We all believe, accept that humanity is not alone in
this universe. Most take for granted that we're not
even alone with our galaxy. And if you do stand with
the absolute majority on this one, there are quite a
number of points you must also accept as true, not
the least of which would be...
#1. Aliens know that we're here.
This is always one of two facts about alien civilizations
that blows my mind; they know that we are here.
No, not from our TV and radio signals. They're far too
weak to be detectable and even if they could pick them
up they'd be nothing but noise. No, aliens know that
we're here because they can read our biosignatures.
We humans only found our first exoplanet about 30 years
ago or so, and already our tech can find biosignatures
over 100 light years away.
NOTE: This is untested science. Meaning, we can detect
what we identify as biosignatures but unless and until
we can confirm any biology it remains more or less
theory...
The earth has been hosting life for more than 3 billion
years, and that life was so prevalent that it actually
sparked it's own extinction event some 2 billion years
ago, when life so saturated the atmosphere with oxygen
that it sparked a mass die-off.
Yuck.
Anyway, let's go back THAT far, the 2 billion years,
and say we've only been detectable since then...
If aliens are within 100 light years from us they could
likely detect our technosignatures as well. In which
case, yes, they would know that a civilization exists on
earth.
#2. Alien signals are reaching us CONSTANTLY.
Alien signals are, to us, what microbes were to humans
prior to the invention of microscopes. Even when people
had worked out that they had to be there, they had no
way of seeing them.
Alien signals are reaching us though, from every
direction.
#3. The odds overwhelmingly favor alien tech sent to
the earth.
Even if there's only a 1-in-a-million chance that an
alien civilization will send technology towards us,
it's been 2 billion years since the Great Oxygenation
Event I chose as our starting point (taking place
well over a billion years AFTER life first appeared
here).
2 billion == 2,000 million
So if there's a 1-in-a-million shot for a civilization
to send tech, figure on 2,000 probes/ships sent our
way. Of course, looking at these time spans we could
likely only find them indirectly -- impressions in
the fossil record, or (more likely), anomalous elements
that had to be introduced from outside an environment.
Oo! A better place to look for this tech would be in
our solar system! If it's active, that's where it
should be, and if it's dormant it has a better chance
to survive there, even in fragments, than a geologically
active earth.
#4. If the theory that Mars once hosted life is true,
and even that Mars may have spawned life prior to the
earth, alien tech would have been directed towards
Mars.
Mars could have been displaying detectable biosignatures
for 500 million to a billion years prior to the earth.
A reasonable person might reasonably argue that 500 or
more probes/ships sent towards Mars is not unreasonable.
So, the earth would not be our only place to search.
#5. We can't bet on all aliens being god like.
It's likely that any civilization sending tech out way
would make great efforts to ensure it is free of
contamination, as we do. And we fail all the time.
We're not going to get alien DNA, right? If their tech
has been shattered, floating around our solar system
for a million years the DNA is "Gone," in a sense. But
it's basic components are not.
Adenine (A), thymine (T), guanine (G), and cytosine (C)
are all known from meteorites. They clearly have zero
difficulty surviving for a very long time, even
surviving the fiery "Re-entry" into our atmosphere...
though in their case it would be "Entry" and not
"Re-entry."
This alone, even without working out any sequencing,
could tell us a lot -- starting with whether or not
they even had DNA!
Alien biology is big. It's huge. It is perhaps the
single greatest scientific discovery that we can
confidently predict to lay ahead. And yet it is no
priority for us what so ever. It's insignificant.
Nature, the magazine, oh so respected, of so "Science"
and all, called $11 billion for a Mars return mission
an "Astronomical" price. Biden has already wasted some
$175.9 billion on the Ukraine, and counting.
Unlimited wealth for somebody else's war, nothing for
the search for life...
Even if we just take the money Biden is given to the
Palestinians, when diplomats and political experts
agree that they would hate us for free, would get us
about 90% to a Mars return mission. But paying people
to hate us is more important than the greatest
scientific discovery we can realistically expect within
a lifetime.
-- https://jtem.tumblr.com/tagged/The%20Book%20of%20JTEM/page/5
Blow the roof off of evolution: Alien biology