Dimensions and Mass ```Name: Devdatta H. Status: other Age: 20s Location: N/A Country: N/A Date: 2000-2001 ``` Question: Can a thing which has only 2 dimensions have mass? Can we see it? What about the things which have more than 3 dimensions? Replies: Devdatta, The first thing comes to mind with a two-dimensional object is it cannot have any atoms. Atoms are three-dimensional objects. Of course, there is no law that all things must be made of atoms. There is no law that only three-dimensional objects have mass. Quantum physicists have invented models for theoretical two-dimensional objects, but I do not know of any that have ever been really detected. As for "seeing" such an object, I do not know how it could interact with anything passing through it. Energy transfer usually requires some distance over which it can occur. A 2-D object would need light traveling along its surface for our eyes to notice it. As for more than three dimensions, such objects do exist, and you are one of them. The only difference is that our senses don't deal with the fourth dimension in the same way as the first three. Our senses notice the fourth dimension as passage of time. We can think of ourselves now, or two days ago. We can think of ourselves as here, or three feet back. Therwe really isn't a huge amount of difference. Einstein was the first to notice that in many ways passage of time behaves a great deal like passage of distance. He joined them together into a four-dimensional "space-time". Dr. Ken Mellendorf This Is Only My Guess: There is no real, physical, 2-D object. One can imagine that if it were to exist, it would carry no mass. 4-D objects do not (as far as I know) exist either. However, I've met people who claimed to be able to visualize 4-D objects. The University of Illinois in Urbana-Champaign has a room called The Cave. In there, images are projected onto all the walls, allowing participants to see objects in 3-D. With this room, many professors have been able to use Time to see the 4th dimension. Note, I said USE Time; Time is NOT the 4th dimension that many of us believe. I was given a short lecture on how this actually works. If you are curious, I can send you a more detailed letter explaining the concept behind this rather amazing visualization experiment. -Wil Lam Devdatta - The subject of dimensions has fascinated mankind for centuries. For some there is an answer to your question - an answer assuming the limits of our three dimensional world. For others the answer resists the limits of our 3D world. For the first group... 2D objects do not exist in reality, only as illusions such as a motion picture image on a screen. This group would answer your first question, "No, 2D objects have no mass." This group would also consider the 4th dimension an illusion with the possible exception of time. Height, width, depth (that's three) and how long it has been there (the 4th). Other suggest, but have a hard time proving the existence of object that exist with a different number of dimensions. Perhaps mass is only a property of 3D objects and objects with varying numbers of dimensions possess other properties. You might find interesting reading in "Flatland" (sorry, don't recall the author) that is the story of 2d beings. Or, try reading (a much tougher read) "Hyperspace" by Kaku who suggests the ultimate existence of 10 dimensions. Think on! Larry Krengel Click here to return to the Physics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs