I vote by extraterrestrial beings because if we have been visited by anything outside our world or time the most logical thing would probably be ET.
Why would ETs be the same size as us?
I think that ETs probably come in all shapes and sizes. I have a point of view about aliens, imagine the most radically shaped alien you can and then think that the real ones are probably alot more radically shaped.
Why would ETs be interested in us?
I can imagine numerous reasons, from wanting to make peaceful contact to wanting to wipe us off the face of the Earth and taking over the planet afterwards. Take you pick.
Why would ETs try to hide from us?
If they are technologically advanced to travel to our planet why would they hide, unless they've visited already and some government is hiding them from us.
Would you send your FTL ship into a planets gravitational well?
Don't know never had an FTL ship.
Why would ETs think like us?
Probably not.
Instead of ET think TimeTravellers from a Future Earth.
That would explain more about this behaviour
Maybe but if we had seen them couldn't they just alter time so we wouldn't have seen them.
It would also explain abductions and sporatic sightings.
No it wouldn't because why would they abduct humans if they are humans, that is unless they need our genes to treat an uncurable disease in the future. The sighting are probably people who want some attention or were kidnapped by some government organisation for experimentation.
If it is on the ground is it still considered a UFO?
Only if it had been flying around before it landed.
time travel is impossible. you cant alter the past and you cant disrupt the future. simple as that.
Time travel is impossible but I always say nothing is impossible it just might not be possible now.
and also the phsyics of it are impossible. its nice to dream of it but it will never happen.
Physics is constantly changing as new things are discovered, evolution is a constant and not only to physical evolution but scientific as well.
My guess is nothing is visiting us...unless Einstein was wrong and we can travel faster than the speed of light.
There may be another forms of travel that bypasses the speed of light issue and is ultimately faster.