Another Hubble stunner… and it’s a repeat. Kinda.

By Phil Plait | October 2, 2007 7:02 am

It’s been a while since I posted a beautiful Hubble image, so I’m pleased with this one. And even better, it’s a new view of one of my favorite objects of all time!

What you are seeing is NGC 3603, a young cluster of stars, and the gas and dust from which they formed still surround the stellar nursery. The brightest stars there are 20 – 40 times the mass of the Sun. These massive bruisers have powerful stellar winds, and they also emit a flood of ultraviolet light. Both of these tend to push back the gaseous curtain enshrouding them, letting us peek in on the newborns.

The cluster is pretty dense, as you can see. If you let your eyes scan over the image (and please, grab the higher res versions!) you can see lots of structure that seems to be aligned radially with the center of the cluster. That’s real! The flood of light and wind from the stars sculpt the surrounding nebula into those odd shapes. It’s a surreal painting, the sky as its canvas, created in slow motion over hundreds of millennia.

It’s also 20,000 light years away: 120 quadrillion miles.

The image is using the "new" camera on board Hubble, the Advanced Camera for Surveys, or ACS. Years ago, Hubble took an image of NGC 3603 with the Wide Field/Planetary Camera 2 (WFPC2). Here’s that image:

There are quite a few differences. The ACS has a square detector, where the WFPC2 had four chips, with one having a smaller field of view (hence the step ladder or stealth bomber shape). WFPC2 has lower resolution than ACS, so the stars in the center appear more crowded. Different filters were used, and different colors in the post-processing, so the images show different (but similar) features, with different colors.

In the WFPC2 image, see that weird ring around the bright star, and the two fuzzy spots to the right and left of it? That star is called Sher 25, and in a few thousand years, it’s gonna asplode. This is not a guess; it’s a certainty. It’s a dead ringer for the star that blew up to form supernova 1987A, which I studied for my PhD. 87A’s star also had that ring, and the two caps. They’re actually part of a bipolar nebula, an hourglass shaped figure around the star, formed in the last few millennia of the dying star’s life. I have more info on all that than you’ll need on my Bitesize Astronomy pages (it’s a series of several short essays, so kill some time over there).

In the new image, the nebulosity around Sher 25 is harder to see. Here are zooms of the two images side-by-side:

Although the ACS is more sensitive, the WFPC2 image shows the gas better because it used filters that select the light the gas emits more strongly. When the WFPC2 image came out, I was floored. It was amazing, and it was the first time I saw an object that looked like supernova 1987A! Then, in January 2007, several more such objects were announced, too.

Actually, the ACS image can be useful in studying Sher 25, even though it doesn’t show the gas well. By looking at the light not emitted by the gas, we can get a better understanding of the neighborhood of the objects there. You can see more stars in the ACS image, for example, which allows astronomers to take a better census of the stellar population in the cluster.

I have no doubt that eventually a paper will come out of this. I’ll read it with interest — I spent a long time studying this kind of object — but with more than just scientific curiosity. I’m human, too, and sometimes it’s nice to catch up with old friends.


Comments (29)

  1. BGH

    Awesome!! Phil, I can always count on your blog to keep me up to date with happenings from Hubble.


  2. Beautiful. Very cool.

    Of course your “rational”, “logical”, “educated” mind missed the obvious Angel on the left side of the zoomed, older image. Clearly, Jesus told that Angel to hightail it outta there before the star blows up. Just more proof that God created the universe, evolution is wrong, and Jesus loves you! (Or something.)


  3. Meg

    A spectacular image, Phil. Thanks for sharing. There’s wonderful 3-D swirl to the stars in it that outdoes anything made up for the movies.

    Of course, adding on to Ipecac’s comment, I must add that the red star in the upper left is clearly the home of satan!

  4. Rowsdower

    Amazing what nature produces. I wonder what it would look like from the inside. (I keep thinking about Asimov’s Nightfall. Which also makes me wonder what the radiation would be like inside a dense cluster of stars.)

    If that one star is going to explode in a few thousand years, does that mean that it may have actually gone nova or is in the process of doing so? I mean it’s 20,000 light years away which means we’re seeing how it appeared 20 thousand years ago.

  5. Doc

    Ok, I hope this isn’t a stupid question but … what does this cluster look like to the naked eye?

