When two galaxies collide, the stars do not generally run into eachother, but the gas clouds do collide, triggeering a burst of new star formation. a) Estimate the probability that our Sun would collide with another star in the Andromeda galaxy if a collision between the Milky Way and Andromeda occured. Assume that each galaxy has 100 billion stars exactly like the sun, spread evenly over a circular disk with a radius of 100,000 lightyears. (Hint: first calculate total area of 100 billion circles with the radius of the Sun and then compare that to total area to the area of the Galatic disk) b) Estimate the probability of a collision between a gas cloud in our galaxy and one in the Andromeda galaxy. Assume that each galaxy has 100,000 clouds of warm hydrogen gas, each with a radius of 300 lightyears, spread evenly over the same disk. Use the same method as part A.

When two galaxies collide, the stars do not generally run into eachother, but the gas clouds do collide, triggeering a burst of new star formation. a) Estimate the probability that our Sun would collide with another star in the Andromeda galaxy if a collision between the Milky Way and Andromeda occured. Assume that each galaxy has 100 billion stars exactly like the sun, spread evenly over a circular disk with a radius of 100,000 lightyears. (Hint: first calculate total area of 100 billion circles with the radius of the Sun and then compare that to total area to the area of the Galatic disk) b) Estimate the probability of a collision between a gas cloud in our galaxy and one in the Andromeda galaxy. Assume that each galaxy has 100,000 clouds of warm hydrogen gas, each with a radius of 300 lightyears, spread evenly over the same disk. Use the same method as part A.