ZNAK SAGITE — više od fantastike — edicija, časopis, knjižara...

Problem s gravitacijom je u tome što se ona ravnomerno (prema formuli) distribuše u prostoru, tj. nema pravolinijski smer, a masa ne mora da bude pravilno raspoređena u prostoru. Neki tvrde da je masa Meseca neravnomerno raspoređena i da je njegova gravitacija različita na različitim mestima. Zbog toga su u početku spuštanja na Mesec bila neuspela, jer je računata slabija gravitacija, a izgleda da je bila znatno veća od 1/6 Zemljine.

Takođe, treba znati da gravitacija koja pripada "masi" postoji i izvan te mase (kao dejstvo), u okolnom prostoru, pa se to dejstvo sabira i dobija se "tačka težišta" koja može da bude i u praznom prostoru.

Dakle, dovodi se u sumnju tvrdnja da je gravitacija osobina mase - može da bude i nešto drugo u pitanju. Videćemo da li će da nađu tu Božansku Bozu ovi u Cernu, pošto očigledno nisu sigurni šta je zapravo "izvor" gravitacije.

http://peswiki.com/index.php/PowerPedia:Tesla%27s_Dynamic_Theory_of_Gravity

Ovaj tip je dosta spekulisao i dokazivao, ali ja nisam stručan da bih mogao da mu u potpunosti verujem. Međutim, dosta je zanimljivo to što priča.

Quote from: Boban on 12-09-2010, 17:21:56
Pa ako u formuli za određivanje gravitacije figurira poluprečnik na kvadrat; nikako ne može biti linearna veza. Drugim rečima, ista masa, duplo veći prečnik znači četiri puta manju gravitaciju.

...i osam puta manju gustoću. Dakle, da Zemlju raztegneš na dupli promjer bez dodavanja mase, mogla bi plutati na vodi.

Nego, o čemu mi ovdje uopće raspravljamo?

ali gustina nema nikakve veze sa masom, zapravo ima matematički u određivanju kolika je masa, ali već određena masa daje određenu gravitaciju na određenoj udaljenosti od centra mase. U svakom slučaju dolazimo do šupljeg nebeskog tela za početni zahtev.

Masa Jupitera je 317.8 Zemljinih masa, ali gravitacija na površini ekvatora (mada ne znam šta im to znači "površina" na Jupiteru) je svega 2.528 g.

Gustina mu je skoro pet puta manja od Zemljine.

http://www.newscientist.com/article/mg21028154.200-when-the-multiverse-and-manyworlds-collide.html?full=true

QuoteCosmologists reconcile this seeming contradiction by assuming that the superposition eventually "collapses" to a single state. But they tend to ignore the problem of how or why such a collapse might occur, says cosmologist Raphael Bousso at the University of California, Berkeley. "We've no right to assume that it collapses. We've been lying to ourselves about this," he says.

Dosta je bilo PRETPOSTAVKI. Da li su se ti naučnici konačno osvestili????

Dosta s lagarijama...  

Ceo tekst.

http://arxiv.org/PS_cache/arxiv/pdf/1105/1105.3796v1.pdf

Ne samo što su Srbi sada stvarno narod najstariji u Europi (ili bar imaju najstarije stanovništvo), nego astronomi sad tvrde i da je naš svemir toliko star da je skoro potpuno prestao da proizvodi nove zvezde:

Study: The Universe Has Almost Stopped Making New Stars 

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By Ian Steadman, Wired UK
Most of the stars that will ever exist have already been born, according to the most comprehensive survey of the age of the night sky.


An international team of astronomers used three telescopes — the UK Infrared Telescope and the Subaru Telescope, both in Hawaii, and Chile's Very Large Telescope — to study trends in star formation, from the earliest days of the universe. Extrapolating their findings has revealed that half of all the stars that have ever existed were created between 9 and 11 billion years ago, with the other half created in the years since. That means that rate at which new stars are born has dropped off massively, to the extent that (if this trend continues) 95 percent of all the stars that this universe will ever see have already been born.

Several studies have looked at specific time "epochs", but the different methods used by each study has restricted the ability to compare their findings and discern a fuller model of how stars have evolved over the course of the entire universe's lifespan.

We do know that many stars around today — including our own — likely formed out of the dust left over from earlier, bigger stars going supernova in the early years of the universe. The problem was figuring out exactly how many stars the universe used to give birth to relative to how many are born in later years, as it seemed that at some point there was a steep drop off in the creation of new stars.
The telescopes searched for alpha particles emitted by Hydrogen atoms (commonly found in star formation, appearing as a bright red light) throughout huge patches of sky. Snapshots were taken of the look of the universe at defined different points in time, when it was 2, 4, 6 and 9 billion years old — a sample that's 10 times as large as any previous similar study.
The results showed clearly that half of all the stars that have ever existed in the universe were created more than 9 billion years ago, with the remaining half coming into existence since then. On the Subaru Telescope's site, the study's lead author, Leiden University's David Sobral, writes: "The production of stars in the Universe as a whole has been continuously declining over the last 11 billion years; it is 30 times lower today than at its likely peak 11 billion years ago. If this trend continues, no more than five percent more stars will exist in the Universe. We are clearly living in a Universe dominated by old stars. All of the action in the Universe occurred billions of years ago!"
Importantly, it also provides a way to reconcile the previously confusing disparity between the number of stars we can observe and the number of stars we know should have been created by the universe. The first generations of stars would have been extremely large — many hundreds of times larger than our Sun — and would have burned through their fuel quickly, undergoing supernovae death and providing the scattered discs of dust that later stars and planetary systems will have formed out of.
The findings map onto this, showing a huge rate of star formation which slowed rapidly after the first generation 9 billion years ago. It then took almost five times as much time for the same number of stars to be born again, accounting for the second half of all observed star formation. Findings from other studies into star formation — which used smaller sample sizes, or different methods — also fit onto the graph that the team derived, reinforcing the "huge early peak then rapid decline" theory. The study has been published in the Monthly Notices of the Royal Astronomical Society, and is available to read here.
Unfortunately, then, it looks like our universe is running out of steam — in only a few more billion years, the study predicts, we may well be seeing the very last star that will ever be born. That's if humans manage to survive that long, of course.

Nema veze, pravićemo mi veštačke zvezde.

...od blata.

Za jedne blato, za druge materijal za fuziju

Sad pokušavam da se setim u kojoj beše priči ili romanu detoniraju bombu u srcu Jupitera, da bi od njega napravili zvezdu...

druga Odiseja?

Није било бомбе у "Другој одисеји", већ монолити заврше посао. И настане Луцифер.

znam, nego kontam da je možda NF mislio na to. nema veze...

Updated model for identifying habitable zones around stars puts Earth on the edge

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Researchers at Penn state have developed a new method for calculating the habitable zone around stars. The computer model based on new greenhouse gas databases provides a tool to better estimate which extrasolar planets with sufficient atmospheric pressure might be able to maintain liquid water on their surface. The new model indicates that some of the nearly 300 possible Earth-like planets previously identified might be too close to their stars to to be habitable.
So far, scientists have found some 18,000 extrasolar planet candidates with only a handful of these the right size, distance and having the proper orbital characteristics to be potentially habitable. "Habitable" is very broadly defined as being very approximately the right size and having a temperature where liquid water could exist on the surface of the planet. It's a very generous definition, but it's still one that leaves a very large margin of error.
Part of the reason is the variables the scientists use to calculate the habitable zone. One half of the equation is the star itself. Is it old? Is it young? Is it hot? Is it cool? Is it a variable? These determine how far the habitable zone is from the star and how wide it is. Then there is the planet itself, with characteristics such as size and temperature used to fine tune the estimates.
The Penn State model is based on previous work by James Kasting, Evan Pugh Professor of Geosciences also at Penn State. In the current study, the habitable zone is calculated based on stellar flux incident on a planet, that is, the amount of light falling on it, instead of its equilibrium temperature.
It is not, however, a way of coming up with a simple temperature reading. Instead, it's a complex computer model based on assumptions about the atmosphere of the planet and how it absorbs and radiates heat under given conditions. Even though these calculations are so involved they need a supercomputer to carry them out, they are still very simplified compared to reality and operate on a number of assumptions. For example, this study assumes a one-dimensional, radiative-convective, cloud-free climate. The team themselves admit that some factors may have been under or overestimated and the results will reflect this.
The team used updated absorption databases of greenhouse gases, such as carbon dioxide and water vapor, that are more accurate than those used by Kasting 20 years ago. These were fed into supercomputers at Penn State and the University of Washington and from this the habitable zone was calculated for various classes of stars.
The habitable zone was calculated between the point where the planet would be so hot that water would be hopelessly lost (the inner limit) and the point where the greenhouse effect would be too weak to melt ice (the outer limit). The results of the Penn State study indicate that the habitable zones are farther away from their stars than previously thought. This means that some extoplanets previously thought to be potentially habitable might not be so.
One disturbing finding of the study was that the Solar System's habitable zone lies between 0.99 AU (92 million mi, 148 million km) and 1.70 AU (158 million mi, 254 million km) from the Sun. Since the Earth orbits the Sun at an average distance of one AU, this puts us at the very edge of the habitable zone.
This may seem like a good argument for moving to Mars, which has an average distance from the Sun of 1.52 AU, but the team is careful to point out that their model doesn't take into account feedback from clouds, which reflect radiation away from the Earth and stabilize the climate.
According to the team, the model can be used to investigate the over 2,000 potential systems found by the NASA Kepler mission. It could also help the Penn States Habitable Zone Planet Finder (a spectrograph designed to seek water-sustaining planets) as well as NASA's proposed Terrestrial Planet Finder telescope network.
A paper describing the team's results has been accepted for publication in the Astrophysical Journal, but a pre-publication copy is available for viewing (PDF).
Source: Penn State

