Bad reporting or am I missing something here?

[Washington]

On Yahoo news there's an article titled, "Scientists Drop Theory of Everything Down Elevator Shaft" that deals with an experiment to find a T0E. Here's the relevant snippet.

"A new experiment offers hope by probing the very boundary between these two realms [quantum and classical physics], the researchers said. They experimented with a special type of super-cold matter called a Bose-Einstein condensate.

"Bose-Einstein condensates exist on the border between quantum and classical physics; they are governed by the laws of QM [quantum mechanics] but can take macroscopic dimensions," wrote the team, led by Tim van Zoest of the University of Hannover, in a paper published in the June 17 issue of the journal Science.

The Bose-Einstein condensate in the experiment was composed of a cloud of millions of rubidium atoms that were cooled to temperatures nearing absolute zero. At this point, they basically lose their individual identities and can be described by a single macroscopic wave function - essentially an equation from quantum mechanics, but on a large scale.

The researchers then dropped a capsule containing the Bose-Einstein condensate down a very tall tower built especially for scientific experiments. The drop allowed the material to experience weightlessness during its brief freefall.

The lack of gravity caused the gas to expand, and allowed the scientists to study the gravitational effects on the quantum gas.

The experiment showed that such projects could offer a fertile ground for testing the murky boundary between quantum mechanics and general relativity, the researchers said. They hope to one day send such an experiment to space, perhaps on the International Space Station.

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My question is, why, just because an object is in free fall, would gravity cease to exist? "The lack of gravity caused the gas to expand." I'm ready to conclude that the article's writer misspoke or doesn't understand what was going on.

What do you think?

 

[shinbits]

it's not that gravity doesn't exist, it's that the apparent effect of gravity is suspended. An object falling at the same speed would appear weightless to the person falling. If the falling person tried to hold that object during freefall, that object would have no weight because there's nothing to counteract gravity at that moment.

Basically, gravity is felt when there's something to counteract gravity, like when we stand on a solid floor. Without something to counteract gravity, that object is has something akin to weightlessness (though nothing really is weightless.)

 

[Washington]

it's not that gravity doesn't exist, it's that the apparent effect of gravity is suspended. An object falling at the same speed would appear weightless to the person falling.

But a falling object doesn't maintain a speed. It's continually accelerating, until it reaches its terminal velocity, if any.

If the falling person tried to hold that object during freefall, that object would have no weight because there's nothing to counteract gravity at that moment.

But it's mass would remain the same. And weight is simply the force exerted by gravity, and would still exist even if it could not be measured at a particular moment.

In any case, whether accelerating or maintaining a constant velocity, gravity would still be at work.

 

[keith99]

It is poor reporting. Likely by someone who can't even do the equations for the simplest of classic problems.

 

[Maxwell511]

The article is completely correct. It was implied by the previous sentence but maybe to stop all confusion the article should have said;

The lack of gravity, within its own reference frame, caused the gas to expand, and allowed the scientists to study the gravitational effects on the quantum gas.

I'll leave it to wikipedia to explain. It just has to do with subtleties relating the Einstein's Equivalence Principle.

 

[Maxwell511]

My question is, why, just because an object is in free fall, would gravity cease to exist?

A body in free fall motion is moving in a inertial reference frame as per the Equivalence Principle of General Relativity. Bodies on the earth are in a non-inertial reference frame. This means that within general relativity it is "more correct" to say that the experiment is not accerelating when it is in free fall and it is actually the earth that is accelerating. Due to this acceleration objects on the earth experience a "force" we call gravity. Take an object out of the non-inertial reference frame by dropping it, you take away the cause of the "force" of gravity.

"The lack of gravity caused the gas to expand." I'm ready to conclude that the article's writer misspoke or doesn't understand what was going on.

The writer is completely correct.

 

[shinbits]

But a falling object doesn't maintain a speed. It's continually accelerating, until it reaches its terminal velocity, if any.

That goes without saying. By the "same speed", I meant falling at the same rate, which can change, depending on how air is slowing down the falling object.

But it's mass would remain the same. And weight is simply the force exerted by gravity, and would still exist even if it could not be measured at a particular moment.

That's why I italicized "apparent". It's weightlessness in this case is relative, like with objects sent to outer space.

In any case, whether accelerating or maintaining a constant velocity, gravity would still be at work.

Yes, which is why I made sure to Italicize the word "apparent", because there's weightlessness relative to the falling object, like in the example I gave of trying to hold something while falling.

Doesn't matter, it may just be this article wasn't well reported.

 

[Washington]

The article is completely correct. It was implied by the previous sentence but maybe to stop all confusion the article should have said;

The lack of gravity, within its own reference frame, caused the gas to expand, and allowed the scientists to study the gravitational effects on the quantum gas.

I'll leave it to wikipedia to explain. It just has to do with subtleties relating the Einstein's Equivalence Principle.

Hey, Thanks for the link. It explains it very well.