Broadcast 3101 Dr. Kirsten Howley

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Guest:  Dr. Kirsten Howley;  Topics:  Asteroid defense mitigation, Project HAMMER, thermal nuclear devices, asteroid sizes & distance mitigation needs, black holes, physics, time travel, entropy, Big Bang & so very much more!  Please direct all comments and questions regarding specific Space Show programs & guest(s) to the Space Show blog which is part of archived program on our website,  Comments and questions should be relevant to the specific Space Show program. Written Transcripts of Space Show programs are a violation of our copyright and are not permitted without prior written consent, even if for your own use. We do not permit the commercial use of Space Show programs or any part thereof, nor do we permit editing, YouTube clips, or clips placed on other private channels & websites. Space Show programs can be quoted, but the quote must be cited or referenced using the proper citation format. Contact The Space Show for further information. In addition, please remember that your Amazon purchases can help support The Space Show/OGLF. See

We welcomed Dr. Kirsten Howley to the program to discuss planetary defenses against an incoming asteroid threat plus many additional topics.  During the first segment of our 94 minute program, Dr. Howley introduced us to asteroid threat mitigation using the concept known as Project HAMMER.  As you will hear, Project HAMMER relies on a thermal nuclear device to deflect or in an emergency, disrupt an asteroid to keep it from colliding with Earth.  During the first part of this segment, our guest explained the nature of the threat, the issues raised by asteroids of different diameters and different distances (time) from projected Earth impact.  We talked about various intervention strategies including the kinetic impactor, Project HAMMER for deflection, the last ditch effort known as the disruptive strategy, a longer term possibility known as the gravity tractor, and the ongoing effort to research and develop additional technologies to solve the asteroid threat problem.  Dr. Howley talked about each of the above strategies in some detail.  Many listener questions came in on a wide range of topics.  For example, Bill from VA wanted to know exactly how a nuclear thermal device explosion would work in front of an asteroid given space being a vacuum and the fact that there are no shaped nuclear explosions.  Our guest responded in detail to Bill's questions so don't miss what she said as she explained how HAMMER would actually work in space to deflect an incoming asteroid.  Our guest was asked about possible side effects of setting off a thermal nuclear device in space.  For example, could an EMP travel to Earth or could Earth somehow get enhanced radiation or something like that.  As you will hear, no side effects for Earth but don't miss all of what Dr. Howley had to say on these subjects.  She did explain the difference in how the impactor would help deflect the asteroid as compared to the HAMMER explosion.  Don't miss how she said all of this would work.  Key to these strategies was how much time there would be until the asteroid hit Earth.  We talked 100 year time lines down to about 2 years out.  We also talked asteroid size.  Later in the discussion, you will hear Dr. Howley talk about the peak asteroid size being 300 meters in diameter.  Don't miss what she said about this peak size and why it was the peak size.

Additional first segment topics included the gravity tractor (very slow so it would require lots and lots of advance warning to be effective), radar guidance to the asteroid and remotely setting off the explosion, planetary defense, asteroid bio contamination of Earth, standoff distances from the asteroid as required by the various mitigation strategies, the possibility of using asteroids as a weapon, exotic propulsion including nuclear propulsion, radiation risks, launch windows for getting to the asteroid, international HAMMER participation, plus a few others.  Many of these topics were a result of listener emails.

In the second segment, we talked about the issue of deflection timing.  This was key to understanding how to deflect an asteroid.  I had some trouble with it but by persisting in asking questions about it, I finally got it so I hope all of you understand deflection timing issues.  The subject of laser mitigation came up both from a listener and myself.  I asked about using one of the powerful laser beam launch technologies talked about in the Breakthrough Project for interstellar flight.  Dr. Howley said that laser ablation had been looked at but that laser intervention was not applicable at this time.  We also talked about asteroid sample return missions of which a few are underway or in the planning stage. 

We switched topics to additional topics of interest to our guest and listeners.  For example, we talked about black holes from the perspective of an observer and a person falling into a black hole.  This included a discussion about worm holes and white holes and the Big Bang.  Don't miss it.  We had a similar conversation about falling into Jupiter.  Since we know that Andromeda and the Milky way will someday collide, Kirsten talked about galaxy collisions and galaxy cannibalism.  She told us what to expect here on Earth when the Milky Way gets cannibalized by Andromeda way off in the very distant future.  Time travel was a subject (a favorite of mine) and we touched on dark matter and dark energy, saving some of the discussion on physics and other topics for a return visit by our guest. 

Before our program ended, we talked about the risk of the nuclear explosion shattering the asteroid into lots and lots of smaller pieces with the potential of hitting Earth.  Kirsten talked about this possibility and explained the disruptive technology to shatter an asteroid as a last ditch effort to keep a big rock from hitting Earth.  In the end, there might be less damage to the Earth by chunks of the asteroid getting through our atmosphere and hitting different places on Earth but not destroying Earth whereas the big asteroid, if left untouched, might end up producing a planet killing impact.  Orbital planes were discussed, time travel and entropy were discussed and when I asked our guest what we left out, Kirsten said she was surprised by no questions pertaining to comets.  We spent the last several minutes of the program talking about comets, possible comet collisions with Earth, and possible comet intervention strategies.

Please post your questions/comments for Dr. Howley on TSS blog for this program.  You can reach Dr. Howley through me or via the Lawrence Livermore National Lab website.




Asteroid deflection with Project Hammer & much more

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16 Apr 2018 Dr. Kirsten Howley
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