What Everyone Gets Wrong About Gravity

What Hacker News said

Strong rec fsh · 2022-03 · on “We're building computers wrong [video]”

I think he is easily one of the smartest people on YouTube and is producing some of the very best videos. He is also a brilliant educator. For examples, his videos on special [1] and general relativity [2] were real eye-openers for me, even though I have studied physics and have seen this stuff explained a million times before. What I really don't like are the new video titles. At some point he started A/B testing them to maximize his revenue. He even made a video about it [3]. Of course, this selects for the most outrageous clickbait in order to get that sweet engagement. I am starting to wonder if he took into account, how much this is starting to alienate long-term followers. [1] [LINK] [

Recommends doomrobo · 2020-10 · on “Gravity is not a force – free-fall parabolas are straight lines in spacetime”

When you are at rest on the surface of the earth, you’re actually accelerating. I barely understand it but veritasium explains it in the newest vid [this video]

Recommends vl · 2020-10 · on “Gravity is not a force – free-fall parabolas are straight lines in spacetime”

Original page kinda doesn’t explain the idea in simple terms. This Veritasium video gives detailed “popsci” explanation: [this video]

Recommends j1vms · 2020-10 · on “Gravity is not a force – free-fall parabolas are straight lines in spacetime”

Here's [0] a bit more thorough explanation of this concept for those who are interested. [0] [this video] (Veritasium on Youtube: Why Gravity is NOT a Force @ 8:24)

Recommends metrognome · 2022-04 · on “Weightless cats – Do space cats land on their feet? (2011) [video]”

While falling, the cat is in an inertial reference frame, so it is not accelerating. The ground is actually accelerating upward at 9.8 m/s2, counteracting the flow of spacetime. This Veritasium video gives an intuitive explanation: [this video]

Recommends darken · 2023-04 · on “Why Gravity Is Not Like the Other Forces”

Respin of a comment I posted a while back: This is what helped me wrap ahead around the fact that gravity "is not really a force": when you are in free fall you feel 0 acceleration. You appear to be accelerating relative to the ground-- but you're actually motionless in an "inertial reference frame". (Similar to how the astronauts on the ISS don't "feel" acceleration despite accelerating rapidly relative to the earth.) The "force" of gravity is often modeled as "gravity pulling you down" and the ground "pushing you back up". This works mathematically, but isn't quite logically consistent. In reality, on the ground you're in a region of warped spacetime, so you feel constant upward accelerati

Recommends qnleigh · 2025-05 · on “Dead Stars Don’t Radiate”

Ah yeah there are multiple definitions of 'acceleration' here. Unruh radiation occurs when you're not 'in an inertial reference frame,' loosely meaning that you feel acceleration. So in a rocket in space or (presumably) standing on Earth's surface. What you say makes intuitive sense, but it was actually the opposite logic that lead Einstein to his general theory of relativity. Here's a slightly dorky but very good Veritasium video that explains this issue and general relativity [this video]

Cites gilgoomesh · 2020-10 · on “Gravity is not a force – free-fall parabolas are straight lines in spacetime”

Energy is Force times Distance. You're not moving (even though you're accelerating) so there's no energy expended. See Veritasium's video at 10m17s: [this video] He addresses that basic science makes this confusing because there's a curvature term that is usually left out of acceleration equations which balances out when you're accelerating along your curvature (e.g. against gravity), instead of along your spatial coordinates.