Gde su vanzemaljci?

[zakk]

Jesenja sezona tribinskog programa Centra za promociju nauke otvara se tribinom na temu ”Gde su vanzemaljci?”. Ciklus tribina sredom počinje 11. septembra u Velikoj sali Studentskog kulturnog centra, sa početkom u 19 časova. Ulaz je slobodan.


Budući da se u domaćoj nauci samo nekolicina astronoma bavi ovom temom, a da se NLO obično posmatra samo kao raširena zabluda, tribina predstavlja prvi naučnopopularni događaj u Beogradu koji o ovoj temi govori iz naučne perspektive.


Zahvaljujući tome, publika u Velikoj sali SKC-a će 11. septembra, u 19 sati, imati priliku da na tribini Centra za promociju nauke sazna više o vanzemaljcima iz ugla astronomije, biologije, opšte kulture, ali i iz ugla lovaca na NLO. Gde su oni danas? Kolika je verovatnoća da su već tu? Da li su nekada posetili Zemlju ili će to učiniti u budućnosti? Šta je SETI i kako se danas razvija potraga za vanzemaljskim životom?




Učesnici:


Branislav Vukotić, astronom, Astronomska opservatorija, Beograd
Igor Smolić, astronom, Institut za fiziku, Beograd
Voja Antonić, naučnopopularni pisac i slobodni konstruktor
Miroslav Kostić, NLO Srbija


Moderator:
Slobodan Bubnjević, Centar za promociju nauke


Specijalni gost
(sa specijalnim gostom razgovara Marija Nikolić, Centar za promociju nauke)




https://www.facebook.com/events/648200151870954/

[zakk]

Nadam se da specijalni gost nije mali zeleni iz Area51 

[Karl Rosman]

Koliko ja vidim Sloba Bubunjevic je vec tu... 

[sodomizer]

Verovatno...

[Meho Krljic]

Sumorna teza u odgovor na pitanje iz naslova topika:


    RIP E.T. – alien life on most exoplanets dies young    

Astronomers have found a plethora of planets around nearby stars. And it appears that Earth-sized planets in habitable zones are probably common.
So, with tens or even hundreds of billions of potentially habitable planets within our galaxy, the question becomes: are we alone?
Indeed, the search for alien life has become the holy grail for the next generation of telescopes and space missions to Mars and beyond. But could our search for E.T. be naively optimistic?
Many scientists and commentators equate “more planets” with “more E.T.s”. However, the violence and instability of the early formation and evolution of rocky planets suggests that most aliens will be extinct fossil microbes.
Just as dead dinosaurs don’t walk, talk or breathe, microbes that have been fossilised for billions of years are not easy to detect by the remote sampling of exoplanetary atmospheres.

Gaian BottleneckIn research published in the journal Astrobiology, we argue that early extinction could be the cosmic default for life in the universe. This is because the earliest habitable conditions may be unstable.
In our “Gaian Bottleneck” model, planets need to be inhabited in order to remain habitable. So even if the emergence of life is common, its persistence may be rare.
Mars, Venus and Earth were more similar to each other in their first billion years than they are today. Even if only one of the planets saw the emergence of life, this era coincided with heavy bombardment from asteroids, which could have spread life between the planets.
But about 1.5 billion years after formation, Venus started to experience runaway heating and Mars experienced runaway cooling. If Mars and Venus once harboured life, that life quickly went extinct.
Even if wet rocky Earth-like planets are in the “Goldilocks Zone” of their host stars, it seems that runaway freezing or heating may be their default fate.
Large impactors and huge variation in the amounts of water and greenhouse gases can induce positive feedbacks cycles that push planets away from habitable conditions.


The carbonate-silicate weathering cycle, which provides the major negative feedback to stabilise Earth’s climate today, was probably inoperative, or at least inefficient, until about 3 billion years ago.
However, life on Earth may have had the fortuitous ability to create stability by suppressing the positive runaway feedback loops and enhancing the negative feedback loops.
We should probably thank the unpredictable evolution of microbial communities our planet hosted early in its history for saving us from runaway conditions that would make Earth too hot or too cold for us to live.
As soon as life became widespread on Earth, the earliest metabolisms began to modulate the greenhouse gas composition of the atmosphere. It is no coincidence that methane, carbon dioxide, hydrogen and water are all potent greenhouse gases and also the reactants and products of metabolic reactions of the earliest microbial mats and biofilms.
The emergence of life’s ability to regulate initially non-biological feedback mechanisms (what we call “Gaian regulation”) could be the most significant factor responsible for life’s persistence on Earth.

