最近一個週期中,M82的重力增強了M81周圍密度波的脈動,導致M81的旋臂更濃密。
M82, as this irregular galaxy is also known, was stirred up by a recent pass near large spiral galaxy M81.
右邊被藍*旋臂環繞的是旋渦星系M81。
Last go-round, M82's gravity likely raised density waves rippling around M81, resulting in the richness of M81's spiral arms.