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If you travel beyond the glare of city lights and take a few minutes to examine the nighttime sky, you might be able to detect the faint outline of our galaxy – what we call the Milky Way. Well, scientists believe there is a hidden component to The Milky Way and all galaxies in the universe — a spherical “halo” which could contain large amounts of invisible or “dark matter.” I’m Jim Metzner and this is the Pulse of the Planet.
“It looks like, from the best measurements we have today, something like 95 to 99 percent of the matter in the universe is this dark matter.”
Ben Oppenheimer is the Hubble Post Doctoral Research Fellow at the University of California in Berkeley.
“If you believe that Newton and Einstein were correct in their formulations of theory of gravity, then there has to be this other matter in order to explain the motions of the stars in our galaxy. They simply move too fast the rotation of the disk.”
In other words, in order for our enormous disk shaped galaxy to be moving at the speed it does, there must be – according to the laws of physics – more matter in the galaxy, and in the rest of the universe, than we can readily see.
“For example, at the location of the sun halfway out along this disk, is simply too fast to be due simply to the amount of matter that is in the stars that we can see. So it’s an indirect inference, basically, from what we can see, of what we can measure in the motions of objects.”
We’ll hear about what the invisible, or dark matter might be in future programs.
Pulse of the Planet is presented by the National Science Foundation. I’m Jim Metzner.
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