Astronomija i sve o Svemiru

[lawl_]

što je i nekako logično, jer gravitacija opada sa kvadratom rastojanja :)

[Loopy]

A ok, to vec ima smisla. Ali mislim da je zbunjujuce reci "trebao bi da ides brzinom od 500 km/s da bi izasao iz galaksije, ali ako racunas tu brzinu iz Zemljine orbite u relaciji sa Zemljom". Mislim kada bi neko dizajnirao raketu, on bi gledao koju brzinu mora da razvije na ivici galaksije da bi presao taj neki galakticki "zid", zar ne?

[Dule_smor]

pa da, ta brzina od 500km/s je sa polozaja suncevog sistema, blize centru galaksije je veca i obruto ofc:)

 

evo jedno zanimljivosti na koju slucajno naleteh, proton sa kinetickom energijom lopte za bejzbol koja se krece 100km/h:)

 

http://en.wikipedia.org/wiki/Oh-My-God_particle

[Rejz]

Evo primer, brzina od 525 km/s bi bila potrebna kada bi objekat hteo da napusti suncev sistem, a pocetna lokacija mu je u samoj blizini sunca. Sto je objekat dalji od sunca to je manja brzina potrebna da pobegne gravitacionom polju istog.

 

U stvari samo ponavljam ono sto je dule vec rekao. Poenta je da taj objekat mora prvobitno da razvije brzinu potrebnu da napusti galaksiju, a zatim sto se vise udaljava od centra gravitacije nase galaksije (Sagittarius A crna rupa) to je manja brzina potrebna. Ova brzina od 537 km/s se moze postici i slingshot efektom, tako je i Voyager iskoristio Saturnov slingshot efekat da dostigne dovoljnu brzinu za napustanje suncevog sistema.

Edit: Dok sam ja kucao ovaj post i afk-ovao, dule je dodatno napisao isto sto i ja i obrnuto :D

Edited September 24, 2013 by Rejz

[Astora]

Scott Kelly Becomes U.S. Astronaut to Spend the Most Time Living in Space

Just before the 15^th anniversary of continuous human presence on the International Space Station, U.S. astronaut and commander of the current Expedition 45 crew, Scott Kelly, is breaking spaceflight records. On Friday, Oct. 16, Kelly will begin his 383^rd day living in space, surpassing U.S. astronaut Mike Fincke’s record of 382 cumulative days.

Watch a YouTube video about Kelly and his year-long mission.

Breaking such a record for time in space is important because every additional day helps us better understand how long-duration spaceflight affects bodies and minds, which is critical to advancing NASA’s journey to Mars. Fifteen years of living and working off the Earth also is improving the quality of our lives here on Earth as scientists and engineers apply the knowledge gained from investigations aboard the unique microgravity laboratory.

Kelly will break another record Oct. 29 on his 216^th consecutive day in space, when he will surpass astronaut Michael Lopez-Alegria’s record for the single-longest spaceflight by an American. Lopez-Alegria spent 215 days in space as commander of the Expedition 14 crew in 2006.

Each additional day in orbit as part of the one-year mission along with cosmonaut Mikhail Kornienko, Kelly will continue to add to his record and to our understanding of the effects of long-duration spaceflight. The pair arrived at the space station in March and are participating in studies during their 342 days in space that provide new insights into how the human body adjusts to weightlessness, isolation, radiation and stress of long-duration spaceflight. Kelly’s twin brother, former astronaut Mark Kelly, will participate in parallel twin studies on Earth to help scientists compare the effects on the body and mind in space.

The investigations in progress on the space station will help scientists better understand how to protect astronauts as they travel into deep space and eventually on missions to the Red Planet. The strong U.S.-Russian collaboration during the one-year mission is an example of the global cooperation aboard the space station that is a blueprint for international partnerships to advance shared goals in space exploration. Strengthening international partnerships will be key in taking humans deeper into the solar system.

Kelly is scheduled to return to Earth on March 3, 2016, by which time he will have compiled 522 total days living in space during four missions.

Kelly is not the only human breaking records for time in space. Expedition 44 commander Gennady Padalka broke the 10-year-old record for the number of cumulative days in space June 28, as he reached 804 days in space. When he returned to Earth Sept. 11, Padalka had spent 879 days living and working in space.

Kelly, Padalka, and the more than 200 people who have visited the space station are contributing to the development of capabilities to enable a sustainable human presence in deep space.

 

[reki]

i dalje mi je smesan naziv topika

sve o svemiru :DD

[traktori]

Astoronomija

Sve o svemiru

[Dule_smor]

Padalka car, skoro 1000 dana u svemiru. Mator je već, al valjda će još jednom da ga pošalju da obori i taj rekord:)

[Astora]

Vidi ovu dvojcu, koje ste vi ženetine. Pa dajte koju reč podrške za čoveka sa fotke.

Ako se ne varam, vreme gore sporije teče?

[Dule_smor]

Jedino ako se krecu relativistickim brzinama bliskim brzinama svetlosti, ovim brzinama kojima se krece ISS mozda sporije max minut na godinu dana:)

[ZOOM_]

Ma da, sigurno je da tece i mora biti da je sporije, bar za duplo. Garant su izbacili  letnje i zimsko racunanje vremena, pa se toliko i ne primeti.

[Astora]

Jedino ako se krecu relativistickim brzinama bliskim brzinama svetlosti, ovim brzinama kojima se krece ISS mozda sporije max minut na godinu dana:)

Pitanje je, posle toliko dana provedenih gore, kako će njegov organizam reagovati kad se vrati na zemlju, pogotovo noge i kretanje? Znam da imaju sprave za vežbanje ali opet, gore je toliko dugo.

[Dandy]

Ako se ne varam, vreme gore sporije teče?

Zapravo bi trebalo da teče brže, pošto je u orbiti slabija gravitacija.

[Zwerko]

Will this European satellite confirm Einstein’s last unproven idea?

The Lisa Pathfinder will test equipment for an orbiting observatory that will peer into the universe’s darkest corners
 Lisa Pathfinder

It was perhaps the greatest scientific achievement of the 20th century. And next week space scientists will celebrate the 100th anniversary of the publication of Albert Einstein’s theory of general relativity in fitting style – by launching a probe to help demonstrate the accuracy of the theory’s last unproven prediction: the existence of gravitational waves.

At 4.15am on 2 December, the satellite, known as Lisa Pathfinder, is scheduled to be blasted into orbit from the European Space Agency’s centre in Kourou, French Guiana. It will carry equipment that will be tested as components for a future orbiting gravitational wave observatory.

“The theory of general relativity is the scientific equivalent of Michelangelo’s Sistine Chapel,” said Pedro Ferreira, professor of astrophysics at Oxford University. “Both are unique works of genius and each could only have been done by one individual. And it is quite stunning that the Lisa Pathfinder satellite – which is designed to help find gravitational waves whose existence is predicted by the theory – is going to be launched on the exact anniversary of the publication of Einstein’s work.”

Gravitational waves are thought to be hurled across space when stars start throwing their weight around, for example, when they collapse into black holes or when pairs of super-dense neutron stars start to spin closer and closer to each other. These processes put massive strains on the fabric of space-time, pushing and stretching it so that ripples of gravitational energy radiate across the universe. These are gravitational waves.

Observations by US astronomers Joseph Taylor and Russell Hulse in the 1980s provided key supporting evidence of their existence. The pair showed that a neutron star, now known as the Hulse-Taylor pulsar, was part of a binary system whose orbit was decaying at a rate consistent with it pumping out gravitational waves. This work won Hulse and Taylor the 1993 Nobel prize in physics. Since then, physicists have tried to spot gravitational waves directly, using ground-based devices with a common design: two long arms, set at right angles to each other, extending from a central point.

When a gravitational wave strikes, it should temporarily shrink one arm and slightly extend the other. That change can then be measured – albeit with considerable difficulty, because any change induced in an arm’s length by a gravitational wave will only be a few hundred billion-billionths of a metre.

So far, researchers have yet to detect such changes. Once they do, one of the final hurdles to a complete understanding of the makeup of our universe will have been achieved. However, they are now extending their efforts to space because, in orbit, it should be possible to fly detectors that are 5 million kilometres apart and which will be better able to spot the compressing and stretching of space-time.

“Over these huge distances, the effect of a gravitational wave is much greater and so it becomes much easier to detect one,” said Paul McNamara, the mission’s project scientist.

The Pathfinder probe will test equipment that will later be used to build a full-scale orbiting gravitational wave detector, a device that will be known as Lisa, the Laser Interferometer Space Antenna. However, astronomers will have to wait some time before it arrives because the European Space Agency does not plan to launch Lisa until 2034.

“It is a simply a matter of budgets. There are so many other great space projects competing for money,” said McNamara. “Nevertheless, a space-based gravitational wave observatory will revolutionise astronomy. We are not merely building a detector. We will have a machine that will use gravitational waves to study the universe.

“It will be an observatory and it will use a completely new medium to peer into the universe’s dark corners. Of course, a great many technological hurdles will have to be overcome. This is a very ambitious project. Nevertheless, we believe we can do it.”

