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Academic Minute

Dr. Ed Stander, SUNY Cobleskill - Scale and Astronomy


Albany, NY – In today's Academic Minute, Dr. Ed Stander of SUNY Cobleskill explains why astronomers must consider scale when applying the laws of physics to any object beyond Earth.

Ed Stander is a professor of geology, astronomy, and environmental sciences at SUNY Cobleskill. He holds a Ph.D. from Universite Laval Civil Engineering, Quebec.

About Dr. Stander

Dr. Ed Stander, SUNY Cobleskill - Scale and Astronomy

What works on the human scale doesn't necessarily hold true on larger scales. Newton's laws, for example, work fine if one wants to know the energy needed to drive from New York to Boston, but they don't work so well when one tries to predict the motion of planets around the sun.

For example, many scientists in the late 1800's believed that Mercury's erratic behavior through space was due to a nearby companion planet they called Vulcan. It was only through Einstein's work at the turn of the century that we realized that scale was actually the culprit, and that Newton's laws simply don't apply to objects as massive as the Sun.

Today, astronomers deal with distances on the order of the entire universe - and one has to wonder if Einstein's theories still work on such enormous scales.

For example, we now have evidence that, contrary to all expectations, the universe expanded rapidly at first, then slowed down, and is now expanding rapidly again. How is this possible? While most astronomers today would argue that an unknown quantity called dark energy is responsible for the present acceleration, it's also possible that astronomers are simply up against another scale effect.

It's possible, for example, that the speed of light is a firm value on human terms, but was not entirely constant over the lifetime of the universe. Perhaps, in fact, the acceleration we are now experiencing is simply caused by a slight decrease in the speed of light over time. We don't presently have the precision to measure such minute changes in light speed here on Earth.

That's the nature of science. However someday we might, and it is through such questions that new techniques are developed. Does dark energy really exist, or is Universal acceleration simply another scale effect? Well, only space-time will tell.

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