Newtonian tidal gradients and disruption scale
Tides arise from gravitational acceleration differences across an extended body.
Key knowledge
Tides arise from gravitational acceleration differences across an extended body. For a distant point mass M and a small displacement ξ from a freely falling body center, differential acceleration is Δg≈(GM/d³)[3n(n·ξ)−ξ]. It stretches along the mass direction and compresses transversely. Comparing it with a body's self-gravity gives a disruption-distance scale proportional to R(M/m)¹ᐟ³.
Values and equations
Δg≈(GM/d³)[3n(n·ξ)−ξ]; d_disruption∼R(M/m)¹ᐟ³
- Δg
- differential gravitational acceleration m s⁻²
- M,m
- source and distorted-body masses kg
- d,R,ξ
- source distance, body radius and displacement vector m
- n
- unit vector toward the source 1
- G
- gravitational constant m³ kg⁻¹ s⁻²
Conditions and scope
- Newtonian weak-field gravity, |ξ|≪d, n directed from the body center to the source; subtract the center's common acceleration.
- A Roche/disruption coefficient depends on structure, rotation, orbit and material strength. The scale is not an exact universal boundary, and close black-hole encounters can require relativistic tides. Dissipative orbital evolution needs material response in addition to a conservative gradient.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Read the finite-extent differential-gravity explanation, R(M/m)¹ᐟ³ scaling and close-black-hole GR qualification. The tensor expression is the disclosed first derivative of Newtonian point-mass acceleration. Excluded dated rates, instrument claims and unqualified observational-identification statements.
2026-10-10 · Independent AI editorial review: All44 exact root-authored compact records, equations/variable units/conditions and140 origin edges accepted after independently reading final6/18 with bounded primary bodies and matching prior38/122 scientific fingerprints unchanged. Exact claim/edge review is distinct from combined inventory scope and separate CLE26 approval; no entire cited books or old-corpus experimental revalidation is asserted. Receipt: cosmos-completion-independent-content-and-inventory-review.1.
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