    Is it just a white dot? Is it visible at all? Is it a faint smear?

    Whenever I see these kind of pics (which I love, by the way) there’s a naggling little voice in the back of my head that keeps saying “Yes, but what does it *really* look like?”

  6. Doc


    This also relates to my question above. If we lived on a planet in a cluster like this, would our night sky be a funky light show, or would it be similar to what we have now?

  7. twinner

    So are you going to make a new BA logo using this new image?

  8. > “Yes, but what does it *really* look like?”

    Depends on the spacetime orientation of the observer. Ain’t relativity grand?

    Anyway, most spiffy indeed. I wonder what a (super?)nova in a clearly dense pack o’ stars would do–probably nothing, I’d imagine, due to inverse square laws, and the fact that I don’t see self-sustaining fusion reactions as particularly being bothered by being bombarded by gamma radiation.

    > Of course your “rational”, “logical”, “educated” mind missed the obvious Angel on the left side of the zoomed, older image.

    That’s not an angel, that’s the Tin Man from TNG. Quite understandable that a spaceborne organism would want to get beyond the safe radius of a star about to go plooie.

  9. aiabx

    AAAHH! Space ghosts!

    I need to get down south to see this thing with my own eyes.

  10. OtherRob

    But what does this have to do with astronomy?

    Oh, wait….

  11. James


    Why do the stars have square crosses going through them though – is this something produced by the camera? Or is it added later through processing the image?

  12. > Why do the stars have square crosses going through them though – is this something produced by the camera? Or is it added later through processing the image?

    Because Jesus is fusion. Fusion is Jesus. The worms are the spice.


    *cough* Sorry, couldn’t resist.

  13. Gnat

    I thought it looked like the Monopoly guy (with the monocle and mustache).

    But seriously, how close are those stars to each other? And what is the likelyhood that each star will have its own planet system? Or could the star cluster be considered a “solar system”?

  14. Brown

    The hourglass shape with the ring … I’m reminded of the d(z-squared) electron orbital.

  15. Irishman

    James, the spikes are digitally added by the research team PR person to make the released images “pretty”. 😉

    Actually, they are called “diffraction spikes”. They are caused by the elements in the scope that hold the detectors in front of the mirror.

  16. Quick Question: Is this taken in visible color, or are these showing a visible color representation of IR? Or for that matter is it artificially colorized

  17. aiabx

    If you looked at this through a typical telescope, you’d see a cluster of stars with some grey wisps of nebulosity around it. As far as I’m concerned, that’s cool – I’d rather see the blandest grey smudges with my own eyeball than all of the hubble pictures ever imaged.
    Close up, the nebulosity would still be a disappointment – mostly grey haze, maybe a few green or red smudges – but the star cluster would be awesome. It’d be like living in a giant disco every single night.

  18. Arthur Maruyama

    For Doc:

    More details on this image can be found here:

    Under the Fast Facts tab the image is “roughly 3 arcminutes” across, which (if I have done my math correctly) is a patch of sky about the apparent size of Mare Nectaris (Sea of Nectar, 333 km in diameter) on the Moon.

    For your convenience, here is a labelled picture of the Moon:

    For drbuzz0:

    This first image BA posted is a composite of three filtered images, so the image is not as a human would be able to see it even if our eyes could see objects of this visible magnitude. Again from the Fast Facts from the above: I am guessing that the name of the filters used gives the peak light (in nanometers) that passes through them, so the filter used for blue is actually in the violet range of the spectrum; that for green, actually yellowish green; and that for red, actually infra-red. These filters are presumably selected for their scientific value, but collectively they still make pretty pictures.

  19. Sci_Tchr

    NASA must repair Hubble!!!! Immagine how much science we would miss if they don’t.

  20. Kullat Nunu

    You could have mentioned that the ACS is kaput.

  21. Wicked Lad


    These massive bruisers have powerful stellar winds, and they also emit a flood of ultraviolet light. Both of these tend to push back the gaseous curtain enshrouding them, letting us peek in on the newborns.

    N00b question: How does this help us see them? Presumably, these forces push that curtain toward us as much as in any direction. Or do they push the gases back so much that they become significantly thinner?
    Kullat Nunu

    You could have mentioned that the ACS is kaput.

    Wah!! I looked it up, and it’s true!

