Imagine Magazine - Johns Hopkins - September/October 2011 - (Page 22)

This Green Ring Nebula glows in infrared colors invisible to our eyes, but is brilliantly detailed in this image from NASA’s Spitzer Space Telescope. GALEX’s UV sky survey revealed a previously “hidden” comet-like tail (top) on an old red giant star (bottom). NA SA /JP -C AL TE CH Surveying the Sky Distant, young stars emit most of their light in the ultraviolet spectrum. The Galaxy Evolution Explorer satellite (GALEX) was launched in 2003 to conduct the first extra-galactic (beyond our galaxy) ultraviolet survey of the sky. Studying these far-off galaxies-in-progress is helping astronomers understand how galaxies like our own are formed. GALEX has produced some surprising findings about our Milky Way galaxy, including ongoing star formation in an area long considered dead (the “ghost of Mirach”) and an old red giant star with a comet-like tail measuring 13 light-years long. Perhaps most important, data from GALEX has helped support the theory that the universe will continue to expand indefinitely. Taking Baby Pictures Because the universe is expanding, most galaxies are moving away from each other. Those farthest away from Earth—the youngest ones—are traveling so fast that their light waves stretch out toward the red end of the electromagnetic spectrum, a phenomenon known as redshift. (If we were talking about sound waves, you might compare this to a train whistle moving from higher to lower frequency as it passes you by.) Since our atmosphere glows very brightly in the infrared portion of the spectrum, and because young galaxies are shrouded in dust, it’s challenging to make good observations of these stellar nurseries from the ground. But the infrared-detecting Spitzer Space Telescope, launched in 2003, can see through dust to characterize these very distant galaxies and capture stars’ first baby pictures. Spitzer has also demonstrated that terrestrial planets form around most of the nearby sun-like stars in our galaxy, suggesting that the potential for life might be more common than once thought. Spitzer, 100 times more sensitive than any previous infrared telescope, was the first telescope to directly detect the light from planets outside our solar system (exoplanets). And while Hubble first detected the atmosphere of an exoplanet, Spitzer was the first telescope to identify water vapor on an alien world, albeit one too hot to harbor life. Ultimately, astronomers hope to use instruments like those on Spitzer to find water on rocky, habitable planets like Earth. Exploring the Coldest Bodies in the Cosmos With a 3.5 meter-wide mirror, the European Space Agency’s Herschel Observatory is the largest space telescope ever deployed in space. Since 2009, Herschel, orbiting nearly a million miles from Earth, has studied the formation and evolution of galaxies and stars in the early, hidden universe, a place with temperatures below -400˚ Fahrenheit. The colder something is, the longer the wavelengths of light it emits. Herschel is designed to detect far infrared and sub-millimeter light, which is much longer in wavelength than the visible light detected by Hubble. In addition to the early universe, Herschel is observing the chemical makeup of the atmospheres and surfaces of comets, planets, and satellites, as well as the molecular chemistry of the universe. Recently, Herschel discovered an exploding star that released 160,000 to 230,000 Earth-sized masses of dust, suggesting that such supernovae supplied our early universe with dust. [Editor’s note: Download an app of the Online Showcase of Herschel Images for iPhone, iTouch, and iPad, free from the iTunes app store.] ES A Herschel Space Telescope depiction of Interstellar Cloud IC5246 containing the Cocoon Nebula. Interstellar clouds are about 10 degrees above absolute zero (-263 Celsius). Searching for Earth-Like Worlds In its first four months, the Kepler Space Telescope’s photometer located 1,235 possible planets in our galaxy. Around 500 Jupiter-sized exoplanets were previously discovered by 22 imagine Sept/Oct 2011

Table of Contents for the Digital Edition of Imagine Magazine - Johns Hopkins - September/October 2011

Imagine Magazine - Johns Hopkins - September/October 2011
Contents
Big Picture
In My Own Words
Physics Is…
Making the Team
Nuclear by Nature
Physics: The Next Generation
Telescopic Views
Exploring the Mysterious Lives of Stars
Around the Universe in Three Weeks
Selected Opportunities & Resources
Book Buddies
Meeting the (Economics) Challenge
Off the Shelf
Word Wise
Exploring Career Options
One Step Ahead
Planning Ahead for College
Students Review
Creative Minds Imagine
Mark Your Calendar
Knossos Games

Imagine Magazine - Johns Hopkins - September/October 2011