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When the original paper about planet 9 being a black hole came out a year ago, everybody thought it was a cool-sounding but just completely wild idea -- both ph

by knzhou 6y ago

When the original paper about planet 9 being a black hole came out a year ago, everybody thought it was a cool-sounding but just completely wild idea -- both physicists and pop science articles. Not impossible by any means, but not within the top 250 new physics ideas in plausibility. Then the discussion died down. I figured it would end up being one of those forgotten but cool gems. Then the most authoritative string theorist in the world, who hasn't worked on anything relating to experiments in decades, suddenly writes a very short, simple, single-author paper to use this idea to promote Yuri Milner and Mark Zuckerberg's space probes. Now it's the conjunction of two crazy ideas, and it's really taking off. I just don't know why this is happening, or what to make of it.

qubex 6y ago
Of course if there was enough dust in interstellar space to reflect a laser beam (as happens when we see the traces of glowing beams shone through carbon dioxide gas) we could just prove the heavens with laser beams until suddenly we saw a beam bend. Unfortunately that isn’t the case so we have to fling stuff at it and see if they veer off track.
- Sharlin 6y ago
  We do have microlensing though: https://en.wikipedia.org/wiki/Gravitational_microlensing https://en.wikipedia.org/wiki/Gravitational_microlensing
- robocat 6y ago
  You can’t easily linearly scan space for a moving target, among other show-stopper problems.
  - qubex 6y ago
    No, but since using satellites on trajectories you hope will be perturbed is essentially ‘scanning’ anyway, it would be preferable to do it with a light-beam than with physical objects.
T-A 6y ago
I don't know about taking off, but there is an obvious reason for anyone interested in quantum gravity to like the idea of having a small black hole in the solar system: it holds out hope that the subject could become experimentally accessible.
pontifier 6y ago
I'm not going to claim I was the first to suggest it, but I've been expecting something like this for a long time... at least since 2015 https://twitter.com/pontifier/status/581538570038460416?s=20 https://twitter.com/pontifier/status/581538570038460416?s=20

by knzhou 6y ago

qubex 6y ago

Of course if there was enough dust in interstellar space to reflect a laser beam (as happens when we see the traces of glowing beams shone through carbon dioxide gas) we could just prove the heavens with laser beams until suddenly we saw a beam bend. Unfortunately that isn’t the case so we have to fling stuff at it and see if they veer off track.

Sharlin 6y ago
We do have microlensing though: https://en.wikipedia.org/wiki/Gravitational_microlensing https://en.wikipedia.org/wiki/Gravitational_microlensing
robocat 6y ago
You can’t easily linearly scan space for a moving target, among other show-stopper problems.
- qubex 6y ago
  No, but since using satellites on trajectories you hope will be perturbed is essentially ‘scanning’ anyway, it would be preferable to do it with a light-beam than with physical objects.

T-A 6y ago

I don't know about taking off, but there is an obvious reason for anyone interested in quantum gravity to like the idea of having a small black hole in the solar system: it holds out hope that the subject could become experimentally accessible.

pontifier 6y ago

I'm not going to claim I was the first to suggest it, but I've been expecting something like this for a long time... at least since 2015 https://twitter.com/pontifier/status/581538570038460416?s=20 https://twitter.com/pontifier/status/581538570038460416?s=20