Hi. Welcome back.
Watch the abhishekam to Raghu in following link:
https://www.youtube.com/watch?v=D6KFMa1NF4E
If there is one thing most dreaded by the Hindus, it is the Rahu Kalam. The entire Hindu world shuns almost all deeds during this period of 90 minutes every day. There are people mounting criticism on this, as they feel it wastes millions of hours everyday. This blog is to explore this daily occurrence to understand why the ancient Hindus considered this period to be inauspicious. Is there a Vedic background for this and is there any scientific explanation possible ? Were the ancients fools to accept such theories or have we not understood this properly ? Is there any hidden message from the stars above for humanity to safeguard themselves from certain invisible celestial events? Let me add to your knowledge on what I have gathered on these aspects.
India was in the forefront of astronomy with Vedic mathematics and astrology. We can rightly boast of accurately calculating the planetary movements, be it the distance of planets, prediction of eclipses, shifting of planets from one rasi to another and so on. Even without the assistance of telescopic interventions, our ancients were able to tell us about the planetary movements to a great degree of accuracy. Works of Indian astronomers such as Aryabhatta speaks volumes on this. Vedic astrology as well was supported by these theories, which have proved 100% accurate today on locating the planets around the 360 degree orbit of the Sun.
Vedic periods visualised the personification of these planets and claimed they descended on earth as various gods and goddesses for the welfare of humanity. One interesting aspect of this is the personification of invisible planets of Raghu and Kethu. The ancients knew very well that there are no such planets that could be seen by us and were very categorical of their existence as "Chaya Graha", the shadow planets. How did they manage to fabricate this concept, which today has been proved correct in predicting the eclipses, one wonders. They had the knowledge of north and south nodes, which are the intersecting points of the planes of sun and moon's movement and named the ascending node as Raghu and descending node as Kethu. They could also map the apparent movement of the Sun around the Earth as well as the angular movement of moon around the sun, accurately to a high degree of precision.
Rahu in Indian Astronomy
Rahu is one of the 9 astronomical bodies or the navagrahas, which are believed to influence lives of humans on earth. Rahu is the north lunar node or a shadow entity, and not a real planet. Rahu is believed to have powers to influence life of humans. Apart from the influence Rahu has on an individual's birth chart, it is also considered to influence certain times of the day - this period of time is called Rahu Kaal. Starting anything new is avoided during this time since it is considered inauspicious period.
In Vedic astrology, the seven planets, Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn, are allotted a whole day of the week. Again, every planet in every day has its ruling time. During the particular time slot, a planet rules at a particular time. It is otherwise called a 'Hora Time'. However, the nodal planets (Rahu and Ketu) have no such allocation of a whole day in a week. However, they have been associated with the power to rule for one and a half hours every day of the week, which is known as Rahu Kalam and Yamagandam. As the seven planets have been allocated for weekdays, Rahu & Ketu and other upagraha were allowed to rule the stipulated time duration on all days. The 1/8th part of the day time is allocated for these planets and upagrahas. The transition of Rahu node between Sunrise and Sunset determines the Rahu Kaal.
In simple terms, it is the point of intersection of the paths of Sun and Moon as they move in the sky. In the image above, the ascending node is Rahu and the descending node is Ketu. Since eclipses of the Sun and Moon can happen only at these points, Rahu and Ketu are associated with Sun & Moon and believed to cause eclipses.
Have a look at the following link to understand it much better:
https://www.youtube.com/watch?v=pcbdUJGYxtM
Rahu Kaalam is considered inauspicious period in Indian astrology, due to its association with malefic, Rahu. During Rahu Kaal, it is believed that Rahu ‘envelops’ or ‘covers’ the mind, causing it to ‘go blind’, and so, the mind doesn't think clearly. Hence, Rahu Kaal is considered inauspicious. The segments are calculated by taking the total 12 hours of time between sunrise ( 6 a.m.) and sunset ( 6 p.m.), at a given place, and then dividing this time duration by 8. Astronomically, in the Hindu Panchangam, the ever varying planetary configurations mean that the auspicious hours during each day will not always fall at the same moment of time. Rahu Kaalam, Gulikai, Yama Gandam are the time periods which are especially considered inauspicious or unlucky.
