The stability of the sun's light has probably nourished terrestrial life, but "superflares"—outbursts 10 to 10,000 times stronger than any known solar flare—can arise from stars as warm and massive as our own. Just one superflare could damage the ozone layer and kill off species on an orbiting planet. Now, thanks to 4 months of observations of 83,000 suns by NASA's Kepler spacecraft, astronomers have discovered that 148 of these stars launched a total of 365 superflares. Most of these feisty stars spin fast, intensifying magnetic fields that spawn spots and flares, but one star in six rotates slowly, like the sun. Every superflare-spewing star has spots so huge they cause the starlight to vary as the star turns, the team reports online today in Nature. Thankfully, spots this large don't appear on the sun, suggesting that our star (shown here) is too tame to unleash a superflare that would fry us all.

 很可能是太陽光線的穩(wěn)定性滋養(yǎng)了地球上的生命。但是，超級耀斑的爆發(fā)比任何已知的太陽耀斑要強(qiáng)10倍至10,000倍，這種耀斑可能會產(chǎn)生于跟太陽一樣溫暖、一樣龐大的恒星上。僅僅爆發(fā)一個(gè)超級耀斑可能就會摧毀臭氧層，將周圍行星上的物種置于死地。目前，通過NASA的開普勒太空船對83,000顆恒星進(jìn)行了4個(gè)月的觀察，天文學(xué)家們發(fā)現(xiàn)其中148顆恒星共爆發(fā)了365個(gè)超級耀斑。多數(shù)易爆發(fā)超級耀斑的恒星旋轉(zhuǎn)很快，加強(qiáng)了引發(fā)黑子和耀斑的磁場，但是有六分之一的恒星跟太陽似的，旋轉(zhuǎn)較慢。今天，研究小組在《自然》雜志在線版上報(bào)道說：每個(gè)噴射超級耀斑的恒星都有大片的黑子，黑子區(qū)如此巨大，以至于隨著恒星的旋轉(zhuǎn)會引起恒星光線發(fā)生變化。謝天謝地，這么大片的黑子沒有出現(xiàn)在太陽上，這說明我們的太陽（見上圖）還是非常溫順的，不會釋放那種會將我們烤焦的超級耀斑。