After a large asteroid recently skimmed past Earth at close range and a large meteor blasted across the sky over Russia, there seems to be a renewed concern about our planet's vulnerability to a cataclysmic impact event. Though such events are rare, they are also inevitable. Countless numbers of large space rocks have impacted the Earth in the past, and they will continue to bombard the Earth in the future.

The real question is: When an asteroid is known to be on a trajectory to impact the Earth, is there anything we can do about it? The good news is that scientists have floated a number of theories, some practical and some not so much, that involve either diverting or destroying an incoming asteroid. Perhaps the coolest of these theories, though, is the recent suggestion by two California scientists that we ought to garner inspiration from science fiction and build a real life Death Star, according to a recent UCSB press release.

That's right: a Death Star — the moon-sized, planet-destroying device from the "Star Wars" movies.

It may sound like an outlandish idea, but the two California researchers, UCSB's Philip M. Lubin and Cal Poly's Gary B. Hughes, actually have the engineering specs to make it into a reality. Their plan, titled "Directed Energy Solar Targeting of Asteroids and exploRation" (which, hint hint, is called DE-STAR for short), proposes building a solar-powered, scalable space array capable of firing powerful lasers at incoming asteroids.

The project also proposes different versions of the DE-STAR technology, which grow more powerful as the technology is developed. For instance, DE-STAR 2 would be about the size of the International Space Station and be capable of firing a laser powerful enough to nudge asteroids and other space rocks away from their impact trajectory. A DE-STAR 4 design, on the other hand, would be about 100 times that size and be capable of actually obliterating an asteroid as large as 500 meters across.

The project also proposes a DE-STAR 6 design, which would be one mean space machine. Though it wouldn't be powerful enough to destroy a planet the size of Earth, you wouldn't want it backfiring. Lubin and Hughes suggest that a DE-STAR this powerful could be used for other, less nefarious purposes. They suggest it could be used as a space-based power plant, and its laser would be strong enough to propel a futuristic spacecraft at near the speed of light.

"Our proposal assumes a combination of baseline technology –– where we are today –– and where we almost certainly will be in the future, without asking for any miracles," explained Lubin.

In other words, don't let the fact that this design has an analogue in science fiction fool you. Lubin and Hughes mean business, and their device could offer a real solution to the inevitable planet-threatening asteroid.

Of course, there are some serious concerns about building a Death Star too. For one, as any fan of "Star Wars" knows, the Death Star in the movies was used to destroy planets, not save them. Even Lubin's and Hughes' more modest DE-STAR designs could be turned into powerful weapons in the wrong hands. Directed back toward the Earth, the lasers could do some serious damage. So there are some concerning political issues worth considering. Such a device would also be extremely expensive to build, and there may be more affordable technologies worth considering that could just as effectively shield the Earth from an incoming space rock.

Plus, given that the odds are fairly low of an impact event happening in the immediate future, we have to ask ourselves whether the risks outweigh the rewards. Nevertheless, Lubin and Hughes mean for their Death Star proposal to be taken seriously.

"There are large asteroids and comets that cross the Earth's orbit, and some very dangerous ones going to hit the Earth eventually," said Hughes. "Many have hit in the past and many will hit in the future. We should feel compelled to do something about the risk. Realistic solutions need to be considered, and this is definitely one of those."

Related space story on MNN: 7 asteroid impact craters here on Earth [Photo gallery]

Bryan Nelson ( @@brynelson ) writes about everything from environmental problems here on Earth to big questions in space.

Scientists propose building Death Star to protect Earth from asteroids
A real-life Death Star might help protect the Earth from asteroid impacts, but it could also become a dangerous weapon for the military.