4 ms·

What's also crazy is if we did send a rover over there to hunt for life, and they found it, we'd have to wait 125 years to hear the result. We all sit around

What's also crazy is if we did send a rover over there to hunt for life, and they found it, we'd have to wait 125 years to hear the result. We all sit around knowing to listen to the skies sometime in October of 2185 to hear if the rover found life within the first month of its landing. If we ever send a team to live there, we'd hear broadcasts of their lives from 125 years prior. A real portal in time - so cool.

polishdude20 3y ago
2185? Not 2273?
jandrese 3y ago
Even worse if we are still limited by Newtonian dynamics it will take thousands of years for a probe to reach there. The rocket equation is a harsh mistress. In practical terms we will never visit that world without completely upending physics as we know it.
- holoduke 3y ago
  We just need a 1g rocket. Will take only a few days to get there. Life on earth will be 1000 years ahead once we are back though.
  - jandrese 3y ago
    The problem is when you work out the math on rocket that can sustain 1G for multiple days with any Earthly isp you realize the math just doesn't work. Even if you go nuts and plug in a number like 1 million seconds (our best chemical rockets are more like 450 seconds) for the isp it is still nowhere close to feasible using only the mass of our solar system. As long as you are stuck flinging mass out of the back of your rocket to accelerate you don't get to go anywhere outside of our solar system.
    - mr_toad 3y ago
      A beamed core proton-antiproton rocket could produce millions of ISP and allow accelerations of up to 0.7C, using relativistic mesons as the reaction mass. It is entirely theoretical though. https://ntrs.nasa.gov/api/citations/20200001904/downloads/20200001904.pdf https://ntrs.nasa.gov/api/citations/20200001904/downloads/20...
    - kjkjadksj 3y ago
      Dyson proposed a fusion pulse propulsion system in the 1960s that was estimated at 70000 isp. Maybe 1m wouldn’t have been that far off from the limits of these crafts if test ban treaties didn’t kill their development.
    - lapama 3y ago
      What about that strage propulsion system announced by caltech a few years back? Sorry really I have no more knowledge.
    - midoridensha 3y ago
      >The problem is when you work out the math on rocket that can sustain 1G for multiple days with any Earthly isp you realize the math just doesn't work. >our best chemical rockets are more like 450 seconds If we're talking about leaving the Solar system, and 1G rockets, why on Earth would you ever even think about primitive chemical rockets? Obviously, nuclear rockets are a mandatory first-step before getting close to that level of technology. And given that we already have nuclear power plants, as well as designs (untested) for nuclear rockets, why even bring up chemical rockets?
coffeebeqn 3y ago
How do you get the rover there? It would take thousands of years. Or maybe millions of years? With the current tech
- NoMoreNicksLeft 3y ago
  Orion drives can get up to some respectable fraction of the speed of light. Just need a billion or so 1-kiloton nukes. No biggy. No worries about sneaking up on them and startling them either.
  - floxy 3y ago
    "Roundtrip Interstellar Travel Using Laser-Pushed Lightsails" https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.1079.9524&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.10...
    - NoMoreNicksLeft 3y ago
      Ok, but let's bring along some nukes anyway, just for giggles.
- pg_bot 3y ago
  If you're traveling as fast as voyager 1, it would take over 2 million years to get there.
  - Aachen 3y ago
    The Voyagers didn't have today's ion engines. I don't know how much that gains us, though, as the main speed gain was by leeching momentum from planets' momenta, rather than from the hydrazine thrusters it carries
  - Jeff_Brown 3y ago
    Would it melt before then? Interstellar space is extremely thin, on the order of 1 atom per cubic centimeter (estimates vary). But, as we learned when Voyager finally left the solar system a few years ago, it is hot as hell. More than 54,000 degrees F according to National Geographic: https://www.nationalgeographic.com/science/article/interstellar-space-weirder-than-expected-nasa-voyager-2-reveals https://www.nationalgeographic.com/science/article/interstel...

polishdude20 3y ago

2185? Not 2273?

jandrese 3y ago

Even worse if we are still limited by Newtonian dynamics it will take thousands of years for a probe to reach there. The rocket equation is a harsh mistress. In practical terms we will never visit that world without completely upending physics as we know it.

holoduke 3y ago
We just need a 1g rocket. Will take only a few days to get there. Life on earth will be 1000 years ahead once we are back though.
- jandrese 3y ago
  The problem is when you work out the math on rocket that can sustain 1G for multiple days with any Earthly isp you realize the math just doesn't work. Even if you go nuts and plug in a number like 1 million seconds (our best chemical rockets are more like 450 seconds) for the isp it is still nowhere close to feasible using only the mass of our solar system. As long as you are stuck flinging mass out of the back of your rocket to accelerate you don't get to go anywhere outside of our solar system.
  - mr_toad 3y ago
    A beamed core proton-antiproton rocket could produce millions of ISP and allow accelerations of up to 0.7C, using relativistic mesons as the reaction mass. It is entirely theoretical though. https://ntrs.nasa.gov/api/citations/20200001904/downloads/20200001904.pdf https://ntrs.nasa.gov/api/citations/20200001904/downloads/20...
  - kjkjadksj 3y ago
    Dyson proposed a fusion pulse propulsion system in the 1960s that was estimated at 70000 isp. Maybe 1m wouldn’t have been that far off from the limits of these crafts if test ban treaties didn’t kill their development.
  - lapama 3y ago
    What about that strage propulsion system announced by caltech a few years back? Sorry really I have no more knowledge.
  - midoridensha 3y ago
    >The problem is when you work out the math on rocket that can sustain 1G for multiple days with any Earthly isp you realize the math just doesn't work. >our best chemical rockets are more like 450 seconds If we're talking about leaving the Solar system, and 1G rockets, why on Earth would you ever even think about primitive chemical rockets? Obviously, nuclear rockets are a mandatory first-step before getting close to that level of technology. And given that we already have nuclear power plants, as well as designs (untested) for nuclear rockets, why even bring up chemical rockets?

coffeebeqn 3y ago

How do you get the rover there? It would take thousands of years. Or maybe millions of years? With the current tech

NoMoreNicksLeft 3y ago
Orion drives can get up to some respectable fraction of the speed of light. Just need a billion or so 1-kiloton nukes. No biggy. No worries about sneaking up on them and startling them either.
- floxy 3y ago
  "Roundtrip Interstellar Travel Using Laser-Pushed Lightsails" https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.1079.9524&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.10...
  - NoMoreNicksLeft 3y ago
    Ok, but let's bring along some nukes anyway, just for giggles.
pg_bot 3y ago
If you're traveling as fast as voyager 1, it would take over 2 million years to get there.
- Aachen 3y ago
  The Voyagers didn't have today's ion engines. I don't know how much that gains us, though, as the main speed gain was by leeching momentum from planets' momenta, rather than from the hydrazine thrusters it carries
- Jeff_Brown 3y ago
  Would it melt before then? Interstellar space is extremely thin, on the order of 1 atom per cubic centimeter (estimates vary). But, as we learned when Voyager finally left the solar system a few years ago, it is hot as hell. More than 54,000 degrees F according to National Geographic: https://www.nationalgeographic.com/science/article/interstellar-space-weirder-than-expected-nasa-voyager-2-reveals https://www.nationalgeographic.com/science/article/interstel...