sky can be distinguished; that’s very high-res for images in this region of the electromagnetic spectrum. And as an astronomer who is pretty familiar with the night sky, I have to say it’s very weird to see an image like this and have almost no idea what’s in it.

I mean, I know a lot of what I’m seeing in general, but specific objects are totally impossible to identify. That’s because this image is hugely removed from visible light. It’s a three-color image composed of separate shots in the wavelengths (think of them as colors) of 100, 350, and 540 microns. For comparison, the longest wavelength of light our eyes can see is about 0.7 microns or so; these Planck images are therefore way the heck and gone in the infrared.

What we’re seeing is very cold dust, and by very cold I mean very cold: much of it is a frigid 12 Celsius above absolute zero. In Fahrenheit, that’s -438°. Yes, four hundred thirty eight degrees below zero.

This represents dust far away from the warming light of stars, dust that is sitting in deep space, radiating away feebly in the far infrared. Mapping this dust tells us much about it, like how stars make dust and fling it into space, and how the dust behaves when it’s out there.

See that bright line right down the middle? That’s the dust located in the disk of the Milky Way galaxy itself. Our galaxy is a flat disk 100,000 light years across, but maybe only 1% of that in thickness. We’re located inside that disk, so that when we look in that direction we see it projected as a line across the sky. That’s where most of the gas and stars in the galaxy are located, so that’s where most of the dust is as well.

But I’m fascinated by the structure of the dust above the galactic plane. There are swoops and swirls, filaments and ribbons. I’m drawn to the long thin line on the right that must be dozens or hundreds of light years long; it appears to end in a swirl of dust. What the heck could be causing that? I’m not sure. There’s so much going on here that it’ll be some time before astronomers can sort it all out.

planck_milkyway_350micronsOne thing I want to point out is the one component of that image taken at 350 microns, seen here on the left. This is extremely cold dust, and as a major geek I can’t help wonder if the structure seen here was diverted by Malcolm McDowell to swing past Veridian III.

And if you’re looking for irony, you’ve found it: Planck is designed to investigate the Cosmic Microwave Background, the faint glow leftover from the Big Bang. As far as Planck is concerned, the Milky Way is a foreground object blocking the view! It has to map our local space very carefully so that emission can be removed from the actual target data, and reveal what the far more distant background Universe can tell us.

It’s true in astronomy as well as so many other aspects of life: what’s signal to one is noise to another.

Credit: ESA and the HFI Consortium

CATEGORIZED UNDER: Astronomy, Pretty pictures

Comments (44)

Links to this Post

  1. Γαλαξίας on the rocks « On the way to Ithaca | March 26, 2010
  2. » Infrared Eye Candy | March 28, 2010
  3. March 27 | JosephTBradley.com | March 30, 2010
  1. Ismael

    Stunning! The undiscovered country

  2. Michelle R

    Wow. At first I thought someone had set fire to some oil. It really looks like fancy flames.

  3. John

    Amazing to see warping in the disk.

  4. Peter F

    I thought it looked more like the “galactic barrier” from Star Trek: The Original Series:

    http://memory-beta.wikia.com/wiki/File:Galactic_Barrier.jpg

  5. Off topic but relevant in some sense:

    Would anyone be kind enough to point me in the direction of some animations on the web relating to how we work out and know the distances to objects like stars, galaxies, GRB’s etc please?

    Thanks in advance.

    Ganzy

  6. TheMark

    Very nice!

    Off topic:
    http://news.yahoo.com/s/space/20100324/sc_space/lastchancetogetagoodlookatmarsuntil2012
    has a link near the bottom labelled: “Video Show: Bad Astronomy with Phil Plait”
    which leads to:
    http://www.space.com/common/media/show/player.php?show_id=32
    Is this new material? They didn’t opt for any kind of date/time on those pages…

  7. Messier Tidy Upper

    Awesome image & write-up! ;-)

    Being uber-pedantic & picky here (sorry) but shouldn’t this:

    have been to dark sites countless times and gazed up at the Milky Way; that dim and fuzzy path of light that represents the combined glow of billions of stars, gas clouds, and dust.

    Really be :

    “.. gazed up *into* the Milky Way?”

    Because we can’t see our Galaxy from the outside or in total just a small section of it?

    We can gaze up at say the Large Magellanic Cloud or Andromeda in view the entire galaxy at once and in full but we only ever see a small part of our own Galaxy from our very limited perspective within it – right?

    To gaze up at the Milky Way wouldn’t you need to be in a different galaxy?

