Spectacular VISTA of the Tarantula

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Aug. 11 2010 10:31 AM

Spectacular VISTA of the Tarantula

Ever wanted to see a Tarantula up close? Up really close? Here's your chance!

Phil Plait Phil Plait

Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death from the Skies!  

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[Click to hugely enarachnidate, or grab the atomically-mutated, 130 Mb, 9000 x 12000 pixel megaspider version here. But be ye fairly warned, says I: you'll lose your afternoon looking at it.]

That is a new image of the Tarantula Nebula (ha! Got you!) from the European Southern Observatory's VISTA survey telescope in Chile. The telescope can see in the near-infrared, just outside the range of our human vision, and is being used to map a big chunk of the southern sky.

The Tarantula is a sprawling star-forming region in the Large Magellanic Cloud, a small companion galaxy to our own Milky Way Galaxy. Of course, "small" is a matter of perspective; the LMC is still tens of thousands of light years across and has several billion stars in it. From its distance of 180,000 light years, the LMC appears as a smudge in the sky to the unaided eyes of southern observers.

In astronomy terms the image above is huge; it covers a square degree of sky, several times the area of the full Moon! However, in real terms, if you lived in the southern hemisphere and went outside on a clear night, you could block out the entire region of the picture with the tip of one finger held at arm's length. But VISTA's 4-meter mirror has fine vision, and the image is crammed with detail. It's hard to see in the embedded image above because I had to compress it wildly to have any hope of letting y'all see it here. The higher-resolution images, however, are simply spectacular! Here's a taste; I cropped out a small portion:

Wow! Mind you, this is from the medium resolution image! It's a section to the right and a bit below the nebula proper. And while it's crammed with stars, gas, and dust, I didn't pick it randomly. It has one other object in it of note: Supernova 1987A, an exploded star whose light reached us on February 23, 1987. It was, for a few shining moments, among the brightest objects in the entire Universe... but now is lost in a sea of stars, in a small section of one image of a small galaxy.

The Tarantula Nebula is a forbidding object. It's well over 600 light years across, has millions of times the Sun's mass worth of gas jammed into it, and is forming stars so furiously that astronomers think it may actually be creating a globular cluster, a spherical ball of hundreds of thousands of stars. You may have heard of the Orion Nebula, one of the largest and brightest of all nebulae in the Milky Way. Well, the Tarantula is thousands of times more luminous; if it were as far away as the Orion Nebula, the Tarantula would be bright enough to cast shadows on the ground!

VISTA will eventually map out 184 square degrees of the sky, which is truly an enormous swath of the sky at this resolution. It will guide astronomers for years to come, giving us a highly-detailed and, yes, beautiful map of stars, galaxies, and nebulae... and best of all, stuff we're not even aware of yet. Big surveys always help us piece things together, put the details into perspective.

But oh, sometimes, the details themselves are worth gawking at.

ESO/M.-R. Cioni/VISTA Magellanic Cloud survey. Acknowledgment: Cambridge Astronomical Survey Unit



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