Astronomers print 3D models of colliding solar winds

Solar wind models

The weird stellar winds of Eta Carinae are hard to visualize — so astronomers used a Makerbot to create 3D models that they could hold in their hands.

There's obviously tons of excitement about 3D printers as manufacturing tools. But personally, I've always been more interested in their use as an aid for thinking. In what situations is it easier to puzzle through a problem by printing and physically handling it?

One example: Eta Carinae's incredibly complex solar winds. A "supermassive binary star system" that flared up in 1843, it became the second brightest thing in the heavens after Sirius. It slowly dwindled in size, but continued to flare up again and again — with complicated fluctuations in the amplitude of its brightness. What was causing these fluctuations? Why would it get brighter during one flare-up, but less bright during another?

Thomas Madura and a team of NASA scientists recently figured it out. Astronomers had deduced a while ago that the two stars of Eta Carinae are very close together (roughly the same distance as Mars and the sun), and each one exudes a very dense solar wind. Those winds interact with each other, so astronomers had long suspected that's what caused the fluctuations. But it was awfully hard to parse how those interactions worked.

That's what Madura and the team finally did. They gathered data from various observatories and created 3D models that you can spin around and view from various angles. (Literally, you can do it, too. The 3D models are embedded in the PDF copy of NASA's paper. Download the paper, open it in Adobe Acrobat, click on any image, and it pops into 3D — so you can rotate and swivel it. Check it out!)

Then they made their models physical. As MIT's Tech Review reports:

The team has gone even further. Having created a virtual 3-D model, they print it using a standard 3-D printer, a MakerBot Replicator 2X.

They say this provides even more insight into what's going on. "The ability to hold and inspect the 3-D printed models provides a new perspective on the WWIR's geometry and an improved sense of the scale of the different structures," they say. In particular, they say the model allows them to appreciate just how large the shockwave is compared to the stars and the distance between them.

The 3-D models also give a clearer sense of the line-of-sight view that astronomers get from Earth. The shockwaves inside the nebula, and the structures they create, can absorb radiation and prevent it reaching Earth. Having a clear line of sight shows just how sensitive this is to astronomers' point of view.