Preciznost GPS sistema kao potvrda Ajnštajnovih predviđanja relativnosti vremena

[Милан Меденица :)]

него, шта ви мислите о кугелблицима?

[zejak]

Ne treba Vam GPS (Global Positioning System) i Galileo (Satellite Navigation) kao potvrda Ajnštajnove teorije. Potreban Vam je samo njegov dokaz iz 1915. godine koji se tiče sledećeg:

"Jos od davnina je bilo poznato svim astronomima da Merkurova putanja nije elipsa već rozeta. Ljudi su pokušavali da oblik ove Merkurove putanje dobiju neanalitičkim rešavanjima kroz Ojlerov numerički metod pri čemu su koristili Njutnovu teoriju gravitacije kao opis dodatnih perturbativnih gravitacionih sila ostalih planeta solarnog sistema na sistem dva tela Sunce-Merkur. Smatrali su da je Merkurova putanja posledica neuračunavanja uticaja ostalih planeta tj. da se tu radi o problemu koji se ne može izračunati analitički kao što je to slučaj sa npr. poznatim problemom tri tela. Ovaj numerički metod zasnovan na Njutnovoj teoriji nije dao traženi rezultat koji je prethodno uočen u astronomskim posmatranjima. Kako niko u to vreme nije bio kadar da misli o nekoj alternativnoj teoriji gravitacije tj. svi su se držali Njitnove teorije gravitacije kao oslonca, stoga je čak i bilo predloga da se traži hipotetička planeta nazvana Vulkan koja bi trebalo da se nalazi izmedju Sunca i Merkura kako bi tada putanja Merkura bila rozeta usled njenog gravitacionog učinka. Naravno, ova planeta nikada nije pronadjena, pa je ovaj problem i dalje ostao nerešen u okviru Njutnove teorije gravitacije kao sile čija je brzina prostiranja beskonačna. Ajnštajn je prvi dobio uočen oblik Merkurove putanje rešavajući analitički  problem dvojnog sistema Sunce-Merkur, ali koristeći svoju teoriju gravitacije zasnovanu na interpretaciji gravitacione interakcije kao polja metrike zakrivljenog prostor-vremena čija je fizički relevantna "Osobina" krivina takvog prostor-vremena. Kažem fizički relevantna u smislu da je nepromenljiva "Osobina" zakrivljenog prostor-vremena u odnosu na tzv. lokalnu simetriju prostor-vremenskog kontinuuma."

GPS (Global Positioning System) i Galileo (Satellite Navigation) su samo primene, a ne dokazi.

[dragisa]

jel moze neko da mi obasni zasto mi gps uvek daje vecu brzinu kojom putujem nego kazaljka na tabli? razlika je uvek konstantna 8 km/h a preciznost pozicije je skroz riltajm, npr kad skrecem on pokazuje da skrecem itd. e sad mozda ima veze sa mojom tablom koju sam vec menjao bas zbog zaglavljenog brzinomera, ali racunam da je sad dobra jer je stavljena ganc nova.

[cloudking]

dragisa be, pa nije ovo tehnicki forum facenew22222222

[Aquilius Cratus]

dragisa be, pa nije ovo tehnicki forum :P

Ima nas raznih. facenew22222222

[dragisa]

znam da nije tehnicki ali posto pricate o nekom kasnjenju reko da pitam da nije to uzrok? a vi oprostite meni na drskosti.

[sqny]

jel moze neko da mi obasni zasto mi gps uvek daje vecu brzinu kojom putujem nego kazaljka na tabli? razlika je uvek konstantna 8 km/h a preciznost pozicije je skroz riltajm, npr kad skrecem on pokazuje da skrecem itd. e sad mozda ima veze sa mojom tablom koju sam vec menjao bas zbog zaglavljenog brzinomera, ali racunam da je sad dobra jer je stavljena ganc nova.

GPS je u principu je jako precizan reda ms i iz toga moze pouzdano da odredi brzinu. Verovatno da ti je nekvalitetan prijemnik  facenew22222222

[dragisa]

nokia 5800 facenew22222222 jedino sto sam iskljucio podrsku lociranja preko mobilne mreze jer sam isao u inostranstvo, da nije to?

[cloudking]

Ja sam cuo da table generalno daju vecu brzinu nego GPS a da je GPS zapravo najtacniji. Razlog za to je, kako sam cuo, bezbednost...

ZAto mi je bio cudan tvoj slucaj gde je suprotno...

[dragisa]

o kreten, lose sam napisao u prvom postu.

to je i kod mene slucaj, GPS mi daje manju a tabla vecu brzinu za cca 8km/h. cak sam i ja pomislio da moze biti namerno tako kalibrisana bas zbog bezbednosti, ali reko da pitam.

a to za preciznos gps to i ja vidim po forumima da se svi kunu u njegovu preciznost ocitavanja brzine, pa mi je to jos vise ubacivalo rovca, ¨sta se desava?¨.

