how many stars r in the universe?
364385
Stars are not scattered randomly through space, they are gathered together into vast groups known as galaxies. The Sun belongs to a galaxy called the Milky Way. Astronomers estimate there are about 100 thousand million stars in the Milky Way alone. Outside that, there are millions upon millions of other galaxies also!  \n \n  \n \n \n Hipparcos mapped millions of stars in our galaxy, but how many more are there? \nIt has been said that counting the stars in the Universe is like trying to count the number of sand grains on a beach on Earth. We might do that by measuring the surface area of the beach, and determining the average depth of the sand layer. \n\nIf we count the number of grains in a small representative volume of sand, by multiplication we can estimate the number of grains on the whole beach. \n\nFor the Universe, the galaxies are our small representative volumes, and there are something like 1011 to 1012 stars in our galaxy, and there are perhaps something like 1011 or 1012 galaxies. \n\nWith this simple calculation you get something like 1022 to 1024 stars in the Universe. This is only a rough number, as obviously not all galaxies are the same, just like on a beach the depth of sand will not be the same in different places. \n\nNo one would try to count stars individually, instead we measure integrated quantitites like the number and luminosity of galaxies. ESA's infrared space observatory Herschel, to be launched in 2007, will make an important contribution by 'counting' galaxies in the infrared, and measuring their luminosity in this range - something never before attempted.
1007479
Yes.  Beyond our own Milky Way galaxy there are estimated to be 200 billion more galaxies in the visible universe at distances up to 13 billion light years from Earth.
224500
Wikipedia claims that the observable universe contains about 7 × 1022 stars, organized in about 100 billion galaxies, which themselves form clusters and superclusters. An Ask the Scientist response to this question claimed that there are about 10 billion (10^10) stars in an average galaxy, \nand there are about 10 billion galaxies that we can observe in the universe, so the answer is 100 billion billion or 10^20. I don't think it is an issue that we have a precise answer for as yet.
662250
The number I usually see quoted is 4000, but checking with Google.....\n\nFrom my suburban location, without optical aid, I can see down to about magnitude 5 on a really good night around 2am when there's little traffic and stores are closed.  That's about 2822 (actually less, since  I never see some southern hemisphere stars).  In my binoculars, I see down to magnitude 8, or 77,627 stars.\n\nNow, out in the country, a person with good eyes on a dark clear night can see down to magnitude 6, which is 8768 stars total.   A person with a 6-inch refractor telescope can see down to about magnitude 13, which gives 15,431,076 stars.\n\nOn the other hand, I read a book by an astronomer who said he could see down to magnitude 8 on top of Mauna Kea breathing oxygen from a tank.  That's 77,627 stars with no optical aid.\n\nNow-- for stars seen and unseen, there are about 400 billion stars in our galaxy.  \n\nIn the known universe?  The CNN story linked below says 70 sextillion.  That's 7 with 22 zeros.\n\nIn the whole universe, known and unknown?  Nobody knows--we do not even know if the universe is finite or infinite.  The number could be "infinity".
277935
A galaxy is a huge gravitationally bound system of stars, interstellar gas and dust, plasma, and (possibly) unseen dark matter. Typical galaxies contain 10 million to one trillion (107 to 1012) stars, all orbiting a common center of gravity. In addition to single stars and a tenuous interstellar medium, most galaxies contain a large number of multiple star systems and star clusters as well as various types of nebulae. Most galaxies are several thousand to several hundred thousand light years in diameter and are usually separated from one another by distances on the order of millions of light years.\n\nAlthough so-called dark matter appears to account around 90% of the mass of most galaxies, the nature of this unseen components is not well understood. There is some evidence that supermassive black holes may exist at the center of many, if not all, galaxies.\n\nIntergalactic space, the space between galaxies, is filled with a tenuous plasma with an average density less than one atom per cubic meter. There are probably more than a hundred billion (1011) galaxies in the visible universe.
1046416
Let's assume that by "known Universe" we're talking about the observable Universe. That is a sphere 14.5 billion light-years in radius. \n\nOne light-year is 9.46 x 10^12 km or 9.46 x 10^18 mm. So 14.5 billion light years is 1.37 x 10^29 mm, which is the radius of the Observable Universe. Applying the formula for the volume of a sphere (v = 4/3 pi r^3), we find that the Observable Universe has a volume of:\n\n1.08 x 10^88 cubic millimeters. Which is the number of grains of sand you'd need.
