What is a Solar Eclipse? Detailed Information on Solar Eclipse Types
The last solar eclipse was seen on December 26, 2019. Fully visible from Saudi Arabia, India, Sumatra, and Borneo, the eclipse was partially visible from Australia and much of Asia.
Solar eclipse, which can only occur at the time of the new Moon, occurs when the shadow of the Moon falls on the Earth by passing between the Sun and the Earth. However, what kind of solar eclipse will occur from the alignment of the Sun, Moon, and Earth depends on different factors. You can see what these varieties are and more in the rest of the article.
The occurrence of an eclipse depends entirely on coincidences in time and celestial mechanics. The Moon, which is about 4.5 billion years old, is gradually moving away from the Earth every year (approximately 4cm annually). At the moment, the distance of the Moon to our Earth makes it appear the same size as the Sun and for this reason, solar eclipses are commonplace; but this is not always the case.
Types of Solar Eclipse
There are four different solar eclipse types: complete, annular, segmented, and hybrid. Let’s take a look at how it came into being:
Total Solar Eclipses
These are the sweet accidents of nature. The Sun with a diameter of 1,392,700 km is 400 times the Moon with a diameter of 3,474.2 km. But at the same time, the distance between us and the Moon is 400 times shorter than it is with the Sun (this ratio can vary since the orbits are oval). Due to these situations, when the two orbits align, the new Moon can hide the Sun exactly behind it. A solar eclipse is seen anywhere in the world approximately every 18 months.
There are two types of shadow: the full shadow (umbra), the part that blocks all of the sun’s rays, completely dark, and the part that appears as a cone. The penumbra surrounds it. Half-shadows are the lighter, funnel-shaped parts where the sun’s rays are less blocked.
During a total solar eclipse, the full shadow of the Moon falls on the Earth, and this shadow can roam 1/3 of the Earth in a few hours. Those lucky enough to live in places where this full shadow passes can see how the Sun slowly transforms into a crescent shape and how the shadow of the Moon falls on them.
When the Sun is exactly behind the Moon, the thin outer atmosphere of the Sun, which is called the corona, becomes visible. This spectacular event can last up to 7 minutes and 31 seconds, but generally full solar eclipses are much shorter than that.
Partial Solar Eclipses
Partial Solar Eclipses occur when only the semi-shadow of the Moon (penumbra) falls on you. In these cases, how much can be seen depends on various factors, and part of the Sun always remains visible.
Usually, penumbra casts a faint shadow on our planet over the polar regions; In these cases, those who are far from the poles but still under the half-shadow cannot see more than a tiny part of the Sun behind the Moon. In a different case, those within a few thousand kilometers of areas of the total eclipse may witness a total eclipse.
The closer you get to the area of the total eclipse, the darker the shadow gets. For example, if you are just outside the region of the total eclipse, you will see the Sun slowly transforming into a thin crescent moon and thickening again as the shadow passes.
Annular Solar Eclipses
Rare annular Solar Eclipses are similar to Total Solar Eclipses but are also completely different. The sky darkens completely… somehow; Most of the sun is visible and a strange “false twilight” occurs. Ringed eclipses are, contrary to what is thought, a variation of fragments rather than complete ones. The maximum duration of annular eclipses is 12 minutes 30 seconds.
However, annular solar eclipses are the same as total eclipses in that the Moon passes through the Sun exactly in the middle; the difference is, in these eclipses, the Moon appears so small that it cannot hide the Sun fully behind it. This event is caused by the Moon’s oval orbit. The distance of the moon to the Earth as it rotates around varies between 363.104km and 405.696km. But the full shadow of the Moon cannot exceed 379,322 km.
In other words, if the Moon is farther away, the tip of the shadow cannot reach the Earth. In such an eclipse, a theoretical continuation of the full shadow called antumbra reaches the earth, and when those in this region look up, they see a ring around the Moon, in other words, a “circle of fire”. Putting a fifty penny on a lira could be a correct example of this eclipse.
Hybrid Solar Eclipses
This type of eclipse occurs as a result of finding the full shadow of the Moon at the border distance from which it can reach the Earth. Often, these eclipses begin as an annular eclipse due to the inability of full shadow to reach the earth. As it moves in orbit, it returns to full eclipse due to the circular shape of the Earth, and then to a cyclic eclipse again.
