[X] My Assistant

[edstrick]

Richard Trigaux: ".... Too small stars like the Barnard star are also too red to give an efficient photosynthesis...."

Note that there is no problem in general with growing plants under incandescent lamps. The temperature of tungsten filaments is well under the temperature of red dwarf photospheres. The 99.9% bad astronomical art showing crimson red giants and red dwarfs is just that: Bad art.

Evolution on red-dwarf planets may well be pushed to "try" to evolve photosynthetic light absorbing systems that capture light beyond the "red-edge" of chlorophyll, where it's reflectance rises over 10 times from some 5% to some 50%, but that would not be necessary, just helpful.

[ljk4-1]

Do you guys realize the search terms that have been added in just the first 8 posts here?

little green men
UFO's
aliens
galactic civilizations
star wars
Vulcans
missing planets
attack with spacefaring technology
Independence Day
unsuspecting worlds
colonize the whole galaxy
Cosmic Zoos
Galactic Wildlife Parks
galactic scale civilisations
Earth-like civilizations

With that thinking, we better remove the word Mars from this forum, because we all know that will lead to the Mars Face!

On another SETI issue, are elements of art as universal as math?

http://www.jonlomberg.com/articles-Capri_paper.html

[Guest_Richard Trigaux_*]

Richard Trigaux:  ".... Too small stars like the Barnard star are also too red to give an efficient photosynthesis...."

Note that there is no problem in general with growing plants under incandescent lamps.  The temperature of tungsten filaments is well under the temperature of red dwarf photospheres.  The 99.9% bad astronomical art showing crimson red giants and red dwarfs is just that: Bad art. 

Evolution on red-dwarf planets may well be pushed to "try" to evolve photosynthetic light absorbing systems that capture light beyond the "red-edge" of chlorophyll, where it's reflectance rises over 10 times from some 5% to some 50%, but that would not be necessary, just helpful.

Thanks for the info, edstrick. If I understand well, stars are not really "red" or "yellow", but astrophysicists name them this way because the maximum radiation is in the red, or yellow, but this does not make the stars red or yellow.

And if the 3000°C tungsten lamps allow for photosynthesis, any star can do it, except some brown dwarves, the only stars below the 3000°C.

Back to my statistical analysis, there are perhaps 10 of 50 more time red dwarves than sun-like stars. This multiplies by the same figure the odds to develop photosynthesis (and further civilization).

The setback is that we are not sure that red dwarves have suitable planets. The most commonly accepted hypothesis is that they have, but we have no evidence, and the planets could be too small, from lesser mass and metallicity of the star. In the most extreme case, only recent high-metal yellow stars would have planets large enough to retain air and water. This mades in fact an uncertainty of 20 to 100 about the number of planets able to develop photosynthesis. With other sources of uncertainties, we easily obtain overal uncertainties of 1 over 1 billion about the total number of civilizations. And IN NO CASE we can state that we are closer from one extreme rather than from the other.


Red dwarves have other interesting features. Many are very old, as much as 12 billion years. And their overal evolution is much slower, so that the life-supporting period could last for 10 billion years, much more than for Earth (due to the slow evolution of the sun). So, if ancient red dwarves have suitable planets, we have the best chances to find something there. From where the interest of an effort to detect eventual Earth-like planets specially around close red dwarves, if possible with low metallicity.

[ElkGroveDan]

With that thinking, we better remove the word Mars from this forum, because we all know that will lead to the Mars Face! 
[/url]

The way google and other search engines work when you enter multiple search terms is that they look for frequency of terms on a page, as well as proximity of the terms to each other.

So a search for "Mars Pathfinder" or "Mars Opportunity" will likely turn up this site.

Prior to this thread, a search on "Mars alien civilization attacks by UFO's" would not have resulted in a hit here, it would have taken the kook to OTHER places.

[ljk4-1]

Thanks for the info, edstrick. If I understand well, stars are not really "red" or "yellow", but astrophysicists name them this way because the maximum radiation is in the red, or yellow, but this does not make the stars red or yellow.

And if the 3000°C tungsten lamps allow for photosynthesis, any star can do it, except some brown dwarves, the only stars below the 3000°C.

Back to my statistical analysis, there are perhaps 10 of 50 more time red dwarves than sun-like stars. This multiplies by the same figure the odds to develop photosynthesis (and further civilization).

