xionzui

joined 1 year ago
[–] xionzui@lemmy.world 1 points 1 year ago (1 children)

It is! I also found this video later that I think does a better job of explaining reflection: https://youtu.be/1n_otIs6z6E

[–] xionzui@lemmy.world 1 points 1 year ago

That was always my assumption about why it happened, but it turns out that’s not the case at all: https://youtu.be/CUjt36SD3h8

[–] xionzui@lemmy.world 8 points 1 year ago* (last edited 1 year ago) (3 children)

Reflections involve the material absorbing and re-emitting photons back the other direction.

The curvature of light from gravity is actually space-time itself being curved by mass. The light continues on a straight path through a curved space-time. It looks like it changes direction from the outside, but that’s just the shape of the universe in that area.

That’s why we feel gravity. The space-time around earth is curved inward, so going forward in time would actually mean falling towards the center if we were stationary in space. The ground is constantly accelerating us upwards. Light does not get accelerated that way, so it follows the curvature.

If you want to get really deep into the reflection topic: https://youtu.be/rYLzxcU6ROM

[–] xionzui@lemmy.world 13 points 1 year ago (2 children)

In aggregate, yes, but any individual wave of light is still traveling at c. You get the appearance of a slower wave because secondary waves are generated that cancel the original one in such a way that it makes a combined wave that appears to be slower.

[–] xionzui@lemmy.world 15 points 1 year ago (11 children)

I’ve been trying to wrap my head around this part and what it means for cause and effect for a while. I think Feynman said something like a photon is only ever emitted when the source and destination agree to exchange one. Which makes sense if the exchange is instantaneous to the photon. But how can billions of years pass for us in the mean time?

[–] xionzui@lemmy.world 122 points 1 year ago (34 children)

To be pedantic, photons never accelerate. They only ever travel at one speed in one direction

[–] xionzui@lemmy.world 8 points 1 year ago

They tried it in Vietnam and discovered the lower iq recruits were more trouble than they were worth and made the military run worse overall, so it’s probably unlikely to happen again

[–] xionzui@lemmy.world 3 points 1 year ago

For Windows, WizTree because it’s extremely fast. For Linux, I like ncdu

[–] xionzui@lemmy.world 2 points 1 year ago

I use backupninja for the scheduling and management of all the processes. The actual backups are done by rsync, rdiff, borg, and the b2 tool from backblaze depending on the type and destination of the data. I back up everything to a second internal drive, an external drive, and a backblaze bucket for the most critical stuff. Backupninja manages multiple snapshots within the borg repository, and rdiff lets me only copy new data for the large directories.

[–] xionzui@lemmy.world 3 points 1 year ago

It is definitely very cool

[–] xionzui@lemmy.world 2 points 1 year ago

ROCK AND STONE, YYYYYYEEEEAAAHHH

[–] xionzui@lemmy.world 1 points 1 year ago (2 children)

That would be Albedo from Overlord

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