What was Herschel's theory about the structure of the universe?

On Thu, 4 Jun 1998, Chris wrote:

> What did the aboriginies think the univers's structure was like in the =
> past?

I'm not sure about this - I'll ask around and see if anybody knows. Most
"primitive" cultures believed that the Earth was the center of the
universe. But I can't give a more detailed answer yet. I'll let you know
if I learn more.

> What was herschel's theory about the structure of the universe?

Williams Herschel realized that the sun was a star, just like other
stars. So, he tried to get a picture of the galaxy by starcounts -
counting the number of stars he could see in each direction in the sky.
He assumed that, the more stars in a given part of the sky, the further
the galaxy went in that direction. His drawing showed a nearly-flat disk
of stars, with the sun toward the middle.

Herschel was right about the galaxy being like a disk, but he had the
sun's position wron. Herschel didn't realize that dust and gas in space
block the light from more distant stars, preventing us from seeing very
far. It took a couple of centuries before scientists realized this.

Herschel was ahead of his time. With his telescopes, he noticed that many
cloudy-looking objects were disk-shaped, leading him to guess that these
were distant systems of stars similar to our own galaxy. These "island
universes" had been hypothesized by Immanual Kant a few years earlier.
Unfortunately, very few people believed this idea until the 1920, when
astronomer Edwin Hubble, using the world's largest telescope, showed that
the Andromeda Nebula was actually made of stars, and was located over a
million light-years away.

Hope this helps!

Sincerely,

Kurtis Williams

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