CR4® - The Engineer's Place for News and Discussion®


A place for deriving stuff. We take requests.

Physicists Create a Fluid With Negative Mass

Posted April 20, 2017 8:30 AM by Bayes

One of the interesting things you learn early on in physics is that there is nothing in physics that forbids negative mass values. There has long been debate whether or not this really meant objects with negative mass exist. Recently some scientists at Washington State University have demonstrated it's possible. Here is the article:

Physicists create 'negative mass'

Washington State University physicists have created a fluid with negative mass, which is exactly what it sounds like. Push it, and unlike every physical object in the world we know, it doesn't accelerate in the direction it was pushed. It accelerates backwards.

Hypothetically, matter can have negative mass in the same sense that an electric charge can be either negative or positive. People rarely think in these terms, and our everyday world sees only the positive aspects of Isaac Newton's Second Law of Motion, in which a force is equal to the mass of an object times its acceleration, or F=ma.In other words, if you push an object, it will accelerate in the direction you're pushing it. Mass will accelerate in the direction of the force.The phenomenon is rarely created in laboratory conditions and can be used to explore some of the more challenging concepts of the cosmos, said Michael Forbes, a WSU assistant professor of physics and astronomy and an affiliate assistant professor at the University of Washington. The research appears today in the journal Physical Review Letters, where it is featured as an "Editor's Suggestion."

"That's what most things that we're used to do," said Forbes, hinting at the bizarreness to come. "With negative mass, if you push something, it accelerates toward you."

Conditions for negative mass

He and his colleagues created the conditions for negative mass by cooling rubidium atoms to just a hair above absolute zero, creating what is known as a Bose-Einstein condensate. In this state, predicted by Satyendra Nath Bose and Albert Einstein, particles move extremely slowly and, following the principles of quantum mechanics, behave like waves. They also synchronize and move in unison as what is known as a superfluid, which flows without losing energy.

Led by Peter Engels, WSU professor of physics and astronomy, researchers on the sixth floor of Webster Hall created these conditions by using lasers to slow the particles, making them colder, and allowing hot, high energy particles to escape like steam, cooling the material further.

The lasers trapped the atoms as if they were in a bowl measuring less than a hundred microns across. At this point, the rubidium superfluid has regular mass. Breaking the bowl will allow the rubidium to rush out, expanding as the rubidium in the center pushes outward.

To create negative mass, the researchers applied a second set of lasers that kicked the atoms back and forth and changed the way they spin. Now when the rubidium rushes out fast enough, if behaves as if it has negative mass."Once you push, it accelerates backwards," said Forbes, who acted as a theorist analyzing the system. "It looks like the rubidium hits an invisible wall."

Avoiding underlying defects

The technique used by the WSU researchers avoids some of the underlying defects encountered in previous attempts to understand negative mass.

"What's a first here is the exquisite control we have over the nature of this negative mass, without any other complications" said Forbes. Their research clarifies, in terms of negative mass, similar behavior seen in other systems.This heightened control gives researchers a new tool to engineer experiments to study analogous physics in astrophysics, like neutron stars, and cosmological phenomena like black holes and dark energy, where experiments are impossible."It provides another environment to study a fundamental phenomenon that is very peculiar," Forbes said.

Read more at:

53 comments; last comment on 07/24/2017
View/add comments

NASA Announcement Today on Potential Habitats for Alien Life

Posted April 13, 2017 9:10 AM by Bayes

NASA Announcement Today at 2 p.m. EDT

NASA will discuss new results about ocean worlds in our solar system from the agency’s Cassini spacecraft and the Hubble Space Telescope during a news briefing 2 p.m. EDT on Thursday, April 13. The event, to be held at the James Webb Auditorium at NASA Headquarters in Washington, will include remote participation from experts across the country.

You can watch it here, on NASA TV


One of the potential habitats to be discussed will be Saturn's 6th largest moon, Enceladus. There appears to be evidence of hydrothermal activity, based on the amount of hydrogen in plumes emanating from the moon's south pole. The large amount of hydrogen is strongly suggestive of a constant hydrothermal process wherein the ocean under the surface of Enceladus is interacting with rock and organic compounds. The amount of hydrogen present is in disequilibrium i.e. if there was not a process that was constantly generating hydrogen the observed hydrogen levels would likely be lower than what is seen. Something is pumping it out.

