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How many stars observable to the naked eye are in the universe?
In general terms, with people of normal vision, there are in total around 8,000 stars observable with the naked eye. This breaks down to 4,000 in the north, and 4,000 in the south, non-overlapping. But in the north, for example, half the stars in your year-round sky are obscured by the sun; so roughly 2,000 stars are visible, on average, in the nighttime sky on any night. And this assumes very good viewing conditions. This may not sound like a very high number, but we have become used to hearing astronomical things described with correspondingly huge numbers. Try coming up with a method of estimating the number of stars you actually see; you probably won't be too far off from 2,000 if you do it carefully. We are talking about stars in the Milky Way; a small number of galaxies and clusters can be seen as 'stars' with the naked eye, but no stars outside of the Milky Way are observable..
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It isn't possible to put an exact number to it, because it all depends on the amount of light pollution, other pollutants and the state of your eyes. An average person will …be a able to see about 2,000 stars, the top limit around 5,000.
About 6000, under very good viewing conditions. Of these, about half (3000 stars) are above the horizon at any one moment. Since there is a lot of extinction (reduction in bri…ghtness) for stars near the horizon, the actual number you can see is somewhat less, even under the best viewing condition.
The most recent estimates place the number of stars in the observable universe at around 1023. That's a 1 with twenty-three zeros after it. More precisely, that would be 100 s…extillion. "The universe is so big, it doesn't even make sense to talk about how big it is."
The Betazoids. Councelor Diana Troi (TNG) is a Betazoid for instance.
at least 100 billion or more.
There are perhaps something on the order of 1080 atoms in the observable universe, or at least that is a figure that seems to be tossed around a bit. A link can be found below…. We know that 1 mole of hydrogen is 1 gram, which has 6.022 x 10^23 atoms in it. We can easily approximate 1 kilogram (1000 grams) of any material to 1000 moles, since all atoms are based on the hydrogen model multiplied by X number of times corresponding to their atomic number. So, for example, although 1 kg of Iron is not 1000 moles, as Hydrogen is, but about 20 moles, one mole of Iron has 26 protons (29 neutrons) and 26 electrons, and has about 26 times the mass of hydrogen. So 1 kg of Iron is about 6.022x10^23 * 20 = 1.2 x 10^24 ~ 10^24 atoms, this is not far from 10^26 hydrogen's atoms. The most common element and atom in the universe is hydrogen anyway. Therefore 1 kg of any material can reasonably be approximated to about 1000 moles, which is about 6.022 x 10^26 atoms, or about 10^26 atoms per kilogram of mass in the universe. Earth has ~ 6 x 10^24 kg of mass. This is, 6 x 10^24 * 6 x 10^26 (number of atoms in 1 kg of substance) about 3.6 x 10^51 atoms or roughly 10^51 atoms. Now this might seem like very close to 10^80 atoms, but it is not. It would take approximately 10^30 Earths to reach that number, which is far more than our Galaxy has in mass. Our Galaxy has 1.4 x 10^42 kg of mass, which is about 10^45 moles. Multiplying that times Avogado's number (6.022 x 10^23, or about 10^23) we get 10^68 atoms in the Milky Way. There are 125 billion galaxies in the observable universe, which is 1.25 x 10^11, which is approximately 10^11 galaxies. From that: 10^68 * 10^11 we get 10^79, or about 10^80 atoms (10^78 if we count atoms as heavy as Iron, above which the universe does not naturally make on any grand scale; it goes up to Uranium, which is about 5 moles/kg) in the observable universe, with about as many electrons (1 hydrogen atom as per our model has 1 proton and 1 electron). ---- A second way is to use the known length of the observable universe. The observable universe is about 93 billion light years. Taking the volume of the universe as a sphere: 4/3*pi*R^3, the volume of the universe would be: (4/3)*3.141592*46.5^3 = ~ 4.2 x 10^23 cubic lightyears as the volume of the observable universe. Knowing that the universe is about 0.0000000000000000000042 percent matter, multiplying 4.2 x 10^23 by that gives us ~ 1.77 cubic lightyears of matter. 1 lightyear is 10 trillion kilometers, which is 1 million trillion centimeters or 10^18 cm in 1 lightyear. 1 cubic lightyear would then be (10^18)*(10^18)*(10^18)=10^54 cubic centimeters in 1 cubic lightyear so about 1.77x10^54 cubic cm of matter in the universe. It's estimated that there are about 10^17 atoms in an average cubic centimeter, so 1.77x10^54 * 10^17 = 1.77 x 10^81 which is about 10^81 atoms in the universe
thay have no eyes the see by their other senses.
