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Astronomy Picture of the Day 02-04-04
NASA ^ | 02-04-04 | Robert Nemiroff and Jerry Bonnell

Posted on 02/03/2004 9:55:55 PM PST by petuniasevan

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2004 February 3
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

Opportunity's Horizon
Credit: Mars Exploration Rover Mission, JPL, NASA

Explanation: Remarkably, the Opportunity Mars rover lies in a small martian impact crater about 3 meters deep and 22 meters wide. For 360 degrees, Opportunity's horizon stretches to the right in this new color mosaic image from the rover's panoramic camera. Notable in this view of the generally dark, smooth terrain are surface imprints left by the lander's airbags and an outcropping of light-colored, layered rock about 8 meters away toward the northwest. Though they look imposing, the rocks in the tantalizing outcrop are only a few centimeters high and will be dwarfed by the cart-sized rover itself during future close-up investigations. Opportunity has now rolled off its lander and, along with the restored Spirit rover, is directly exploring the martian surface.


TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: mars; opportunity; rover
Supernova blast bonanza in nearby galaxy
SPACE TELESCOPE SCIENCE INSTITUTE NEWS RELEASE
Posted: February 3, 2004

The nearby dwarf galaxy NGC 1569 is a hotbed of vigorous star birth activity which blows huge bubbles that riddle the main body of the galaxy. The galaxy's "star factories" are also manufacturing brilliant blue star clusters. This galaxy had a sudden and relatively recent onset of star birth about 25 million years ago, which subsided about the time the very earliest human ancestors appeared on Earth.


Credit: ESA, NASA and P. Anders (Gottingen University Galaxy Evolution Group, Germany)
Download a larger image here

 
In this new image, taken with NASA's Hubble Space Telescope, the bubble structure is sculpted by the galactic super-winds and outflows caused by a colossal input of energy from collective supernova explosions that are linked with a massive episode of star birth.

One of the still unresolved mysteries in astronomy is how and when galaxies formed and how they evolved. Most of today's galaxies seem to have been already fully formed very early on in the history of the universe (now corresponding to a large distance away from us), their formation involving one or more galaxy collisions and/or episodes of strongly enhanced star formation activity (so-called starbursts).

While any galaxies that are actually forming are too far away for detailed studies of their stellar populations even with Hubble, their local counterparts, nearby starburst and colliding galaxies, are far easier targets.

NGC 1569 is a particularly suitable example, being one of the closest starburst galaxies. It harbors two very prominent young, massive clusters plus a large number of smaller star clusters. The two young massive clusters match the globular star clusters we find in our own Milky Way galaxy, while the smaller ones are comparable with the less massive open clusters around us.

NGC 1569 was recently investigated in great detail by a group of European astronomers who published their results in the January 1, 2004 issue of the British journal, Monthly Notices of the Royal Astronomical Society. The group used several of Hubble's high-resolution instruments, with deep observations spanning a wide wavelength range, to determine the parameters of the clusters more precisely than is currently possible from the ground.

The team found that the majority of clusters in NGC 1569 seem to have been produced in an energetic starburst that started around 25 million years ago and lasted for about 20 million years. First author Peter Anders from the Gottingen University Galaxy Evolution Group, Germany says, "We are looking straight into the very creation processes of the stars and star clusters in this galaxy. The clusters themselves present us with a fossil record of NGC 1569's intense star formation history."

The bubble-like structures seen in this image are made of hydrogen gas that glows when hit by the fierce winds and radiation from hot young stars and is racked by supernovae shocks. The first supernovae blew up when the most massive stars reached the end of their lifetimes roughly 20-25 million years ago. The environment in NGC 1569 is still turbulent and the supernovae may not only deliver the gaseous raw material needed for the formation of further stars and star clusters, but also actually trigger their birth in the tortured swirls of gas.

The color image is composed of 4 different exposures with Hubble's Wide Field and Planetary Camera 2 through the following filters: a wide ultraviolet filter (shown in blue), a green filter (shown in green), a wide red filter (shown in red), and a Hydrogen alpha filter (also shown in red).

The Space Telescope Science Institute (STScI) is operated by the Association of Universities for Research in Astronomy, Inc. (AURA), for NASA, under contract with the Goddard Space Flight Center, Greenbelt, MD. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA).

1 posted on 02/03/2004 9:55:56 PM PST by petuniasevan
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To: MozartLover; Joan912; NovemberCharlie; snowfox; Dawgsquat; Vigilantcitizen; theDentist; ...


2 posted on 02/03/2004 9:57:22 PM PST by petuniasevan (Don't drive me crazy -- it's within walking distance.)
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To: petuniasevan
Thank You.
3 posted on 02/03/2004 10:09:28 PM PST by Soaring Feather (~ I do Poetry and Party among the stars~)
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To: petuniasevan
FYI, interesting Mars Photo discussion here, from this shot. http://www.freerepublic.com/focus/f-news/1071395/posts
4 posted on 02/04/2004 11:30:18 AM PST by CJ Wolf
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To: petuniasevan
Thanks for the ping
5 posted on 02/04/2004 3:21:20 PM PST by firewalk
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To: petuniasevan
Thanks for the ping.
6 posted on 02/04/2004 5:16:18 PM PST by sistergoldenhair
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