Uncovering and explaining how our digital world is changing — and changing us.

Ten years ago today, Google Inc. went public in an offering that raised nearly $1.7 billion and valued the young Internet company at around $27 billion. The Mountain View, Calif., startup quickly put that money to work, transforming itself into much more than an online search company.

By the end of 2004, it had acquired the companies that would form Google Maps and Google Earth. It was already pushing beyond the confines of the Internet, scanning physical books to make them searchable, too. And the company launched Google.org, which, among many other projects, would seek to develop ultra-efficient vehicles, confront global poverty and analyze data to predict real-world events like flu outbreaks.

In 2006, Google picked up YouTube. In 2007, it announced Android. And in 2008, it introduced the Chrome browser.

Along the way, Google has continually expanded what online search meant, even as it pushed into areas further and further beyond its core business. In 2010, it launched Google X, which has plumbed the depths of science fiction for ideas ever since.

Here, then, is a list of 10 of the biggest, most ambitious or zaniest projects that Google has explored in its decade as a public company, most of which occurred since the launch of its secretive research division.

Self-driving cars: In late 2010, Google took the wraps off a secret effort to develop self-driving cars, aiming to turn that staple of futuristic films into a consumer reality. Specifically, the company revealed its autonomous vehicles — Toyota Prii equipped with lasers, sensors and computers — which had already logged thousands of miles along San Francisco Bay Area highways.

The company had hired several leading researchers to push the field forward, including Sebastian Thrun, who led the Stanford team that won the 2005 DARPA autonomous driving challenge. More recently, at Re/code’s Code conference in May, Google unveiled a new car built from the ground up to operate under robot control, eliminating the wheel, gas pedal and brake altogether.

Project Loon: Last summer, Google began conducting experimental trials of Project Loon in New Zealand, an effort to move more of the developing world onto the Internet through a series of connected balloons floating in the stratosphere.

As Google explained: “Loon balloons go where they’re needed by rising or descending into a layer of wind blowing in the desired direction of travel. People can connect to the balloon network using a special Internet antenna attached to their building. The signal bounces from this antenna up to the balloon network, and then down to the global Internet on Earth.”

Robot kites: Google invested in and ultimately acquired Makani Power, a renewable energy company that has developed an airborne wind turbine. The tethered wing flies in large circles like a kite, taking advantage of the higher and more consistent wind speeds at loftier altitudes. Though the company’s precise plans are unknown, the broad goal is to improve efficiency and drive the adoption of sustainable energy.

Calico: Late last year, Google launched a separate company, Calico, that early reports described as the company’s attempt “to solve death.”

It’s a silly way of putting it — every bit as accurate as saying that any biotech attempting to cure a disease is trying to solve death. But the plan is certainly ambitious. While details are still scarce, the company is focused on addressing aging and the diseases that seem to come with it.

As I wrote at the time:

Slowing the aging process promises considerable bang for the buck, because many illnesses appear to be the effect, not cause, of getting older, including cardiovascular disease, Alzheimer’s and various forms of cancer. “By the time you get really sick, it’s hard to put you back together again,” said Brian Kennedy, chief executive officer of the Buck Institute for Research on Aging in Novato. “But slowing aging delays the onset of all these diseases.”

Smart contacts: At the outset of this year, Google told Re/code its researchers had developed a smart contact lens that could measure glucose content in tears.

It would provide a way for people with diabetes to regularly check blood sugar levels without pricking their skin multiple times a day, which could have a huge impact on the long-term health of hundreds of millions of people with the disease. It may also offer applications for average consumers looking to monitor their health on an ongoing basis.

As with self-driving cars, this idea wasn’t born within Google X. Rather, the division hired leading researchers who had already spent years focused on the problem.

Jetpack: In March, Google’s “Captain Moonshot,” Astro Teller, said at TechCrunch Disrupt in New York that the research division had at least considered the idea of developing a jetpack, but that it ultimately looked too inefficient and noisy to pursue.

(Of course, it’s worth remembering that jetpacks have been operational, if hopelessly unsafe, for decades: Test pilot Robert Courter blasted into the sky strapped to a rocket-powered backpack at the 1964 New York World’s Fair.)

Space elevator?: The New York Times reported that Google X’s list of possible projects included a “space elevator,” essentially a cable or tower tethered to Earth that reaches into space, enabling the occasional visit without the fuss and expense of gigantic rockets.

Businessweek’s Brad Stone tamped down that rumor in a long story on the research division, and Teller himself said at South by Southwest last year that they aren’t actively pursuing such a project. But a Fast Company report revealed that researchers at least looked at the idea, if only long enough to realize it couldn’t be done with the current state of material science.

(Learn more about the possibilities of space elevators in the TEDx video below.)

Teleportation and levitation?: Again, these aren’t active areas of research, but Stone’s look at Google X included this tasty tidbit:

Absurdity is not a barrier to consideration. Teller and colleagues say they’ve spent time contemplating levitation and teleportation. The latter was nixed as an area for further study in part because any unique item that you would want to teleport — a Picasso, say — would have to be completely destroyed before it could be reconstituted on the other end.

Hoverboard: A Fast Company feature on Google X noted that engineer Dan Piponi tried to build a prototype of a hoverboard. The book-sized device was covered with circular magnets, applying the same physics that drive magnetic-levitation trains in China and Japan.

As Fast Company explained: “But these ‘mag-lev’ systems have a stabilizing structure that keeps trains in place as they hover and move forward in only one direction. That couldn’t quite translate into an open floor plan of magnets that keep a hoverboard steadily aloft and free to move in any direction. One problem, as Piponi explains, is that magnets tend to keep shifting polarities, so your hoverboard would constantly flip over as you floated around moving from a state of repulsion to attraction with the magnets. Any skateboarder could tell you what that means: Your hoverboard would suck.”