The GOES satellites, East and West, are in geostationary orbits 22,300 miles above Earth. That allows them to monitor a whole hemisphere's weather 24/7 from a fixed position above the the planet. (GOES stands for Geostationary Operational Environmental Satellite.) NASA takes the GOES satellites' readings on cloud cover and overlays them on a full-disk "Blue Planet" view of the oceans and land masses. The result is a hemisphere-wide snapshot of Earth like this one, produced every three hours.
Although this picture marks the end of our Advent calendar, you can keep the satellite images coming throughout the next year with GeoEye's free desktop calendar. The calendar consists of a series of computer desktop wallpaper images, highlighting GeoEye satellite views from the past 13 years. DigitalGlobe also offers 2013 calendar packages with an Earth-from-space theme, for purchase through the company's online store.
Seeing our planet from space tends to broaden a person's perspective on Earth's problems and preciousness: That's what Apollo 17's astronauts discovered 40 years ago this month when they snapped the first and most famous "Blue Planet" picture. Here's hoping that the past month's pictures of Earth as seen from outer space have broadened your perspective as well. Have you seen 'em all? If not, graze through the links below.
The spectacle that Burbank saw from the International Space Station, and that other observers watched from the world below, was quickly nicknamed the "Great Christmas Comet of 2011" and the "Star of Wonder." Lovejoy lit up the skies of the Southern Hemisphere — but most northern observers could experience it only vicariously.
Next Christmas, there's a chance that the Northern Hemisphere will get in on a star of wonder: Comet ISON, which is due to make its circuit through the inner solar system next November and December. It's still too early to say whether ISON will be the "Great Christmas Comet of 2013" or a great disappointment. But astronomers are keeping a close eye on the comet, and some are wondering whether they're already seeing the start of a cometary tail.
This look back at Comet Lovejoy serves as the penultimate picture from the Cosmic Log Space Advent Calendar, which has been offering up daily images of Earth from space through the month of December. Check back on Christmas for the final picture of this year's series — and check out the links below for the rest of the Advent calendar images:
This visualization shows Saturday's extent of Arctic sea ice, as charted by the National Snow and Ice Data Center. The readings have been overlaid on NASA imagery of the Northern Hemisphere. The orange line indicates the median extent of sea ice on the same calendar date for the 1979-2000 time period.
If Santa Claus is getting the feeling that someone's looking over his shoulder as he rushes to make his Christmas deadline, he's not wrong: A succession of satellites is monitoring his North Pole workshop and the rest of the Arctic on a daily basis. Based on the satellite readings, the long-term outlook is worrisome, for Santa and the rest of us as well.
This image shows the extent of Arctic sea ice, based on the latest microwave data from the Pentagon's DMSP-F17 satellite. Those readings are compared against the median extent for the same date over the 1979-2000 time frame. That median extent is indicated on the photo by the orange lines.
Earlier this month, the National Oceanic and Atmospheric Administration said in its annual "Arctic Report Card" that glaciers and sea ice retreated at a record rate this year, and that sea level rise has accelerated in the region. What's more, those changes are affecting ecosystems in the far north — spurring marine phytoplankton growth while putting extra pressure on land species such as lemmings and the Arctic fox.
There's also a spillover effect on ecosystems farther south. "What happens in the Arctic doesn't always stay in the Arctic," NOAA Administrator Jane Lubchenco said. "We're seeing Arctic changes in the ocean and the atmosphere that affect weather patterns elsewhere."
Today's visualization of the North Pole's ice is the latest offering from the Cosmic Log Space Advent Calendar, which features daily images of Earth from space through Christmas. Try these other visual goodies from the calendar:
Correction for 9:15 p.m. ET: I originally referred to the median extent of Arctic sea ice, but changed that reference to use "average" instead — which was an ill-advised move. Generally speaking, an "average" value refers to the mean, which can be quite different from the median. Here's an explanation from Purplemath that lays out the difference. Thanks to commenters for pointing out the distinction. (I also fixed a typo referring to "sea level rice.")
False-color radar imagery shows the Ganges Delta in Bangladesh, as seen by the European Space Agency's Envisat satellite in 2009. Standard radar images do not detect color. In this case, readings from three different satellite passes were analyzed, and the different colors reflect the surface variations that occurred between those passes.
