Activity for Vancalar‭

Type	On...	Excerpt	Status	Date
Question	—	How do we know that distant stars and galaxies are real? In some universe,with physical laws the same as in ours, our world is some kind of "lab environment". Our solar system is enclosed in a balloon-like sphere with a radius of a few light-days around the sun (just big enough to contain Oort clouds and all long-period comets). The inner side of the sphe... (more)	—	over 6 years ago