Physicists observe 'negative mass'

Physicists observe 'negative mass'

Physicists have created a fluid with "negative mass", which accelerates backwards when pushed.

In the everyday world, when an object is pushed, it accelerates in the same direction as the force applied to it; this relationship is described by Isaac Newton's Second Law of Motion.

But in theory, matter can have negative mass in the same sense that an electric charge can be positive or negative.

The phenomenon is described in Physical Review Letters journal.

Prof Peter Engels, from Washington State University (WSU), and colleagues cooled rubidium atoms to just above the temperature of absolute zero (close to -273C), creating what's known as a Bose-Einstein condensate.


In this state, particles move extremely slowly, and following behaviour predicted by quantum mechanics, acting like waves.

They also synchronise and move together in what's known as a superfluid, which flows without losing energy.

To create the conditions for negative mass, the researchers used lasers to trap the rubidium atoms and to kick them back and forth, changing the way they spin.

When the atoms were released from the laser trap, they expanded, with some displaying negative mass.

"With negative mass, if you push something, it accelerates toward you," said co-author Michael Forbes, assistant professor of physics at WSU.

He added: "It looks like the rubidium hits an invisible wall."

The technique could be used to better understand the phenomenon, say the researchers.

"What's a first here is the exquisite control we have over the nature of this negative mass, without any other complications," said Dr Forbes.

This heightened control also gives researchers a tool for exploring the relationship between negative mass and phenomena observed in the cosmos, such as neutron stars, black holes and dark energy.



Add Comment

all comments

  Other news

more
Texas revives transgender ‘bathroom bill’ for public schools

Texas revives transgender ‘bathroom bill’ for public schools..

22-May, 01:40

Protesters at an Austin news conference in January on a bathroom bill...

‘Brexit virus’: 1,000s of Britons getting hepatitis from EU-imported pork

‘Brexit virus’: 1,000s of Britons getting hepatitis from EU-imported pork..

22-May, 07:24

Tens of thousands of Britons are being infected with a potentially...

Sinkhole opens at Trump's Florida retreat

Sinkhole opens at Trump's Florida retreat..

22-May, 14:57

A sinkhole has opened at President Donald Trump's Mar-a-Lago golf resort...

Surf's up: Monstrous 64-foot wave measured in Southern Ocean

Surf's up: Monstrous 64-foot wave measured in Southern Ocean..

22-May, 14:48

An Australian frigate, the HMAS Warragunga, crashes through the waves in...

New immigration memos announce more than 15,000 new hires

New immigration memos announce more than 15,000 new hires..

21-Feb, 11:41

The Department of Homeland Security released two new memos this morning...

Gareth Edwards on what George Lucas thought of 'Rogue One'

Gareth Edwards on what George Lucas thought of 'Rogue One'..

14-Mar, 15:16

For the new generation of filmmakers taking up the "Star Wars" mantle...

Brazil Ex-First Lady No Longer Has Brain Function

Brazil Ex-First Lady No Longer Has Brain Function..

02-Feb, 08:26

Doctors and former President Luiz Inacio Lula da Silva say Brazil's...

Without immigrants, the US economy would be a 'disaster,' experts say

Without immigrants, the US economy would be a 'disaster,' experts say..

16-Feb, 18:56

Immigrants across the U.S. are refusing to go to work, attend school and...