If you still have to send out your season's greetings, take your pick from a spectrum of holiday e-cards featuring spacey imagery from the European Space Agency.
The ESA selected pictures that have a festive look — such as this Envisat radar view of the world's largest delta, formed by the confluence of the Ganges, Brahmaputra and Meghna rivers in India and Bangladesh. This particular photo focuses on the Bangladeshi part of the delta.
Radar readings can show differences in surface height and reflectivity, but they can't show color directly. This picture combines radar data from three different satellite passes — on Jan. 20, Feb. 24 and March 31, 2009 — and uses the different colors of the rainbow to show the surface changes that occurred between passes. Envisat, the world's largest civilian Earth observation satellite, was launched in 2002 but went out of contact this year.
Today's gander at the Ganges Delta is one of the last offerings from the Cosmic Log Space Advent Calendar, which has been serving up daily views of Earth from space this month. For more spacey goodies, follow the links below:
From left to right, you can see the pyramids of the Pharaohs Menkaure, Khafre and Khufu, with the Sphinx sitting southeast of Khufu's Great Pyramid. (North is pointing toward the upper right corner of the frame.) Several smaller, unfinished pyramids lie to the south of Menkaure's monument, and fields of rectangular, flat-roofed tombs sprawl to the east and west of Khufu's pyramid. There's a golf course right next to the pyramids, and the streets and buildings of El Giza spread out to the picture's right edge.
The Pyramids at Giza date back 4,500 years, which makes them at least a millennium older than the oldest Maya pyramids.
This view of the pyramids from space serves as today's offering from the Cosmic Log Space Advent Calendar, which serves up a fresh picture of Earth as seen from space every day until Christmas. Click on the links below to sample the calendar's other visual goodies:
This satellite image of the ruins of Mayapan, on Mexico's Yucatan Peninsula, hints at the apocalypse that befell a Maya kingdom hundreds of years ago.
Mayapan is considered Mexico's last Maya capital, and represents one of the largest assemblages of Maya ruins in the Yucatan. The city was built after the Maya revolted against the lords of Chichen Itza. The largest pyramid is the Castle ("El Castillo") of Kukulkan, made as a smaller replica of Chichen Itza's El Castillo pyramid. Mayapan also is home to many circular buildings, or observatories. The Maya's astronomical knowledge helped them predict the exact time of solar and planetary events and aided in the creation of precise calendars.
The city reached its zenith in the 13th century, but in the mid-1400s, factional strife led to Mayapan's decline. The rulers were killed off by a rival family during a revolt, important buildings were set ablaze, and the city was largely abandoned. By the year 1500, an epidemic drove out the stragglers. The University at Albany's Mayapan Archaeology website delves more deeply into the city's life and death.
This overhead view of Mayapan was captured by GeoEye's Ikonos satellite in 2001, from a height of 423 miles (681 kilometers). It serves as a tribute to the Maya calendar turnover on Dec. 21, as a celebration of the day's non-apocalypse — and as the latest addition to the Cosmic Log Space Advent Calendar, which has been serving up views of Earth from space on a daily basis during the holiday season. Follow the links below to catch up on the calendar's previous entries:
It may look as if a cotton ball is floating over Mount Fuji in this satellite image, but it's actually a cloud — the kind of cloud that's known to give an otherworldly look to Japan's highest peak.
This picture was snapped by DigitalGlobe's WorldView 2 satellite on Sept. 20, and it's currently the front-runner in the company's contest to select the year's top image. Cast a vote for your favorite on DigitalGlobe's Facebook page, and check back in January to find out which picture wins out.
The perspective from above — 478 miles (770 kilometers) above, to be exact — just adds to the eerieness.
This cottony mountaintop picture is today's offering from the Cosmic Log Space Advent Calendar, which serves up a fresh image of Earth from space every day from now until Christmas. Click on the links below to gather up the goodies you may have missed:
The Great Blue Hole is one of the natural wonders of the world, lying off the coast of Belize in the midst of the Lighthouse Reef Atoll. It's a circular sinkhole measuring about 1,000 feet (300 meters) wide and more than 400 feet (124 meters) deep. It was apparently formed as part of a cave system tens of thousands of years ago, when sea levels were much lower. When the ocean's waters rose, the caves were flooded. The Great Blue Hole is part of the Belize Barrier Reef Reserve System, which UNESCO has designated a World Heritage Site.
