Question

Is there a way to create artificial zero-gravity? If not, how can we investigate (on Earth) the effects of zero-gravity on plants?

Unfortunately, it is not possible to create artificial zero-gravity on Earth. While we can simulate some of the effects of zero-gravity, we can never rid an Earth-bound experiment of the fundamental gravitational force. One of the methods scientists use to “counter” the effect of gravity on plants involves an apparatus known as a clinostat. A clinostat is like a small turntable set on its side, so that the plants attached are rotated in the vertical plane. It is usually operated very slowly, so that the clinostat imparts as little centripetal force to the test subjects as possible. This turning “confuses” the plant with respect to the DIRECTION of the gravity vector, but does not eliminate the force of gravity itself. Only by launching objects into near space, where the force of gravity is substantially reduced by the increased distance between the Earth and the object, can we truly study gravity as a scientific variable.

For more information on the effects of zero-gravity on plants, check out the Plant Gravitropism Database at http://biocomp.arc.nasa.gov/plants/.index.html
February 22, 2002