Prvo sam pomislio da bi ovo više pasovalo u "Gde bi trebalo poslati SF ekspedicije", a onda sam ustanovio da taj topik baš i ne ide u DELA STRANIH AUTORA. Na kraju, ispostavilo se da se još nekoliko topika na forumu bavi istom ili sličnom materijom u odeljku NAUKA I KVAZINAUKA. Bože, kakav haos na ovom forumu!

 


BEOGRAD - Srpski naučnici Milovan Šuvakov i Veljko Dmitrašinović, sa Univerziteta u Beogradu uspeli su da pronađu nova rešenja apstraktne naučne zagonetke koja je naučnike noćima držala budnim - može li se predviteti kako će tri objekta orbitirati jedan oko drugog na periodičan način.

U prvih 300 godina otkako je "problem tri tela" definisan, samo su tri familije rešenja otkrivene. Nedavno, dva domaća fizičara su otkrila još 13 novih familija. Ovo je pravi podvig u matematičkoj fizici koji bi mogao da značajno pomogne astrofizičarima da razumeju nove planetarne sisteme.

Otkriće ovih novih rešenja ostavilo je naučnike širom sveta zapanjenima i oduševljenim.

"Obožavam ovakve stvari", kaže Robert Vanderbei, matematičar sa Univerziteta Prinston koji nije bio umešan u rad na ovom projektu. On dodaje da je proveo celu noć razmišljajući o ovim rezultatima.

Problem tri tela potiče iz 1680. ih godina. Isak Njutn je već uveliko pokazao da njegov novi zakon gravitacije uvek može da predvidi orbite dva tela u gravitacionom polju – kao što je sistem koji se sastoji od zvezde i planete – sa apsolutnom preciznošću. Orbite u ovom slučaju su uvek elipse. Međutim, Njutn nije bio u stanju da dođe do sličnih rešenja za slučaj u kom tri tela orbitiraju jedna oko drugih. Dva veka su naučnici isprobavali različite pristupe, sve dok nemački matematičar Hajnrik Bruns nije ukazao da je potraga za opštim rešenjem problema tri tela uzaludna i da su samo specijalni slučajevi mogući za rešavanje. U opštem slučaju, poznato je da je kretanje tri tela neponavljajuće.

Ipak, specijalne, periodične slučajeve bilo je teško pronaći. Slavni matematičari Lagranž i Ojler su pronašli neka od rešenja u XVIII veku, ali novih otkrića na ovu temu nije bilo sve do sedamdesetih godina XX veka i razvoja modernog računarstva, kada su američki matematičar Rodžer Bruk i francuski astronom Mihel Enon uspeli da otkriju još. Do sada, specijalni slučajevi su bili podeljeni u tri familije: Lagranž-Ojlerova familija, Bruk-Enonova familija i familija oblika osmice, od kojih je poslednja otkrivena 1993. godine od strane fizičara Kristofera Mura sa Instituta Santa Fe.

Familija oblika osmice se zove tako zato što opisuje tri tela koja prate jedno drugo po orbitama u obliku broja osam. Lagranž-Ojlerova rešenja su jednostavnija i predstavljaju tri tela podjednako udaljena jedna od drugih koja se kreću po kružnici – poput vrteške. Bruk-Enonova familija je najsloženija: dve tela se kreću napred i nazad unutra dok treće telo orbitira okolo spolja.

Otkriće čak 13 novih familija, zaslugama fizičara Milovana Šuvakova i Veljka Dmitrašinovića sa Univerziteta u Beogradu, čini da sada ukupan broj familija specijalnih slučajeva problema tri tela iznosi 16.

"Rezultati su prelepi i prelepo su predstavljeni", kaže Ričard Montgomeri, matemaričar na Univerzitetu Kalifornije, Santa Kruz, koji nije bio umešan u otkriće.

Pronalaženje bilo kog od rešenja ima zastrašujuće nepovoljne izglede. Tri tela u prostoru se mogu postaviti na bezbroj načina. Nekako, treba pronaći početne uslove (početne pozicije i brzine) koji bi nakon određenog vremena doveli ova tela ponovo u te iste pozicije sa istim uslovima, kako bi cela ova "igra" mogla da se ponovlja u nedogled. Na osnovu rada koji je objavljen u časopisu Fizikal rivju leters, metod Šuvakova i Dmitrašinovića podrazumeva da se započne sa postojećim rešenjem u računarskoj simulaciji, a onda da se štimuju početni uslovi sve dok se ne dobije novi tip orbite.

"Ono što smo uradili je najjednostavnija stvar koju bi iko zamislio", kaže Dmitrašinović.

"Bili smo šokirani kada smo došli do novih rešenja, a bili smo još više šokirani kada smo saznali da sve ovo nije bilo prethodno otkriveno."

Suočeni sa impozantnim brojem novih rešenja, beogradski fizičari su uveli i novi klasifikacioni sistem. Oni su upotrebili apstraktni prostor nazvan "sfera oblika" koji opisuje oblik orbita pomoću međusobnih udaljenosti objekata. Tri tačke na ekvatoru sfere koje označavaju gde bi se dva tela sudarila, zajedno sa zatvorenom linijom na sferi koja ne prolazi kroz pomenute tačke, mapiraju koliko tela mogu da se približe jedna drugom. Najjednostavnije rešenje na sferi oblika je iz Lagranž-Ojlerove familije. To je samo jedna tačka, što u stvarnom prostoru predstavlja tri tela koja održavaju konstantnu i jednaku međusobnu udaljenost dok orbitiraju po kružnici.

Druga rešenja su mnogo intrigantnija. Jedno od novih rešenja, nazvano "predivo", izgleda kao klupko na sferi oblika, dok orbite ovog rešenja u stvarnom prostoru izgledaju još složenije – kao velika hrpa špageta. Sva ova rešenja mogu se pogledati OVDE.

Šuvakov i Dmitrašinović su podelili sve orbite, uključujući i prethodno poznate, u 16 familija na osnovu figura koje formiraju na sferi oblika. Ove familije su sortirali u četiri klase na osnovu simetrije i drugih karakteristika oblika, gde prva klasa sadrži sva prethodno otkrivena rešenja.

Sledeći korak beogradskih fizičara je da vide koliko je od njihovih novih rešenja stabilno – koliko će rešenja ostati na orbiti i u slučaju malih perturbacija. Ako su neka od rešenja stabilna, to znači da postoji dobra šansa da se pronađu i u stvarnosti. Trenutno, jedino opšteprihvaćeno rešenje problema tri tela posmatrano u svemiru je sistem koji čine Sunce, Jupiter i jedan od obližnjih asteroida iz grupe Trojanaca, koji orbitiraju u stilu Lagranž-Ojlerove kružnice. No, ukoliko budemo posmatrali dovoljno egzoplanetarnih sistema, postoji verovatnoća da ćemo videti neka nova, kompleksnija rešenja takođe – poput Sunčevog sistema koje izgleda kao hrpa špageta.

"Posmatračka astronomija se razvija jako ubrzano", ističe Dmitrašinović, ali i dodaje da će detektovanje nekog od ovih rešenja u svemiru još neko vreme biti vrlo teško.
Kurir         

Zanimljivo. I ova nova klasifikacija im je dobra.

Ovaj Šuvakov će sad možda morati da malo uozbilji svoj sajt, http://suki.ipb.ac.rs/

Quote from: mac on 11-03-2013, 12:38:05
http://suki.ipb.ac.rs/

znači, 2Up3R

Ne znam gde drugo ovo da stavim. Nil deGras Tajson je poklonio svoju naučničku pažnju filmu Gravitacija, jer film to zaslužuje. Prvo je gledao film i oduševio se. Onda je na Tviteru naveo neke netačnosti u filmu. Mediji su reagovali kako eto NDGT ocrnjuje film, pa je morao čovek da reaguje navodeći i neke detalje koji su verno prikazani. Na primer orbite teleskopa Habl i Međunarodne svemirske stanice su devedesetak minuta, kao što se i potencira u filmu.

