there needs to a civilization within reasonable range, since radio waves weaken exponentially (meaning that the further away a civilization is, the stronger^2 the signal needs to be)
the time that they emit radio must overlap with the amount of lightyears far away they are ago
the signal must not look like noise
we need to be listening in that direction and be explicitly looking for an alien signal
Nobody likes noisy neighbours.
If you want to contact me ring my doorbell. Don't blast Metallica loudly and expect me to understand that you ordered the songs to spell out 'can we borrow your lawnmower?'.
The universe is 13.7 billion years old.
Earth formed 4.5 billion years ago, and 1 billion years later the first life forms evolved.
The first Hominids evolved about 2 million years ago, modern Humans 300 thousand years ago. 12000 years ago we developed agriculture. Humans invented the radio in 1890, 132 years ago.
So humans have had the ability to transmit radio waves for 1% of the time we've had agriculture. Humans have had agricultural civilization for only 4% of our species existence. We as a aspecies have only existed for 0.086% of the time life has existed on earth. And life on earth itself has only been around for 26% of the universe's existance.
Even if we assume that life began at roughly the same point everywhere in the universe compared to earth( which is a huge assumption), that still leaves a huge margin for other civilizations on other planets to have evolved, progressed, and died out, long before we even evolved.
The odds that another planet developed sapient life which progressed to a technologically equivalent or superior level to humans at the same exact time that we did is incredibly unlikely, which I think is a far simpler explanation than the dark forest theory.
Edit: forgot to move the decimal over when converting to percentages lmao. Fixed now. Its still exceptionally unlikely, but the numbers I had were way off
that still leaves a huge margin for other civilizations on other planets to have evolved, progressed, and died out, long before we even evolved.
That's what Hawking argues, but his guess for why they're dying out is someone else nukes them when they detected.
The same math makes one wonder why aliens aren't here already.
There's billions of stars within a few thousand lightyears. If one of those stars was similar to earth, but cooled just 1% faster, they'd have had a million years to spread out or leave some kind of mark on the galactic neighborhood.
What's your preferred explanation for why we don't hear any alien broadcasts?
there's a few limiting factors
Nobody likes noisy neighbours. If you want to contact me ring my doorbell. Don't blast Metallica loudly and expect me to understand that you ordered the songs to spell out 'can we borrow your lawnmower?'.
I think it's because they are much more principled than me and believe that broadcasting is a form of posting, and thus counterproductive
sorry comrade, I just don't give this a lot of thought haha the other comments cover most of the counterarguments I like, much better than I could!
The universe is 13.7 billion years old. Earth formed 4.5 billion years ago, and 1 billion years later the first life forms evolved. The first Hominids evolved about 2 million years ago, modern Humans 300 thousand years ago. 12000 years ago we developed agriculture. Humans invented the radio in 1890, 132 years ago.
So humans have had the ability to transmit radio waves for 1% of the time we've had agriculture. Humans have had agricultural civilization for only 4% of our species existence. We as a aspecies have only existed for 0.086% of the time life has existed on earth. And life on earth itself has only been around for 26% of the universe's existance.
Even if we assume that life began at roughly the same point everywhere in the universe compared to earth( which is a huge assumption), that still leaves a huge margin for other civilizations on other planets to have evolved, progressed, and died out, long before we even evolved.
The odds that another planet developed sapient life which progressed to a technologically equivalent or superior level to humans at the same exact time that we did is incredibly unlikely, which I think is a far simpler explanation than the dark forest theory.
Edit: forgot to move the decimal over when converting to percentages lmao. Fixed now. Its still exceptionally unlikely, but the numbers I had were way off
That's what Hawking argues, but his guess for why they're dying out is someone else nukes them when they detected.
The same math makes one wonder why aliens aren't here already. There's billions of stars within a few thousand lightyears. If one of those stars was similar to earth, but cooled just 1% faster, they'd have had a million years to spread out or leave some kind of mark on the galactic neighborhood.
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