Clay: “Marsden Asteroid”? I thought it was over Edmonton, Alberta?

Anyway, according to recent estimates, that fireball had an approximate mass of 10-tonnes and entered the atmosphere at about 14 kilometres/second — a relatively slow speed, usually meteoroids/asteroids enter the atmosphere at around 20-30 km/s.

Therefore, based on those estimates, its kinetic energy (1/2 * m * v^2) would have been: 9.8 x 10^11 Joules — equivalent to ~234 tonnes of TNT. However, virtually all of that energy was dissipated in the upper-atmosphere.

If you want some fun simulating asteroid/comet impacts on various targets on the Earth, then click on my name and the link will direct you to the “Impact Calculator” web-site. Enjoy!

Well yeah, much, much bigger. Everest is only a couple miles wide. The south face rises 8k ft from above the western cwm of the Khumbu glacier on the Nepal side. The slightly taller north face rises 8500 feet above the Rongbuk glacier on the Tibetan Plateau. Much, much larger than Everest are Denali (US) and Mt. Logan (Canada).

“Marsden” must have packed a mighty punch.

Although I’ve read numerous times about the possibilities of an asteroid plummeting towards earth, every time I do, I’m thrown off…

It is so easy to forget how vast of a Universe we are part of, that our planet is just a tiny piece of such a large picture we are unable to grasp fully.

Gravity pulls & all divertion methods… it is all just freakin’ amazingly scary and awesome how far humans have advanced in their pursuit to keep us spinning with this earth.

And, IVAN3MAN, you amaze me with your mathematical skills!

Alex: Your calculations are somewhat off.

1 tonne of TNT = 4.184 x 10^9 Joules (Source: Wikipedia — TNT equivalent).

Therefore, the 50Mt yield “Tsar Bomba” would have had an energy equivalent of 2.092 x 10^17 J.

Whereas a 1 tonne projectile, traveling at a velocity of 0.01c (3000 km/s), will have a kinetic energy (1/2 * m * v^2) of 4.5 x 10^15 J — equivalent to 1Mt of TNT.

The ‘Gravity Tug’ concept isn’t really all that new, it’s been talked about for a long time. It really is the only reasonable way on the table right now to keep a large rock from hitting us. If you read Phil’s book, he talks about it in great detail and far more eloquently than me.

But, if you boil it down to the basics- everything has gravity. If you have a 20 ton rock and a 1 ton probe, they affect one another. If the probe flys next to the asteroid and begins to pulse it’s engines in the direction we want the asteroid to go. If the rock is five years from hitting us even a small change in it’s trajectory will ensure it misses us when it finally gets to the point in space where we intersect.

If the asteroid is bearing down on us and a few weeks from impact, you’re right- you’d need something of equal or greater mass than the asteroid to make a difference. But when they’re far far away from hitting, you don’t need much to make the changes necessary to keep it from impacting.

The issue at hand, obviously, is spotting it early enough.

Grab a copy of Phil’s book – he explains it far better than me. And, as a bonus, you get all the other fun stuff he writes about!

I think that a more effective proposition would be a Kinetic Impactor — a means of deflecting an asteroid by attempting to directly alter its momentum by sending a spacecraft to collide with the asteroid. Deflection could be achieved with a small mass of <1 tonne up to 10 tonnes to impact against the asteroid, depending on its size.

The European Space Agency is already studying the preliminary design of a space mission able to demonstrate this futuristic technology. The mission, named Don Quijote, is the first real asteroid deflection mission ever designed. During a trade-off study, one of the leading researchers argued that a strategy called “kinetic impactor deflection” was more efficient than others.

For more information, check out “Asteroid Deflection Strategies” in Wikipedia.

Well, that’s my two cents’ worth.

What I witnessed no force on Earth could stop and the dark evening was lit up like the day.If you catch them before earth’s gravity-well you might get a chance to nudge them away.
Once they are drawn down towards us you are a captive audience and powerless.
Thanx-Clay