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a witch’s cauldron. 🧙 gastrointestinal reflux. 🤢a kale smoothie. 🥬 the eerie, green swirls of this satellite image may conjure up many mental pictures—except what it actually is. on april 12, 2019, the operational land imager on landsat 8 acquired this image of lake khanka. |
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these images show puzhal lake, the primary rain-fed reservoir in chennai, tamil nadu. they were acquired on may 31, 2018 (full), and june 19, 2019 (empty), by the operational land imageron landsat 8. puzhal lake (also known as red hills lake) is one of four main reservoirs that serves the city of chennai. in total, the four reservoirs were only at 0.2 percent capacity, as reported on june 21, 2019. |
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this photo shows the eagle lunar module as it carried neil armstrong and buzz aldrin to a rendezvous with the columbiacommand and service modules after a 22-hour stay on the moon. shot by apollo 11 astronaut michael collins, the image was acquired just before docking at 21:34:00 universal time (5:34 p.m. u.s. eastern daylight time) on july 21. collins was looking west as earth rose above the horizon. the dark-colored mare in the background is smyth’s sea (85° east longitude, 2° south latitude on the moon). |
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how to answer. you can use a few words or several paragraphs. you might simply tell us the location. or you can dig deeper and explain what satellite and instrument produced the image, what spectral bands were used to create it, or what is compelling about some obscure feature in the image. if you think something is interesting or noteworthy, tell us about it. |
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this image shows the bloom on july 30, 2019, as observed by the operational land imager on the landsat 8 satellite. green patches show where the bloom was most dense and where toxicity levels were unsafe for recreational activities. around the time of this image, the bloom covered about 300 square miles of lake erie’s surface, according to news reports; by august 13, the algae had spread across 620 square miles. |
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wave clouds would have formed on the leeward side all of the islands in the image, even though the patterns were not easily visible behind all of them. “for the three northern islands, the wakes are there, but there is another cloud layer on top, partially ruining the view,” said wind. “clouds have a habit of being multi-layered.” |
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on february 25, 2020, the advanced spaceborne thermal emission and reflection radiometer (aster) on nasa’s terra satellite acquired this false-color image of a volcanic plume venting from the summit crater. the image combines infrared, red, and green wavelengths such that the surrounding vegetation appears red. |
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but now, the cascade has disappeared. it stopped flowing on february 2, 2020. the images above show the falls and the surrounding river basin while water still flowed on august 4, 2014 (left) and after it stopped on march 15, 2020 (right). these images were acquired by the operational land imager (oli) on landsat 8. the image below shows a photograph of the falls on november 28, 2012. |
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this view of the region pictured above was acquired august 7, 2012, by the advanced spaceborne thermal emission and reflection radiometer (aster) on nasa's terra satellite. |
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the reflection of the moon on the sea surface—moonglint—reveals highly complex patterns. the strongest reflection is near the center of the moon’s disc, which brightens the water around the island of #elba. in these complex patterns, the dark areas of the sea surface can sometimes make islands (such as #montecristo and #pianosa) harder to see. (a similar phenomenon happens in the daylight, as shown in sunglint images of lakes in brazil and aquaculture in the nile delta.) the reflection off sea surfaces captures many different natural processes, but also some made by humans. north of elba, waves trailing behind ships make the classic v-shaped pattern. the meandering line coming off montecristo island is an “island wake,” a result of alternating vortices of wind that develop on the downwind side of the island. this wake is the strongest evidence that a northeast wind was blowing (right to left in this image) on the night of the photo. a shorter, meandering wind pattern is being shed off punta ala on the mainland. smoother surfaces, protected from wind, are usually brighter because they are better mirror for moonlight. |
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as an equatorial country, indonesia is often obscured by cloud cover. an astronaut aboard the international space station recently seized the opportunity of a relatively storm-free day to photograph nearly half the length of indonesia’s main island chain. using a short lens and looking to the horizon for a panoramic effect, the astronaut captured this vast view that includes both clear skies and a murky, region-wide smoke pall. the smoke comes from fires caused by lightning strikes and by forest clearing by humans in indonesia and northern australia. |
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on march 17, 2020, the moderate resolution imaging spectroradiometer (modis) on nasa’s terra satellite acquired this natural-color image of lake beloye in russia’s vologda region. it stands out in part because its water is shallowly spread across more than 1,000 square kilometers (400 square miles)—larger than the average lake area in this part of northwest russia. |
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the susquehanna river cuts through the folds of the valley-and-ridge province of the appalachian mountains in this photograph taken by an astronaut onboard the international space station on december 24, 2019. harrisburg, pennsylvania, and a few smaller towns stand along the banks of the river. |
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the moderate resolution imaging spectroradiometer (modis) on nasa’s aqua satellite acquired this image of colorful surface waters off of mauritania on may 5, 2020. scrolling through satellite images of the area reveals that there is nothing particularly unique about the may 5 image; the tongue of green water is present constantly throughout the year. |
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different climate zones are broadly visible in the image. on the southern coast facing the gulf of mexico, the climate is tropical and wet. forests and coastal plains appear with a slight green tone. looking inland, clouds tend to form around the mountains and often shroud tall volcanic peaks. the lighter toned tan-brown terrain of the interior is mostly desert country that stretches north across the u.s.-mexico border. |