[cloudking]

Onda je ona bezbednosna varijanta jedino objasnjenje... Jednostavno autokompanije kalibrisu brzinomer da pokazuje vecu brzinu nego sto jeste tako da si u vecini slucajeva ispod kriticne brzine... ko bi ga znao...

[dragisa]

eto resenija!!!!

777bakisin

[Milan Nikolic]

4. МАЈ 2011.

NASA's Gravity Probe B Confirms Two Einstein Space-Time Theories

NASA's Gravity Probe B (GP-0102_laugh mission has confirmed two key predictions derived from Albert Einstein's general theory of relativity, which the spacecraft was designed to test.

The experiment, launched in 2004, used four ultra-precise gyroscopes to measure the hypothesized geodetic effect, the warping of space and time around a gravitational body, and frame-dragging, the amount a spinning object pulls space and time with it as it rotates.

GP-B determined both effects with unprecedented precision by pointing at a single star, IM Pegasi, while in a polar orbit around Earth. If gravity did not affect space and time, GP-B's gyroscopes would point in the same direction forever while in orbit. But in confirmation of Einstein's theories, the gyroscopes experienced measurable, minute changes in the direction of their spin, while Earth's gravity pulled at them.

The findings are online in the journal Physical Review Letters.

"Imagine the Earth as if it were immersed in honey. As the planet rotates, the honey around it would swirl, and it's the same with space and time," said Francis Everitt, GP-B principal investigator at Stanford University. "GP-B confirmed two of the most profound predictions of Einstein's universe, having far-reaching implications across astrophysics research. Likewise, the decades of technological innovation behind the mission will have a lasting legacy on Earth and in space."

GP-B is one of the longest running projects in NASA history, with agency involvement starting in the fall of 1963 with initial funding to develop a relativity gyroscope experiment. Subsequent decades of development led to groundbreaking technologies to control environmental disturbances on spacecraft, such as aerodynamic drag, magnetic fields and thermal variations. The mission's star tracker and gyroscopes were the most precise ever designed and produced.

GP-B completed its data collection operations and was decommissioned in December 2010.

"The mission results will have a long-term impact on the work of theoretical physicists," said Bill Danchi, senior astrophysicist and program scientist at NASA Headquarters in Washington. "Every future challenge to Einstein's theories of general relativity will have to seek more precise measurements than the remarkable work GP-B accomplished."

Innovations enabled by GP-B have been used in GPS technologies that allow airplanes to land unaided. Additional GP-B technologies were applied to NASA's Cosmic Background Explorer mission, which accurately determined the universe's background radiation. That measurement is the underpinning of the big-bang theory, and led to the Nobel Prize for NASA physicist John Mather.

The drag-free satellite concept pioneered by GP-B made a number of Earth-observing satellites possible, including NASA's Gravity Recovery and Climate Experiment and the European Space Agency's Gravity field and steady-state Ocean Circulation Explorer. These satellites provide the most precise measurements of the shape of the Earth, critical for precise navigation on land and sea, and understanding the relationship between ocean circulation and climate patterns.

GP-B also advanced the frontiers of knowledge and provided a practical training ground for 100 doctoral students and 15 master's degree candidates at universities across the United States. More than 350 undergraduates and more than four dozen high school students also worked on the project with leading scientists and aerospace engineers from industry and government. One undergraduate student who worked on GP-B became the first female astronaut in space, Sally Ride. Another was Eric Cornell who won the Nobel Prize in Physics in 2001.

"GP-B adds to the knowledge base on relativity in important ways and its positive impact will be felt in the careers of students whose educations were enriched by the project," said Ed Weiler, associate administrator for the Science Mission Directorate at NASA Headquarters.

NASA's Marshall Space Flight Center in Huntsville, Ala., managed the Gravity Probe-B program for the agency. Stanford University, NASA's prime contractor for the mission, conceived the experiment and was responsible for the design and integration of the science instrument, mission operations and data analysis. Lockheed Martin Corp. of Huntsville designed, integrated and tested the space vehicle and some of its major payload components.

For more information about Gravity Probe B, visit:

http://www.nasa.gov/mission_pages/gpb/

and

http://einstein.stanford.edu/

Trent J. Perrotto, 202-358-0321

Headquarters, Washington

[email protected]

[Crveni Baron]

апсолут праве линије не постоји у природи, чак ни у свемиру.

A kako onda sa aksiomom o paralelama?

[Grizzly Adams]

апсолут праве линије не постоји у природи, чак ни у свемиру.

A kako onda sa aksiomom o paralelama?

То је занимљива прича.