Timeline for Coord. system:collection of charts (local homeomorphisms to ℝ𝑛) for differentiable manifold 𝑀, frame:section of tangent vector fiber bundle over 𝑀
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 3, 2021 at 1:15 | vote | accept | uhoh | ||
| Feb 2, 2021 at 22:14 | comment | added | David Hammen | Those assumptions of a Newtonian universe with small relativistic perturbations are quite valid in the context of things in our solar system, where velocities are small compared to the speed of light and distances are large compared to the Schwarzschild radii of gravitational bodies. The fastest spacecraft will be the Parker Space Probe at perihelion, when it will move at 0.064% of the speed of light and be at two million Schwarzschild radii from the center of the Sun. | |
| Feb 2, 2021 at 22:09 | comment | added | David Hammen | On the other hand, for the next several decades, we can get away with the assumption of a Newtonian universe with relativistic effects as a small perturbative acceleration because, except for a few slow moving probes that have left / are leaving the solar system, we're stuck in our solar system. | |
| Feb 2, 2021 at 22:04 | comment | added | David Hammen | The distinction between coordinate systems, reference frames, and charts becomes important in general relativity and in cosmology. It is (IMHO) highly erroneous to say that a recently discovered galaxy is 13.26 billion light years away. It is even somewhat erroneous to that light from that distant galaxy took that much time to arrive at the Earth in that computing that age requires making various assumptions regarding the expansion of the universe. Multiplying that time span by the speed of light assumes a Newtonian universe in which 3D space is Euclidean and time is the independent variable. | |
| Feb 2, 2021 at 7:08 | answer | added | Ryan C | timeline score: 5 | |
| Feb 2, 2021 at 1:36 | history | edited | uhoh | CC BY-SA 4.0 |
added 366 characters in body
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| Feb 2, 2021 at 1:28 | history | asked | uhoh | CC BY-SA 4.0 |