Tuesday, August 21, 2012

Super Moon!


 Super moon is a term denotes something extra-than-ordinary moon.
 
When the moon is at it’s nearest in its orbit to earth, super moon happens. This coincides with the full moon.The super moon used to be brighter and larger than ordinary full moon.   During super moon the attraction of moon is slightly more resulting in an increased tidal variation. 

 It is believed that coinciding super moon there would be natural calamities; however, they were not yet proved.

Image courtesy : NASA

Monday, August 20, 2012

Moon Facts


Moon is 1/4 the Size  of Earth
The moon is about 1/4 the size of the Earth.
Only 59% of the moon's surface is visible from earth. From Earth, we always see the same side of the moon; the other side is always hidden. As the moon rotates around the earth, it also rotates around its own axis at the same rate. This is why we always see the same side of the moon.
The Moon is 4.5 billion years old.
Earth From Moon


Moon orbiting counterclockwise from west to east.
The moon orbits Earth at an average speed of 3,683 kilometers per hour.
The Moon travels a distance of 2,290,000 kilometer around the Earth.
The Moon has a diameter of 3,476 kilometers.

The Moon has no atmosphere. There is no wind or weather on the moon.
The Moon is not a light source; it does not make its own light. The moon reflects light from the sun and the Sun always illuminates one side of the Moon.

Earthshine

A few days after new moon, when there is just a very slim crescent, you can sometimes see earthshine on the unilluminated portion of the Moon. Earthshine is caused by sunlight being reflected off the Earth and falling onto the Moon.




Moon Rise

The moon rises in the east and sets in the west.
The new moon rises and sets at approximately the same time as the sun.
The first quarter moon rises at mid-morning and sets at midnight. So it's at its height around dusk, not in the middle of the night.
The full moon rises at sunset and sets at sunrise. The full moon is the only moon that will be overhead in the middle of the night.
The last quarter moon rises at midnight and sets at mid-morning. So unless you're a late-owl, you would never even see this moon.

Sunday, August 5, 2012

Moon Ring





On any full moon day one can see a bright ring around the moon if the sky is clear.  This is not an actual ring around the moon rather it is an illusion or a halo effect.  

In the upper atmosphere, in the absence of sunlight, the temperature would be much low to the extent water vapour in that layer could easily form tiny  ice crystals or a layer of thin cloud.  
 When the bright light from the moon pass through this thin cloud with an inclination of 22 degrees, the ice crystals in the thin filmy cloud diffract the light resulting in a halo like appearance.  As a result in addition to the direct moonlight, one could also see diffracted moonlight in a circle 22 degrees away from the moon. This is popularly known as ‘moon ring’.

It is a belief that bigger halo is an indication of an imminent storm or a rain.  Sometimes people used to count the number of stars inside the moon ring to predict the number of days of the approaching storm or rain.