Big heavy glass swirled sphere with flat bottom

Hello, check out this huge heavy glass sphere. It has a small hole on the bottom and I was able to balance it on a flashlight as you can see in the photos. It’s pretty cool and I was wondering if anyone knows anything about it? Maybe It use to sit on a stand with a light that lit up underneath? There is no markings on it that I can find and it appears to be handmade. The thing weighs a ton, but it is not completely solid glass. I can see into the small hole on the bottom and it is hollow, but very thick glass. Any info would be greatly appreciated! Thank you!