Anomaly

An 'anomaly' is an incredibly powerful magnetic event that exists in four-dimensional space. Anomalies act as portals between two points in space-time, and most are large enough to allow the passage of objects, creatures and even gases and liquids through them. An anomaly is also able to create disastreous atmospheric changes as shown in the sixth episode of the fifth season of Primeval, where the New Dawn anomaly that led to the Sterile Earth Desert Future, caused a atmospheric change due to the massive climate differences.

The word 'anomaly' was coined by the Anomaly Research Centre.

Description
Anomalies take the form of flickering orbs of light, usually suspendended about 1.5m above the ground, orbited by thousands glass-like shards. They flicker more frequently as they weaken, and then suddenly collapse once the magnetic energy drops below a certain threshhold.

Effects
Anomalies exert a very strong magnetic field. This field is so powerful that it can actually pull ferrous metal objects out of people's grasp, and through the anomaly. The momentum gained is high enough to propel the objects out of the anomaly's sphere of influence.

The intense magnetism also produces interference on the radio wavelength 86.7 FM. This effect can be used to detect anomalies, either simply (using a handheld radio tuned to the correct frequency) or in more advanced methods (using a computer to detect interference on multiple radio aerials and then triangulating the position of the interference's source).

Causes
Not much is known about what causes anomalies to open, or why they appear. Certainly they must be linked to the Earth's magnetic field, as they travel with the Earth in it's orbit instead of being left behind in space as a conventional wormhole might be.

Some areas feature a particularly high rate of anomaly occurance. These are known as focal points. The anomaly rate changes over time. In some areas, exponential anomaly growth is encountered, resulting in a place known as a Spaghetti Junction. These junctions feature tens, hundreds or even thousands of anomalies all open at the same time. It is unknown what effect this has on the timeline at the hands of anachronism.

One theory as to the cause of the anomalies is that they occur whenever timelines intersect.