April 27, 2010
In the race among physicists to produce direct evidence of Dark Matter, an Italian group announced that they have found signs of Dark Matter from their experiment called DAMA/LIBRA. Then, a US-based experiment called CoGent also found evidence of Dark Matter.
In an effort to reconcile the findings from the two experiments, Liam Fitzpatrick at Boston University suggested that a light, weakly interacting dark matter particle could explain both results. And now, Robert Foot from the University of Melbourne says that the existence of Mirror Matter could explain it better.
In a nutshell, Dark matter, which contains the "missing mass" that's needed to explain why galaxies stay together, could take any number of forms--and Mirror Matter could be one of them.
Most of these ideas are somewhat hypothetical as of yet. At this point I need to clarify that mirror matter is not anti-matter. Whereas anti-matter has more to do with particles of the opposite charge (i.e an electron with a positive charge, called a positron), mirror matter owes it's distinction to parity or chirality. To understand it better, let's use the analogy of left-handed molecules where chirality arises from geometry not composition.
Another difference between mirror matter and antimatter is that anti-matter plus ordinary matter is highly reactive and explosive--both will be annihilated in a burst of energy upon contact. But mirror matter and normal matter reacts so weakly, where the effect of gravity could be the only noticeable "symmetrical" interaction between the two.
Now that you have an idea of mirror matter, here's the mind-blowing aspect of it. The implications of the existence of mirror matter is astounding because when you consider the fact that in the observable universe alone, we already say that there are billions and billions of stars. How much more if there are additional mirror galaxies, mirror stars, and mirror planets? The observable universe that we infer, based on what we have "seen" thus far with our telescopes (like Hubble, Spitzer, etc.), only accounts for 4.6% of the whole universe. Dark matter accounts for 23%! (the rest is dark energy which is even harder to detect).
Even if only a certain percentage of Dark Matter is mirror matter, and if that is proven true--then it will be quite staggering to our imagination.
Think about mirror exoplanets. Think about the kind of life that might arise from planets made of Dark Matter. Think about lifeforms and advanced beings made up of mirror matter. What will happen if you shake hands with a "mirror alien"?
Truly, there is so much we don't know. Our imagination pales in comparison to the unknowns of the universe. And the journey of knowing, and speculating a bit, at each step--is simply a wonderful experience.
First evidence that Mirror Matter from Technology Review
Signs of Dark Matter... from Physorg
The World is your Mirror from www.seanmantey.co.uk