Spaceflight Now Home

Spaceflight Now +

Premium video content for our Spaceflight Now Plus subscribers.

Cassini preview
The Cassini spacecraft's arrival at Saturn is previewed in this detailed news conference from NASA Headquarters on June 3. (50min 01sec file)
 Play video

Relive Cassini's launch
An Air Force Titan 4B rocket launches NASA's Cassini spacecraft at 4:43 a.m. October 15, 1997 from Cape Canaveral, Florida. (5min 15sec file)
 Play video

Exploring the hills
"A brand new mission" is beginning for the Mars Exploration Rover Spirit as it nears the Columbia Hills as described in this presentation by science team member James Rice. (5min 57sec file)
 Play video

Exploring Endurance
New pictures from the Mars rover Opportunity as it drives around the rim of Endurance Crater are presented with narration by science team member Wendy Calvin. (5min 25sec file)
 Play video

Mars rover update
Mission officials and scientists discuss the condition and progress of Mars rovers Spirit and Opportunity plus the latest science news in this briefing from June 2. (40min 55sec file)
 Play video

Options to save Hubble
NASA Administrator Sean O'Keefe announces plans to examine a robotic servicing mission to the Hubble Space Telescope. (33min 51sec file)
 Play video

Station supply ship
Ride along with the Progress 14P resupply ship as it makes the final approach and docking to the International Space Station on May 27 as seen by a camera mounted on the craft's nose. (9min 02sec file)
 Play video

Results from Spitzer
Scientists present new discoveries from the Spitzer Space Telescope, including their findings of raw ingredients for life detected around young stars. (53min 03sec file)
 Play video

Spacewalk previewed
The Expedition 9 crew describes their upcoming spacewalk in Russian spacesuits, life aboard the space station and the view of Earth in this interview with Bill Harwood of CBS News. (20min 19sec file)
 Play video

Progress undocking
The Progress 13P cargo ship departs the International Space Station on May 24 carrying trash and unneeded items to burn up in the atmosphere. (2min 56sec file)
 Play video

AP interviews the crew
The Associated Press interviews the two-man Expedition 9 crew living aboard the International Space Station on May 24. (9min 36sec file)
 Play video
 More clips

Become a subscriber
More video


Sign up for our NewsAlert service and have the latest news in astronomy and space e-mailed direct to your desktop.

Enter your e-mail address:

Privacy note: your e-mail address will not be used for any other purpose.

Pinwheel Galaxy's hidden wonders revealed
Posted: June 4, 2004

Like nosy neighbors, astronomers are spying on one of the nearest galaxies to our Milky Way. In studying the Pinwheel Galaxy, also known as Messier 33 (M33), they seek not malicious gossip but new knowledge as they search for clues to how galaxies like our own are born, live, and die.

At the 204th meeting of the American Astronomical Society in Denver, Colorado, astronomers from the University of Minnesota, the Harvard-Smithsonian Center for Astrophysics (CfA), and the University of Arizona unveiled new infrared images of M33 taken by NASA's Spitzer Space Telescope. The photos reveal features of the galaxy never before visible.

This Spitzer Space Telescope image of the Pinwheel Galaxy (M33) reveals a multitude of dusty red spiral arms studded with bright knots marking star formation regions. By studying this nearby galaxy in detail, astronomers can see "the Universe in a nutshell." Credit: E. Polomski et al. (University of Minnesota), G. Fazio et al. (SAO)
About 50,000 light-years across, the spiral galaxy M33 is half the diameter of the Milky Way. It lies 3 million light-years from the Milky Way, which places it among the Local Group of galaxies. Its nearness and viewing angle give astronomers an excellent opportunity to study M33's physical and chemical processes.

"With the Andromeda Galaxy, it's one of the two nearest large spiral galaxies comparable to the Milky Way. Since it's so close, we can get a nice panoramic view. It's a great object for detailed study," said Smithsonian astronomer Steven Willner (CfA).

"M33 is a gigantic laboratory where you can watch dust being created in novae and supernovae, being distributed in the winds of giant stars, and being reborn in new stars," said University of Minnesota researcher and lead author Elisha Polomski. By studying M33, "you can see the Universe in a nutshell."

Because it operates at infrared wavelengths, the Spitzer Space Telescope detects details hidden to the human eye and to telescopes that operate in visible light. Spitzer collects light at wavelengths measured in microns-millionths of a meter. The new pictures were taken in light at wavelengths ranging from 3.5 to 24 microns.

"At 3.5 microns, we see stars," said University of Minnesota astronomy professor Robert Gehrz, a member of the M33 observation team. "At eight microns, we see warm dust that's about 130 degrees Fahrenheit. At 24 microns, we're picking up cool dust that's between minus 100 and minus 190 degrees Fahrenheit." Spitzer's cameras also operate at 70 and 160 microns.

Observations of M33's cool components are expected to reveal much about the "metabolism" of galaxies. A galaxy is akin to a living body, in which food substances are broken down to build the body, and the waste and decomposition products of a body are recycled to feed new life. For example, the iron in Earth's core was forged in the bellies of large, luminous stars, and the heavier elements-all the way to uranium, the heaviest naturally occurring element-were created in supernova explosions. The deaths of those stars sprayed interstellar space with dust and gas, some of which clumped together in a disk that coalesced to form the sun and its planets.

The Spitzer team will examine the Pinwheel Galaxy in detail for the next two and a half years, studying the processes that circulate energy and chemical elements through the galaxy to build up, destroy, and recycle the building blocks of stars and planets. The researchers expect to identify new star-forming regions, red giant stars, novae and supernovae, thereby mapping out the evolutionary process of stars in M33 and comparing it to the process in our own Galaxy.

The NASA Jet Propulsion Laboratory (JPL) manages the Spitzer Space Telescope mission for NASA's Office of Space Science, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. JPL is a division of Caltech.

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.