Momentum Conservation Debate

The cluster focuses on debates about conservation of momentum and energy in variable mass systems, particularly whether a spacecraft can accelerate by converting mass to photons without violating conservation laws.

📉 Falling 0.3x Science
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Comments
20
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5
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#3916
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Keywords

OCW I.e en.m i.e wikipedia.org momentum energy mass conservation motion uncertainty principle force releases stores

Sample Comments

ziofill • Mar 31, 2025 • View on HN

Energy conservation and momentum conservation are different

IshKebab • Sep 21, 2021 • View on HN

Yeah he said momentum, not energy.

a_t48 • Aug 10, 2021 • View on HN

Just turn the energy into mass, duh.

egdod • Oct 22, 2019 • View on HN

It could if momentum isn’t conserved.

0-_-0 • Sep 26, 2019 • View on HN

Wouldn't momentum transfer from the consumed mass slow it down?

monadic2 • Jun 4, 2020 • View on HN

It can if it loses mass, correct? Energy conservation would result in increased momentum.

asimpletune • Sep 8, 2018 • View on HN

Wait, there’s no conservation of energy?

sp332 • Sep 22, 2011 • View on HN

Wouldn't this also violate conservation of energy? A particle with any mass, traveling at the speed of light, would have infinite energy. And accelerating a particle to that speed would "push back" on the earth with infinite force, so it might also break conservation of momentum.

marcosdumay • Aug 1, 2014 • View on HN

"Convert energy to mass" does not make much sense. If you throw light away, it'll propel you.

hinkley • Oct 20, 2022 • View on HN

The mass+energy still have to sum up though, don't they?