Abiotic habitable zones are transientThe Earth is not the only planet in our galaxy with liquid water on its surface and energy sources and nutrients to enable life to form.
Although the universe is filled with stars and planets conducive to life, the absence of any evidence for alien life suggests that even if the emergence of life is easy, its persistence may be difficult.
Our work challenges conventional views that physics-based habitable zones provide stable conditions for life for many billions of years.
Although, the cottage industry of habitable zone modellers can turn various knobs that control atmospheric and geophysical properties to stabilise planets over short-timescales, they have mostly ignored the role of biology in keeping planets habitable over billions of years.
This is in part because the complexities of interactions between microbial communities that keep ecosystems stable are not sufficiently understood.
We hypothesise that even if life does emerge on a planet, it rarely evolves quickly enough to regulate greenhouse gases, and thereby keep surface temperatures compatible with liquid water and habitability.
Maintaining life on an initially wet rocky planet in the habitable zone may be like trying to ride a wild bull. Most riders falls off. So inhabited planets may be rare in the universe, not because emergent life is rare, but because habitable environments are difficult to maintain during the first billion years.

Most life dies youngOur suggestion that the universe is filled with dead aliens might disappoint some, but the universe is under no obligation to prevent disappointment.
We should not expect technological or spacefaring civilisations because there is no evidence that biological evolution converges to human-like intelligence. And subjective philosophical notions of life in the universe should not inform our estimates of the probability of life beyond Earth.
Superficially, these ideas seem to undermine the motivation for SETI and the recently announced Breakthrough Listen project.
Nevertheless, we support SETI because when we explore new regions of parameter space, we often find the unexpected.


n his book Pale Blue Dot, Carl Sagan reminded us that “in our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves”.
In the two decades since it was published, we’ve learnt that our cosmic backyard is littered with pale dots, probably in many colours of the rainbow. As we embark on the adventure of exploring our galactic neighbourhood with bigger and better telescopes, we may find only spooky planets haunted by long dead microbial E.T.s.

[Ana]

Sumorna teza u odgovor na pitanje iz naslova topika:

Evo sad i jedna zabavna. Nisam gledala ceo snimak, kažu u 28-ci.

http://www.24sata.rs/dokle-kratak-kurs-o-vanzemaljcima-na-nacionalnoj-frekvenciji/35829

[Labudan]

Американци! Где су ванземаљци?

[scallop]

Sumorna teza u odgovor na pitanje iz naslova topika:

Evo sad i jedna zabavna. Nisam gledala ceo snimak, kažu u 28-ci.

http://www.24sata.rs/dokle-kratak-kurs-o-vanzemaljcima-na-nacionalnoj-frekvenciji/35829

Ja bih najpre pitao gde je dokaz stručnosti nekog Petra Paunovića da može bilo čiju stručnost da komentariše. Potom, u tom istom programu sam se nagledao i naslušao lupetanja "stručnih" gostiju, pa nikom ništa. Ko se zabavio, zabavio se, ko nije nije ništa nabavio.

[Ana]

Ja videla kod Trivana, pa me razgalio i njegov komentar, i povod:

Ma jel' realno da na nacionalnoj frekvenciji slušamo ludaju koja je srela vanzemaljca u gradskom prevozu??! Doduše, u toj istoj emisiji gostuju i Vučić, Babić, Gašić... valjda su mislili da će se ludak utopiti među ostale ludake..

[Labudan]

Hoking: Šta ako kontaktiramo vanzemaljce a oni nas unište?

http://rs.n1info.com/a195763/Sci-Tech/Hoking-Sta-ako-kontaktiramo-vanzemaljce-a-oni-nas-uniste.html

[Meho Krljic]

Beteridžov zakon naslova kaže da odgovor mora biti "ne" ali lepo je spekulisati...


Was Venus the first habitable planet in our solar system?