The setback is that we are not sure that red dwarves have suitable planets. The most commonly accepted hypothesis is that they have, but we have no evidence, and the planets could be too small, from lesser mass and metallicity of the star. In the most extreme case, only recent high-metal yellow stars would have planets large enough to retain air and water. This mades in fact an uncertainty of 20 to 100 about the number of planets able to develop photosynthesis. With other sources of uncertainties, we easily obtain overal uncertainties of 1 over 1 billion about the total number of civilizations. And IN NO CASE we can state that we are closer to one extreme rather from the other.
Red dwarves have another interesting features. Many are very old, as much as 12 billion years. And their overal evolution is much slower, so that the life-supporting period could last for 10 billion years, much more than for Earth (due to the slow evolution of the sun). So, if ancient red dwarves have suitable planets, we have the best chances to find something there. From where the interest of an effort to detect eventual Earth-like planets specially around close red dwarves, if possible with low metallicity.

Have you seen the recent National Geographic Channel special titled Extraterrestrial? Its first hour depicts speculations about life on a planet
circling a red dwarf sun, complete with dealing with the issues of such stars
creating massive flares.

http://channel.nationalgeographic.com/chan...traterrestrial/

The Discovery Channel also came out with its own special on an alien world
and its life forms, based on the 1990 book Expedition by Wayne Barlowe, which you can learn more about here:

http://www.discoverychannelasia.com/alienplanet/index.shtml

[Guest_Richard Trigaux_*]

With that thinking, we better remove the word Mars from this forum, because we all know that will lead to the Mars Face! 

What I would like is that we could speak freely of this poetical trick of nature, and take it as our icon, without being mandatorily associated with kooks.

There are other such tricks on Mars, sometimes really puzzling: the Inca city, the pyramid, the smile, etc. And astronomers refer to them under these names, because it is much more convenient. That kooks would be able to forbid such a language is perhaps the most pervert effect of kookery.

[Guest_Richard Trigaux_*]

Have you seen the recent National Geographic Channel special titled Extraterrestrial?  Its first hour depicts speculations about life on a planet
circling a red dwarf sun, complete with dealing with the issues of such stars
creating massive flares.

http://channel.nationalgeographic.com/chan...traterrestrial/

The Discovery Channel also came out with its own special on an alien world
and its life forms, based on the 1990 book Expedition by Wayne Barlowe, which you can learn more about here:

http://www.discoverychannelasia.com/alienplanet/index.shtml

Interesting, and well done, I recommend the visit.

about flares, there are some stars which create huge flares, but we don't know why and why only these stars. Maybe the proportion of flare-prone red stars is higher, but really I have no information on this. The only thing sure is that our sun never did, otherwise we should not be here.

[Guest_Richard Trigaux_*]

The way google and other search engines work when you enter multiple search terms is that they look for frequency of terms on a page, as well as proximity of the terms to each other.

So a search for "Mars Pathfinder" or "Mars Opportunity" will likely turn up this site.

Prior to this thread, a search on "Mars alien civilization attacks by UFO's" would not have resulted in a hit here, it would have taken the kook to OTHER places.

perhaps that if the people who do searches like "Mars alien civilization attacks by UFO's" find this forum, they will get instruction, and realise that those who spread false theories are kooks.

Each time I was speaking of kooks on this site, it was alway about the spreaders of false theories. That 20% of the population believe them is not because 20% of the population are mad, it is because they are not enough instructed, or they are not confident with a society wich deceived them in a way or another. In such a situation, kooks have an easy play. If, with this forum, we can contribute to revert this situation, it would be of some use, not just a pass time for us.

A wise caution would be to use a language more accessible to common people, avoid "scientific style" and obscure abbreviations, and when we use an uncommon word, give the explanation. I began to do so recently , realizing that more and more people are reading us, not just specialist or enlightened amateurs.


Thas does not forbid to expell real kooks when there are some. Or to answer briefly but accurately to suspicious questions, as Doug used to do in many occasions. He did in this way, I think, to avoid to straightforwardly rebuff people who are just mislead by kooks, but who are not kooks themselves.

[deglr6328]

We probably should not be so quick to dismiss the possibility of photosynthesis on planets orbiting stars which dominantly radiate in the IR.....


article and the PNAS paper.