604824
The astrobiology folks at NASA have calculated that there are between one and thirty billion habitable planets in our Milky Way Galaxy.  If our solar system is typical,  you can multiply that by about 10 to get total planets: between 10 and 300 billion.  \n\nSo where is everybody?
491513
During clear night, there are about 6000 (six thousand) visible stars from each hemisphere of the Earth. However, it is for sure that there is no certain way of calculating the exact number of "stars up there", because of explosions of old stars and creations of new stars, that occur almost every minute, somewhere in the universe.
300537
There is disagreement over whether the universe is indeed finite or infinite in spatial extent and volume. Many astronomers and cosmologists believe the universe is infinite due to recent findings in NASA's WMAP project supporting a flat (therefore infinite) universe\n\nHowever, the observable universe, consisting of all locations that could have affected us since the Big Bang given the finite speed of light, is certainly finite. The edge of the cosmic light horizon is 13.7 billion light years (4.19 Gpc) distant. The present distance (comoving distance) to the edge of the observable universe is larger, due to the ever increasing rate at which the universe has been expanding; it is estimated to be about 78 billion light years (7.8 × 1010 light years, or 7.4 × 1026 m). This would make the comoving volume, of the known universe, equal to 1.9 × 1033 cubic light years (assuming this region is perfectly spherical). The observable universe contains about 7 × 1022 stars, organized in about 100 billion galaxies, which themselves form clusters and superclusters. The number of galaxies may be even larger, based on the Hubble Deep Field observed with the Hubble Space Telescope. The Hubble Space Telescope discovered galaxies such as Abell 1835 IR1916, which are over 13 billion light years from Earth.\n\nBoth popular and professional research articles in cosmology often use the term "universe" when they really mean "observable universe". This is because unobservable physical phenomena are scientifically irrelevant; that is, they cannot affect any events that we can perceive.
556954
there are nine planets in the solar system. it is not know yet how many planets are there in the entire universe, because we just know about 3 galaxies (and still do not know about any planets in galaxies other than the milky way)
370961
go to\nhttp://en.wikipedia.org/wiki/Universe
763882
A galaxy is a swirling collection of stars. our own Milky Way galaxy contains hundreds of billions of stars, of which our sun is only one amongst these billions and billions.\n\nA solar system is just a single sun that has planets revolving around it. A galaxy is made up of billions of such suns. And some scientists believe that as many as 25% of the stars could have planets. That means billions and billions of solar systems in our own galaxy.\n\nHere'a a picture of our closest neighbor, the Andromeda galaxy. It has close to one-trillion stars.\n\nHope this heolps. Cheers\n\nhttp://en.wikipedia.org/wiki/Andromeda_Galaxy
838886
That covers only one Galaxy - Milky Way\nThe whole universe is yet to be discovered .... by humans
440062
The universe contains approximately  200,000,000,000,000,000,000 (200 BILLION BILLION) stars in galaxies scattered throughout the universe.  Our solar system is located in one of the spiral arms of the Milky Way galaxy.  The Milky Way galaxy contains approx. 200,000,000,000 stars.  \n\nThe universe is the largest of the three organizational structures in your question.  \n\nHope this helps!
1126282
Consider this there are billions upon billions of stars in each galaxy we are just 1 galaxy and there are billions upon billions of galaxy's in the universe. So the question should start with the universe.
219187
I do.  There are at least 7*10^22 or 70000000000000000000000 stars out there, so how could anyone really think that only one of those stars have life.  It has been estimated that there are about 1 billion planets with life on them in the entire universe.
820280
There are about 2800 stars that can be seen with the naked eye, if the conditions are ideal (no light pollution, super dark night with clear sky, and assuming you can only see part of the sky as a big part is on the other side of the planet) see link #1.\nHowever, if you want to know how many are there that could be visible if you had the most powerful telescope anyone can imagine, then the number is a bit more: 70 sextillion (see link #2).\nOur galaxy, the Milkyway, contains about 100 billion stars, and there are more galaxies in the universe than there are stars in a galaxy.