Ep. 32, Page 32

smbhax on Sept. 25, 2017

Physicists observe ‘negative mass’ (BBC) is a news article I've been sitting on since it came out in April, because I was afraid the wig-flipping concept of negative mass would lead me down a more or less incomprehensible hardcore particle physics wormhole that would take me untold hours to even try to navigate my way out of. Fortunately, the Wikipedia article on negative mass is mercifully constrained to the speculatively theoretical, an area I am not usually tempted to trip into.

Which does make the experiment reported in the BBC article all the more noteworthy, it being the first actual case of negative mass being reported in the laboratory. Researchers at Washington State University (in my home state! : D) say that after cooling rubidium atoms to near zero, so that they moved slowly enough to be hit by lasers, which struck them in such a way as to reverse their spin, the atoms took on behavior consistent with what would be predicted of a negative mass: namely, that when pushed (by the lasers? the articles don't say), the atoms, instead of moving with the direction of the push as boring, regular, positive masses do, moved *against* the direction of the push: "With negative mass, if you push something, it accelerates toward you. It looks like the rubidium hits an invisible wall.“

So, that's pretty crazy to my positive mass brain. Does this mean a negative mass would fall *upward* in a gravity field? : o Anyway, until further experiments can duplicate the findings and prove this really does appear to be ”negative effective inertial mass," as Wikipedia called it, we shouldn't get too excited…I suppose. : P