Sunday Science: Negative Matter

Image courtesy of the Science Photo Library.

This week, "negative mass" hit the headlines. It's got a lot of scientists jolly excited - and I've received a lot of messages asking me to explain what negative mass is.

Here we go.

Let's start with Newton's second law of motion. Newton's second law can be summed up using the following equation: F = ma, where 'F' is the force (that you shove the object with), 'm' is the mass of the object and 'a' is the acceleration it moves with.

In other words, if you push an object, it will accelerate in the direction you pushed it.

That's common sense, right?

With negative mass, the opposite happens.

You push an object and it accelerates towards you.

​That's pretty weird, right?

Well, maybe not. An electrical charge can be positive or negative.

So, why can't a mass be positive or negative?

Mr Freeze tries to throw his "negative matter" helmet but it's like it hits an invisible wall and goes in the opposite direction.

​Why can't you have -2 kg?

You can. Negative mass has cropped up in many other scientific theories, including those attempting to prove the existence of wormholes.

But no fundamental particles with negative mass have ever been discovered. This means we have no experimental insights into how a particle with negative mass would behave.

"What's a first here is the exquisite control we have over the nature of this negative mass, without any other complications," said co-author of this week's paper on negative mass Michael Forbes, assistant professor of physics at Washington State University.

That's why this latest breakthrough where a negative effective mass has been detected is so important - it gives us a way to understand negative mass and the theories that surround it. 

It could give us further insights into cosmological phenomena including neutron stars, dark matter, dark energy and black holes.

Extra reading

Despite the excitement surrounding this week's announcement, scientists have NOT actually created negative mass. They've created a negative effective mass. That one word makes the world of difference - you can find out more here.

And if you want to read the full scientific paper describing the phenomenon, click here.

What is Sunday Science?

Hello. I’m the freelance writer who gets tech. I have two degrees in Physics and, during my studies, I became increasingly frustrated with the complicated language used to describe some outstanding scientific principles. Language should aid our understanding — in science, it often feels like a barrier.
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So, I want to explain these science sayings and this blog series “Sunday Science” gives a quick, no-nonsense definition of the complex-sounding scientific terms you often hear, but may not completely understand. 

If there’s a scientific term or topic you’d like me to tackle in my next post, fire an email to [email protected] or leave a comment below. If you want to sign up to our weekly newsletter, click here.