The answer to this question has to do with the ancient system of planetary hours and planetary days and the division of day and night, each into 12 equal portions of time. There is an unbroken order of the visible planets ruling the 24 hours of a day, and this order is based on the speed of the planets.

The fastest planet is the Moon followed by Mercury and Venus. From a geocentric viewpoint, then comes the Sun, while from a heliocentric perspective it is the Earth. Mars follows, then Jupiter, and the slowest planet is Saturn. Uranus, Neptune and the objects from the Kuiper Belt, like Pluto or Eris, are not visible to the human eye and are not part of the traditional Vedic planetary system.

  • Moon
  • Mercury
  • Venus
  • Sun/Earth
  • Mars
  • Jupiter
  • Saturn

As the Sun is the center of the solar system, the list of the planetary hours starts with the Sun. From the Sun we go up to Venus, Mercury, and the Moon, and then start from the bottom and go from Saturn, Jupiter and Mars back to the Sun:

  1. Sun 
  2. Venus 
  3. Mercury 
  4. Moon 
  5. Saturn 
  6. Jupiter 
  7. Mars

This order repeats itself continuously and gives us the chart of the planetary hours of day and night:

Please note that the Vedic day does not start at midnight but at sunrise. Therefore, the first hour of the day is always the first hour after sunrise. And planetary hours are not the sixty-minute hours that we normally know for time keeping, because the day is split into two periods of day and night, which means that according to the seasons, diurnal and nocturnal hours differ in length, except on the equinoxes when day and night are balanced in length.

You can use an online calculator for the planetary hours for your time zone, or even an app on your phone, if you wish to align the activity that you want to perform with the influence of the planet associated. Let us say you want to write something. That means you would to it on Wednesday, ruled by Mercury, or at a planetary hour ruled by Mercury on whatever day of the week. You would look for Jupiter for a money investment, for Venus for a love spell or enjoying a massage, for the Moon to cook, or for Saturn to clean and declutter, etc.

The seven days of the week receive the name from the planet that rules the first hour of that day. The week starts with Sunday because the Sun rules the first hour of the first day, which is why the Sun becomes the Lord of the Day. As this first day ends with Mercury’s rulership over the last hour of the day and the next planet in the unbroken order of planets is the Moon, the second day starts with the Moon, who becomes the Lord of Monday. The third day is Tuesday whose first hour is ruled by Mars. And then come Wednesday (Mercury), Thursday (Jupiter), Friday (Venus) and Saturday (Saturn).

In the US, Canada, and Japan the week starts with Sunday. But in Europe it has become an unhealthy habit to begin the week with Monday, as done in the USSR. This is not only disrespectful towards the Sun, but it means also to break the Hora and the planetary order. And the Hora, that is the division in day and night and the division of every zodiacal sign into two Horas, has everything to do with our wellbeing in terms of finances, economy, and food supply. The Moon is a very fickle planet and if we use it as the ruler of the first day of the week, it will bring many ups and downs in our life.

Please, do not to use any calendar that starts the week with Monday, and honor the Sun on Sunday as the planetary lord of the first day of the week with a candle and the mantra Ram!