1 What is a true relashionship  between a light year anad a parsec ?
2 How many stars are there in our universe ?

Asked by satenderc | 8th Jun, 2014, 11:06: AM

Expert Answer:

1. A light year is the distance covered by light in one year at the speed of 300,000 kilometres per second.
A parsec is the short of parallactic second,it is an astronomical unit of length used to measure distances to objects outside the solar system.
It is the distance at which an arc of length one astronomical unit subtends an angle of one second of an arc.
1 parsec= 3.26163626 light years
1 light year = 0.30659458 parsec.
2. Stars are not scattered randomly through the space, they are gathered together into vast groups known as galaxies. The Sun belongs to a galaxy called the Milky Way.
Astronomers believe that there are about 100 thousand million stars in the Milky Way galaxy alone. Outside that, there are millions upon millions of other galaxies also.
Estimating the number of stars within it requires knowing just how big the universe is.For the Universe there are something like 1011 to 1012 stars in our Galaxy,
and there are perhaps something like 1011 or 1012 galaxies.
With this calculation we can say that there are about 1,000,000,000,000,000,000,000 stars in space, or about 10 raised to the 21 power, roughly.It is not an accurate value.

Answered by Jyothi Nair | 9th Jun, 2014, 09:18: AM

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