Now for something totally weird...Blackbody attraction stronger than gravity!

phys.org...

Perfectly non-reflective objects, called blackbodies, produce blackbody radiation when at a uniform temperature. Although the properties of blackbody radiation depend on the blackbody's temperature, this radiation has always been thought to have a net repulsive effect. Now in a new study, scientists have theoretically shown that blackbody radiation induces a second force on nearby atoms and molecules that is usually attractive and, quite surprisingly, even stronger than the repulsive radiation pressure. Consequently, the atoms and molecules are pulled toward the blackbody surface by a net attractive force that can be even stronger than gravity. The new attractive force—which the scientists call the "blackbody force"—suggests that a variety of astrophysical scenarios should be revisited.

Notice not colder but warmer for the greater effect

The underlying basis of the new force has actually been known for at least half a century: blackbody radiation shifts the atomic energy levels of nearby atoms and molecules. In these "Stark shifts," the ground state of the atom or molecule is shifted to a lower energy by an amount that is roughly proportional to the fourth power of the blackbody's temperature. That is, the hotter the blackbody, the larger the shift.

The discovery that blackbody radiation can impart an overall attractive force on nearby objects could have great significance for many astrophysical scenarios, in particular the interaction between interstellar gas and dust grains. The findings could also have applications in experimental set-ups, such as the effects of hot microstructured surfaces in vacuum chambers. However, the scientists note that the attractive blackbody force will be difficult to measure in the lab because it will be very weak under typical laboratory conditions.

This finding will help theories on the formation of many structures we see in the universe..Just adds one more snap shot to the workings of matter. So over coffee if someone mentions blackbody radiation you will know what they are talking about....

I find black bodies just as attractive as any other sort.

reply to post by Phage


Hahahahaha I knew that was coming and as you, I find beauty where ever, when ever, and appreciate all beautiful parts and wholes of creation !! hahahah

Er.. how can anything be perfectly non reflective?

What type of thing is a blackbody? The wikipedia article doesn't help. en.wikipedia.org...

Is it an earthly object, an object in space that has been observed or what?

What are these objects made of?

Originally posted by 727Sky
This finding will help theories on the formation of many structures we see in the universe..Just adds one more snap shot to the workings of matter. So over coffee if someone mentions blackbody radiation you will know what they are talking about....

I have no idea if this is related or unrelated, but it's a video in space of small particles clumping together, and I always thought gravity was too weak to do what's shown here so thought it might be a stronger force than gravity involved:


I figured maybe it was electrostatic perhaps but after hearing about this now I wonder if it could be a factor.

They say this "force" might be difficult to measure in a laboratory, but if it's stronger than gravity and they can measure gravitational force in the lab, it seems like it should be possible to measure it, right?

reply to post by Arbitrageur

I figured maybe it was electrostatic

I did too. The electrostatic process was always used to explain water droplets on a tabletop joining through the cohesion factor that applies to water. Anytime you have water and it touches more water they attract each other to form a bigger droplet. When water condenses in the clouds they collide with other water molecules which combine and form water droplets. The longer the droplets stay in the air the bigger they get. As the water droplets move higher in the air there is a chance that they will freeze and become a small ball of ice that we call hail. If it freezes before it condenses to a droplet it becomes snow. If it forms into droplets and then freezes it becomes sleet. etc etc..So just because they found blackbody attraction does not mean there are not other forces at work...

People like simple answers that cover everything when in reality there are usually multiple easy answers that form an answer for a complex problem/system. Anyway back in the dark days of schooling when we had to add, subtract and read in science class that is what I remember or something like that...

Originally posted by JohnPhoenix

What type of thing is a blackbody? The wikipedia article doesn't help. en.wikipedia.org...

Is it an earthly object, an object in space that has been observed or what?

Blackbody radiation... It's Shadow People!!! en.wikipedia.org...
Now the paranormal world has another scientific explanation for shadowy figures and books flying off shelves or that dark mass floating above your bed choking you.

reply to post by 727Sky

It makes sense to me, that if something is repelled by the blackbody force, then other things will necessarily be sucked in to fill the void. I can visualize it, even if I can't verify it scientifically.