Likewise, Yamagandam refers to the time of Yama, the son of Planet Sun (the Lord who is responsible for carrying the Soul (Atma) to its deserving place upon the death of a person). Gulikai Kalam also occurs for a duration of approximately one and a half hours each day. Gukilai Kalam is the hour of Gulikan, the son of Saturn (Shani). This is the time ruled by Saturn and should be avoided as it is generally considered inauspicious. It is believed that any activity done in Gulikai Kalam repeats itself. So, it is essential to avoid rituals like death-related rites during this period, as we do not want it to get repeated.
Why Rahu and Ketu are called Chaya graha (shadow planets)? Please see the following link:
https://www.youtube.com/watch?v=mPk23GA3Q8c
So much for the significance of Raghu Kaalam. Now let us see how a particular time is allotted in a day to Rahu and its explanation thereof. Following table briefs the timings:
 |
| The mnemonic is: Mother Saw Father Wearing The Turban Slowly. |
For example on Sunday first segment
· 6:00 to 7:30 - Red
· 7:30 to 9:00 - Orange
· 9:00 to 10:30 - Yellow
· 10:30 to 12:00 - Green
· 12:00 to 13:30 - Blue
· 13:30 to 15:00 - Indigo
· 15:00 to 16:30 - Violet
· 16:30 to 18:00 - Ultra Violet which is Rahukalam
Likewise, start assigning the traditional Indian mythological colours Orange on Tuesday, Yellow on Thursday, Green colour on Wednesday, (Silver) Blue colour with Friday, Indigo colour on Saturday and finally Violet on Monday. You will see the Ultra Violet colour appears on the Rahu Kaal time of the respective days. You will observe here that we use exactly the same colours in temples and during Navagraha pooja for worshiping the planetary gods.
On Monday, first segment will be Violet
6:00 to 7:30 - Violet
· 7:30 to 9:00 - Ultra Violet which is Rahukalam
· 9:00 to 10:30 - Red
· 10:30 to 12:00 -Orange
· 12:00 to 13:30 -Yellow
· 13:30 to 15:00 - Green
· 15:00 to 16:30 - Blue
16:30 to 18:00 - Indigo
On Tuesday, first segment will be Orange
6:00 to 7:30 - Orange
· 7:30 to 9:00 - Yellow
· 9:00 to 10:30 - Green
· 10:30 to 12:00 -Blue
· 12:00 to 13:30 -Indigo
· 13:30 to 15:00 - Violet
· 15:00 to 16:30 - Ultra Violet which is Rahukalam
· 16:30 to 18:00 - Red
By now, it is clear from the above that traditional astrology calculated that this part of the day as malafic in nature as it has additional UV radiation entering the earth and therefore prevented us from venturing outside, especially on travel, and to remain in-house to safeguard us from the ill effects of exposure to UV radiation. It is certain that the UV radiation would be maximum at noon time, when the Sun is directly over your heads and the UV rays have lesser travel distance to reach the grounds. Accordingly, the mid-week Bhudan (Wednesday) has its Rahu Kaalam starting at 12 noon.
More about Ultra Violet Radiation:
Radiation is the emission (sending out) of energy from any source. There are many types of radiation, ranging from very high-energy (high-frequency) radiation – like x-rays and gamma rays – to very low-energy (low-frequency) radiation – like radio waves. UV rays are in the middle of this spectrum. They have more energy than visible light, but not as much as x-rays.
There are also different types of UV rays, based on how much energy they have. Higher-energy UV rays are a form of ionizing radiation. This means they have enough energy to remove an electron from (ionize) an atom or molecule. Ionizing radiation can damage the DNA (genes) in cells, which in turn may lead to cancer. But even the highest-energy UV rays don’t have enough energy to penetrate deeply into the body, so their main effect is on the skin.
