R
RAYTHEON23
Гостин
NE sum procital vo nitu edna recenica za fenomenov vo knigit koi gi citav astronomski??
habl imal sreka a i nie sreken sum sto go gledam ovoj nastan_FOTKAVA MNOGU E ZAKON
sreken sum za fotkata
))))))))):pos2::pos2::pos2::pos2::pos2::pos2::pos2::pos2:
habl imal sreka a i nie sreken sum sto go gledam ovoj nastan_FOTKAVA MNOGU E ZAKON
sreken sum za fotkata
))))))))):pos2::pos2::pos2::pos2::pos2::pos2::pos2::pos2:
Annabel
Неутрална*
- Член од
- 18 декември 2008
- Мислења
- 1.298
- Поени од реакции
- 183
Неколку среќни луѓе во Индискиот Океан ќе бидат почастени со редок настан во понеделник кога ануларната соларна еклипса ќе го претвори Сонцето во темен диск со светлечки прстен оформен околу него.
Во соларните еклипси Месечината се движи помеѓу Сонцето и Земјата фрлајќи сенка на површината од Сонцето.
За разлика од тоталната еклипса каде што се фрла потполна сенка на Сонцето,кај ануларната еклипса се покрива мал одреден дел.
Разликата е во тоа што оние кои ќе бидат директно изложени и на вистинската локација ќе видат дека Месечината всушност го покрива цело Сонце за разлика од другите на кои што ќе им изгледа како мал дел да се има откинато од Сонцето.
Според ветеран од НАСА Фред Еспенак еклипсата ќе се движи од запад кон исток.
F
FallenHypaspist
Гостин
Како и да го гледаш закон е .
Него мене лично повеќе ме интересира да ли постоел живот на Марс.
На површината на Марс се откриени неколку пирамиди кои веројатно во блиска иднина ќе бидат истражувани.До пред некое време се мислеше дека биле игра на ветерот но со по долгите истражувања и снимања се зголеми шансата дека не се всушност никаква заебанција....
Ова ми е некако моментално најпривлечна ствар во астронимијата,археологијата,историјата,а ќе видиме можеби и во биологијата...Ќе видиме дали и како ќе се расчистат митолошките приказни околу 12-те планети (9 + Нибиру,Едната не знам како се викаше но митологијата ни кажува дека била лоцирана помеѓу Марс и Јупитери и била разнесена во атомска експлозија така да сега е појас од астероиди.Другата планета не ја знам
) и мистеријата за животот на Марс и Венера....
Black Night
Galvanize
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- 25 септември 2008
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Лудница е сликата на Hubble. Како стварно да не гледа некој. Ме плаши дури.
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- 21 октомври 2008
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tie mi se drugarcinja mikrobite na mars zaedno ednas javavme divi konji vo america
ne se losi ne se ni zeleni tie se bas onaka kool mikrobi sakaat sexs ama so pogled cudno mi bese toa kaj niv
ne se losi ne se ni zeleni tie se bas onaka kool mikrobi sakaat sexs ama so pogled cudno mi bese toa kaj niv
С
Спенсер
Гостин
некој да има некој текст за затемнување на сонцето???шо-како,зашто се дешава тоа??
Apokalipto
Tredici
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- 4 март 2007
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- 15.576
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Black Night
Galvanize
- Член од
- 25 септември 2008
- Мислења
- 327
- Поени од реакции
- 20
Една од поинтересните работи која не очекува оваа година е лансирањето на вселенското летало Kepler. Ова летало вредно 500 мил. долари на НАСА ке има мисија да зема податоци и слики од ѕвезди и планети во нашата галаксија за кои научниците сметаат дека е можно да има жив свет.
До сега научниците имаат детектирано 322 планети кои кружат околу други ѕвезди но повеќето од нив се гас џинови. За прв пат во историјата ова летало ке може да детектира и помали планети со слична димензија на нашата земја, за кои сметаат дека можеби се населени од жив свет. Ова летало ке користи моќен фотометар кој ке регистрира 100 000 ѕвезди и планети кои се наоѓаат пред нив. Секое најмало прекршување на светлината од планета ке биде регистрирано и ке може да се одреди големината на планетата со огромна прецизност.
Launch date/time: 2009 March 5 at 10:48 pm EST
До сега научниците имаат детектирано 322 планети кои кружат околу други ѕвезди но повеќето од нив се гас џинови. За прв пат во историјата ова летало ке може да детектира и помали планети со слична димензија на нашата земја, за кои сметаат дека можеби се населени од жив свет. Ова летало ке користи моќен фотометар кој ке регистрира 100 000 ѕвезди и планети кои се наоѓаат пред нив. Секое најмало прекршување на светлината од планета ке биде регистрирано и ке може да се одреди големината на планетата со огромна прецизност.
Launch date/time: 2009 March 5 at 10:48 pm EST
R
RAYTHEON23
Гостин
Soyuz Rocket Fills Breach Left by Loss Of Shuttle(po katastrofat vo kolumbija satlot-vokoj zagina i prviot evrein-ilan ramon koj go unisti ira;kiot reaktor vo bagdad)
By MICHAEL WINES
Published: Sunday, April 27, 2003
Filling in for NASA's grounded space shuttle, a Russian Soyuz rocket roared off a Kazakhstan launching pad into orbit today carrying a Russian and an American on a crucial mission to sustain the International Space Station.
The two crewmen, Yuri I. Malenchenko and Edward T. Lu, will replace a crew of two Americans and one Russian who were forced to extend their time in space after the Columbia disaster left NASA's shuttle fleet unable to send replacements.
A successful launching today was seen as absolutely vital to the space station's future, because the Russian space program provides the only means of sending humans into orbit until the American shuttles are certified to fly again and flights resume, perhaps early next year.
''The station can't work without the crew,'' Mikhail L. Pronin, the chief engineer at the Russian Space Agency's ground control center here, said in an interview. ''And without the crew, there is no program.''
