9 ms·

Just out of curiosity, what's the reason for looking so far out? Are we assuming by the time we would actually need to visit these planets, we've discovered som

by smaili 9y ago

Just out of curiosity, what's the reason for looking so far out? Are we assuming by the time we would actually need to visit these planets, we've discovered some method to go faster than the speed of light? I only ask because realistically, how do we expect to actually make use of these resources if it would take so long just to reach it?

Maybestring 9y ago
Ease of travel is pretty unimportant for prioritizing research targets. No one is leaving for another star anytime soon.
- flukus 9y ago
  What about the other way around? It let's us know where we can expect visitors from.
  - Maybestring 9y ago
    What could you possibly resolve that would make you expect that?
indescions_2018 9y ago
I believe the end goal is some proof of extraterrestrial life. As sensing becomes more accurate, we may be able to detect certain biochemical signatures. Even of a hypothetical alien variety. At even great distances. Its an answer to the age old existential dilemma: are we alone in the cosmos. And would indeed provide a modicum of hope for the future of humanity ;) Exoplanet hunters rethink search for alien life https://www.nature.com/news/exoplanet-hunters-rethink-search-for-alien-life-1.23023 https://www.nature.com/news/exoplanet-hunters-rethink-search...
cryptoz 9y ago
700 LY is actually very close in! Some of these discovered exoplanets are 20,000 LY away. 700 LY is practically our backyard and makes it much easier to observe.
elihu 9y ago
Learning about far-away planets is useful if we want to know more about planets in general, such as how do they form and what kinds of planetary systems are we most likely to find outside our solar system? Even if we never visit that particular planet, we may learn something useful that tells us something about planets nearby, or even about our own solar system. At this point, we're just collecting data about extra-solar planets, which we weren't sure even existed until recently. With so many unknowns, it's exciting whenever we can fill in our knowledge gaps just a little bit.
TangoTrotFox 9y ago
The speed of light is not a speed limit on effective travel, but on observation. Imagine you build an engine that gives enough thrust to roughly produce an extra effective 1km/s of velocity each time you operate it. Even though the speed of light is 300km/s, that engine is going to operate exactly the same on the 301st operation as it did on the first operation. And, in fact, in 'real' terms if we create an engine capable of generating 1g of thrust for years at a time - we could travel 700 light years in ~12 years by thrusting for 1g forward 6 years, turning around and then thrusting for 6 years backwards. But of course the 'catch' is that time dilation (and length contraction) kick in. And so while from the frame of reference of the ship and all its travelers only 12 years will have passed, from the frame of reference of everybody back on Earth - 700 years would have passed. What we would observe is that as the ship approached the speed of light, its apparent mass would approach infinity, reaching a velocity asymptote at the speed of light. And these values are also not linear. It's possible to travel a practically unlimited distance in the span of a single human lifetime - from the perspective of that human. 100 trillion light years would take about 62 years at 1g from the perspective of those on board our ship. There's also really really fun paradoxes available here. Imagine somebody leaves Earth towards this planet and at some point decades, or perhaps even centuries later, we develop technology that enables substantially faster travel. Our planetary settlers on their 12 year journey could arrive 12 years later to find that not only is the planet indeed colonized, but it's colonized by the descendents of Earthlings that left decades, or even centuries, after they did. The really exciting thing here is that NASA seems to have gone silent on the EM drive after having it pass every single test they threw at it. In my opinion, this is evidence of classification which is something that would make sense. If the EM drive somehow actually works - and everything we know says it most certainly should not - that would change absolutely everything. The ability to actually start realistically considering these sort of missions would be mundane compared to other possibilities, which I'm not even going to get into as they sound, and should be, absurd. As an aside, this part on the EM drive is 100% speculation - not to be confused with everything stated above, which are direct and heavily tested (even if absurd sounding) consequences of relativity.
- tachyoff 9y ago
  > The speed of light is not a speed limit on effective travel, but on observation. It is absolutely a limit on effective travel (if we ignore things like wormholes for a second). Conventional motion through space is bounded by c for several reasons, not the least of which being that the closer you get to c, the more energy it takes to make smaller and smaller changes in velocity (the object acts as though it's gaining mass the faster it goes). In fact, it's asymptotic. Accelerating a particle to c would require an infinite amount of energy.

