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Mind Boggling!

Entry 546, on 2007-06-02 at 21:07:37 (Rating 1, Science)

One of the things I used to like to do when I was an astronomy educator was quote mind boggling facts to my audience. Of course, astronomy is probably the best science for amazing facts and big numbers because it involves the study of the whole Universe.

The reason I'm blogging about this is a fact quoted in a podcast I listened to today (I don't know how I would think of new blog subjects without podcasts). The podcast was an interview with a radio astronomer, and to illustrate how weak radio signals from space really are he quoted the following fact. The first radio astronomy was done by Karl Jansky in the 1930s. Since then the total power collected by every radio telescope in the world is less than the energy of one rain drop hitting the ground. Isn't that incredible? The energy collected in millions of hours of observations of the hundreds of radio telescopes in the world is less than that one rain drop. Cool!

I added that fact to my file of "amazing astronomy facts" and noticed some others. For example, the area of sky viewed by the Hubble Deep Field camera is the size of a single dot on your screen at normal viewing distance. In that area the HST can see 3000 galaxies! Imagine how many dots it would take to cover the sky, and how many galaxies there are in total if each dot contains 3000! Don't forget that galaxies typically contain 10 billion to 10 trillion stars, giving a total of about 100 billion trillion stars in the observable Universe.

These numbers really are astronomical! The strength of radio signals from space is astronomically small, and the size of the Universe is astronomically big. As I said, astronomy really does involve some mind boggling numbers.

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