a dark interstellar globule is about the same size as what?
109136
They are about 100 AU in size.
307862
If you look at the sky on a clear night, away from city lights and polluted air, you'll see a milky band of light right across the sky, the Milky Way, our galaxy.   With a small telescope you'll see the milkiness is made of individual stars.You're looking at the plane of ourgalaxy.   If you look away from this band of light you're looking out into intergalactic space away from the thickness of our galaxy so you don't see so many stars.   If you look in the direction of the constellation Sagittarius, you'll see the Milky Way seems to get wider and brighter.   This is the centre of the galaxy.   So the galaxy is shaped like two dinner plates facing each other, circular, and fatter at the centre than at the edges.   The centre is bright because stars are packed closer together there than way out here.   We know that we're about 30 000 light years from the centre, the diameter of the galawy is about 100 000 light years and the thickness at the centre is about 3000 light years because a particular type of star called a Cepheid variable gets brighter and dimmer with a period that depends on how bright it is.   So we know how bright it really is.   By measuring how bright it appears, we can work out haw far away it is.   So by looking at Cepheids in different parts of the galaxy we can work out its measurements.   And if we look at other galaxies outside our own, many of them are the same shape; fat in the centre, thin at the edges, with spiral arms curving out from the centre, like cloud bands in a hurricane.
1009893
It is possible that the class of giant gas planets might merge into brown dwarfs at the upper end of the scale. However, a brown dwarf, while it does not have enough internal pressure to fuse hydrogen into helium, can fuse deuterium.  There's not much deuterium, so they don't burn very brightly or for very long, but this brief burst of fusion power makes them stars of a sort. \n\nBrown dwarfs range in size from about .013 solar mass (~13x the mass of Jupiter) to .08 solar mass.  Smaller bodies might be planets, slightly larger bodies are red dwarf stars.
761942
http://www.amazon.com/Cosmos-Carl-Sagan-Jarom%C3%ADr-Hanzl%C3%ADk/dp/B000055ZOB
252206
I believe the correct term that you are looking for is "dark matter".\nConsider this: If all of space is filled with very bright stars, then why is it mainly dark.\nScientists came up with the theory of "dark matter", theoretical matter that absorbs the brightness of the stars.\nHowever, my theory is that space is just so completely vast and the stars are so far apart that there is just not enough light to fill it.\nConsider this: you are standing in the middle of a large room with no light. You take out a flashlight...how far can you see? It depends on the size of the room, right. If it is a small room, then the light beam from your flashlight may be able to reach one wall of the room...but say this room is very very large. Would you be able to see the wall then, considering you are standing in the middle of the room?\nSpace has no walls or boundaries...how far would your flashlight see then?...\nSo that's the "dark matter" theory and my theory.\nCiao!
546765
Greetings,\n\nDark matter doesn't have to be dark.  It's called dark matter because we don't know what it is.\n\nCurrent cosmological theories regarding the expansion of the universe and accelleration of that expansion tell us there is matter and energy we have not accounted for or discovered yet.\n\nBlack holes fall into matter we have, for the most part, accounted for.\n\n-matt
194430
A Star's Size:\n\nA star begins its "life" in a contracting nebula of gas and dust. As the density of the material increases under the influence of gravity, compression heats the material. If the material gets hot enough, hydrogen atoms begin fusing together to form helium atoms, and a star is born. A star will spend most of its life, called the main sequence phase, fusing hydrogen into helium.\n\n  \nIt's logical that a large nebula (one with a large amount of mass) will form a large star, and a small nebula will form a small star. However, in addition to a star's initial mass, a star's size also depends on the balance between the inward pull of gravity and the outward push of the energy produced by fusion. The entire sequence of a star's evolution can be described in terms of the changing balance between these two opposing forces.
9076
The density of a gas and dust in a random part of space in our galaxy is so low that on Earth our best attempts to create a vaccum are much more dense.\n\nThe average density of space is about 1 atom per cubic centimeter (more or less the size of a sugar cube) although it can vary from one tenth of that to "dense" regions with 1000 atoms per cubic centimeter.
451952
Gravitational attraction between all the gas and dust in a nebula, and maybe their electrical charges too.\n\nGod should be spelled B-I-G B-A-N-G\nPBrax@netscape.com
913686
This is a simple ratio problem. The equation would be Dgalaxy/Dearth=Dearth/x so x=(Dearth)^2/Dgalaxy. Asssuming a parsec is 3.6 light years, and a light year is 5.87 trillion miles and the diameter of the Earth is 8,000 miles, then the Earth would be 0.001 millimeter or one micron in size, which is the size of an average bacterium, maybe? Very cool. Oops! I re-did my calculation and I see that I made a factor of ten error. The correct answer is about 0.1 microns, or the size of some viruses. But tell me how you would make such a model of the Earth?
128460
It might be, or it might be a neutron star. We do not really know. \n\nThere are some other objects in the sky which are much more certainly black holes, from their masses and other properties.
571914
there are stars out there that haven't been discovered yet.  There is a finite amount of atoms in a grain of sand.  The period at the end of this sentence can hold about 250,000 atoms across.  So a grain of sand would have less atoms than there are stars in the universe.
395085
yeh, a meteorit and a galaxy are coming to earth. Don't worry, they come only after 2 milion years...;))
67634
Despite the large amount of knowledge we now have about the Andromeda Galaxy, its distance, though among the best known intergalactic distances, is not really well-known. While it is well established that M31 is about 15-16 times further away than the Large Magellanic Cloud (LMC), the absolute value of this measure is still uncertain, and in current sources, usually given between 2.4 and 2.9 million light-years - a consequence of the uncertainty in the LMC distance and thus the overall intergalactic distance scale. E.g., the semi-recent correction from data by ESA's astrometrical satellite Hipparcos has pushed this value up by more than 10 percent, from about 2.4-2.5 to the about 2.9 million light-years we use here.
550266
It is expanding to the point of dark matter.  Then it will contract back into itself.  Then it was start all over again.  This is from the my interruption of the Kaballah.
864425
One source that breaks down these classifications by temperature, or maybe it was only color photometry (I don't recall) is Kenneth Lang's Astrophysical formula:\n\nhttp://www.amazon.com/Astrophysical-Formulae-Radiation-Processes-Astrophysics/dp/3540296921/sr=1-1/qid=1163374728/ref=sr_1_1/102-7735916-8685767?ie=UTF8&s=books\n\nVolume I has some tables I think you will find helpful.  You might need to do a little interpolation...\n\nanother place to look would be the iau website http://www.iau.org . The IAU is the kind of group that would define a standard, though this might be too detail oriented for them to mess with.\n\nYou will be hard pressed to find an equation, however.  You are going to be stuck with a lookup table.
1153702
Dark energy comprises 70% of the universe and dark matter comprises 26% of the universe. Ordinary baryonic matter, in the form of gas and stars, only makes up 4%.\n\nDark matter refers to matter particles, of unknown composition, that do not emit or reflect enough electromagnetic radiation to be detected directly, but whose presence may be inferred from gravitational effects on visible matter such as stars and galaxies. Dark matter is explained as being cold, non-baryonic, collision-less dust.\n\nDark energy is a hypothetical form of energy which permeates all of space and has strong negative pressure. According to the theory of relativity, the effect of such a negative pressure is qualitatively similar to a force acting in opposition to gravity at large scales. In other words, dark energy acts as a repulsive force or anti-gravitation and is responsible for the acceleration of the universe.