Fireworks from space
Posted: Tuesday, July 03, 2007 7:10 PM by Alan Boyle
NASA / ESA / STScI |
The galaxy NGC 4449 is ablaze with blue and red stars in this Hubble view.
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To mark the Fourth of July, the astronomers behind the Hubble Space Telescope present a fireworks show of cosmic proportions, featuring the starburst galaxy known as NGC 4449. The galaxy's blaze of stellar formation has been going on for billions of years, but it appears to be in the midst of an upswing - perhaps brought on by gravitational interaction with neighboring galaxies 12.5 million light-years away.
Whatever the reason, Hubble was well-positioned to take in the starburst - just one of the cosmic sights worth oohing and ahhing over during the holiday.
In the image released today, bluish-white clusters of hot, massive stars are scattered throughout the galaxy, interspersed with reddish regions of dusty star formation. The starlight throws dark clouds of dust and gas into silhouette, as explained in today's image advisories from the Space Telescope Science Institute as well as the European Space Agency's Hubble Information Center.
Hubble's science team says the galaxy-wide starburst resembles what might be seen much farther away in primordial star-forming galaxies, which grew by sweeping up smaller stellar systems.
"Since NGC 4449 is close enough to be observed in great detail, it is the ideal laboratory for the investigation of what may have occurred during galactic formation and evolution in the early universe," the team says.
There are plenty of galaxies in NGC 4449's neighborhood, in the constellation Canes Venatici, leading astronomers to think that the gravitational interaction between those galaxies is creating the pressures leading to the starburst. They also think NGC 4449 can keep this up for only another billion years or so.
The image was captured by an international team led by Alessandra Aloisi of ESA and the Space Telescope Science Institute, using Hubble's Advanced Camera for Surveys in November 2005. ESA offers a couple of videos that zoom in and pan across the image
Over the years, Hubble and other space telescopes have sent back quite a variety of "fireworks" photos. Here's a selection of the greatest hits, suitable for viewing as you play Handel's Royal Fireworks Music in the background:
- Chandra X-Ray Observatory, 2006: NASA's premier X-ray telescope presents a quadruple scoop of supernova explosions. (By the way, Chandra's team has printed up handouts on "Celestial Fireworks" that educators can order for their classrooms.)
- Gemini Observatory, 2005: How can you resist a picture of the Fireworks Galaxy, taken by the Gemini North Telescope in Hawaii?
- Deep Impact, 2005: The Deep Impact probe blasts a comet for the Fourth, while telescopes on Earth and in space watch the show.
- Spitzer Space Telescope, 2004: NASA's infrared eye spots a pinwheel galaxy in Pegasus that many consider our galaxy's twin.
- Hubble, 2003: Puffs of smoke and sparks are thrown out from N 49, the remnant of a supernova blast in the Large Magellanic Cloud.
- Hubble, 2002: Red, white and blue streamers emanate from Cassiopeia A, a supernova remnant in our own Milky Way galaxy.
- Hubble, 1999: The Fourth may be prime time for an M-80, one of the biggest firecrackers around - but Hubble serves up a completely different kind of M80, which is one of the densest globular star clusters in the Milky Way.
If you're looking for still more dazzlers, check out our Space Gallery for the greatest hits from Hubble and other space probes. I'll be offline on the Fourth to enjoy the local fireworks and other festivities, but regular postings will resume on the Fifth.
