Earlier quoted context omitted.
not so much protons (which would be a problem, but could at least notionally be deflected), but atoms.
An hydrogen atom and a proton are roughtly the same thing, right?
A proton is a hydrogen ion and isotope.
Relativistic Spaceship
151–160 of 500 posts
Re: Relativistic Spaceship
#152Earlier quoted context omitted.
I suppose you would also have to worry about surviving the trip - every atom in the interstellar medium would damage your ship, likely penetrating the entire way through, and electromagnetic repulsion would only work with charged particles.
Every proton would have the energy of a baseball. It's bananas. Granted, space is really empty, but it's not that empty, somewhere around a hundred atoms per cubic meter. Your ship might look like a very, very long shooting star. Probably dialing the speed down a touch would be worth it for whatever your shielding material is, but who knows? We're talking miracle engines here. I think in the "Valkyrie" ship-on-a-stri…
> Every proton would have the energy of a baseball
I wonder if you could capture that energy and use it to generate thrust.
Most of the energy is coming from your thrust so it'd be a lossy process however if you're able to capture all of the energy then there won't be anything left to damage the ship.
Re: Relativistic Spaceship
#153Earlier quoted context omitted.
Could use such a ship as a time machine (well, that only goes one way).
Do you mean that someone in the space ship could, without extending their own lifespan beyond what is already expected, use the space ship to "travel" to Earth's distant future?
Kip Thorne said it's theoretically possible. One end of the wormhole is on earth, the other is on the spaceship. Then you fly the spaceship and hop into the wormhole and arrive into the future on Earth.
Re: Relativistic Spaceship
#154Earlier quoted context omitted.
Unless you could somehow make an Alcubierre warp drive. Of course…even if that was possible, it’s conjectured that the colonists already at your destination won’t appreciate you boiling the atmosphere when you hit them with blue shifted radiation. https://www.universetoday.com/93882/warp-drives-may-come-wit...
> it’s conjectured that the colonists already at your destination won’t appreciate you boiling the atmosphere when you hit them with blue shifted radiation. There's a general principle known as Jon's Law (not sure where the name comes from) that any powerful space drive is by definition a weapon of mass destruction. You see this in The Expanse when incredibly powerful fusion torchship rockets (a major part of the Exp…
in niven's "known space" universe that was known as the "kzinti lesson"; the kzinti
were a warlike race that thought humanity would be easy pickings because their telepathic spies said they had a civilisation completely at peace. turns out humanity figured out really fast that their mining lasers, fusion drives, etc could be used as weapons when the hostiles showed up.
Re: Relativistic Spaceship
#155Earlier quoted context omitted.
In the book series The Expanse, that was pretty much the only unrealistic technology that the humans had, which allowed them to colonize the solar system. Sure, there was some might-as-well-be-magic alien stuff later in the book, but by page 1, humans have colonized the solar system, purely with a hand-wavy engine that can generate sustained thrust without needing tons of reaction mass and without turning your exhaus…
Eh, there is a ton of unrealistic technology in book 1, the stealth ship for instance is impossible. By the authors own words they don't think of the books as being Hard Sci-Fi, harder then Star Trek sure.
What makes you think the stealth ship is impossible? They explain the concept pretty well in the first book: extensive cooling systems to soak up waste heat, large liquid tanks to store that heat internally for a while, and radar-absorbing coatings. We literally have all of those pieces today, it’d just cost unfathomable amounts of money to build with our current technology.
As a bonus, they even talk about the radar-absorbing coating not being perfect, and being able to detect the stealth ship as an object a few Kelvin above the background radiation when they pumped their radar into it.
Re: Relativistic Spaceship
#156So much of my life has been reading sci-fi that was perhaps before my time, but oddly prescient, and I think in some ways, self-deterministic.
I know (enough) about the math and physics, the energy required, etc. to logically understand how "impossible" it might be.
My brain still rebels and to some extent, wants to believe.
Re: Relativistic Spaceship
#157Earlier quoted context omitted.
Unless you could somehow make an Alcubierre warp drive. Of course…even if that was possible, it’s conjectured that the colonists already at your destination won’t appreciate you boiling the atmosphere when you hit them with blue shifted radiation. https://www.universetoday.com/93882/warp-drives-may-come-wit...
> it’s conjectured that the colonists already at your destination won’t appreciate you boiling the atmosphere when you hit them with blue shifted radiation. There's a general principle known as Jon's Law (not sure where the name comes from) that any powerful space drive is by definition a weapon of mass destruction. You see this in The Expanse when incredibly powerful fusion torchship rockets (a major part of the Exp…
> There's a general principle known as Jon's Law (not sure where the name comes from) that any powerful space drive is by definition a weapon of mass destruction.
Also known as the Kzinti Lesson, from Larry Niven's Known Space series. I've not read where in that series this term is first introduced, but they're somewhere in all that.
> Obviously anything even wilder like an Alcubierre Drive would be likewise
Not yet known; the original Alcubierre Drive is a toy model that demonstrates the point, but has so many problems with it that, as is, it definitely won't work.
Something else along similar lines that does work? The only thing it won't act like when it hits something, is like being hit by normal matter that's actually moving at the speed of light, because if it did it would also be an infinite free energy source.
Re: Relativistic Spaceship
#158Earlier quoted context omitted.
What if you define the "important" reference frame as the speed of light's (in the same direction you are going). Since c is universally constant, it seems like a reasonable privileged reference.
Doesn't really work this way. A lot of the wonkiness in SR is tied to the fact that the speed of light is the same, measured in _any_ reference frame. So, say you're on earth and you measure the speed of light... you find that it's c (~3x10^8 m/s). Now you get on a spaceship and accelerate to 0.5c with respect to earth, and you measure the speed of light relative to your spaceship... still c! In this way, you can't r…
So depending on how you measure, you’re always stationary or moving near light speed, or somewhere in between, depending on your measurement reference (the thing you’re moving relative to)?
How is there a speed limit at all, if that’s the case? You can accelerate to 0.5c and then toss an apple out the window and say you’re moving at the speed of an apple tossed out of the window, relative to the apple. You have all of c available as headroom again? You can accelerate up to 0.5c again, relative to the apple you tossed out the window?
I am imagining you will say that it will seem like this is what is happening to folks in the spaceship, but what’s really happening is that time is slowing for the spaceship and it’s passengers, and that they still can’t reach c. Fine. But c relative to what? There is no absolute c because there are no truly fixed points, so c relative to what?
Re: Relativistic Spaceship
#159Great visualization of the unintuitive nature of special relativity. It's kind of mind blowing to realize that if we could accelerate our spaceship at a mere 1G continuously, we could visit the center of the Milky Way in under 20 years (spaceship time), totally do-able in a human lifespan. Of course 27900 years would have passed on Earth, so you wouldn't be able to tell anyone about your vacation.
I suppose you would also have to worry about surviving the trip - every atom in the interstellar medium would damage your ship, likely penetrating the entire way through, and electromagnetic repulsion would only work with charged particles.
Or stopping. It takes the same amount of time to slow down as it did to speed up. Presumably, you'd have to rotate 180° so you are now thrusting in the opposite direction. So at the speeds you've reached to get there in 20 years (ship time), you'd just race on by.
Re: Relativistic Spaceship
#160Earlier quoted context omitted.
Less complicated. The rocket exhaust literally forms a plasma shield in front of the decelerating rocket.
Well then, it's easy: Just always face the exhaust in that direction! It's not rocket science!
> always face the exhaust in that direction! It's not rocket science!
You don't see a problem with trying to accelerate with two exhaust streams at 180º to each other?