6 ms·

How a mysterious star could help the search for extraterrestrial life

48 points by rustoo 2y ago

bloopernova 2y ago
In this specific instance: The idea that astronomers had stumbled on such a structure triggered headlines round the globe – though not for long. Subsequent research has now undermined the idea. “We have found that light of different wavelengths is blocked in different amounts: exactly what you would expect from starlight passing through a dust cloud,” said Lintott.
- imglorp 2y ago
  It's not just some dust There's no way it's just some dust It was just some dust
  - pfdietz 2y ago
    I mean, if alien species could build star-spanning structures, they could easily do interstellar travel and colonization. So the Fermi argument says this couldn't actually have been aliens -- someone would have turned the Milky Way into a completely colonized urban area billions of years ago. All the other galaxies would have been colonized too (IR observations say < 1 in 100,000 have been urbanized.) I think people are misled by all the SF stories with galactic empires that somehow left Earth alone for billions of years, not realizing stories are there to entertain, not reflect what could be real.
    - jvanderbot 2y ago
      That's not clear actually. We could, given a religious like motivation, build massive space stations right now with today's rockets, materials, and lifetimes. It's incremental building. We could not get to the nearest star with today's rockets (or eq.), materials, or lifetimes. There's no incremental engineering there.
      - pfdietz 2y ago
        The star is just 1470 light years from our solar system. So, either a huge coincidence occurred, or there are many stars like this in the Milky Way. In the latter case, you are proposing that every one of the alien civilizations that built each of these things had the same motivational inhibition to colonization. Even more, you are proposing that all such civilizations in the past, and all such civilizations in other galaxies, were similarly inhibited. A star-spanning civilization would have far more than enough energy to propel interstellar vehicles, for example by laser beaming.
        jvanderbot 2y ago
        I'm proposing no such thing. GP said that if they had built large structures then it was obvious they could do interstellar travel. I said that implication was false, it's clear how we might build large orbital structures but not clear how we might to interstellar travel. As a counter example.
        pfdietz 2y ago
        The implication is as clearly true as such things could be. The barrier to interstellar travel is largely economic(*). The resources needed to construct star-spanning structures are many orders of magnitude greater than needed to construct and launch a starship (or a laser with an aperture capable of projecting a beam to interstellar distances). (*) https://galileo.phys.virginia.edu/classes/109.jvn.spring00/nuc_rocket/Dyson.pdf https://galileo.phys.virginia.edu/classes/109.jvn.spring00/n...
        jcranmer 2y ago
        One of the problems with this stuff is most of the problems are analyzed by physicists, who tend to reduce the problem to "can we make the physics work" rather than looking at more practical problems like "do we know if any materials will stand up to getting front-row seats to nuclear explosions?" and the other kinds of engineering problems that have bedeviled rocket science in its entire existence. And that's before getting into more fundamental issues like "what is the effect of space life on human biology?" (to which the answer appears to be somewhere between "maybe unmitigatably harmful" to "catastrophic"). There's a lot of questions that need to be answered before we can truly answer the question "what does it take to make interstellar travel", and the fact that many boosters for space exploration are glibly ignoring those questions is perhaps the biggest barrier of all.
    - fnordpiglet 2y ago
