First one that got me was the black hole. If I dig a hole in the ground, is that not really a hole? If I find a hole in your logic is that not a hole? If I model the flow of charge with positive ‘holes’ between electrons, are they not holes? And… do people really commonly think a ‘black hole’ is a traditional sort of hole? ‘Hole’ seems a perfectly reasonable name for what it really is.
Now what a black hole really is is fascinating stuff, but not in a “see, people are so ignorant to think it’s a hole” kind of way.
Even worse, we don’t know what black holes really are.
Is there a discontinuity in spacetime? Is the discontinuity point-like or spherical, or even toroidal? Do physics even exists within? Is “within a black hole” even a reasonable concept? We don’t know! We’re still arguing about wether black holes can delete information from existence.
My favourite black hole fact, coming from the character of the space-time tensor and how it changes, is that as you approach a black hole, time goes sideways.
I don’t think my lecturer put it quite that way, but he showed that as you get close, the time dimension comes to look like a space dimension in the tensor, and the space dimension that points into the black hole, looks like a time dimension!
First one that got me was the black hole. If I dig a hole in the ground, is that not really a hole? If I find a hole in your logic is that not a hole? If I model the flow of charge with positive ‘holes’ between electrons, are they not holes? And… do people really commonly think a ‘black hole’ is a traditional sort of hole? ‘Hole’ seems a perfectly reasonable name for what it really is.
Now what a black hole really is is fascinating stuff, but not in a “see, people are so ignorant to think it’s a hole” kind of way.
Even worse, we don’t know what black holes really are.
Is there a discontinuity in spacetime? Is the discontinuity point-like or spherical, or even toroidal? Do physics even exists within? Is “within a black hole” even a reasonable concept? We don’t know! We’re still arguing about wether black holes can delete information from existence.
My favourite black hole fact, coming from the character of the space-time tensor and how it changes, is that as you approach a black hole, time goes sideways.
I don’t think my lecturer put it quite that way, but he showed that as you get close, the time dimension comes to look like a space dimension in the tensor, and the space dimension that points into the black hole, looks like a time dimension!
Yeah, time-like paths are mind bending.
I’ve always though about that as the interior of the black hole has been left behind in the time direction, like a sausage casing.