Study Suggests Sun Less Active than Similar Stars
2020-05-06
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1A new study suggests the sun appears to experience far fewer changes in brightness and intensity than other stars like it.
2Researchers reported last week on their examination of 369 stars.
3They compared each one to the sun in terms of surface temperature, size and rotation.
4They found that on average, the other stars had five times more brightness variability than our sun.
5A report on the study and its findings was published in Science magazine.
6The lead author was Timo Reinhold, an astronomer with the Max Planck Institute for Solar System Research in Germany.
7He told the Reuters news agency that the variability in brightness results from dark spots on the surface of the star moving in and out of view.
8"A direct measure of solar activity is the number of sunspots on the surface," Reinhold said.
9"Finding such stars with very similar parameters as our sun but being five times more variable was surprising."
10The sun - made up mainly of hydrogen and helium - is an average-sized star that formed more than 4.5 billion years ago.
11It stretches about 1.4 million kilometers across and has a surface temperature of 5,500 degrees Celsius.
12The researchers compared scientific data on the similar stars to historical records of the sun's activity.
13The records included about 400 years of observational data on sunspots.
14The researchers also studied about 9,000 years of data based on chemical element variants in tree rings and ice buildup tied to solar activity.
15These records show the sun has not been much more active than it is now.
16The researchers said increased magnetic activity related to sunspots can lead to electromagnetic events that affect Earth.
17For example, large releases of plasma - a collection of charged particles - from outer areas of the sun's atmosphere could cause problems for satellites and other communications equipment.
18Other electromagnetic activities could also result in such difficulties.
19The discovery that the sun does not experience as many changes as other stars may be good news for life on Earth.
20A much more active sun might have had more major effects on Earth's geology and ancient climate.
21"A 'too active' star would definitively change the conditions for life on the planet, so living with a quite boring star is not the worst option," Reinhold said.
22The findings, he noted, do not rule out the possibility that the sun may be in a quiet period and could become more variable in the future.
23However, the researchers say there are no signs that solar activity will be increasing any time soon.
24"For the last decade, the sun has been showing itself to be rather weakly active, even by its own low standards," they said in a statement.
25"Predictions of activity for the next 11 years indicate that this will not change soon."
26I'm Bryan Lynn.
1A new study suggests the sun appears to experience far fewer changes in brightness and intensity than other stars like it. 2Researchers reported last week on their examination of 369 stars. They compared each one to the sun in terms of surface temperature, size and rotation. They found that on average, the other stars had five times more brightness variability than our sun. 3A report on the study and its findings was published in Science magazine. 4The lead author was Timo Reinhold, an astronomer with the Max Planck Institute for Solar System Research in Germany. He told the Reuters news agency that the variability in brightness results from dark spots on the surface of the star moving in and out of view. 5"A direct measure of solar activity is the number of sunspots on the surface," Reinhold said. "Finding such stars with very similar parameters as our sun but being five times more variable was surprising." 6The sun - made up mainly of hydrogen and helium - is an average-sized star that formed more than 4.5 billion years ago. It stretches about 1.4 million kilometers across and has a surface temperature of 5,500 degrees Celsius. 7The researchers compared scientific data on the similar stars to historical records of the sun's activity. The records included about 400 years of observational data on sunspots. The researchers also studied about 9,000 years of data based on chemical element variants in tree rings and ice buildup tied to solar activity. These records show the sun has not been much more active than it is now. 8The researchers said increased magnetic activity related to sunspots can lead to electromagnetic events that affect Earth. For example, large releases of plasma - a collection of charged particles - from outer areas of the sun's atmosphere could cause problems for satellites and other communications equipment. Other electromagnetic activities could also result in such difficulties. 9The discovery that the sun does not experience as many changes as other stars may be good news for life on Earth. 10A much more active sun might have had more major effects on Earth's geology and ancient climate. "A 'too active' star would definitively change the conditions for life on the planet, so living with a quite boring star is not the worst option," Reinhold said. 11The findings, he noted, do not rule out the possibility that the sun may be in a quiet period and could become more variable in the future. 12However, the researchers say there are no signs that solar activity will be increasing any time soon. 13"For the last decade, the sun has been showing itself to be rather weakly active, even by its own low standards," they said in a statement. "Predictions of activity for the next 11 years indicate that this will not change soon." 14I'm Bryan Lynn. 15Reuters reported on this story. Bryan Lynn adapted the report for VOA Learning English, with additional information from the Max Planck Institute for Solar System Research. George Grow was the editor. 16We want to hear from you. Write to us in the Comments section, and visit our Facebook page. 17________________________________________________________________ 18Words in This Story 19rotation - n. turning in a circular direction 20variability - n. the state of changing often 21author - n. a writer of a book or report 22view - n. the ability to see something or to be seen 23parameter - n. a limit that controls the way something is done 24geology - n. the study of rocks and soil and the physical structure of the Earth 25boring - adj. not interesting 26option - n. a choice or possibility 27decade - n. a period of 10 years 28standard - n. a level of quality or behavior