- Composition of earth: (Oxygen 46.5%, Silicon 27.72 %, Aluminum 8.13%, Iron 5.01%, Calcium 3.63%, Sodium 2.85%, Potassium 2.62% and Magnesium 2.09%).
- Light year is the distance travelled by light in ‘One year’.
- A light year, as a unit of measurement of distances of heavenly, is equal to 46 trillion kilometers.
- Stars which appears single to the naked eye but are double stars when observed by a telescope, are known as ‘Bindaries’.
- A star which appears ‘Blue’ is hotter than the sun.
- Light takes nearly 4 years to reach us from the nearest star.
- The energy generation in stars is mainly due to the fusion of light nuclei.
- The change in color of stars arises due to ‘Variation in their surface temperature’.
- The altitudes of heavenly bodies appear to be greater than they actually are (this is due to ‘Atmospheric refraction’.
- Twelve constellations referred to as “Zodiac” are imaginary region that encompass the path of the planets.