Of course there are aliens up and about! Earth has almost been conquered and been attacked many times in the past but thanks to our Stargate program we managed to Defeat the Goa'uld, System Lords, Ori, Replicators in not only our galaxy but the Pegasus Galaxy as well, we are waging wars with the Wraith in the Pegasus Galaxy, Currently at war with the Lucian Alliance, and have an expedition team 20 Billion Light Years away from Earth in an Ancient (Lantean) war/exploration star ship.
We have made many Alliances, even with the Asgard, and Nox. Both being one of the four original great races, then after many years, they decided to make Earth the Fifth Great Race!
From these Alliances we have made many advancements in technology which some has even been integrated into modern life. We have created mighty battle cruisers that protect not only our Galaxy (Milky Way) but others as well! Others being the Pegasus and partially the Ori Galaxy.
The BC304 MKII is superior to many other ships because of the Asgard Shields and Beam Weapons. The Asgard shields are able to with stand bombardment from even the mighty Ori Motherships which can destroy the average Ha'tak Mothership in 1 attack. Also the Asgard Beam Weapons are able to destroy these mighty Ori Motherships and Asuran Warships in several seconds. Ori Motherships use the weapons fire from other ships to recharge its shields but because the Asgard Beams are so powerful, they overload their shields allowing us to destroy them.
The Asgard shared there technology with us mostly as thanks in helping destroy the Replicators. But laters the Asgards gave the Tauri (Humans of Earth) all of there currently Research and Technology as they were a dying race.
BC304 - Daedalus:
BC304 - Odyssey Firing Asgard Plasma Beams and Destroying an Ori Mothership:
BC304 - Apollo engaging an Asuran Warship:
BC304's - Daedalus and Apollo both using Asgard Beam Weapons:
Our race has even been enslaved in the past by the System Lord named Ra.
Many Years ago when Ra was in control of the planet, he would take our people through the Stargate to work on other planets to mine Naquadah.
Naquadah is a rare, super-heavy metal element used by a wide number of different races. Its most basic use is as a weapon: naquadah greatly amplifies energy, making it extremely potent if paired with explosives. Due to its unique properties, naquadah forms the basis for many advanced technologies; the Stargates themselves are composed almost entirely of naquadah. Naquadah is also present in the bloodstream of the Goa'uld, which allows them to control their technologies and sense the presence of other symbiotes. The Goa'uld have naquadah mining operations on many planets; its refined form, weapons-grade naquadah, is extremely valuable and often used as currency. Weapons-grade naquadah is so dense that two Jaffa are required to lift a quantity the size of a couple of common housing bricks, making it at least as dense as gold. Alternate forms of naquadah include liquid naquadah, used to power Goa'uld staff weapons, and heavy liquid naquadah, used to power AG-3 weapons satellites.
"This mineral is clearly the building block of all his technology."
—Daniel Jackson referring to the Goa'uld, Ra
Now before you go on saying that this is from the TV Show Stargate, I would like to say that the TV Show is indeed just a cover up for the real thing! The Stargate program is 100% real but it has not been reveled to the public yet. Someday it will be and for all the haters out there who think I'm trolling will be eating their words!
That being said, Yes. I very much believe in life and advanced races beyond our world.