Neptune: Now in HD

Post by Nic Quattromani:

This week we got a revolutionary new picture of another planet in our solar system, and while it’s not the planet with the most interesting surface features (or with surface features at all, actually), we nevertheless have the best view of Neptune since Voyager 2 visited back in 1989. Feast your eyes on this beautiful blue space marble:

Neptune from the VLT with MUSE/GALACSI Narrow Field Mode adaptiv
It has clouds and everything! Credit: ESO/P. Weilbacher (AIP)

This image was captured by the Chile-based Very Large Telescope of the European Southern Observatory—an organization which surprisingly does not appear to be affiliated with the ESA—using the miracle technology of adaptive optics. Here’s the gist of it: for ground-based telescopes, no matter how large you build them, the atmosphere causes distortions that put an upper limit on the resolution you can achieve. What adaptive optics does is compensate for that, measuring the characteristics of the pesky air we breathe and adjusting a computer-controlled mirror to compensate. ESO’s Very Large Telescope* makes these calculations one thousand times per second. To make things even more intense, and more like a Bond villain’s pet project, the calibration is done by shooting four lasers at high-altitude sodium particles, creating an artificial “Laser Guide Star” which reveals exactly how thermal layers and turbulence affect the passage of light at that moment. The results are extraordinary:


Neptune from the VLT with and without adaptive optics
Reminds me of the first time I put my glasses on. Credit: ESO/P. Weilbacher (AIP)

Now, using this technique to look at Neptune doesn’t reveal that much. It’s a giant ball of blue, as we expected. Since Voyager 2 no aliens have come by and painted graffiti on it (at least, not on the side visible in ESO’s image). However, according to ESO adaptive optics “will enable astronomers to study in unprecedented detail fascinating objects such as supermassive black holes at the centres of distant galaxies, jets from young stars, globular clusters, supernovae, planets and their satellites in the Solar System and much more.” So, that covers pretty much everything. If it’s in the sky, you can use adaptive optics on it.

These Neptune photos are a high-definition harbinger of what is to come. The universe is at our fingertips, and now, thanks to the awesome power of science (and lasers), we don’t even have to leave the atmosphere to take a good, sharp look at it.


* Makes me wonder if there’s a shadowy international consortium of bureaucrats whose job is to give government projects the blandest names possible. Here in the States we’ve got the Space Launch System, the Advanced Gun System, the Experimental Spaceplane 1,  and so on.

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