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Michael Watson

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Message 1753279 - Posted: 2 Jan 2016, 18:19:43 UTC
Last modified: 2 Jan 2016, 19:15:55 UTC

Welcome to the forum, Dave Hamann.
The planned scrutiny of the star KIC 8462852 by the SETI Institute, mentioned in that article, has since been carried out. Nothing noteworthy was detected. They were hoping for a very powerful signal, pointed in our direction, but could have missed other sorts of signals.
Other, more sensitive searches of this star, from other observatories, are proposed in the near term.
See a link, below, to a follow-up article from the same journal:
http://www.ibtimes.co.uk/alien-megastructures-seti-finds-no-radio-signals-kic8462852-wont-rule-out-civilization-1527877
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Message 1753808 - Posted: 4 Jan 2016, 8:10:01 UTC - in response to Message 1753279.  

Welcome to the forum, Dave Hamann.
The planned scrutiny of the star KIC 8462852 by the SETI Institute, mentioned in that article, has since been carried out. Nothing noteworthy was detected. They were hoping for a very powerful signal, pointed in our direction, but could have missed other sorts of signals.
Other, more sensitive searches of this star, from other observatories, are proposed in the near term.
See a link, below, to a follow-up article from the same journal:
http://www.ibtimes.co.uk/alien-megastructures-seti-finds-no-radio-signals-kic8462852-wont-rule-out-civilization-1527877

Seems like we are too far & don't have enough powerful receivers to detect some signal...like it's said in the text!
;)


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Michael Watson

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Message 1753895 - Posted: 4 Jan 2016, 18:03:26 UTC
Last modified: 4 Jan 2016, 18:22:12 UTC

The SETI Institute monitoring of the 'Tabby's star' system didn't really establish that there are no intelligent signals that can be detected with any present receivers. They listened briefly with 20 of their 42 small dish antennas.
They merely sought to determine if a very powerful signal was present. It wasn't, at least at the times they listened. More sensitive receivers may find a signal, if they can be used for this search. Such searches have been proposed. it is hoped that these will be possible in the near term.
The Very Large Array, in New Mexico, and the (Byrd) Green Bank telescope, in West Virginia have been mentioned as possibilities. Just to give a rough idea of their relative sensitivity: The Green Bank radio telescope has about 13 times the collecting area of the portion of the Allen Telescope Array that the SETI Institute used in their search. The entire Very Large Array has about 22 times this collecting area .
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Message 1754527 - Posted: 7 Jan 2016, 9:26:57 UTC - in response to Message 1753895.  
Last modified: 7 Jan 2016, 9:27:46 UTC

The SETI Institute monitoring of the 'Tabby's star' system didn't really establish that there are no intelligent signals that can be detected with any present receivers. They listened briefly with 20 of their 42 small dish antennas.
They merely sought to determine if a very powerful signal was present. It wasn't, at least at the times they listened. More sensitive receivers may find a signal, if they can be used for this search. Such searches have been proposed. it is hoped that these will be possible in the near term.
The Very Large Array, in New Mexico, and the (Byrd) Green Bank telescope, in West Virginia have been mentioned as possibilities. Just to give a rough idea of their relative sensitivity: The Green Bank radio telescope has about 13 times the collecting area of the portion of the Allen Telescope Array that the SETI Institute used in their search. The entire Very Large Array has about 22 times this collecting area .

so we wait a little...

but according to my calcs, L4 or L5 points of an Earth size planet around Tabby star should dim the Tabby star now...why nobody is checking it?!
:/


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Profile Tiers Jean-Francois
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Message 1754904 - Posted: 8 Jan 2016, 18:16:26 UTC - in response to Message 1734425.  

Hello all.
This note is a bit far from the present and exciting topic, but I do not where else to post it.

NASA claimed a few monthes ago they had discovered an Earth-like planet (size, density, orbit allowing liquid water all its year long, etc.)
But, as far as I know, they didn't report that this planet has a moon.
I mean, a moon like our's.
This might drop down our enthousiam in the quest of Little Green Men...

