The U.S. Navy's latest innovation comes in the form of a 23-pound projectile that can fly at seven times the speed of sound, and it will be ready for testing at sea by 2016.

That's fast enough to travel from New York City's Empire State Building to Philadelphia's Liberty Bell in 180 seconds. The projectile can punch through three walls of reinforced concrete and annihilate just about anything it smashes into. It moves so quickly, in fact, that it doesn't require a triggered explosion on impact; its sheer force is enough to destroy its targets.

Chris Johnson, a spokesperson for Naval Sea Systems Command, told Mashable these recently revealed projectiles will hopefully be able to hit incoming missiles, overhead planes, other sea vessels and targets on land. The small projectiles come equipped with a navigation system that will let them hone in on incoming rockets and vanquish them before any damage is done.

The projectile's power comes from a rail gun, a Star Wars-like weapon which use electricity to launch projectiles down a pair of tracks. Think of how a train starts moving: Once the projectile gets going at mach seven, it packs a punch equivalent to “a freight train going through the wall at a hundred miles an hour," Chief of Naval Research Rear Adm. Matthew Klunder told Breaking Defense.

The projectiles can only travel about 100 miles, which is enough to keep ships out of range of most rockets fired from land, even if it's not close to the 1,500 land miles that the Navy's standard cruise missiles can fly for.

That matters less when price comes into play. At $25,000, these tiny projectiles cost about 1% of what the price of a conventional Navy missile. Those numbers are even more eye-catching, given that the Department of Defense's budget is shrinking.

The Navy hopes to load a rail gun onto a ship for the first on-the-water test shots by 2016, according to Johnson. Rapid-fire trials won't happen until 2018, and no date is set for actually installing a rail gun on a ship. After 2018, the Navy will come up with a timeline for designing a ship with the weapon built in.

While that unfolds, naval researchers will also be developing a 2.0 version of the rail gun. The hope is that this one will be better suited for rapid fire and also able to withstand the intense heat that comes from launching successive rounds.

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