Science can offer some general idea about aliens, as long as they are locals. It is implied here that they are coming from Milky Way, which we mapped out to a finer detail and whose evolution we understand quite well.
(I'll use here "B" as abbreviation fro Billion)
Milky Way is about 12B years old, while universe is about 13.4B years old. So Milky Way is among the oldest of galaxies in the universe. It took 4.5B years for intelligent life to evolve on Earth. That means that Milky Way should be teaming with intelligent life by now.
Same as we have planetary habitable, Goldilock, zones around stars, we have a galactic habitable zones.
On a scale of solar system the main life creator would be planet, but on a galactic scale it would be a supernova. When supernova goes bang, two things happen, one is that they throw out lots of rocks, second one is they release lots of radioactivity. Lots of rocks is great for life because rocks form into planets, but as we know, radiation is a really nasty show stopper.
So main question here is a balance between good and bad that supernovae produce. Closer to the center of Milky Way stars are packed very close to each other, so much so, that if Earth was located there, at night, the nearest stars would be as bright as street lamps. High star density near galactic center means that when supernovas explode there are lots of nearby planetary system that get completely sterilized by the radiation. So, at the best, near the Milky Way's center life is constantly going through start-stop cycles. Approximately speaking and counting from the center, first third of Milky Way's radius is pretty much dead zone.
Further away from the galactic center, say from the end of the first third of the radius all the way to the rim, conditions for life gradually improve. About 2/3 of radius away from the center, conditions for life are nearly perfect. There is still lots of rocks to form planets, but supernovas are spaced out so far that planetary sterilizations with radiation is not anymore a big deal. And this zone is quite wide, stretching out just a bit less than the whole 2/3 of radius.
And finally, on the very rim of the Milky Way, stars are spaced out so far from each other, that there is simply not enough rocks to form planets and dead zone starts again, this time stretching out into the intergalactic space.
Now, so far that was a nice geometric picture of where the best place for life is. Close to the galactic center is bad, about 2/3 away is just perfect. That's great, but we have to take into the account that 12B passed since Milky Way started forming. Life formed on Earth rather quickly and intelligent life formed after 4.5B years. That tells us that there was plenty of time for intelligent life to evolve all over the Milky Way. Actually, after about 3B years, around that 2/3 spot, conditions for life became almost perfect.
Now all the above was simplified, just to make it easy to understand. When all the maths is crunched and both location along the galactic radius and the galactic history are taken into account,
it turns out that 77% of intelligent civilizations in the Milky Way are 3.5B years older than ours. This scientific study was done quite recently, so it means that the best and the most accurate data and the most tried and tested mathematical models were used.
And that is very, very bad, because it tells us that we are far behind the most of Milky Way's intelligent civilizations. We are far more primitive relative to an average Milky Way civilizations than say, Amazonian uncontacted tribes are relative to New Yorkers, since there is only about 15,000 years between these two and 3.5B years between us and aliens. 3.5B years is a lots of time for creation unbelievable technology and discovery of a new scientific principles.
By the way, it's interesting to ask where are we on the galactic radius. Are we any close to that balmy 2/3 of the radius? Unfortunately, here we are completely out of a luck. Sun's planetary system is just outside the central lifeless galactic zone, somewhat on the periphery of the galactic habitable ring. Essentially, as Milky Way got older, less new stars were formed and less supernovae exploded, so the galactic habitable zone started spreading out a bit. We just stroke it lucky because Milky Way aged a bit.
Now enough of science.
Understanding of the evolution of the habitable galactic zone creates a context that leads us to some unpleasant and unexpected conclusions related to UFOs.
First, on the galactic scale, we are worst off than Hilly Billies. So marginal that we have nearly zero negotiation power.
This clearly shows why aliens are arrogant at worst and patronizing at a best when communicating with us. This bigger scientific picture, described above, strongly supports idea of alien abductions. From alien point of view, they would have opportunity to look deep into their own past and the first thing they would like to do would be collecting genetic samples.
Lets say, that situation was reversed, would we do abductions? I would say yes. And even worst, we would most likely hunt and kill them just for sport and than show the chase on reality TV. If we captured a living Neanterthal (or lets say Sasquatch ;-) wouldn't we scoop his skin samples, stick needles and insert tracking devices into him, while it's still alive. Sure we would. Would we cut him into pieces and display him in a museum. Absolutely. Republicans would just say that the captive was an animal, not a human and Democrats would say that he's an important scientific specimen needed to advance our knowledge ;-).
And just for fun, here is a list of
supernovae candidates closest to Earth. Nearest one is 150 light years away.
Keep watching the sky ;-)