4 ms·

Meh, given the hype for this press-release, I was hoping for something more extraordinary frankly. Not that finding other exoplanets isn't amazing, just that we

by sktrdie 11y ago

Meh, given the hype for this press-release, I was hoping for something more extraordinary frankly. Not that finding other exoplanets isn't amazing, just that we're all waiting to find out whether we are alone or not in the universe. Finding out that other advanced civilizations exist out there would bring such an amazing new meaning to life. If I could ask for one wish, it would be to find out if we're alone or not. Somehow knowing we're alone would be a large one to swallow, but the universe works in ways that it doesn't care about our feelings.

uptown 11y ago
Read: "Where are all the aliens?" http://qz.com/452452/where-are-all-the-aliens/ http://qz.com/452452/where-are-all-the-aliens/ "We’re rare, we’re first, or we’re fucked."
- camikazeg 11y ago
  Can't interstellar travel just be impossible?
  - Jweb_Guru 11y ago
    Or at least, highly energy-intensive and fragile (due to problems like cosmic radiation) to the point of impracticality, particularly when it comes to something like panspermia (or, for that matter, sending high-energy signals directly at a planet that doesn't detectably have life from the perspective of the originating species). This possibility is not weighted nearly highly enough in most analyses.
    - TheOtherHobbes 11y ago
      Interstellar travel is perfectly possible if you're not in a hurry. Assuming there's no way to sidestep GR, the real problem is the human lifespan (and attention span.) If our culture moved at 0.1% of the current rate and we lived a thousand times as long, a 1400 year round trip wouldn't be problematic. It's possible to imagine low-energy lifeforms that move that slowly. But they wouldn't be looking for Earth-like planets to colonise - they'd be looking for much colder and more stable locations. And we wouldn't be looking for the right spectroscopic signals to give them away, because we don't know what they are.
      - Jweb_Guru 11y ago
        The problem isn't just sending something (or someone) to another star (though it would take far longer than 1400 years with any currently plausible technology and energy expenditure). It's sending something accurately to another star (can't use too much energy adjusting course, since fractional additions to weight require tremendously more power) with a payload that's still operational by the time it gets there. Think about the myriad problems NASA probes have after just a relative handful of years or so in space. Also worth noting is that all deep space missions thus far have had to rely on nuclear power, usually using 238-Pu with a half life of less than 90 years. With such technology, a well-shielded, self-correcting computer system traveling at reasonable speeds and energies could not survive too long because it would simply run out of power. AFAIK, workarounds for this rely on exotic power sources and unproven physics--it's entirely possible that these don't pan out, and this provides our "Great Filter."
        stcredzero 11y ago
        There's been some nifty work done on the practicality of electrodynamic tethers and using them to turn a starship against the galactic magnetic field. You won't get sci-fi ship maneuverability out of this, but it's useful for course corrections without having to carry or expend reaction mass. As far as onboard power sources go, fission seems perfectly cromulent. You just have to protect those radiators.
        Jweb_Guru 11y ago
