ngc-4647

(via APOD: 2012 September 14 - Elliptical M60, Spiral NGC 4647)

The Virgo Cluster has a lot of galaxies. A lot.

No, I don’t think you understand. The Milky Way is part of the Local Group. Our cluster contains us, Andromeda, and M33 as the major galaxies, all three spirals, and then about 40-some dwarf ellipticals and irregulars all gravitationally bound.

The Virgo Cluster has 3,500 galaxies. Are we in any way surprised that the local supercluster of which we are a part is known as the Virgo Supercluster? No. So, with that many galaxies, we probably shouldn’t be too surprised to see massive M60, a 120,000 light-year diameter elliptical galaxy, and NGC 4647, a 90,000 light-year diameter spiral much like our own galaxy, moving around the near edge of the Virgo Cluster on a bit of a collision course.

Should be interesting, as there’s not much more than old stars in an elliptical galaxy, but a spiral has a bunch of gas and dust that can be warped around by a gravitational encounter. That can sometimes set off a bunch of star formation (remember what we keep seeing inside of dense nebulae).

Credit: NASAESAHubble Heritage Team (STScI/AURA)

Elliptical M60, Spiral NGC 4647 
Credit: NASAESAHubble Heritage Team (STScI/AURA)

Explanation: Giant elliptical galaxy M60 and spiral galaxy NGC 4647 do look like an odd couple in this sharp cosmic portrait from the Hubble Space Telescope. But they are found in a region of space where galaxies tend to gather, on the eastern side of the nearby Virgo Galaxy Cluster. About 54 million light-years distant, bright M60's simpler egg-like shape is created by its randomly swarming older stars, while NGC 4647’s young blue stars, gas and dust are organized into winding arms rotating in a flattened disk. Spiral NGC 4647 is estimated to be more distant than M60, some 63 million light-years away. Also known as Arp 116, the pair of galaxies may be on the verge of a significant gravitational encounter, though. M60 (aka NGC 4649) is about 120,000 light-years across. The smaller NGC 4647 spans around 90,000 light-years, about the size of our own Milky Way.

Elliptical M60, Spiral NGC 4647 

Credit: NASA, ESA, Hubble Heritage Team (STScI/AURA)

Explanation: Giant elliptical galaxy M60 and spiral galaxy NGC 4647 do look like an odd couple in this sharp cosmic portrait from the Hubble Space Telescope. But they are found in a region of space where galaxies tend to gather, on the eastern side of the nearby Virgo Galaxy Cluster. About 54 million light-years distant, bright M60’s simpler egg-like shape is created by its randomly swarming older stars, while NGC 4647’s young blue stars, gas and dust are organized into winding arms rotating in a flattened disk. Spiral NGC 4647 is estimated to be more distant than M60, some 63 million light-years away. Also known as Arp 116, the pair of galaxies may be on the verge of a significant gravitational encounter, though. M60 (aka NGC 4649) is about 120,000 light-years across. The smaller NGC 4647 spans around 90,000 light-years, about the size of our own Milky Way.