Time stream


 * This article is about the cosmological concept. For the novel see Time Streams.

A time stream defines the time continuum of each of the multiverses. A time stream can be imagined as a constantly extending line, with a beginning at the starting point of the multiverse's existence, and a lengthening end-point which represents the current, global time in the multiverse. Each point between the beginning of the line and its end represents one moment of the multiverse's history.

Slowing and quickening
Failed experiments by Urza on Tolaria resulted in fast and slow bubbles of time. These can be considered as locally condensed or diluted parts of the time stream.

Interactions of time streams
There are infinite time streams, and each of them represents one reality containing a multiverse. Because their amount is infinite, some of them are exactly the same, others differ only in some details or historical period (their global times can flow with varying speed), yet others can be completely different.

New time streams can appear spontaneously, but can also collapse, mostly as an effect of some cataclysm in the multiverse (usually connected with its Nexus). Some of the time streams fray, branch, or intermingle. Usually then, time streams are autonomous or affect each other in ways that are not dangerous for their existence. However, in some circumstances their interactions are hazardous. Especially when time rifts come into existence, bridging alternate time streams, seemingly those most similar, possibly neighboring ones. Rifts are very dangerous, creating serious temporal stresses and can cause a collapse of a time stream, so the end of existence of multiverse it carries.

The Temur shamans of Tarkir speak of the past, the "now" (the present), and the "unwritten now" (the future). They are seeing the past and the various possible presents all at the same time. In the old timeline, Chianul saw a Tarkir that was dominated by dragons. Arel, in the new timeline, saw a Tarkir where the dragons have fallen and Tarkir is ruled by khans.

Travels in time
Although extremely rare and dangerous, it is possible to travel backward in the time stream to the past. Traveling forward in time would be phasing, which removes an object from the time stream (so from existence) for a specified length of time. Unphased objects don't feel the flow of the time in one moment it appears in the future although thousands of years might have passed.

For a long time, the only being known to travel backward in time (even several times) in the multiverse of Dominia was Karn. When Urza started research on time travels, he found out that following temporal stresses will kill any creature having a natural body even that of planeswalker. Experimenting with different kinds of materials Urza declared that silver is the most resistant element for temporal stresses. That's how Karn was created as a probe for tests on time travels. Urza's experiments didn't let Karn do very long jumps. Before the explosion of Urza's time machine, Karn could move just one day back in time. But thousand years later, when Karn became the embodiment of the Legacy, hundreds of souls, minds, and planeswalker himself, he repeated this achievement on a much larger scale and without external machines. This time he moved hundreds of years back in time.

The second person to travel back through time was Sarkhan Vol. Using Ugin's Nexus on Tarkir, he traveled 1,280 years back in time to the pivotal fight between Bolas and Ugin.

The exact mechanisms of time travel are not known, but judging from their descriptions, it can be said that after moving back in time, the history is overwritten by the new version to the point of multiverse's "present." However, while Sarkhan's actions altered the history of Tarkir, they didn't affect the rest of the Multiverse. It is not possible to stay in the past, because the time stream presses on the traveler like a current of a strong river. Because the costs of the energy needed to stay there are enormous and travelers have finite supplies, the time stream will eventually return them to their natural period of departure.

It is not known how paradoxes are resolved. However, it was noted that they cause temporal energies to accumulate in rifts, threatening to collapse the time stream, or speeding this process up.

Clockworking
According to Tezzeret in the canonically contested novel Test of Metal, mages known as clockworkers treat time as a spatial dimension; they can easily jump back and forwards in time like other mages teleport room to room. Such a person is also powerful enough to control the personal temporal flow of people, slowing or speeding up time (making you die by growing old really fast). Tezzeret illustrated the concept of moving sideways in time. Comparing time to a braided rope he explained that every time you make a choice you split off a new temporal strand, some of which will return to the mainline and some of which will go to different ones (basically infinite alternate timelines - although only the more "local" ones close to your main thread are accessible to you). A master clockworker can choose whichever timeline they like, basically selecting the outcome of any encounter. The only limits to clockworking are the power of the adept and rules of probability - the more improbable an event is, the more power it requires to know about and access the alternate timeline where that event occurs.