Archaeologists and historians say the reef system provided fishing grounds for Maya communities more than a millennium ago, and later served as a haven for 17th-century pirates and buccaneers. Today, the reef is a haven for scuba divers and for marine species at risk, including West Indian manatees and green turtles.
A stereo picture from the Multi-angle Imaging Spectroradiometer aboard NASA's Terra shows an ash plume rising from Sicily's Mount Etna Volcano on Oct. 29, 2002. Wear red-blue glasses to see the 3-D effect.
You need standard red-blue glasses to experience the stereo effect, but once you put on your specs, you're in for a treat: The 3-D view makes it easier to judge the relative heights of the ash plume and the surrounding clouds.
If you don't have special glasses, you can still get a sense of the volcano's power by checking out the 2-D, natural-color view from Terra's Multi-angle Imaging Spectroradiometer. There's even a 3-second QuickTime animation that puts together a series of snaps from the satellite flyover.
This picture of Etna was the focus of today's "Where in the Cosmos" contest on the Cosmic Log Facebook page. It took a few minutes for Hong Yaw Lim, Ryan Posey and Krystyn Allison-In Oneness to identify the mystery volcano, but to reward their efforts, I'm sending them pairs of cardboard 3-D glasses, provided courtesy of Microsoft Research's WorldWide Telescope project. Press the "like" button for the Facebook page and get ready for the next 3-D glasses giveaway after the first of the year.
This is also today's offering from the Cosmic Log Space Advent Calendar, which features a different view of Earth from space every day from now until Christmas. For more visual treats, check out the links below:
The movies based on "The Lord of the Rings" and now "The Hobbit" have turned a spotlight on the dramatic landscapes of New Zealand, and this image from about 450 miles up gives you a wide-screen perspective on a modern-day Middle Earth.
The readings that went into creating the nearly cloud-free view of the Pacific island nation were captured by the Moderate Resolution Imaging Spectroradiometer aboard NASA's Terra satellite during passes in late 2002. That's just about the time that the second movie in the "Lord of the Rings" trilogy, "The Two Towers," was making a splash at the box office.
Now New Zealand filmmaker Peter Jackson has come out with the first movie of his next trilogy, based on J.R.R. Tolkien's tales of dwarfs and hobbits, a dragon and a treasure in a mythical place called Middle Earth. "The Hobbit: An Unexpected Journey" grabbed plenty of box-office treasure this weekend — $84.8 million, which translates into the best-ever three-day opening in December. (On the overall ranking for three-day openings, however, "The Hobbit" is No. 40.)
New Zealand is hoping for treasure as well: It provided more than $100 million in support for the moviemakers, and hopes to reap hundreds of millions of dollars in tourist trade sparked by the films. The country provided the backdrop for film locales ranging from the pastures of Hobbiton (near Matamata) to the volcanoes of Mordor (near Taupo). The airport in Wellington, which is New Zealand's capital as well as the home of Jackson's film operation, calls itself "the Middle of Middle Earth." Air New Zealand is now known as the "airline of Middle Earth."
From a cosmic perspective, our planet has a peaceful beauty — no matter what tumult is raging far below. That's the message NASA astronaut Ron Garan wanted to send with this picture of the northeastern United States. Today, if you could zoom in far enough on this view today, you could see the anguish left behind in the wake of Friday's horrible school shooting in Connecticut.
"When we look at Earth from space, we are faced with a sobering contradiction," Garan writes on his Google+ page. "On the one hand is the beauty of our planet, on the other is the unfortunate reality of life on our planet for many of her inhabitants. Our prayers are with the victims and families in Connecticut. #LoveConquersAll"
Garan wasn't the first human to reflect on the cosmic perspective produced by outer-space views: Astronauts and philosophers have long talked about the "Overview Effect," the sense of planetary unity that arises when you see Earth as an object suspended in space. Just this month, a group known as Planetary Collective unveiled an online video documentary exploring the phenomenon.
And then there's Carl Sagan, the famous astronomer and writer who passed away 16 years ago this month. He helped persuade NASA to turn the camera on its Voyager 1 deep-space probe back toward Earth in 1990, to capture a priceless picture of our "pale blue dot" as a speck in outer space.
"There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world," Sagan wrote. "To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known."