Mr. Malenchenko, the 41-year-old flight commander, and Mr. Lu, 39, are flying a mission significantly altered by the Columbia disaster. Their main task will be to keep the space station up and running until another crew arrives in October, most likely on another Soyuz rocket.
They also will supervise experiments, including one monitoring the growth of crystals in weightless conditions and a second exploring the loss of bone density that plagues humans in weightless conditions.
A number of planned experiments were shelved because the Columbia disaster led the two space agencies to reduce the crew for today's launching from three to two, and to fill the extra space with food and other supplies for the station.
NASA's space shuttles, with a 25-ton payload, normally keep the space station fully supplied. Today's Soyuz launching carried only 2.5 tons of supplies in addition to the crew, and pilotless Russian Progress space freighters also can carry only 2.5 tons of cargo.
Russia has said it can launch as many as five missions this year, two of them manned, butmuch of the equipment for those missions remains on productions lines now.
Mr. Lu said he planned to pin a badge to his space suit to honor the crew of the Columbia.
''One of the things that we have been talking about, thinking about before the flight, is that they never really completed their mission,'' Mr. Lu said. ''We are doing what I think they would have wanted and what their families wished them to do -- to continue the process of flying into space.''
Investigators suspect that a piece of insulating foam that broke off the shuttle's external fuel tank and struck the left wing seconds after liftoff created a breach that later allowed hot gases to destroy part of the shuttle's superstructure.
The mission is unusual in that the crewmen leaving the station -- the Americans, Capt. Kenneth D. Bowersox of the Navy and Donald R. Pettit, and the Russian flight engineer Nikolai M. Budarin -- are to return to earth in a Soyuz capsule, landing on May 4 in Kazakhstan not far from the site of today's launching.
Space station crews normally return to earth in shuttles, and the Soyuz capsules, which are regularly docked to the station, are reserved for use in case of emergencies.
Mr. Pronin, the chief engineer at the Russian Space Agency's mission control center, said that the three-man crew now at the station was still receiving extra training in space to prepare for a return in the Soyuz capsule.
Mr. Lu and Mr. Malenchenko, one of Russia's most experienced astronauts, were initially trained to navigate the NASA shuttle to dock with the space station but received new instructions after the Columbia disaster in linking the Soyuz capsule to the station.
eve termini upotrebuvani vo astronomija:
Binary star
A binary star is a double star system having orbital revolution components that cause the twin stars (so called because they usually form from the same interstellar cloud) to orbit each other around a shared center of mass due to the 'mutual gravity' of the binary system.
Aphelion & Perihelion
Aphelion / Perihelion is an object's orbital point (in distance and time) around a star where the object's distance (on its elliptical orbit) from its parent star is farthest / closest. The terms apogee & perigee are used instead when referring to objects orbiting the Earth apoapsis & periapsis refers to orbits around all other bodies.
Astronomical Unit
This is slightly less than the mean distance from the Earth to the Sun, approx. 149,597,870.691km or about 93 million miles. The semi-major axis between the Earth and Sun is greater than one AU because one astronomical unit is the measure of an unperturbed circular orbit. If you were travelling at 160 kilometres/hour speed it would take at least a century to cover a distance of one AU.
Opposition
A planet further out from the Sun than Earth is in opposition at 180 degrees from the Sun, directly on the opposite side of the Earth. A planet in opposition is at its closest to, and at its best visibility from, Earth.
Precession
Precession is a circular motion about a body's axis of rotation. Like a giant the giroscope Earth has an axis that passes through its poles, precessing once every 27,700 years. This slow yet uniform rotation about the Earth's axis constantly changes coordinates on sky maps. The rotational axis never points in the same direction due to lunisolar and planetary precessions, causing the celestial equinoxes to drift westward.
Wane & Wax
A waning moon refers to the time between the full and new phases; a waxing moon refers to an increase in the illuminated lunar surface area.
Division of the Sky into Constellations
The sky (including both the northern and southern hemisphere) is divided into 88 constellations. A constellation is a grouping of stars usually resembling a mythical figure from Greek or Arabic folklore. Many constellations are easily recognisable in the sky e.g. the Big Dipper (also known as the Plough). These constellations act as guideposts to the heavens enabling astronomers, professional and amateur alike, to find their way around the night sky. So the constellations serve a practical function, rather than just being superficial patterns.
Every region of the sky is designated to a particular constellation, this facilitates the current, though rather old and peculiar, method of naming stars. In astronomy the stars are named according to their brightness (magnitude) and assigned Greek letters. For instance, the brightest star in theconstelatiomof sygnumis given the name Alpha Cygni, the second brightest Beta Cygni and so on, until one runs out of Greek letters that is, then its on to roman numerals.
Many of the stars also have common names as well e.g. Alpha Cygni is better known as Deneb. A few of the more famous constellations are: uursa major Orion - the Hunter, cassiopeahttp://www.astronomytoday.com/astronomy/cassiopeia.html, and the Southern Cross.
Celestial co-ordinate system
From the Earth, the constellations seem to be struck on the inside of a hollow sphere known as the celestial sphere. This sphere appears to rotate around the Earth in an east-west direction every 24 hours. A grid of lines known as right ascension and declination help astronomers locate stars on the celestial sphere, and star maps are a projection of the imaginary sphere onto a flat surface.
Right Ascension (R.A.)
R.A. is one of the co-ordinates used to locate positions on the celestial sphere. Lines run from the North to the South celestial pole and are similar to the Earth's lines of longitude, except that they are measured in units of time.
Declination (DEC.)
DEC. is one of the co-ordinates used to locate positions on the celestial sphere and it is measured in degrees. Lines run from East to West and are linked to the Earth's lines of latitude: stars of 0° Dec., for example, lie in the same plane as the Earth's equator.
