Hailing Frequencies Ope1

Hailing Frequencies Ope1 - Hailing Frequencies Open Captain...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Hailing Frequencies Open, Captain The section title is a bit misleading---astronomers are only trying to eavesdrop on conversations already going on. Astronomers are searching for messages carried via electromagnetic radiation (light) because it is the speediest way to send a message. It travels at about 300,000 kilometers/second or about 9.5 trillion kilometers per year (remember that this is equal to one light year?). In particular, the radio band part of the electromagnetic radiation spectrum is searched for messages because radio can get through all of the intervening gas and dust easily. Radio also does not require that much energy to produce it so it should be easier for extraterrestrials to make. The lowest interference from background natural sources is between frequencies of 1 to 20 gigahertz. Our atmosphere narrows this range to 1 to 9 gigahertz. The optimum range is 1 to 2 gigahertz. This is also where the 21-cm line of neutral atomic hydrogen and the slightly smaller wavelength lines of the hydroxide molecule (
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 2

Hailing Frequencies Ope1 - Hailing Frequencies Open Captain...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online