[BikerNYC]

At what point is something massless?

Well, I think if something can attain the speed of light, it's massless.

[sirchtruth]

Well, I think if something can attain the speed of light, it's massless.

That's an interesting point. The only prblem I see is light acts like particles or waves and this article argues particles have mass?

[Victor]

"...Well, I think if something can attain the speed of light, it's massless....."

Einstein, I believe, basically theorized that as matter approaches the speed of light, its mass becomes infinite.

[Liver]

It's all relative. It depends on how many dimensions there are in reality, and how you define mass. It could be that Einstein only caught on to a tip of the iceberg--so to speak. If we discover other dimensions, it could redefine our concept of matter, reality, etc.