Rotating Helix

I’m takin’ it easy for Lincoln’s Birthday (he was a distant relation, actually, so I deserve it). Look! A Spitzer image! And no, I’m not just logrolling for my friend Robert. I took a look at today’s press release, and I couldn’t find anything else to blog about, then…

I take a closer look. I thought I’d link to the Hubble Space Telescope picture of the Helix and make some kind of comparison. But when I skipped between the two images, I noticed that the two seemed to be rotated 90° with respect to one another. Odd. For a quick double-check, I took a look at Rob Gendler’s (as always gorgeous) picture of the Helix, and it seems to match Hubble’s.

Here, I’ll save you the trouble and link to an essentially equivalent picture (with the Hubble color scheme) from Travis Rector:

Yep, it’s rotated. Bizarre!

I mean, honestly, it’s not a big deal. But it might be considered a little confusing not to have imagery from the NASA Great Observatories lining up properly.

Otherwise, I was just going to note that it’s interesting how the exterior of the nebula shifts from red-yellow in the Hubble image to blue-green in the Spitzer view: purely a matter of convention, of course, since images are typically mapped by wavelength, with shorter-wavelength light being mapped to (ironically) cool colors and longer-wavelength light to (equally ironically) warm colors. The red haze at the center of the Helix in the Spitzer image indicates a source of small, warmed particles—interpreted to be colliding comets in the aforementioned press release.

The Hubble site offers a “tour” of the Helix, which is quite nice. Perhaps we&rsquo’ll be treated to a different tour in a future interactive—one which shows the nebula not just in optical light, but in its intriguing infrared emission as well.

Dark Matter Blobs!

Reporting from the American Astronomical Society meeting in Seattle, Washington… In a brand spankin’ new press release from Hubble, we have the first-ever “3D map of the Universe’s Dark Matter scaffolding.”

First off, the result is quite kewl. We’re beginning to map the stuff that “outweighs” ordinary matter by a factor of six to one. Great work, COSMOS team!

The above image isn’t the primary image released, but it’s the one with which I find the greatest fault. By abstracting the blobs of dark matter without any reference to scale whatsoever, we’re left with no sense of how large the object is that we’re looking at. The primary image that accompanies the press release improves on the problem by labelling slices at 3.5, 5.0, and 6.5 billion years ago, but the size of the image on the plane of the sky is left undescribed—although the caption does clarify that “Each panel represents an area of sky nine times the angular diameter of the full Moon.”

Images such as the one above do a disservice to public understanding of astronomers’ work by abstracting the result completely from reality. The lack of scale I already complained about, but I have other issues as well“ The use of isosurfaces is non-intuitive for the vast number of people. The inclusion of half a box around the data provides a sense of dimension but could also confuse people. And a meaningless background haze does nothing in service of the rest of the image.

Great science, bad picture.