Forum Klix.ba

MyTao wrote:

Arminovski wrote:

sinuhe wrote:Neki dan čitam o gravitacijskim valovima i piše da trajanje signala određuje masu crnih rupa.
E sad da li je trajanje signala povezano prosto sa energijom i da su samo iz toga zaključili masu?

Uf, kopas tamo gdje niko nije bio vec 15-tak godina...

Trebalo bi biti. Neka me ispravi neko ako neko zna bolje. Gravitacijski valovi sto ih mi detektujemo su od spajanja jako masivnih objekata. Crne rupe imaju samo masu, radius i rotaciju - znaci onda i momentum i energiju. Trebalo bi biti tako da razlicite mase daju razlicita vremena za vrijeme spajanja sto bi se prevelo u frekvenciju valova i vrijeme a onda i intenzitet (amplitudu). Separacija (udaljenost izmedju ta dva objekta) bi trebala isto da ima ulogu u frekvenciji i intenzitetu.

Vjerovatno da se pomocu gravitacijski valova moze odrediti kolika je crna rupa, ali u te valove je ukljuceno toliko drugih faktora da to i nije bas pouzdano mjerenje.

Crne rupe se mjere tako sto se mjere zvijezde, planete itd koje su u njenoj orbiti. Evo odlican link koji to objasnjava http://hubblesite.org/explore_astronomy ... 3_q14.html

Arminovski wrote:
Pozz

Ali u ovom kontekstu se ne zna gdje su ti objekti pa bi se masa odredjivala jedino preko oscilacija koje detektuje LIGO. Sto ne bi bilo pouzdano? LIGO kompenzira ove zemaljske vibracije pri proracunu. Vjerujem da su simulirali nama poznate scenarije kolizije dva objekta tako da mogu prepoznati relativno brzo o kakvim objektima bi se trebalo raditi. O kojim drugim faktorima govoris?

MyTao wrote:

Arminovski wrote:
Pozz

Ali u ovom kontekstu se ne zna gdje su ti objekti pa bi se masa odredjivala jedino preko oscilacija koje detektuje LIGO. Sto ne bi bilo pouzdano? LIGO kompenzira ove zemaljske vibracije pri proracunu. Vjerujem da su simulirali nama poznate scenarije kolizije dva objekta tako da mogu prepoznati relativno brzo o kakvim objektima bi se trebalo raditi. O kojim drugim faktorima govoris?

Ne znam, zar na gravitacijske talase ne utice sve sto se nadje od crne rupe pa do zemlje recimo... sve sto ima masu ce na neki nacin uticati na te talase tako da bi bilo jako tesko izracunati masu crne rupe na taj nacin. To mi je kao da u bazenu koji je pun ljudi pokusavamo izracunati masu osobe na drugom kraju po valovima koji dolaze do nas

Mozda se varam... zanimljiva tema svakako...

This was the genius of the fake signal injection: Whatever the prior belief of an individual scientist might be, it gave him or her reason to doubt it. A scientist who believed that the current generation of instruments was simply not up to the task would have to allow for the possibility that it was. A scientist tempted to elevate a signal because of the benefits of a real detection would have to temper his or her enthusiasm to avoid making a false claim. The fake injection bugaboo forced us to keep an open mind, apply skepticism and reason, and examine the evidence at face value.
It’s hard to appreciate how important this is. Some gravitational wave experiments had suffered in the past from overstated claims, and the LIGO/Virgo collaboration had grown in size to the point that a consensus over standards was hard to achieve. It was not clear before 2011 that any level of evidence would be sufficient.

Now—finally—a fake signal had made us feel prepared for real success.

From 2010 to 2015, the Initial LIGO detectors at both the LIGO Hanford Observatory and the LIGO Livingston Observatory had been dismantled, and the Advanced LIGO detectors were built and installed in their place. These new detectors included a range of upgrades, all intended to improve the sensitivity of the instruments and make detections more likely. The improvements included larger mirrors, more powerful lasers, and active feedback loops for better seismic isolation. Instead of suspending the test masses by wires, they were now hung on thin strands of glass resistant to thermal vibrations. The improvements were designed to increase the reach of LIGO by 10 times, and so increase a thousand-fold the volume of space that could be searched for rare events.

Good thing. In the early morning of Sept. 14, 2015, our detectors and associated search pipeline software identified an event consistent with a binary black hole merger some 1.3 billion light-years away. It was loud, and clearly inconsistent with detector or terrestrial noise, with a confidence of better than 99.9999 percent. Wow ... so soon after turn-on, and so loud; could nature really have been so kind? We named it GW150914.

