Why We are Alone in the Galaxy | Marc Defant | TEDxUSF

Not to mention the tilt in the axis, the Goldilocks zone location, the amount of water on the planet, and the electromagnetic field emanating from our rotation and magma core, etc, etc, etc. Life is extremely rare, and sentient life extraordinarily more rare, and our favorite pastime is killing and harming one another. This is dead solid perfect in his vision.

He left out many other statistical oddities, the two most relevant to me are: it turns out that our star, the sun, is not your average star, but an extraordinary calm G-type star in a Galaxy otherwise full of unsteady red-dwarf stars that probably won‘t allow for habitable conditions on their surrounding tidally locked eye-ball planets. It turns out that by sheer luck we happen to effectively live on a „double-planet“ system, where a extraordinarily large moon has not only slowed down the rotations speed of our planet, but also stabilized the rotation axis, has helped very much in creating not only a stable environment, but that tidal changes of ocean levels caused by the moon may have triggered life in the first place (and maybe is the cause we have plate tectonics and volcanism, which helped to renew our athmosphere and our crust).

We need to find intelligent life on this planet before we look for it elsewhere. 😊

I often think about how life on earth is closer to its absolute end than its beginning, and the same goes double for multicellular life. If this is a golden planet and something like a human only emerges in a brief interval by the rarest of chances then yes, it's hardly ever going to happen.

Tedx: Where the greatest minds in the land give presentations in front of people who don't know how to record audio.

It happened at least once, given the immensity of our galaxy over the immensity of 13.4 billion years, it's statistically incomprehensible it hasn't happened thousands upon thousands of times.

Finally, finally. The voice of reason. ALL of the evidence points to life on only ONE planet, this one. Life elsewhere is pure conjecture. The history of earth and the history of life that we know make it extremely unlikely that it could have happened anywhere else.

"The sweeping claims and assertions made in this talk are based on the speaker’s own theory and lack legitimate scientific support." Lack of scientific support? Who flagged this talk? This guy makes perfect sense and he stated only a few of the hundreds of random events that had to take place in a particular place at a particular time in order for us to exist. Another example is the collision of the Indian land mass and Asia, which formed the Himalayas. This mountain range absorbed much of the atmosphere's CO2 which cooled the planet and creating just the right amount of ice and temperature to support the current 7 billion population. There are many more random events that were necessary for intelligent life to exist.

I absolutely hate when someone thinks that life can only happen the way it happens on earth...I understand that it's all we know but why limit the possibilities of a universe that seemingly is infinite.

Wow .This guy is amazing .To prove how intelligent life is rare just look at the comments section.

I heard Neil DeGrasse Tyson once said that people who ask why haven't we found other life in the universe was like someone filling a glass with ocean water and asking where are all the whales? The universe is a huge vast open space filled with billions of galaxies that outnumber all the grains of sand in all the world's beaches. We can only see a small portion of the universe from earth.

highly unlikely != impossible like the speaker said, a lot of unlikely events had to happen for us to be here, yet we're here, and if it can happen once then it can happen again else where in another time. The known universe is billions of years old and it's A LOT larger than what we see, that improves the odds for intelligent life. thank you for coming to my ted talk

In my humble opinion, time and distance are the biggest reasons why we haven't contacted INTELLIGENT life yet. There may have been countless life forms who evolved to something like bronze age, but were wiped out by extinction events over billions of light years of time and space.

“Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.” Calvin and Hobbes

One thing is for certain. Either we are alone or we are not alone. I think it would be far more extraordinary if we were alone.

Assume generously for a moment that every star in the observable universe has 1 habitable planet. That leads to roughly 10^25 habitable planets in the observable universe. I did a calculation sometime back that led me the conclusion that the probability of intelligent life arising on a habitable planet (abiogenesis + intelligence) was 10^-55, which is less than the number of habitable planets by order of 10^30. This pretty much means that Humans are the only intelligent life not only in the observable universe but possibly also in the un-observable universe twice it's size.

I think what he means at the end is that intelligent life is super rare, not regular forms of life...

Perhaps the point of the talk was to acknowledge the truly awe inspiring set of events (of which he only mentioned three) that improbably resulted in each of us and to urge each of us to simply appreciate how precious each individual life is. One does not, and Marc does not, invoke creationism to ponder and grasp, with enthusiasm, the profound significance of just some of the events that led to us any more than Carl Sagan did in his observations and writings. Suggest some of these folks get their noses out of the air.

Ted talks generally leave me cold. Most speakers can't reach, grab and hold my attention. Or beat out and lead me along a well defined train of thought. And I AM scatterbrained! So the fact that he did all of the above superbly is no mean feat.

Plus: An exceptionally stable sun; stable, nearly circular orbits for all major planets; two large gas giants far from the sun so they attract comets and meteors; a collision with a Mars-sized planet that yielded our moon which stabilized our earth’s rotation; the collision also liquified iron so that the liquid iron would sink and form a core that gives us our magnetic field that protects our atmosphere; the presence of phosphorus, a relatively rare element in most of the universe. There are more, but if each of these constitutes a fortunate outcome, the sum of these improbable events must extraordinarily improbable.