Getting a Black Eye

The results:

Does yours look like this?

The dark patch is revealed as a mixture of dust, gas and young stars.

The wall of dust and gas that gives M64 its black eye has been created by an extraordinary thing.

Galaxies usually revolve in one direction. This image helped to show that whilst the stars and material in the main part of the galaxy revolves one way (clockwise as seen in this image) the outer gas cloud revolves the opposite way. The cosmic ‘friction’ where the two meet has piled the dust and gas up into a relatively concentrated wall creating a super factory for star formation. The young, hot, blue stars give off lots of ultraviolet light that makes the clouds of hydrogen fluoresce in vivid pink. So, M64 has not only got a black eye but a bloodshot one too!

So what lumped one on M64? Stephen Smartt thinks it was another, smaller galaxy. But the little galaxy came of worse; M64’s gravity tore it to bits. All that is left is the ghostly shell of gas, revolving the wrong way.

Stephen says “I'm hoping one of those bright dots (the most massive stars in the galaxy) will one day explode as a supernova. Then I can estimate it's colour, temperature, radius and mass. Typical supernova rates are 1 per 100 years (approx - uncertain by factor ~2), but if you have 100 galaxies then of course its up to 1 per year. So this galaxy was part of a large programme to image hundreds and then wait. I identified one recently - see "Massive old star reveals secrets on deathbed" link on my homepage. Now I just waiting for another !”