Earth Day: NASA Asks You to Celebrate with a Selfie

This Earth Day, NASA is inviting people across the world to celebrate the "green" holiday by sending in selfies it will then assemble into a composite image of Earth.

"While NASA satellites constantly look at Earth from space, on Earth Day we're asking you to step outside and take a picture of yourself wherever you are on Earth," their website wrote. "Then post it to social media using the hashtag #GlobalSelfie."

NASA says its earthy collage will be released in May along with a video using the images.

The social media event serves a promotional as well as celebratory purpose. NASA is publicizing its efforts to study Earth and other far away planets. The agency says it has "17 Earth-observing missions orbiting our home planet right now - and several more launching this year - [to study] Earth's atmosphere, land and oceans in all their complexity."

On a less cosmic scale, Google kickstarted Earth Day 2014 with its hummingbird, puffer fish, dung beetle and moon jellyfish doodles. Through a Google search, you can find some of the best eco-friendly events taking place this week with both Earth Day and Arbor Day in sight, The Associated Press reports.

In Columbus, Ohio, annual volunteers will do about 12,000 hours of community service at more than 150 sites planting trees, working in community gardens and cleaning up neighborhoods.

About 5,000 fourth- and fifth-graders from Oklahoma will visit their state's capital for ScienceFest Oklahoma, where they will learn about protecting the environment, conserving natural resources and using alternative fuels and technologies.

The Smithsonian's National Zoo is shedding light on the dwindling Sumatran tiger population - of which there are only 400 left - by launching an "endangered song." The song was recorded on 400 polycarbonate records designed to decompose gradually.

Even Apple is launching a campaign offering free recycling of all its used products and vowing to soon power all its stores using renewable energy.

Earth Day was founded by Gaylord Nelson, a former U.S. senator from Wisconsin.