To be clear, none of this indicates there is life in the oceans of Enceladus. Only that life supporting conditions might exist there. This is still significant since it further extends the possible habitable zones of the solar system and all star systems in general. It should be an interesting press conference.

1 comments; last comment on 04/17/2017
View/add comments

Earth-Sized Exoplanet's Atmosphere Detected

Posted April 07, 2017 9:04 AM by Bayes

I came across this article and thought I would pass it along. One of the next steps in the observations of exoplanets is to see if they have atmospheres and to, if possible, characterize those atmospheres. It's good to see that scientists are already making progress in this area!

Atmosphere containing water detected around rocky exoplanet

An Earth-sized planet orbiting a dim star 39 light years away has a hazy atmosphere that could indicate the presence of a “water world”. It is one of the first times astronomers have been able to detect an atmosphere surrounding a small rocky

planet. Similar observations using the next generation of powerful telescopes could be used to look for life outside the solar system.

Until now, scientists have mostly been able to spot the atmospheres of giant “hot Jupiter” exoplanets that are very unlikely to support life. The super-Earth planet GJ 1132b was observed as it passed in front of a cool red dwarf star, blocking out some of the star’s light. By measuring the slight drop in the star’s brightness, astronomers were able to work out that the planet was 1.4 times the size of Earth. They also found that in one light wavelength band, the planet looked slightly bigger. This could be explained by an atmosphere that was opaque to some light wavelengths, but transparent to others.

“While this is not the detection of life on another planet, it’s an important step in the right direction,” says John Southworth at the University of Keele, who led the team. The detection of an atmosphere around GJ 1132b marks the first time that an atmosphere has been detected around a planet less than twice the size of Earth. Previously, we had seen a waterless atmosphere around the planet 55 Cancri e, which is between 6 and 8 times Earth’s mass.

The Article Can Be Found Here

19 comments; last comment on 04/21/2017
View/add comments

A Big Day for Rocketry!

Posted March 30, 2017 11:10 AM by Bayes

SpaceX’s Falcon 9 rocket will deliver SES-10, a commercial communications satellite for SES, to a Geostationary Transfer Orbit (GTO). SES is a world-leading satellite operator, providing reliable and secure satellite communications solutions across the globe. The SES-10 mission will mark a historic milestone on the road to full and rapid reusability as the world’s first reflight of an orbital class rocket.

Falcon 9’s first stage for the SES-10 mission previously supported the successful CRS-8 mission in April 2016. SpaceX is targeting launch of SES-10 from historic Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center in Florida. The two and a half hour launch window opens on Thursday, March 30, at 6:27 p.m. EDT, or 10:27 p.m. UTC. The satellite will deploy approximately 32 minutes after launch. A backup launch window opens on Saturday, April 1, at 6:27 p.m. EDT, or 10:27 p.m. UTC.

Watch Live From Here:

6 comments; last comment on 03/31/2017
View/add comments

Anti-Aging Breakthrough

Posted March 27, 2017 8:48 AM by Bayes

I came across this article and thought it was interesting...

UNSW scientists unveil a giant leap for anti-aging

UNSW researchers have made a discovery that could lead to a revolutionary drug that actually reverses ageing, improves DNA repair and could even help NASA get its astronauts to Mars. In a paper published in Science today, the team identifies a

critical step in the molecular process that allows cells to repair damaged DNA. Their experiments in mice suggest a treatment is possible for DNA damage from ageing and radiation. It is so promising it has attracted the attention of NASA, which believes the treatment can help its Mars mission.

While our cells have an innate capability to repair DNA damage ? which happens every time we go out into the sun, for example - their ability to do this declines as we age. The scientists identified that the metabolite NAD+, which is naturally present in every cell of our body, has a key role as a regulator in protein-to-protein interactions that control DNA repair. Treating mice with a NAD+ precursor, or "booster," called NMN improved their cells' ability to repair DNA damage caused by radiation exposure or old age.

"The cells of the old mice were indistinguishable from the young mice, after just one week of treatment," said lead author Professor David Sinclair of UNSW School of Medical Sciences and Harvard Medical School Boston. Human trials of NMN therapy will begin within six months. "This is the closest we are to a safe and effective anti-ageing drug that's perhaps only three to five years away from being on the market if the trials go well," says Sinclair, who maintains a lab at UNSW in Sydney.

Article Continues Here

15 comments; last comment on 03/31/2017
View/add comments

Previous in Blog: Can Brain and Spine Implants Help Overcome Paralysis?  
Show all Blog Entries in this Blog