Hubble just released a new picture of NGC 4698. Look closely and one part of it turns the wrong way — and astronomers think they know why.
NGC 4698 sits about 55 million light-years away in Virgo, inside a crowd of more than 1,000 galaxies known as the Virgo Cluster.
Here is the odd part. The stars and gas nearest the center rotate perpendicular to the rest of the disk — two spins in one galaxy.
A normal spiral like Messier 74 turns as one flat wheel. Core, arms and gas all share a single plane and a single direction.
Every spiral has a bulge of old stars at its heart, like the Sombrero Galaxy's here. NGC 4698's is tipped 90 degrees to its disk.
NASA's leading explanation is a minor merger. Gas pulled in from outside settled into a fresh disk at an angle to the old one.
A stream of hydrogen trails off one side of NGC 4698. Other cluster galaxies, like IC 3476 here, are losing gas too.
The new picture comes from the MAUVE-HST team's Hubble program on Virgo. Hubble has photographed neighbors like Messier 90 too.
At the center of NGC 4698 sits a supermassive black hole millions of times the Sun's mass, and it is actively pulling in material.
Hubble launched in April 1990. Three and a half decades on it is still catching things nobody expected, like a galaxy at odds with itself.
Odd galaxies show how a crowded cluster reshapes its members, and when a galaxy finally stops building new stars.