Total, cyclic and hybrid eclipses are also called “central” eclipses, as the Moon takes the Sun exactly behind it, unlike partial eclipses. Of all eclipses, 28 percent are complete, 35 are partial, 32 are cyclic and only 5 are hybrid.
Prediction of Solar Eclipses
Of course, there is not an eclipse on every new Moon. The orbit of the Moon is curved 5 degrees from Earth’s orbit to the Sun. For this reason, the shadow of the Moon usually falls either above or below the Earth and there is no eclipse.
As a rule, a New Moon is aligned directly in front of the Sun at least 2 times a year (this number can vary up to 5 per year). This point of alignment is called a node. How close a new Moon passes to a node determines whether the eclipse will be partial or central. The distance between the Moon and the Earth and at least as important as the Earth’s distance from the Sun determines whether the eclipse will be complete, cyclic, or hybrid.
However, these alignments that cause eclipses are not accidental. After a certain time interval, an eclipse repeats itself. This time interval, called the Saros cycle, has been known to astronomers since 2800 years ago. The word Saros means “cycle” and equates to 18 years 11⅓ days.
After this time interval passes, the Sun and Moon get closer to a knot almost as much as in the previous eclipse. Of a day within this range causes the next eclipse to be seen west of the circumference of the Earth from where the previous eclipse occurred.
For example, on March 29, 2006, a total eclipse that had advanced from the west and north Africa to south Asia will occur again after a Saros, that is, on April 8, 2024. But this time, it will not move from Africa to Asia, but from northern Mexico to the maritime provinces of central, eastern America and Canada.
Solar Eclipse Safety
When a solar eclipse approaches, warnings, and advertisements in the media such as “You should not look at the Sun with your naked eye, otherwise you may go blind” start to spin. This situation gives many people the idea that solar eclipses are dangerous.
This is not the case! The sun itself is always dangerous! The sun emits infrared rays that can harm our eyes. Normally, we don’t have a reason to gaze at the Sun anyway, but who wouldn’t want to watch a solar eclipse, even though we shouldn’t?
Still, there are safe ways to do this… The safest way to monitor an eclipse is to make a “pinhole camera”. The pinhole or small hole is used to project the Sun’s image on the screen about 1 meter behind the hole. A binocular or a small telescope can also work by projecting a magnified image of the Sun onto a white card.
The farther you move the card away, the clearer the image becomes. However, you can also look for sunspots. You will see that the sun darkens as it approaches its edges. This method is safe as long as you are not looking directly at the Sun through binoculars or telescopes. In simpler words; never look at the Sun with its blinding bright surface visible.
Another variation of the pinhole contact is the “pinhole mirror”. Cover a pocket mirror with paper with a 6.5-millimeter hole in the center. Open a window that sees the sun and place the mirror to receive the sun’s rays. Once you’ve made the correct placement, you will see a disc of light reflected from the mirror on a wall in the room.
This disk is a reflection of the Sun, and the image grows as you move the mirror away from the wall (about 3 centimeters per 3 meters). Play dough will do the trick to keep the mirror in place. Try paper with different-sized holes. You will notice that when the hole is large, the image is bright but messier. Conversely, as the hole gets smaller, the image gets sharper but pale.
First of all, make sure the optical quality of the mirror is good enough to create a nice and clear reflection. Make the room as dark as you can, and of course, don’t let anyone look directly at the Sun’s reflection in the mirror.
If you’re amongst leafy trees during a partial eclipse, take a look at their shadows.
What do you see? Is it worth taking a picture? The spaces between the leaves act as pinholes and reflect the partially eclipsed Sun to the ground. This event occurs as a result of the diffraction of the rays, which are a property of light. According to Vince Huegele, an optical physicist at the Nasa Marshall Space Flight Center, light rays do not pass directly through the gaps or pinholes between the leaves; instead, it bends at the corners. This wave effect also creates a kind of circle pattern.
Acceptable filters used for unaided detention observations contain aluminum coated polyester. Some astronomy dealers sell this type of polyester filter designed solely for observing solar eclipses. However, 14 arc welder glasses can also work for you and you can find them in many places for low prices. Whatever method you will use, never forget to test it before the eclipse day.
Sunglasses, old color negative films, silver-free black and white films, neutral density filters, and polarizing filters are among the unacceptable filters. Although these materials have very low levels of light transmission, they transmit unacceptably high levels of near-infrared radiation, which can lead to thermal retinal burns. If you see the sun paler or do not feel discomfort while looking, it does not mean that your eyes are safe.
