Rahu & Ketu are the lunar nodes which remain in a horoscope at 180 degrees apart. These are the two shadow planets which always move in retrograde motion. That is, they move backward in the clockwise direction while all other planets move in the anti-clockwise direction in the chart. The astrological signification of it is that Rahu & Ketu are the two eclipse points of Moon. Moon is the 'manas'- the mind through which we feel all emotions and experience life. This is the reason that Rahu & Ketu have an immense psychological effect on the human mind. Rahu reveals the point of obsession in your life. Rahu & Ketu are the karmic planets. Whatever you desired in your past lives but couldn't achieve becomes your desire in this life. Rahu is synonymous with, whatever you couldn't achieve in your past life karmas and you obsess for in this life time. Unless you conquer or achieve it, you wouldn't be satisfied in this life. Thus, Rahu denotes the areas of dissatisfactions in life 

For instance, if Rahu is placed in your 5th house, may face issue with progeny. You may not have children. But Rahu gives you longing for kids. Based on how Rahu is placed in your chart, this passion to have kids can turn into a positive trait. Like, you may start working into kids related field or love kids around you. An evil Rahu on the contrary may push one into even committing crimes against children. The psychological plane of the native is altered by the Rahu as per its association in a chart.

  

Ketu is the 'Point of Renunciation' in the horoscope

Let's understand Ketu now. It is completely opposite to Rahu. Rahu obsesses and Ketu believes in renunciation. If you have Ketu in your seventh house, you may have a very attractive personality, but none of your relationships would seem to work out and at some point in your life, you may start feeling that you wouldn't want to marry or get into a committed relationship.

Ketu has conquered all material things in the past lives and thus is left with no desire in this life/ Janma. The point of presence of Ketu in your horoscope denotes the areas you just don't care much about. Ketu is spiritual in that sense.  

Rahu / Ketu in Gemini / Sagittarius Axis

The axis that Rahu & Ketu are transiting in is very crucial. It remains for eighteen long months, but the results effect you much longer. Rahu does particularly well in the sign of Aries, Gemini, Virgo and Capricorn. Ketu is well placed in Scorpio, Sagittarius & Pisces. 

If we look back into history the time when Rahu - Ketu held this position, some defining changes had come up in the world. It included the biggest earthquake in India in the last 50 years in Gujarat, defeat of Taliban, major recession in the USA, entry of China into WTO & discovery of Human Genome sequence. 1945 saw bombing of Hiroshima, assassination of President John Kennedy in 1963 and September 11 twin tower attacks in 2001. The stage seems set for Rahu & Ketu to continue the story from where last left off in 2001.

How you had done during the last cycle of Rahu/ Ketu in this axis in the years of 2000-01 will help you get some cues to the results of the two karmic planets transiting in your horoscope in the sign of Gemini & Sagittarius. It would vary for every one of us. But one thing common to all is the CHANGE - which is in store for all of us.