[jamescanvin]

perhaps that if the people who do searches like "Mars alien civilization attacks by UFO's" find this forum, they will get instruction, and realise that those who spread false theories are kooks.

Each time I was speaking of kooks on this site, it was alway about the spreaders of false theories. That 20% of the population believe them is not because 20% of the population are mad, it is because they are not enough instructed, or they are not confident with a society wich deceived them in a way or another. In such a situation, kooks have an easy play. If, with this forum, we can contribute to revert this situation, it would be of some use, not just a pass time for us.

A wise caution would be to use a language more accessible to common people, avoid "scientific style" and obscure abbreviations, and when we use an uncommon word, give the explanation. I began to do so recently , realizing that more and more people are reading us, not just specialist or enlightened amateurs.
Thas does not forbid to expell real kooks when there are some. Or to answer briefly but accurately to suspicious questions, as Doug used to do in many occasions. He did in this way, I think, to avoid to straightforwardly rebuff people who are just mislead by kooks, but who are not kooks themselves.

Well said Richard.

The kooks probably already have there sites and beliefs. It seems more likely to me that most people typing such terms into google are doing so to find out about the subject and are only potential kooks. If they head off to the kook site which tops the search then a new kook may be born; much better that they get directed here where we can persuade them otherwise.

[Guest_Richard Trigaux_*]

We probably should not be so quick to dismiss the possibility of photosynthesis on planets orbiting stars which dominantly radiate in the IR.....
article and the PNAS paper.

Wow! this is incredible.


Photosynthesis working with the radiation of nearby red-hot hydrothermal water... No sci-fi writer imagined such a thing!


That makes photosynthesis something much likely to appear. And in a statistic view of the Drake equation*, it increases the odds for civilizations. Not so fast, photosynthesis is just one of the numerous mandatory steps toward the appearance of a civilization. It is not enough for this, especially if it is available only around some very located hydrothermal vents, like in Earth deep oceans, or like in Europa moon. To evolve fast, life requires a lot of opportunities to mutate, and lot of different ecological niches to be able to select these mutations. So a complex environment, that a place like Europa is not likely to provide. On the other hand, Europa provides a stable environment since 4.5 billion years, and the bottom of its ocean may offer varied temperatures, shapes and chemical composition, if it has hydrothermal vents (very likely) or volcanoes (likely). So, if a microbial life appeared on Europa, it had enough time to evolve into complex multicellular beings. But no more brains than with worms or bugs, for the lack of a powerful source of oxygen.

* the Drake equation tries to calculate the number of civilizations in a galaxy, by multiplying various numbers such as the probablility for a star to have planets, the probability for this planet to have water, etc. Most of these numbers are still widely uncertain today.

[ljk4-1]

Paper: astro-ph/0511583

Date: Fri, 18 Nov 2005 21:35:43 GMT (30kb)

Title: Hot Jupiters: Lands of Plenty

Authors: David Charbonneau

Comments: 8 pages, 2 figures, summary of conference "The Tenth Anniversary of
51 Peg b: Status and Prospects for Hot Jupiter Studies", held August 22 - 25,
2005
\\
In late August 2005, 80 researchers from more than 15 countries convened for
a 4-day conference entitled ``The Tenth Anniversary of 51 Peg b: Status and
Prospects for Hot Jupiter Studies''. The meeting was held at l'Observatoire de
Haute-Provence, the location of the 1.93-m telescope and ELODIE spectrograph
used to discover the planetary companion to 51 Peg roughly 10 years ago. I
summarize several dominant themes that emerged from the meeting, including (i)
recent improvements in the precision of radial velocity measurements of nearby,
Sun-like stars, (ii) the continued value of individual, newly-discovered
planets of novel character to expand the parameter space with which the theory
must contend, and (iii) the crucial role of space-based observatories in
efforts to characterize hot Jupiter planets. I also present the returns of an
informal poll of the conference attendees conducted on the last day of the
meeting, which may be amusing to revisit a decade hence.

\\ ( http://arXiv.org/abs/astro-ph/0511583 , 30kb)

[ljk4-1]

I have been wondering whatever became of The Planetary Society's Project BETA Radio SETI program, begun ten years ago, ever since the 84-foot Harvard radio dish broke and fell during a windstorm in March of 1999.

