I:was really confused for a second, until I realized they must mean Bussard ramjets, because standard ramjets are very much in use and lived up to the hype. It’s a good article, although I still disagree with some of it. In particular...
NAFAL trips mean crossing time as well as space. But that shouldn’t prevent exploration; anyone who would consider racing off that far into the future probably wouldn’t have friends and relatives about whom they deeply cared in any case.
Maybe, but subjectively a few years into your journey when tens of thousands of years have passed on Earth, and you’ve been totally forgotten, your technology is equivalent to rocks banging together, maybe you’d care? When you arrive in a subjective 30+ years and millions of years passed on Earth and people aren’t even remotely human anymore, and you’re a relic of a relic its going to be weird. Who are you exploring for exactly? Not humanity, they moved in without you, so unless it’s purely about starting a colony it’s a pointless exercise.
Even more galling would be the result you’d encounter if FTL turns out to be viable, unlikely as that seems today. You arrive in Andromeda only to discover that human colonized it a million+ years before your arrival. Whoops. Relativity is a stone cold bitch.
I like how Pandora's Star starts... Humanity finally arrives on Mars, with much grandeur, to find a dude standing there connected to an air hose that leads through a wormhole to a lab in California.
I'd just like to add how terrific Pandora's Star and Judas Unchained are! And the following Void Trilogy was pretty good as well, though the latter two books got little weird.
I love them as well, but everything in the void feels more like fantasy to me and I always start yearning for the parts in normal space. I didn't finish the latest books (The Chronicle of the Fallers). I just want quantum mind uploading post physical planet scourging space ship battles. Not that telekinesis stuff.
On the site the article links to at the end, it talks about this "jumping the gun" problem.
The Wait Calculation allows future space explorers to avoid the "jumping the gun" problem (and also avoid being paralyzed with indecision by terror of jumping the gun). The equation shows that, assuming technology develops in such a way that there is exponential growth in the velocity of travel, there is an optimal departure time for arriving earliest. Kennedy states that the equation applies even if somebody invents faster-than-light travel.
Really? That sounds straight up awesome to me. After a few years of shore leave, I'd be tempted to grab one of the most reliable FTL ships, pack myself full on longevity treatments and then turn around and go again. See what humanity is like in another few million years. If it all goes to shit at least I'll have an FTL ship with me to go wandering around with.
All things considered, this might be a really good way of securing the existence of the human race, too. Send out one or two of these per millenia, as high speed stasis pods to refound humanity if it all goes horribly wrong in the mean time.
Alastair Reynolds' House of Suns tells a similar story. A family of 1,000 clones split up to tour the galaxy and reunite every 200,000 years. Since they live lone, solitary lives off the grid, they witness from afar many civilizations rising and dying. I found it much more interesting than Reynolds' bone-dry Revelation Space series.
If interested in the concept, V. Vinge's Across Realtime books, mainly Maroneed in Realtime explores this concept. Humanity invents stasis bubbles (time stands still inside or almost still), and you can bubble yourself, ships, towns etc for any amount of years. Essentially you can time travel but only forward.
Marooned in Realtime has multiple groups of people travelling into the future, all having set out before a mysterious event that wiped out the rest oh humanity. They experience the evolution of the Earth, but the only human civilisation they experience is that of their fellow travelers. 'The Forever War' (referenced elsewhere here) in contrast has individuals who dip into evolving human civilisation, finding massive societal changes each time they return, so much so that 'home' becomes the time jumping army they belong to.
I would like to recommend Peter Watts' "The Freeze-Frame Revolution", and its related short stories on his blog. It deals with a very, very long term project at relativistic speeds.
> At around .998 c, the impacting ravioli begins to behave less like ravioli and more like an extremely intense radiation beam. Protons in the water of the ravioli begin to successfully penetrate the nuclei of the hull metal. Thermonuclear interactions, such as hydrogen fusion, may take place in the tomato sauce.
