Ten years ago, I spent an unforgettable summer as a research intern at the Lunar and Planetary Institute, just down the street from Johnson Space Center in Houston, TX. I remember during my first week or two there, we went over to JSC and explored some of the research buildings there (two or three of the interns worked with researchers on-base, part or most of the time.) We put on our clean-room suits and toured the Lunar Sample Laboratory and peered at the under-construction Stardust Laboratory, set to receive cometary and interstellar dust particles from the Stardust mission.

Although I was more interested in the Lunar Sample Laboratory tour (and JSC’s amazing collection of Antarctic meteorites), Stardust sticks in my mind because of one thing: aerogel:

[Aerogel] is a silicon-based solid with a porous, sponge-like structure in which 99.8 percent of the volume is empty space. By comparison, aerogel is 1,000 times less dense than glass, which is another silicon-based solid.

We had an opportunity to handle a small piece of aerogel that day. I remember it so clearly because I’ve never seen anything like it. You could barely SEE it, for start; the edges were almost invisible, and weight was imperceptible. It sat on my palm only slightly visible, glowing peachy-warm and smoky-blue, like a piece of opaline glass, without the edges.

If you can imagine holding a cloud in your hand, I think that’s the best comparison I can come up with to describe the sensation.

I’ve never held something so insubstantial, so barely there, so barely real — yet real to the touch. Aerogel supports heavy weight, insulates 39 times better than the best fiberglass insulation, and yet its presence can barely be seen, and felt by touch, not by weight. It’s a strange little memory for me, but quite vivid….