NASA is sure that there will be no end-of-the-world on Dec 21 and the Mayan Calendar calculation is wrong. The majority believe that the date only marks as a new cycle of time, and they believe Mayan does not actually qualify as an apocalypse.
There are two scenarios on the effect of an end of the world event on technology.
The Solar Flare and CMEs
This phenomenon that could happen would be a sudden brightening of the sun observed over its surface or the solar limb. The flare would eject clouds of electrons, ions and atoms through the corona of the sun into the space.
On August 9, 2011, a massive x6.9 class solar flare was captured on video by scientists. The effects of the solar flares are very dangerous to spacecraft, astronauts and cosmonauts because of radiation hazards.
Corona Mass Injections or CMEs are massive burst of solar wind and magnetic fields rising above the solar corona or being released into space. Massive solar flares plus CMEs can trigger geomagnetic storms that will knock out electric power for extended periods of time.
Recently, the Murchison Widefield Array radio telescope in Australia detected flares on the sun's surface that could potentially damage communication satellites, electricity power grids and GPS navigation system.
Scientists around the world are calculating how big would be the next Solar Flare with CME and when will it actually hit the earth. So far, they are divided on the fact of when it would happen and it is being linked with the Mayan Calendar which has scared different groups.
If a massive solar flare with CME with that magnitude hits earth, space satellite would go off, stock markets will shut down causing chaos and panic in the business world, telecommunications will disconnect everyone, and power grids will stop supplying electricity worldwide. The result is devastating and chaotic, bringing back mankind temporarily to dark ages until the problem is solved. However, the big if is if the Solar Flare will reach Earth.
This is one of the anticipated phenomenon expected to happen as well which will lead to possible collision of celestial bodies in space. In astronomy, syzygy is a straight line configuration of three celestial bodies in a gravitational system. The Sun, Earth, and either the Moon or a planet are referred to this phenomena. Solar and lunar eclipses are common to occur at times of syzygy.
One loosely event connected to this was on March 21, 1894 at around 23:00 GMT when Mercury transited Sun as seen from Venus, and Mercury and Venus both simultaneously transited the Sun as seen from Saturn.
Such gravitational effects are still being studied especially if the Earth would be involved. Moonquakes, which are similar to earthquakes, put gravitational stress on the Moon during Sun-Earth-Moon syzygy.
End-of-the-world syzygy is the alignment of all planets in the solar system when the systems will pull each other by gravity possibly leading to tides, earthquakes, volcanic eruptions, change of pole and axis, and collision between celestial bodies.