Apparent Magnitude
This is a measure of apparent brightness, which is the visible-light brightness of a celestial object observed from Earth, depending on both the distance of the object and its actual or true brightness.
Absolute Magnitude
is the magnitude (visible-light brightness) that a celestial object would have if it were observed at a standard distance of 32.6 light years (10 parsecs). Absolute magnitude differs from apparent magnitude, which is a measure of how bright an object looks to an observer on the Earth.
Astronomers here on Earth use apparent magnitude. The brighter a star is the lower its magnitude, i.e. a star with a magnitude of 1.2 is brighter than one with mag. 3.0, and a star mag. -0.7 is brighter than one of mag. -0.1. During the 18th century the ratio between magnitudes was fixed at 2.5 (2.5118865 to be exact). This means that a star of a given magnitude is 2.5 times brighter than a star one magnitude dimmer.
i za asteroidi:
By MICHAEL WINES
Published: Sunday, April 27, 2003
Filling in for NASA's grounded space shuttle, a Russian Soyuz rocket roared off a Kazakhstan launching pad into orbit today carrying a Russian and an American on a crucial mission to sustain the International Space Station.
The two crewmen, Yuri I. Malenchenko and Edward T. Lu, will replace a crew of two Americans and one Russian who were forced to extend their time in space after the Columbia disaster left NASA's shuttle fleet unable to send replacements.
A successful launching today was seen as absolutely vital to the space station's future, because the Russian space program provides the only means of sending humans into orbit until the American shuttles are certified to fly again and flights resume, perhaps early next year.
''The station can't work without the crew,'' Mikhail L. Pronin, the chief engineer at the Russian Space Agency's ground control center here, said in an interview. ''And without the crew, there is no program.''
Mr. Malenchenko, the 41-year-old flight commander, and Mr. Lu, 39, are flying a mission significantly altered by the Columbia disaster. Their main task will be to keep the space station up and running until another crew arrives in October, most likely on another Soyuz rocket.
They also will supervise experiments, including one monitoring the growth of crystals in weightless conditions and a second exploring the loss of bone density that plagues humans in weightless conditions.
A number of planned experiments were shelved because the Columbia disaster led the two space agencies to reduce the crew for today's launching from three to two, and to fill the extra space with food and other supplies for the station.
NASA's space shuttles, with a 25-ton payload, normally keep the space station fully supplied. Today's Soyuz launching carried only 2.5 tons of supplies in addition to the crew, and pilotless Russian Progress space freighters also can carry only 2.5 tons of cargo.
Russia has said it can launch as many as five missions this year, two of them manned, butmuch of the equipment for those missions remains on productions lines now.
Mr. Lu said he planned to pin a badge to his space suit to honor the crew of the Columbia.
''One of the things that we have been talking about, thinking about before the flight, is that they never really completed their mission,'' Mr. Lu said. ''We are doing what I think they would have wanted and what their families wished them to do -- to continue the process of flying into space.''
Investigators suspect that a piece of insulating foam that broke off the shuttle's external fuel tank and struck the left wing seconds after liftoff created a breach that later allowed hot gases to destroy part of the shuttle's superstructure.
The mission is unusual in that the crewmen leaving the station -- the Americans, Capt. Kenneth D. Bowersox of the Navy and Donald R. Pettit, and the Russian flight engineer Nikolai M. Budarin -- are to return to earth in a Soyuz capsule, landing on May 4 in Kazakhstan not far from the site of today's launching.
Space station crews normally return to earth in shuttles, and the Soyuz capsules, which are regularly docked to the station, are reserved for use in case of emergencies.
Mr. Pronin, the chief engineer at the Russian Space Agency's mission control center, said that the three-man crew now at the station was still receiving extra training in space to prepare for a return in the Soyuz capsule.
Mr. Lu and Mr. Malenchenko, one of Russia's most experienced astronauts, were initially trained to navigate the NASA shuttle to dock with the space station but received new instructions after the Columbia disaster in linking the Soyuz capsule to the station.
eve termini upotrebuvani vo astronomija:
Binary star
A binary star is a double star system having orbital revolution components that cause the twin stars (so called because they usually form from the same interstellar cloud) to orbit each other around a shared center of mass due to the 'mutual gravity' of the binary system.
Aphelion & Perihelion
Aphelion / Perihelion is an object's orbital point (in distance and time) around a star where the object's distance (on its elliptical orbit) from its parent star is farthest / closest. The terms apogee & perigee are used instead when referring to objects orbiting the Earth apoapsis & periapsis refers to orbits around all other bodies.
Astronomical Unit
This is slightly less than the mean distance from the Earth to the Sun, approx. 149,597,870.691km or about 93 million miles. The semi-major axis between the Earth and Sun is greater than one AU because one astronomical unit is the measure of an unperturbed circular orbit. If you were travelling at 160 kilometres/hour speed it would take at least a century to cover a distance of one AU.
Opposition
A planet further out from the Sun than Earth is in opposition at 180 degrees from the Sun, directly on the opposite side of the Earth. A planet in opposition is at its closest to, and at its best visibility from, Earth.
Precession
Precession is a circular motion about a body's axis of rotation. Like a giant the giroscope Earth has an axis that passes through its poles, precessing once every 27,700 years. This slow yet uniform rotation about the Earth's axis constantly changes coordinates on sky maps. The rotational axis never points in the same direction due to lunisolar and planetary precessions, causing the celestial equinoxes to drift westward.
Wane & Wax
A waning moon refers to the time between the full and new phases; a waxing moon refers to an increase in the illuminated lunar surface area.
Division of the Sky into Constellations
The sky (including both the northern and southern hemisphere) is divided into 88 constellations. A constellation is a grouping of stars usually resembling a mythical figure from Greek or Arabic folklore. Many constellations are easily recognisable in the sky e.g. the Big Dipper (also known as the Plough). These constellations act as guideposts to the heavens enabling astronomers, professional and amateur alike, to find their way around the night sky. So the constellations serve a practical function, rather than just being superficial patterns.
