The leading astronomy intellectuals tell the approximate probability of the existence of aliens to be 99%.
It makes you think that if aliens are so very likely to encounter, why haven’t we found any of those so very obvious extraterrestrial civilizations yet?
The active Search Extra Terrestrial Intelligence has been ongoing for half a century. To date, no extra terrestrial signals from stellar systems have ever been detected.
Here are popular theories on why our search has come up empty.
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1. The Rare Earth Hypothesis
Basically, we’re unique. The Rare Earth hypothesis argues that planets with complex life, like Earth, are extremely rare and that intelligent extraterrestrial life is highly improbable. Hence, we are one of a kind.
2. The Gaian Bottleneck
They didn’t survive. The Gaian Bottleneck hypothesis, by astrobiologist Dr. Aditya Chopra, suggests that alien beings are all dead – they simply didn’t make it. Life forms on “habitable” planet failed to emerge quickly enough to stabilize the planet and pave the way for more life.
3. The Great Filter
Earth was subjected to the Great Filter-five mass extinction events – but nevertheless evolved complex creatures. What if all “habitable” planets were hit with killer asteroids, scorched by solar flares, torn apart by geological upheavals, seared by supernova blasts or gamma ray burst radiation, and that of all worlds only Earth successfully hurdled the stumbling blocks?
4. The Great Silence
Alas, We’re not worth it. The Great Silence hypothesis posits that advanced beings who belong to a Type III civilization on the Kardashev Scale, able to harness the energy output of a whole galaxy, simply do not reach out to insignificant carbon-based humans. Why brother with Type O bipeds?
5. Early Birds
Earth had a head start. In a study, Dr. Peter Behroozi said that compared to all the planets that will ever from in the Universe, the Earth in actually quite early. The last star will burn out 100 trillions years from new and 92% of planets are yet to be born. We are the first – but not necessarily the last.
6. Not Life As We Know It
We’ve had it wrong all the time. ETs may not be biological being like us at all. Noted astronomer Lord Martin Rees said they might be machines – not organic creatures. So we should be looking for solar-harvesting, non carbon – based structures instead of listening for radio signals.
7. A Long Road Ahead Of US
Basically, we’ve got a long way to go, and a lot more searching to do. SETI has barely scratched the surface of the radio universe-there are many more wavelengths to scan, so we shouldn’t give up hope yet.
8. In Galaxy Far, Far Away
46.5 billion light – years is the distance to the edge of the observable universe (that’s really far!). We’ve scanned for ET signals to just around 40,000 light – years from Earth; we haven’t even out passed the bounds of our galaxy, which is 100,000 light – year wide. aliens intelligence could simply be too far away for our current technology to reach.