# Brian Cox on Reddit (u/ProfessorBrianCox)

Part of Scientists on Reddit, researched with Autumn (https://www.autumn.ai) from public sources. Updated 2026-11-07. Interactive version: https://www.autumn.ai/resources/scientists-on-reddit/brian-cox

Brian Cox: Particle physicist and BBC presenter.

- Reddit account: [u/ProfessorBrianCox](https://www.reddit.com/user/ProfessorBrianCox/) (Personal account)
- How we know it's theirs: [The 2022 r/space AMA, posted from this account](https://www.reddit.com/r/space/comments/t5ur10/)
- Where they post, in the records we retrieved: r/space (41), r/IAmA (39)
- Known activity in the posts we found: 2018 to 2022
- Wikipedia: https://en.wikipedia.org/wiki/Brian_Cox_(physicist)

## Moments

### u/ProfessorBrianCox in r/space, Mar 3, 2022 · Explains things

Replying to a redditor:

> If you could eat anything forever, what meal would you take on a trip to the inside of a black hole?

> It depends on the mass of the black hole. For a small black hole you have less time before you meet the end of time at the singularity and so maybe a quick curry, whereas for a supermassive black hole you'd have plenty of time for a full tasting menu with wine pairing.

Full thread: https://www.reddit.com/r/space/comments/t5ur10/comment/hz7h51u/ · 149 points as of Nov 7, 2026

### u/ProfessorBrianCox in r/space, Mar 3, 2022 · Explains things

Replying to a redditor:

> If photons have no mass, why can they not escape the gravity of a black hole 🕳?

> A black hole is essentially pure spacetime geometry, and the paths of photons 'follow' the geometry as it were. There are lots of ways of thinking about this. One is to use the equivalent principle, If you fire a laser beam horizontally in your room now, it actually 'falls' to the ground at the same rate as anything else you drop (neglecting air resistance). Einstein would say that a way to think about this is that the ground is accelerating upwards to meet the light beam. You don't see it curve of course from your perspective because it's travelling very fast. The basic point is that gravity is only associated with mass alone in Newton's theory, which isn't right! Einstein tells us that gravity is the curvature of spacetime, and everything responds to that.

Full thread: https://www.reddit.com/r/space/comments/t5ur10/comment/hz7izei/ · 33 points as of Nov 7, 2026

### u/ProfessorBrianCox in r/space, Mar 3, 2022 · Explains things

Replying to a redditor:

> If the most efficient shape is a sphere, is the center of a singularity a spherical mass or a spherical absence of matter?

> The singularity inside a Schwarzschild black hole (not spinning) is actually a moment in time - the end of time in fact. it's not a place in space. Inside an eternal Kerr (spinning) black hole it's a ring.

Full thread: https://www.reddit.com/r/space/comments/t5ur10/comment/hz7hezc/ · 50 points as of Nov 7, 2026