      This line of logic doesn’t hold. Star spanning structures requires the ability to move mass at scale which requires enormous but diffused in time and space amounts of controlled energy. Moving between stars requires immense energy focused on a single thing. The amount of acceleration required to any meaningful mass to speed necessary to travel between stars and maintain a coherent civilization is extraordinary and implies many things about the mass being accelerated as well. Most things would simply be crushed instantly, including any organism. The speed of light is also a major impediment as is time dilation, as is the need to decelerate, which require equal and opposite energy away from the destination. Ok - accelerate with large lasers based at home - how do you then stop? You first need to build large lasers both at home and destination. The problems expand, and this only helps for very local travel between close stars. It’s difficult but plausible with today’s technology scales up to build star spanning structures because they’re built incrementally and the need for near light speed travel doesn’t exist. Further the existence of a star spanning structure might enable interstellar travel, but not intergalactic. I’d also note that SF is meant to entertain with a story that is possible given some assumptions of progress or hidden nature of reality or small modifications to what is. It’s not meant to be built on magic and other absurdities (not meant as a pejorative!). Many science fiction stories become true and many more will. Often science fiction inspires us to achieve what doesn’t exist today but could. To couch it in something that’s dismissible as say Gandalf the Wizard fighting a Balrog is to greatly underestimate what science fiction is. It’s a roadmap to the future that helps us understand what to avoid on the road.
      - pfdietz 2y ago
        Building a starship reaching 1% of the speed of light seems quite reasonable without substantial technological advance (Dyson's 1968 H-bomb propelled Orion). What it would need would be lots of deuterium, but that's just a matter of large scale industry, which this putative civilization would have. If you are saying this civilization does its work over very extended periods of time, you're saying they're comfortable with efforts that take centuries or millenia or even longer. That alone makes interstellar travel and colonization much easier; the energy needed scales as the inverse square of the travel time (assuming Isp optimized for the travel time chosen and assuming non-relativistic travel). We (or they) do not need close to light speed travel for interstellar colonization.
- bilsbie 2y ago
  It’s not advanced alien technology because it doesn’t work like advanced alien technology.
  - bayouborne 2y ago
    It’s not advanced alien technology because it doesn’t work like our concept of advanced alien technology.
    - roywiggins 2y ago
      The Moon isn't a space station because it doesn't look like our concept of a space station. More likely it's just the Moon than an advance alien space station though.
jajko 2y ago
From wikipedia: It has been suggested that it is an alien megastructure, but evidence tends to discount this suggestion Just read wiki on the topic seems to be the best idea these days, much less pompous and no fabulation unlike the article. It also has distant red dwarf companion, of course no mention of this at all in the article. Not sure why guardian needs to chase sensationalism, I guess view count trumps all other metrics. Also, haven't heard any rational objections for Dark forest theory, any sufficiently advanced civilization to build this would be tremendously stupid to expose themselves to whole Milky way and few surrounding galaxies.
- bilsbie 2y ago
  Ducks: “evidence suggest duck blinds are just reeds” Which is a fun way to say the rules for evidence change a bit when what you’re studying could be actively deceiving you and is smarter than you. How do the rules change? No idea.
  - Nevermark 2y ago
    The big weakness of the Dark Forest scenario, is that if the galaxy was a dangerous place, it would already have been defensively/offensively explored. There wouldn’t be a star system with primitives like us that wasn’t identified many millions of years ago. But for credible scenarios, your “too much smarter than us to predict” principle is a good one. “They went into another dimension” for instance, seems fantastical. But we have no idea what millions of years of science and technology will allow. For all we know, the re-acceleration of dark energy is the side effect of successive new civilizations harnessing the fine structure of space-time creating their own private megaverses.
    - bilsbie 2y ago
      Do you pick apple blossoms or do you wait for the apples?
      - Nevermark 2y ago
        What does that mean? Super intelligent aliens want to wait millions of years to mess with us because … ? Whatever “apple blossoms” they want, they can create themselves. We don’t have unobtainium. We are never going to be a threat to life far more advanced than us. The solar system is just resources like any other, unless they leave more primitive life alone. Which would not be the Dark Forest scenario.

