Why do stars seem small when seen from the Earth?
148618
Not only are they very far away, but a good deal of the stars we see are already dead. All we are actually seeing is the light that they let off. Eventually that light will go away too, but because it is so far away, it took the light from one of those stars millions of years just to get to where it is now.
752575
The scientific name for the twinkling of stars is stellar scintillation (or astronomical scintillation). Stars twinkle when we see them from the Earth's surface because we are viewing them through thick layers of turbulent (moving) air in the Earth's atmosphere. \n\nStars (except for the Sun) appear as tiny dots in the sky; as their light travels through the many layers of the Earth's atmosphere, the light of the star is bent (refracted) many times and in random directions (light is bent when it hits a change in density - like a pocket of cold air or hot air). This random refraction results in the star winking out (it looks as though the star moves a bit, and our eye interprets this as twinkling). \n\nStars closer to the horizon appear to twinkle more than stars that are overhead - this is because the light of stars near the horizon has to travel through more air than the light of stars overhead and so is subject to more refraction. Also, planets do not usually twinkle, because they are so close to us; they appear big enough that the twinkling is not noticeable (except when the air is extremely turbulent). \n\nStars would not appear to twinkle if we viewed them from outer space (or from a planet/moon that didn't have an atmosphere). \n\n\n---------------------------------------------------------------------------------\nStars, except for the Sun, although they may be millions of miles in diameter, are very far away.  They appear as point sources even when viewed by telescopes.  The planets in our solar system, much smaller than stars, are closer and can be resolved as disks with a little bit of magnification (field binoculars, for example).\n\nSince the Earth's atmosphere is turbulent, all images viewed up through it tend to "swim."  The result of this is that sometimes a single point in object space gets mapped to two or more points in image space, and also sometimes a single point in object space does not get mapped into any point in image space.  When a star's single point in object space fails to map to at least one point in image space, the star seems to disappear temporarily.  This does not mean the star's light is lost for that moment.  It just means that it didn't get to your eye, it went somewhere else.\n\nSince planets represent several points in object space, it is highly likely that one or more points in the planet's object space get mapped to a points in image space, and the planet's image never winks out.  Each individual ray is twinkling away as badly as any star, but when all of those individual rays are viewed together, the next effect is averaged out to something considerably steadier.\n\nThe result is that stars tend to twinkle, and planets do not.  Other extended objects in space, even very far ones like nebulae, do not twinkle if they are sufficiently large that they have non-zero apparent diameter when viewed from the Earth.\n-------------------------------------------------------------\n\n\nI can be more specific, sure. Remember that just like a computer screen, your eye is composed of a certain number of "pixels," each represented by a single light-receptor cell in your retina. If two (or more) points of light are close enough such that they are focused on the same receptor cell in your eye, you will experience them as a single point of light. This is referred to as the "resolution" of your eye, or any telescope for that matter. \n\n\nNow, a star on the sky is in a true sense a single point of light. All the light comes through the atmosphere in exactly the same direction, through exactly the same atmospheric turbulence, and thus is bent in exactly the same way. So when it gets to your eye, the amount of light you see coherently varies. It also strikes (primarily) only a single receptor in your eye. \n\n\nOn the other hand, light from a planet is different. Each of a few receptors in your eye sees a large number of light rays coming f
931172
Because we are really close to our star, the sun.  The light from it drowns out the other lights from stars.  The same way a very small light in a room is drowned out by turning on a much larger one.  At night, we are completely turned away from it, so we can now see other lower light sources.
75380
There is a surprisingly simple answer to your great question: Each month we see different stars, so to answer for a specific night of the year at your specific location on Earth depending on your eyesight and how bright the city lights around you are might be hard to pin down. \n However there is a magnitude scale that astronomers use to describe how bright objects in the sky are. Without getting into details on how that works, the average human being can see down to about magnitude 6 ( brighter objects have lower magnitude until you reach zero. Then even brighter objects use negative numbers for their magnitudes which is a bit weird, isn't it?) Therefore, all you have to do is get a map of the whole sky showing anything brighter than magnitude 6 and count the stars. If you are fortunate to be away from bright city lights and you can see the Milky Way, you would be really surprised to know that you can only see about 6,000 stars. That's the number of stars above magnitude 6 in the entire sky.
