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Solar eclipse and lunar eclipse are types of eclipses which occur naturally in the universe. This phenomenon is dependent on the position of the alignment of the celestial bodies in a straight line. We know that the earth revolves around the sun at the same time of the moon rotating around the earth. When all three of them coincide in a straight line such that it is partially hidden to the observer, an eclipse takes place.
Let us study in detail about an eclipse, its types, and the differences between solar eclipse and lunar eclipse.
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What is an Eclipse?
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Eclipse refers to an astronomical event which occurs when a celestial body is hidden for sometime by moving into the shadow of another body. It also happens if another body comes in between itself and those who see or observe it. When three or more celestial bodies are aligned in one straight line, the term is coined as ‘syzygy’.
The term has been derived from the Greek word “ekleipsis”, which means the downfall or darkening of a heavenly body. It basically implies the dark phase or the phase of the body where it ceases to exist any longer.
Eclipses are separated by certain intervals of time. This time period is known as an eclipse season. Solar eclipses can occur two to four times a year, however a total solar eclipse may be decades apart from the next one. The frequency of lunar eclipses per year is two.
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What is a Solar eclipse?
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Solar eclipse takes place when celestial bodies like the moon for instance, come in between the sun and earth. In the course of this event, the distance of the moon from the earth acts as the deciding factor of the type of eclipse to occur. This means it decides whether it will be a partial or a total eclipse.
A total eclipse is said to occur when the viewer views the eclipse by staying within the umbra portion of the shadow. In simple words, in total eclipse, earth intersects the umbra portion of the moon’s shadow. A partial eclipse occurs when the viewer or the observer stands inside the penumbra region. When the umbra is not in contact with the surface of earth or the observer is within the antumbra, we call it an annular eclipse. In this case the sun remains partially hidden.
The lifespan of a solar eclipse is very brief and lasts for about 7 minutes 31 seconds. Studies have proven that looking at a solar eclipse for a longer time with a naked eye can damage the cells of the retina. This is also called eclipse blindness. People often do this to identify the diamond ring effect around the eclipse. However it has been advised to use glasses when viewing a solar eclipse.
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What is a Lunar Eclipse?
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Lunar eclipse occurs when the earth is between the sun and moon. During the occurrence of a full moon, the moon moves through the shadow of the earth. A lunar eclipse may be observed from an entire hemisphere in contrast to the solar eclipse. The nature of a lunar eclipse varies according to different situations.
A penumbral lunar eclipse occurs when the moon moves past the earth’s penumbral region. A partial lunar eclipse occurs when the moon happens to partially cross the earth’s region of umbra. When the moon moves entirely into the earth’s umbra, it is called a total eclipse. The duration of a lunar eclipse is for about an hour or so. It is because of this reason that these eclipses can be observed from any given location. It takes several hours to complete and ranges from 30 minutes to an hour. It occurs in three phases.
Blood moon is a common phenomenon when the moon appears to be faintly red in colour. The light which is refracted from the surface of the earth, scatters all the blue light most. The remaining light scattered by the atmosphere has shorter wavelengths so the moon appears to be red in colour.
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Difference between the Solar Eclipse And Lunar Eclipse
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Mentioned below are some important points of differences between a solar eclipse and a lunar eclipse. These are as follows,
| Solar eclipse | Lunar eclipse |
|---|---|
| Solar eclipse is an eclipse where the moon is in between the sun and earth, all three of them being aligned in a straight line. | Lunar eclipse is an eclipse where the earth comes in between the sun and the moon, all three of them being aligned in a straight line. |
| The time for which a solar eclipse lasts is very less as compared to a lunar eclipse. It is 7 minutes 31 seconds. | A lunar eclipse considerably lasts much longer than a solar eclipse, and measures about almost an hour. |
| A solar eclipse takes place during day time and can be seen only by limited areas. | A lunar eclipse occurs during night-time and can be observed by many places. |
| A solar eclipse is likely to occur only once in 18 months. | Lunar eclipses are known to occur twice in a single year. |
| It has been advised that a solar eclipse should not be seen with a naked eye as it affects the eyes to a great extent. | A lunar eclipse can be observed with naked eyes. It does not cause harm to the eyes in any way. |
| Solar eclipse occurs during the new moon phase. | Lunar eclipse takes place during the full phase of the moon. |
Things to Remember
- An eclipse has been defined as an astronomical event naturally occurring in the universe when a celestial body is partially hidden temporarily because of passing onto the shadow of another body. In an eclipse the sun, moon, and earth are aligned in a straight line.