But—could it be a blind injection, even though there were not supposed to be any? Within a few hours, many of us (including Alan) were on a telecon to discuss it. Mike Landry, one of the members of the 2010 “blind injection team,” was present, and said that there was no blind injection team convened for the engineering run, and that this wasn’t a blind injection. Had the discovery come a few days later, during our observing run, the blind injection team might have been active, and he might have been sworn to secrecy. But at this time, blind injections were simply not an option. Still, we doubted him. We asked to look at the secret blind injection data channel. The response: “Go right ahead.”

We looked and found nothing. The physicist in charge of hardware injections, Jeff Kissel, wrote so in our electronic logbook: “There were NO Transient Injections during G184098 Candidate Event.” It was his shortest e-log entry ever. Later, it won the award for best e-log entry of the year.

Connaisseur Karlin wrote:tokom predveceri



tokom noci , tj. u super-fazi



(fotke su moje) SuperMjesec

Arminovski wrote:
Super fotke!

Connaisseur Karlin wrote:tokom predveceri



tokom noci , tj. u super-fazi



(fotke su moje) SuperMjesec

TouringBiker wrote:

Connaisseur Karlin wrote:tokom predveceri



tokom noci , tj. u super-fazi



(fotke su moje) SuperMjesec

Čime je ovo snimano, ako mogu pitati? Koji objektiv, ili je teleskop s nastavkom za priključenje aparata na okular? Koje podešavanje osjetljivosti (ASA), koliko duga ekspozicija? Jeli potrebno pokretati aparat na stativu da se korigira kretanje mjeseca?

Uvijek sam volio eksperimentisati s noćnom fotografijom, ali nisam probao s mjesecom.

Connaisseur Karlin wrote:

TouringBiker wrote:
Čime je ovo snimano, ako mogu pitati? Koji objektiv, ili je teleskop s nastavkom za priključenje aparata na okular? Koje podešavanje osjetljivosti (ASA), koliko duga ekspozicija? Jeli potrebno pokretati aparat na stativu da se korigira kretanje mjeseca?

Uvijek sam volio eksperimentisati s noćnom fotografijom, ali nisam probao s mjesecom.

Canon Power Shot sx230 HS zomm je 14x ,prije 3 ili 4 godine,a pokusaj kupiti isit model,ali nova verzija ; fotkala sam sa svog balkona Svi vole moje fotke sa doticne kamere

evo ti primjri dvije fotke iz dva muzeja

TouringBiker wrote:

Connaisseur Karlin wrote:
Canon Power Shot sx230 HS zomm je 14x ,prije 3 ili 4 godine,a pokusaj kupiti isit model,ali nova verzija ; fotkala sam sa svog balkona Svi vole moje fotke sa doticne kamere

evo ti primjri dvije fotke iz dva muzeja

Hvala, ma imam ja DSLR Canona 500D i odvojeni objektiv Tamron 18-200mm, mislio sam da je neka jača kamera, ne compact. Super su ti slike. Koji je ovo muzej sa DC-3 avionom?

Connaisseur Karlin wrote:

TouringBiker wrote:Hvala, ma imam ja DSLR Canona 500D i odvojeni objektiv Tamron 18-200mm, mislio sam da je neka jača kamera, ne compact. Super su ti slike. Koji je ovo muzej sa DC-3 avionom?

Hanry Ford Detroit Hvala odlican je model,takodje rplaniram kupiti novu verziju i naravno,teleskop

TouringBiker wrote: OK i kontao sam da je Amerika, jer muzeje avijacije po Europi otprilike znam, i šta ima u kojemu.

Objektiv tvog aparata u stvari ima veći raspon nego moj objektiv, jer kod tebe odgovara 28-400mm kod starih aparata sa filmom ("Leica" format), a moj 28-300 - tako da ja na najjačem tele-položaju ne mogu približiti toliko; morao bih nabaviti 18-270 za DSLR umjesto 18-200. Druga je priča što su ovi objektivi za DSLR optički kvalitetniji, imaju veću prednju leću, više elemenata itd.