The TPS Web site has an article from 2000 describing and showing a repair job undeway:

http://seti.planetary.org/BETA/default.html

But when I went to Harvard University's Oak Ridge Observatory site, I found out that the BETA dish has since been "retired":

http://cfa-www.harvard.edu/oir/OakRidge/oak.ridge.html

I also learned from there, to my surprise, that the 61-inch telescope that had conducted their Optical SETI program since 1998 has also been retired - retired in this case meaning dismantled!

Why didn't the TPS or Harvard or someone inform us about this?

A few years back, TPS began a new Optical SETI project with much fanfare. I looked on their Web site but could find no new updates on it since 2002 (with lots of broken links here), when it was supposed to have its "first light":

http://seti.planetary.org/OsetiConstruction2.htm

The latest version of their Optical SETI page also reveals no recent news on this project:

http://planetary.org/programs/projects/set...tical_searches/

So what is happening with what is supposed to be the "largest Optical SETI project east of the Mississippi"? Is it still being built? Is it up and running? Has it too been abandonded? Has the TPS been slipping away from SETI ever since Carl Sagan's passing, as I suspect?

I and many other have supported this project financially as well as verbally, so I would hope to at least know what progress is being made - and why BETA was abandonded. Why didn't TPS at least transfer it to another radio telescope?

[elakdawalla]

I have been wondering whatever became of The Planetary Society's Project BETA Radio SETI program, begun ten years ago, ever since the 84-foot Harvard radio dish broke and fell during a windstorm in March of 1999. 

Hi ljk4-1, all of these older projects that you mention unfortunately predate my joining the staff at The Planetary Society, and they're out of my usual purview, so I'm afraid I don't know any information to give you. I have forwarded your comments to the people here who particpate in the SETI projects.

I do know, however, that we continue to support SETI projects financially thanks to member dues and donations, and that we currently have active projects in optical and radio SETI, along with our other projects in technology development, Mars exploration, Near Earth Objecs searches, extralsolar planets, and others. The stuff on our website is a little thin right now because we just completed our redesign and have only filled out the barest skeleton of necessary content. I know that filling in more depth in the SETI section (as well as all the rest of the projects) is one of the priorities. Here's the most recent update from our Director of Projects, Bruce Betts, about our SETI work, which was published in the September/October 2004 issue of The Planetary Report:

We Make It Happen!
by Bruce Betts

The Search for Extraterrestrial Intelligence (SETI) has been actively pursued by the human species for more than 40 years . . . so why have we not found ET? In early August, The Planetary Society gathered major players in SETI, such as Frank Drake, Paul Horowitz, and Dan Werthimer, to address this question. In a scientific workshop titled “The Significance of Negative SETI Results,” SETI experts, astrobiologists, and planet hunters discussed what’s currently happening in SETI and what the future might hold. Here I review some of the broad conclusions, assumptions, and implications of the meeting.

Where Are We With the Search?
Rarely does the small SETI community get an opportunity to come together as a focused group. The first step of the workshop was to review what everyone there had done, was doing, and planned to do—and the accomplishments were impressive. When SETI started looking at radio wavelengths, people looked in only a few “channels” (think of different radio station channels). Now groups analyze billions of radio channels. Surveys of the whole sky have been completed around a few key wavelengths, and other searches have focused on a smaller number of stars with greater observing frequency or radio channel resolution. In addition, a whole new field of SETI has arisen in recent years: optical SETI. Whereas original searches focused only on radio frequencies, the invention of extremely high power lasers made several of the groups realize that laser communication across the cosmos could be very efficient.

I could spend an entire issue of The Planetary Report reviewing even just the Planetary Society–funded searches. Lacking that space right now, we will be putting both summaries of the talks, written by the speakers themselves, and their PowerPoint presentations on our website. I encourage you to keep checking seti.planetary.org for updates.

The Cosmic Haystack
The workshop discussed how far we’ve come in SETI and how much computing power is now being brought to bear on all the SETI searches. But what are we to make of the fact that 40 years have yielded exactly nothing in terms of finding ET?