E sad, šta je problem? Svemirski krš koji urniše sve na svom putu takođe orbitira (i uništava) u periodi od tih 90 minuta, ali se kreće u suprotnom smeru od svega ostalog u filmu. Posledica? Krš i sve ostalo u filmu će se sretati na svakih 45 minuta, a ne 90 kao što film prikazuje. Neko treba da javi Tajsonu, da ne živi čovek u neznanju...

Nastanjiva zona je proširena novim modelom. Procenjeni broj planeta u našoj galaksiji koje mogu da podrže život povećao se za nekih 1,5 milijardi. Takođe, dobili smo više vremena na Zemlji pre nego što Sunce postane prevruće za tečnu vodu (temperatura vremenom raste na zvezdama).

http://www.space.com/23921-habitable-zone-exoplanets-sunlike-stars.html
http://www.popularmechanics.com/science/space/deep/the-goldilocks-zone-for-planets-is-growing-16256444

Is Earth Weighed Down By Dark Matter?

Quote
Earth may have a dark-matter corset weighing it down... or that might just be a shadow.

There may be a giant ring of dark matter invisibly encircling the Earth, increasing its mass and pulling much harder on orbiting satellites than anything invisible should pull, according to preliminary research from a scientist specializing the physics of GPS signaling and satellite engineering.

The dark-matter belt around the Earth could represent the beginning of a radically new understanding of how dark matter works and how it affects the human universe, or it could be something perfectly valid but less exciting despite having been written up by New Scientist and spreading to the rest of the geek universe on the basis of a single oral presentation of preliminary research at a meeting of the American Geophysical Union in December.

The presentation came from telecom- and GPS satellite expert Ben Harris, an assistant professor of mechanical and aerospace engineering at the University of Texas- Arlington, who based his conclusion on nine months' worth of data that could indicate Earth's gravity was pulling harder on its ring of geostationary GPS satellites than the accepted mass of the Earth would normally allow.

Since planets can't gain weight over the holidays, Harris' conclusion was that something else was adding to the mass and gravitational power of Earth – something that would have to be pretty massive but almost completely undetectable, which would sound crazy if predominant theories about the composition of the universe didn't assume 80 percent of it was made up of invisible dark matter.

Harris calculated that the increase in gravity could have come from dark matter, but would have had to be an unexpectedly thick collection of it – one ringing the earth in a band 120 miles thick and 45,000 miles wide.

Harris, an expert in Global Positioning Systems, GPS networks, spacecraft systems engineering and founder of the open-source GPS software project GPS ToolKit, wasn't looking for dark matter specifically, but was trying to explain observations that suggested the Juno space probe NASA launched in August seemed to be going faster than it should have while taking a loop around the Earth to pick up a little speed for its trip to Jupiter.

The probe's unexpected extra bit of speed, other researchers suggested, could have been caused by something different about Earth's gravity, though what that could have been wasn't clear.

One possibility was that the 1964 calculation by the venerable International Astronomical Union underestimated the Earth's mass –and therefore its gravitational pull – causing NASA scientists to underestimate the speed the Juno probe would build up running "downhill" into Earth's gravity well during its final fly-by.

In an analysis published in 2009, Institute for Advanced Study researcher Stephen Adler suggested the reason for the anomaly could have been that the density of dark matter within the Solar System – and around the Earth in particular – could be much higher than astrophysicists had assumed.

Dark matter – invisible and so-far almost undetectable – was invented to try to explain why the universe does seem to be expanding from a single point as Big Bang theory predicts, but not nearly as fast as it should.

Galaxies, stars and other matter should only crawl away from each other at current speeds if there were a lot more gravity holding them back than there would be if the matter we could see were all the matter in the universe. Making the math work – getting it to agree with what the universe had already decided to do – meant bumping up the guesstimated weight of the universe by 80 percent, with nothing to explain what all that mass actually was. Dark matter is widely accepted as real among physicists, but is still more a "mystery filler" substance than an actual, explainable phenomenon.

Unlike most research about dark matter, Adler's 2008 analysis tried to pin blame for a specific micro-event on a massive, invisible force whose invisibility shows our inability to see the answer to a question we can't quite understand, or could be a fantasy created to make the math work until someone can put a finger on a more obvious and simple mistake.

One anomalous speed reading during a single flyby isn't much to hang a major proof on, however.

A dense ring of closely watched, constantly managed spacecraft in a sphere covering almost every inch of the Earth make a decent set of measurement tools. Unlike wide-orbiting, long-distance probes, GPS satellites fly in tight, precisely ordered and measured orbits that are constantly measured and adjusted by ground crews to keep each in exactly the right place to let GPS systems on the ground get consistent calculations of their own locations.

Harris took nine months of data from the U.S. network of GPS satellites, the Russian GLONASS GPS network and European Galileo satellites and started looking for differences between what the Earth's pull actually was compared to what it was supposed to be.

"The nice thing about GPS satellites is that we know their orbits really, really well," he told New Scientist. which posted a story Jan. 2 about his talk in mid-December.

Harris, who made an oral presentation of his findings but had no paper showing the data and calculations for other scientists to vet, and admitted his calculations were preliminary and presentation incomplete.

He hadn't calculated the effect of relativity on the orbits of the satellites for example, he warned New Scientist. He also hadn't yet accounted for the gravitational pull of the sun and moon or other possible influences.

Other data presented at the same meeting suggested the Juno probe was not, in fact, speeding when it passed by the Earth which, if true, would have made Harris' conclusion more tentative.

Harris concluded that the mass of Earth is between .005 percent and .008 percent higher than the figure that had been accepted almost universally since the IAU calculated it 50 years ago.

It's not like discovering an invisible new moon, but is still a pretty significant mistake, if that's what it was.

Not everyone agrees the mistake is in the IAU's figures, or even that Harris has presented enough information to know anything new about either dark matter or the Earth.

Making elaborate claims in oral presentations, without nailing down all the variables that could keep a set of results from being twisted into something more interesting than the truth is a red flag for any scientific presentation, let alone one making audacious claims about the way dark matter behaves or weight of the Earth, according to an exasperated counterargument from Matthew R. Francis, who earned a Ph.D. in physics and astronomy from Rutgers in 2005, held visiting and assistant professorships at several Northeastern universities and whose science writing has appeared in Ars Technica, The New Yorker, Nautilus, BBC Future and others including his own science blog at Galileo's Pendulum.

Dark matter might clump up around Earth as Harris suggested, but only if its particles pull more strongly on each other than most physicists expect. If they do, and if it has gathered in unlikely density around the Earth, it could have a measurable gravitational effect, but even the mass of the sun hasn't attracted dense, powerful clumps of dark matter, at least not that anyone has discovered, Francis wrote.

Prevailing theories about dark matter paint is as being much more evenly distributed throughout the galaxy, at densities equivalent to about 600 electrons within the area of a cube a centimeter on each side. In human terms that's something lower than undetectable, not something likely to create more pull on a satellite than anyone had previously found or failed to explain more simply.

Dark matter is not space dirt; it hardly interacts with "normal" matter at all.

Particles of dark matter, like Higgs Bosons, neutrinos and other particles that are difficult for humans even to detect, pass straight through each of us all the time, though "whether you find that creepy or not depends on your mindset" and how many are doing it at an one time depends on what dark matter will actually turn out to be.

"To dark matter, you're basically transparent," Francis wrote.

Francis' Jan. 2 blog entry carries the tag "debunkery," but he doesn't say Harris' conclusions are wrong, criticize his research methods or even accuse Harris of anything unsavory.

He does complain that Harris presented his conclusions and got publicity from New Scientist for them without having passed through the gauntlet of skepticism and peer review designed to filter most of the mistakes out of new research before it's published, with its data and methodology exposed so the rest of its faults can be pummeled away.

Conferences like the one at which Harris spoke are "good opportunities to present ideas that might or might not be publishable in journals," Francis wrote.

"Not publishable" can mean good science that has not yet been sufficiently vetted but ultimately will be, and complete quackery, though Francis doesn't even address which Harris' work might be.

The problem isn't the quality of the work, or its conclusions. The problem is that it was presented in too informal a way for other scientists to judge its quality, given more exposure by the New Scientist writeup and went proto-viral through the geekosphere as it was picked up writers and editors [ahem] who recognized the potential impact of Harris' results without looking hard enough at the data supporting his conclusions.

