Now you're just plain making stuff up... "between the size of the solar system and the galaxy":
From: http://en.wikipedia.org/wiki/Key_size
From: http://wiki.answers.com/Q/What_is_the_total_surface_area_of_Earth
The surface area of the Earth is 510,065,600 km2.
1 km is 1,000,000,000,000 mm2
So the surface area of the Earth is 510,065,600,000,000,000,000 mm2
I'll give you the benefit of the doubt in this discussion and say we're only searching water, which is roughly 70% of the Earth
So, that's 357,045,920,000,000,000,000 mm2 you have to search.
An 80-bit number (remember 160 bits only gives you 80 bits of security against a quantum computer) represents
2^80 = 1,208, 925,820,000,000,000,000,000
That's only 2 orders of magnitude harder.
Said another way. If searching the water covered portion of the Earth is "totally possible right now", then I would think something only 2400 times harder would be FAR from requiring a computer "between the size of the solar system and the galaxy".
Especially with the computing power of CPUs doubling every 6 months.