Satellite imagery can serve as a time machine, revealing dramatic change in just a few seconds — but can you imagine documenting almost three decades' worth of all that change, across most of our planet's land mass? A team of imaging experts, computer scientists and journalists did. Now they've unveiled the result: a global database of zoomable, animated satellite views known as Timelapse.

"We believe this is the most comprehensive picture of our changing planet ever made available to the public," Rebecca Moore, engineering manager for Google Earth Engine and Earth outreach, said Thursday in Google's blog announcement of the Timelapse project.

Moore said the project began in 2009, when Google started working with the U.S. Geological Society to make its archive of Landsat imagery available online. The team sifted through more than 2 million satellite images, adding up to 909 terabytes of data, and selected cloudless, high-quality views for every year since 1984.

Carnegie Mellon University's CREATE Lab smoothed the views into seamless animations, and Time magazine built it all into a presentation that supplements the time-lapse animations with commentaries on climate change, urban growth and the other trends that are transforming the planet.

"I've been chiseling away at this project over the last 11 months, and am in awe of the folks who helped this come together in ways I could never have conceived on my own. Some very bright minds figured out how to make the biggest video frames ever constructed, equivalent to 900,000 HD TVs next to one another," Jonathan Woods, the Time project's executive producer (and a former colleague at msnbc.com), said in an email.

Google Earth is also hosting the Timelapse zoomable map. "Much like the iconic image of Earth from the Apollo 17 mission — which had a profound effect on many of us — this time-lapse map is not only fascinating to explore, but we also hope it can inform the global community's thinking about how we live on our planet and the policies that will guide us in the future," Moore said.

When it comes to telling the story of our changing planet, one time-lapse animation is worth a thousand words. But there's more to tell. Find out more about the trends illustrated in the seven animated images you see here:

Columbia Glacier: Alaska's retreating ice reveals how climate change is changing Earth's surface.

Dubai coastal expansion: New islands are sprouting along Dubai's coastline as part of a $14 billion land reclamation effort, arguably the largest project of its kind.

Irrigation in Saudi Arabia: Agriculture amid the deserts of Arabia? It's a growing concern, thanks to huge irrigation projects that take advantage of underground rivers and lakes. The water won't last, though: Hydrologists estimate that it'll be economical to pump water for only about 50 years. 

Lake Urmia drying up: Iran's great salt lake is not as great as it was, and the reason for that is in dispute. The Iranian government blames climate change and drought, while critics blame the dams that have been built around the lake.

Brazilian Amazon deforestation: Satellite imagery documents the loss of Amazonian forest land in Brazil due to road-building, logging and agricultural clearing.

Las Vegas urban growth: What sprawls in Vegas doesn't stay in Vegas. Landsat pictures reveal how urban development has spread out around Nevada's biggest city over the decades.

Wyoming coal mining: The Black Thunder mine in Wyoming's Powder River Basin ranks as the largest single coal mining complex in the world, according to Arch Coal, its operator. Satellite imagery shows how the mine has spread out over the decades.

More time-lapse videos:

• One World Trade Center rises
• Shuttle Endeavour traverses L.A.
• Time-lapse gallery from Photoblog

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the NBC News Science Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Forty years ago today, the first in a string of Landsat satellites was launched to keep continuous track of our planet — and on the 40th birthday, Landsat's handlers demonstrated that satellite observations are the gifts that keep on giving. But for how much longer?

"Landsat has really become the gold standard of remote sensing from space," Anne Castle, the Interior Department's assistant secretary for water and science, said during a birthday celebration at the Newseum in Washington. "It's provided an invaluable, indelible record of the recent history of our planet."

From the beginning, Landsat was designed as a system that would provide freely available data about Earth's condition — documenting agricultural shifts, urban development, deforestation, floods and the impact of climate change and natural disasters. On the flip side, Landsat has chronicled the planet's ability to bounce back from disaster.

The Mount St. Helens eruption of 1980 serves as a perfect example: The time-lapse video below shows how the blast created a dead zone around the volcano in Washington state, and how Mother Nature slowly crept in to reclaim the gray terrain. You'll also see how Landsat tracked the rise of Beijing, the shrinkage of the Aral Sea and other "top 10" changes in our planet's landscape.

Castle said Landsat has provided a "thoroughly objective, continuous look at ourselves in the mirror since 1972," when the first Landsat satellite was launched into polar orbit from Vandenberg Air Force Base on July 23. In a NASA news release, she went even further, calling Landsat's data archive "the world's free press, allowing any person, anywhere, to access vital information without charge."

Landsat's past and future
This "free press" is paid for by the federal government, at an estimated cost of 80 cents per person per year. The seven-satellite Landsat project is the result of a long-term collaboration between NASA and the Interior Department's U.S. Geological Survey as well as the Commerce Department's National Oceanic and Atmospheric Administration.

"Landsat has given us a critical perspective on our planet over the long term and will continue to help us understand the big picture of Earth and its changes from space," NASA Administrator Charles Bolden said in the news release. "With this view we are better prepared to take action on the ground and be better stewards of our home."

The eighth satellite in the series, now known as the Landsat Data Continuity Mission, is due for launch from Vandenberg in February 2013. Once it's in orbit, LDCM is to be renamed Landsat 8, joining the 28-year-old Landsat 5 and the 13-year-old Landsat 7 spacecraft on the job.

And then what? That's the problem. The most important benefit of the Landsat program is the continuous, long-term monitoring of the planet's ups and downs — and some observers worry that not enough money or attention has been devoted to what comes after Landsat 8. If, heaven forbid, one or both of the other satellites should go on the blink before LDCM is launched, a 40-year-plus chain would be broken. And Landsat 5 is already faltering.