    As noted though, being uber-pedantic there. Otherwise, great post & much appreciated. :-)

    Oh as for this :

    I’m fascinated by the structure of the dust above the galactic plane. There are swoops and swirls, filaments and ribbons. I’m drawn to the long thin line on the right that must be dozens or hundreds of light years long; it appears to end in a swirl of dust. What the heck could be causing that? I’m not sure.

    Well I’m not sure either but an idea or three :

    1) Gravitational waves from past interration with other galaxies such as the Magellanic clouds?

    2) Ripples in the density waves that form our galaxies spiral arm or some connection with the bar in our barred spiral Milky Way?

    3) Some connection to do with the passage of a globular cluster through the spiral arms maybe?

    No idea if these are correct or even plausible or anything – just brainstorming with my fingertips.

  8. Russell

    Thanks Phil !

    You made me get all misty eyed at work! The beauty of that thing is awsome
    to “behold” indeed.

    When you speak of “dust” in space, is this like dust under my couch minus the coins and gum wrappers, or are we talking about gas particles, or what ???

  9. Greg in Austin

    It looks like fire.

    They say time is the fire in which we burn.

    8)

  10. PlanckEpoch

    Phil,
    Recently, the hubble ultra-deep field camera imaged the most distant galaxies ever seen. This group of very blue galaxies is thought to be around 13 billion years old, about 1.5 billion years older than predictions given by the Standard Model.

    The light from those galaxies has been traveling for 13 billion years. Is it a legitimate question to ask, “where are they now?” Does the current conception of space time allow for the concept of an absolute “now?” In other words, those blue early galaxies have been doing something for the last 13 billion years; moving away, colliding, evolving different elements through stellar evolution, etc.

    Has anyone constructed a 3-D model of what the universe looks like “now?” Perhaps based on projections of movement and known vectors and masses of the observed galaxies and clusters, and progressively time-smoothed over distance to capture of snapshot of the absolute “now” condition of the visible universe?

    This always confuses me when images are shown of the big-scale universe. If those early galaxies are measured to be n-number of light years away, that’s how far they were 13 billion years ago. By now, they must be enormously farther away than that – aren’t all our 3-d images of the known universe vastly under-scaled?

  11. John Paradox

    The first photo, for some reason, reminds me of FarScape…

    J/P=?

  12. Chris Winter

    “To my eyes, it’s bright enough to see some details, and it’s lovely… but what we see is a facade, the barest skin draped thinly over depth and grandeur we can hardly perceive.”

    “To know ultraviolet, infra-red, and x-ray:
    Beauty to find in so many ways.
    Two notes of the chord, that’s our full scope.
    But to reach the chord is our life’s hope.”

    – The Moody Blues, In Search of the Lost Chord

  13. IVAN3MAN AT LARGE

    Ganzy (#4):

    Would anyone be kind enough to point me in the direction of some animations on the web relating to how we work out and know the distances to objects like stars, galaxies, GRB’s etc please?

    No animations but Wikipedia has a good article on the various methods used by astronomers to determine the distances to celestial objects: Cosmic distance ladder.

  14. photosphere

    I tawt i taw a tiamat!

    wow just wow

  15. Gary Ansorge

    Does that dust/gas include a cold plasma? If so, that might go a ways to explaining the “swirl of dust” as an interaction with a local magnetic field.

    That first pic would make a great screen saver. It reminds me a bit of an early StarTrek show, where they’re heading toward the galactic rim.

    GAry 7

  16. SteveG

    Looking at this image, I get the distinct impression that our galaxy is “steaming”, which I guess in a way it is, but instead of wisps of water vapor we have wisp of very cold dust.

    Great stuff.

  17. It never ceases to amaze me how switching cosmic scales reveals ever more mind-blowing dynamics. Looking at a nebula being roiled by new stars is incredible. Zooming out to the flow of dust around the entire frakkin’ galaxy?! Incredible^2.

  18. ggremlin

    Where is Mega-Maid when you need her?

  19. jcm

    Fiery! Yet so cold!

  20. BGC

    Phil,
    Didn’t you once point us to a model of star formation that used novae to push dust around until you got masses thick enough to produce stars? Is your dust feature above the galactic plane an outgrowth of the same sort of process? Multitudes of supernovae explosions each of which produce some amount of dust that is blown off into space? Each new wave of dust just piles up below the last one? Alternatively, or maybe in addition, is there a sort-of cumulative solar wind effect pushing the dust outward? I’d think that the dominant direction would be away from the main mass of stars, i.e. the galactic plane. Sorry, I keep seeing it in a fluid dynamics sort of way (which may be wrong I admit, but I’m a geologist not and astronomer).
    BGC

  21. Melanie (Australia)

    Leaves me breathless!

