astronomy

What is Eclipse?



Eclipse is a major term in Astronomy and it is defined as the partial or complete masking of one celestial body over another. Scientifically, eclipse use to occur when 3 celestial objects gets aligned in a row. This is a temporary masking where either one body goes into shadowed area created by another or in another case a celestial body use to pass between viewer and the object under consideration.

If we talk as per the prospective of a human being on earth then Sun is known to be eclipsed whenever moon finds its path between earth and sun. On the other side, eclipse of moon occurs when earth moves between the moon and the sun. In this case sunlight is not able to reach up to surface of moon, ultimately it goes dark.

Eclipse for natural satellites or spacecraft that is flying near a planet occurs when it moves into the shadow of that planet. There are so many scientific terms associated with this astronomical process. Note that when recognizable size of eclipsed or masked body is smaller as compared to the body that is masking it then this process is termed as Occultation. One common example of such process is disappearance of nebula, star or some planet in the shadow of moon. The process of fading a spacecraft or natural satellite behind a large body in the solar system is another example of occultation.

Another important term is Transit. It uses to occur when a small body in the space passes over the area of larger body. In the most common case, Venus and Mercury use to pass over Sun or any other larger planet and the phenomenon that is known as Transit use to occur.

Considering any two bodies in the space, it is possible to draw a straight line that starts from one object to another. Here the second object in the row will block a specific amount of light that is transmitted by first one. This process creates a shadowed region around line axis. Actually, these objects are simply moving around each other and hence the shadowed part is going to glide through particular region in the space and it will stay in that location for a predefined time period as per the speed of two bodies. This process is well known as eclipse.

Studies reveal that most of the objects in space that are involved in eclipse process are usually of round shape. Scientists define three different terminologies for shadowed region of the object under consideration during eclipse process:

1. The first term is Umbra, in this case, object use to cover light source completely. If we consider sun then the mentioned light source will be photosphere.

2. Second important term is Antumbra, where object use to be too small that when it stands in front of light source it is not able to cover it completely.

3. The third one is Penumbra, which defines partial presence of object in front of considered light source.