264522
The healthy human eye is only restricted by external factors (ie.: poor visibility due to haze, dust or fog), just think how far the stars are!
575563
If it's perfectly flat (Remember the earth is curved), you can see forever.. Stars are a LONG way away, and there is a plane (ok an infinate numbers of planes) that connect you and that star.. Which is the same as "perfectly flat" ground.\n\nNow, Seriously:\nFor someone who is 5' 4" (eyes 5 feet from the gorund) you can see: 3.0097474977147174 miles.\n\n-HtJ
496226
STARS AND NEBULAE.\n\nMost of the things you can see in the night sky are stars: a few thousand are visible to the unaided eye. A star is a hot ball of mostly hydrogen gas; the Sun is an example of a typical, ordinary star. Gravity keeps the gas from evaporating into space, and pressure due to the star's high temperature and density keeps the ball from shrinking. In the core of the star, the temperature and densities are high enough to sustain nuclear fusion reactions, and the energy produced by these reactions works its way to the surface and radiates into space as heat and light. When the fuel for the fusion reactions is depleted, the structure of the star changes. The process of building up heavier elements from lighter ones by nuclear reactions, and adjusting the internal structure to balance gravity and pressure, is called stellar evolution. \nLooking at a star through a telescope can tell us many of its important properties. The color of a star tells us its temperature, and the temperature depends on some combination of the star's mass and evolutionary phase. Usually, observations also allow us to find the luminosity of the star, or the rate at which it radiates energy as heat and light. \nAll stars visible to the unaided eye are in our galaxy, the Milky Way. The Milky Way is system of roughly 100 billion stars, along with a great deal of interstellar material. The galaxy is shaped like a flattened disk embedded in a round, faint halo. Gravity keeps the stars from drifting away, and the motions of the stars keep the system from falling in on itself. The Milky Way has no distinct edge - the distribution of stars tapers off gradually with increasing distance from the center. The SDSS detects stars more than a million times fainter than can be seen with the unaided eye, far enough to see the outer structure of the Milky Way. \nStar Colors and Luminosities: The H-R Diagram\nAstronomers often make plots of the luminosities of stars compared to their colors. The first such charts were made in the early twentieth century, when astronomers took spectra of thousands of stars, then placed the spectra into a sequence based on the appearance of several different features. The classes of stars were given different letters as names; in order of decreasing temperature, they are OBAFGKMLT. The hottest stars are class O, while the coolest are class T. Two astronomers, Ejnar Hertzsprung and Henry Norris Russell, independently started to wonder what would happen if they compared stars' luminosities to their spectral classifications (or, alternatively, to their temperatures). They knew that some stars were hotter and more luminous than the sun, and that others were cooler and less luminous. Hertzsprung and Russell found that 90% of the stars fell into a narrow band they termed the "main sequence." Today, we call this type of plot a Hertzsprung-Russell (or H-R) diagram. \nAstronomers further divide each letter into ten categories from 0 to 9, with 0 being the hottest star in that spectral class and 9 being the coolest. So, a B1 star is hotter than a B2 star, and a B9 star is hotter than an A0 star. Our own sun is at the "hot" end of the G range with a surface temperature of 5,770° K; therefore, it's called a G2 star. \nSpectral classes give us a convenient way to refer to most types of stars - from O0, the hottest at over 25,000° K, down to T9, the coolest failed stars at 1,000° K. Each spectral type of star is associated with a specific color: all G-type stars like the sun are yellow, all M-type stars appear red, and all B-type stars are bluish. Thus, this system of letters and numbers tells us where a star is on the horizontal (color or temperature) axis of the H-R diagram. \nTwo alternative systems tell us approximately where on the vertical (luminosity) axis a star can be found. One system uses absolute magnitude, a measure of luminosity derived from the apparent magnitude, or brightness of the star
1010582
it is the difference in brightness between the stars and any astronaut, cosmonaut, space shuttle, or international space station.  the stars are just too dim.  a much longer exposure time is needed to photograph dimmer objects.  ask someone who knows about photography.\n\nhttp://en.wikipedia.org/wiki/Photography
401971
when the light from the stars enter the earth's atmosphere, the light wave bends and refracted until it reach our eyes. So because it is refracted, when we look at it, it seems to be twinkling.