Every region of the sky is designated to a particular constellation, this facilitates the current, though rather old and peculiar, method of naming stars. In astronomy the stars are named according to their brightness (magnitude) and assigned Greek letters. For instance, the brightest star in theconstelatiomof sygnumis given the name Alpha Cygni, the second brightest Beta Cygni and so on, until one runs out of Greek letters that is, then its on to roman numerals.
Many of the stars also have common names as well e.g. Alpha Cygni is better known as Deneb. A few of the more famous constellations are: uursa major Orion - the Hunter, cassiopeahttp://www.astronomytoday.com/astronomy/cassiopeia.html, and the Southern Cross.
Celestial co-ordinate system
From the Earth, the constellations seem to be struck on the inside of a hollow sphere known as the celestial sphere. This sphere appears to rotate around the Earth in an east-west direction every 24 hours. A grid of lines known as right ascension and declination help astronomers locate stars on the celestial sphere, and star maps are a projection of the imaginary sphere onto a flat surface.
Right Ascension (R.A.)
R.A. is one of the co-ordinates used to locate positions on the celestial sphere. Lines run from the North to the South celestial pole and are similar to the Earth's lines of longitude, except that they are measured in units of time.
Declination (DEC.)
DEC. is one of the co-ordinates used to locate positions on the celestial sphere and it is measured in degrees. Lines run from East to West and are linked to the Earth's lines of latitude: stars of 0° Dec., for example, lie in the same plane as the Earth's equator.
Community Feature
Apparent Magnitude
This is a measure of apparent brightness, which is the visible-light brightness of a celestial object observed from Earth, depending on both the distance of the object and its actual or true brightness.
Absolute Magnitude
is the magnitude (visible-light brightness) that a celestial object would have if it were observed at a standard distance of 32.6 light years (10 parsecs). Absolute magnitude differs from apparent magnitude, which is a measure of how bright an object looks to an observer on the Earth.
Astronomers here on Earth use apparent magnitude. The brighter a star is the lower its magnitude, i.e. a star with a magnitude of 1.2 is brighter than one with mag. 3.0, and a star mag. -0.7 is brighter than one of mag. -0.1. During the 18th century the ratio between magnitudes was fixed at 2.5 (2.5118865 to be exact). This means that a star of a given magnitude is 2.5 times brighter than a star one magnitude dimmer.
i za asteroidi:
hmm prviot feniks imase problemi pr isletuvanjeto...dali naovoj site sistemi ke mu istrajat-ama aj da se nadevame vo ime na naukata a i state of the art e.Една од поинтересните работи која не очекува оваа година е лансирањето на вселенското летало Kepler. Ова летало вредно 500 мил. долари на НАСА ке има мисија да зема податоци и слики од ѕвезди и планети во нашата галаксија за кои научниците сметаат дека е можно да има жив свет.
До сега научниците имаат детектирано 322 планети кои кружат околу други ѕвезди но повеќето од нив се гас џинови. За прв пат во историјата ова летало ке може да детектира и помали планети со слична димензија на нашата земја, за кои сметаат дека можеби се населени од жив свет. Ова летало ке користи моќен фотометар кој ке регистрира 100 000 ѕвезди и планети кои се наоѓаат пред нив. Секое најмало прекршување на светлината од планета ке биде регистрирано и ке може да се одреди големината на планетата со огромна прецизност.
Launch date/time: 2009 March 5 at 10:48 pm EST
R
RAYTHEON23
Гостин
It is surprising to many people that radio astronomy does not entail listening for ET to phone home. SETI, (the search for extra terrestrial intelligence), represents a relatively tiny portion of radio astronomy. It would seem that the public perception of radio astronomy conjures up images of astronomers in tight jeans wearing headphones to detect some weak signal buried in the galactic noise. If we apply a brief reality check, we find that radio astronomy is much like optical astronomy, in that telescopes (instruments that detect, image and magnify) are used to observe the cosmos. The difference is that while optical telescopes present images that are familiar in composition (i.e. they present images at frequencies which we can directly see). Radio telescopes observe the cosmos at much lower frequencies. Most of us have seen the stunning images acquired by the Hubble Space Telescope. To be sure these images not only give us a glimpse of the wonders of the universe, but move us in spirit by generating a sense of awe. Unfortunately the primary sensory input device for us humans (our eyes) is very limited in "bandwidth" (the span of electromagnetic frequencies, or 'colours', to which it is sensitive) and while the images move us, they do not give up their secrets easily. As a consequence much of what is happening in the universe is hidden from our view.
To put it simply, each colour is a different frequency, and most of the colour pallet with which the cosmos is painted is invisible to our eyes. It only makes sense to expand our sensitivity, through instrumentation, to the other frequencies in the electromagnetic spectrum. The radio telescope is one of these instruments. It allows us to observe and image the universe at frequencies below our visual abilities which in turn, reveals much of what is going on in the universe. Because certain radio frequencies pass effortlessly through pesky dust and gas clouds we can now study objects heretofore blocked from our view. Also, since certain gases, molecules, and materials in the universe either absorb or emit 'light' at radio frequencies, these structures can be directly viewed by the radio telescope. This ability not only allows the observer to image these objects, but also allows the observer to gather much more information such as composition, velocity, temperature and mass.
The span of frequencies that makes up the radio spectrum is immense, thus the variety and types of instruments that make up radio telescopes is varied in design, size, and configuration. Lower frequency (10 MHz - 100 MHz (wavelengths of 30 meters to 3 meters)) instruments are generally arrays of antennas similar to "TV antennas" or are stationary reflectors of gigantic proportions with moveable focal points some are over 30 meters high by 500 meters wide. At higher frequencies (100 MHz to 1GHz (wavelengths of 3 meters to 30 cm)) very large parabolic or spherical reflectors are used such as the large spherical "Dish" at Arecibo, Puerto Rico. At Frequencies of (1 GHz to 10 GHz (wavelengths of 30 cm to 30 mm)) medium to large parabolic reflectors are used 5 to 90 meters in diameter.