Uz teleskop ćeš morati uzeti i adapter da ga možeš nakačiti na DSLR aparat...

https://www.amazon.com/Deluxe-Telescope ... B0053ZJW5G

http://www.celestron.com/browse-shop/as ... eos-camera

https://www.amazon.com/Telescope-Camera ... B002F8Q2ZC

Tu je još najjeftinija varjanta upecati neki od adaptera za stare Praktica SLR fotoaparate sa filmom (od njih se isto mogu naći jeftini produžni prstenovi, mijeh i mikroskop-adapter, to sam sve nekad imao), a onda kupiti adapter za Praktica M42 navoj na onaj tip bajonet priključka koji ima aparat koji uzmeš - ovisno jeli Canon, Nikon, Pentax, Olympus...

http://www.ebay.com/itm/T2-T-Telescope- ... 0800666158

https://www.amazon.co.uk/pentax-Zeiss-P ... B001CX1HZ6

S tim adapterom ti se otvori pristup ka veoma širokoj paleti opreme sa M42 priključkom...

TouringBiker wrote:
Čime je ovo snimano, ako mogu pitati? Koji objektiv, ili je teleskop s nastavkom za priključenje aparata na okular? Koje podešavanje osjetljivosti (ASA), koliko duga ekspozicija? Jeli potrebno pokretati aparat na stativu da se korigira kretanje mjeseca?

Uvijek sam volio eksperimentisati s noćnom fotografijom, ali nisam probao s mjesecom.

SmokingMan wrote:Oh,večeras se očekuje vrhunac meteorske kiše Geminidi,nadam se da će vrijeme ići na ruku nama posmatračima.

Connaisseur Karlin wrote:

SmokingMan wrote:Oh,večeras se očekuje vrhunac meteorske kiše Geminidi,nadam se da će vrijeme ići na ruku nama posmatračima.

cekam vase fotke

SmokingMan wrote:

Connaisseur Karlin wrote:

SmokingMan wrote:Oh,večeras se očekuje vrhunac meteorske kiše Geminidi,nadam se da će vrijeme ići na ruku nama posmatračima.

cekam vase fotke

Na žaslot nemam DLSR kameru (možda i bude na proljeće),ja bih se prije oslonio na neke druge sa ovoga foruma,prije svega mislim na Arminovskog.

Connaisseur Karlin wrote:

SmokingMan wrote:
Na žaslot nemam DLSR kameru (možda i bude na proljeće),ja bih se prije oslonio na neke druge sa ovoga foruma,prije svega mislim na Arminovskog.

hvala cekamo Arminovskog

Arminovski wrote:

Connaisseur Karlin wrote:

SmokingMan wrote:
Na žaslot nemam DLSR kameru (možda i bude na proljeće),ja bih se prije oslonio na neke druge sa ovoga foruma,prije svega mislim na Arminovskog.

hvala cekamo Arminovskog

Ha?? Ja se ne bavim fotografijom.

Sentinel wrote:Šta mislite o ovoj hipotezi između stećaka i supernove?

https://alancatovic.wordpress.com/2016/ ... -zvijezda/

The Not-So-Fine Tuning of the Universe
There’s more than one way to build a universe suitable for life.

BY FRED ADAMS
ILLUSTRATIONS BY JACKIE FERRENTINO
JANUARY 19, 2017

In short, the parameters of our universe could have varied by large factors and still allowed for working stars and potentially habitable planets. The force of gravity could have been 1,000 times stronger or 1 billion times weaker, and stars would still function as long-lived nuclear burning engines. The electromagnetic force could have been stronger or weaker by factors of 100. Nuclear reaction rates could have varied over many orders of magnitude. Alternative stellar physics could have produced the heavy elements that make up the basic raw material for planets and people. Clearly, the parameters that determine stellar structure and evolution are not overly fine-tuned.

Given that our universe does not seem to be particularly fine-tuned, can we still say that our universe is the best one for life to develop? Our current understanding suggests that the answer is no. One can readily envision a universe that is friendlier to life and perhaps more logical. A universe with stronger initial density fluctuations would make denser galaxies, which could support more habitable planets than our own. A universe with stable beryllium would have straightforward channels available for carbon production and would not need the complication of the triple-alpha process. Although these issues are still being explored, we can already say that universes have many pathways for the development of complexity and biology, and some could be even more favorable for life than our own. In light of these generalizations, astrophysicists need to reexamine the possible implications of the multiverse, including the degree of fine-tuning in our universe.

http://nautil.us/issue/44/luck/the-not_ ... e-universe

The universe would have been habitable even if the forces of electromagnetism and gravity had been stronger or weaker.