Or a turbolaser such as the ones on the surface of the Death Star?
According to the trailer for the new Star Wars Rebels Season #2, you can indeed deflect a TIE-Fighter blast with a lightsaber.
In the EU novel Allegiance, Mara Jade uses her lightsaber to block a bolt fired by a scout walker, a considerably smaller vehicle than a Death Star, and similar in size to a TIE Fighter. While she succeeds in deflecting the blast, the kinetic force is so great it nearly wrenches the weapon from her hands. So while it is theoretically possible that a lightsaber could block a blast from a TIE Fighter, it's something that would only work under perfect conditions, and you wouldn't get the chance to block a second shot.
There isn't any particular reason that a person couldn't make a lightsaber large enough to block a blast from a ship-to-ship turbolaser turret, though the power consumption would be problematic. The issue, however, as proven in Allegiance, is the kinetic energy of the blast. A handheld blaster rifle fires a blast that has a very low kinetic energy signature, but a turbolaser is a whole different order of magnitude. It is possible that a strong Jedi, possibly something like a Duinogwuin, could block a small repeater blaster emplacement, like a E-Web (basically the Star Wars version of a Gatling gun) but anything beyond that isn't feasible.
The canon novel Lords of the Sith suggests that a lightsaber could not only deflect a blaster bolt from a TIE fighter, but from larger ships as well. The wielder does have to deal with the much higher kinetic energy from such a bolt, though:
Noses down, the freighters began firing from blaster cannons mounted on the top and bottom of the ships, long red lines that exited the ship in superheated pulses. Trees one hundred meters from Vader and the Emperor exploded into splinters under the onslaught, and the lines cut a rapid path along the clearing toward them, putting a patchwork of smoking holes in the earth, closing in on Vader.
One with the Force, Vader held his ground and tensed for impact. Then he exploded into motion, his lightsaber humming as he spun it rapidly left and right, deflecting the powerful blaster shots off into the forest, shattering still more trees, destroying the tents, but sparing the communications array. The kinetic energy from the shots drove him backward, his boots putting furrows in the soft soil.
The Royal Guards, momentarily taken by surprise, recovered enough to plant blaster rifles against their shoulders. They fired at the freighters as the large ships sped over and past them, but the personal weapons did no harm to the shielded and armored ships.
- Lords of the Sith, p. 168
The freighter type is not identified, but they are described as "large ships" and they have top/bottom blaster cannons like the Millennium Falcon, so they are probably comparable in size and armament to the Falcon (which is much larger than a TIE fighter and able to destroy one with a single blast).
Laser beams are light, by definition. You can't see light coming at you. Once you see it, it already hit you. At least in this universe and with the physics we know.
protected by Community♦ Oct 2 '14 at 1:15
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