| Unlike photons, axions would pass directly through the wall to the other side. |
| Axions, if they exist at all, do so in our ordinary dimensions, but they are stable neutral particles. |
| Since axions can be produced from light, the sun and other stars should generate them copiously. |
| Since the wall is opaque, it should block the x-rays completely. However, x-rays are high-energy photons, so if PVLAS is producing axions, some of these photons should also turn into axions along the way. |
| These axions could accumulate around a black hole and extract energy from it. |
| Axions, if they exist at all, do so in our ordinary dimensions, but they are stable neutral particles, and as such they wouldn't make any tracks in a bubble chamber at all. |