"I've seen (and even given) talks based on preliminary research that aren't ready yet, and I suspect this talk fell into that category," Francis wrote. "When Harris has taken general relativity and the effects of the Sun and Moon into account and if he still sees this phenomenon, then we might have something to talk about."

Francis added a sentence concluding that dark matter does not play a role in the motion of GPS satellites, but I left that out in deference to his concern about accuracy. Even if every word Harris said was wrong, it would only mean we have no idea whether dark matter can affect satellites, any more than we would know whether it likes to clump, gather in halos around tiny gravity wells or whether it resents being called dark and mysterious just because one planet's biological infection can't see well enough to detect 80 percent of the universe.

Better to just skip that discussion altogether.

Takođe:
   Stellar Trio Could Put Einstein's Theory of Gravity to the Test

QuoteIn a cosmic coup, astronomers have found a celestial beacon known as a pulsar in orbit with not one, but two other stars. The first-of-its-kind trio could soon be used to put Einstein's theory of gravity, or general relativity, to an unprecedented test. "It's a wonderful laboratory that nature has given us," says Paulo Freire, a radio astronomer at the Max Planck Institute for Radio Astronomy in Bonn, Germany, who was not involved in the work. "It's almost made to order."
A pulsar consists of a neutron star, the leftover core of a massive star that has blown up in a supernova explosion. The core's own gravity squeezes it so intensely that the atomic nuclei meld into a single sphere of neutrons. The spinning neutron star also shines out a beam of radio waves that sweeps the sky just as the light beam from a lighthouse sweeps the sea. In fact, pulsars flash so regularly that they make natural timepieces whose ticking can be as steady as that of an atomic clock.
The incredible regularity makes it possible to determine whether the pulsar is in orbit with another object, as roughly 80% of the more than 300 fast-spinning "millisecond" pulsars are known to be. As the pulsar and its companion orbit each other, the distance between the pulsar and Earth varies slightly, so that it takes more or less time for the pulses of radio waves to reach Earth. As a result, the frequency of pulsing speeds up and slows down in a telltale cycle.
But such a simple scenario couldn't explain the peculiar warbles in the frequency of pulsar PSR J0337+1715, which Scott Ransom, an astronomer at the National Radio Astronomy Observatory in Charlottesville, Virginia, and colleagues discovered in 2007 with the Robert C. Byrd Green Bank Telescope in West Virginia. Training other radio telescopes on the object, Ransom and colleagues kept it under near-constant surveillance for a year and a half. Eventually, Anne Archibald, a graduate student at McGill University in Montreal, Canada, figured out exactly what's going on.
The pulsar, which has 1.4 times the sun's mass and spins 366 times a second, is in a tight orbit lasting 1.6 days with a white dwarf star only 20% as massive as the sun. A second white dwarf that weighs 41% as much as the sun orbits the inner pair every 327 days, as Ransom and colleagues report online today in Nature. "We think that there are not more than 100 of these [trios] in our galaxy," Ransom says. "They really are one-in-a-billion objects."
The distinctive new system opens the way for testing a concept behind general relativity known as the equivalence principle, which relates two different conceptions of mass. An object's inertial mass quantifies how it resists pushing or pulling: It's easier to start a stroller rolling than a car because the stroller has less inertial mass. A thing's gravitational mass determines how much a gravitational field pulls on it: A barbell is heavier than a feather because it has more gravitational mass.
The simplest version of the equivalence principle says inertial mass and gravitational mass are equal. It explains why ordinary objects like baseballs and bricks fall to Earth at the same rate regardless of their mass—as legend claims Galileo showed by dropping heavier and lighter balls from the Leaning Tower of Pisa.
The strong equivalence principle takes things an important step further. According to Einstein's famous equation, E = mc², energy equals mass. So an object or system's mass can be generated by the energy in the gravitational fields within the system itself. The strong equivalence principle states that even if one includes mass generated through such "self-gravitation," gravitational and inertial mass are still equal. The principle holds in Einstein's theory of general relativity but typically does not hold in alternative theories, says Thibault Damour, a theoretical physicist at the Institute for Advanced Scientific Studies in Bures-sur-Yvette, France. So poking a pin in the principle would prove that general relativity is not the final word on gravity.
Researchers have already tried to test the strong equivalence principle. Since the 1970s, some have compared how the moon and Earth orbit in the gravitational field of the sun. More recently, others have analyzed the motion of pulsar–white dwarf pairs in the gravitational field of the galaxy. But those studies have been limited, Damour says. Earth's self-gravitation accounts for just a billionth of its mass. In pulsar studies, the galaxy's gravity is very weak. So the strong equivalence principle has been tested only to a precision of parts per thousand.
The new pulsar system opens the way to a much more stringent test by combining the strengths of the two previous methods. The self-gravitation of the pulsar accounts for roughly 10% of its mass, in contrast to less than 0.001% for the inner white dwarf. At the same time, both move in the gravitational field of the outer white dwarf, which is much stronger than the field of the galaxy. By tracking the system's evolution, Ransom and colleagues should be able to tell whether either the inner white dwarf or the pulsar falls faster toward the outer white dwarf and test strong equivalence about 100 times as precisely as before, Damour says.
So will strong equivalence principle be found wanting? "I would rather expect to get a better limit" on possible violations, Damour says. "But I'm open-minded. It would be great to get a violation." Freire says a violation would be "a complete revolution."
Researchers may not have to wait long, Ransom says. His team should be able to test the principle within a year.
   

Nećemo otvarati nove topike samo zato što je neko konačno uspeo da sintetiše i stabilizuje (well, sort of) antivodonik!!!!!!!


Antimatter experiment produces first beam of antihydrogen

Quote
The ASACUSA experiment at CERN has succeeded for the first time in producing a beam of antihydrogen atoms. In a paper published today in Nature Communications, the ASACUSA collaboration reports the unambiguous detection of 80 antihydrogen atoms 2.7 metres downstream of their production, where the perturbing influence of the magnetic fields used initially to produce the antiatoms is small. This result is a significant step towards precise hyperfine spectroscopy of antihydrogen atoms.
Primordial antimatter has so far never been observed in the universe, and its absence remains a major scientific enigma. Nevertheless, it is possible to produce significant amounts of antihydrogen in experiments at CERN by mixing antielectrons (positrons) and low energy antiprotons produced by the Antiproton Decelerator.
The spectra of hydrogen and antihydrogen are predicted to be identical, so any tiny difference between them would immediately open a window to new physics, and could help in solving the antimatter mystery. With its single proton accompanied by just one electron, hydrogen is the simplest existing atom, and one of the most precisely investigated and best understood systems in modern physics. Thus comparisons of hydrogen and antihydrogen atoms constitute one of the best ways to perform highly precise tests of matter/antimatter symmetry.
Matter and antimatter annihilate immediately when they meet, so aside from creating antihydrogen, one of the key challenges for physicists is to keep antiatoms away from ordinary matter. To do so, experiments take advantage of antihydrogen's magnetic properties (which are similar to hydrogen's) and use very strong non-uniform magnetic fields to trap antiatoms long enough to study them. However, the strong magnetic field gradients degrade the spectroscopic properties of the (anti)atoms. To allow for clean high-resolution spectroscopy, the ASACUSA collaboration developed an innovative set-up to transfer antihydrogen atoms to a region where they can be studied in flight, far from the strong magnetic field.
"Antihydrogen atoms having no charge, it was a big challenge to transport them from their trap. Our results are very promising for high-precision studies of antihydrogen atoms, particularly the hyperfine structure, one of the two best known spectroscopic properties of hydrogen. Its measurement in antihydrogen will allow the most sensitive test of matter/antimatter symmetry. We are looking forward to restarting this summer with an even more improved set-up," says Yasunori Yamazaki of RIKEN, Japan, a team leader of the ASACUSA collaboration. The next step for the ASACUSA experiment will be to optimize the intensity and kinetic energy of antihydrogen beams, and to understand better their quantum state.
Progress with antimatter experiments at CERN has been accelerating in recent years. In 2011, the ALPHA experiment announced trapping of antihydrogen atoms for 1000 seconds and reported observation of hyperfine transitions of trapped antiatoms in 2012. In 2013, the ATRAP experiment announced the first direct measurement of the antiproton's magnetic moment with a fractional precision of 4.4 parts in a million.
Read the paper: "A source of antihydrogen for in-flight hyperfine spectroscopy" – Nature Communications
 

   
• Français

Posted by Cian O'Luanaigh on 21 Jan 2014. Last updated 21 Jan 2014, 17.36.   
Topic Antimatter

   
• The matter-antimatter asymmetry problem

Sigurno ste se nekad upitali da li neka planeta može da ima oblik torusa (krofne). Gle čuda, može:

http://io9.com/what-would-the-earth-be-like-if-it-was-the-shape-of-a-d-1515700296

A, jel' može kao ćevap? Neverending krk&look.