What became clear was that despite all the advances in SETI, we’ve only just begun to search. As it turns out, the cosmic haystack in which we are searching for the ET needle is enormous. First, you need to choose a wavelength—even if you concentrate only on looking in the electromagnetic spectrum (all forms of “light” including gamma rays, visible light, and radio waves), you still have to make a choice what you’re looking for. Then there’s space—you can process and search only so many places in a certain amount of time, and there is a lot of sky up there. Then, there is time—even if you are searching the whole sky, you are searching only a piece at a time, so what if you’re not looking when ET is broadcasting? Finally, there have been hypothetical discussions of communication that, instead of using electromagnetic waves, uses something else such as gravity waves or particles or objects.

To be frank, we would have to have been really lucky to have found ET by now, even if there are lots of ETs out there broadcasting. And what if we’re missing the boat entirely in the approaches we’ve taken? If ET is broadcasting at infrared or millimeter wavelengths, we haven’t even been looking there, or not much. Why? Because a lot of this part of the electromagnetic spectrum is absorbed by our atmosphere. These wavelengths turn out to be efficient means to communicate across the cosmos, however, so perhaps using these wavelengths is very common for other civilizations. Space-based SETI, looking for signals from above the atmosphere, is an intriguing idea—one The Planetary Society plans to investigate further.

Humanity Is Quieting Down
There are interesting implications of the fact that our species has been quieting down in the electromagnetic spectrum. When SETI was starting out, there was quite a lot of “leakage” from Earth. Our TV and radio transmitters, and even defense radars, were putting out tens of kilowatts each, a good portion of which was spewed into space. But things are quieting down. Cable TV and satellite TV (which uses much less power) are starting to replace on-air broadcasting; defense radars have gone to “digital spread spectrum” technologies that, even if they do leak, are hard to discern from the noise of the universe. Even cell phone and other wireless technologies are focusing more on low power and on digital technology that uses lower power and requires clever work to decode.

If other civilizations follow a similar pattern—quieting down within decades after their invention of electromagnetic communication technologies—then leakage may be utterly impossible to detect as we search for ET. There was more optimism of leakage detection in the past. Now, most researchers think that detectable signals would be intentional beacons: ET sending out signals intentionally to let others know they are there.

Where Are We Going?
Although we’ve barely picked the surface of the haystack, we’ve come a long way in our capabilities in the last 40 years, and our capabilities are expected to expand massively in the coming decades, allowing us to churn through the hay faster and faster. Computing power is improving rapidly, telescopes are being built, and strategies are improving: life is good.

There’s even more good news—extrasolar planets. The meeting included discussions of planet finding around other stars, led by Geoff Marcy, whose planet-hunting team has discovered the majority of extrasolar planets found so far. Their searches have many interesting implications and have taught us much about how normal or anomalous our solar system may be (see planetary.org/extrasolar/ for more information). Estimates of the number of planets within our galaxy alone are at least in the tens of billions. That’s a lot of places where one might tuck away some advanced ET who wants to broadcast its version of Planetary Radio to the universe.

The searches continue, and they continue to improve. We’ll have lots more in The Planetary Report and on planetary.org about SETI searches and extrasolar planets. In addition to sponsoring SETI research, something that NASA still cannot legally do, The Planetary Society can put together special workshops like this one to facilitate advances in SETI. Searching for ET truly is looking for a needle in a haystack, but if we succeed, it arguably will be the most significant discovery in the history of our species. That’s a very big prize. With your help, we’ll continue the search. Will we find a signal from ET? I remain patiently but firmly optimistic.

[Bob Shaw]

The way google and other search engines work when you enter multiple search terms is that they look for frequency of terms on a page, as well as proximity of the terms to each other.

So a search for "Mars Pathfinder" or "Mars Opportunity" will likely turn up this site.

Prior to this thread, a search on "Mar5 a1ien c1vilization a77acks by U70's" would not have resulted in a hit here, it would have taken the kook to OTHER places.

All very true, and (hint!) perhaps a good reason *not* to quote the phrase directly!

Perhaps Doug can install the new Invision CensorBot ™ (if it exists) so that it can reject certain, er, words. Not thoughts, not deeds, just words - the very ones which feed the k00ks! There *are* such nanny-programs out there, and (famously) they have denied access to sensible sites about breast cancer, and (it has been alleged) the official website of Scunthorpe Town Council!

(Tongue slightly in cheek)

Bob Shaw