how the distance of stars which are far away is determined using brightness method?
611005
There is no brighness method, the way of finding it out is by parallax, or the cepheid luminosity variable
160778
Twinkle twinkle little star\n\nThere aren't many nursery rhymes about astronomy. But 'twinkle twinkle little star' makes a useful point. We can tell which lights in the night sky are stars because they appear to twinkle. Planets, on the other hand, don't, they shine steadily in the sky.\n\nStars twinkle because they are very far away, and so appear as tiny points of light in our night sky. Some of this light is absorbed by moving air in the Earth's atmosphere, making the star appear to sparkle.\n\nPlanets, like Saturn or Jupiter, don't sparkle. This is because they are a lot closer to the Earth and so they look bigger in our sky than stars.\n\n\nThe Pistol Star is the brightest in the known Universe\n\nRather than being points of light, planets are small discs. As their light is more spread out, even if some of it is absorbed by our atmosphere, some of the light still filters through, so the planet doesn't twinkle. This means that you can tell the difference between a planet and a star without even needing a telescope, just by seeing if it twinkles!\n\nWeighing a star:\n\nAs for 'wondering what they are', starlight also contains an extraordinary amount of information that can answer that very question.\n\nWeighing a star isn't as difficult as it sounds as you don't need an enormous set of cosmic scales, just one equation. The more massive a star is, the more energy it gives off. So first of all, astronomers measure the star's 'luminosity', the rate at which it emits energy. Then they can work out its mass.\n\nMeasuring a star's temperature:\n\nOnce the mass of the star is known, you can calculate the temperature inside its burning core. Stars perform a delicate balancing act between gas pressure pushing outwards and gravity pulling inwards. Mathematical equations can be used to map this. Then by measuring the size and mass of the star, astronomers can calculate the temperature of the core.\n\n\nWhat's inside a star?\n\nEven more incredibly, just by looking at starlight astronomers can discover what a star is made from.\n\nThe light that we see is just one kind of radiation known as 'visible light'. Other kinds include X-rays, ultraviolet, microwaves, radio waves and infrared. Different stars give out varying amounts of these signals, known as their 'spectrum'.\n\nWhen measured, the spectrum appears as a series of bright and dark lines positioned at specific points or 'frequencies'. This is the blueprint of a star and provides a wealth of information about what is happening inside.\n\nAs elements are heated inside the star, they absorb and emit energy, creating a 'blip' in the star's spectrum. So the position and strength of these lines reveal what elements are inside the star. Stars are classified into 'spectral types' according to the shape of this spectrum.\n\nLooking back in time:\n\nAlthough time travel isn't physically possible yet, we can see back in time just by looking out into space.\n\nLight from the Sun takes 8 minutes to reach Earth. So we are seeing what the Sun looked like 8 minutes ago. Alpha Centauri, our nearest stellar neighbour, lags behind by 4.3 years. So, the further we look out into space, the further we are looking into the past.\n\nThe distance that light travels in a year is called a 'light year'. The furthest that astronomers have ever seen are about 12 billion light years away, from a time just after the Big Bang, when the Universe was just a baby.\n\nI hope this helps....\n\nDon
866295
In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standard luminosity distance away from us, in the absence of interstellar extinction. It allows the overall brightnesses of objects to be compared without regard to distance.\n\nThe apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. The brighter the object appears, the lower the numerical value of its magnitude.\n\nThese answers come from Wikipedia:\nhttp://en.wikipedia.org/wiki/Apparent_magnitude\nhttp://en.wikipedia.org/wiki/Absolute_magnitude\nand these sites may have additional info helpful to you.\n\nHope this helps!
661783
Don't you mean 2nd "nearest" star? The Sun of course is the nearest. The 2nd nearest star from the Earth is the Proxima Centauri which is 4.2 light years away.\n\nI think astrologers haven't named or even determined the the farthest and second farthest stars from the Earth.
180255
The only way that I know to do this with a normal telescope is to compare the star with others nearby of known magnitude and try to decide if it's brighter or dimmer until you find the same.\n\nOtherwise you'd need to measure the amount of light that comes from it, and I think you need computers to do that.\n\nThe magnitude scale is exponential, so deciding a magnitude ain't that simple. (ie a star of magnitude +2 is ten times brighter than a star of magnitude +3)
786773
Their distance from the Sun
543022
In order to measure the diameter of a star you really need three pieces of information about the star (1) distance (2) brightness (3) and color.\nStep 1: Scientists can figure out the total power output of the star by knowing its brightness at Earth and its distance. \n\nStep 2: Figure out the surface temperature. The universe really gave scientists a lucky break because stars are fairly predictable objects. What I mean is that, for most stars once a scientist know one property of the star they can generally figure out everything else they want to know about it. This is because stars behave like "black bodies". This is a physics term which describes how an object of certain temperature glows at different wavelength (thus influencing its color). Most ordinary matter resembles a black body (has nothing to do with being black, it's just terminology). You probably already have an intuitive understanding of this from your everyday experience. For example, when you heat up an object, at first it might start to glow red. And as it gets hotter it might start to glow yellow, blue, and eventually white. Because stars approximate black bodies very well, by knowing the color of the star scientist can figure out what its surface temperature is quite accurately. \n\nStep 3: Another great thing about black bodies is that, for any specific amount of surface area astronomers can predict exactly how much light it will radiate (hotter objects are brighter). And since they already know the temperature and the total brightness of the star they can figure out its surface area, and thus it's diameter :)
818301
It's the distance light travels in a year, ie about\n\n5,878,625,373,183.61 statute miles.\n\n(Based on a reference year of exactly 365.25 days (each of exactly 24 hours). This is the value recommended by the International Astronomical Union. It is not a universal standard.)