Originally posted by 727Sky
So just because they found blackbody attraction does not mean there are not other forces at work...

Right. In the case of the astronaut video showing salt or sugar particles clumping, the video doesn't really state the cause, but they imply it's gravity the way they jump right from that into talking about when the clumps get bigger there's gravitational attraction, which there is, but I'm not sure that's what starts the clumps forming.

However in the case of the OP article claim, they didn't find anything experimentally, and in fact suggested it would be hard to measure, so their theoretical calculations are only related to the effect relates to blackbody radiation. If they have such difficulty making measurements one wonders how they will go about verifying their theoretical claims.

reply to post by JohnPhoenix

The concept of the black body is an idealization, as perfect black bodies do not exist in nature. Graphite and lamp black, with emissivities greater than 0.95, however, are good approximations to a black material. Experimentally, black-body radiation may be established best as the ultimately stable steady state equilibrium radiation in a cavity in a rigid body, at a uniform temperature, that is entirely opaque and is only partly reflective. A closed box of graphite walls at a constant temperature with a small hole on one side produces a good approximation to ideal black-body radiation emanating from the opening.

From Black-body radiation @ Wikipedia

Originally posted by Panic2k11
reply to post by JohnPhoenix

 

The concept of the black body is an idealization, as perfect black bodies do not exist in nature. Graphite and lamp black, with emissivities greater than 0.95, however, are good approximations to a black material. Experimentally, black-body radiation may be established best as the ultimately stable steady state equilibrium radiation in a cavity in a rigid body, at a uniform temperature, that is entirely opaque and is only partly reflective. A closed box of graphite walls at a constant temperature with a small hole on one side produces a good approximation to ideal black-body radiation emanating from the opening.

From Black-body radiation @ Wikipedia

So this Blackbody thing is just a theory and they themselves do not really exist. They get close with the materials Graphite and lamp black but not 100 %.

I wonder.. why black at all? Could this not be properties of Graphite and lamp black? Why don't they do this experiment with other substances with varying colors? - what is it about Graphite and lamp black that give off these properties - the ability to be non reflective ( or at least mostly non reflective)?

All this sounds to me like they are reaching - like the bogus dark matter theories they MADE UP to account for observations science cannot understand.

Edit to say Thanks for the answer to my above question.

So this is after they flood a black body with radiation, or just all black bodies naturally warp the space around them to attract matter?

reply to post by JohnPhoenix


Did you read the articles ?

The black has to do with the reflective property of a body a black body (like a black hole that is also talked on the wikipedia article I linked) it is fully explained there, and no it is not simply theoretical even if a perfect black body can't be created.

The one thing I find hard to understand is that it has anything at all to do with gravity, it seems that the attraction is electromagnetic in nature...

PS:It has nothing to do with dark matter or even dark energy (that also amongst themselves are very distinct, dark in that topic only means "not directly observable").

(Can it be leveraged to generate artificial "gravity", pull ? That was what drove my curiosity...)

Originally posted by JohnPhoenix

So this Blackbody thing is just a theory and they themselves do not really exist. They get close with the materials Graphite and lamp black but not 100 %.

Here, this two and a half minute intro
may help a bit.


Mike

I'm no physicist, but I'd be willing to bet that the phenomena also has a proportional relationship between energy density and surface area and that Susskind and Hawing already covered some of the math involved to describe what's going on.

And it may not exactly be stronger than gravity... Odds are it has the effect has the same inverse square falloff... Thus it is gravity. (Considering that the underlying mechanism for gravity is from the energy which mass represents rather than any other unknown property.) Just that it's occuring via a mechanism that's currently not well understood, and you can pump in more energy from external sources quickly than by physically adding mass in a more conventional manner. Considering that one way energy may be expressed is as heat, and this black body radiation phenomena may make more sense. Then you have the radiated heat transfering to other objects which increases their energy level... It's that part of it which would seem to make gravity caused by this phenomena stronger than gravity produced by more normally understood conventions directly relating to mass.

Of course me being a random person on the internet, you can take it or leave it when it comes to my speculation about what may be occuring.