These reflectors are fully articulated and can observe any object simply by pointing the reflector. For frequencies above 10 GHz (wavelengths of 30 mm to .3 mm) high precision parabolic reflectors are necessary typically 3 to 20 meters in diameter. The reflectors are more like mirrors and are thermally stable as well as supported by complex structures since the surface curvature is held to demanding standards. The surface tolerances of these reflectors are held to plus or minus one hundredth of a millimetre for radio telescopes operating in the millimetre to sub-millimetre wavelength region. Each type of instrument opens a new set of "colours" with which for the astronomer may view the universe.
za teleskopite give such clear images since the wavelength of visible light is so small in relation to the diameter of the focusing device (mirror or lens). Radio waves having enormous wavelengths by comparison, do not focus into neat "pictures" rather they tend to interfere with one another since the focusing device (reflector) is tiny in relation to the wavelength. To construct a 10 mm wavelength radio telescope with the imaging capabilities of a small 4 inch optical telescope one would need a reflector about 2 km (over 6000 feet!) in diameter, clearly this enormous size is impractical. It might seem at first glance that radio astronomy would be doomed to low detail observations and rather dull data gathering tasks. The fact that light and radio waves tend to interfere with one another gives rise to a technique known as interferometry. Simply put, it allows two or more dish antennas to be placed widely apart or in arrays (such as the VLA "Very Large Array" in New Mexico) to function as if they were one large antenna (Aperture Synthesis). The interference between the signals of each of the receiving antennas, when timing corrections are introduced, allows for image reconstruction using Fourier Transforms. We can now get the resolution of a 2 km antenna by placing several antennas 2 km apart and correlating the data. Using this technique it is possible to obtain milliarcsecond resolution. A milliarcsecond is roughly the equivalent of seeing a quarter in New York from Los Angeles!
With the advent of DSP (Digital Signal Processing), Faster and Smaller Computers, and the introduction of super conducting amplifiers radio astronomy has progressed at a break neck pace. New arrays of antennas are being designed and built. Some contain over a thousand individual antennas all operating in harmony, giving resolutions that rival optical telescopes. Other arrays cover a hectare and one in process covers a square kilometer as a "phased array" giving imaging capabilities not experienced before. The future for radio astronomy looks brighter than ever.
To put it simply, each colour is a different frequency, and most of the colour pallet with which the cosmos is painted is invisible to our eyes. It only makes sense to expand our sensitivity, through instrumentation, to the other frequencies in the electromagnetic spectrum. The radio telescope is one of these instruments. It allows us to observe and image the universe at frequencies below our visual abilities which in turn, reveals much of what is going on in the universe. Because certain radio frequencies pass effortlessly through pesky dust and gas clouds we can now study objects heretofore blocked from our view. Also, since certain gases, molecules, and materials in the universe either absorb or emit 'light' at radio frequencies, these structures can be directly viewed by the radio telescope. This ability not only allows the observer to image these objects, but also allows the observer to gather much more information such as composition, velocity, temperature and mass.
The span of frequencies that makes up the radio spectrum is immense, thus the variety and types of instruments that make up radio telescopes is varied in design, size, and configuration. Lower frequency (10 MHz - 100 MHz (wavelengths of 30 meters to 3 meters)) instruments are generally arrays of antennas similar to "TV antennas" or are stationary reflectors of gigantic proportions with moveable focal points some are over 30 meters high by 500 meters wide. At higher frequencies (100 MHz to 1GHz (wavelengths of 3 meters to 30 cm)) very large parabolic or spherical reflectors are used such as the large spherical "Dish" at Arecibo, Puerto Rico. At Frequencies of (1 GHz to 10 GHz (wavelengths of 30 cm to 30 mm)) medium to large parabolic reflectors are used 5 to 90 meters in diameter.
These reflectors are fully articulated and can observe any object simply by pointing the reflector. For frequencies above 10 GHz (wavelengths of 30 mm to .3 mm) high precision parabolic reflectors are necessary typically 3 to 20 meters in diameter. The reflectors are more like mirrors and are thermally stable as well as supported by complex structures since the surface curvature is held to demanding standards. The surface tolerances of these reflectors are held to plus or minus one hundredth of a millimetre for radio telescopes operating in the millimetre to sub-millimetre wavelength region. Each type of instrument opens a new set of "colours" with which for the astronomer may view the universe.
za teleskopite give such clear images since the wavelength of visible light is so small in relation to the diameter of the focusing device (mirror or lens). Radio waves having enormous wavelengths by comparison, do not focus into neat "pictures" rather they tend to interfere with one another since the focusing device (reflector) is tiny in relation to the wavelength. To construct a 10 mm wavelength radio telescope with the imaging capabilities of a small 4 inch optical telescope one would need a reflector about 2 km (over 6000 feet!) in diameter, clearly this enormous size is impractical. It might seem at first glance that radio astronomy would be doomed to low detail observations and rather dull data gathering tasks. The fact that light and radio waves tend to interfere with one another gives rise to a technique known as interferometry. Simply put, it allows two or more dish antennas to be placed widely apart or in arrays (such as the VLA "Very Large Array" in New Mexico) to function as if they were one large antenna (Aperture Synthesis). The interference between the signals of each of the receiving antennas, when timing corrections are introduced, allows for image reconstruction using Fourier Transforms. We can now get the resolution of a 2 km antenna by placing several antennas 2 km apart and correlating the data. Using this technique it is possible to obtain milliarcsecond resolution. A milliarcsecond is roughly the equivalent of seeing a quarter in New York from Los Angeles!
