By: SPACE.com Staff
Published: 09/14/2012 07:39 AM EDT on SPACE.com
Countless stars at the core of a nearby star cluster look like glowing, multicolored orbs in a stunning new photo snapped by the Hubble Space Telescope.
The image shows the heart of a globular cluster called M4, which is found about 7,200 light-years from Earth -- close enough to make it a prime target for astronomers to study.
M4 contains tens of thousands of stars, researchers said. The cluster hosts many white dwarfs, the leftover cores of old and dying stars whose outer layers have been shed into space.
Hubble has a history with M4. In July 2003, the telescope's observations helped scientists discover an alien planet called PSR B1620-26 b in the cluster. The planet, which is about 2.5 times as massive as Jupiter, is thought to be about 13 billion years old. For comparison, our own solar system is just 4.5 billion years old.
PSR B1620-26 b is also unusual in that it orbits a binary system consisting of a white dwarf and a pulsar, researchers said. A pulsar is a type of neutron star, which is the incredibly dense remnant of a dead "normal" star that has been squeezed down into a city-size object.
Pulsars emit beams of light pointing from their poles that appear to pulse on and off as they sweep toward and away from Earth — hence the name.
M4 is visible to skywatchers with binoculars or a small telescope, NASA officials said. Scan the skies near the red-orange star Antares, in the constellation Scorpius, and you should find it. But don't expect Hubble-level clarity and detail; M4 will appear as a fuzzy ball of light in your eyepiece.
The Hubble Space Telescope is a joint operation of NASA and the European Space Agency and launched in April 1990. It has made more than 1 million science observations since, and it's still going strong.
- Celestial Photos: Hubble Space Telescope's Latest Cosmic Views
- Most Amazing Hubble Discoveries
- Planets Large and Small Populate Our Galaxy (Infographic)
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Messenger Reaches Mercury
While it's not a "discovery," <em>per se</em>, it's a milestone that will no doubt lead to many new findings about the smallest and innermost planet in our solar system. In March, after a 6 1/2-year, 4.9 billion mile journey, <a href="http://www.huffingtonpost.com/2011/03/18/nasa-messenger-mercury_n_837503.html" target="_hplink">NASA's Messenger spacecraft reached Mercury's orbit</a>. Messenger, the first spacecraft to orbit Mercury, <a href="http://messenger.jhuapl.edu/mer_orbit.html" target="_hplink">orbits the planet</a> every 12 hours. In November, <a href="http://www.nasa.gov/mission_pages/messenger/media/MissionExtends.html" target="_hplink">NASA announced that the spacecraft's mission</a>, which was supposed to end on March 17, 2012, would be extended for an additional year.
Pluto's Tiny Moon
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Black Hole Eats A Star
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Huge Mountain Discovered On Asteroid
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'Star Wars'-Like Planet
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'Habitable Zone' Planet Found
Scientists in early December <a href="http://www.huffingtonpost.com/2011/12/05/kepler-22b-new-planet-discovered-habitable-zone_n_1129591.html" target="_hplink">announced the discovery of Kepler-22b</a>, a planet with a temperature of around 72 degrees that's in the so-called <a href="http://en.wikipedia.org/wiki/Habitable_zone" target="_hplink">"Goldilocks," or habitable zone</a>. While the temperature of the 600-light-year away planet could sustain water, it has a radius of 2.4 times that of Earth's, so <a href="http://www.huffingtonpost.com/huff-wires/20111206/us-sci-alien-planet/" target="_hplink">it's probably too big</a> to harbor life.
Biggest Black Holes Ever Discovered
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'Bubbles' At The Edge Of Solar System
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Gypsum On Mars
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Charles Camarda: NASA Innovation