Galaxies are the group of billions of stars held together by the force of gravity.Most are either spiral or elliptical,but some are irregular in shape.
The Milky way
This is the best known galaxy.The word galaxy comes from the Greek for milk.Before telescopes were powerful enough to prove that they were made up of individual stars,galaxies look like milky or cloudy areas in the sky .Our solar system is only one of 100-200 billion stars in the Milky way,which is 100,000 light years in diameter.The Sun and all the planets take about 200,000,000 years to complete one orbit around its center.
Brightest- The large Magellanic Cloud which is visible only in the southern hemisphere is 170,000 light years from earth and 39,000 light years in diameter.
Largest- The central galaxy of the Abel 2029 galaxy cluster was discovered in 1990.It is 1070 million light years distant and has a diameter of 5.6 million light years,80 times the diameter of our own galaxy.It has a total light output equivalent to 2 trillion times that of the Sun.
Nearest - Discovered in 1993, the Canis Major Dwarf galaxy is approximately 25,000 light years from the solar systems.
Sources: Whitakers's world of facts
The Milky way
This is the best known galaxy.The word galaxy comes from the Greek for milk.Before telescopes were powerful enough to prove that they were made up of individual stars,galaxies look like milky or cloudy areas in the sky .Our solar system is only one of 100-200 billion stars in the Milky way,which is 100,000 light years in diameter.The Sun and all the planets take about 200,000,000 years to complete one orbit around its center.
Brightest- The large Magellanic Cloud which is visible only in the southern hemisphere is 170,000 light years from earth and 39,000 light years in diameter.
Largest- The central galaxy of the Abel 2029 galaxy cluster was discovered in 1990.It is 1070 million light years distant and has a diameter of 5.6 million light years,80 times the diameter of our own galaxy.It has a total light output equivalent to 2 trillion times that of the Sun.
Nearest - Discovered in 1993, the Canis Major Dwarf galaxy is approximately 25,000 light years from the solar systems.
Sources: Whitakers's world of facts
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