With the advent of DSP (Digital Signal Processing), Faster and Smaller Computers, and the introduction of super conducting amplifiers radio astronomy has progressed at a break neck pace. New arrays of antennas are being designed and built. Some contain over a thousand individual antennas all operating in harmony, giving resolutions that rival optical telescopes. Other arrays cover a hectare and one in process covers a square kilometer as a "phased array" giving imaging capabilities not experienced before. The future for radio astronomy looks brighter than ever.
R
RAYTHEON23
Гостин
moznost za kone;no gledanje na temnata materija
When we look at the star filled night sky most of us do not realize we are looking back in time. The stars, planets and other matters in the space separated from us by tens, hundreds and thousands of light years, shows the history of the cosmic objects when the light from it started to travel from it towards the earth. Hidden among the cosmic wonders is the history of the origin of the universe waiting to be unraveled to humankind. It will not be long when astronomers can actually witness the big bang and the beginning of creation of the universe.
Astrophysicists are optimistic that the new technologies will aid them in opening new vistas on the origin of the universe and its complexities. In a series of articles published in the latest edition of Science, leading astrophysicists have explained how new technologies are helping them to unravel the cosmic web theory by which the universe is held together by dark matters.
Dark matters are difficult to be traced, as they do not reflect light waves. New technologies capable of analyzing radio waves are capable of detecting these mysterious dark matters that hold galaxies together with their gravitational attraction. In 2013 James Webb Space Telescope will be launched in the space that scientists expect will help in detecting neutral hydrogen - the remnants of the ingredients from which the first stars were born.
In 2011, the European Space Agency will launch its GALA experiment by which the stars in the universe will be mapped and their motions measured. Another important discovery the astrophysicists are waiting for is the tracking of the cosmic baryons in space using high-resolution ultra-violet optics. Baryons are protons and atomic nuclei that are present in every object big or small from stars to the tiniest insect on earth. The missing baryons will help resolve all arguments on the standard cosmological model.
When we look at the star filled night sky most of us do not realize we are looking back in time. The stars, planets and other matters in the space separated from us by tens, hundreds and thousands of light years, shows the history of the cosmic objects when the light from it started to travel from it towards the earth. Hidden among the cosmic wonders is the history of the origin of the universe waiting to be unraveled to humankind. It will not be long when astronomers can actually witness the big bang and the beginning of creation of the universe.
Astrophysicists are optimistic that the new technologies will aid them in opening new vistas on the origin of the universe and its complexities. In a series of articles published in the latest edition of Science, leading astrophysicists have explained how new technologies are helping them to unravel the cosmic web theory by which the universe is held together by dark matters.
Dark matters are difficult to be traced, as they do not reflect light waves. New technologies capable of analyzing radio waves are capable of detecting these mysterious dark matters that hold galaxies together with their gravitational attraction. In 2013 James Webb Space Telescope will be launched in the space that scientists expect will help in detecting neutral hydrogen - the remnants of the ingredients from which the first stars were born.
In 2011, the European Space Agency will launch its GALA experiment by which the stars in the universe will be mapped and their motions measured. Another important discovery the astrophysicists are waiting for is the tracking of the cosmic baryons in space using high-resolution ultra-violet optics. Baryons are protons and atomic nuclei that are present in every object big or small from stars to the tiniest insect on earth. The missing baryons will help resolve all arguments on the standard cosmological model.
R
RAYTHEON23
Гостин
ete link od zbir na dobri programi hemiski no i molekularen dizajn ima
http://www.mediafire.com/?sharekey=51525e8d03aba98f0f83d91f6dff7c38661d2f7367935c825621d66e282a0ee8:helou:
http://www.mediafire.com/?sharekey=51525e8d03aba98f0f83d91f6dff7c38661d2f7367935c825621d66e282a0ee8:helou:
R
RAYTHEON23
Гостин
aj malce za crnite dupki...
[FONT="]Blackholes "[/FONT][FONT="] [/FONT]
[FONT="]Black holes are objects so dense that not even light can escape their gravity, and since nothing can travel faster than light, nothing can escape from inside a black hole . Loosely speaking, a black hole is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull. Since our best theory of gravity at the moment is Einstein's general theory of relativity, we have to delve into some results of this theory to understand black holes in detail, by thinking about gravity under fairly simple circumstances. Suppose that you are standing on the surface of a planet. You throw a rock straight up into the air. Assuming you don't throw it too hard, it will rise for a while, but eventually the acceleration due to the planet's gravity will make it start to fall down again. If you threw the rock hard enough, though, you could make it escape the planet's gravity entirely. It would keep on rising forever. The speed with which you need to throw the rock in order that it just barely escapes the planet's gravity is called the "escape velocity." As you would expect, the escape velocity depends on the mass of the planet: if the planet is extremely massive, then its gravity is very strong, and the escape velocity is high. A lighter planet would have a smaller escape velocity. The escape velocity also depends on how far you are from the planet's center: the closer you are, the higher the escape velocity . The Earth's escape velocity is 11.2 kilometers per second (about 25,000 M.P.H.), while the Moon's is only 2.4 kilometers per second (about 5300 M.P.H.).We cannot see it, but radiation is emitted by any matter that gets swallowed by black hole in the form of X-rays. Matter usually orbits a black hole before being swallowed. The matter spins very fast and with other matter forms an accretion disk of rapidly spinning matter. This accretion disk heats up through friction to such high temperatures that it emits X-rays. And also there is some X-ray sources which have all the properties described above. Unfortunately it is impossible to distinguish between a black hole and a neutron star unless we can prove that the mass of the unseen component is too great for a neutron star. Strong evidence was found by Royal Greenwich Observatory astronomers that one of these sources called Cyg X-1 (which means the first X-ray source discovered in the constellation of Cygnus) does indeed contain a black hole. It is possible there for a star to be swallowed by the black hole. The pull of gravity on such a star will be so strong as to break it up into its