|
|
Lu, a 1984 graduate of Cornell with a bachelor's degree in electrical engineering, was introduced to the large audience by University President Jeffrey S. Lehman. The two had talked before by ham radio last October when Lu was spending six months in Earth's orbit aboard the International Space Station (ISS).
Lehman had asked Lu if he could take a photograph of Cornell when the space station passed over the university, but Lu replied that every time he did, the place was clouded out.
Lu has flown on three space missions in four different space vehicles since 1995. Lu used his astronaut experiences and images from the ISS to highlight his talk, titled "Rocketships, Dinosaurs, Asteroids, and Immortality."
Using a large screen at the front of the arena, Lu displayed photographs of giant impact craters taken by him from Earth's orbit. The astronaut described the various types of natural space debris that have and could affect our blue planet.
While most meteors that hit Earth every day are dust particles that quickly burn up in the atmosphere, some pose an actual threat to life on this world. On the lower end of the scale, space rocks averaging 60 meters across tend to strike about once per century and explode in the air before reaching the ground. A prime example of this type is the one that hit the Tunguska region of Russia in 1908.
It destroyed 200,000 square miles of Siberian forest in the process. Thankfully the remote area was sparsely populated.
At the high end of the scale, asteroids five miles wide or more do not cross Earth's path around the Sun more than once in millions of years, but when they do, whole species can be wiped out.
Just ask the dinosaurs who lived on our world until 65 million years ago.
Lu compared this devastation and loss at the end of the Cretaceous Period to "turning off your computer without saving your work."
Should such an object strike Earth today, civilization as we know it would be gone. To drive the point home as to what could be lost, Lu displayed images of some major cities and human constructions that he saw from 240 miles above Earth's surface. This included Ithaca and Cornell, which Lu eventually got to photograph during his ISS mission.
Fortunately for everyone, scientists, engineers, and astronauts such as Lu have been thinking of ways to prevent this disaster from happening. Though recent films on the subject show astronauts blowing up threatening space rocks, Lu states that nudging these asteroids into a new solar orbit is the safer way to go.
Lu helped to found the B612 Foundation (www.b612foundation.org), named after an asteroid in the famous story The Little Prince by Antoine de Saint Exupry.
Their goal is to use an electric-powered space tug that would push an offending asteroid just enough - perhaps as little as one centimeter per second (0.03 miles per hour) - to divert the object into an orbit that would miss Earth for ages to come. The technology could also be funded by and used for commercial purposes in the development of a space infrastructure for industry, exploration, and colonization.
