In fairness to them, there is no gravity anywhere. Only spacetime, the shape of which determines the extent to which it looks like there is a force at work, a force we call gravity.

When the presence of a mass curves spacetime, we call the resulting effect “gravity.” https://twitter.com/andmoo22/status/1349561531986489345

Shout out to the men who are explaining my tweet about gravity to me.

My dissertation was called “Cosmic Acceleration as Quantum Gravity Phenomenology” and I passed a qualifying exam in astronomy and a qualifying in physics.

Gravitation was one of my specialities.

You all really thought I didn’t understand a high school level textbook discussion of gravity and where it went erong? Literally my phd is in gravity

Shout out to the one guy who knew to ask questions! Which I will answer. Yes my answer was based on general relativity and quantum gravity does go beyond that and may involve a graviton :-) https://twitter.com/umairmufti/status/1349794658260381696

Anyway what the textbook should have said, to both be accurate and prep students to move beyond the Newtonian framework, is that the further an object gets from other massive objects the less it is drawn to those massive objects. So astronauts in orbit feel earth’s pull less.

Coincidentally part of the problem with what the book said was that astronauts in orbit are still experiencing earth’s pull in a very obvious way: the orbit.

But I’d be willing to argue that if we taught curved Spacetime earlier, that would make this point more intuitive

“But we can’t confuse them before they have a solid understanding of Newtonian mechanics!”

Eh. We write about general relativity in articles for general audiences all the time. Then we let students down by not discussing it in undergrad classes.

Also what if we started teaching students early on about how theories have scales of relevance. Like what if that was lecture one: Newton’s gravity is useful but limited. We will start with developing an understanding of the limited scenarios where it is useful!

Graviton are very much hypothetical at this point. https://twitter.com/Schmaniel/status/1349803248765562883

The main reason to teach Newtonian mechanics first is that it is mathematically simpler than GR and allows students to develop a vocabulary (potential energy, angular momentum, etc) without worrying about a certain level of mathematical understanding/sophistication.

This is a fair point although tangential to the one I was making in that particular tweet but highly related to the point I made in the next one. https://twitter.com/nathairnimheil/status/1349805929001332736

My best friend drew a really nice figure for my book (out March 9) that helps people understand this idea of “free fall” but I know I can’t tweet it right now

I read the textbook as trying to provide a “less gravity” scenario but yes if they really meant to focus on free fall

then a Newtonian framework is even less useful to students in the long run