Data from the infrared telescope WISE has now identified ninety percent of the largest near-Earth asteroids.
NASA researchers also downgraded their estimate of the number of medium-sized asteroids, saying there are 44 percent fewer than previously believed. The downside is that scientists have yet to find many of these mid-sized asteroids, which could destroy a metropolitan city.
How can they possibly say that they’ve found 90% of the near Earth asteroids, when there are still undiscovered ones? Isn’t this a complete guess? It reminds me of the old stupid question ” How many undiscovered caves are there?”