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You know what else is an obstacle to relativistic spaceflight? Being able to do relativistic space flight. Fun fact: people realized this a long time ago, and proposed different "shields" in front of the ship (it turns out that the most effective shape is a smoothed-out cone [of ice, say] -- see Asimov's Song of a Distant Earth).
That's okay, there's time to work on the shielding. 0.03 c is the most that can be feasibly achieved using top-end near future technology like dusty plasma fission fragment rockets. https://en.wikipedia.org/wiki/Fission-fragment_rocket
Thermonuclear pulse propulsion (a la Project Orion) can do better than that- up to 0.1c. And that requires no unproven technology; just a lot of money and a lot of politics (and a lot of fission fuel to buy with that money; I dunno if it's more than you could actually get on the market or not, but it would definitely cost A Lot).
Earlier quoted context omitted.
'a few rouge hydrogen atoms' It's rogue. Sorry, pet hate, can't help myself. That and people typing 'tounge' when they mean tongue.
Unless the atoms were moving away from the observer, then they might appear a little rouged.
Earlier quoted context omitted.
Thermonuclear pulse propulsion (a la Project Orion) can do better than that- up to 0.1c. And that requires no unproven technology; just a lot of money and a lot of politics (and a lot of fission fuel to buy with that money; I dunno if it's more than you could actually get on the market or not, but it would definitely cost A Lot).
IIRC you're talking on the order of several hundred nuclear bombs for a single interstellar trip, i.e. a significant fraction of the current US warhead supply, but by no means the whole lot.
http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propul...
There's one thing I never quite got about these speculations. When you consider a ship leaving a solar system and accelerating, and the speed gained turning the "ambient hydrogen" into deadly radiation, why does it always seem to assume that hydrogen atoms are just kind of hanging out at low velocities relative to the home solar system and only turn into a problem when the bald captain says "engage"? Its a big univer…
Because the hydrogen atoms we care about are bound in galactic orbit, and that means they have a relatively low maximum relative velocity to us. If they weren't, they would all fly out into the intergalactic void in geologically short timescales, star formation would cease, and we'd have no such radiation problems after all.
There's also the risk of hitting small dust particles, etc. A quick back of the envelope calculation reveals that hitting a spec of dust that weighs just 1 ug (a millions of a gram) at 90% c produces ~36 mega joule. Not a huge amount of energy (about the energy of burning 1kg of coal), but still. Hitting a grain of sand (10mg) at 90% c produces ~360 giga joule (energy of a small lightning)
I think once we are advanced enough to figure out how to propel anything that fast or able to pack the needed energy, this part might be easy to solve. Remember per special relativity mass increases as we approach C. Also I think there will be other physiological problems while accelerating to C. It would take like 34 days at 10g acceleration to get to C. I wonder how our bodies would handle 34 days at that kind of g…
First, people on the ship will not feel as if they "have more mass". Their physical properties will be exactly identical, because they are at rest in their frame of reference. Flying through a galaxy at 0.999c is identical to "sitting still" while a galaxy flies by at 0.999c.
Second, you're ignoring relativistic effects in your calculation of the amount of time it takes to "reach c". You can't just divide light speed by the acceleration and convert to days. You need to include the effects of time and space dilation, in which case you'll find you have to pick a target less than c because no matter how long you accelerate you only approach c.
There's one thing I never quite got about these speculations. When you consider a ship leaving a solar system and accelerating, and the speed gained turning the "ambient hydrogen" into deadly radiation, why does it always seem to assume that hydrogen atoms are just kind of hanging out at low velocities relative to the home solar system and only turn into a problem when the bald captain says "engage"? Its a big univer…
In short, because the Milky Way disk sets a preferred rest frame. Other matter in the galaxy all rotates with approximately the same speed around the galactic center. Here are some numbers to give you intuition. Tangential speed of the galactic disk, obtained by averaging over nearby stars: ~ 250 km/s Speed of sun (and other nearby stars, in random directions) with respect to the galactic disk: ~ 15 km/s Speed of Ear…
I can't help thinking that statements like these are merely meant to bog us down. I've heard and read statements like 'Interstellar travel isn't possible.' or my favourite 'We've enough problems down here on Earth already so let's forget about the more visionary ones altogether.' since the eighties. I mean, why does one become a scientist if one doesn't at least have some greater vision? This kind of statement seems…
I only read the abstract, but I don't think the article is nearly as prohibitive as your statements. It says that diverting the radioactive hydrogen is a "daunting problem" i.e. hard but not impossible. Even if Near-C space travel _is_ invariably fatal, that's not so broad as "interstellar travel isn't possible". There's still wormholes and hyperspace and whatever exotic ideas we might come up with in the future.