Forty years ago today, human beings took their last steps on the moon, and had their last look at Earth framed by the lunar horizon. There have been other pictures from the moon since then, of course, but they've all been seen secondhand, based on data sent back by robotic probes. No humans have seen an Earthrise like this one with their own eyes since Apollo 17's crew began their homeward journey on Dec. 14, 1972.
For Andrew Chaikin — author of "A Man on the Moon," the definitive history of the Apollo moon effort — the 40th anniversary of our lunar farewell is a cause for reflection.
When Chaikin was a 16-year-old outer-space fanatic, he attended Apollo 17's night launch at Kennedy Space Center, thanks to a letter he wrote to his congressman asking for a VIP pass. "It was the only part of 'Man on the Moon' that I wrote from personal experience," he told me.
Chaikin said the 12-day mission ended the Apollo program "on the highest note possible."
"By the time of Apollo 17, those guys — not just the astronauts, but the flight controllers and the planners, the whole team — they were really on top of their game," Chaikin said. "It was a spectacular mission scientifically. They landed in an absolutely spectacular place. They took some of the most memorable photographs of all the Apollo missions."
Today, Chaikin posted a video that sums up the significance of Apollo 17 as well as the importance of keeping the moon on our agenda for exploration. The five-minute clip includes an amazing view of the lunar module's ascent module rising into the sky, transmitted from a remote-control video camera that was left on the moon's surface.
Chaikin hopes that astronauts will follow through on the implied promise in the words that Apollo 17 commander Gene Cernan spoke just before climbing up from the lunar surface: "We leave as we came and, God willing, as we shall return, with peace and hope for all mankind," Cernan said.
Five days later, Cernan and his two crewmates, Harrison Schmitt and Ronald Evans, rode their command module through Earth's atmosphere and splashed down safely in the Pacific Ocean — marking the end of NASA's last round trip to the moon. Most Americans weren't even alive when that happened. So how many people living today will still be around when the next moonwalk takes place?
"I don't think we realize how exciting it's going to be when we can see the moon rise, knowing that people are living there, working to make humans a multiplanet species," Chaikin says in the video. "And when they come home, they can share with us one of the moon's most precious gifts: the sight of the earth, breathtakingly beautiful as an oasis of life in the void."
To mark the 40th anniversary of the last human footsteps on the moon, "Man on the Moon" author Andrew Chaikin looks back at Apollo 17's explorations and explains why he believes the moon is the solar system's "jewel in the crown," beckoning us to return.
Today's anniversary, recalling our species' grandest voyages, comes amid a shocking episode in Connecticut that highlights our species' violent tendencies. It was that way for the Aurora theater shootings as well, which took place on the anniversary of the Apollo 11 moon landing. Will there ever come a time when the brighter side of our nature, exemplified by the peaceful Apollo program, finally wins out over the dark side? That's one more thing to reflect on over the weekend...
Here are some of your own reflections, selected from the comments you've left over the past week on earlierinstallments of our Apollo 17 coverage:
"December of 2022 isn't that far away. At the rate we are going, and with the uncertainty and lack of focus we are experiencing regarding our manned space exploration program, I'm afraid the 50th anniversary of the Apollo 17 mission will pass without any new footprints having been made on the moon's surface by American astronauts.
"How would our lives be today if after 20 or 30 flights the Wright brothers dismantled their airplane and no one else flew for the next 50 years?
"Are we any better off now for not having continued our manned flights to the moon, and perhaps beyond?
"Will we sleep forever? America must awaken or we will find ourselves trailing behind the new leaders who will pick up the torch we long ago dropped.
"Awaken, American spirit of exploration! Arise as you once did so long ago! I miss you."
"That flight stood out, like the first flight to the moon. I can remember some of the highlights: a geologist looking at rocks, giving a reason to go to space beyond the Cold War; the 'blue marble' and a reminder that we are the one habitable planet in the solar system, so we had better keep this planet healthy. The 'Merry Merry Month of December' was funny, but at the time, also a little bit of concern: There was a worry that the breathing apparatus had a problem. What made him sing was the low gravity; he found it fun to skip on the moon because each jump covered a lot of distance, and that was visible on television (something the moonshot deniers should notice).
