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ми аз нямам какво повече да добавя
биолог съм, но се интересувам по малко и от нещата извън планетата ни
понеже ти ми отправи препоръка
и аз ще ти отправя една
има едно мн хубаво филмче (макар и малко старичко)
the expanding universe
4 серии, кратко и ясно
иначе напиши expanding universe в гуглето и виж първите няколко резултата
например това:
Before Hubble, astronomers could not decide if the universe was 10 billion or 20 billion years old," said team leader Wendy Freedman of the Observatories of the Carnegie Institution of Washington. "The size scale of the universe had a range so vast that it didn't allow astronomers to confront with any certainty many of the most basic questions about the origin and eventual fate of the cosmos. After all these years, we are finally entering an era of precision cosmology. Now we can more reliably address the broader picture of the universe's origin, evolution and destiny."
The team's precise measurements are the key to learning about the universe's rate of expansion, called Hubble's constant. Measuring Hubble's constant was one of the three major goals for NASA's Hubble Space Telescope when it was launched in 1990.
For the past 70 years astronomers have sought a precise measurement of Hubble's constant, , ever since astronomer Edwin Hubble realized that galaxies were rushing away from each other at a rate proportional to their distance, i.e. the farther away, the faster the recession.For many years, right up until the launch of the Hubble telescope -- the range of measured values for the expansion rate was from 50 to 100 kilometers per second per megaparsec (a megaparsec, or mpc, is 3.26 million light years).
The team measured the Hubble Constant to be 70 km/sec/mpc, with an uncertainty of 10 percent. This means that a galaxy appears to be moving 160,000 miles per hour faster for every 3.3 million light-years away from Earth.
The truth is out there, and we will find it," said Dr. Robert Kirshner of Harvard University. "We used to disagree by a factor of two; now we are just as passionate about ten percent. A factor of two is like being unsure if you have one foot or two. Ten percent is like arguing about one toe. It's a big step forward." Added Robert Kennicutt of the University of Arizona, a co-leader of the team: "Things are beginning to add up. The factor-of-two controversy is over."
The team used the Hubble telescope to observe 18 galaxies out to 65 million light-years. They discovered almost 800 Cepheid variable stars, a special class of pulsating star used for accurate distance measurement. Although Cepheids are rare, they provide a very reliable "standard candle" for estimating intergalactic distances. The team used the stars to calibrate many different methods for measuring distances.
"Our results are a legacy from the Hubble telescope that will be used in a variety of future research," said Jeremy Mould of the Australian National University, also a co-leader of the team. "It's exciting to see the different methods of measuring galaxy distances converge, calibrated by the Hubble Space Telescope."
Combining Hubble's constant measurement with estimates for the density of the universe, the team determined that the universe is approximately 12 billion years old -- similar to the oldest stars. This discovery clears up a nagging paradox that arose from previous age estimates. The researchers emphasize that the age estimate holds true if the universe is below the so-called 'critical density' where it is delicately balanced between expanding forever or collapsing. Alternatively, the universe is pervaded by a mysterious 'dark force' pushing the galaxies farther apart, in which case the Hubble measurements point to an even older universe.
The universe's age is calculated using the expansion rate from precise distance measurements, and the calculated age is refined based on whether the universe appears to be accelerating or decelerating, given the amount of matter observed in space. A rapid expansion rate indicates the universe did not require as much time to reach its present size, and so it is younger than if it were expanding more slowly.
The Hubble Space Telescope Key Project Team is an international group of 27 astronomers from 13 different U.S. and international institutions. The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc. for NASA, under contract with NASA's Goddard Space Flight Center, Greenbelt, MD.
за да ти спестя време наблегнах на нещо
просто ориентировъчно
но за това, един учен да позволи на въображението му да надгражда знанията му ..напълно те разбрах!
как си по новото време
Редактирано от Pisunqk на 12.03.07 17:13.
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Re: въпрос [re: Cтaниcлaв!]