174626
Basically, it's the degree of brightness of a star.\n\nThe websites below might be able to help you with your question.
671170
Are you including the stars that are being created, as well as those that do not actually exist anymore but have died out/ supernova'd/ etc. that we are just still seeing since the light has to travel so far?  \n\nI would be interested in how you determined this number ^_^
801074
Let x = distance of object from stronger source. If weaker source has strength S then stronger source has strength 3S.\n\nIllumination due to stronger source is 3S/x².\n\nIllumination due to weaker source is S/(12-x)².\n\nRequired to minimize the total illumination\n 3S/x² + S/(12-x)², or ignoring S, minimize \n\n          t(x) = 3/x² + 1/(12-x)².\n\nDo the usual t '(x) = 0 and check t '' > 0. After simplifying t '(x) = 0 get\n\n          3 (12 - x)³ = x³\n\nTake cube roots and simplify to get\n\n          x = 12 / [ 1 + 1 / 3^(1/3) ]\n\nand on further simplification\n\n          36 / ( 3 + 9^(1/3) ) = 7.086497 feet\n\nYou can check the answer using WIMS Function calculator and selecting "curve"
604131
Extrapolate the formula, using the surface temoerature, and instead of the earth distance, substitute the distance you want to caluclate the temperature at.  \n\n\nMeasuring the Sun's Temperature\nOne method, called Wien's law, uses the wavelength of the peak emission, wavelengthpeak, in the Sun's continuous spectrum. The temperature in Kelvin = 2.9 × 106 nanometers/wavelengthpeak.\n\nAnother method uses the flux of energy reaching the Earth and the inverse square law. Recall from the Stellar Properties chapter that the flux is the amount of energy passing through a unit area (e.g., 1 meter2) every second. From the Inverse Square Law of Light Brightness, you find that the solar flux at the Earth's distance = the Sun's surface flux × (Sun's radius/Earth's distance)2 = 1380 Watts/meter2. Since the Sun's photosphere is approximately a thermal radiator, the flux of energy at its surface = sigma × (the Sun's surface temperature)4, where sigma is the Stefan-Boltzmann constant. Rearranging the equation, the photosphere's temperature = [(solar flux at Earth)/sigma) × (Earth distance/Sun's radius)2]1/4.\n\nThese two methods give a rough temperature for the Sun of about 5800 K. The upper layers of the photosphere are cooler and less dense than the deeper layters, so you see absorption lines in the solar spectrum. Which element absorption lines are present and their strength depends sensitively on the temperature. You can use the absorption line strengths as an accurate temperature probe to measure a temperature of about 5840 K. \n\nRead the link, you'll have to scroll down to come up to the stuff I have cut and paste above.\nst\nHope you find this useful.
541140
Well if you look at the spectrum of a star you'll see a smooth continuum as well as the spectral lines.  Those lines are either absorbtion lines or emission lines of such things as Hydrogen, Helium, Calcium, Iron and a whole heap of others and we know the wavelength of those lines very well so by comparing what we measure them to be with what we have determined in the lab we can calculate how fast the star is moving towards or away us (radial velocity).\n\nThen once we know the radial velocity we just measure where the peak in the continuum is, correct for the radial velocity to find what the wavelength where the emission actually peaks and then since the star is very close to a blackbody we can calculate the temperature (a blackbody of a given temperature will peak at a given wavelength).
581211
Astronomers determined the size and shape of our galaxy and measured distances to other stars using the “parallax method” (and eventually other methods using the star’s light spectrum).  Unfortunately, these methods do little to help us find out the exact distance to our very own star, the Sun.  Surprisingly, to get the distance to the sun, astronomers first had to determine the exact distance to Venus!\n\nWith the invention of radar, scientists were able to measure the distance to Venus very precisely.  By timing how long it took the radar beam to travel at the speed of light to Venus and back, the total distance to the object can be determined from the equation:\n\nDistance = (Speed of Light) X (Total Time)/2\n\nThe reason the total time is divided by two is to get just the distance from the Earth to the object.\nEarth-Sun Distance = (Earth-Venus Distance) / (Cos q)\n\nUsing trigonometry, astronomers now know that the “Astronomical Unit” = 92,955,820.5 miles (149,597,892 kilometers).  This incredible degree of accuracy is possible because the speed of light is known very precisely and extremely accurate clocks are used to time the radar reflection.  Radar can’t be used to determine the distance to the Sun directly because the Sun doesn’t have a solid surface to reflect the radar efficiently.
670041
There are a few measurements that astronomers/cosmologist use to describe the great distances of space.\n\nHere are a few:\n\nLightyear - The distance that light travels in a vacuum in one year, approximately 9.46 trillion (9.46 × 10^12) kilometers or 5.88 trillion (5.88 × 10^12) miles. \n\nAstronomical Unit - A unit of length used in measuring astronomical distances within the solar system equal to the mean distance from Earth to the sun, approximately 150 million kilometers (93 million miles).\n\nParsec - A unit of astronomical length based on the distance from Earth at which stellar parallax is one second of arc and equal to 3.258 light-years, 3.086 × 10^13 kilometers, or 1.918 × 10^13 miles.
1017822
stars are very far away and that light u see has been traveling through space for maybe decades now and its passed through clouds of dust and a bunch of stuff.  That makes the star twinkle and gives it colors.  Also, stars are not white(unless they are white dwarfs, but those arnt really stars or they are really really big and hot).  Almost all stars have a color to them.  These can be blue, red, yellow, orange, or any of those colors inbetween.
430231
The nearest star, the Sun, is 93 million miles from earth. The second closest, Proxima Centauri, is a small, red star at 4.2 light years.