Winston
Lorenzo von Matterhorn
- Joined
- Jan 31, 2009
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My guess combines the following hypothesis with the Rare Earth hypothesis (the development of highly intelligent life let alone spacefaring life is extremely rare) combined with the additional possibility that many civilizations could be so far beyond us technologically because of their much earlier evolution that we could not detect them remotely unless they wanted us to. After all, IMO and that of others the smartest thing to do in an unknown neighborhood is to lay low. Also, even we could only detect our own RF emissions a mere one light year away and that is projected to constantly decrease due to fiber optic transmission and more efficient, high data rate, low power, spread spectrum, encrypted transmission methods that look like random noise, not even taking into account future quantum communications. Atmospheric evidence of technology present decreases with increasing efficiency of the use of raw materials and the use of energy sources like fusion. Evidence of possible non-technological life is easier via detection of highly reactive atmospheric gasses like oxygen and methane that need to be constantly replenished.
Where are all the aliens? Struggling and hustling, just like us
Conventional wisdom has it that aliens should be either everywhere, or nowhere. A new model suggests they can be both.
February 22, 2019
https://www.popsci.com/where-are-aliens-new-model
Excerpts:
The team calculated that for a civilization using ships just tens to thousands of times as fast as our vintage Voyager probes, the drifting of the stars shortens the time it would take to spread across the galaxy to a few hundred million years. Put another way, if you squeeze the galaxy’s existence into one calendar year, anyone launching ships by January 7 could have reached every star system by January 14. Now, on December 31, they are decidedly tardy.
This quick crossing time deepened the mystery of Fact A, until the researchers added two other reality checks. First, as Frank puts it, good planets may be hard to find. Some stars have no planets. Many planets may not fit your needs. Or, your dream planet may already be occupied.
Second, no single habitat can endure forever, as humanity is rapidly realizing. Spreading to other stars can extend a civilization’s overall lifespan, but from the moment a new settlement is born its days are numbered. It may last for hundreds of thousands or even millions of years, but at some point, a catastrophe almost certainly will take it out.
By considering a range of settlement lifespans, fractions of suitable planets, recharge times between launches, and other factors, the team calculated how much of the galaxy would end up settled for billions of potential galactic histories, and found three broad categories. The first two represent the common-sense solutions to the Fermi Paradox: If good planets are plentiful and survival is easy, the galaxy should overflow with life. If the opposite is true, no one gets very far.
Many of their simulations, however, fell into a third category—a Milky Way that remains partially settled indefinitely. Speeding across the galaxy in rapid waves may be easy, but administering that territory afterward is next to impossible. Settlements die out, drift apart, and vast swaths of space return to being uninhabited. Some get resettled, others don’t.
“You can end up with this loose network of settlements, Wright says, “where the whole galaxy is settled but any given star at any given moment might not be.”
We may happen to find ourselves in one of the zones that has remained untouched for at least millions of years (the authors point out that if Earth hosted a settlement deep in its geological past, no sign would remain today). If this is the case, Fact A needs no explanation.
Some still prefer other ways of resolving Fermi’s Paradox, such as Anders Sandberg, a researcher at the Future of Humanity Institute in Oxford, England, who suggests that life may just be vanishingly rare. He would like to see Frank’s simulations expanded to cover a wider range of possibilities. “It is a lovely model,” Sandberg wrote in an email, “but the authors restrict themselves to a fairly tight corner of possibility space.”
Astronomer Jill Tarter, whose work inspired Carl Sagan’s novel Contact, praised the team’s ability but questioned how far theoretical analyses can go. “They’re smart folks and probably got the math right,” she wrote in an email, “whatever that means in the absence of any data.”
The authors agree that no amount of theory can replace real searches, but say this analysis bolsters their optimism that technological life could exist in our galaxy, as well as their conviction that the astronomical community should go and look for it. Frank highlights the explosion of known planetary systems, with nearly 4,000 exoplanets discovered since 1992, and looks forward to researchers developing the ability to study these worlds in detail.
“We're going to look at these atmospheres and see if they have oxygen and methane,” Frank says, “and we may trip over a technosignature. For the first time in millennia of arguing about life on other planets, we live in an era where we’re actually going to have data.”
Full paper:
https://arxiv.org/pdf/1902.04450.pdf
Where are all the aliens? Struggling and hustling, just like us
Conventional wisdom has it that aliens should be either everywhere, or nowhere. A new model suggests they can be both.
February 22, 2019
https://www.popsci.com/where-are-aliens-new-model
Excerpts:
The team calculated that for a civilization using ships just tens to thousands of times as fast as our vintage Voyager probes, the drifting of the stars shortens the time it would take to spread across the galaxy to a few hundred million years. Put another way, if you squeeze the galaxy’s existence into one calendar year, anyone launching ships by January 7 could have reached every star system by January 14. Now, on December 31, they are decidedly tardy.
This quick crossing time deepened the mystery of Fact A, until the researchers added two other reality checks. First, as Frank puts it, good planets may be hard to find. Some stars have no planets. Many planets may not fit your needs. Or, your dream planet may already be occupied.
Second, no single habitat can endure forever, as humanity is rapidly realizing. Spreading to other stars can extend a civilization’s overall lifespan, but from the moment a new settlement is born its days are numbered. It may last for hundreds of thousands or even millions of years, but at some point, a catastrophe almost certainly will take it out.
By considering a range of settlement lifespans, fractions of suitable planets, recharge times between launches, and other factors, the team calculated how much of the galaxy would end up settled for billions of potential galactic histories, and found three broad categories. The first two represent the common-sense solutions to the Fermi Paradox: If good planets are plentiful and survival is easy, the galaxy should overflow with life. If the opposite is true, no one gets very far.
Many of their simulations, however, fell into a third category—a Milky Way that remains partially settled indefinitely. Speeding across the galaxy in rapid waves may be easy, but administering that territory afterward is next to impossible. Settlements die out, drift apart, and vast swaths of space return to being uninhabited. Some get resettled, others don’t.
“You can end up with this loose network of settlements, Wright says, “where the whole galaxy is settled but any given star at any given moment might not be.”
We may happen to find ourselves in one of the zones that has remained untouched for at least millions of years (the authors point out that if Earth hosted a settlement deep in its geological past, no sign would remain today). If this is the case, Fact A needs no explanation.
Some still prefer other ways of resolving Fermi’s Paradox, such as Anders Sandberg, a researcher at the Future of Humanity Institute in Oxford, England, who suggests that life may just be vanishingly rare. He would like to see Frank’s simulations expanded to cover a wider range of possibilities. “It is a lovely model,” Sandberg wrote in an email, “but the authors restrict themselves to a fairly tight corner of possibility space.”
Astronomer Jill Tarter, whose work inspired Carl Sagan’s novel Contact, praised the team’s ability but questioned how far theoretical analyses can go. “They’re smart folks and probably got the math right,” she wrote in an email, “whatever that means in the absence of any data.”
The authors agree that no amount of theory can replace real searches, but say this analysis bolsters their optimism that technological life could exist in our galaxy, as well as their conviction that the astronomical community should go and look for it. Frank highlights the explosion of known planetary systems, with nearly 4,000 exoplanets discovered since 1992, and looks forward to researchers developing the ability to study these worlds in detail.
“We're going to look at these atmospheres and see if they have oxygen and methane,” Frank says, “and we may trip over a technosignature. For the first time in millennia of arguing about life on other planets, we live in an era where we’re actually going to have data.”
Full paper:
https://arxiv.org/pdf/1902.04450.pdf
