Since mass exists, canthere benegative mass?
By definition, mass is the quantity of matter that a body contains. But, could there be negative mass? That seems counterintuitive right? How can you have negative two kilograms of something... Negative mass seems to violate the laws of our universe… But, in 2014 a couple of excited researchers did some calculations and found it was A-OKAY. The Universe is fine with negative mass as long as that mass isn't’ solid. If it’s a fluid, you’re cool.Science pun. So… Negative mass can exist. According to their calculations, a perfect fluid -- which doesn’t exist -- would allow negative mass to exist and wouldn’t defy the laws of general relativity! I know that’s complicated, but put a pin in that for a second. Because just recently in 2017… Researchers used a superfluid to create something with “effectively” negative mass. In spite of what the media is saying (even in the university's own press release) the researchers never said they created negative mass. Instead, the actual paper says they created “negative effective mass” What really happened, as I understand it, they created a Bose-Einstein condensate that behaves unexpectedly, k moving in a way that makes it seem like or that is similar to something with negative mass -- but it doesn’t actually have negative mass. Sidebar: This is a problem in science journalism, it’s easy to get excited and miss a key detail. In science (and journalism) details matter. This has been said by you all in the comments, by other science communicators, and even John Oliver. Science is hard. End sidebar. With that in mind, again. This isn’t negative mass, it’s a Bose-Einstein condensate that behaves as if it had negative mass. As in when this superfluid moves it does so in an unexpected way. But it does have mass, the superfluid was made of 10,000 rubidium 87 isotopes -- so it has the mass of that. Get it? Totally. But c’mon, I know you’re all nerds out there, but you didn’t tune in to learn about how a trapped supercooled superfluid behaved weirdly... so that closes that. Now, remember that pin… let’s snag it. What if they had created negative mass? What would it be like? What would it look like? ALL THE WHAT?! To be honest, no one really knows. Negative mass was first theorized by Einstein early in the last century while coming up with general relativity. A handful of essays published in the 1950s coined the idea of negative mass, as an opposite to positive mass. So, scientifically, it’s a relatively new concept. Some of the papers say something made of negative mass would still have momentum, and be subject to some limits of physics, but would also violate Newton’s Third Law of motion, the equal and opposite reaction one. If you pushed a weight made of negative mass, it would move toward you. But, I read one 1986 article by John G. Cramer, a physics professor at the University of Washington -- and he described it like this: “Consider a pair of equal and opposite positive and negative mass[es] placed close to each other,” he wrote. “The negative mass is attracted to the positive mass, while the positive mass is repelled by the negative mass. Thus, the two masses will experience equal forces and accelerations in the same direction (in violation of Newton's third law) and the system of two particles will accelerate, seemingly without limit. The negative mass will chase the positive mass with constant acceleration.” In either scenario, shiz is gettin’ weird. If you’re being pedantic, negative mass would be impossible, because no mass equals no matter at all; but pedantry aside, what negative mass seems to mean is matter out of the constraints of one of the bonds of the universe. It makes sense that something like this would excite science journalists, I just hope we are positive next time. Okay, i’ll stop. The more we understand about particle physics, the better we're gonna understand the universe itself.