In lighter, but nonetheless fascinating science news, SETI guru Frank Drake warns that aliens may soon be unable to detect us because we're using fewer and fewer technologies which allow radio waves to make it into space. Therefore, we may only be detectable by aliens for the incredibly short timeframe of about 100 years, a fraction of a blink in the history of the universe.
This may also go a long ways to explaining why we haven't heard from E.T. Advanced alien societies may have abandoned such technologies eons ago for inventions which limit the transmissions.
So, don't hope to find ALF via ancient alien transmissions of Fifth Rock from Alpha Centauri. Instead, we need to look for and send intentional beacons in order to detect our neighbors in the universe.