468156
Most--not all--shooting stars (meteors) are about the size of a grain of sand. Most of these specks are left-over material from comets that have passed in and out of the inner solar system.\n\nGod should be spelled B-I-G B-A-N-G\nPBrax@netscape.com
629239
because the earths atmosphere acts like a lens, so the lower the sun or moon to the horizon then the larger they appear :)
484123
At the half way point Alpha Centauri would be a little brighter, but not much brighter, and the Sun would look like a bright star, but not the brightest one in the sky. In other words, it would look just like night time on Earth when the sky is very clear and very dark, for example from a remote mountain top.
205942
Bigger that what? \n\nRemember, these planets are still a long ways away. \n\nAnd the morning star/evening star, which is Venus, sometimes called Lucifer or Hesperides or Phosphorus or Hesperus (The identification of morning star with evening star, or Phosphorus=Hesperus was famously realized by Pythagoras) is very large and bright in the sky sometimes. \n\nMercury is a bit harder to see because it is so small, and so close to the sun.
184581
there are places where there are no stars, just because they can be so far apart, and there are also stars that are so far away, or not very bright that can't be seen from earth, then of course there's all that light pollution that blocks many stars from being seen - go to a city ur lucky if u see one, but out in the country........ its beautiful
700811
This is because the earth is so large - relatively - as compared to our size. While standing on the earth, we are unable to see the change in slope of the earth's surface. Our line of sight will make it seem as if the earth is flat, but our sight is really a tangent, being very close to the line of the earth's surface. An example of this is when look out at the ocean, and see the masts of a ship first in the distant horizon. This is because at that distance, the curve of the earth is more prominent.
56614
The pictures taken in space are (usually) taken through a very small aprature and have a very short depth of field.  That means they're not focusing on the background at all.  Because of this, the light of the stars is often too dim to be sceen by the camera, especially when there's a bright object in frame. (The Earth, a lit astronaut, space shuttle, ect.)\n\nI can't respond again, so I'm editing this one.\n\nTo the girl below me, I think your answer is well incorrect.  The distance from Earth to state is 60,000 miles.  The stars are light years away.  From Earth to near space is such a small distance coparitively is like saying that standing in New York, you'll be able to see a movie screen in San Fransico easier if you jump up and down.
77735
Some stars might have a solar system, but not all do.  Some stars are actually two "suns" orbiting around one another (called a binary star) but appearing to the unaided eye as a single star.  Some are even three stars together, such as alpha centauri, which is the closest "star" in the sky--though it is actually three stars that look like one.  Some are stellar clusters, where many of these "suns" are all bunched close enough to appear as one star.  Some are entire galaxies, with billions of stars, but so far away that they appear to be a single star from earth.  Some are stellar clusters, where many of these "suns" are all bunched close enough to appear as one star.\n\nSome things you might think are stars are actually planets.\n\nSome are dead "suns," where the fuel for the nuclear fusion that makes the sun burn has all been expended, leaving a big mass of iron, that glows white-hot for many years before turning dark.  If you look at these so-called "white dwarves" through a powerful telescope, you can see a faint ring of matter that has been blown away in the explosion that came when the star died.  Some stars are huge, and some are small.\n\nSome of the stars we have been able to see have solar systems of their own, which we detect by the slight wobble caused by the gravitational pull of the planet (or planets) as it orbits.