It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Thank you.
Some features of ATS will be disabled while you continue to use an ad-blocker.
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.
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.
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:
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 figured maybe it was electrostatic
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?
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.
Originally posted by 727Sky
So just because they found blackbody attraction does not mean there are not other forces at work...
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.
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
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 %.