Projectrho is an amazing treasure trove for aspiring scifi writers, wild dreamers etc. Just never forget that the sources are mostly scifi stories and usenet discussions. A lot of the math that is presented as realistic is actually not at all grounded in reality.
> There is an alternative to the Bussard ramjet that offers many of its advantages (at least as far the needs of science fiction authors go)—one that has inexplicably only been used by a single author to my knowledge. What that alternative is, however, will have to wait for another essay.
They show up in some recent Alastair Reynolds novels (House of Suns and the Revelation Space stuff, at least), though mostly as a bit of a dead end technology which doesn’t go as fast as people might have liked.
Pity they’re not workable, really, they were a fun idea.
I think they're still full of great potential in a slightly evolved form. You can get a ton of acceleration out of the interstellar medium, so long as it's deceleration, and you're not trying to extract all of your energy from random protons in interstellar space.
Quickly accelerate a craft up to 0.1C with beamed propulsion, then have it decelerate at the end of its trip with magsails.
In at least one of his stories the conjoiner engines were similar to highly advanced ramscoops, but he seems to have discarded the scoop part in later novels.
Yeah; in the novels they just work by magic (even in-universe, more or less). There is a ramscoop in The Prefect, though; it suffers from the practical issues mentioned in the article and is not considered useful.
The article mentions Larry Niven’s A Gift From Earth, but in fact Bussard Ramjets are tightly integrated into several of the stories in Niven's Known Space [0] sequence. Briefly, humanity sends colonists to several nearby stars in manned Bussard Ramjet ships. Eventually, humans encounter aliens who sell them the secret of an FTL drive, and the ramjet ships become obsolete. Several plot-points in the Known Space stories relate to the quirks of the planets colonised by the Ramjet crews, and in one short story (The Ethics of Madness), a significant part of the plot is a chase across spacetime of two men in separate Ramjet ships
It's interesting to see this topic brought up without a reference to Haldeman's seminal Forever War. I can't recall whether he specifically outlines the means of interstellar travel in his universe as Ramjets but the story heavily relies on this concept.
Haldeman doesn't use Ramjets in 'Forever War'[0], since the soldiers have access to Collapsars (black holes?) for instantaneous point-to-point jumps. He doesn't describe the drive technology that gets them from between planets and the collapsars, except to say that the ships were 'converted cattlewagons ... with extra reaction mass'
Yeah I couldn't recall whether he specifically called out the drive technology used to accelerate and decelerate from the collapsars or not. From the description and mechanics it sounded pretty similar.
IIRC they use "collapsars", which are wormhole-like things that are discovered, not made (or maybe left there by a previous civilization?). They spend weeks and months accelerating to and decelerating from collapsars, but I don't think they mention ramjets as a means to accelerate and decelerate in "normal space".
Probably very few. NORMAL ramjets (ie not magic space fusion ones) are quite old; the first ramjet aircraft was tested by the Soviets in 1940, and the US tested ramjet missiles in the late 40s. And scramjets (supersonic ramjets, where the internal airflow is supersonic) were meant to be the next big thing since the 50s, though they’ve never really worked out.
Interesting! That must be the source of the matter for the matter/antimatter reaction. I started digging deeper into the Memory Alpha wiki but couldn't confirm it.
NAFAL trips mean crossing time as well as space. But that shouldn’t prevent exploration; anyone who would consider racing off that far into the future probably wouldn’t have friends and relatives about whom they deeply cared in any case.
Maybe, but subjectively a few years into your journey when tens of thousands of years have passed on Earth, and you’ve been totally forgotten, your technology is equivalent to rocks banging together, maybe you’d care? When you arrive in a subjective 30+ years and millions of years passed on Earth and people aren’t even remotely human anymore, and you’re a relic of a relic its going to be weird. Who are you exploring for exactly? Not humanity, they moved in without you, so unless it’s purely about starting a colony it’s a pointless exercise.
Even more galling would be the result you’d encounter if FTL turns out to be viable, unlikely as that seems today. You arrive in Andromeda only to discover that human colonized it a million+ years before your arrival. Whoops. Relativity is a stone cold bitch.