"I don't think of them as the last astronauts on the moon, but the most recent. It was a shock when my daughter saw videos of Neil Armstrong's moon landing in school, and I realized that another moon landing had not happened in her life. She is much older now, and my grandson has never seen a moon landing, and more and more funding is being cut, even though information from the space program is still coming to us. Look at the information from the asteroid projects and the xenon rocket. The space program is such a small part of our budget as is. It seems that every time budgets are cut, the space program suffers, schools suffer, and children have less and less to feel proud of."
"The next step for mankind is to become a celestial being. Short of that, mankind is destined to become just become one more extinct species in the vast cosmos. It is only by moving out into that vast cosmos that we see a true reflection of ourselves."
"In 1969, I sat in my sister's living room with my grandmother and watched Neil Armstrong walk on the moon. My grandmother reminisced about her life as we watched. Her father took part in the run for Indian Territory in Oklahoma. She and her siblings stayed with relatives in St. Louis while her parents built a cabin to house them. She liked to stand in the window and watch the lamplighter come around with his horse and buggy to light the gas street lights. She was educated on the farm by an old Cherokee woman who had been to finishing school in Europe, but forced on the long 'trail of tears' march to Indian Territory in 1838-39. She lost all of her family on the way. My great-grandfather eventually sold the farm and bought a store in town. Grandma married a farmer and moved back to Indian Territory, where she raised nine children without the benefit of electricity. All their water was carried from the creek, light was provided by kerosene lanterns and homemade candles. My children, grandchildren and great-grandchildren can never fully appreciate the grandeur of the moment as seen through my grandmother's eyes. It was an epic accomplishment and I have no doubt that we will return — to the moon and to many other worlds."
"We truly are a great nation at times — if only we'd remember that."
"My fear is that, in this day and age, America will go to the moon (and/or Mars) and treat it in the usual, selfish, utilitarian way. We have already screwed this planet up. Now they are considering going elsewhere. Of course, once we're there, we'll screw that up too. Here's an 'out-of-this-world' thought: Focus on population control and conservation to limit how badly we're screwing up the one and only world we're ever going to have."
"Planting a radio telescope on the far side of the moon, shielded from the radio noise generated by all of our technology, might well provide the kind of scientific bonanza that Hubble has created.
"That's what's lacking in most the moon mission proposals: the promise of being able to carry out some real science. Most of the proponents of a lunar return offer little more than, 'It would be neat to go back and look around some more.' That's a little vague, given the cost and danger involved."
Pb in CA:
"Somebody explain to me why going to the surface of the moon is valuable. There is nothing there of any value. OK, I've heard the idea of building a radio receiver on the far side. But, it would be more cost-effective to build a very-long-baseline radio receiver system using a fleet of satellites that stay in low-moon orbit, and half the time are shielded from earth radio noise.
"If we are willing to accept the fact that robots are much better adapted to carrying out missions in space, then we can have a sustainable, affordable space exploration program. The Augustine Commission got it right in this regard. Personally, I have no problem in thinking of robots as extensions of humans, and saying 'we are exploring the surface of Mars' currently with Curiosity.
"Here are the advantages of robots vs. humans on the moon: - Robots can stay indefinitely - no return trip to Earth - Energy supply is sun power - no need to take air, food and water - Very close communication to humans back on Earth - 2.5-second round trip - Cost of a mission is 1:2000 compared to sending humans
"What is gained by sending humans?"
"I can't believe that we are trillions of dollars in debt and the government is seriously considering cutting health care for the elderly — but we can even consider borrowing money to go to the moon. Clean up the mess, then spend money on 'toys.' America can't afford this right now."
"Yes, we're in bad shape here on Earth. In many ways. But we were born to look out and dream ... to explore. We went to the moon ... we have rovers on Mars, [including] one working years after it was supposed to die. Voyager 1 is reaching the end of our solar system, and will soon be beyond it — our first UFO. If we don't go back to the moon ... go to Mars ... [and] go beyond that someday, when we solve our petty differences here on Earth and put our minds to developing the mechanism to go outward into the unknown, what do we have to look forward to? What do young people have to dream about? When I stand outside on a clear night and look out at all the stars, I often wonder if anyone is looking back. Looking back and dreaming of places unknown and things never before seen, just as I am."
In addition to marking the 40th anniversary of Apollo 17's lunar departure, this Earthrise serves as today's offering for the Cosmic Log Space Advent Calendar, which features views of Earth from outer space on a daily basis from now until Christmas. Check out these other holiday goodies: