Google's been busy once again demystifying life in the universe and answering all of your burning questions, such as: Is my significant other really working late? What would I see if I were standing on Mars? And what does the Mariana Trench look like?

The blogosphere is abuzz with news about the newest interactive Google Map feature: Google Latitude. The service, which debuted this morning, allows people to track the whereabouts of their friends and family—and have them do the same on internet-connected mobile devices and wireless computers. The way it works: once you opt in and select your group of followers, they can track your—or at least your device's—every move (and vice versa).

Think there may be times you want to escape some of their prying eyes—like if you're still out on the town and want your pals – but not your mom—to know where you are? No problem, according to Google spokesperson Carolyn Penner. There's a way to block anyone at anytime, she says.

Just how much detail does the app provide? In a big, wired city, it can probably find your location down to the block, Penner says. In areas where cell towers and Wi-Fi networks are few and far between, you can be tracked to a more general vicinity. Of course, if you have a GPS (global positioning system)-enabled device, the map will be the most accurate. Through the program, users can chat, text or call friends they spot on their maps.

Some critics have raised privacy concerns, but Google notes that it's strictly voluntary and users control who gets to monitor their moves. "The detection is where your device is, not where you are," Penner says. So if you forget your phone at home, your friends might just think you're playing hooky for the day.

No interest in monitoring your fellow Earthlings' every move? How about checking out what's up on Mars? Google Earth 5.0—in cooperation with NASA, the European Space Agency and other groups—now provides a "street view" of the Red Planet. The truth be told, Google Mars 3-D—which launched earlier this week—is still a bit patchy and not quite as dramatic as panning around midtown Manhattan's skyscrapers. But who knows, you might even find something worth writing home about. The service monitors Mars via composite images from satellites and even the Mars rovers. In fact, notes Google spokesperson Aaron Stein, in some views, you can even see the rovers themselves.

The latest Google Earth is also making a splash with its underwater view of the world's oceans, Historical Imagery and Touring functions. For ocean in Google Earth, which also links to video, photos and information about ongoing expeditions (we just found, for instance, an angler bringing in a catch off the coast of Japan), Google partnered with major scientific organizations including The National Oceanic & Atmospheric Association and the U.S. Navy to provide a detailed look at some of the ocean's floors. The wavy top of the ocean, Stein notes, is actually animated and not part of the satellite images, but bays, lakes and other near-land watery areas usually are (hence the Japanese fishing boat).

If you ever wondered what your new subdivision looked like before the houses came along, the archived satellite images from Historical Imagery can tell an aerial story about it and just about any other location on Earth. Of course, some spots have older images than others, but it's worth a gander. If you're thinking what we're thinking: What happens if Latitude ever merges with Historical Imagery?—you might have some explaining to do about that "late meeting" on February 4, 2009. According to Google, however, only your current location gets stored. So you can relax, and get started on the narrated tour of your last vacation destination, thanks to the new Touring feature.

Image courtesy of Google