So much for sending my questions about cosmology and quantum mechanics to Brian Greene … the following email got kicked back from www.briangreene.org because the mailbox is full. Popular guy.
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Hello Brian,
I’m a huge fan of “The Fabric of the Cosmos” but, as a non-scientist, I struggle to understand physics. There are several questions that particularly irk me and, though I know you are probably deluged with such questions, I thought I would hazard an email.
1. Regarding space-time, is it really true that the past still exists and could be visited if we were able to move sufficiently far through space? This seems to be one implication of your “time-space-loaf” image, but perhaps I’m way off base here.
2. Re: quantum entanglement, I understand that measurement of spin, for instance, of an entangled particle instantaneously causes a correlated behavior in a partner particle, but, while I have heard numerous times that it is this measurement that causes one particle to “choose” a property, I do not understand how this is known … in other words, how can we know that it is the measurement that it is causing the choice, if we are not seeing the state of the particle before that measurement?
3. If we on Earth do not have a privileged position in the universe (i.e., we’re not “at the center of the universe”), how is it that we’re able to make determinations about the age of the universe? In other words, how can we see to the edge of the universe in all directions? And, as I think about it, perhaps it’s not relevant whether we’re at the center or not for the purposes of this question. I understand that, in looking through space we’re looking back in time, but aren’t there limits to how far we can see? So, in that case, how do we know we’ve reached “the edge” of space?
These may well be ridiculous questions, but I would be very appreciative of any response you can provide.
Regards,
Alex Stevenson