What is the galactic fountain model?
357831
The galactic fountain model is a model of gas enrichment in the galaxy.  It holds that when supernova go off near the top or bottom of the galactic disk the enriched gas they blow off sprays above and below the disk.  This gas then falls back into the galactic disk and helps to enrich the gas there.  \n\nIn short the model is that huge bubbles of superheated gas from supernovae burst open, shooting gaseous plumes 20,000 light-years out from the galaxy’s disk. (One light-year equals about 5.8 trillion miles.) As the gas cools, it loses buoyancy and crashes back onto the galaxy itself at speeds exceeding 100,000 miles per hour.
759202
Ok, how about this:\n\nAstronomers estimate that there are at least 70 sextillion (7×10^22) stars in the known universe. That is 230 billion times as many as the 300 billion in our own Milky Way.\n\n(shamelessly stolen from Wikepedia)
761942
http://www.amazon.com/Cosmos-Carl-Sagan-Jarom%C3%ADr-Hanzl%C3%ADk/dp/B000055ZOB
5355
No one knows.\n\nThere are about 10 planets in our solar system, depending on whom you ask.\n\nAround 100 planets have been detected in other solar systems.\n\nThere are at least 200 billion stars in the Milky Way Galaxy (ours).\n\nIf the average number of planets per star is 10, then there are 2000 billion or 2 trillion planets in our galaxy.\n\nNo one knows how many billion galaxies are in the Universe.
446996
Do you mean SPIRAL galaxies?\n\nCompare the Milky Way (our "spiral" galaxy) with others in the universe. There's a classification for spirals, so it shouldn't be that hard to write a paper on it (without be a physicist)
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?
685302
Number of intelligent species in our galaxy =\nN x fp x Ne x fl x fi\n\nWhere \nN=the number of star in our galaxy\nfp=the fraction of stars that have planetary systems\nNe=the number of planets in a given system that are suitable for life\nfl=the fraction of otherwise suitable planets on which life actually arises\nfi=the fraction of inhabited planets on which an inteligent form of life evolves\n\nYou'll have to guess some of the figures for the equation but why bother, some scientists have already had a go.\n\nIt turns out that there should be intelligent life somewhere within 200 light years of earth. However.......\n\nThat intelligent life may not yet have evolved.\n\nLife on this planet started over 200 million years ago (probably longer) Human like species only started kicking about around a million years ago.\n\nWe only really got serious technology wise about 3000 years ago, and start transmitting radio waves of any strenght detectable from a distance around 60 years ago.\n\nThere is certainly life out there. Where, how inteligent and more importantly WHEN is anybodies guess.\n\nHope this helps
113742
No one can say for certain. Matter of fact we don't know exactly how many stars there are in our own Milky Way Galaxy. Most guestimates for the Milky Way run to about 250-billion stars. Then there are about 250-billion other galaxies in the observable universe, each with more or less 250-billion stars each. A reasonable ball park figure for total number of stars in the observable universe would be approximately---approximately!---   5^22. That's 5 followed by 22 zeros.
425839
Well I found this really cool map a while back. It's not from a reliable Star Wars source (i.e. www.starwars.com or www.theforce.net) but it looks pretty good. Check it out.\n\nThe second one is almost exactly (if no exactly) the same. \n\nI don't know if this is what you wanted, but it's something.
104087
Have a look here,\nhttp://outreach.physics.utah.edu/labs/star_life/starlife_main.html
37458
The "universe" is filled with galaxies. We're in the milky way. If you buy into star trek, the milky way is divided into four quadrants - the alpha, beta, gamma, and delta.  Earth would be near the border of the Alpha and Beta quadrants.  Then you shrink down further to the star systems - an area around a single or binary sun, which includes any orbiting planets. Then you get to the planet level, divided up by countries, then states, provinces, and municipalities, cities and towns, then finaly, me, you, and all these other people.
606528
200 billion stars in the Milky Way.
599588
Well it is a spiral galaxy, but it is a kind of cool one.  It is a little difficult to tell from inside the disk, but it looks like we live in a barred spiral galaxy.  \n\nNot one with a huge bar, like this one: (http://antwrp.gsfc.nasa.gov/apod/ap050112.html) \n\nbut kind of a medium bar like this one:\n\n(http://antwrp.gsfc.nasa.gov/apod/ap041216.html).\n\nSeen edge on it looks like this far-far-far infrared picture:\nhttp://antwrp.gsfc.nasa.gov/apod/ap950908.html\n\nThat is real data taken from earth orbit, so you can see why it is hard for us to see if there is a bar. We surmise the bar from the velocity distributions of gas and stars towards the center.\n\nSo that is what it looks like.  In proportion, star wise, you can imagine the central bulge as the size of a hard boiled hens egg yolk, and the disk about the dimensions of a CD. Yeah, VERY thin. there is no edge, the stars just kind of peter out.  Also, the center is mostly old small reddish stars, and the arms are domininated light wise by young blue short lived stars. There is a thicker disk of fainter red old stars too. \nMost of the gas and dust is in the disk and a ring around the bar.  This is where all the star formation goes on. \n\nI could go on for pages more...but that should be enough to get you to ask more focussed questions.
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.
592779
Big bottle of champagne. We and all the galaxies are bubbles released when the bottle was oppened then the gravitational force will bring us back in. Where and who and what is this bottle?????????????
59422
Our “address” is: \n\nThe third planet of the star “Sol”, which is the name of the sun. \n\nSol is about 27,000 light years from the center of the Milky Way galaxy, on the inner rim of the “Orion Arm”. The Milky Way galaxy—our galaxy—has four “spiral arms”. An “arm” of a galaxy is a very huge arc of stars that extend out from the center of the galaxy in a long spiral. \n\nThe "Milky Way" galaxy is in the “Local Group”. Galaxies are clustered into groups of galaxies, with wide areas of semi-nothingness between the groups. We have named the group of which our galaxy is part the “Local Group” for obvious reasons. \n\nThe “Local Group” is part of the “Virgo Supercluster”. A supercluster is a cluster of groups of galaxies. \n\nThe “Virgo Supercluster” is one of many clusters and superclusters in the known universe. There is no “official name” of our universe, since it is the only universe of which we know. It is therefore usually just called “the universe”. \n\nOur address is therefore the third planet of the star Sol, on the inner rim of the Orion Arm of the Milky Way galaxy, in the Local Group of galaxies, within the Virgo Supercluster, in "the universe". \n\nNow that you know the address, from whom are you expecting mail?
148399
A real good question, but one that I've never seen any kind of discussion about. It would be close to impossible to determine our Sun's galactic orbit because there are just too many variables involved that would periodically change the orbit--gravitational disturbances by other stars, galaxies, and varying densities as we traverse the spiral arms, etc.,. Also, it takes our Sun some 250-million years to make one complete orbit and we haven't been around long enough to get any kind of reliable idea of current orbital parameters.