48 points by rustoo 2y ago

In this specific instance: The idea that astronomers had stumbled on such a structure triggered headlines round the globe – though not for long. Subsequent research has now undermined the idea. “We have found that light of different wavelengths is blocked in different amounts: exactly what you would expect from starlight passing through a dust cloud,” said Lintott.

imglorp 2y ago
It's not just some dust There's no way it's just some dust It was just some dust
- pfdietz 2y ago
  I mean, if alien species could build star-spanning structures, they could easily do interstellar travel and colonization. So the Fermi argument says this couldn't actually have been aliens -- someone would have turned the Milky Way into a completely colonized urban area billions of years ago. All the other galaxies would have been colonized too (IR observations say < 1 in 100,000 have been urbanized.) I think people are misled by all the SF stories with galactic empires that somehow left Earth alone for billions of years, not realizing stories are there to entertain, not reflect what could be real.
  - jvanderbot 2y ago
    That's not clear actually. We could, given a religious like motivation, build massive space stations right now with today's rockets, materials, and lifetimes. It's incremental building. We could not get to the nearest star with today's rockets (or eq.), materials, or lifetimes. There's no incremental engineering there.
    - pfdietz 2y ago
      The star is just 1470 light years from our solar system. So, either a huge coincidence occurred, or there are many stars like this in the Milky Way. In the latter case, you are proposing that every one of the alien civilizations that built each of these things had the same motivational inhibition to colonization. Even more, you are proposing that all such civilizations in the past, and all such civilizations in other galaxies, were similarly inhibited. A star-spanning civilization would have far more than enough energy to propel interstellar vehicles, for example by laser beaming.
      - jvanderbot 2y ago
        I'm proposing no such thing. GP said that if they had built large structures then it was obvious they could do interstellar travel. I said that implication was false, it's clear how we might build large orbital structures but not clear how we might to interstellar travel. As a counter example.
        pfdietz 2y ago
        The implication is as clearly true as such things could be. The barrier to interstellar travel is largely economic(*). The resources needed to construct star-spanning structures are many orders of magnitude greater than needed to construct and launch a starship (or a laser with an aperture capable of projecting a beam to interstellar distances). (*) https://galileo.phys.virginia.edu/classes/109.jvn.spring00/nuc_rocket/Dyson.pdf https://galileo.phys.virginia.edu/classes/109.jvn.spring00/n...
        jcranmer 2y ago
        One of the problems with this stuff is most of the problems are analyzed by physicists, who tend to reduce the problem to "can we make the physics work" rather than looking at more practical problems like "do we know if any materials will stand up to getting front-row seats to nuclear explosions?" and the other kinds of engineering problems that have bedeviled rocket science in its entire existence. And that's before getting into more fundamental issues like "what is the effect of space life on human biology?" (to which the answer appears to be somewhere between "maybe unmitigatably harmful" to "catastrophic"). There's a lot of questions that need to be answered before we can truly answer the question "what does it take to make interstellar travel", and the fact that many boosters for space exploration are glibly ignoring those questions is perhaps the biggest barrier of all.
  - fnordpiglet 2y ago
    This line of logic doesn’t hold. Star spanning structures requires the ability to move mass at scale which requires enormous but diffused in time and space amounts of controlled energy. Moving between stars requires immense energy focused on a single thing. The amount of acceleration required to any meaningful mass to speed necessary to travel between stars and maintain a coherent civilization is extraordinary and implies many things about the mass being accelerated as well. Most things would simply be crushed instantly, including any organism. The speed of light is also a major impediment as is time dilation, as is the need to decelerate, which require equal and opposite energy away from the destination. Ok - accelerate with large lasers based at home - how do you then stop? You first need to build large lasers both at home and destination. The problems expand, and this only helps for very local travel between close stars. It’s difficult but plausible with today’s technology scales up to build star spanning structures because they’re built incrementally and the need for near light speed travel doesn’t exist. Further the existence of a star spanning structure might enable interstellar travel, but not intergalactic. I’d also note that SF is meant to entertain with a story that is possible given some assumptions of progress or hidden nature of reality or small modifications to what is. It’s not meant to be built on magic and other absurdities (not meant as a pejorative!). Many science fiction stories become true and many more will. Often science fiction inspires us to achieve what doesn’t exist today but could. To couch it in something that’s dismissible as say Gandalf the Wizard fighting a Balrog is to greatly underestimate what science fiction is. It’s a roadmap to the future that helps us understand what to avoid on the road.
    - pfdietz 2y ago
      Building a starship reaching 1% of the speed of light seems quite reasonable without substantial technological advance (Dyson's 1968 H-bomb propelled Orion). What it would need would be lots of deuterium, but that's just a matter of large scale industry, which this putative civilization would have. If you are saying this civilization does its work over very extended periods of time, you're saying they're comfortable with efforts that take centuries or millenia or even longer. That alone makes interstellar travel and colonization much easier; the energy needed scales as the inverse square of the travel time (assuming Isp optimized for the travel time chosen and assuming non-relativistic travel). We (or they) do not need close to light speed travel for interstellar colonization.
bilsbie 2y ago
It’s not advanced alien technology because it doesn’t work like advanced alien technology.
- bayouborne 2y ago
  It’s not advanced alien technology because it doesn’t work like our concept of advanced alien technology.
  - roywiggins 2y ago
    The Moon isn't a space station because it doesn't look like our concept of a space station. More likely it's just the Moon than an advance alien space station though.

jajko 2y ago

From wikipedia: It has been suggested that it is an alien megastructure, but evidence tends to discount this suggestion Just read wiki on the topic seems to be the best idea these days, much less pompous and no fabulation unlike the article. It also has distant red dwarf companion, of course no mention of this at all in the article. Not sure why guardian needs to chase sensationalism, I guess view count trumps all other metrics. Also, haven't heard any rational objections for Dark forest theory, any sufficiently advanced civilization to build this would be tremendously stupid to expose themselves to whole Milky way and few surrounding galaxies.

bilsbie 2y ago
Ducks: “evidence suggest duck blinds are just reeds” Which is a fun way to say the rules for evidence change a bit when what you’re studying could be actively deceiving you and is smarter than you. How do the rules change? No idea.
- Nevermark 2y ago
  The big weakness of the Dark Forest scenario, is that if the galaxy was a dangerous place, it would already have been defensively/offensively explored. There wouldn’t be a star system with primitives like us that wasn’t identified many millions of years ago. But for credible scenarios, your “too much smarter than us to predict” principle is a good one. “They went into another dimension” for instance, seems fantastical. But we have no idea what millions of years of science and technology will allow. For all we know, the re-acceleration of dark energy is the side effect of successive new civilizations harnessing the fine structure of space-time creating their own private megaverses.
  - bilsbie 2y ago
    Do you pick apple blossoms or do you wait for the apples?
    - Nevermark 2y ago
      What does that mean? Super intelligent aliens want to wait millions of years to mess with us because … ? Whatever “apple blossoms” they want, they can create themselves. We don’t have unobtainium. We are never going to be a threat to life far more advanced than us. The solar system is just resources like any other, unless they leave more primitive life alone. Which would not be the Dark Forest scenario.