Just remember : Earth was born just after our Sun (4.5 billion years ago) and 4.4 billion years ago it was hit by Theia, a planet with the size of Mars, at the speed of 20 km/s (kind of speed usual for NEO's).
Not only the strike changed the rotation speed and axis of Earth but it also created the Moon.
With its diameter over 3,000 km Moon is quite a giant satellite for a telluric planet.

So, what else ?
Maybe something, maybe nothing...
The tide effect due to the Moon is still huge compared to others (Sun and Jove) and was much more at the very begining of the movie (Moon was only at 20,000 km when Earth was more or less liquid).
As a result, the heavy radioactive elements synthetized in super novas did not stand only in the Earth's nucleus as they should have done without the strong additional volcanic activity due to Moon tides (I have been told, when at the University, that volcanic areas exhibit more natural radioactivity than other areas).
Today more than 4 billion tons of uranium are scattered in the seas and in the upper mantle of earth, just at our feet.
The same for thorium 232 even if its amount doesn't seam definetely determined yet.
Of course, uranium is mostly 238 (just heavy) and its isotope 235 (radioactive) is quite few in comparison.
But the natural surface radioactivity remains much higher than it would have been without the Moon and could have increased noticeably the mutation rate of living beings (vegetals and animals) explaining (?) both the emergence speed of new species and the biodiversity of our planet.
Terrestrial life appeared only around 730 million years ago and before only submarine life existed. Even though there were (and still are) radioactive elements in the oceans, the subatomic particles are absorbed much more by water than by air.
Then, "slow" mutations in the seas and "fast" mutations on the solid ground.

Question : without this radioactivity, would the homo sapiens have had the time to come in such a short time ? (Lucy is 3 million years old, Tumai - if he can be considered as human - is 6 m.y.)

Isaac Asimov put this hypothesis on the table decades ago in his Foundations saga.
I do not know if this hypothesis has been verified or infirmed by scientists in between but if he was right, no giant moon means a few chances to have a "almost like-us" life there.

I am not an astronomer, nor a biologist, and I am hungry to get the opinions or reactions of the SETI community members.

Many thanks in advance and sorry for this too long note.
Cheers.
Tiers
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Message 1754966 - Posted: 8 Jan 2016, 23:02:21 UTC - in response to Message 1754904.  

Short answer: Even if said planet were orbiting the closest star to us - Proxima Centuari - we still wouldn't be able to see if it has any moons.

Life on Earth would have been different had we not had a moon, but I don't think terrestrial radiation was a factor in the chain of mutations that led to modern humans. Radiation can cause mutation, but mutation in biological systems is inevitable and doesn't require radiation to trigger it.
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Message 1755072 - Posted: 9 Jan 2016, 12:29:47 UTC

Also note that Life on Earth-like moons around Jovian planets in Habitable areas is also a possibility!
Why? Same tidal shift of waters...almost same parameters!
;)


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Profile Tiers Jean-Francois
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Message 1755076 - Posted: 9 Jan 2016, 13:32:24 UTC - in response to Message 1754966.  

Thanks a lot for your post.
Anymay, I still have a doubt.

I accept that mutations must be mostly "errors" (copy/paste) in ADN duplication but we also all know the consequences of strong irradiation effects (Tchernobyl, Fukushima and possibly others we were not advised), showing I suppose that irradiation causes mutations.
Each time the result was a being with less possibilities and exhibiting handicaps (among those : sterility, then end of the future for his new "specie").
But is it definitely stupid to consider that in the course of time (730 million years for ground life), radio mutations with reasonably weak irradiation level could from time to time (with a very low probality, I admit) have given a "better" (I mean more adaptable) creature ?
Are there publications stating that only the copy/paste ADN errors can explain we (homo sapiens sapiens) are here ? I am hungry to know, just for I have no personal absolute conviction ! Just curiosity and the wish to understand more.

Cheers and thanks again.
Tiers
PS : I do not belong to any sect giving the Moon magical powers !
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