Difficulties with interstellar travel

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Discussion Overview

The discussion revolves around the concept of mass increase in atoms when a spacecraft travels at relativistic speeds through interstellar space. Participants explore the implications of relativity on the interaction between the spacecraft and diffuse atoms, primarily hydrogen, and the resulting radiation effects. The scope includes theoretical considerations of relativity and its application to interstellar travel.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions how mass is increased for atoms when struck by a spacecraft traveling at nearly the speed of light, referencing the abundance of hydrogen in the universe.
  • Another participant explains that in the frame of the atom, it is moving towards the ship, and vice versa, highlighting the role of Galilean relativity and the additional considerations introduced by special relativity.
  • A different participant asserts that the change in mass is not due to the structure of the atom but rather a result of Lorentz contraction and time dilation, emphasizing that the atom's structure remains unchanged in its rest frame.
  • Another contribution distinguishes between "relativistic mass," which increases with velocity, and "rest mass," which remains constant, suggesting that the concept of mass in relativity is nuanced and involves different definitions.

Areas of Agreement / Disagreement

Participants express differing views on the nature of mass in relativity, particularly regarding the concepts of relativistic mass versus rest mass. There is no consensus on the implications of these concepts for the scenario presented.

Contextual Notes

Limitations include the potential confusion surrounding the definitions of mass in relativity and the implications of relativistic effects on particles. The discussion does not resolve these complexities.

vincentm
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According to Relativity, if a ship traveling at nearly the speed of light through interstellar space diffuse atoms (mostly Hydrogen, becase simply that is the most abundant atom in the universe, right?) would strike the front of the ship with increased mass, causing radiation. My question is how is this mass increased on the part of the atom?Thank in advance guys :smile:
 
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vincentm said:
According to Relativity, if a ship traveling at nearly the speed of light through interstellar space diffuse atoms (mostly Hydrogen, becase simply that is the most abundant atom in the universe, right?) would strike the front of the ship with increased mass, causing radiation. My question is how is this mass increased on the part of the atom?


Thank in advance guys :smile:


If the ship is traveling fast relative to the atom, measured in the atom's frame, then the atom is traveling at the same speed in the opposite direction, measured in the ship's frame. That's just good old Galilean relativity as when you're driving along and you see the telephone poles moving backwards relative to you. What special relativity adds is that each of the two, ship and atom, experiences the other as Lorentz transformed.

BTW, I'm moving this thread to the relativity forum, where it belongs.
 
vincentm said:
According to Relativity, if a ship traveling at nearly the speed of light through interstellar space diffuse atoms (mostly Hydrogen, becase simply that is the most abundant atom in the universe, right?) would strike the front of the ship with increased mass, causing radiation. My question is how is this mass increased on the part of the atom?


Thank in advance guys :smile:
The change in mass is due, not to the stucture of the atom (or any particle for that matter) but is due strictly due to a combination of Lorentz contraction and time dilation. Recall that there is a frame in which the atom is at rest and in that frame the particle has a given structure which will not change when your frame of reference changes.

Pete
 
vincentm said:
According to Relativity, if a ship traveling at nearly the speed of light through interstellar space diffuse atoms (mostly Hydrogen, becase simply that is the most abundant atom in the universe, right?) would strike the front of the ship with increased mass, causing radiation. My question is how is this mass increased on the part of the atom?


Thank in advance guys :smile:

You should note that there are two sorts of mass in relativity. There is "relativistic mass", which is rather outdated, which increases with velocity. There is also rest mass, which does not increase with velocity.

See for instance:

http://math.ucr.edu/home/baez/physics/Relativity/SR/mass.html

"Does mass increase with velocity"
 

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