component atoms, and throw them out at high speed in all directions. Astronomers have found a half-dozen or so binary star systems (two stars orbiting each other) where one of the stars is invisible, yet must be there since it pulls with enough gravitational force on the other visible star to make that star orbit around their common center of gravity and the mass of the invisible star is considerably greater than 3 to 5 solar masses. Therefore these invisible stars are thought to be good candidate black holes. There is also evidence that super-massive black holes (about 1 billion solar masses) exist at the centers of many galaxies and quasars. In this latter case other explanations of the output of energy by quasars are not as good as the explanation using a super-massive black hole. A black hole is formed when a star of more than 5 solar masses runs out of energy fuel, and the outer layers of gas is thrown out in a supernova explosion. The core of the star collapses to a super dense neutron star or a Black Hole where even the atomic nuclei are squeezed together. The energy density goes to infinity. For a Black Hole, the radius becomes smaller than the Schwarzschild radius, which defines the horizon of the Black Hole: The death explosion of a massive star, resulting in a sharp increase in brightness followed by a gradual fading. At peak light output, supernova explosions can outshine a galaxy. The outer layers of the exploding star are blasted out in a radioactive cloud. This expanding cloud, visible long after the initial explosion fades from view, forms a supernova remnant. So, a black hole is an object, which is so compact that the escape velocity from its surface is greater than the speed of light. The following table lists escape velocities and Schwarzchild radii for some objects: The black hole masses ranging from 4 to 15 Suns (1 solar mass = 1 Msun = 2 x 1033 grams.) And are believed to be formed during supernova explosions. The after-effects are observed in some X-ray binaries known as black hole candidates. The velocity depends on the mass of the planet. The scientists believe if our Sun dies, the sun may turn into a black hole. Black holes were theorized about as early as 1783, when John Michell mistakenly combined Newtonian gravitation with the corpuscular theory of light . The concept of an escape velocity, Vesc, was well known, and even though the speed of light wasn't, Michell's idea worked the same. He showed that Vesc was proportional to mass/circumference and reasoned that, for a compact enough star, Vesc might well exceed the speed of light. His mistakes were twofold: he subscribed to the corpuscular theory of light, and he assumed that Newton's law of universal gravitation could apply to such a situation. These mistakes happened to cancel each other out, but when the wave theory of light gained favor, the astronomers abandoned these dark stars. In the beginning of the 20th century, Einstein proposed his theory of general relativity. The formula worked out by Michell and rederived, this time without mistakes in the derivation, by Karl Schwarzschild, gives the Schwarzschild radius for any massive body (that is, a body containing mass): RS= 2GM/c2. Vesc for any body smaller than this radius would exceed that of light, and since general relativity forbids this; any matter within RS would be crushed into the center. Thus RS can effectively be thought of as the boundary of a black hole, called an event horizon because all events within RS are causally disconnected from the rest of the universe. There aren¡¦t many physical features of a black hole. In an aphorism coined by John Wheeler , "black holes have no hair," hair meaning surface features from which details of it's formation might be obtained. There are no perturbations in its event horizon, no magnetic fields. The hole is perfectly spherical and in fact has only three attributes: it's mass, it's spin (angular momentum), and it's electric charge. Of these properties, it is only the mass that concerns astronomers. As a cloud of gas contracts, the interior heats up until the core is so hot and dense that nuclear reactions can occur. This nucleosynthesis of hydrogen into heavier elements generates a tremendous pressure, according to the ideal gas law P=NkT, and this pressure holds the star up against further gravitational collapse. This state of equilibrium, during which a star is said to be on the main sequence, lasts until the hydrogen in the core is used up, about 10 billion years for a star like the sun, whereupon gravity will resume shrinking the star. Exactly what occurs next depends on the complicated interactions between different layers of the star, but generally, the star will explode in a supernova. If there is any remnant of this explosion, its further evolution depends almost exclusively on it's mass. A remnant below ~1.4 M (@) will collapse until it can be supported by electron degeneracy pressure and form a white dwarf. A remnant between ~1.4 and ~3 M(@) is halted by neutron degeneracy pressure and forms a neutron star. Degeneracy pressure is an effect that results from quantum mechanical interactions when the density of subatomic particles increases. As it depends only on this density, it is non-thermal and will remain no matter how much the star cools down. Still for remnants above ~3 M(@), not even degeneracy pressure can counter the force of gravity, and a black hole is born. This was the general base that general relativity gave to astronomers, but just because something is allowed to happen doesn't mean that it does. Most astronomers resisted such absurd realities. Astronomers are very conservative by nature, and some of the most respected and influential astronomers of the day rejected this idea so soundly that it wasn't until the 60's that any actual searches began. At first, the only instruments available were the old familiar optical telescopes. Optical telescopes are just what they sound like, telescopes sensitive to the visible portion of the electromagnetic spectrum . [/FONT]
[FONT="]Blackholes "[/FONT][FONT="] [/FONT]
[FONT="]Black holes are objects so dense that not even light can escape their gravity, and since nothing can travel faster than light, nothing can escape from inside a black hole . Loosely speaking, a black hole is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull. Since our best theory of gravity at the moment is Einstein's general theory of relativity, we have to delve into some results of this theory to understand black holes in detail, by thinking about gravity under fairly simple circumstances. Suppose that you are standing on the surface of a planet. You throw a rock straight up into the air. Assuming you don't throw it too hard, it will rise for a while, but eventually the acceleration due to the planet's gravity will make it start to fall down again. If you threw the rock hard enough, though, you could make it escape the planet's gravity entirely. It would keep on rising forever. The speed with which you need to throw the rock in order that it just barely escapes the planet's gravity is called the "escape velocity." As you would expect, the escape velocity depends on the mass of the planet: if the planet is extremely massive, then its gravity is very strong, and the escape velocity is high. A lighter planet would have a smaller