In May, the National Research Council issued a report saying that U.S. earth observation systems were in an increasingly precarious position due to budget shortfalls, launch failures and shifts in mission plans. "The projected loss of observing capability will have profound consequences on science and society," University of Washington atmospheric scientist Dennis Hartmann, the chair of the committee that wrote the report, warned at the time.

Even during today's Newseum celebration, concerns about the future cast a bit of a pall over the party. Tom Loveland, a USGS senior scientist at the Earth Resources Observation and Science Center in Sioux Falls, S.D., acknowledged during the press briefing that LDCM was currently cast as the last of the Landsat line.

"We still are on a tenuous path, in which we don't know when the next mission takes place," Loveland said.

New ways to use the data
Amid Landsat's midlife crisis, scientists keep finding new ways to use the database that's been built so far. Waleed Abdalati, chief scientist at NASA Headquarters, touted the NASA Earth Exchange, or NEX, which can help scientists easily put together mosaics of satellite imagery "like a giant jigsaw puzzle."

Google is in on the celebration as well: On its Lat Long Blog, the company highlighted its work with USGS and Carnegie Mellon University to create a monster series of interactive time-lapse videos. "With them you can travel through time, from 1999 to 2011, to see the transformation of our planet ... whether it’s deforestation in the Amazon, urban growth in Las Vegas or the difference in snow coverage between the seasons," Google's Eric Nguyen and CMU visiting scholar Randy Sargent wrote.

The Google Earth Engine is among the new tools being developed for mining the quadrillions of bytes of data in the Landsat archive.

Will Landsat still be going 40 years from now? Maybe there'll be a whole new approach to Earth observation that will make the current system and data set look laughably obsolete. But for at least the next couple of decades, if we're going to chronicle the effects of climate change on Earth's surface in a methodical manner, we're going to need Landsat.

"I don't think it's an overstatement to say the success of humanity hangs in the balance," NASA's Abdalati said. Do you agree? Feel free to weigh in with your views, or birthday wishes, in the comment space below.

More from Landsat:

• Satellite sees what sprawls in Vegas
• Get to know your planet better
• Dazzling delta seen from space
• Slideshow: Earth as art
• More artistic Earth views

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the dwarf planet and the search for new worlds.

What sprawls in Vegas doesn't stay in Vegas. Time-lapse images from the Landsat series of Earth-monitoring satellites reveal in false-color, multispectral imagery how urban sprawl has stretched out from Nevada's "Sin City" over the past four decades. This latest video was posted by NASA in honor of the 28th anniversary of Landsat 5's launch on March 1, but the pictures actually go back to 1972, when the Landsat program began. Such images help planners keep track of the pace of development, which may affect future water use, zoning regulations and other policies. Want to see how your own area has changed between 1975 and 2000? Check out this "ChangeMatters" viewer from ESRI.

More cool views from Landsat:

• Get to know your planet better
• Dazzling delta seen from space
• Slideshow: Earth as art

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

NASA

Silt washes into the Atlantic Ocean from rivers in Guinea-Bissau, a small country in West Africa, in this false-color composite image from the Landsat 7 satellite.

You're excused if this picture triggers a flashback to a trippy "Space" jam at a Grateful Dead show, but chill out: It's just an image of Guinea-Bissau, a small country in West Africa, made by the Landsat 7 satellite as it peered down at Earth from its 438-mile-high orbit.

The patterns in the country's shallow coastal waters are created by silt that's been carried by the Geba River and other streams into the Atlantic Ocean. However, this isn't what the country looks like to the naked eye in outer space. Instead, the color-coded image was produced using infrared, red, and blue filters to bring out details in the silt. This online tutorial explains more about the trippy color scheme.

Click through this year's "Earth as Art" slideshow for more out-of-this-world Earth imagery.

This picture of Guinea-Bissau serves as one of the final visual treats in our Cosmic Log Space Advent Calendar. For additional views of Earth from space, check out these past offerings. We've also included links to other online Advent calendars that have been serving up space images daily since the beginning of the month:

• The Cosmic Log Space Advent Calendar so far
• Door 1 for Dec. 1: Shuttle in spotlight
• Door 2 for Dec. 2: 'Alien' lake seen from space
• Door 3 for Dec. 3: Egypt's river of light
• Door 4 for Dec. 4: Tallest building reaches for the sky
• Door 5 for Dec. 5: Russia's dazzling delta
• Door 6 for Dec. 6: Space skipper vs. the world
• Door 7 for Dec. 7: Pearl Harbor from the heavens
• Door 8 for Dec. 8: Listening for E.T.
• Door 9 for Dec. 9: Blast from the past
• Door 10 for Dec. 10: Volcano caught in the act
• Door 11 for Dec. 11: Chronicling climate change
• Door 12 for Dec. 12: Happy St. Lucy's Day
• Door 13 for Dec. 13: Viva Las Vegas
• Door 14 for Dec. 14: Don't wake the volcanoes
• Door 15 for Dec. 15: Stairways to heaven
• Door 16 for Dec. 16: White Christmas in the Midwest
• Door 17 for Dec. 17: Tracks in the sky
• Door 18 for Dec. 18: Amelia Earhart's final resting place?
• Door 19 for Dec. 19: Lunar eclipse as seen from space
• Door 20 for Dec. 20: Our pale blue dot
• Door 21 for Dec. 21: Celebrate the longest night
• The Big Picture at Boston.com: Hubble Advent calendar
• Planetary Society: Solar system Advent calendar
• Zooniverse Advent calendar

Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).