Extraterrestrial life is defined as life that does not originate from Earth. Referred to as alien life, or simply aliens (or space aliens, to differentiate from other definitions of alien or aliens) these hypothetical forms of life range from simple bacteria-like organisms to beings far more complex than humans.
We are not alone in the universe -- and alien life forms may have a lot more in common with life on Earth than we had previously thought.
That's the stunning conclusion one NASA scientist has come to, releasing his groundbreaking revelations in a new study in the March edition of the Journal of Cosmology.
In what's sure to rekindle the debate over the question of life beyond Earth, a scientist at NASA's Marshall Space Flight Center says he has fossil evidence of bacterial life inside of a rare class of meteorites .
Writing in the March edition of the Journal of Cosmology, Richard B. Hoover argues that an examination of a collection of 9 meteorites - called CI1 carbonaceous meteorites - contain "indigenous fossils" of bacterial life.
While Tussel and others are thoroughly convinced, psychologists say the media-generated images of alien kidnappings can become easily engrained in our subconscious and then vividly re-enacted in our dreams.
“Maybe life was seeded on earth -- it developed on comets for example, and just landed here when these things were hitting the very early Earth,” Shostak speculated. “It would suggest, well, life didn’t really begin on the Earth, it began as the solar system was forming.”
Raul-Julia claims there is proof that the Mayans had intended to lead the planet for thousands of years, but were forced to escape after an invasion by "men of dark intentions," leaving behind evidence of an advanced race.
"The Mexican government is not making this statement on their own -- everything we say, we're going to back it up," he said.
In reality, he said, compared to previous positions with frequent missions, "Area 51 was the most boring place I ever worked."
No aliens, no spacecraft from far-flung planets, no underground passageways, he said.
A California armchair astronomer claims a white, fuzzy image on the red planet's surface might be evidence of life -- and even NASA didn't immediately know what if anything he had found.
"Many scientists and mathematicians have looked... at the question of whether life likely exists beyond Earth, and have come to the conclusion that the odds are pretty high that somewhere among the trillions and trillions of stars in the Universe there is a planet other than ours that is home to life," he wrote.
"Many have also noted, however, that the odds of us making contact with any of them - especially any intelligent ones - are extremely small, given the distances involved."
A special mission to the Red Planet has revealed the likely presence of a form of pond scum — the building blocks of life as we know it.
NASA unveiled the results of the recent Opportunity and Spirit probes sent millions of miles through the solar system to discover signs of extraterrestrial life.
"The U.S. government has no evidence that any life exists outside our planet, or that an extraterrestrial presence has contacted or engaged any member of the human race," writes an Obama administration official on the White House website.
In fact, the researchers conclude, the current knowledge about life on other planets suggests that it's very possible that Earth is a cosmic aberration where life took shape unusually fast. If so, then the chances of the average terrestrial planet hosting life would be low.
"Fossil evidence suggests that life began very early in Earth's history and that has led people to determine that life might be quite common in the universe because it happened so quickly here, but the knowledge about life on Earth simply doesn't reveal much about the actual probability of life on other planets," Turner said.
Nearly half of all Americans and millions more globally believe we're not alone, according to a 2000 ABC poll. While 40 million Americans say they have seen or know someone who has seen an unidentified flying object, or UFO, a growing number believe they've actually met aliens.
Since the beginning of civilization, people have wondered if we are alone in the universe or whether there is intelligent life somewhere else. In the late twentieth century, scientists converged upon the basic idea of scanning the sky and "listening" for non-random patterns of electromagnetic emissions such as radio or television waves in order to detect another possible civilization somewhere else in the universe. In late 1959 and early 1960, the modern SETI era began when Frank Drake conducted the first such SETI search at approximately the same time that Giuseppe Cocconi and Philip Morrison published a key journal article suggesting this approach.
NASA joined in SETI efforts at a low-level in the late 1960s and early 1970s.