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JannaLevin12 karma

Love black hole questions. We don't really know what's inside a black hole. If we trust Einstein's theory all the way through, then we argue space and time sort of switch places inside. This means you are forced toward the singularity at the center as surely as you are forced forward in time. And there you will be crushed to death.

JannaLevin11 karma

We really need to think of motion as relative. So we always have to ask, how fast is something moving relative to what? If you imagine an astronaut floating in empty space, there is no meaning to her absolute motion. Someone else may believe she's cruising past them at the speed of light. But she will be convinced she's still and the other guy is moving past her.

JannaLevin10 karma

These days people talk more about a landscape. So instead of imagining that there was nothing before the big bang, we wonder if there is a landscape of spacetime. Occasionally on that landscape a patch gets caught in a high energy state and bubbles off into a big bang. This is multiverse view in which there are many universes and the conditions in each may be different.

JannaLevin9 karma

Yes. But on the other hand, the signals we've sent into space have only gone about 70 light years, a little more. I would be shocked (and excited) to discover there is intelligent life that close by, just in our backyard, and that the lifeforms have two eyes and a nose, and that their industrial revolutions coincides so closely with ours.

JannaLevin8 karma

The original work from Hawking and others tried to ask how a universe can come from nothing. To do this, they imagine a space of possible universes -- of possible spacetimes -- and they ask the probability for one of them to pop out of the virtual quantum sea and become real. So there is a virtual spacetime. Super abstract and fun question to start us off.