Ed Lu, "The Last Killer Asteroid"

This lecture was presented as part of The Long Now Foundation’s monthly Seminars About Long-term Thinking.

Anthropocene Astronomy: Thwarting Dangerous Asteroids Begins with Finding Them

Tuesday June 18, 02013 – San Francisco

Video is up on the Lu Seminar page for Members.


Audio is up on the Lu Seminar page, or you can subscribe to our podcast.


The last killer asteroid- a summary by Stewart Brand

Kevin Kelly wrote the following about Ed Lu’s Seminar About Long-term Thinking (SALT) titled “Anthropocene Astronomy: Thwarting Dangerous Asteroids Begins with Finding Them”…

Last night’s SALT talk was one of the most important ones we ever hosted. For several reasons:

  1. Nine years ago, SALT hosted Rusty Schweickart’s talk on the long term asteroid problem, wherein he presented the problem and challenge. Now nine years later, Ed Lu presented a very workable solution. There’s an arc of thinking big over a span of time that we participated in.
  2. While most SALT talks focus on problems, last night’s was extremely focused on a solution.
  3. The solution itself is a (workable) long term project, that has a delayed gratification.
  4. The problem being solved is neither trivial nor superficial but complicated and existential. It’s a big deal.
  5. If B612 was not already doing this, it would make a perfect Long Now project.


I agree. Consider this summary a pitch to donate to the cause. I’ll end with a link to B612’s website.

Lu began by noting that deflecting lethal asteroids is the easy part. We know how to do it and already have the needed technology. Years before a threatening asteroid converges with Earth, we can ram it from behind with a rocket with the precise amount of energy needed to speed it up just enough to miss our planet and keep on missing us in the future.

Funding such a mission will be straightforward. Once you know when (and even where) a catastrophic impact will occur, there will be abundant motivation to pay for heading it off. With good sky reconnaissance, we’ll have years of warning. But that reconnaissance doesn’t exist yet.

Detection of asteroids is the hard part. There are about a million near-Earth objects (NEOs) of dangerous size (over 50 meters), but only one percent of them—10,000—have been located so far.

The best way to locate the rest is with an infrared-detecting telescope following Venus in its orbit around the Sun, looking outward to Earth’s orbit. With the intense radiation of the Sun behind it, the telescope can detect the infrared glow of asteroids and precisely gauge their size and orbits, building a detailed threat map good for centuries.

What are we looking for? Asteroids that Lu calls “city killers” are about the size of a theater—an airburst of one could destroy the whole San Francisco Bay Area. “In our children’s lifetime the chance of impact from one of these is about 30 percent.” In the same period there is a 1 percent chance of an asteroid impact equivalent to all the bombs in World War II times 5; it could kill 100 million people. “We buy fire insurance against risk with lower probability than that.” Then there’s a kilometer-size asteroid, which would destroy all of humanity permanently. The chance of collision with one in our children’s lifetime—.001 percent.

No government has stepped up to detecting asteroids in the detail needed, so astronauts Rusty Schweickart and Ed Lu and their B612 Foundation set about doing it with non-government money and non-government efficiency. The cost and schedule for getting a superb telescope designed, built, and in the orbit of Venus is $200 million, 5 years. The telescope, called Sentinel, has been designed by the world’s best space telescope crafters. Coordination with (highly enthusiastic) NASA has been worked out. Launch is planned for 2018.

Now it’s a matter of funding. The current milestone goal is $20 million. For perspective, Lu reminded his San Francisco audience that the refit of the city’s Museum of Modern Art, now underway, is expected to cost $500 million and be good for about 50 years. At half the cost of a refreshed museum (a worthy cause), the funders of Sentinel can save the whole world, permanently.

B612’s website is here.

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