- Depending upon the alignment of the planets, there are two main eclipses, named as solar eclipse and lunar eclipse. A solar eclipse occurs when the moon comes in between the earth and sun. The moon completely blocks the light of the sun and is either partial or total.
- Studies have shown that a solar eclipse is not to be observed with the naked eye as it can affect the eyes extensively. Glasses should be used to view a solar eclipse else it may lead to damaging the retinal cells and permanent loss of sight.
- Lunar eclipses occur when the earth comes in between the sun and moon. The shadow of the earth covers the moon. Lunar eclipses occur in three different types. These are the partial, total, and penumbral eclipses.
- A solar eclipse is of an opposite nature as compared to the lunar eclipse. Solar eclipses can be viewed from a limited place only whereas people may observe a lunar eclipse everywhere. Solar eclipses last very less than a lunar eclipse.
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Sample Questions
Ques. What is an eclipse? (2 marks)
Ans. An eclipse is referred to as an astronomical event which happens because of a heavenly body being partially concealed due to moving into the shadow of another celestial body. In an eclipse, all three bodies are in a straight alignment. For example the viewer may see no moon in a lunar eclipse as the earth stands between the moon and the sun.
Ques. How is the lunar eclipse different from solar eclipse? (2 marks)
Ans. The biggest point of difference is, in a lunar eclipse the earth comes between the moon and the sun. On the contrary, in a solar eclipse, the moon is in between the sun and earth. A lunar eclipse lasts for about an hour which is much more than 7 minutes 31 seconds, the time for a solar eclipse. It is observed during night time whereas a solar eclipse takes place during the day. People may observe a lunar eclipse two times in one year whereas a solar eclipse occurs only one time within 18 months.
Ques. Define solar eclipse. (2 marks)
Ans. The eclipse of the sun is known as the solar eclipse. When the moon stands in between the earth and the sun, this eclipse takes place. Three types of eclipse named as the total eclipse, partial eclipse, and annular eclipse can occur depending upon the distance of the moon from the earth. The event of a solar eclipse generally lasts for about 7 minutes 31 seconds.
Ques. Why does the moon appear red sometimes? (2 marks)
Ans. This phenomenon takes place during a lunar eclipse. The moon crosses the outer penumbra and the inner umbra region of the earth. The region of the outer penumbra is devoid of any light source and is therefore dim. Whereas in the inner umbra portion, faint light refracted by the earth’s atmosphere falls upon the moon and makes it shine. The particles in this light scatter the blue light. This leaves a reddish colour and therefore the moon appears to be red. This is popularly known as the blood moon.
Ques. Why should we not see a solar eclipse with naked eye? (2 marks)
Ans. Research has found that a solar eclipse should not be viewed with the naked eye as it can cause hazardous effects on the organ. Facing the sun directly at this time may cause eclipse blindness or burning sensations in the retina. It can also damage the cells present in the eye and ultimately lead to complete blindness. It is hence advised to use glasses while looking at the sun during a solar eclipse.
Ques. Define phases of shadow in an eclipse. (2 marks)
Ans. The shadow of an object during an eclipse is divided into three main regions. These are as follows,
- Umbra - This is the region inside which the celestial body entirely covers the light source causing a complete shadow.
- Antumbra - This region begins at the vertex of the umbral region. Inside this region, the body is face to face with the light source but cannot cover it entirely. It covers it partially.
- Penumbra - Inside this region, the celestial body partially faces the light source.
Ques. What are astronomical bodies? (2 marks)
Ans. Astronomical objects, also known as celestial bodies, are naturally occurring entities in the universe. It should be remembered that astronomical bodies are different from astronomical objects. Astronomical bodies are singular entities like planets in our solar systems, stars, moons. On the other hand, astronomical objects are in the form of multiple bodies like galaxies, clusters of stars, etc.
Ques. Why does an eclipse happen? (2 marks)
Ans. When the moon starts moving around the orbit of earth and moves between the sun and earth, an eclipse takes place. During this phenomenon, the moon prevents the light of the sun from reaching the earth. Hence, the earth is left without any light source. This causes a solar eclipse. As the moon casts a shadow on earth, an eclipse occurs.
Ques. How is a lunar eclipse observed by many places but a solar eclipse is not? (2 marks)
Ans. The reason behind this is that both of the eclipses have an equal frequency. Lunar eclipses are more visible than solar eclipses because a major part of the light source is blocked and the earth casts a much larger shadow on the moon. Whereas, in a solar eclipse the shadow casted by the moon on earth is comparatively smaller because of the moon being smaller in size. This increases the probability of you seeing a lunar eclipse more than a solar eclipse.
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