  22. Ok, I hope this isn’t a stupid question but … what does this cluster look like to the naked eye?

    Is it just a white dot? Is it visible at all? Is it a faint smear?

    You wouldn’t see it — its magnitude is about +9, too faint to be seen with the naked eye, and even a bit dim as clusters go. In a small telescope, I imagine the cluster would be plainly visible even from the city, but of course you’d want a dark sky to see much of the nebula.

    I’d go out and contribute my own telescopic observations, but it’s at -61 degrees declination, so from where I live there’s always a pesky planet in the way.

  23. Lurchgs

    y’know – something like this would be *awsome* as an offering from Fathead

  24. Rystefn

    That’s awesome. I just found my new desktop (replacing the old back of Saturn pic you gave us a while back).

  25. Tom

    I don’t remember the author but Scientific American published an article on the supernova of 1987 that was actually exciting, the best piece of it’s sort I’ve seen, ever. Even today I can remember it almost verbatim.That started my interest in astronomy that remains.

  26. Phil B.

    God help me, but when I look at that photo I keep expecting Tom Bakers face to appear in the middle of it all.

    I’m a sad, sad person.

    (Beautiful pic btw)

  27. retardigrade

    NGC 3603 and environs has been one of my all-time MW favorites too. Always nice to see another great shot of it!

    Its an extravagant standout jewel adorning the spiral arms of our galaxy, a 1000+ member cluster which is still associated with its birth nebula estimated to contain a whopping 400,000 solar masses.

    The cluster’s single most dazzling member is itself worthy of hyperbole: from one study it appears to be a binary system comprised of two colossal heavyweights, pinning them at around 84 and 114 solar masses – the latter about as massive as stars can get. Neither of them can avoid core-collapse in their future, which we’ll see as supernovas. The fact that they are 20,000 light-years away may mean that the heavier member, at least, has already kaboombed, in which case the news of its demise may have been on its way since about the time our stone-age ancestors were still dealing with the last Ice Age.

    All of that, along with those strangely sculpted ionized clouds and possible supernova remnants which punctuate the scene (which might suggest even heavier stars have already blown themselves to bits, if the progenitor stars formed at the same time as the cluster we’re seeing now) would easily make it among THE current major attractions for any alien astronomers in the galaxy.

    But its the trunk-shaped photo-evaporation fronts that give the scene an immediate sense of cosmic vitality, in the visible action of a prodigiously massive young cluster wind upon its natal cloud-womb. Those magnificent comet head/tail-like structures, long recognized in earth-based astroimagery but made hugely famous by the spectacularly detailed Hubble shots of the Eagle Nebula over half a generation ago now (can it be???), are exemplarary testimony to the long-term dynamism that operates before our very eyes on the interstellar scale. The ‘towers’ in NGC 3603 are gargantuan too, something like a factor of 5 larger than the relatively ‘dainty digits’ in the Eagle. Those ‘wind-sock’-like structures evolve over the course of many tens of thousands of years.

    All of this beautifully presents, once again, proof positive piled onto a mountain of additional and mutually-corroborative bits of evidence from the sky alone, a bigger picture of natural reality that is vaster and more glorious by far than any preconceived artifact of the feeble human imagination. Any preconceived human belief (like young-earth creationism) must blanch and wither with a mere glance at such a magnificent image…if proponents did not so tightly shut their eyes and minds to the great truths nature freely delivers with the humblest of messengers: particles of light.

  28. zeb

    “it’s gonna asplode”

    Sounds painful to the posterior!

  29. Arthur Maruyama

    For Wicked Lad:

    Aside from the velocity of individual stars within the cluster, the stars collectively are pushing back the clouds more-or-less the same in all directions–although do note that the cluster may not be at the center of the interstellar cloud. As it happens we are fortunate to have this view of NGC 3603, but there are presumably more clusters which may have perhaps equally or more spectacular views but their arrangement of the interstellar clouds are such that we cannot see them as well or perhaps not at all. For example: there appears to be a cluster of stars in the Trifid Nebula:

    which we cannot see fully because of the intervening interstellar clouds which give this nebula its name.


    To retardigrade:

    Tell us that you are a professional writer, please? Such soaring prose must mean that you are a pro, or at least intend to become one. My dull explanations may provide some illumination, but your writing simply SINGS!


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