Torus je stabilan, treba samo da se obrće odgovarajućom brzinom. Planeta bi mogla da bude samo od vode, i opet bi se nekako držala. Ćevap bi se, s druge strane, urušio u ćuftu.

    Pluto's Moons Are Even Weirder Than Thought

Quote
Pluto's moons are even stranger and more intriguing than scientists imagined, a new study reveals.

The Pluto system consists of four tiny satellites — Nix, Hydra, Kerberos and Styx — orbiting a "binary planet" comprised of Pluto and its largest moon Charon, which, at 750 miles (1,207 kilometers) in diameter, is nearly half as wide as the dwarf planet itself.

This binary setup has profoundly influenced the orbits of the four small moons, injecting chaos into their movements — as depicted in a newly released animation of tumbling Nix — in ways not fully appreciated until now, the study suggests. [Photos of Pluto and Its Moons]
"It's a very strange place to live in if you are orbiting a binary planet," lead author Mark Showalter, of the SETI (Search for Extraterrestrial Intelligence) Institute in Mountain View, California, told Space.com. Brightness and size
Showalter and co-author Douglas Hamilton, of the University of Maryland, analyzed images of the Pluto system taken by NASA's Hubble Space Telescope between 2005 and 2012. (During this period, the observatory discovered all four of the dwarf planet's tiny known moons; Showalter led the teams that detected Kerberos and Styx.)

The two researchers used these photos — which captured brightness variations of the moons over time — and computer models to characterize the four small satellites and their orbits in unprecedented detail.

For example, Showalter and Hamilton derived new brightness and size estimates for the moons. They found that Nix and Hydra are likely about as bright as Charon, which reflects roughly 40 percent of the light that hits it.

Before the new study, "we didn't really know how big Nix and Hydra were, because we didn't know how bright they were," Showalter said. "And now, based on our analysis, we actually do pretty well know how big and how bright they are, so there are a lot of uncertainties about the properties of Nix and Hydra that have gone away now."
The Hubble images suggest that Hydra is around 28.2 miles (45.4 km) across, while Nix has a diameter of 24.6 miles (39.6 km) or so. Kerberos and Styx, meanwhile, are probably about 15.4 miles (24.8 km) and 4.2 miles (6.8 km) wide. (These latter two moons are tougher to characterize, because they are fainter than Nix and Hydra.)

These diameter estimates assume a spherical shape for the moons, which is likely not the reality; most if not all of the four tiny satellites are probably ellipsoidal, researchers said.

The duo's analysis also suggests that Kerberos is much darker than its fellow satellites, with a reflectivity of just 4 percent. Whereas Nix and Hydra are basically "dirty snowballs" in terms of reflectivity, "Kerberos is a charcoal briquet," Showalter said. [Pluto's 5 Moons Explained (Infographic)]

This result "took us completely by surprise, because everybody has been assuming all along that the moons would be pretty similar," he added. "They all probably formed at the same time; they all are made of the same stuff."

Astronomers think Pluto's four small moons were formed from the debris scattered by a long-ago giant impact between a proto-Pluto object and a proto-Charon. Perhaps the proto-Charon was a very dark body, and Kerberos is a relatively pristine piece of this original impactor, Showalter said, though he stressed that this idea is mere speculation.   Resonance and chaos
Showalter and Hamilton also determined that Styx, Nix and Hydra are linked by a "resonance," a sort of gravitational sweet spot in which orbits of multiple celestial bodies are related by a ratio of two whole numbers. A similar three-body resonance is found among the Jupiter moons Io, Europa and Ganymede, the researchers said.

"The resonant relationship between Nix, Styx and Hydra makes their orbits more regular and predictable, which prevents them from crashing into one another," Hamilton said in a statement. "This is one reason why tiny Pluto is able to have so many moons."

But there is also quite a bit of chaos in the Pluto system, imparted by the complex and shifting gravitational field of the Pluto-Charon binary.
For instance, Showalter and Hamilton found that Nix and Hydra exhibit chaotic rather than synchronous rotation, meaning they don't always keep the same side facing Pluto-Charon — and that it's very tough to predict their rotational movement. (Nearly every other moon in the solar system, including Earth's, is a synchronous rotator.)

"If you lived on Nix, you would not know if the sun is coming up tomorrow; it is that extreme," Showalter said, adding that models suggest that Styx and Kerberos are chaotic rotators as well. "You'd have days where the sun rises in the east and sets in the north."

Such findings could help researchers better understand the many alien planets that orbit binary stars, researchers said.

"We are learning that chaos may be a common trait of binary systems," Hamilton said. "It might even have consequences for life on planets orbiting binary stars."  New Horizons and beyond
The new study was published online in the journal Nature today (June 3), just six weeks ahead of the first-ever Pluto flyby. On July 14, NASA's New Horizons spacecraft will zoom within 7,800 miles (12,500 km) of the dwarf planet's surface.

New Horizons should get good looks at the surfaces of Nix and Hydra, and the probe's observations will likely reveal how dark Kerberos is, Showalter said.

Data from the flyby, as well as continued long-term monitoring by Hubble and NASA's James Webb Space Telescope, which is scheduled to launch in 2018, could end up bringing Pluto's moons into sharp focus, he added.

"We've got pieces to start fitting together, and maybe eventually out of this we'll get a whole formation scenario for the [Pluto] system," Showalter said.

Na linku imaju i slike i video.

Itan Sigel spekuliše:

Kolonija treba da bude isplativa, ili ekonomski ili tako što će oni koji uspostave koloniju steći neka nova saznanja. Mesec nudi par dobrih razloga za kolonizaciju (Helijum-3, materijal za neku masovnu proizvodnju satelita oko Zemlje), ali na Veneri trenutno nema ništa interesantno.

Opet Itan:
Why Is Our Solar System Missing The Universe's Most Common Planet?

The New, Nerdy Mythology of Pluto's Place Names

Quote
Once you have pictures of a never-before-seen-up-close almost-planet, you have to start naming what you see. And according to an image of  from the New Horizons press room that our correspondent Nick Stockton tweeted earlier today, the Plutonians have started naming their surroundings...informally. 

The names are all related to various mythologies of the underworld, appropriately enough. They also suggest that some of these researchers are pretty darn nerdy—though some of the names seem to have come from  during New Horizons' flight.

Like, for example, "Cthulu," the name of an elder god from the fiction of HP Lovecraft. Or what about "Balrog," the name of the monster that seemingly killed Gandalf the Grey in the Lord of the Rings trilogy? Meng-p'o is the Buddhist goddess of forgetfulness and amnesia—she lives in the underworld. Hun-Came and Vucub-Came are Mayan death gods.

We thought at first that Krun was a reference to a Non-Player Character from the hellfire peninsula in World of Worldcraft, but he's actually one of five lords of the underworld for the Mandaeans, an ancient religion from the Iraq-Iran region. (His nickname is "Mountain-of-Flesh.") Ala is an underworld and harvest goddess of the Ibo people of eastern Nigeria.

Pluto might not technically be a planet, but it has some great place-names.

NASA just found something big hiding out behind Pluto

Quote

NASA and the team behind its New Horizons spacecraft announced today that Pluto — the dwarf planet — has a giant tail.

It's not a physical tail like a dog's, of course, but rather a frigid cloud of ionized gases trailing an estimated 48,000 to 68,000 miles behind Pluto, according to a NASA press release.

This giant tail is actually part of Pluto's atmosphere. Except that the bits of atmosphere are being stripped away by solar wind, a torrent of electrically charged particles that constantly pours out of the sun in all directions.

"We see the atmosphere way far out," Randy Gladstone, a New Horizons coinvestigator at Southwest Research Institute in San Antonio, said during a NASA press conference on Friday. "We see it from the ground out to 1,000 miles above the surface."

Because Pluto is such a tiny planet — it's a fraction of a percent as massive as the Earth — its atmosphere escapes directly into space, Gladstone said.

Gladstone and others discovered the tail after examining data from the Solar Wind Around Pluto (SWAP) instrument on the New Horizons spacecraft. The device found an anomaly in the solar wind around the dwarf planet: A depression composed of nitrogen ions. This depression is the tail, and it extends an unknown length behind the planet.

"We have actually flown through this [tail]," Fran Bagenal, a New Horizons coinvestigator from the University of Colorado at Boulder, said during the press conference.

Ionized gas forms when a bunch of energy pummels atmospheric atoms and molecules. This bombardment pops electrons off the atmospheric gas particles, allowing their electrons to freely circulate. The end result is plasma: A fourth state of matter after solids, liquids, and gases.

