Does the Sun have a brown dwarf companion way out there we cannot see?
I'm not an expert in this area, but astronomy has progressed to the point where even the smallest perturbation that such a thing would generate would probably be detected.
Are there any large quantities of gold and platinum in any NEAs that could be reached by Orion. (greed could spark a new gold rush into space).
I did a short article on this once. I can't reproduce it here because I can't insert PDFs, and this format stinks for tables. But based on the assumption that large nickel-iron asteroids (somewhat uncommon) have a similar composition to fragments that fall to Earth as meteorites, the results were impressive.
A half-mile diameter object of this type would contain an amount of gold equivalent to about three percent of all the refined gold ever mined on Earth. The amount of nickel and cobalt in that asteroid exceeded the 1985 world known reserves by four or five times.
Space/Science » in reply to Cool list! Here's mine
A couple of answers