Negative masses in the simulator?

[testtubegames]

Was reading New Scientist today, and came across this article -- Light can break Newton's Third Law...

It's your standard extreme headline, but what researchers have done is play around with the 'effective mass' of photons. Which is really just a stretched analogy for mass (something about how fast the photons pass through a crystal, and how this speed particularly depends on the energy). The cool part is that they can make photons with negative 'effective mass'. And then interact them with photons with positive 'effective mass'.

Science!

The article goes on to discuss what we all now know -- and that is things get strange when negative and positive masses interact. In the experiment, it's more about (quasi) collisions instead of gravity... but the results are basically the same as ours. Positive and negative masses can just accelerate and accelerate in a very non-Newtonian-feeling way. Of course, it doesn't break Newton's Law or anything... so boo to the misleading title. But cool application of what we discussed here!