As far as we know, plasma is the most common state of matter in the universe. There's simply a lot of energy pouring out of stars, and a lot of gas in space to form plasma. So while it might seem surprising, plasma tails like Pluto's aren't new. They even exist behind other planets in the solar system, including Venus and Mars.

The team still hasn't determined the precise shape of Pluto's newly discovered tail. They also don't know exactly how the was formed.

So NASA is anxiously waiting for New Horizons to beam back more data. By August the team hopes to calculate how fast Pluto is losing its atmosphere to space — and, likewise, how quickly the icy world is shrinking.

NOW WATCH: Scientists just discovered 11,000-foot ice mountains, geysers and volcanoes on Pluto

Universe Is Dying, Galactic Survey Shows

Quote
A study of more than 200,000 galaxies, encompassing wavelengths of light from the far ultraviolet to infrared, shows that the universe is producing half as much energy as it did 2 billion years ago and continues to fade.
"Newer galaxies are simply putting out less energy than galaxies did in the past," astronomer Mehmet Alpaslan, with NASA's Ames Research Center in Mountain View, Calif., told Discovery News.Older stars are fading out faster than new stars are forming, a trend that eventually will leave the universe a cold and lonely place. "At some point, all matter will eventually decay. We're observing the lights slowly shutting down," Alpasian said.
"The timeline for all this to come to pass is very long, hundreds of trillions of years," he added.
The study, released Monday at the International Astronomical Union conference in Hawaii, culminates a seven-year, international effort to measure both the distances and energy output of more than 200,000 galaxies.
Seven observatories, including Europe's Visible and Infrared Survey Telescope for Astronomy (VISTA) and its VLT Survey Telescope, both at the Paranal Observatory in Chile, contributed to the study. Other data came from NASA's Wide-field Infrared Survey Explorer (WISE) and its now-defunct Galaxy Evolution Explorer (GALEX) space telescopes, and European Space Agency's retired Herschel space telescope.


"GAMA is the first survey to study a large number of galaxies and map the energy outputs over the range where most of the energy comes out," lead scientist Simon Driver, with the University of Western Australia, wrote in an email to Discovery News.
Scientists have known since the late 1990s that the universe is slowly fading, but the GAMA study is the first to measure galaxies' radiation across the spectrum. Measurements were made at 21 wavelengths, ranging from the far ultraviolet to the infrared.
"You're probing a lot of different kinds of physics when you look at a lot of different energy," Alpaslan said. "Having the homogeneous data set makes it a lot easier to fully understand what is going on in a galaxy across all these different kinds of physics."
The decline in galaxies' energy output coincides with the universe's ever-increasing rate of expansion, which is due to a mysterious, anti-gravity force referred to as dark energy.


Astronomers now plan to use the GAMA data for a variety of studies, such as understanding how different types of stars form and evolve in different kinds of environments; the rates at which galaxies are merging; and how those merges impact the galaxies' evolution.
"We're phasing toward doing more science with the data, rather than just analyzing," Alpaslan said. "We've surveyed a large enough region for this to be representative."
The GAMA team's research has been submitted for publication in the Monthly Notices of the Royal Astronomical Society.

Quote from: Meho Krljic on 12-08-2015, 10:18:49
Universe Is Dying, Galactic Survey Shows

Quote
A study of more than 200,000 galaxies, encompassing wavelengths of light from the far ultraviolet to infrared, shows that the universe is producing half as much energy as it did 2 billion years ago and continues to fade.
"Newer galaxies are simply putting out less energy than galaxies did in the past," astronomer Mehmet Alpaslan, with NASA's Ames Research Center in Mountain View, Calif., told Discovery News.Older stars are fading out faster than new stars are forming, a trend that eventually will leave the universe a cold and lonely place. "At some point, all matter will eventually decay. We're observing the lights slowly shutting down," Alpasian said.
"The timeline for all this to come to pass is very long, hundreds of trillions of years," he added.
The study, released Monday at the International Astronomical Union conference in Hawaii, culminates a seven-year, international effort to measure both the distances and energy output of more than 200,000 galaxies.
Seven observatories, including Europe's Visible and Infrared Survey Telescope for Astronomy (VISTA) and its VLT Survey Telescope, both at the Paranal Observatory in Chile, contributed to the study. Other data came from NASA's Wide-field Infrared Survey Explorer (WISE) and its now-defunct Galaxy Evolution Explorer (GALEX) space telescopes, and European Space Agency's retired Herschel space telescope.


"GAMA is the first survey to study a large number of galaxies and map the energy outputs over the range where most of the energy comes out," lead scientist Simon Driver, with the University of Western Australia, wrote in an email to Discovery News.
Scientists have known since the late 1990s that the universe is slowly fading, but the GAMA study is the first to measure galaxies' radiation across the spectrum. Measurements were made at 21 wavelengths, ranging from the far ultraviolet to the infrared.
"You're probing a lot of different kinds of physics when you look at a lot of different energy," Alpaslan said. "Having the homogeneous data set makes it a lot easier to fully understand what is going on in a galaxy across all these different kinds of physics."
The decline in galaxies' energy output coincides with the universe's ever-increasing rate of expansion, which is due to a mysterious, anti-gravity force referred to as dark energy.


Astronomers now plan to use the GAMA data for a variety of studies, such as understanding how different types of stars form and evolve in different kinds of environments; the rates at which galaxies are merging; and how those merges impact the galaxies' evolution.
"We're phasing toward doing more science with the data, rather than just analyzing," Alpaslan said. "We've surveyed a large enough region for this to be representative."
The GAMA team's research has been submitted for publication in the Monthly Notices of the Royal Astronomical Society.

Sveža vest, bokte, nismo pojma imali, ono jeste da je Klauzijus otkrio drugi zakon termodinamike još 1850. a Vilijam Tomson iz toga izveo ideju o toplotnoj smrti vasione sledeće godine...

Quote from: mac on 11-09-2010, 01:23:42
Sad bi bar moglo da padne više detalja o tom konkursu, ili šta li je već bio. I malo konkretnije o vašoj ideji.

Džebote, tek sam sada video Macovo pitanje od pre pet godina. I'm an idiot.

Elem, reč je bila o konkursu koji se zvao Worldbuilding (ili tako nešto) i sastojao se od faza. Prva faza je bila "izrada" naučno uverljive planete/sveta/objekta negde u svemiru. Dakle, to je mogla da bude planeta, neko veštačko telo ili šta već, ali uslov je bio da to telo bude  dovoljno veliko da bi se na njemu razvio stabilan ekosistem, pa onda i civilizacija. Druga faza je bila upravo civilizacija/kultura, ali na odabranom nebeskom telu. Dakle, svi učesnici koji prođu u drugi krug morali bi da za svoju planetu/šta već uzmu pobednika iz prvog kruga. U trećoj fazi se pišu priče, koje se odigravaju u okvirima civilizacije/kulture koja je pobedila u drugoj fazi.

Mene je moja grupa angažovala zbog civilizacijskog aspekta, ali nismo prošli ni u drugu fazu

QuoteSveža vest, bokte, nismo pojma imali, ono jeste da je Klauzijus otkrio drugi zakon termodinamike još 1850. a Vilijam Tomson iz toga izveo ideju o toplotnoj smrti vasione sledeće godine...

A Pamela Zoline potvrdila u kultnoj priči novog talasa "The Heat Death of the Universe" (vidi neki stari SIRIUS)... 

Ili vidi ovde

http://future-lives.com/wp-content/uploads/2014/09/zoline_heat-death.pdf

Naravno! Ja sam je prvi put čitala u tematu Reči posvećenom entropiji, koji je uredio Novica Petrović. Divan temat bio, i Pinčon i Balard i sve sve

Quote from: Nightflier on 12-08-2015, 17:02:33
Mene je moja grupa angažovala zbog civilizacijskog aspekta, ali nismo prošli ni u drugu fazu

Možda je problem bio to što se vaš ekosistem nije nešto bitno razlikovao od ovdašnjeg zemaljskog. Ako sam dobro razumeo vaša ideja je bila crna rupica mase Meseca koja je uvek skrivena sa druge strane vidljivog satelita, koji kruži oko planete osetno (ali ne previše) veće od Zemlje, ali sa Zemljinom gravitacijom.

Koji su rezultati konkursa? Koje ekološke ideje su prošle dalje, i šta je na kraju pobedilo? Ima li neki link?

Prestao sam da pratim negde na polovini druge faze. Na kraju su neke priče napisane i objavljene na nekoj onlajn platformi - da li Wattpadu ili tako nečemu, ali više se ne sećam.

 Has Stephen Hawking Just Solved a Huge Black-Hole Mystery?

Quote
Stephen Hawking may have just solved one of the most vexing mysteries in physics — the "information paradox."

