I was just curious because if space can expand faster than light, doesn't that mean there will be a lot of space that we just can't see? Do objects just vanish because we can't see them? For instance, if a hypothetical alien lived in MACS0647-JD galaxy which is 13.3 billion light years away, wouldn't it's observable universe extend into space outside of our observable universe? Wouldn't that mean observable universes are infinite and share the same age? Is there anything that says space can't extend past where we can observe based on the speed of light?