I just read an interesting article in the Sunday Mail's Review and decided to do a little search on it over the Internet. Michael Brooks (a consultant at New Scientist) is having his book '13 Things That Don't Make Sense' published this February. The first of those things is (both can be found here):
NASA scientists found evidence for life on Mars. Then they changed their minds
On July 20, 1976, the Viking landers scooped up some Martian soil and mixed it with radioactive nutrients. The mission's scientists all agreed that if radioactive methane was released from the soil, something must be eating the nutrients – and there must be life on Mars. The experiment gave a positive result, but NASA denied an official detection of Martian life. Today, there is even more evidence that something is creating methane on Mars. Is it life? The Viking experiment suggests it was. Martin Rees, England’s astronomer royal, calls the search for extraterrestrial life the most important scientific endeavour of our time. But have we already found it?
Apparently, the reason they changed their minds was due to readings from another instrument on the Viking mission that searched for traces of carbon in the Martian soil and found none. The verdict about life remains unchanged despite it being known that the second instrument couldn't even detect large quantities of carbon here on Earth. It was a dud, but as we are learning every day now, scientists protecting their backsides quickly lose any acquaintance with the truth.
The next 'thing' was this:
Has ET already been in touch?
It was an electromagnetic pulse that came from the direction of the Sagittarius constellation. It lasted 37 seconds and had exactly the characteristics predicted for an alien signal. Maybe that’s why, on 15 August 1977 it caused astronomer Jerry Ehman to scrawl "Wow!" on the printout from Big Ear, Ohio State University's radio telescope in Delaware. The nearest star in that direction is 220 light years away. If that really is where is came from, it would have had to be a pretty powerful astronomical event - or an advanced alien civilisation using an astonishingly large and powerful transmitter. More than 30 years later, its origin remains a mystery.
After much consideration, wondering what method aliens would use to attract attention, researchers decided that a radio signal at precisely 1,420 MHz - the vibration frequency of hydrogen, the most common molecule in the universe - would be the best choice. That's precisely what they got. It also came from an area of space completely devoid of stars, maybe from a spaceship?
What do you think about this? The easiest thing to do is err on the side of doubt. I mean, lakes of methane on Titan aren't immediately pointed at as evidence of life there. And frankly, that signal could have come from Earth and been bounced back by some phenomena much more likely than a passing alien spaceship.