Such radiation is all around us, though we can only see some of it and is made up of minute packets of energy or 'particles,' called photons, which travel in a wave-like pattern and move at the speed of light. The Electro Magnetic spectrum is divided into categories defined by a range of numbers. These ranges describe the activity level, or how energetic the photons are, and the size of the wavelength in each category.
For example, at the bottom of the spectrum radio waves have photons with low energies, so their wavelengths are long with peaks that are far apart. The photons of microwaves have higher energies, followed by infrared waves, visible light, Ultra Violet rays, and X-rays. At the top of the spectrum, gamma rays have photons with very high energies and short wavelengths with peaks that are close together.
UV radiation is divided into 3 main groups:
UVA rays have the least energy among UV rays. These rays can cause skin cells to age and can cause some indirect damage to cells’ DNA. UVA rays are mainly linked to long-term skin damage such as wrinkles, but they are also thought to play a role in some skin cancers.
UVB rays have slightly more energy than UVA rays. They can damage the DNA in skin cells directly, and are the main rays that cause sunburns. They are also thought to cause most skin cancers.
UVC rays have more energy than the other types of UV rays. Fortunately, because of this, they react with ozone high in our atmosphere and don’t reach the ground, so they are not normally a risk factor for skin cancer. But UVC rays can also come from some man-made sources, such as arc welding torches, mercury lamps, and UV sanitizing bulbs used to kill bacteria and other germs (such as in water, air, food, or on surfaces).
Sunlight is the main source of UV radiation, even though UV rays make up only a small portion of the sun’s rays. Different types of UV rays reach the ground in different amounts. About 95% of the UV rays from the sun that reach the ground are UVA rays, with the remaining 5% being UVB rays.
The strength of the UV rays reaching the ground depends on a number of factors, such as:
Time of day: UV rays are strongest between 10 am and 4 pm.
Season of the year: UV rays are stronger during spring and summer months. This is less of a factor near the equator.
Distance from the equator (latitude): UV exposure goes down as you get farther from the equator.
Altitude: More UV rays reach the ground at higher elevations.
Clouds: The effect of clouds can vary, but what’s important to know is that UV rays can get through to the ground, even on a cloudy day.
Reflection off surfaces: UV rays can bounce off surfaces like water, sand, snow, pavement, or even grass, leading to an increase in UV exposure.
Contents of the air: Ozone in the upper atmosphere, for example, filters out some UV radiation.
The amount of UV exposure a person gets depends on the strength of the rays, the length of time the skin is exposed, and whether the skin is protected with clothing or sunscreen.
People can also be exposed to man-made sources of UV rays. These include:
Sunlamps and sunbeds (tanning beds and booths): The amount and type of UV radiation someone is exposed to from a tanning bed (or booth) depends on the specific lamps used in the bed, how long a person stays in the bed, and how many times the person uses it. Most modern UV tanning beds emit mostly UVA rays, with the rest being UVB.
Phototherapy (UV therapy): Some skin problems (such as psoriasis) are helped by treatment with UV light. For a treatment known as PUVA, a drug called a psoralen is given first. The drug collects in the skin and makes it more sensitive to UV. Then the patient is treated with UVA radiation. Another treatment option is the use of UVB alone (without a drug).
Black-light lamps: These lamps use bulbs that give off UV rays (mostly UVA). The bulb also gives off some visible light, but it has a filter that blocks most of that out while letting the UV rays through. These bulbs have a purple glow and are used to view fluorescent material. Bug-zapping insect traps also use “black light” that gives off some UV rays, but the bulbs use a different filter that causes them to glow blue.
Mercury-vapor lamps: Mercury-vapor lamps can be used to light large public areas such as streets or gyms. They do not expose people to UV rays if they are working properly. They are actually made up of 2 bulbs: an inner bulb that emits light and UV rays, and an outer bulb that filters out the UV. UV exposure can only occur if the outer bulb is broken. Some mercury-vapor lamps are designed to turn themselves off when the outer bulb breaks. The ones that don’t have this feature are only supposed to be installed behind a protective layer or in areas where people wouldn’t be exposed if part of the bulb breaks.
