sudas: In another post, several people, including myself were discussing climate change from global warming. This is a thorny subject, because we have limited data, complicated weather systems and consequences for business and society. I thought I'd mention another issue in science that I follow, that does not have such controversial social implications. This is Dark Matter. For some years now, astronomers found that stars at the edge of the galaxies revolve faster than they should about the center. This would be as if Pluto always orbited further than Neptune, but had the same "year." To explain this they came up with the notion of Dark Matter. There are two types of Dark Matter. One is sometimes called Dim Matter, which involves things like planets, dust, brown dwarf stars and such that we can't see. The other type of Dark Matter is stuff that has gravity, but no one has ever seen, and few can imagine. It is not atoms, or electrons, or things we know. There is an alternative put forth in the 1980s. It is called MOND, for MOodified Newtonian Dynamics. It says that there is an +- factor to gravity that only comes about in small accelerations, like stars about a galaxy. Just as Einstein's Relativity changed Newton's laws near the speed of light, and Quantum Physics changed it for the very small, MOND proposes it be changed with small gravitational accelerations (for vast distances). In my opinion MOND seems to be more correct. It has made some predictions which have been borne out, which means it's more than just a scheme to fit the data. Yet Dark Matter, gets nearly all the attention in the press. Discussing Dark Matter is like talking about fairy dust. It will be a long slow fight of gathering and presenting the evidence before Dark Matter is overturned. Scientists can battle it out through experiments. I look forward to seeing how MOND affects calculations such as the age of the universe and the future expansion of same, if true. Fortunately, politicians and industries don't have a stake in which way the science goes, unlike global warming.