Astronomy Picture of the Day: NGC 4698: a quiet galaxy with a rebellious heart!

 

#NASA, #Space, #astronomy, #διάστημα

From a distance, NGC 4698 looks like a galaxy that has already made peace with itself. About 55 million light-years away, on the edge of the Virgo Cluster, it appears calm and collected: a compact bulge, tightly wound or barely visible arms, and a disk some 80,000–85,000 light-years across. No fireworks. No obvious wreckage. Just a tidy early-type spiral that seems to have settled down. Then you measure how it turns. The outer disk rotates one way. The inner bulge and nuclear disk rotate the other—almost at right angles, as if the galaxy’s heart refuses to follow the rest of its body. That is not a trick of the light. It is leftover angular momentum: the mark of gas or a smaller galaxy that later settled onto a different plane of an already existing bulge, leaving two motions locked inside one object. The smooth, almost lenticular look is a disguise. Beneath the even glow sits the memory of an ancient merger or accretion. An old collision is still turning in opposite directions. NGC 4698: a quiet galaxy with a rebellious heart.