High-pressure xenon and xenon-mercury arc lamps, plasma torches, and welding arcs: Xenon and xenon-mercury arc lamps are used as sources of light and UV rays for many things, such as UV “curing” (of inks, coatings, etc.), disinfection, to simulate sunlight (to test solar panels, for example), and even in some car headlights. Most of these, along with plasma torches and welding arcs, are mainly of concern in terms of workplace UV exposure.
Most skin cancers are a result of exposure to the UV rays in sunlight. Both basal cell and squamous cell cancers (the most common types of skin cancer) tend to be found on sun-exposed parts of the body, and their occurrence is typically related to lifetime sun exposure. The risk of melanoma, a more serious but less common type of skin cancer, is also related to sun exposure, although perhaps not as strongly. Skin cancer has also been linked to exposure to some man-made sources of UV rays.
Your skin makes vitamin D naturally when it is exposed to UV rays from the sun. How much vitamin D you make depends on many things, including how old you are, how dark your skin is, and how strong the sunlight is where you live.
Vitamin D has many health benefits. It might even help lower the risk of some cancers. At this time, doctors aren’t sure what the optimal level of vitamin D is, but a lot of research is being done in this area.
Whenever possible, it’s better to get vitamin D from your diet or vitamin supplements rather than from exposure to UV rays. Dietary sources and vitamin supplements do not increase skin cancer risk, and are typically more reliable ways to get the amount you need.
It’s not possible (or healthy) to avoid sunlight completely, but there are ways to help ensure you’re not getting too much sun:
If you’re going to be outside, simply staying in the shade, especially during midday hours, is one of the best ways to limit your UV exposure from sunlight.
Protect your skin with clothing that covers your arms and legs.
Wear a hat to protect your head, face, and neck.
Wear sunglasses that block UV rays to protect your eyes and the skin around them.
Use sunscreen to help protect skin that isn’t covered with clothing.
Recent research suggests that UV light may have played a key role in the origin of life on Earth, especially the origin of RNA. In a 2017 article in the Astrophysics Journal, the authors of the study note that red dwarf stars may not emit enough UV light to start the biological processes needed for the formation of ribonucleic acid, which is necessary for all forms of life on Earth. The study also suggests this finding could help in the search for life elsewhere in the universe.
Optical radiation from the sun is modified significantly as it passes through the Earth's atmosphere, although about two-thirds of the energy from the sun that impinges on the atmosphere penetrates to ground level. The annual variation in extra-terrestrial radiation is less than 10%, but the variation in the modifying effect of the atmosphere is far greater (Moseley, 1988). Measurements corrected for atmospheric absorption show that the visible portion comprises approximately 40% of the total radiation received at the surface of the Earth. While UVR comprises only a small proportion of the total radiation (approximately 5%), this component is extremely important in various biological processes. The principal effect of infrared radiation is to warm the earth; approximately 55% of the solar radiation received at the surface of the earth is infrared (Foukal, 1990).
Ozone (O3) is a gas which comprises approximately one molecule out of every two million in the atmosphere. It is created by the reaction of molecular oxygen (O2) with atomic oxygen (O), formed by the dissociation of O2 by short-wavelength UVR (< 242 nm) in the stratosphere at altitudes between about 25 and 100 km. Absorption of UVR at wavelengths up to about 320 nm converts the ozone back to O2 and O, and it is this dissociation of ozone that is responsible for preventing radiation at wavelengths less than about 290 nm from reaching the Earth's surface.
Summary:
It is likely that the UV rays are the highest during the Rahu Kalam periods. Hence try to safeguard yourselves and your near and dear ones from unnecessary exposure during this period.
Now relax for few minutes before exiting this blog with a lovely recital in Neelambari:
https://www.youtube.com/watch?v=V3CrHR4ui5I
