1. Scientific Courisity - I think scientific curiosity doesn't require their making themselves known to us. In fact, in the interest of not contaminating their observation, they may intentionally hide themselves from us like a bird watcher might hide himself from the birds by building a blind.
2. Tourism - I think tourism bespeakes of components of psychological makeup similar to ours which any technological aliens may not necessarily have to have. If they do share it to some degree they may also be satisfied with telepresence through remoting sensing using techniques unknown and undetectable to us.
3. Natural resource - All forms of matter are energy. Once transformed into energy, all matter are interchangeable. To get any material resource, you will ultimately need just energy - to transform into matter, and information - to know what properties to give to the matter. So I tend to think natural resources itself will not be at any sort of premium at all once an technological civilzation masters sufficiently powerful sources of energy. If I were to guess, I woiuld say our own civilization is probably within several hundred years of economic transmutation of matter and energy. So I will guess most technological advanced civilizations woiuld already have this. So tghe only resource they need is energy.. Once energy is available, any matter required is just a form of manufactured goods, not a raw resource. There is no particularly sources of energy in our solar system (we know of) that is not as common as sand in the rest of universe. So I suspect nothing on the resource front would interest any alien civilizations in our solar system.
4. Trade - based on 3, the only items worth trading would be energy and information. Do we have any in sufficient quantity and of sufficient quality to trade with in the near future? Probably not.
5. Charity/Conservation - I suspect even our own inclination to preserve life on a particular planet would go down after one learns just how many lineages of independent life there are in the universe. Add this to the possibility that the aliens may not share the psychology of conservation and charity with us at all. So one might just assume if we can't be of steady value to them, then they wouldn't lift a tentacle to preserve us.
6. Immigration/Occupation - I suspect reasonably advanced aliens with command of economic matter - energy transmulation would not be tied to any planet, and be relatively indifferent to where they live.

So that's why I don't see any compelling reason why Aliens would be inclined to make themselves known to us.

In the video that I posted, Dr Neil said it best; if alien life forms are only one percent more intelligent than us, as we are to our nearest animal relatives, then they would consider us as nothing more than animals. They'd look at the greatest minds we have to offer and say, "Hey, this one understands astrophysics, just like little Timmy. How cute."

It would be ever so humbling, if we were even able to comprehend it, though, wouldn't it?

Presumably, any alien race advanced enough to visit us would observe our planet for a while before they visited us, and I think that after they watched the human race sufficiently, they would most likely avoid us altogether or steralize the planet.

(June 8, 2012 at 3:44 pm)Faith No More Wrote: Presumably, any alien race advanced enough to visit us would observe our planet for a while before they visited us, and I think that after they watched the human race sufficiently, they would most likely avoid us altogether or steralize the planet.

I assume they wouldn't sterilize us. If they're actually morally superior to us (which always seems to be the assumption about advanced races.) I'd think they'd understand that we're still advancing ourselves.

If they do sterilize us they're no better than we are.

The universe is a big, big place where rare things happen all the time. Who knows?

Adjusted Sanity Wrote:If they do sterilize us they're no better than we are.

My point is that they might see us as we see the smallpox virus. Are we a bad race for trying to wipe out the smallpox virus?

(June 8, 2012 at 3:57 pm)Faith No More Wrote:

Adjusted Sanity Wrote:If they do sterilize us they're no better than we are.

My point is that they might see us as we see the smallpox virus. Are we a bad race for trying to wipe out the smallpox virus?

But we aren't a virus. We're an intelligent, developing species. I assume any advanced alien race would have had similar origins and almost equally ugly histories. I doubt they just eliminate us for not being at their stage of development. It would be arrogant of them to decide our fate.

(June 8, 2012 at 3:49 pm)Adjusted Sanity Wrote: I assume they wouldn't sterilize us. If they're actually morally superior to us (which always seems to be the assumption about advanced races.) I'd think they'd understand that we're still advancing ourselves.

Why would they, having all together a different biology, psychology, history, perception, and motivation, take to our pitiful, ad hoc, variable, self-serving contrivance called morality? Rather ethnocentric of you, don't you think?

@chuck, right so, it all boils down to scientific curiosity. Since we wouldn't know enough of their physiological and neurobiological processes to determine whether or not they have any wants or needs that may imitate our own, besides a desire to learn.

Its a given, we have to accept this first premise, otherwise their race could not be technologically 'advanced' enough to achieve interstellar travel and investigation.

Likewise, would they do nothing to protect us from any internal and external threats to life on this tiny world? Would they care enough to allow us to survive so as to continue the study? Or permit our extinction as a conclusion to the investigation?

Adjusted Sanity Wrote:But we aren't a virus. We're an intelligent, developing species. I assume any advanced alien race would have had similar origins and almost equally ugly histories. I doubt they just eliminate us for not being at their stage of development. It would be arrogant of them to decide our fate.

My point is that compared to them, we may seem like what viruses appear to us. If that were true, I doubt they would bat an eyelash, or whatever aliens have, while proceeding to make sure we don't contaminate the universe.