paladin181: If they are visiting Earth, perhaps the Earth itself ifs the entity they are coming to see, and it talks to them; we are nothing more than an annoying parasite, a flea infestation.
Breja: Maybe they just want to talk to the whales.
Whales and NUUKLEAR WESSELS should be good enough a reason for any space traveller to visit this planet in this time!
72_hour_Richard: one level of reasoning the movies often miss, is that if these aliens have the advanced technology to travel aaaaall the way to Earth, they must surely possess the technology to easily mine any countless number of asteroids and uninhabited planets.
Yeah.
V was kind of great, at least the original miniseries in which the reptilians came in human disguise just to take over the planet.
But then in The Final Battle the plot started to go south, or which ever way in space means bad.
That human/reptilian hybrid kid, OK, I guess that's a nod to the UFO lore, but when they had that massive section in their flying saucer where they stored living humans in some jelly to be flown back to their home planet... as food?!
From any rational point of view the logistics of that would never make any sense. Of course it was for horror effect, we get that, you can only rip those humans faces that many times, you need to think something else. But they should have run the script through some science advisor at least once before shooting.
One of the reasons why Star Trek, Babylon 5 and some other shows are good, is that they have at least made some attempt to keep some scientific reality in them. Maybe not that much, but enough at least.
72_hour_Richard: why bother studying us if they have no plans on initiating contact?!
Well, the Star Trek explanation works actually very well.
They study civilizations which are about to become space travelling species in the near future, but don't make first contact, because that species must take the first step towards it.
That's kind of how it was done in 2001: A Space Odyssey too. The monolith on the moon couldn't be found accidentally, finding it required spaceflight capability.
The question is of course, would any real aliens be bothered to play such games with technological advancement.
They could just come and take whatever they want, or make the first contact happen on whatever terms they wanted to dictate.
Or make us mine gold for no real reason, like Anunnaki did, back in the day.
timppu: One thought that intrigues me though, which I admittedly got from the Farscape scifi TV series, is that would it be plausible to be a lifeform that doesn't need e.g. atmosphere, but e.g. energy from the suns would be enough to keep them alive? A lifeform that can travel in space, not bound to one planet with its own atmosphere.
Virus? Bacteria? And such?
Sure, it's possible, at least if you count those as lifeforms. Panspermia and all that stuff.
Now if you meant something that can think and actively choose where to go in space, that would be much harder. Our knowledge about physics can be incomplete, but some basic concepts are probably true.
So how would such a lifeform ever leave their home planet, other than debris from asteroid collision and other similar events? Once in space, how would that lifeform change its course?
Some very big practical issues.
But as far as such life existing overall goes, sure it's possible. In theory at least.
