Just so you know, faster-than-light travel is not necessary to explore the stars. With enough constant acceleration (which seems to be achievable with the tech that these craft have demonstrated) you could go pretty much anywhere in the galaxy in your lifetime. The obvious downside is that the further you go, the more time-dilation becomes an issue for everyone else. For example, you may travel ~9 light years to Sirius in a matter of months from your perspective, but 10 years pass for everyone else. Still, if your goal is to explore, I find this to be quite a decent trade-off, and given that we are already making strides in life-extension that time may become a non-issue very quickly.
You have massively misunderstood physics if you think that people could travel faster than light and cross a galaxy in a single lifetime
in a single lifetime
There’s some wiggle-room there. A species that is naturally biologically immortal (or had biology that supported long periods of inactivity) might not find that spending hundreds of years to travel to a nearby star system was a deal-breaker for interstellar travel. They might be more motivated to execute such a project than we are since they could not just wait for their ancestors to die of old age as a way for younger members of the species to have control.
Also there is a possibility that a species might develop the technology to create a partly or fully artificial version of themselves that makes long interstellar trips less of an obstacle (synthetic biology, a combination of biology and machine, pure machine, etc).
Natural humans are certainly poorly suited for interstellar travel, but it may be that other kinds of life are more tolerant of it, or have redesigned some members of their species to handle it.
I don’t want to be rude but this isn’t correct as far as my understanding. I’m no expert, so I’m not confident in my ability to describe exactly how… But the phrase “you may travel ~9 light years to Sirius in a matter of months from your perspective, but 10 years pass for everyone else.” I don’t think that is correct exactly.
Again not trying to be rude and I am very happy to be corrected but I want to understand it.
The time dilation effect is pretty well known and comes naturally from the equations of the General Relativity Theory.
It’s also been proven experimentally in particle accelerators (like CERN) when particles with at rest very short and well known half-lives (i.e. they natural break down into other particles some time after being created) lasted a lot longer (from our point of view) when travelling at near light speed.
However that effect only really starts getting noticeable without special equipment when the speed something is travelling at is getting near the speed of light (something like 90% or more of light speed).
This works correctly for the example of the previous poster because the distance to Sirius is given in light-years, which is literally the number of years that takes light (which by definition travels at the speed of light) to travel that distance.
(By the way, from the same equations from were you get time dilation comes that from the point of view light the trip is instantaneous)
So yeah, travelling a distance of that takes light 9 years to travel would be theoretically possible to do so fast (near light speed) that it would seem for those doing the trip to only take a few months (even though for those outside it would still seem to take longer than 9 years - as it takes light 9 years to get there so something at sublight speeds would take longer than the 9 years that takes for light).
Yeah, this is highly counter intutive so it “feels” wrong. If fact, the whole General Theory Of Relativity is highly counter intuitive. Yet, quite independently of what intuition (which is just a destilation of our personal experience) tells us, all that we’ve been able to observe so far in applicable situations is things happenning as predicted by that theory, not “intuition”.
I’ll put it another way then: any information you intended to send back after you arrive in Sirius would take ~9 years to arrive back home. Due to causality, this means that you cannot interact with Earth in any way for – at minimum – 9 years. However, from your perspective, you accelerated at let’s say 10 Gs (speed increased by 98 meters per second every second), until you were half-way to Sirius, which will take about 5 months. Then you decelerated at -10 Gs to arrive with 0 speed, another 5 months. You perceive only 10 months of travel, but you are now 9 light-years from home.
The math is not the part which is difficult, and requires only a basic understanding of relativistic physics. The issue is maintaining 10 Gs of constant acceleration for 10 months.
Yeesh I’m just not good at that kind of stuff. Time dialation is what is making this hard for me to wrap my head around, but basically the big issue with this method of travel is you need infinite energy (which might be something these ships somehow do) and its like fast forwarding into the future, so even if you go back immediately it will be like you were gone ~18 years but only experience less than 2.
It is certainly an interesting thing to think about, but sounds depressing in practice. If this is the practical way that some beings have traveled here, I feel like we are missing a piece of the puzzle for long distance space travel. Maybe they have a way to do something about time dilation. Or maybe they just don’t ever die…
