6 ms·

> the camera will collect images of about 20 billion galaxies If there were intelligent like out there advertising it's presence, are we likely to detect it gi

> the camera will collect images of about 20 billion galaxies If there were intelligent like out there advertising it's presence, are we likely to detect it given the sheer quantity of sources?

jakear 6y ago
If one in 20 billion signals is transmitting a message in an encoding we don’t understand, on a time scale potentially completely different from our own.... I’m not confident.
- ido 6y ago
  I don't think we can realistically expect to detect anything beyond our galactic neighborhood- what could someone in another galaxy do to catch our attention? Trigger supernovas at an interval representing the Planck constant?
- digi59404 6y ago
  If an intelligent life form exists out there and is advanced enough to ponder the meaning of life and if there is other life... and is intelligent enough to know how to send messages across the universe... and to encode them... They would therefore be intelligent enough to know to/how to broadcast such a message in a way that can be universally understood.
  - mpoteat 6y ago
    Assuming it's possible both mathematically - in terms of an arbitrary encoding that we cannot explain away using standard physical phenomena e.g. quasars, and more importantly assuming it's actually possible from an engineering standpoint. All radio signals we send become indistinguishable from noise quite quickly.
dewitt 6y ago
> If there were intelligent like out there advertising it's presence, are we likely to detect it given the sheer quantity of sources? Humans are pretty intelligent. Intelligent enough to ask that question, anyway. So flip it around. If humans were to advertise our own presence to possible species living tens of billions of light years away, how would we go about doing it? Sadly, even if they noticed and wrote back, our sun will have since burned out, our time in this universe long past.
- RantyDave 6y ago
  I, also, have wondered this and came to the conclusion that you use whatever medium travels faster than light. Because until we discover that we're totally isolated anyway.
- realityking 6y ago
  > If humans were to advertise our own presence to possible species living tens of billions of light years away, how would we go about doing it? We‘ve been trying: https://en.m.wikipedia.org/wiki/List_of_interstellar_radio_messages https://en.m.wikipedia.org/wiki/List_of_interstellar_radio_m...
867-5309 6y ago
we are already trying to detect it. taking a photograph (or, recording a relatively narrow band of electromagnetic data) is not the best means of detection I expect this project is more geared towards detecting the geometry of the universe e.g. star and galaxy formation and evolution
- lolc 6y ago
  Maybe there is life with radically different physics from ours. And maybe they built some novelty galaxy constellations and our physicists will puzzle over those. "We've had to update our model of how galaxies form to include engineering as the most parsimonious explanation for SLAC 79813 and its satellites 79828 and 79829. Light from SLAC 79833 indicates only class O stars whereas both satellites seem to contain only class M stars. Very pretty! But no natural process except precise engineering on a cosmic scale could lead to such homogeneity. If our models are correct, tidal forces will stretch the two satellite galaxies into orthogonal tidal loops over the next billion years. It takes a species with significantly longer life-span than ours to appreciate the fireworks. But you can watch our simulation." Such unlikely discoveries might very well start with a photo of the sky.
  - 867-5309 6y ago
    where is that quoted from?
    - lolc 6y ago
      Nowhere. Sometimes I invent press releases I'd like to read.
      - 867-5309 6y ago
        nice
Laremere 6y ago
Doing the math with some quick Google searches... A single red photon has the energy 2.810-19 J. This sensor is for a telescope with the primary mirror size of 8.4 meters. So area ~ pi8.4m^2 = 221.7 m^2 (square meters) The distance to the closest galaxy, Andromeda, is 2.537 million light years = 2.4×10^22 meters If we assume it's a broadcast message (a poor guess for Andromeda, but reasonable for further galaxies), with energy projected in all directions, we can use the surface area of a sphere given a distance to get an idea for how much energy would need to be broadcasted to detect a single red photon: A=4πr^2 A = 4π * (2.4×10^22 meters)^2 = 7.238×10^45 m^2 (square meters) 7.238×10^45 m^2 / 221.7 m^2 * 2.8*10-19 J = 9.14136×10^24 J (joules) Wolfram alpha helpfully says that is "≈ ( 0.024 ≈ 1/42 ) × energy output of the sun in one second ( 1 s L_ )" Which is better than I expected, honestly. So, even for detecting life in the closest galaxy, an intelligent species would need to be working on the energy level of output of stars to have a hope of light reaching earth. Not even counting getting above the noise of the rest of the stars, and then sending something identifiable as intelligent.
- jiggawatts 6y ago
  Makes you wonder though... would it be possible to modulate the light from the star using a shutter-like mechanism in the direction you want to communicate? Imagine something like a DLP chip, but super thin: a reflective foil with tiny baffles that can be opened and closed using something like a simple electrostatic system. Make these into an enormous light-sail like sheet the same radius as the star. Place it between the star and the target system, and you have something akin to a signal lamp using the star as the light source. You don't need to generate power on the order of a star, you just need to modulate the light field of one. That's a much lower requirement. Bit of back-of-the-envelope maths is that this is 4*10^12 kg, assuming a sail the radius of our sun, 1 nm thick, and made of aluminium. That's a huge amount of mass, but conceptually manufacturable if using automated asteroid mining or somesuch. I feel like I'm making a mistake in my calculations for the energy requirements to toggle the shutters, but it's certainly low enough that embedded solar cells can trivially provide the energy required even if they're tiny and far apart.
  - Kye 6y ago

