Keeper of the Objects

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Posted by michael on Tuesday July 22, 2003 @01:10PM from the wipeout dept.

cEnTiBeE writes that this is "not about the Matrix," but rather about Near Earth Object tracking. "It's accomplished by a staff of 2.5 people watching to see when any 'vermin of the sky' plan to pay earth a visit. This piece titled Keeper of the Objects is in the August '03 issue of Scientific American."

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Re:Joy by russ_allegro · 2003-07-22 13:56 · Score: 5, Informative

Actually there is a lot more than 2.5 watching the skies. The Minor Planet Center takes data from amatuers as well as their own automated telescope. It is true that the MPC keeps and processes the data. Although ametuers are known from time to time to do their own orbital calculations.
Actual Frequency of Impact by thelandp · 2003-07-22 14:53 · Score: 5, Informative

There's a relationship between asteroid size and predicted frequency of impact.
10m - every 1-5 years
100m - every 1000 years
1km - every 100,000 years
The Tunguska blast of 1908 was a roughly 100m asteroid, hitting land.
If it had been an ocean impact, it would have produced significant tsunamis.
On the remote chance it had landed right on top of a large city, then the city would be completely gone.
A 1km asteroid would wipe out a moderate US state, or create tsunamis that travel to most of the globe. Either way it would affect the climate due to dust clouds.
The observational population census for Earth crossing objects is only complete for objects in the 8-kilometre diameter range (such as 1627 Ivor) or larger. The detection completeness for 1 kilometre range is estimated to be in the region of 12%.
(further reading is here)
Maybe it's worthwhile upping the budget so we can track all of them down to 1km ?

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-- the only thing we have to fear is really scary things
1. Re:Actual Frequency of Impact by bravehamster · 2003-07-22 15:44 · Score: 5, Informative
  
  The Tunguska blast of 1908 was a roughly 100m asteroid, hitting land.
  
  Kinda a' nitpick, but the Tunguska object didn't hit land, it was an air-burst. That's the reason there isn't a huge crater there now. It flattened all the trees for hundreds of square miles, but in the very center of the blast, no crater. Stumped a bunch of scientists for a good long while. Air-burst detonations have a larger area of immediate effect (i.e. flattened by the blast wave), but their global effect is less than ones that actually impact. Either way you get lots of knocked over trees and some pretty sunsets.
  
  --
  ---- El diablo esta en mis pantalones! Mire, mire!
2. Re:Actual Frequency of Impact by mikerich · 2003-07-23 04:36 · Score: 3, Informative
  
  The Tunguska blast of 1908 was a roughly 100m asteroid, hitting land.
  It was at most 50 metres across and made largely of ice, it would never have made it to the surface.
  If it had been an ocean impact, it would have produced significant tsunamis.
  At 15 megatonnes it wouldn't have raised much more than a ripple. The US exploded larger bombs at sea level.
  The rest of your point is well taken though, although you left out one bit. Would Dubya, Putin or our little poodle in the UK wait to confirm the source of an explosion that took out one of their cities before launching a nuclear attack against their evil guy of the week?
  Best wishes,
  Mike.
Re:The scary asteroids. by Jafafa+Hots · 2003-07-22 15:01 · Score: 2, Informative

can you sum up what this loony claims? The web site is too painful to try to navigate...

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This space available.
Re:Besides USA by Anonymous Coward · 2003-07-22 15:21 · Score: 2, Informative

Well, just to bore everyone with more news from Australia: Not us.

Our ever-so-enlightened-and technically-aware government killed all funding for this kind of thing. Plus, one of our optical telescopes, Mt Stromlo, recently burned down (at least its going to be rebuilt).

Unfortunately, ours was the only program of its type in the southern hemisphere (according to the press; I hope that's not true though).

Keep watching the skies...you never know when you might need to duck.
Re:Joy by joebeone · 2003-07-22 16:57 · Score: 3, Informative

As an astronomer, I can say with confidence that those 2.5 people probably do a lot more of technological babysitting than actual not-enough-time-in-the-day work... objects are found by computer software that compare image residuals (subtractions of images separated by a day or two)... fast moving things are closer to earth and may warrant follow-up with a larger 'scope.