        I can only find one source on using tethers in interstellar travel: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050215611.pdf http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2005021.... To quote the article, for energy production: > Since the tether current is 1,333 amps, ne = 3 X 10‘‘ m-3 and the ship’s velocity is 900 km/sec, the effective electron-collector radius is approximately 3 13 km. This appears to have a toroidal-field ramscoop as a prerequisite. For thrustless turning, a 0.06 degree turn requires a tether 10^3 km long: > To obtain a six-degree trajectory modification during a 1,400-year journey with the tether current assumed, the tether length must be increased by a factor of lOOX to equal l0^5 km. This would increase tether mass to 2.7 X lo5 kg. And this is using a reference ship many scientists are skeptical about: > ...it is assumed here that the primary propulsion for these ships is the ultra-thin, space manufactured solar sail unfurled as close to the Sun as possible at the perihelion of a parabolic or hyperbolic solar orbit. After acceleration to interstellar cruise velocity, it is also assumed that sail and cables are wound around the habitat section to provide extra cosmic ray shielding. The sail is unfurled again for deceleration at the destination star.... since the baseline sailcraft for this analysis is somewhat faster, either more advanced sail/cable materials are required or the pre-perihelion orbit is hyperbolic. I'd definitely categorize that under "experimental power sources and unproven physics." Perhaps you are thinking of a different article?
  - GeneralMayhem 11y ago
    That would be a case of the "great filter" being in the future, no?
    - camikazeg 11y ago
      I've always read the "great filter" as some kind of mass extinction. I just think that the Fermi paradox gained popularity when everyone thought that both our travel speeds and our population would continue to grow exponentially, making space colonization both inevitable and necessary. What if we (and every other intelligent life) just level off when we start reaching the limits of physics and the available resources within our own solar system?
      - svachalek 11y ago
        I see it as a galactic cold war. On a galactic time scale, any civilization will reach a technology level of "maximum allowed by physics" relatively quickly, unless physics is indeed an infinite maze of rabbit holes. Therefore inter-species conflicts are resolved by mass/energy available. Any civilization that doesn't expand to interstellar levels of power is subject to the whims of those that do. If you can expand, you must.
- clem 11y ago
  Or, "We're deaf, blind, and isolated."
- jsmeaton 11y ago
  That was an incredible read. Thanks for sharing!
qrendel 11y ago
By some accounts we should probably be desperately hoping we are alone in the universe (at least with regards to technological civilizations), since it would mean the Great Filter is behind us rather than ahead. The alternative being we're very likely to go extinct before we get a chance to colonize the galaxy, and since that could probably be done using synthetic biology developed within the relatively near future, that would give our civilization an expected lifetime of less than a few hundred years at most. The more life that exists close to or surpassing our own level of development, the more bleak the future looks for our civilization.
DanAndersen 11y ago
I can understand the disappointment. It's helpful to always keep in mind that when it comes to discoveries, it's easy to hype ourselves up excessively. Recognize that the PR arms of scientific organizations and universities are also somewhat responsible. I find it helpful to remember that any Big Announcement like definite signs of life or advanced alien civilizations or asteroids hurtling toward Earth wouldn't be in such a small-scale announcement. You'd have the President appearing on TV or something.