> the camera will collect images of about 20 billion galaxies If there were intelligent like out there advertising it's presence, are we likely to detect it given the sheer quantity of sources?

jakear 6y ago

If one in 20 billion signals is transmitting a message in an encoding we don’t understand, on a time scale potentially completely different from our own.... I’m not confident.

ido 6y ago
I don't think we can realistically expect to detect anything beyond our galactic neighborhood- what could someone in another galaxy do to catch our attention? Trigger supernovas at an interval representing the Planck constant?
digi59404 6y ago
If an intelligent life form exists out there and is advanced enough to ponder the meaning of life and if there is other life... and is intelligent enough to know how to send messages across the universe... and to encode them... They would therefore be intelligent enough to know to/how to broadcast such a message in a way that can be universally understood.
- mpoteat 6y ago
  Assuming it's possible both mathematically - in terms of an arbitrary encoding that we cannot explain away using standard physical phenomena e.g. quasars, and more importantly assuming it's actually possible from an engineering standpoint. All radio signals we send become indistinguishable from noise quite quickly.

dewitt 6y ago

> If there were intelligent like out there advertising it's presence, are we likely to detect it given the sheer quantity of sources? Humans are pretty intelligent. Intelligent enough to ask that question, anyway. So flip it around. If humans were to advertise our own presence to possible species living tens of billions of light years away, how would we go about doing it? Sadly, even if they noticed and wrote back, our sun will have since burned out, our time in this universe long past.

RantyDave 6y ago
I, also, have wondered this and came to the conclusion that you use whatever medium travels faster than light. Because until we discover that we're totally isolated anyway.
realityking 6y ago
> If humans were to advertise our own presence to possible species living tens of billions of light years away, how would we go about doing it? We‘ve been trying: https://en.m.wikipedia.org/wiki/List_of_interstellar_radio_messages https://en.m.wikipedia.org/wiki/List_of_interstellar_radio_m...

867-5309 6y ago

we are already trying to detect it. taking a photograph (or, recording a relatively narrow band of electromagnetic data) is not the best means of detection I expect this project is more geared towards detecting the geometry of the universe e.g. star and galaxy formation and evolution

lolc 6y ago
Maybe there is life with radically different physics from ours. And maybe they built some novelty galaxy constellations and our physicists will puzzle over those. "We've had to update our model of how galaxies form to include engineering as the most parsimonious explanation for SLAC 79813 and its satellites 79828 and 79829. Light from SLAC 79833 indicates only class O stars whereas both satellites seem to contain only class M stars. Very pretty! But no natural process except precise engineering on a cosmic scale could lead to such homogeneity. If our models are correct, tidal forces will stretch the two satellite galaxies into orthogonal tidal loops over the next billion years. It takes a species with significantly longer life-span than ours to appreciate the fireworks. But you can watch our simulation." Such unlikely discoveries might very well start with a photo of the sky.
- 867-5309 6y ago
  where is that quoted from?
  - lolc 6y ago
    Nowhere. Sometimes I invent press releases I'd like to read.
    - 867-5309 6y ago
      nice

Laremere 6y ago

Doing the math with some quick Google searches... A single red photon has the energy 2.810-19 J. This sensor is for a telescope with the primary mirror size of 8.4 meters. So area ~ pi8.4m^2 = 221.7 m^2 (square meters) The distance to the closest galaxy, Andromeda, is 2.537 million light years = 2.4×10^22 meters If we assume it's a broadcast message (a poor guess for Andromeda, but reasonable for further galaxies), with energy projected in all directions, we can use the surface area of a sphere given a distance to get an idea for how much energy would need to be broadcasted to detect a single red photon: A=4πr^2 A = 4π * (2.4×10^22 meters)^2 = 7.238×10^45 m^2 (square meters) 7.238×10^45 m^2 / 221.7 m^2 * 2.8*10-19 J = 9.14136×10^24 J (joules) Wolfram alpha helpfully says that is "≈ ( 0.024 ≈ 1/42 ) × energy output of the sun in one second ( 1 s L_ )" Which is better than I expected, honestly. So, even for detecting life in the closest galaxy, an intelligent species would need to be working on the energy level of output of stars to have a hope of light reaching earth. Not even counting getting above the noise of the rest of the stars, and then sending something identifiable as intelligent.

jiggawatts 6y ago
Makes you wonder though... would it be possible to modulate the light from the star using a shutter-like mechanism in the direction you want to communicate? Imagine something like a DLP chip, but super thin: a reflective foil with tiny baffles that can be opened and closed using something like a simple electrostatic system. Make these into an enormous light-sail like sheet the same radius as the star. Place it between the star and the target system, and you have something akin to a signal lamp using the star as the light source. You don't need to generate power on the order of a star, you just need to modulate the light field of one. That's a much lower requirement. Bit of back-of-the-envelope maths is that this is 4*10^12 kg, assuming a sail the radius of our sun, 1 nm thick, and made of aluminium. That's a huge amount of mass, but conceptually manufacturable if using automated asteroid mining or somesuch. I feel like I'm making a mistake in my calculations for the energy requirements to toggle the shutters, but it's certainly low enough that embedded solar cells can trivially provide the energy required even if they're tiny and far apart.
- Kye 6y ago