At the heart of Lisa Pathfinder are two 2kg cubes of gold and platinum. These will be allowed to float free inside the craft, while being shielded from all forms of radiation and particle bombardment. The task of Lisa Pathfinder will then be to determine if it is possible to use lasers to measure deviations in their movements inside the craft with an accuracy of a trillionth of a metre. “We have worked very hard on this and we are sure that we can do it,” added McNamara.

“This is a great mission and the fact that it is going to be launched exactly 100 years after the publication about general relativity on 2 December, 1915, just makes the experience all the richer for us.”

THEORY THAT WAS YEARS IN THE MAKING
In his On the General Theory of Relativity, Albert Einstein took previous ideas about gravity – which had been seen as a force acting between objects – and replaced them with a description of it as being a geometric property of space and time.

Many predictions emanated from this idea: the existence of super-dense collapsed stars – now known as black holes – gravitational lensing, in which light from a distant source is distorted by a huge, intermediary object, gravitational waves and many others.

“All of these phenomena have now been observed – with one exception, and that is gravitational waves,” said Pedro Ferreira, whose book The Perfect Theory, published last year, outlined the struggles that Einstein endured in working out his theory.

“It was like a piece of art, the effort of one man, who struggled for seven years just to get things right,” said Ferreira. “He worked on his ideas and equations exhaustively and then presented his theory in a series of lectures in November 1915 culminating in a final presentation on the 24th. Then he published in an unbelievably short time on 2 December.”

At the time the publication of Einstein’s theory attracted little attention. Europe was then convulsed by war. However, the theory made global headlines shortly after the war, when the British astronomer Arthur Eddington studied star positions during a total solar eclipse and found their light was being bent by the Sun in a manner consistent with Einstein’s theory.

However, it took the development of radio astronomy to fully underline the importance of general relativity. “Astronomers began to detect ultra-energetic, incredibly dense objects that could only be understood in terms of their gravitational fields,” said Ferreira. “Gravity had to be really, really important, and the only theory that makes it possible for us to understand gravity is general relativity.”

 

 

 

 

http://www.theguardian.com/science/2015/nov/21/satellite-to-solve-einstein-last-theory?CMP=fb_gu

Vrh je zapravo sto ce taj satelit koji ce definitivno potvrditi teoriju biti lansiran otprilike 2034. godine jer nemaju para :(

Edited November 23, 2015 by Zwerko

[Dule_smor]

to je otprilike treci satelit koji se lansira da potvrdi teoriju relativnosti i kao uvek bude potvrdjena, ali sa nedovoljnom prezinoscu ili tako nesto lol...sve je laz, jel tako kori!

[BarcaS take 2]

Ako se ne varam, vreme gore sporije teče?

Zapravo bi trebalo da teče brže, pošto je u orbiti slabija gravitacija.

https://en.wikipedia.org/wiki/Twin_paradox

[Dule_smor]

da ne otvaram nov topik, prvo uspesno vertikalno spusanje neke rakete iz orbite na Zemlju

http://www.b92.net/zivot/vesti.php?yyyy=2015&mm=12&dd=22&nav_id=1077287

[fatboy]

DAT ELON MUSK.....

....lol a zipa Jeff bezosa, koji background troll  lal


 

 

Edited December 23, 2015 by nigger

[bolkonski]

Možda nije baš za ovde, ali je povezano.

Srce mi je zaigralo.

[Lucky]

ahahaha, al' se vrti k'o animacija :))

[brue]

 Laser Interferometer Gravitational-wave Observatory

 

N E W S   R E L E A S E
For Immediate Release
February 11, 2016

GRAVITATIONAL WAVES DETECTED 100 YEARS AFTER EINSTEIN’S PREDICTION

LIGO Opens New Window on the Universe with Observation of Gravitational Waves
from Colliding Black Holes

WASHINGTON, DC/Cascina, Italy

For the first time, scientists have observed ripples in the fabric of spacetime called gravitational waves, arriving at the earth from a cataclysmic event in the distant universe. This confirms a major prediction of Albert Einstein’s 1915 general theory of relativity and opens an unprecedented new window onto the cosmos.

http://www.ligo.org/news/detection-press-release.pdf

http://ligo.org/science/Publication-GW150914/index.php

 

 

 

[bolkonski]

Upravo se završio vebkast. Uzbudljivo!

[absolute]

Bole ovlazio :)

[reki]

sve o svemiru

 

still funny

[Dule_smor]

Kinezi privode kraju ovo cudo, 500m jebena antena (da, znam da je vest iz februara)

http://www.dailygalaxy.com/my_weblog/2016/02/china-on-schedule-with-worlds-largest-radio-telescope-to-search-for-extraterrestrial-life.html