Einstein's theory of general relativity predicts that the physical information about material gobbled up by a black hole is destroyed, but the laws of quantum mechanics stipulate that information is eternal. Therein lies the paradox.

Hawking — working with Malcolm Perry, of the University of Cambridge in England, and Harvard University's Andrew Stromberg — has come up with a possible solution: The quantum-mechanical information about infalling particles doesn't actually make it inside the black hole.

"I propose that the information is stored not in the interior of the black hole, as one might expect, but on its boundary, the event horizon," Stephen Hawking said during a talk today (Aug. 25) at the Hawking Radiation conference, which is being held at the KTH Royal Institute of Technology in Stockholm, Sweden.

The information is stored at the boundary as two-dimensional holograms known as "super translations," he explained. But you wouldn't want super translations, which were first introduced as a concept in 1962, to back up your hard drive.

"The information about ingoing particles is returned, but in a chaotic and useless form," Hawking said. "For all practical purposes, the information is lost."

Hawking also discussed black holes — whose gravitational pull is so intense that nothing, not even light, can escape once it passes the event horizon — during a lecture last night (Aug. 24) in Stockholm.

It's possible that black holes could actually be portals to other universes, he said.

"The hole would need to be large, and if it was rotating, it might have a passage to another universe. But you couldn't come back to our universe," Hawking said at the lecture, according to a KTH Royal Institute of Technology statement. "So, although I'm keen on spaceflight, I'm not going to try that."

http://youtu.be/DkRDmJpthXg

Whoa!



Researchers catch Comet Lovejoy giving away alcohol

Quote
Comet Lovejoy lived up to its name by releasing large amounts of alcohol as well as a type of sugar into space, according to new observations by an international team. The discovery marks the first time ethyl alcohol, the same type in alcoholic beverages, has been observed in a comet. The finding adds to the evidence that comets could have been a source of the complex organic molecules necessary for the emergence of life.
"We found that comet Lovejoy was releasing as much alcohol as in at least 500 bottles of wine every second during its peak activity," said Nicolas Biver of the Paris Observatory, France, lead author of a paper on the discovery published Oct. 23 in Science Advances. The team found 21 different organic molecules in gas from the comet, including ethyl alcohol and glycolaldehyde, a simple sugar.
Comets are frozen remnants from the formation of our solar system. Scientists are interested in them because they are relatively pristine and therefore hold clues to how the solar system was made. Most orbit in frigid zones far from the sun. However, occasionally, a gravitational disturbance sends a comet closer to the sun, where it heats up and releases gases, allowing scientists to determine its composition.
Comet Lovejoy (formally cataloged as C/2014 Q2) was one of the brightest and most active comets since comet Hale-Bopp in 1997. Lovejoy passed closest to the sun on January 30, 2015, when it was releasing water at the rate of 20 tons per second. The team observed the atmosphere of the comet around this time when it was brightest and most active. They observed a microwave glow from the comet using the 30-meter (almost 100-foot) diameter radio telescope at Pico Veleta in the Sierra Nevada Mountains of Spain.
Sunlight energizes molecules in the comet's atmosphere, causing them to glow at specific microwave frequencies (if microwaves were visible, different frequencies would be perceived as different colors). Each kind of molecule glows at specific, signature frequencies, allowing the team to identify it with detectors on the telescope. The advanced equipment was capable of analyzing a wide range of frequencies simultaneously, allowing the team to determine the types and amounts of many different molecules in the comet despite a short observation period.
Some researchers think that comet impacts on ancient Earth delivered a supply of organic molecules that could have assisted the origin of life. Discovery of complex organic molecules in Lovejoy and other comets gives support to this hypothesis.
"The result definitely promotes the idea the comets carry very complex chemistry," said Stefanie Milam of NASA's Goddard Space Flight Center in Greenbelt, Maryland, a co-author on the paper. "During the Late Heavy Bombardment about 3.8 billion years ago, when many comets and asteroids were blasting into Earth and we were getting our first oceans, life didn't have to start with just simple molecules like water, carbon monoxide, and nitrogen. Instead, life had something that was much more sophisticated on a molecular level. We're finding molecules with multiple carbon atoms. So now you can see where sugars start forming, as well as more complex organics such as amino acids -- the building blocks of proteins -- or nucleobases, the building blocks of DNA. These can start forming much easier than beginning with molecules with only two or three atoms."
In July, the European Space Agency reported that the Philae lander from its Rosetta spacecraft in orbit around comet 67P/Churyumov­-Gerasimenko detected 16 organic compounds as it descended toward and then bounced across the comet's surface. According to the agency, some of the compounds detected play key roles in the creation of amino acids, nucleobases, and sugars from simpler "building-block" molecules.
Astronomers think comets preserve material from the ancient cloud of gas and dust that formed the solar system. Exploding stars (supernovae) and the winds from red giant stars near the end of their lives produce vast clouds of gas and dust. Solar systems are born when shock waves from stellar winds and other nearby supernovae compress and concentrate a cloud of ejected stellar material until dense clumps of that cloud begin to collapse under their own gravity, forming a new generation of stars and planets.
These clouds contain countless dust grains. Carbon dioxide, water, and other gases form a layer of frost on the surface of these grains, just as frost forms on car windows during cold, humid nights. Radiation in space powers chemical reactions in this frost layer to produce complex organic molecules. The icy grains become incorporated into comets and asteroids, some of which impact young planets like ancient Earth, delivering the organic molecules contained within them.
"The next step is to see if the organic material being found in comets came from the primordial cloud that formed the solar system or if it was created later on, inside the protoplanetary disk that surrounded the young sun," said Dominique Bockelée-Morvan from Paris Observatory, a co-author of the paper.

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Milam was funded by a grant from the NASA Planetary Astronomy Program. The team included researchers from the Paris Observatory, CNRS (Centre National de la Recherche Scientifique, Paris), PSL Research University (Paris Sciences et Lettres, Paris), Bordeaux Observatory, France, IRAM (Institut de Radioastronomie Millimétrique, Grenoble, France) and Stockholm Observatory, Stockholm, Sweden, as well as from NASA. The 30-meter telescope used to make the team's observations is operated by IRAM, a collaboration among France, Germany, and Spain. IRAM is supported by INSU (Institut National des Sciences de l'univers)/CNRS (France), MPG (Max-Planck-Gesellschaft zur Förderung der Wissenschaften e. V.) (Germany), and IGN (Instituto Geográfico Nacional) (Spain).

I ja Love Joy i ponekad give away alcohol.

 Teza koja ima smisla:  Earth Bloomed Early: A Fermi Paradox Solution?

Quote
Our place in the universe is a conundrum — life on Earth evolved to create a technologically-savvy race that is now looking for other technologically-savvy intelligences populating our galaxy. But there's a problem; it looks like humanity is the only "intelligent" species in our little corner of the universe — what gives?

This question forms the basis of the Fermi Paradox: given the age of the universe and the apparent high probability of life evolving on other planets orbiting other stars, where are all the smart aliens?
According to a new study based on data collected by the NASA/ESA Hubble Space Telescope and NASA's Kepler Space Telescope, it might be that Earth (and all life on it) is an early bloomer. By extension, the logical progression from this new study is that we're not hearing from advanced alien civilizations because, in short, the universe hasn't had the time to spawn many more habitable worlds.

The study, which focuses purely on the likelihood of the evolution of habitable worlds (and not speculation of alien intelligence, the Fermi Paradox implication is my own), finds that when our planet was born from our young sun's protoplanetary disk some 4.6 billion years ago, it was born into an era when only "8 percent of the potentially habitable planets that will ever form in the universe existed." This means that the universe has 92 percent to go until it runs out of the necessary material to produce the stars that go on to produce planets, some of which will be small and rocky and orbit in just the right location for life (as we know it) to thrive.

"Our main motivation was understanding the Earth's place in the context of the rest of the universe," said Peter Behroozi of the Space Telescope Science Institute (STScI) in Baltimore, Md., "Compared to all the planets that will ever form in the universe, the Earth is actually quite early."

Hubble has shown astronomers that young galaxies were churning out stars at a fast rate some 10 billion years ago. However, the quantity of hydrogen and helium involved in stellar production was low compared with the amount of these star-forming gases that exist today.
"There is enough remaining material (after the Big Bang) to produce even more planets in the future, in the Milky Way and beyond," said Molly Peeples, also of STScI.

By combining this knowledge from Hubble with exoplanetary data from Kepler, the researchers were able to form a picture of the habitable planet potential of our galaxy and use it as a model for the number of other habitable worlds existing throughout the cosmos.

