Why can't we determine the distances to galaxies using triangulation, as we do for stars?
917628
Because Galxies are constantly in motion and moving threw the cosmic void as if right now the nearist galaxie to our galaxie the andormeda is moving at 400000 mph towards the mliky way at about 100 million years they will colide in a so caleld ," Death Dance " and merge into a super galaxie the most common unit of mesuarment for space is the A.U. or the astronomical unit and since the sun wich is a star is locked in place and is not moving unlike galaxies and there is a  massive black hole at the center of the mily way atracting andromeda and it is coming towards us the stars stay fixerd unlike galaxies so it would be impractical because we would never have accurate data since the variables and mesaurments are allways changing for galaxies but do to stars they are not that is why. hope that was helpful.
342181
Well the nearest star system is light years away. So if they send one, we won't find out the findings. Besides, how would we send commands and receive them, they would have to travel light years of distance. So I would say no.
1157446
The reason nothing is sent out from earth up or down is rather simple, Nothing is within reach in those directions. For the most part the planetary system; the only thing we are able to explore at current technology level, is on a flat planer system due to the suns gravity force. Certainly the universe is tri-dimensional but it is A: very hard to depict in that way. and B: Impossible for us to study in terms of anything besides telescope observation.
42286
Astronomers use parallax to measure the distance to a star. They also use this method to measure the distance galaxies. For more information see link below.
1010059
Farther than they really are? FARTHER?\n\nI just can't imagine the distance that they actually are away. Can you really "see" a dstance of several lightyears? And that is just the distance to our "next neighbours".\n\nIf you can estimate that distance with your bare eye I'll promise you a brilliant career in astrophysics!
354744
This is a great question, actually, and one that bothered astronomers for centuries.  In short, there’s no simple way to measure the distances to planets—at least not without really good telescopes (and a bit of luck).\n\nIn the early 17th Century, Kepler devised his Third Law, which releated the distance of a planet from the Sun and the time it took to revolve around the Sun.  So if you know one interplanetary distance, you can figure out the rest.  Which is all well and good, except that there were no good distances at the time.  (A rough sense of the distance between the Sun and Earth constrained the numbers somewhat, but the estimates were pretty far off—Kepler thought the Solar Syatem was about one seventh its actual size.)\n\nThe first accurate means of determining the distances was by observing transits of Venus across the face of the Sun.  Through relatively simple trigonometry, one can calculate the actual distances between the Sun, Venus, and Earth.  Unfortunately, transits don’t occur very frequently, so it was only in the 19th Century that reasonable results were achieved.\n\nNowadays, the distances to planets are determined by bouncing radar off them.  Because we know how fast light travels, we can simply measure the time between emitting a radio pulse and its return back to Earth, which gives us the distance!  Easy as pie…\n\n(In the case of the Moon, we actually bounce lasers off a reflector left there by Apollo astronauts.  Because of the phase information of the laser light, we can get extremely accurate distances to our nearest neighbor.  That’s how we confirmed that the Moon is moving away from us at the rate of about 3.8 centimters per year.)\n\n\nRyan Wyatt\nRose Center for Earth & Space\nNew York, New York
481919
It is impossible to trisect an arbitrary angle using only compass and straightedge (but bisection is possible). No there is no mathematical technique (i.e a theoretical construction technique to do so, even if impractical). It cannot be done exactly. The best that can be done is approximation. One can imagine, I suppose, a radial arm (our radius rotating about a fixed  point) whose rotation speed was controlled very precisely by a computer and the speed could be extremely slow and a laser could be used with a super accurate quartz timer to 'print' a dot at fixed intervals thus dividing an arbitrary angle as desired. Certainly, technologically feasible, but I haven't heard anything about it, and it would be a technological technique, not a mathematical "breakthrough".
