Night Flight to the Stars

Activity 4E: Mapping a Galaxy

The KAO end its night-time observing run with observations of neighboring spiral galaxy called M33, at a distance of 2.6 million light years.

Located in the constellation Triangulum, M33 is a spiral galaxy belonging to our Local Group of galaxies (which also includes the Milky Way and the Great Galaxy in Andromeda, M31). M33 appears nearly face-on, but is actually titled about 35° towards our line of sight. M33 is 50,000 light years across--making it about half the size of the Milky Way.

This is M33 in visible light (above right). Trace the spiral arms extending from the galaxy's core. Notice the bright clouds of dust and gas as well as the dark dust clouds making lanes through the arms. These are similar to features in the Milkey Way Galaxy. The brightest cloud in M33 is 11 arc minutes from the nucleus of the galaxy.

The image to the right was captured by the IRAS infrared satellite at a wavelength of 60 microns. The image has been processed so that the brightest areas in IR appear lightest.

Compare the two photographs. Identify the areas on the visible light photograph above that are also bright at infrared wavelengths. Find any areas that are bright in IR and not bright in visible light.

The white square in the corner of the photo above is the area of the KAO telescope field at 60 microns. Based on the IR data to the right, pick areas you would observe with the KAO. Record observations made by KAO astronomers during their flight.

This page was created by Daniel Helfman, a junior at Mission San Jose High School in Fremont, CA.

| LFS Home | Give Us Feedback! | LFS Overview | Search Passport to Knowledge |Passport Home |