PHYS 1412: Cosmic Collisions

Changed my mind. Let's do the "Cosmic Collisions" part of the CD.

Just above the end of the Big Dipper is M82, an irregular galaxy. Its irregular features are caused by spiral galaxy M81's flyby in the past. The flyby created unusual gravitational forces.

M82 is one of the brightest infrared objects in the sky. (Because of the excess of warm gas and dust in its core, from M81).

Centaurus A has a big dust lane. In its case a smaller galaxy probably actually collided with it. The core may have a large black hole. (It has a big jet like M87.

M51 (Whirlpool Galaxy) is actually two galaxies. We can tell they are interacting because:

• the obvious stream of gas between them
• the larger one's spiral arm has been pulled out of shape by this gas
• the smaller galaxy has a distorted shape
• the smaller galaxy looks more like a galactic core with its arms missing
• there are dust lanes between the two
• there is gas and dust moving perpendicular to the smaller galaxy's long axis

Examples of other galactic collisions include the Antennae Galaxy and the Cartwheel Galaxy. Oo, the Cartwheel is pretty. Prettier than a barred spiral.