ഗ്രഹണം പതിവുചോദ്യങ്ങൾ

How does a solar eclipse occur?

 The Moon, a satellite of the Earth, may come directly in front of the Sun as it orbits the Earth.  At that time the moon may partially or completely cover the sun.  This is solar eclipse.  In other words, a solar eclipse occurs when the moon's shadow falls on the earth.  Because the Moon is smaller than the Earth, the Moon's shadow will only partially cover the Earth.  So solar eclipse will be experienced only in those parts of the world.  In those places, the light of the sun will be less at that time.

What is a total solar eclipse?

 A total solar eclipse is when the moon completely covers the sun.  If you imagine a line from the center of the sun through the center of the moon, a total solar eclipse will be experienced only where it lies close to where it passes through the earth.  Even under the most favorable conditions, it can be seen for less than 6-7 minutes at most.  Even within 270 km radius, there has not been a total eclipse in Kerala in recent times.

What is an annular solar eclipse?

 An annular eclipse is when the moon covers all but the edge of the sun's image.  It is called an eclipse because the Sun will appear in a circle at that time.

 The angle that the Sun and the Moon make in the sky is about half a degree.  More precisely it can be 0.488 degree to 0.568 degree in case of Moon.  The reason for this difference is that the distance between the moon increases and decreases as it moves around the earth.  In case of Sun it can be 0.527 degree to 0.545 degree.  This difference is due to the difference in distance between the sun and the earth.  Because of these differences, in some cases of eclipses, the lunar image will be smaller than the solar image.  Then the solar image will not be completely covered.  A circle may remain.  See that as an annular eclipse.  In December 2019, there will be an annular eclipse in North Kerala.  Elsewhere in Kerala it will be a partial eclipse

What is a partial eclipse?

 A partial solar eclipse is when the sun is partially covered by the moon.  If only the weakest part of the shadow cast by the moon – i.e. the penumbra – falls, it is a partial eclipse.  A partial eclipse will occur over a relatively large area around the areas where the total eclipse occurs.

What is a hybrid solar eclipse?

 A hybrid solar eclipse is a phenomenon in which a solar eclipse occurs in some places as a total eclipse and in other places as an annular eclipse.  This is caused by the difference in the distance between the moon and the place where its shadow falls on the earth within a few hours of the eclipse.  This happens when the earth passes through the junction of umbra and antumbra.  This is so unlikely that it only happens at a rate of about once a decade.  No such eclipse will happen in our country in near future.

How long does a solar eclipse last?

 A partial eclipse can last for hours.  But the circular eclipse or the total eclipse lasts only 6 or 7 minutes at most.  The eclipse on December 26 will last for a maximum of 3 minutes and 40 seconds.

Why do not all black vavs have eclipses?

 The black moon or new moon is when the moon comes between the sun and the earth.  At that time, one half of the Moon will be towards the Earth and the other half will be towards the Sun.  Then there will be light in the half towards the sun.  The other half facing us will be dark because no sunlight falls on it.  We cannot see the moon because it does not produce its own light.  Every time the moon orbits the earth, there is a new moon.  This can happen twelve or thirteen times a year.

 Now let's see how solar eclipse happens.  If the Moon passes directly in front of the Sun during Amavasi days, a part of the Sun will appear to be obscured by the Moon as seen from Earth.  This is solar eclipse.  This may not happen on every new moon day.  Sometimes the moon image will pass along the north side of the sun image.  Sometimes it passes along the south side.  Sometimes the sun's image is partially or completely obscured for a while when it passes straight ahead.  That is solar eclipse.  There is a slight tilt of 5 degrees between the plane of the Moon orbiting the Earth and the plane of the Earth orbiting the Sun.  That is why solar eclipses happen only on new moon days.

 It is for this reason that there is no lunar eclipse on all the full moon days (white moon).

https://luca.co.in/eclipse-faq/