Since Kepler started taking data in 2009, we've been introduced to a menagerie of small rocky worlds orbiting sun-like stars. Some of these thousands of worlds orbit their stars within the habitable zone — the region surrounding a star that's not too hot and not too cold to allow liquid water to persist on its surface. By extrapolating from Kepler's comparatively small dataset, astronomers have predicted that there should be around 1 billion Earth-sized worlds orbiting within their stars' habitable zones in the Milky Way. If we consider there are 100 billion galaxies in the observable universe, there's a huge number of habitable, Earth-sized worlds throughout the cosmos.

And the universe, according to this new theoretical study, has only just started in the planetary production business. The last star isn't expected to fizzle out for another 100 trillion years (when the universe will continue toward its perpetual march to "heat death"), so there's lots of time left.
With the help of these observations, the researchers predict that Earth 2.0 (i.e. rocky planets of Earth-like dimensions orbiting within their stars' habitable zones) will most likely pop up inside giant galaxy clusters or dwarf galaxies where reservoirs of star-forming (and therefore planet-forming) gases are known to reside. Alas, the Milky Way's planet-forming days are numbered, as much of these gases have already been consumed during our galaxy's heady "starburst" days.

Noted by the researchers is that the advantage of being an "early" civilization evolving at this time of universal evolution is that we have the awesome opportunity to study the early stages of cosmic evolution, using space telescopes (such as Hubble) to see the early formation of galaxies and witness observable evidence for the Big Bang. For any future civilization in a trillion years time, the universe will look very different than it does now — fewer galaxies will be visible and the earliest evidence for the Big Bang (such as the cosmic microwave background radiation) will have further ebbed away.

It's interesting to ponder how an intelligent alien civilization will interpret a more mature, perpetually expanding universe lacking the cues to its origin that we take for granted today. Would they assume, lacking contradictory evidence, that the universe has always existed? And that just because the universe is expanding, it doesn't mean there had to be a Big Bang?
Of course, this is just a fun thought experiment; predicting the existence of a future alien intelligence, let alone how they may interpret their cosmic environment, is presumptuous at best. But it does pose an existential problem beyond the Fermi Paradox. If the Earth is an early bloomer, and humanity is one of the first intelligent civilizations to pop up in a universe of infinite possibilities, how might our civilization unfold?

Who knows, but it seems the universe has the boundless potential to form new worlds and new life (and new intelligences) that will potentially form long after humanity and life on Earth has come and gone, eventually succumbing to the inevitable death of our sun in about 5 billion years time. This study serves to remind us that our time as an intelligent life form in the universe is fleeting, and it seems many more intelligences will evolve long after we are gone.

Source: Hubblesite.org

Mystery Of Mars' Lost Atmosphere Solved At Last, Thanks To NASA's MAVEN Mission

We've found the brightest ever supernova but can't explain it

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The brightest supernova ever seen has been confirmed, but it still has astronomers puzzling over what unknown type of star could have been responsible.
Supernovas mark the violent deaths of stars that collapse on themselves and blow up. They are some of the brightest and most energetic objects in the universe.
This one, called ASASSN-15lh, is about 3.8 billion light years away, 200 times more powerful than most supernovas, and twice as bright as the previous record holder. It shines 20 times brighter than the combined output of the Milky Way's 100 billion stars, and in the last six months, it has spewed as much energy as the sun would in 10 lifetimes, says Krzysztof Stanek of the Ohio State University, co-principal investigator of the All Sky Automated Survey for SuperNovae (ASAS-SN) network that spotted the explosion.
   "This is really on steroids, and then some," he says. "If it was in our own galaxy, it would shine brighter than the full moon; there would be no night, and it would be easily seen during the day."
He spotted the outburst on 14 June while perusing telescope images over his morning coffee, and alerted the rest of the ASAS-SN team, including Subo Dong at the Kavli Institute for Astronomy and Astrophysics at Peking University. Dong quickly signalled a network of amateur astronomers who help the team confirm possible supernovae, and received some images that night.
The team suspected it was a rare "superluminous" supernova, but the 14-centimetre ASAS-SN telescopes were too small to see the details required to be sure. Bad weather and problems with instruments delayed further investigation by 10 days. Finally the Southern African Large Telescope revealed details about the star's chemical makeup when it exploded, allowing Dong to calculate its distance and confirm that the object was the brightest supernova ever recorded. It was 2 am in Beijing when Dong received these results, "but I was too excited to sleep the rest of the night", he says.


The supernova appears to be in an old, large galaxy that is bigger and brighter than the Milky Way, which is unusual because the handful of other known superluminous supernovas have been found in dim, small and young galaxies. It's also much hotter than other stellar explosions.
Mammoth or magnetar Those oddities mean astronomers are not totally sure what it is, Stanek says.
"My analogy is that we have been studying elephants, and our project has found the biggest elephant ever," he says. "There's a chance it is not an elephant, but a mammoth, a relic from the earlier universe."
It might be a different exotic object called a magnetar, a special kind of neutron star with an intense magnetic field. But ASASSN-15lh is more powerful than magnetars can possibly become, so that seems unlikely, says Steve Rodney at the University of South Carolina.
It could also be the remains of a star being pulled apart by a supermassive black hole, or an ordinary supernova that is being magnified by a cosmic lens, an effect of gravity. But both of those theories are unlikely: the explosion lacks the hydrogen and helium that would be the hallmarks of a black hole's lunch, and the explosion's relatively close distance makes lensing implausible.
ASASSN-15lh has just moved behind the sun, but astronomers have been taking new data until this week with the space-based Swift Gamma Ray Burst Explorer. The team was awarded time on the Hubble Space Telescope and hope to use it in a couple months – after the object fades a little bit, so the telescope can see its host galaxy in better detail. The Hubble observations will give astronomers more insight into the strange object's origins. Stanek says he's eager to hear new theories about what it could be.
"When you see something which has never been seen before, you get excited," he says. "It doesn't happen that often."
Journal: Science, 10.1126/science.aac9613

Proračuni i simulacije kažu da negde daleko van Kujperovog pojasa mora da postoji planeta mase desetak puta veće od Zemlje.

http://www.sciencemag.org/news/2016/01/feature-astronomers-say-neptune-sized-planet-lurks-unseen-solar-system

Članak je dugačak pa ovde stavljam samo prvih par pasusa.

QuoteThe solar system appears to have a new ninth planet. Today, two scientists announced evidence that a body nearly the size of Neptune—but as yet unseen—orbits the sun every 15,000 years. During the solar system's infancy 4.5 billion years ago, they say, the giant planet was knocked out of the planet-forming region near the sun. Slowed down by gas, the planet settled into a distant elliptical orbit, where it still lurks today.

The claim is the strongest yet in the centuries-long search for a "Planet X" beyond Neptune. The quest has been plagued by far-fetched claims and even outright quackery. But the new evidence comes from a pair of respected planetary scientists, Konstantin Batygin and Mike Brown of the California Institute of Technology (Caltech) in Pasadena, who prepared for the inevitable skepticism with detailed analyses of the orbits of other distant objects and months of computer simulations. "If you say, 'We have evidence for Planet X,' almost any astronomer will say, 'This again? These guys are clearly crazy.' I would, too," Brown says. "Why is this different? This is different because this time we're right."

Outside scientists say their calculations stack up and express a mixture of caution and excitement about the result. "I could not imagine a bigger deal if—and of course that's a boldface 'if'—if it turns out to be right," says Gregory Laughlin, a planetary scientist at the University of California (UC), Santa Cruz. "What's thrilling about it is [the planet] is detectable."

Batygin and Brown inferred its presence from the peculiar clustering of six previously known objects that orbit beyond Neptune. They say there's only a 0.007% chance, or about one in 15,000, that the clustering could be a coincidence. Instead, they say, a planet with the mass of 10 Earths has shepherded the six objects into their strange elliptical orbits, tilted out of the plane of the solar system.

The orbit of the inferred planet is similarly tilted, as well as stretched to distances that will explode previous conceptions of the solar system. Its closest approach to the sun is seven times farther than Neptune, or 200 astronomical units (AUs). (An AU is the distance between Earth and the sun, about 150 million kilometers.) And Planet X could roam as far as 600 to 1200 AU, well beyond the Kuiper belt, the region of small icy worlds that begins at Neptune's edge about 30 AU.

If Planet X is out there, Brown and Batygin say, astronomers ought to find more objects in telltale orbits, shaped by the pull of the hidden giant. But Brown knows that no one will really believe in the discovery until Planet X itself appears within a telescope viewfinder. "Until there's a direct detection, it's a hypothesis—even a potentially very good hypothesis," he says. The team has time on the one large telescope in Hawaii that is suited for the search, and they hope other astronomers will join in the hunt.

Mene danas da ubiješ ne bih više znao da kažem koliko se "zvanično" računa da ima planeta u našem solarnom sistemu. 

Više mi vrediš živ, i zato da te informišem: bilo je devet, a (za) sada je osam.