Earth

Happy Earth Day! It's been 43 years since Wisconsin Sen. Gaylord Nelson celebrated the very first Earth Day on April 22, 1970. It's not yet a federal holiday, but Earth Day is celebrated by schoolkids from coast to coast (along with many adults). Of course, it goes without saying that for some folks, every day is Earth Day. Here are seven things you might not have known about Earth Day (and the spirit of environmentalism it represents): * More than 1 billion people in 192 countries are doing something to mark Earth Day this year, according to estimates from the Earth Day Network . In Veracruz, Mexico, volunteers will clean up beaches to improve the habitat for sea turtles.

Tobacco users on the UCLA campus will have to find a new place to light up as the university enacted its tobacco ban on Earth Day. UCLA Chancellor Gene Block announced the change last October following a call from UC President Mark Yudof to go smoke-free across the UC system by 2014. The Westwood campus' new policy will prohibit “cigarettes, pipes, cigars, chewing tobacco and all other forms of tobacco, as well as e-cigarettes,” according to a statement on the school website.

Earth Day 2013 gets its own Google Doodle today, an honor that kicks off a day dedicated to reminding us to tread gently on this planet that we all share. The Earth Day 2013 Google Doodle unveils a scenic mountain meadow, with a babbling brook and a lake that's home to a school of fish. Click around and you'll see more: fireflies, a bear emerging out of a cave, a -- what is that? a badger? -- as well as ants, and dandelions you can "blow out. " The passing of the seasons provides a backdrop, all under the watchful, alternating eyes of the sun and the moon.

The Grand Canyon Railway is sprucing up its 90-year-old steam train with a green makeover for Earth Day, which is Monday (today). The former Atchison, Topeka & Santa Fe train will run on eco-friendly recycled vegetable oil for the ride to the Grand Canyon. Grab a seat this month and receive half off a future visit. The deal: Diesel trains operate daily from Williams, Ariz., to the south rim of the Grand Canyon. It's a 130-mile round-trip ride with observation cars that provide a front-row seat to the spectacular desert landscape.

Heija Yan took a drag from his cigarette as he approached Powell Library on the UCLA campus Monday, not noticing that the ashtrays were empty and askew. The electrical engineering graduate student had no idea that the university had enacted its tobacco ban on Earth Day. He was profoundly apologetic. “I know others don't like the smell around them, but I know [the library] is a popular place to smoke so I thought I'd be OK,” he said, while flicking the cigarette butt into the tray.

Heija Yan took a drag from his cigarette as he approached Powell Library on the UCLA campus Monday, not noticing the ashtrays were empty and askew. The graduate student in electrical engineering had no idea the university had enacted its tobacco ban on Earth Day. "I know others don't like the smell around them, but I know [the library] is a popular place to smoke, so I thought I'd be OK," Yan said, flicking the butt into an ashtray. UCLA is the first school in the UC system to implement the ban, following a call by President Mark G. Yudof for all 10 UC campuses to go smoke-free by 2014.

Google said the latest version of Google Earth will allow users to navigate their way through the 3-D map using hand gestures, giving a strong vote of confidence for Leap Motion's technology. As seen in the video above, users can control Google Earth 7.1 using Leap Motion's "motion-sensor" control, which works like Microsoft's Kinect device for the Xbox 360. Leap Motion is set to begin selling it in stores next month. The San Francisco company last year unveiled the technology in a series of YouTube videos that drew rave reviews.

NASA scientists announced Thursday that the Kepler mission had confirmed finding three planets , slightly larger than our own Earth, orbiting in their stars' so-called habitable zones -- that "Goldilocks" region where temperatures are not too hot and not too cold. Researchers don't know for sure, but the planets' sizes and proximity to their stars mean that they could be rocky and could have liquid water, two attributes thought necessary for a planet to harbor life. What is certain, the scientists said during a press conference Thursday, is that the discoveries mark yet another step forward in the space agency's quest to find an Earth-sized planet in a star's habitable zone.

"Oblivion" will make you remember, not forget. This Tom Cruise vehicle is a throwback to the days when on-screen science fiction was about speculative ideas rather than selling toys to tots - think of it as the most expensive episode of "The Twilight Zone" ever made. "Oblivion" is not perfect. Its dystopian story makes no apologies for its familiarity, echoing such films as "The Planet of the Apes," "The Matrix," "2001" and even "Wall-E. " And expecting the wheels not to eventually begin to fall off its pleasantly complicated, head-spinning plot (based on the director Joseph Kosinski's graphic novel)

Yellowstone, Yosemite and Sequoia were the first national parks, and Pinnacles in Central California the most recently designated one, though the land had been set aside as a national monument since 1908. National Park Week provides an incentive to go see "America's best idea" firsthand with free entry and free events on Earth Day and beyond. The deal: The 401 national parklands - parks, monuments, historic sites, etc. - will be fee-free for five days during National Park Week, which runs Saturday through April 28. Not all parks charge an entrance fee, but those that do will waive them.