why are you so sure?
if it was out there, you think Hubble would notice it?
We can't resolve individual stars in other galaxies, or even in most of our own -- if we can't see an entire bleeping star, blazing away for the universe to see, why would we think we would see alien space crafts & space habitats and what not?
advanced aliens would not aim their streetlights our way, and even if they did, we couldn't detect it
human level cosmology is not a precision science, the error bars on all observations are significant, and Hubble's myopic inability to see the Apollo landing sites on our own moon, and ~50 pixels on Pluto in our own star system, should not make us cosmologically cocky about our "space eyes on the skies"
If you were walking in a jungle, and got dirt in your eyes, would you assume there were no scorpions, poisonous millipedes, snakes, pumas, jaguars or others out there?
"Seeing is believing" = too late / lunch (for those with better eyes)
better safe than sorry?
The wise default assumption would be:
- they are out there (until proven otherwise)
- they are hostile (until proven otherwise)
- they are not going to willingly reveal themselves
- they will try to deleteriously influence earth history
- as much as possible
- as quickly as possible
Again, that is the ordinary run-of-the-space-mill default position. Claiming that the entire galaxy or universe is devoid of intelligent life, when one of one well-surveyed star systems has such, would be the actual extra-ordinary claim. As would be the claim that, if they exist, they are going to be friendly and help humanity in any way -- that might be possible, but would be extremely unusual & extra-ordinary.
The ordinary, run-of-the-mill, default assumptions would be:
If that were to turn out to be the case, we
shouldn't be surprised. Anything else (earth is the only inhabited planet in the universe, they're friendly)
should be exceedingly surprising, hence an extra-ordinary claim.
yes, we should
expect them to exist... and even to have
visited us...
and if we should expect them to have
visited us (physically, materially, matter travelling
slower than lightspeed) how much more should we expect them to have
contacted us (informationally, light traveling
at lightspeed) ?
crashed weather balloons on earth are not evidence of advanced
anything, much less advanced space aliens from the other side of the galaxy or universe...
but if Carl Sagan or his great great great … great great grandfather Abraham ever claimed to receive
meaningful intelligible cogent articulate audio-visual messages from super-intelligent heavenly powers, then we
shouldn't be surprised
(it would not be an extra-ordinary claim, "life in the universe communicating" is the completely normal run-of-the-mill off-the-shelf presumable assumable default presupposition -- no exotic DM or DE supersymmetric axions from inflationary fields from String Theories dozens of Planck-scale hyper-dimensions required... just "life in the universe communicating"... momentous claims are not automatically extra-ordinary... if Idaho ranchers reported massive earthquakes heralding the next Yellowstone super-eruption, which we expect to happen geologically soon, that would be momentous headline news... but by no means extra-ordinary... already been made into a movie)