I’ve always wondered how astronomers can actually observe galaxies that are millions or even billions of light-years away. What exactly are we seeing when we look at them?
And when scientists say there are hundreds of billions, or possibly trillions, of galaxies in the observable universe, how do they know that if we obviously haven’t seen and counted every single one?
As a geologist we talk in millions and billions of years regularly and it’s part of our thing to realise how small and insignificant our lives and humanity is in general.
But as an amateur astronomer, the vastness and time of space is just another level.
The age of the Earth is a significant fraction of the age of the universe so we are not totally divorced from the timescale.
Age of Universe: ~13.8B years
Age of Earth: ~4.5B years
Life on Earth: ~3.7B years
Assuming those estimates are correct, there has been life on earth for about a quarter of the time since the Big Bang. The solution to the Fermi Paradox could well be that we’re simply among the first species able to look out into the stars. Maybe the Universe is just getting started.
Or we could be about to add a data point to the great filter theory, take your pick 😉
If by we you mean humans, IDK it’s looking pretty dicey at the moment. We as in Earth? I think will be just fine a million or so years after we’re gone, and in that time other intelligences may rise. Maybe octopi start forming complex social groups, or chimpanzees fill the niche we leave, or the fungal network finally reaches critical mass and becomes a planet-spanning superconsciousness and catapults itself into the space age by interpreting ancient human artifacts. I think Earth is gonna be a galactic contender. Whether humans are around when that happens is another question.