by sktrdie 11y ago

uptown 11y ago

Read: "Where are all the aliens?" http://qz.com/452452/where-are-all-the-aliens/ http://qz.com/452452/where-are-all-the-aliens/ "We’re rare, we’re first, or we’re fucked."

camikazeg 11y ago
Can't interstellar travel just be impossible?
- Jweb_Guru 11y ago
  Or at least, highly energy-intensive and fragile (due to problems like cosmic radiation) to the point of impracticality, particularly when it comes to something like panspermia (or, for that matter, sending high-energy signals directly at a planet that doesn't detectably have life from the perspective of the originating species). This possibility is not weighted nearly highly enough in most analyses.
  - TheOtherHobbes 11y ago
    Interstellar travel is perfectly possible if you're not in a hurry. Assuming there's no way to sidestep GR, the real problem is the human lifespan (and attention span.) If our culture moved at 0.1% of the current rate and we lived a thousand times as long, a 1400 year round trip wouldn't be problematic. It's possible to imagine low-energy lifeforms that move that slowly. But they wouldn't be looking for Earth-like planets to colonise - they'd be looking for much colder and more stable locations. And we wouldn't be looking for the right spectroscopic signals to give them away, because we don't know what they are.
    - Jweb_Guru 11y ago
      The problem isn't just sending something (or someone) to another star (though it would take far longer than 1400 years with any currently plausible technology and energy expenditure). It's sending something accurately to another star (can't use too much energy adjusting course, since fractional additions to weight require tremendously more power) with a payload that's still operational by the time it gets there. Think about the myriad problems NASA probes have after just a relative handful of years or so in space. Also worth noting is that all deep space missions thus far have had to rely on nuclear power, usually using 238-Pu with a half life of less than 90 years. With such technology, a well-shielded, self-correcting computer system traveling at reasonable speeds and energies could not survive too long because it would simply run out of power. AFAIK, workarounds for this rely on exotic power sources and unproven physics--it's entirely possible that these don't pan out, and this provides our "Great Filter."
      - stcredzero 11y ago
        There's been some nifty work done on the practicality of electrodynamic tethers and using them to turn a starship against the galactic magnetic field. You won't get sci-fi ship maneuverability out of this, but it's useful for course corrections without having to carry or expend reaction mass. As far as onboard power sources go, fission seems perfectly cromulent. You just have to protect those radiators.
        Jweb_Guru 11y ago
        I can only find one source on using tethers in interstellar travel: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050215611.pdf http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2005021.... To quote the article, for energy production: > Since the tether current is 1,333 amps, ne = 3 X 10‘‘ m-3 and the ship’s velocity is 900 km/sec, the effective electron-collector radius is approximately 3 13 km. This appears to have a toroidal-field ramscoop as a prerequisite. For thrustless turning, a 0.06 degree turn requires a tether 10^3 km long: > To obtain a six-degree trajectory modification during a 1,400-year journey with the tether current assumed, the tether length must be increased by a factor of lOOX to equal l0^5 km. This would increase tether mass to 2.7 X lo5 kg. And this is using a reference ship many scientists are skeptical about: > ...it is assumed here that the primary propulsion for these ships is the ultra-thin, space manufactured solar sail unfurled as close to the Sun as possible at the perihelion of a parabolic or hyperbolic solar orbit. After acceleration to interstellar cruise velocity, it is also assumed that sail and cables are wound around the habitat section to provide extra cosmic ray shielding. The sail is unfurled again for deceleration at the destination star.... since the baseline sailcraft for this analysis is somewhat faster, either more advanced sail/cable materials are required or the pre-perihelion orbit is hyperbolic. I'd definitely categorize that under "experimental power sources and unproven physics." Perhaps you are thinking of a different article?
- GeneralMayhem 11y ago
  That would be a case of the "great filter" being in the future, no?
  - camikazeg 11y ago
    I've always read the "great filter" as some kind of mass extinction. I just think that the Fermi paradox gained popularity when everyone thought that both our travel speeds and our population would continue to grow exponentially, making space colonization both inevitable and necessary. What if we (and every other intelligent life) just level off when we start reaching the limits of physics and the available resources within our own solar system?
    - svachalek 11y ago
      I see it as a galactic cold war. On a galactic time scale, any civilization will reach a technology level of "maximum allowed by physics" relatively quickly, unless physics is indeed an infinite maze of rabbit holes. Therefore inter-species conflicts are resolved by mass/energy available. Any civilization that doesn't expand to interstellar levels of power is subject to the whims of those that do. If you can expand, you must.
clem 11y ago
Or, "We're deaf, blind, and isolated."
jsmeaton 11y ago
That was an incredible read. Thanks for sharing!

qrendel 11y ago

By some accounts we should probably be desperately hoping we are alone in the universe (at least with regards to technological civilizations), since it would mean the Great Filter is behind us rather than ahead. The alternative being we're very likely to go extinct before we get a chance to colonize the galaxy, and since that could probably be done using synthetic biology developed within the relatively near future, that would give our civilization an expected lifetime of less than a few hundred years at most. The more life that exists close to or surpassing our own level of development, the more bleak the future looks for our civilization.

DanAndersen 11y ago

I can understand the disappointment. It's helpful to always keep in mind that when it comes to discoveries, it's easy to hype ourselves up excessively. Recognize that the PR arms of scientific organizations and universities are also somewhat responsible. I find it helpful to remember that any Big Announcement like definite signs of life or advanced alien civilizations or asteroids hurtling toward Earth wouldn't be in such a small-scale announcement. You'd have the President appearing on TV or something.