There's other life on other planets. There has to be. Our universe is too great a size for Earth to be the only planet with life logically, and to think otherwise is conceited. Nobody knows for sure, and anything can happen, so it could be possible that Earth IS the only planet with life. (But I don't think so.) But do I think that aliens have ever visited Earth? No. Of all places to visit, why Earth? But, then again, anything can happen.