There is only one safe moment when you can look directly at the Sun: the moment during a total eclipse when the Sun is completely hidden behind the Moon. In these precious seconds or minutes, the glamorous corona envelops the sun darkened in all its glory, shimmers, and emits wonderful pearly white lights. The hue of the glow to the eclipse and the size of the pattern may vary; but it is always eye-catching and delicate, with a sheen that resembles pure daybreak.
This beautiful image can come up in a few different ways. Sometimes it always looks plain; other times it fires long rays in three or four directions. Although this beautiful image is safe, it is better not to get distracted; Because after a while the Sun starts to appear again, the corona becomes invisible and you need to protect your eyes again.
Solar Eclipses in Ancient Times
As far as we can detect, the first recorded solar eclipse occurred 4000 years ago. In ancient China, it was thought that the slow darkening of the Sun was caused by a dragon trying to eat it. And the task of the court astronomers was to scare away the dragon by shooting arrows, playing drums, and all the ugly sounds they could make.
In an ancient Chinese classic, Shujing (or History Classic), two court astronomers Hsi and Ho get drunk, unaware that an eclipse will occur that day. In the aftermath of this, the 4th Emperor of the Xia Dynasty, Zhong Kang, takes the heads of Hsi and Ho and punishes them. The eclipse in this event, BC. It happened on October 22, 2134.
In the Bible Amos 8:9, the words are: “I will set the sun in the daytime, and I will darken the Earth by the day. As it was written on an Assyrian tablet, biblical scholars said these words were written in BC. He thinks it is a tribute to the famous solar eclipse that was observed on June 15, 763.
A solar eclipse once even stopped a war. According to the historian Herodotus, there was once a 5-year war between Lydia and the Median Empire. Before the war enters its 6th year, the Greek scholar Thales of Miletus informs the Ionians that the day will turn into night. B.C. On May 17, 603, the Sun turns dark, just as Thales said. Believing that this is a sign from above, warriors declare a ceasefire.
On May 5, 840, Charlemagne’s son, the cowardly Emperor Louis of Bavaria, gave a new meaning to the phrase “to be scared”. The emperor witnesses a solar eclipse that lasts longer than usual. In the eclipse, which lasted about five minutes, the Emperor was so afraid that he died of fear as soon as the eclipse was over!
Contemporary Studies on Solar Eclipse
Astronomers have learned a lot by studying eclipses. Even in the 18th century, observation of solar eclipses was described by astronomers as abandoned hoards; but it was not always easy to obtain this information.
Samuel Williams, a professor at Harvard, travels to America to Penobscot Bay to observe a total solar eclipse on October 27, 1780. But he suddenly finds himself in the middle of the American War of Independence. Fortunately, the British military provides a confident transition to the surveillance team, citing science as a priority over politics.
Still, this is nothing more. But this time too, Williams makes a critical mistake in his calculations and positions his team in Islesboro – just outside the area where the total eclipse can be observed. I guess it is very sad to see the ever-narrowing crescent start to thicken again after sliding under the darkness of the Moon and crossing the other side!
During an eclipse, several ruby-red dots can be seen circling the dark Moon. These are jumps of the Sun and they gush out from the surface of the Sun as hydrogen, which has become glow from the heat. During the total eclipse on August 18, 1868, French astronomer Pierre Janssen studied these jets with his spectroscope and discovered a new chemical element. Later, two British astronomers J. Norman Lockyer and Edward Frankland named this element “helium” after the Greek word helios, meaning “sun”. This gas element was not identified until 1895.
During a total eclipse, some bright stars and planets in the dark sky can be better observed by completely blocking the sun’s rays. In such cases, astronomers can test Einstein’s theory of relativity, which has now been proven.
The theory of relativity suggested that rays from stars beyond the Sun were bent when passing near the Sun rather than radiating straight. When astronomers compared the stars in photographs taken during the total solar eclipse of May 29, 1919, with the stars in a photograph taken at night, they obtained results that strongly supported Einstein’s theory.
Now, thanks to our advanced technology, we don’t need to wait for an eclipse to observe and investigate things like ancient astronomers; however, a total solar eclipse will always remain among the most beautiful natural images on Earth. Be sure to include witnessing one of these on your to-do list before you die; You will not regret it.