"We've only been producing radio waves to send out there for 100 years, so that's assumed to be about the minimum time a civilization would have to be in existence and broadcasting for us to detect them.(bold mine) More realistically, the authors expect that a CETI population would have to exist for an average of 3,060 years to be detectable, which means that if life formed in both places at the same time, we'd both need to be in existence for 6,120 years to make contact. (my bold)

"'I think it is extremely important and exciting because for the first time we really have an estimate for this number of active intelligent, communicating civilizations that we potentially could contact and find out there is other life in the universe — something that has been a question for thousands of years and is still not answered," said co-author and astrophysicist Christopher Conselice of University of Nottingham."

David's Comment: Alpha centuri, the closest star is 4.3 light years away. Contact must be by radio waves at the speed of light. Very few stars are close enough, unless they produced radio waves thousands of years ago as discussed..

B-M: I always find these comments to be the most enlightening. We are assuming that if there is life it would have taken a similar technological progression to ourselves and would use the same technology or use physics in the same way. There is no real reason to think that, however.

Welcome back! I hope all is well with you and your family. As for enlightenment, just wait and see the results of my research, if I can only get the $1million I need to finish it.

"We've only been producing radio waves to send out there for 100 years, so that's assumed to be about the minimum time a civilization would have to be in existence and broadcasting for us to detect them.(bold mine) More realistically, the authors expect that a CETI population would have to exist for an average of 3,060 years to be detectable, which means that if life formed in both places at the same time, we'd both need to be in existence for 6,120 years to make contact. (my bold)

"'I think it is extremely important and exciting because for the first time we really have an estimate for this number of active intelligent, communicating civilizations that we potentially could contact and find out there is other life in the universe — something that has been a question for thousands of years and is still not answered," said co-author and astrophysicist Christopher Conselice of University of Nottingham."

David's Comment: Alpha centuri, the closest star is 4.3 light years away. Contact must be by radio waves at the speed of light. Very few stars are close enough, unless they produced radio waves thousands of years ago as discussed..

Tony: I always find these comments to be the most enlightening. We are assuming that if there is life it would have taken a similar technological progression to ourselves and would use the same technology or use physics in the same way. There is no real reason to think that, however.

The question always must come back to the biochemistry that is different and possible to create living matter. The usual conclusion is it must be carbon based life, silicon based won't hack it. Then would evolution follow different paths?

QUOTES: Researchers make a new estimate that the number of Earth-like planets in our Milky Way galaxy can reach us high as 6 billion.

While the scientists came up with an impressive number of possible Earths, this likely doesn't mean that's how many such planets there are and if they would have life like ours. But this new estimate definitely expands the possibility that similar planets are out there.

Taking into account what we do know, and mixing in some assumptions about life on Earth, a team of scientists have predicted that there are 36 Communicating Extra-Terrestrial Intelligent (CETI: pronounced "chetee") civilizations in our galaxy.

'I think it is extremely important and exciting because for the first time we really have an estimate for this number of active intelligent, communicating civilizations that we potentially could contact and find out there is other life in the universe — something that has been a question for thousands of years and is still not answered," said co-author and astrophysicist Christopher Conselice of University of Nottingham."

dhw: Oh golly gosh, this really is important and exciting. Nobody has a clue how many billion planets there are in the universe, and nobody has a clue whether any of them harbour life, but wowee we now have an estimate for the Milky Way. By sheer coincidence, I myself am developing a method for estimating the number of Earthlike planets in the entire universe (not just the Milky Way) and for predicting the number of INTELLIGENT CIVILIZATIONS (ICs: pronounced “Icies”) in our universe. This important and exciting research does, however, require funding, and so may I invite everyone who reads this important and exciting post to send at least $1000 to dhw’s FARCIC (Funding Astronomical Research Concerning Intelligent Civilizations) asap. Thank you.

Shouldn't we send pounds or euros?

Another thought that another reactions may create it:

https://www.scientificamerican.com/article/lifes-small-molecule-problem/?utm_source=new...

"...we don’t really know how microbes on Earth actually make phosphine: is it a direct product of metabolism or a consequence of metabolic products mingling with environmental chemistry? There is even evidence that ordinary iron, with phosphorus containing impurities, can react with sulfuric acid and produce plenty of phosphine at room temperature; an intriguing option for iron-rich meteoritic material raining onto acidic clouds.

***

"Even when you can go and collect samples directly, like on Mars or Venus, sniffing out anything but the simplest molecules is hard. If an ecosystem is sparse—as it might be in Venus’s cloud layers—you might have to spend a lot of time looking. Indeed, right here on Earth it’s taken us a shockingly long time to fully appreciate the presence and life cycle of atmospheric microbial life, and that’s when you can literally climb a mountain and grab samples.

"All of this may sound rather depressing for our quest to find life in the universe. But I think that there is something extremely interesting buried in the very fact that all of this is so terribly difficult. It is truly fascinating that life, which to us on a day-to-day basis is such a vibrant and explosive phenomenon, is also so very elusive. That’s true of the microbial world here on Earth as much as for elsewhere. What is it that makes life simultaneously so colorful but hidden?

"The answer may circle back to the statement I made previously, that life’s standout feature is that it uses and builds the most complex molecules we know of, from DNA to proteins. Complex molecules are naturally information-rich, in the truest most objective sense given by information theory and Shannon’s entropy. But they are also, in effect, deeply encrypted. DNA in a cell “decodes” itself with the help of an entire entourage of biochemical helpers. It’s taken us centuries to see how some of this works, and we’re far from finished.

Comment: Venus life or not? We need to go there to find out." The bold tells us about the problems we still have here in understanding life.