Scientists Observing Neptune Say the Planet Is Getting Colder
2022-04-18
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1Researchers say new observations of Neptune suggest the planet is getting colder.
2An international team of astronomers used ground-based telescopes in Hawaii and Chile to estimate Neptune's atmospheric temperatures.
3The team examined nearly 100 infrared images captured by the telescopes from 2003 to 2020.
4The data showed that Neptune experienced a surprising drop in atmospheric temperatures over the past 17 years.
5Considered an "ice giant," Neptune is the outermost planet in our solar system.
6It is about four times wider than Earth.
7Neptune orbits more than 30 times as far away from the sun as Earth does.
8This means it needs about 165 Earth years to complete a single orbit around the sun.
9Neptune is among the least explored planets.
10The American space agency NASA's Voyager 2 is the only spacecraft to have passed close to Neptune, which it did in 1989.
11The latest examinations of Neptune's atmospheric temperatures are the most detailed ever collected.
12The team recently reported its findings in the publication Planetary Science Journal.
13The researchers centered on Neptune's stratosphere, an upper part of the atmosphere just above the planet's weather layer.
14Neptune's stratosphere temperature fell to minus 117 Celsius, a drop of eight degrees, during the 17-year period.
15By comparison, temperatures in Neptune's troposphere - the even-colder weather layer - showed no major changes.
16The troposphere reached temperatures as low as minus 223 Celsius.
17"This change was unexpected," said Michael Roman of the stratospheric readings.
18He is a postdoctoral researcher at the University of Leicester in Britain and the lead writer of the study.
19"I think Neptune is very intriguing to many of us because we still know so little about it," Roman added.
20He noted that the Neptune observations led researchers to believe that conditions on the planet were more complex than first thought.
21Roman said the finding "seems to be a general lesson that nature teaches scientists again and again."
22The astronomers collected Neptune temperatures using cameras equipped to measure infrared light from space objects, the European Southern Observatory (ESO) said in a statement.
23Most of the team's observations were made with the ESO's Very Large Telescope, which is based in northern Chile.
24The temperature changed over time and unevenly.
25 The area of the planet known as the southern tropics cooled, then warmed, then cooled again.
26In the middle areas, temperatures remained similar before starting to fall over time.
27Temperatures at the south pole showed only minor drops during most of the period, the researchers reported.
28But then, the area warmed quickly and sharply.
29From 2018 to 2020, the temperature at the south pole rose by 11 degrees.
30"I suspect the overall temperature drop may most likely be due to changes in the atmospheric chemistry, which responds to changing seasonal sunlight," Roman said.
31Neptune may offer lessons about planets beyond our solar system, called exoplanets, said study co-author Glenn Orton.
32He is a planetary scientist at NASA's Jet Propulsion Laboratory in California.
33"The close relationship that Neptune may share with a large segment of the population of exoplanets means that it may be 'an exoplanet in our backyard,'" Orton said.
34He added that Neptune could become "a model for the things we might expect to see in the meteorology" of exoplanets studied in the future.
35I'm Bryan Lynn.
1Researchers say new observations of Neptune suggest the planet is getting colder. 2An international team of astronomers used ground-based telescopes in Hawaii and Chile to estimate Neptune's atmospheric temperatures. The team examined nearly 100 infrared images captured by the telescopes from 2003 to 2020. The data showed that Neptune experienced a surprising drop in atmospheric temperatures over the past 17 years. 3Considered an "ice giant," Neptune is the outermost planet in our solar system. It is about four times wider than Earth. Neptune orbits more than 30 times as far away from the sun as Earth does. This means it needs about 165 Earth years to complete a single orbit around the sun. 4Neptune is among the least explored planets. The American space agency NASA's Voyager 2 is the only spacecraft to have passed close to Neptune, which it did in 1989. 5The latest examinations of Neptune's atmospheric temperatures are the most detailed ever collected. The team recently reported its findings in the publication Planetary Science Journal. 6The researchers centered on Neptune's stratosphere, an upper part of the atmosphere just above the planet's weather layer. Neptune's stratosphere temperature fell to minus 117 Celsius, a drop of eight degrees, during the 17-year period. By comparison, temperatures in Neptune's troposphere - the even-colder weather layer - showed no major changes. The troposphere reached temperatures as low as minus 223 Celsius. 7"This change was unexpected," said Michael Roman of the stratospheric readings. He is a postdoctoral researcher at the University of Leicester in Britain and the lead writer of the study. "I think Neptune is very intriguing to many of us because we still know so little about it," Roman added. 8He noted that the Neptune observations led researchers to believe that conditions on the planet were more complex than first thought. Roman said the finding "seems to be a general lesson that nature teaches scientists again and again." 9The astronomers collected Neptune temperatures using cameras equipped to measure infrared light from space objects, the European Southern Observatory (ESO) said in a statement. Most of the team's observations were made with the ESO's Very Large Telescope, which is based in northern Chile. 10The temperature changed over time and unevenly. The area of the planet known as the southern tropics cooled, then warmed, then cooled again. In the middle areas, temperatures remained similar before starting to fall over time. Temperatures at the south pole showed only minor drops during most of the period, the researchers reported. But then, the area warmed quickly and sharply. From 2018 to 2020, the temperature at the south pole rose by 11 degrees. 11"I suspect the overall temperature drop may most likely be due to changes in the atmospheric chemistry, which responds to changing seasonal sunlight," Roman said. 12Neptune may offer lessons about planets beyond our solar system, called exoplanets, said study co-author Glenn Orton. He is a planetary scientist at NASA's Jet Propulsion Laboratory in California. 13"The close relationship that Neptune may share with a large segment of the population of exoplanets means that it may be 'an exoplanet in our backyard,'" Orton said. He added that Neptune could become "a model for the things we might expect to see in the meteorology" of exoplanets studied in the future. 14I'm Bryan Lynn. 15Reuters and the European Southern Observatory reported on this story. Bryan Lynn adapted the reports for VOA Learning English. 16We want to hear from you. Write to us in the Comments section, and visit our Facebook page. 17_________________________________________________________________ 18Words in This Story 19giant - n. extremely large 20layer - n. the amount of a substance covering a surface 21intriguing - adj. very interesting 22tropics - n. the hottest part of the world 23meteorology - n. the science of planetary atmosphere and weather 24segment - n. one of the parts something can be divided into