Its surface is hot enough to melt lead and its skies are darkened by toxic clouds of sulphuric acid. Venus is often referred to as Earth’s evil twin, but conditions on the planet were not always so hellish, according to research that suggests it may have been the first place in the solar system to have become habitable.
The study, due to be presented this week at the at the American Astronomical Society Meeting in Pasadena, concludes that at a time when primitive bacteria were emerging on Earth, Venus may have had a balmy climate and vast oceans up to 2,000 metres (6,562 feet) deep.
Michael Way, who led the work at the Nasa Goddard Institute for Space Studies in New York City, said: “If you lived three billion years ago at a low latitude and low elevation the surface temperatures would not have been that different from that of a place in the tropics on Earth,” he said.
The Venusian skies would have been cloudy with almost continual rain lashing down in some regions, however. “So while you might get nice sunsets you would have mostly overcast skies during the day and precipitation,” Way added.
Crucially, if the calculations are correct the oceans may have remained until 715m years ago - a long enough period of climate stability for microbial life to have plausibly sprung up.
“The oceans of ancient Venus would have had more constant temperatures, and if life begins in the oceans - something which we are not certain of on Earth - then this would be a good starting place,” said Way.
Other planetary scientists agreed that, despite the differing fates of the two planets, early Earth and Venus may have been similar.


Professor Takehiko Satoh, who works on the Japan Aerospace Exploration Agency’s Venus Climate Orbiter (“Akatsuki”) mission, said: “Habitable or not, I’m not in a position to answer. Environment-wise, probably Venus once had an ocean and probably the environment of Venus and the Earth might have been similar.”
With an average surface temperature of 462C (864F), Venus is the hottest planet in the solar system today, thanks to its proximity to the sun and its impenetrable carbon dioxide atmosphere, 90 times denser than Earth’s. At some point in the planet’s history this led to a runaway greenhouse effect.
Previous US and Soviet landers sent to Venus have survived only a few hours on the surface before being destroyed.


Way and colleagues simulated the Venusian climate at various time points between 2.9bn and 715m years ago, employing similar models to those used to predict future climate change on Earth. The scientists fed some basic assumptions into the model, including the presence of water, the intensity of the sunlight and how fast Venus was rotating. In this virtual version, 2.9bn years ago Venus had an average surface temperature of 11C (52F) and this only increased to an average of 15C (59F) by 715m years ago, as the sun became more powerful.
More precise measurements of the chemical makeup of Venus’s surface and atmosphere could help establish how much water the planet had in the past, and when this began to disappear.
Some of this information may be filled in by the Akatsuki mission, which is observing the Venusian weather systems in unprecedented detail. The spacecraft was supposed to enter orbit about the planet in 2010, but after its main engine blew out, it instead spent five years drifting around the sun like a miniature artificial planet. Last year, scientists used altitude thrusters to redirect it into an orbit, and the mission could yet answer longstanding questions about our planetary neighbour, including whether it has volcanic activity, whether lightning strikes in the sky and why its atmosphere is rotating 60 times faster than the planet itself.
However, searching for traces of ancient microbial life would need a lander, and would be significantly more challenging.
“It would take a great deal of technology development, and money of course, to build the requisite landing craft to survive the surface conditions of present day Venus and to be able to dig into the surface,” said Way. “But if the investments were made it would be possible to search for such signs of life, including chemical traces.”
Details of the study are also published in the journal Geophysical Research Letters.

[Аксентије Новаковић]

Naučnici pronašli mesta u kosmosu odakle nas vanzemaljci posmatraju?

Astronomi su identifikovali devet planeta sa kojih bi inteligentni vanzemaljci mogli da nas posmatraju.

Dok je dosta vremena tokom godina posvećeno traženju znakova inteligentnog života u kosmosu, malo se razmatrala mogućnost da bi nas neko mogao posmatrati.

U nedavnoj studiji su naučnici iz Belfasta odlučili da saznaju koje su najbolje tačke gledišta za vanzemaljsku civilizaciju koja bi želela da posmatra naše ponašanje.

Istraživanje uključuje identifikovanje delova nebeskog prostora sa kojeg bi se mogle videti planete u našem sunčevom sistemu kako prolaze ispred sunca iz perspektive udaljenog posmatrača na drugom svetu.

Rezultati su pokazali da su stenovite planete poput Zemlje i Marsa najlakše za uočavanje.

„Veće planete bi prirodno blokirale više svetlosti kad prolaze ispred svoje zvezde,“ rekao je Robert Vels sa Kraljičinog univerziteta u Belfastu. „Međutim, bitniji faktor je zapravo koliko je planeta blizu svojoj roditeljskoj zvezdi. Kako su kopnene planete mnogo bliže suncu od gasovitih giganata, njih je lakše uočiti u tranzitu.“

Naučnici su na kraju identifikovali 68 vansolarnih planeta sa kojih bi bar neke planete našeg sunčevog sistema mogle biti posmatrane i bar 9 koje su na „idealnom mestu“ za posmatranje Zemlje.

Ni za jednu od ovih planeta se, pak, ne veruje da je naseljiva.

http://webtribune.rs/naucnici-pronasli-mesta-u-kosmosu-odakle-nas-vanzemaljci-posmatraju/

[Meho Krljic]

Biomarker for life found in space for the first time – and that's bad news

[ALEKSIJE D.]

Nemam pametnije mesto gde bih ovo okačio. Dakle, utorak, 27.3. na drugom programu Radio Beograda, drama koja nije trebala da bude snimljena, poslata kao zec, ne bi li mi prošla prava, komplikovanija, a ipak je privaćena iako je parodija, protivna svim principima radio drame:
   на програму:
 ДРАМСКИ ПРОГРАМ
   

ПАУКОВА МРЕЖА (Радио Београд 2 – 18.32)
Тихомир Стевановић: ПАРТИЈА БИЛИЈАРА

[Scordisk]

opaaa, čestitam! ovo bih rado preslušao, prethodne drame su mi bile odlične. nego, pošto neću biti kući, je l' znaš da li će ovo moći kasnije da se sluša, ili će biti okačeno negde?

[Filaret]

Одеш и региструјеш се на РТС Планета, још је бесплатно у земљи


https://rtsplaneta.rs/


Ту имаш радио и ТВ програме 72 сата уназад. Има и рецимо РТС Драма, коју ја немам на каблу.

[Scordisk]

eee, svaka ti se dala filarete! bravou!

[Meho Krljic]

Scientists discover bizarre hell planet where it rains rocks and oceans are made of lava

[scallop]

https://interestingengineering.com/scientists-find-mysterious-metal-monolith-in-utah-desert?utm_source=Facebook&utm_medium=Article&utm_campaign=organic&utm_content=Nov24&fbclid=IwAR2SQ4P6ZW2KzCMAvmg1Rc3mGmyWEHLzsWKLlkcSq6xh9018srtNivLQHeM

[mac]

monolit - objekat sačinjen od jednog kamena

metalni monolit - metalni objekat sačinjen od jednog kamena?

[scallop]

Jao, kako si ti pametan!

[varvarin]

Ajd sad da vas čujem, ljubitelji sporta!  (Tako kaže Stiven King.    )


https://www.b92.net/zivot/vesti.php?yyyy=2020&mm=12&dd=10&nav_id=1778430


Bivši šef svemirske divizije izraelske vojske Haim Eshed tvrdi da su Tel Aviv i Vašington kontaktirali "Galaktičku federaciju"vanzemaljaca i da zejedno vrše eksperimente na ljudima, ali da čovečanstvo još nije spremno za "istinu" o životu u svemiru.

Penzionisani general Haim Eshed (87), koji je bio na čelu svemirske jedinice Ministarstva odbrane Izraela gotovo tri decenije, tvrdi da postoji "vanzemaljski savez".
 "Vanzemaljci su tražili da se ne priča da su ovde, jer čovečanstvo još nije spremno", rekao je Eshed za izraelski list "Džudiot ahronot".

[scallop]

Zamisli šta ću ja da trtljam kroz devet godina. Još gore nego sada. Sad moram da ćutim o tome šta vole da pojedu kod nas kad navrate. Izazvao bih rat između vegana i ljubitelja roštilja. Pozajmljuju knjige i da li mi veruješ da najviše vole moje. Ponekad pitaju zašto kod drugih svi ubijaju svoje likove i da li bismo voleli da nam organizuju nešto slično da se radujemo.


Inače, taj Mosad je opaka firma. Sve znaju pre bilo koga. Rekli Trumpu u novembru 2019. da će pandemija početi u decembru. Sad pregovaraju sa vanzemaljcima i na ragovorima ih predstavlja lično Mojsije, jer ima potvrdu od Boga tri 'iljade godina.

[mac]

Moćni Tramp ne sme da zucne o vanzemaljcima, ali zato tamo neki general može da objavi knjigu o tome, i da je još i promoviše.

[scallop]

Sudbina generala je da kušuju dok su u uniformi, posle se raskokodaču i nose jaja.

[Meho Krljic]

US intelligence agencies have 180 days to share what they know about UFOs, thanks to the Covid-19 relief and spending bill

[Meho Krljic]

 An Astronomer Just Laid Out a Navigation System For Interstellar Space Travel

[Meho Krljic]

NASA announces team of scientists who will study mysterious ‘UFO’ events in the sky

[Meho Krljic]

Repeated signals from the center of the Milky Way could be aliens saying hello, new study claims

[Truba]

ti više ne postoje