In a solar eclipse there are three stages, the beginning, the total eclipse and the end. during the total eclipse the sun is totally covered and during this time your iris ope…ns up totally to have a brighter view in the dark and when the eclipse passes this stage, sun's radiation enter your eyes and since the iris is totally opened, yours eyes get damaged.
Answer 1: Hundreds of billions of billions. Updated: As of 2009, it was estimated to be around 1023 stars in the observable universe. However, it was recently discovered… that we may have been missing most stars of the red dwarf variety and now it is beginning to look like the 1023 figure would now have to be tripled. So its about.... 3,000,000,000,000,000,000,000,000
700 million billion billion or 700,000,000,000,000,000,000,000,000
This is a difficult question to answer because what star is visible to the naked eye depends on many factors: 1. Viewing conditions for that particular night (e.g. clouds, e…xcess light) 2. Time of viewing (the earth moves so stars dip below the horizon as time passes) 3. The Earth's position in it's orbit around the Sun can make some stars harder to see. So I'll answer your question based on the common constellations that are generally visible to most people from most places on Earth. So take for instance the "asterism" The Big Dipper (Part of the Constellation Usra Major). It's one of the most famous and easily recognizable group of stars in the sky, and one of it's stars called "Dubhe" is 123.78 Light years away from us. That means the light from Dubhe takes 123yrs to reach us. In other words if Dubhe blew up we wouldn't know for 123yrs. In the constellation "Orion" the star Alnilam is about 1359 Light years from us. In Canis Major a star Aludra is about 3000 light years away. So this is like a way of going back in time since you are seeing the star as it WAS in the past. These stars were not formed 3000yrs ago obviously. Some of the stars are 100's of millions of years old or more. You can check other constellations and their component stars to find out which are the farthest and the approximate time when they might have been formed. Many stars were formed BILLIONS of years ago after the big bang. Though it's hard to know how old a star is exactly we can guess it's approximate age based on it's metal content. Of course using the logic above it's easy to say that our own Sun would be the oldest easily visible star. Most stars are about 1Billion -10Billion years old HE 1523-0901, is an estimated 13.2 billion years old, and is the oldest star discovered. It was one of the early stars to develop after the big bang. But this is not something you will see from your back yard on a clear night.
Stars which are RED are cooler stars than the blue one, so Yes it is possible to distinguish coller stars by the naked eye. Star Betelgeuse is called Ardra in Indi…an-Astronomy. Ardra in sankrith means wet. Betelgeuse is one of the red star and cooler than other blue stars. I only wonder, how ancient people could have imagined this star could be cooler than others and name it as Ardra !
What other instruments are used by the scientist to observe objects which cannot be seen by the naked eye?
There are two: Tycho Brahe, whose detailed observations aided Kepler's discoveries of the laws governing the planetary orbits, working in the 16th century before the use o…f telescopes, and William Herschel, whose systematic catalog of thousands of non-stellar objects is essentially still used today, working roughly 200 years later with telescopes of his own design and manufacture. Since nearly all serious astronomy, even among amateurs, is now done with cameras of various sorts, no one is likely to match their achievements with the naked eye.
The answer has to be estimated; for many reasons no one can ever know the exact numbers, whatever that might mean in this context. Estimates of the number of galaxies in the u…niverse range from about 170 billion to one trillion. One trillion is one thousand millions. Estimates of the number of stars range from around 70 sextillion to 300 sextillion. Seventy sextillion is 7 followed by 22 zeros. 300 sextillion is 3 followed by 23 zeros. Some estimate as high as 10 to the power 24, which is one followed by 24 zeros. You might think that 22, 23 and 24 are small numbers here, until you begin to consider that every single one of them represents a power of ten. The number is far beyond anything that any human mind can grasp on anything close to a practical level.