by smaili 9y ago

Maybestring 9y ago

Ease of travel is pretty unimportant for prioritizing research targets. No one is leaving for another star anytime soon.

flukus 9y ago
What about the other way around? It let's us know where we can expect visitors from.
- Maybestring 9y ago
  What could you possibly resolve that would make you expect that?

indescions_2018 9y ago

I believe the end goal is some proof of extraterrestrial life. As sensing becomes more accurate, we may be able to detect certain biochemical signatures. Even of a hypothetical alien variety. At even great distances. Its an answer to the age old existential dilemma: are we alone in the cosmos. And would indeed provide a modicum of hope for the future of humanity ;) Exoplanet hunters rethink search for alien life https://www.nature.com/news/exoplanet-hunters-rethink-search-for-alien-life-1.23023 https://www.nature.com/news/exoplanet-hunters-rethink-search...

cryptoz 9y ago

700 LY is actually very close in! Some of these discovered exoplanets are 20,000 LY away. 700 LY is practically our backyard and makes it much easier to observe.

elihu 9y ago

Learning about far-away planets is useful if we want to know more about planets in general, such as how do they form and what kinds of planetary systems are we most likely to find outside our solar system? Even if we never visit that particular planet, we may learn something useful that tells us something about planets nearby, or even about our own solar system. At this point, we're just collecting data about extra-solar planets, which we weren't sure even existed until recently. With so many unknowns, it's exciting whenever we can fill in our knowledge gaps just a little bit.

TangoTrotFox 9y ago

The speed of light is not a speed limit on effective travel, but on observation. Imagine you build an engine that gives enough thrust to roughly produce an extra effective 1km/s of velocity each time you operate it. Even though the speed of light is 300km/s, that engine is going to operate exactly the same on the 301st operation as it did on the first operation. And, in fact, in 'real' terms if we create an engine capable of generating 1g of thrust for years at a time - we could travel 700 light years in ~12 years by thrusting for 1g forward 6 years, turning around and then thrusting for 6 years backwards. But of course the 'catch' is that time dilation (and length contraction) kick in. And so while from the frame of reference of the ship and all its travelers only 12 years will have passed, from the frame of reference of everybody back on Earth - 700 years would have passed. What we would observe is that as the ship approached the speed of light, its apparent mass would approach infinity, reaching a velocity asymptote at the speed of light. And these values are also not linear. It's possible to travel a practically unlimited distance in the span of a single human lifetime - from the perspective of that human. 100 trillion light years would take about 62 years at 1g from the perspective of those on board our ship. There's also really really fun paradoxes available here. Imagine somebody leaves Earth towards this planet and at some point decades, or perhaps even centuries later, we develop technology that enables substantially faster travel. Our planetary settlers on their 12 year journey could arrive 12 years later to find that not only is the planet indeed colonized, but it's colonized by the descendents of Earthlings that left decades, or even centuries, after they did. The really exciting thing here is that NASA seems to have gone silent on the EM drive after having it pass every single test they threw at it. In my opinion, this is evidence of classification which is something that would make sense. If the EM drive somehow actually works - and everything we know says it most certainly should not - that would change absolutely everything. The ability to actually start realistically considering these sort of missions would be mundane compared to other possibilities, which I'm not even going to get into as they sound, and should be, absurd. As an aside, this part on the EM drive is 100% speculation - not to be confused with everything stated above, which are direct and heavily tested (even if absurd sounding) consequences of relativity.

tachyoff 9y ago
> The speed of light is not a speed limit on effective travel, but on observation. It is absolutely a limit on effective travel (if we ignore things like wormholes for a second). Conventional motion through space is bounded by c for several reasons, not the least of which being that the closer you get to c, the more energy it takes to make smaller and smaller changes in velocity (the object acts as though it's gaining mass the faster it goes). In fact, it's asymptotic. Accelerating a particle to c would require an infinite amount of energy.