  22. Yeebok

    Thanks for this description Phil – seen this pic a few times and it’s never been explained in a way that visualised it for me as well as that did. Fascinating stuff.

  23. Allen

    Posted this link on IRC, got this in reply:

    [18:01] It’s cool, but it’s no candy bar.

    Very stunning picture. It’s nice to see things that we’re familiar with in different spectra of light.

  24. Beautiful!! But you’re right about one’s person noise…. As pretty as this is, I can’t wait for them to get it out of the way and get us some cosmology ;)

  25. Awesome picture, and good post – but when are you, as a scientist and vocal supporter of all things science, going to stop using outdated units of measurements. I always find it amusing to see American scientists still clinging on to Farenheit, ounces and feet…

  26. Wesley Struebing

    Magnificent, Phil! The pics you pick never ease to delight and amaze!

  27. Crudely Wrott

    @12: Nice Moody Blues reference.

    Just in case no one has noticed, there is a very clear face in this picture. Look closely at the center of the bright, lilac swirl on the far right, just above center. It’s really quite detailed, including the bolt of lightning issuing from the mouth.

    Now let’s start “watching and waiting” for the tabloid press to latch on to this.

  28. My God. Vernor Vinge was right!

  29. Jason Dick

    I should mention that within the Planck collaboration, there is a rather large and active team specifically dedicated to galactic science (as opposed to just seeing it as a foreground). Anyway, if you want an idea of what you’re looking at here, perhaps this will help:
    http://www.chromoscope.net/

    It’s pretty easy to pick out where this image is looking at on the sky by comparing the Far-IR image there.

  30. Jim Galasyn

    All that dust is being heated from below by the galactic disk, so I wouldn’t be surprised if there are vortex structures that emerge to transport that energy “upward.” Very, very slowly.

  31. Horus Kol (#25): Whether you find it amusing or not, most of the American public doesn’t know Celsius, and few in any country know Kelvin. My job is to communicate, so I use units my audience is familiar with.

  32. MadScientist

    Oooooo! I thought it would be interesting to see what Planck would find since it can see much colder particles than any other astronomical instrument put into space and may be able to observe things which may not even be observable via transmission of visible/uv/near-IR starlight. This is awesome. I didn’t even realize Planck was meant to observe the cosmic background – hahaha – funny how an earthbound spectroscopist can be right about what Planck can see while being ignorant of the purpose for which the instrument was built.

  33. Gary Ansorge

    20. BGC

    ” I keep seeing it in a fluid dynamics sort of way ”

    Nothing wrong with that. The equations of fluid dynamics will apply in a general manner to about anything that flows. The major difference between what we’re seeing here and “normal” fluids is that this dusty material is also subject to galactic magnetic fields, which means we have to use additional field equations to describe their interactions.

    Gary 7

  34. OtherRob

    @Peter F, #4:

    That was my immediate thought as well. :)

  35. Damon

    This is breathtaking, to the eye and the mind. Thanks Phil.

  36. John Sandlin

    Phil,

    You could always use the standard notation on plain text and put in parenthesis (that’s xx degrees F for folks in backward countries). Well, maybe something a little more polite, but still… a thought.

    You’re obviously getting the articles with the official units and having to convert anyway.

    JBS

  37. BGC

    @37.
    Thanks Gary. That’s a helpful extra bit of info. Are there magnetic lines associated with the larger, whole galaxy (a scaled up version of the magnetism of a star)? Or is it more of a cumulative effect from the magnetism of many, many stars? Are the magnetic lines at this scale understood or just theorized?

  38. Gary Ansorge

    38. BGC

    Take 100 billion stars and their assorted magnetic fields, throw in plasma flow throughout the galaxy, with its attendant field properties, mix throughly and voila,,,total confusion. We can really only describe these interactions statistically. We still don’t completely understand the interactions of our own suns magnetic field lines ( but we’re learning).

    Actually, the guy you should be asking would be a specialist in cosmology. My background is in applied physics, rather than theoretical physics(ie, I are an engineer, I makes thingys work).
    I have a basic understanding of nuclear/particle physics, which is a far cry from dealing with these mega galactic processes. Perhaps Neil Degrass Tyson would be the guy to ask.

    Cumulative effects seem to be the way these processes work but for more accuracy, ask an expert.
    (Paging Dr. Tyson,,,hello?)

    Gary 7

  39. Chris A.

    It makes me think of what we might see if we could see M82 up close, in IR (Spitzer gave us the big picture view, which still blows my mind for the sheer scale of it):

    http://www.spitzer.caltech.edu/Media/releases/ssc2006-09/release.shtml

    That’s an impressive dust plume!

  40. Many thanks! IVAN3MAN AT LARGE

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »