In what year do you think humans will colonize the first planet outside of Earth?

[Incal]

Never. Once Europe and the anglosphere have been overpopulated by browners, the world will revert to the middle ages: we'll be lucky if someone still knows how to read in the next 50 years.

I have to correct myself: my answer was too eurocentric. China could colonize other planets: they don't have brown minorities and the only problematic brown-wannabe they have has been kept in line.

There were even a series of novels speculating about his:

[Insuperable]

I didn't mention Europa (another Jupiter's moon), because there can be too much radiation in there. Out of the Jovian satellites, the closer to Jupiter, the more radiation you get from the Jupiter radiation belt. And Io (closer to Jupiter than Europe) is even much worse.

Regarding interstellar travel, the distances are too huge. Even the closest known exoplanets (Proxima Centauri B, and its companion Proxima C), which are like 4 light years away, are still unreachable with the current technology. Even if 4 light years might sound like relatively close for astronomical standards, is still such a huge distance that at the speed of several kilometers per second of the Voyager space proves (which is the fastest thing that humans have ever built) they would still last tens of thousands of years to travel that distance.

The only two options are multi generational travels or travel at a decent fraction of light speed. In the scenario of multi generational travels, assuming that they travel at a conventional speed (lets say, like the Voyager probes,or a bit faster) all the human beings that stay on earth won't obviously be alive that long as to witness even when they reach the closest planetary system (and let alone other farther away planetary systems), since they would take multiple generations to get there. No to mention that it would take many decades to build such a spacecraft capable of traveling those huge interstellar distances, even if they were to travel at "conventional" speeds.

And the second scenario of building some spacecraft that travels to lets say half the speed of light, or lets say 25% the speed of light, even if they would theoretically reach the stars within a reasonably scale of the human life scale (including those on earth), it has its serious challenges: firstly that's a technological challenge that we don't know how long it would take to develop, maybe many decades or even centuries, and secondly, there are serious doubts of how practicable it would be to accomplish that goal. Once I read that one of the big challenges of traveling at speeds close to the speed of light (even if it's only, lets say 25% the speed of light) is that the interstellar void is not that empty as it seems to be, but has some scattered atoms, that despite their "relatively low concentration" at those huge speeds we are talking about, they would become a lethal danger for the hypothetical crew members, since the spacecraft would drive at those huge speeds against those scattered atoms, that at those huge speeds they wouldn't be felt by the spacecraft and its crew like being scattered any more, since they would impact millions of them in matter of seconds, creating a lethal ionizing radiation effect on the spacecraft and their crew members.That without mentioning the cosmic rays, and other dangers and the interstellar dust that would also erosion the spacecraft at those huge speeds. It would be a very big challenge to figure out how to travel at those speeds without being killed by such lethal radiation, and even the spacecraft getting disintegrated.

Imagine going 50% the speed of light and suddenly propulsion stop working. You'd end up as smear on a wall. Of course in Star Trek they solve this using some form of inertial damper drive which also enables them to walk normally even when ship accelerates or deaccelerates, goes up and down etc. It's a bigger science fiction device than WARP engine is.

[Annihilus]

Imagine going 50% the speed of light and suddenly propulsion stop working. You'd end up as smear on a wall. Of course in Star Trek they solve this using some form of inertial damper drive which also enables them to walk normally even when ship accelerates or deaccelerates, goes up and down etc. It's a bigger science fiction device than WARP engine is.

Nothing would happen and you would keep going at 50% of the speed of light, or do you mean you crash into something?

You can travel all distances in the universe within a lifetime if you get close to the speed of light. Say 5 years accelerating at 1g would net you 99.99% of the speed of light. Bonus, you'll have perfect 1g gravity aboard the ship (and when you flip the ship and brake). Problem, time slows for you so by the time you reach your destination tremendous amounts of time will have passed on earth.

[Brás Garcia de Mascarenhas]

Unfortunately it probably won't be in my lifetime, but it would be something interesting to see.

[alnortedelsur]

Imagine going 50% the speed of light and suddenly propulsion stop working. You'd end up as smear on a wall. Of course in Star Trek they solve this using some form of inertial damper drive which also enables them to walk normally even when ship accelerates or deaccelerates, goes up and down etc. It's a bigger science fiction device than WARP engine is.

hmmm... that's unlikely. The spacecraft would continue going at that speed by inertia. But as the user Annihilus said, they should manage to gradually reduce the speed as they approach to the planetary system of their destination.

In any case, the challenges I mention would still be the big issue when it comes to traveling at those speeds.

I was checking some sources, and it seems that the most they could manage to approach to the speed of light without facing those lethal ionizing radiation effects would be to travel at like 10% of the speed of light at most. That would be a lifetime for those on earth, since only to get to the Alpha Centauri planetary system would take around 40 years, and actually it would take more than that, because we have to take into account the acceleration until reaching that speed, and then the deceleration. However, people in the spacecraft would feel it like less time. At 10% the speed of light the difference in the passage of time between those traveling in the spacecraft and people on earth wouldn't be that much as that at light speed, but would be still considerable.

[Insuperable]

Unfortunately it probably won't be in my lifetime, but it would be something interesting to see.

hmmm... that's unlikely. The spacecraft would continue going at that speed by inertia. But as the user Annihilus said, they should manage to gradually reduce the speed as they approach to the planetary system of their destination.

In any case, the challenges I mention would still be the big issue when it comes to traveling at those speeds.

I was checking some sources, and it seems that the most they could manage to approach to the speed of light without facing those lethal ionizing radiation effects would be to travel at like 10% of the speed of light at most. That would be a lifetime for those on earth, since only to get to the Alpha Centauri planetary system would take around 40 years, and actually it would take more than that, because we have to take into account the acceleration until reaching that speed, and then the deceleration. However, people in the spacecraft would feel it like less time. At 10% the speed of light the difference in the passage of time between those traveling in the spacecraft and people on earth wouldn't be that much as that at light speed, but would be still considerable.

True. I had a moment of stupidity. There is almost no drag in vacuum. You can basically reach 0.1c, shut engines off and just cruise long distances.

[BakersfieldChimp]

Electronics and some other fields of technology developed rapidly. OTOH space technology is still in the 60s or 70s. Following this pace we'll colonize moon in several centuries from now or never.

Keep this in mind, the Wright Brother's first flight was in 1903. We made it to the moon in 1969. That is an amazing amount of space progress for 66 years. Mankind can accomplish astonishing things when we set our minds to it.

[Ruggery]

Keep this in mind, the Wright Brother's first flight was in 1903. We made it to the moon in 1969. That is an amazing amount of space progress for 66 years. Mankind can accomplish astonishing things when we set our minds to it.

Look, for example, between Columbus's first voyage to America and a person's first circumnavigation of the world by ship, almost 40 years passed. However, building a ship is much easier than a spaceship. In addition to the calculations, if humanity puts its mind to it, we will be able to advance in record time.

[Insuperable]

Keep this in mind, the Wright Brother's first flight was in 1903. We made it to the moon in 1969. That is an amazing amount of space progress for 66 years. Mankind can accomplish astonishing things when we set our minds to it.

Energy and power sources are a big problem for space travel. Not only is it a big problem for space travel, but it's also a big problem for life on Earth. No known interstellar propulsion will help man colonize anything outside Earth. Maybe some antimatter quantum mumbo jumbo drive might help or some exotic astrophysics ideas.

Maybe leaps in interstellar space travel happen in every 100 or even 200 years or so compared to say electronics which happen almost continuously.

[BakersfieldChimp]

Energy and power sources are a big problem for space travel. Not only is it a big problem for space travel, but it's also a big problem for life on Earth. No known interstellar propulsion will help man colonize anything outside Earth. Maybe some antimatter quantum mumbo jumbo drive might help or some exotic astrophysics ideas.

Maybe leaps in interstellar space travel happen in every 100 or even 200 years or so compared to say electronics which happen almost continuously.

Did you know, that in the late nineteenth century, Lord Kelvin(they named a tempeture scale after him) "proved" that man would never fly? He lived long enough for the Wright brothers to show he was mistaken. Kelvin's mistake was he focused on the conventional methods known at the time and forgot that there could be a discovery of a different method. Kelvin made his declaration in 1895. When car races were at 15mph (24kph). The physics of aerodynamics wasn't on anyone's radar.


The main reason mankind has shied away from manned space travel outside of our moon system has been the added burden of keeping humans alive. The problems of sustaining life in a space capsule have been listed. It is much cheaper and easier to send a probe that sends back data.

I'm not saying interplanetary travel will happen any time soon. I'm just saying when or if we need to go, we will figure out a way. It will undoubtedly utilize technology that none of us can even conceive of today.