527724
All stars except the Sun appear to the human eye as shining points in the night sky that twinkle because of the effect of the Earth's atmosphere. Interferometer telescopes are required in order to produce images of these objects. The Sun is also a star, but it is close enough to Earth to appear as a disk instead, and to provide daylight.\n\nStars are not spread uniformly across the universe, but are typically grouped into galaxies. A typical galaxy contains hundreds of billions of stars. The majority of stars are gravitationally bound to other stars, forming binary stars. Larger groups called star clusters also exist.\n\nAstronomers estimate that there are at least 70 sextillion (7×1022) stars in the known universe [1]. That is 70 000 000 000 000 000 000 000, or 230 billion times as many as the 300 billion in our own Milky Way.\n\nThe nearest star to the Earth, apart from the Sun, is Proxima Centauri, which is 39.9 trillion kilometers, or 4.2 light years away (light from Proxima Centauri takes 4.2 years to reach Earth). Travelling at the orbit speed of the Space Shuttle (5 miles per second -- almost 30,000 kilometers per hour), it would take about 150,000 years to get there. Distances like this are typical inside galactic discs, where the Sun and Earth are located. Stars can be much closer to each other in the centres of galaxies and globular clusters, or much further apart in galactic halos.\n\nCheck the wikipedia link below.
1073938
Well dear....we aren't centrally placed in our milky way galaxy.....our solar system lies at a distance of about 30,000 light years from its centre....and we don't know the extremities of our universe yet hence our position with respect to the universe can't be measured..
117937
Actually you can look at all the other stars in our galaxy and via rather simple mathematics make a point of view outside the galaxy. So, more or less, making a simple computer program for it and feeding it all the coordinates that we have on the other stars, then adding our own star as 0,0,0 and voila - a picture of the galaxy and an arrow pointing at us.
1084274
Every measurement has an uncertainty.  Measuring distance with a laser for example is affected by the wavelength of the laser which can be changed by air density.   Temperature affects the length of all materials.  Even outer space has distortions due to gravity of the stars and planets, gas clouds etc.
417578
"Astronomers can use parallax to find distances to objects much farther even than planets. To calculate the distance to a star, astronomers observe it from different places along Earth's orbit around the Sun. If they measure the object's position several months apart, their "two eyes" will have a separation of well over 100 million miles! \n\nNow astronomers have technologies to measure distances to other planets more directly. When we have a spacecraft at another planet, we know the time it takes a radio signal to travel between Earth and the spacecraft. We can also send a powerful radar signal toward a planet and time how long it takes for the echo to return. Astronomers know how fast these signals travel (the speed of light), so measuring how long they take makes it easy to calculate the distance very accurately."
1057880
It's possible, but very, very unlikely.  Even when two galaxies "collide," stars do not hit each other.  The distance between stars is much, much, much larger than the diameter of a star.  It's kind of like two cars driving toward each other, only one is in New York and the other is in L.A.  It's possible that they will collide, but it's very unlikely.
70857
everything is related to each other if u know the mass, temperature or type of star it is then by using the russell-hertzsprung diagram u can figure out the luminosity
666465
There are a couple of ways. One uses diffraction effects or speckle interferometry to estimate the angular size of the star. Once the distance to the star is known, the actual size can be determined fairly easily. This method can only be used for very large stars (such as red giants) or very near stars.\n\nFor other stars, we determine the temperature of the star via the spectrum. This tells how bright the star is per unit area. Then, we look at the distance and apparent brightness to determine how bright it is overall. Dividing will give the surface area of the star, and hence its size. The difficult here is that the temperature of the 'atomosphere' is usually much higher than the surface of the star and this can significantly affect the estimates. Also, if the star isn't spherical (because of rotation, for example), the surface area alone won't give all the information about its size that might be desired.
1161939
This is difficult to answer.  Is there a galaxy destroyed everytime I clean my fingernails?\n\nI don't feel we have a good measure of what a galaxy is, our galaxy seems huge, yet we know very little about the boundaries (i.e. what if there were another galaxy right next to ours that we could not reach, like we were different slices of bread, intimately close, yet forever separated)
919010
Yes, you are completely right.  This is why astronomy is so important.  By looking at galaxies that are a billion light years away, we are seeing what those galaxies looked like a billion years ago.  Since we can see objects up to 13.7 billion light years away (corresponding to the age of the universe), we can see objects like galaxies as they appeared at a range of times, letting us develop more thorough hypotheses about how the universe itself has evolved, and what might lie in our galaxy's future.