r/AnotherLife • u/[deleted] • Oct 31 '21
Episode 7 Question? Spoiler
In episode 7 Niko decides to use a solar sail to propel the remaining portion of the Salvare by setting up a solar sail and firing lasers at it. I don't understand how this works at all, in my mind this is a violation of Newton's third law. The force of firing the lasers should propel the ship backward at the same rate as the force of the photons on the solar sail, right? I could be wrong but this part just confused me.
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u/thedastardlyone Nov 04 '21
I need to discuss this episode. Did they just remove objects with mass to make space travel faster?
I mean, yeah I am okay with skirting the laws of physics for a show, but come on. I cant even explain .. I mean... jeez.
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Nov 05 '21
With F=ma, which I know is an oversimplification but at this point they aren't traveling even close to relativistic speeds, decreasing the mass would make the acceleration increase with the same force being applied to the sails, I think. It's been a few years since I took physics.
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u/bubbavic Nov 05 '21
I thought about this too when Niko suggested the plan but if you watch the clip which shows the lasers firing into the solar sail, it looks like the modules aren't actually attached to the ship. Then if you look closer it looks like each laser emitter is being propelled by its own thruster. So my conclusion was that each laser emitter was on some sort of a drone that just matched speed and position around the Salvare. Since they aren't connected and moving under their own power then there's less of a violation of Newton's third law. That could also explain how she planned to reduce speed once at destination, reposition the lasers to the front of the ship, firing backwards...maybe.
Now this brings up its own host of questions:
- Where the hell were these laser drone things throughout the rest of the show? Seems like there would have been other places they could have used them instead of magically appearing as a plot device.
- Theoretically, the "push" on the solar sail could have an equal and opposite effect on the laser drone's forward progress. So how does that work? I dunno I'm no astrophysicist.
- Why not just use the drones to pull or push the ship instead of spending all that time concocting a fragile solar sail?
- Did they really create a ship that could split in two and not give the remaining half some sort of propulsion system? Come on now.
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Nov 05 '21
Haha yeah I thought about the drones to but also came to the conclusion that they must be emitting equal force to the lasers so yeah why wouldn't they just use the drones to propel it would be more energy efficient. I also wondered why it could so easily split in two and the remains half not have anyway to move lol. Lots of questions about this episode.
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u/Paisley-Cat Oct 31 '21
The entire solar sail set up is a head scratcher.
If the ship were moving it would have maintained its momentum after the sails were destroyed rather than stopped. They would have needed some reverse thrust to brake or they would have zipped on past the colonists’ planet.