I sometimes liken our civilisation as a reed mat floating across the pacific but with ants on it who have invented telescopes, and are trying their best to work out what sales are on at 5th Avenue - I love that we are “concerned” about atmospheric stripping millions of miles away - it gives me hope for those ants floating around
It seems like there are planets in most star systems. Even given what's been called a "gross underestimation" of 10^24 stars in the (observable) universe, even if you define some habitable zone based on our n=1 experience, even if you take some away based on the OP paper saying flares might make things a little harder at Prox, then that's still many Sagans* worth of planets, each of which gets a shot at growing telescope builders. That's a lot of chances.
Even if...we'd still be too far away to communicate in any meaningful way. If today we were to send a message equivalent to a signal flare, it would not be received within any of our lifetimes and some within any of our species' lifetime.
That's true. But there's a separate question, why no radio frequency evidence of other stars. I want to see some estimates of the liklihood of radio freq of some kind of communication in just our galaxy. How many stars might have earth-distanced planets from a sun - 6 billion in just our galaxy! Details below from a paper.
If there were this many, I hope in my lifetime we hear from some, just evidence of other intelligent life.
From 2019, it says using data from Kepler, they estimate that a close to earth sized planet (3/4 to 1.5 size of the earth) was in an orbit that could potentially have water vapor from a sun, orbital periods 327 to 500 days, with fairly large error bars:
* somewhere in the range of 1 of every 33 stars to as high as one such planet for every 1 out of 2 stars in our galaxy.
That's a large range, but given we have at least 200 billion stars in just our own Galaxy, that lower bound is about 6 billion stars with somewhat close to earth-distance planets, in just our galaxy. If this is over estimating by a million times, that's still 6 million planets in the earth like orbiting range. So let's make some noise, aliens.
The universe is ~14 billion years old. We didn't come along until a few million years ago, and then it took just until a hundred to two hundred years ago to be able to actually broadcast our existence. So if some other civilization had a similar timeline but much earlier, their signal could have come and gone by the time we could detect it. Their star could have also already reached the point where it destroyed its planet the civilization was located, so we'd never know about them. It's the same fate our planet has in store for it as well. If there's any civilization that comes after Earth's demise, they'd never know we were here either.
I sometimes liken our civilisation as a reed mat floating across the pacific but with ants on it who have invented telescopes, and are trying their best to work out what sales are on at 5th Avenue - I love that we are “concerned” about atmospheric stripping millions of miles away - it gives me hope for those ants floating around
What if we are the only ants in the ocean?
Isn't that super unlikely?
It seems like there are planets in most star systems. Even given what's been called a "gross underestimation" of 10^24 stars in the (observable) universe, even if you define some habitable zone based on our n=1 experience, even if you take some away based on the OP paper saying flares might make things a little harder at Prox, then that's still many Sagans* worth of planets, each of which gets a shot at growing telescope builders. That's a lot of chances.
* "billions and billions"
Even if...we'd still be too far away to communicate in any meaningful way. If today we were to send a message equivalent to a signal flare, it would not be received within any of our lifetimes and some within any of our species' lifetime.
That's true. But there's a separate question, why no radio frequency evidence of other stars. I want to see some estimates of the liklihood of radio freq of some kind of communication in just our galaxy. How many stars might have earth-distanced planets from a sun - 6 billion in just our galaxy! Details below from a paper.
If there were this many, I hope in my lifetime we hear from some, just evidence of other intelligent life.
Here's a paper that estimates the presence of these planets from the Kepler space observatory. https://www.icds.psu.edu/how-many-earth-like-planets-are-aro...
From 2019, it says using data from Kepler, they estimate that a close to earth sized planet (3/4 to 1.5 size of the earth) was in an orbit that could potentially have water vapor from a sun, orbital periods 327 to 500 days, with fairly large error bars:
* somewhere in the range of 1 of every 33 stars to as high as one such planet for every 1 out of 2 stars in our galaxy.
That's a large range, but given we have at least 200 billion stars in just our own Galaxy, that lower bound is about 6 billion stars with somewhat close to earth-distance planets, in just our galaxy. If this is over estimating by a million times, that's still 6 million planets in the earth like orbiting range. So let's make some noise, aliens.
This source says estimates are 200 to 400 billion stars in the milky way. https://bigthink.com/starts-with-a-bang/how-many-stars-milky...
The universe is ~14 billion years old. We didn't come along until a few million years ago, and then it took just until a hundred to two hundred years ago to be able to actually broadcast our existence. So if some other civilization had a similar timeline but much earlier, their signal could have come and gone by the time we could detect it. Their star could have also already reached the point where it destroyed its planet the civilization was located, so we'd never know about them. It's the same fate our planet has in store for it as well. If there's any civilization that comes after Earth's demise, they'd never know we were here either.
Been reading this gem of a blog for years. Happy to see it get some attention here.