Science Frontiers ONLINE No. 132: NOV-DEC 2000 | |
|
|
Many candidates have been proposed to play the dark-matter role. One of the more popular possibilities is that vast sea of neutrinos pervading the cosmos -- if they really do display just a hint of mass. Two other candidates now on the table are so bizarre that we marvel at the ingenuity of the theorists. One involves exceedingly large particles, the other unbelievably tiny clumps of particles.
At the "giant" end of the size spectrum are galaxy-size particles weighing only 10-24 as much as an electron, which is itself by no means large. It would be hard to experimentally distinguish such ethereal particles from a hard vacuum. A Princeton team, led by W. Hu, asserts that such particles would coalesce into giant globs of "fuzzy", cold, dark matter.
Now if only Hu et al would tell us how to detect them! (Pease, Roland: "Globs in Space" New Scientist, p. 5, August 26, 2000.)
So-called "Q-balls" are also candidates for dark matter. Theorists claim that Q-balls were created during the Big Bang and may still be roaming the universe. Far from being ethereal,
Each one is like "a new universe in a nutshell" [A. Kusenko] says. Inside a Q-ball, the familiar forces that hold our world together don't exist. This has some startling consequences. It means that every Q-ball is on a mission to violate law and order in the universe by assimilating normal matter and compelling it to live by Q-ball rules.
Who can deny the exotic nature of Q-balls after that description? Q-balls are so tiny (about the size of an iron nucleus) and move so fast (about 100 kilometers/ second) that they can zip through a planet with scarcely any observable effect. In this elusiveness they resemble neutrinos. As a matter of fact, Japan's Kamiokande neutrino detector, which contains 50,000 tons of water surrounded by a shell of detectors, has been "blinded' several times by the passage of entities that could well be Q-balls. If these bizarre entities do exist, they could be that dark matter that astronomers insist pervades the cosmos.
(Muir, Hazel; "Cosmic Anarchists," New Scientist, p. 22, May 20, 2000.)
Comment. Can astronomy call itself a science when it entertains theories like those above? Interestingly, in the 1920s, geology journals used almost indentical words in connection with another too-bizarre theory: continental drift, which is now a dominant paradigm in geology!
Other Sites of Interest
|