escape velocity. The escape velocity also depends on how far you are from the planet's center: the closer you are, the higher the escape velocity . The Earth's escape velocity is 11.2 kilometers per second (about 25,000 M.P.H.), while the Moon's is only 2.4 kilometers per second (about 5300 M.P.H.).We cannot see it, but radiation is emitted by any matter that gets swallowed by black hole in the form of X-rays. Matter usually orbits a black hole before being swallowed. The matter spins very fast and with other matter forms an accretion disk of rapidly spinning matter. This accretion disk heats up through friction to such high temperatures that it emits X-rays. And also there is some X-ray sources which have all the properties described above. Unfortunately it is impossible to distinguish between a black hole and a neutron star unless we can prove that the mass of the unseen component is too great for a neutron star. Strong evidence was found by Royal Greenwich Observatory astronomers that one of these sources called Cyg X-1 (which means the first X-ray source discovered in the constellation of Cygnus) does indeed contain a black hole. It is possible there for a star to be swallowed by the black hole. The pull of gravity on such a star will be so strong as to break it up into its component atoms, and throw them out at high speed in all directions. Astronomers have found a half-dozen or so binary star systems (two stars orbiting each other) where one of the stars is invisible, yet must be there since it pulls with enough gravitational force on the other visible star to make that star orbit around their common center of gravity and the mass of the invisible star is considerably greater than 3 to 5 solar masses. Therefore these invisible stars are thought to be good candidate black holes. There is also evidence that super-massive black holes (about 1 billion solar masses) exist at the centers of many galaxies and quasars. In this latter case other explanations of the output of energy by quasars are not as good as the explanation using a super-massive black hole. A black hole is formed when a star of more than 5 solar masses runs out of energy fuel, and the outer layers of gas is thrown out in a supernova explosion. The core of the star collapses to a super dense neutron star or a Black Hole where even the atomic nuclei are squeezed together. The energy density goes to infinity. For a Black Hole, the radius becomes smaller than the Schwarzschild radius, which defines the horizon of the Black Hole: The death explosion of a massive star, resulting in a sharp increase in brightness followed by a gradual fading. At peak light output, supernova explosions can outshine a galaxy. The outer layers of the exploding star are blasted out in a radioactive cloud. This expanding cloud, visible long after the initial explosion fades from view, forms a supernova remnant. So, a black hole is an object, which is so compact that the escape velocity from its surface is greater than the speed of light. The following table lists escape velocities and Schwarzchild radii for some objects: The black hole masses ranging from 4 to 15 Suns (1 solar mass = 1 Msun = 2 x 1033 grams.) And are believed to be formed during supernova explosions. The after-effects are observed in some X-ray binaries known as black hole candidates. The velocity depends on the mass of the planet. The scientists believe if our Sun dies, the sun may turn into a black hole. Black holes were theorized about as early as 1783, when John Michell mistakenly combined Newtonian gravitation with the corpuscular theory of light . The concept of an escape velocity, Vesc, was well known, and even though the speed of light wasn't, Michell's idea worked the same. He showed that Vesc was proportional to mass/circumference and reasoned that, for a compact enough star, Vesc might well exceed the speed of light. His mistakes were twofold: he subscribed to the corpuscular theory of light, and he assumed that Newton's law of universal gravitation could apply to such a situation. These mistakes happened to cancel each other out, but when the wave theory of light gained favor, the astronomers abandoned these dark stars. In the beginning of the 20th century, Einstein proposed his theory of general relativity. The formula worked out by Michell and rederived, this time without mistakes in the derivation, by Karl Schwarzschild, gives the Schwarzschild radius for any massive body (that is, a body containing mass): RS= 2GM/c2. Vesc for any body smaller than this radius would exceed that of light, and since general relativity forbids this; any matter within RS would be crushed into the center. Thus RS can effectively be thought of as the boundary of a black hole, called an event horizon because all events within RS are causally disconnected from the rest of the universe. There aren¡¦t many physical features of a black hole. In an aphorism coined by John Wheeler , "black holes have no hair," hair meaning surface features from which details of it's formation might be obtained. There are no perturbations in its event horizon, no magnetic fields. The hole is perfectly spherical and in fact has only three attributes: it's mass, it's spin (angular momentum), and it's electric charge. Of these properties, it is only the mass that concerns astronomers. As a cloud of gas contracts, the interior heats up until the core is so hot and dense that nuclear reactions can occur. This nucleosynthesis of hydrogen into heavier elements generates a tremendous pressure, according to the ideal gas law P=NkT, and this pressure holds the star up against further gravitational collapse. This state of equilibrium, during which a star is said to be on the main sequence, lasts until the hydrogen in the core is used up, about 10 billion years for a star like the sun, whereupon gravity will resume shrinking the star. Exactly what occurs next depends on the complicated interactions between different layers of the star, but generally, the star will explode in a supernova. If there is any remnant of this explosion, its further evolution depends almost exclusively on it's mass. A remnant below ~1.4 M (@) will collapse until it can be supported by electron degeneracy pressure and form a white dwarf. A remnant between ~1.4 and ~3 M(@) is halted by neutron degeneracy pressure and forms a neutron star. Degeneracy pressure is an effect that results from quantum mechanical interactions when the density of subatomic particles increases. As it depends only on this density, it is non-thermal and will remain no matter how much the star cools down. Still for remnants above ~3 M(@), not even degeneracy pressure can counter the force of gravity, and a black hole is born. This was the general base that general relativity gave to astronomers, but just because something is allowed to happen doesn't mean that it does. Most astronomers resisted such absurd realities. Astronomers are very conservative by nature, and some of the most respected and influential astronomers of the day rejected this idea so soundly that it wasn't until the 60's that any actual searches began. At first, the only instruments available were the old familiar optical telescopes. Optical telescopes are just what they sound like, telescopes sensitive to the visible portion of the electromagnetic spectrum . [/FONT]