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100
A star is a gaseous self-luminous body in space.
What is a star?
100
No, only about 250 of the brighter stars have names.
Do all of the stars have names?
100
The Babylonians were probably the first historical people to name the stars. Most of the names which have come down to us are Arabic, with some Persian, Greek, Latin and Babylonian names. Most of the Latin names are modern. The names of the stars came to us about 2,000 years ago. Some of them came 500 years ago.
How did the stars get their names?
100
Which is the second nearest? The Sun is the nearest the Earth. The mean distance of the Sun from the Earth is 150 million kilometers. The distance from the Earth to the second nearest star, Proximate Centauri, is about 4.2 light years from the Sun. That distance translates into 40 billion (40,000,000,000,000) kilometers.
What star is nearest the Earth?
100
The distances to the nearer stars are measured mathematically, by trigonometric parallax. "Parallax" is a word of Greek origin meaning difference in the apparent positions of an object.
How are the distances to the near stars measured?
200
The word "parsec" is made up of the parts of the words "parallax" and "second". It means the distance from the Earth to a star whose parallax is one second of arc. There is no star as near as one parsec, for the parallax of the nearest star is 0.75". A parsec is 3.26 light years.
What is a parsec?
200
A man can see between 3,500 and 4,000 stars.
How many stars can we see on a clear night?
200
In general, a star's brightness depends upon its distance from us, its temperature and its size. With stars of the same size and temperature, the nearer stars will appear to be the brighter. With stars at the same distance and of the same size, the hotter stars will be the brighter. With stars at the same distance and the same temperature, the larger stars will appear brighter.
Why are some stars brighter than others?
200
Magnitude is the measure of the brightness of a star or of any luminous body in the heavens.
What does magnitude mean?
200
Magnitude is the measure of the brightness of a star or of any luminous body in the heavens.
What does magnitude mean?
300
Yes. The colors most often seen in the stars are red, orange, yellow, white and blue. There are some violet stars and a few green stars.
Do the stars have color?
300
Yes. Colors indicate star temperatures, they also tell which of the elements make up the stars. As a rule, the blue and the white stars are the hottest, while the red stars are cooler stars.
Do the colors of the stars have any significance?
300
The hottest stars have a surface temperature about 45,000°C. The coolest visible stars are about 200°C at their surfaces. The inside temperatures of all stars must be measured in the millions of degrees.
How hot are stars?
300
An instrument called a thermonuclear indicates the amount of radiation we receive from a star.
How do we know the temperature of a star?
300
The smallest known stars are about the size of planets. The largest stars are hundreds of times the diameter of the Sun.
How big are stars?
400
A giant star is one whose diameter is between 10 times the diameter of the Sun and 100 times its diameter.
What is a giant star?
400
The largest star masses known are only 100 times the mass of the Sun, and such stars are very rare. The giants are large, cool stars, whose masses are about the mass of the Sun and go from 10 and sometimes 20 times of the Sun's mass.
Are the giants massive stars?
400
Stars which are larger than giants are super-giant stars. A super-giant star is one whose diameter is more than 100 times the diameter of the Sun.
What is a super-giant star?
400
The masses of the super-giants are 30 times the mass of the Sun, although, the volumes of such stars may be thousand of times the volume of the Sun.
Are the super-giants massive stars?
400
No, as a rule, the super-giant stars are all of a low surface temperature - about 3,000°C.
Are the super-giant stars hot stars?
500
The largest stars are about 3,000 times the diameter of the Sun. In kilometers, this is from about 5 thousand million kilometers in diameter to about 160 million kilometers.
What are the sizes of the super-giant stars?
500
There is no limit to the number of stars in a cluster. Some galactic clusters have few stars. Some of the great globular clusters have many hundreds of thousands of stars.
How many stars are there in a cluster?
500
Variable stars are stars whose brightness is not constant, but whose light changes from time to time.
What are variable stars?
500
In the list of the 20 brightest stars, seven are double stars.
Are there many double stars?
500
Yes. There are several stars which have become nova more than once.
Has any star ever become a nova more than once?
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