Rocky Exoplanet Discovered With Microlensing Technique

Astronomers from the European Southern Observatory (ESO) announced today the discovery of an exoplanet only 5.5 times the mass of the Earth orbiting a red dwarf star located near the center of the Milky Way galaxy, some 20,000 light years away from our own solar system. The discovery could indicate that rocky planets like the Earth are common throughout the universe.

The discovery of the exoplanet is only the third using a technique called gravitational microlensing. Microlensing is a faint but detectable brightening of light from a more distant object caused by gravitational lensing by a nearer object passing directly in front of it as seen from the Earth. Microlensing does not provide a direct visual observation of intervening bodies but instead indicates their presence indirectly.

A network of robotic telescopes monitors the galaxy 24 hours a day, 7 days a week, looking for microlensing events. Using the Danish 1.54m telescope at ESO La Silla, Chile, astronomers detected a microlensing event on July 11, 2005 by an intervening star less massive than our own Sun. Immediately after the event was detected, notification went out across the network to provide constant coverage of the phenomena. Ten days later, an anomaly in the wanning microlensing effect indicated the presence of a planet.

The planet has been labeled OGLE-2005-BLG-390Lb after the designation for the microlensing event. Astronomers speculate that the planet is cold and probably contains a significant amount of ice in its composition due to its location approximately three times as far from its parent star as the Earth is from the Sun. Its size is sufficient to hold a substantial atmosphere but such an environment may not be hospitable to life as we know it.

According to NASA’s “Planet Quest” site, 159 exoplanets have been detected to date, although other sources give a number closer to 170. Only one other rocky exoplanet candidate has been discovered and only one exoplanet has been directly imaged. Space agencies and astronomers are developing improved telescopes, spacecraft, and techniques to accelerate the detection and direct imaging of Earth-sized exoplanets over the next decade. The improved technologies may also allow scientists to look for evidence of biological markers in the atmospheres of exoplanets to determine the extent of life in our galaxy.

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USGS Ramps Up Earthquake Monitoring Effort

The United States Geological Survey (USGS) National Earthquake Center has unveiled upgraded technology, 24/7 staffing, and a new website to be rolled out over the next few months in response to the 2004 Indian Ocean tsunami and a wider call for better earthquake monitoring. The effort includes HYDRA, a system that will provide more detailed information about earthquakes and their potential for damage based on the region affected. HYDRA is expected to be completed in March 2006.

By providing staffing for operations around the clock, the USGS hopes to provide more timely information about earthquakes soon after they occur. The existing website, located at http://earthquake.usgs.gov, already provides maps, news and an RSS feed about recently detected earthquakes from around the world. A redesign set to debut at the end of January 2006 will enhance the site with information from the new monitoring system.

Emergency appropriations and congressional funding for the effort came last year after the magnitude 9.0 Sumatra Earthquake and tsunami that followed killed nearly 300,000 people on December 26, 2004 in one of the worst natural disasters in recent history. Experts believe that monitoring equipment in the Indian Ocean and improved notification technology could have helped prevent many of these deaths. Although the USGS detected the earthquake immediately after it occurred, they were unable to track down the appropriate authorities in countries in the affected region. Earthquake monitoring equipment and notification already exist for the Atlantic and Pacific oceans.

Earthquakes occur at boundaries where the plates that make up the Earth’s lithosphere and crust collide with, separate from or scrape past each other, as well as localized areas of instability caused by volcanic activity, faulting, and other phenomena. In the United States, 39 states are considered to be at some significant risk of earthquakes. The increasing number of people who live in earthquake prone regions will require continued improvements in current monitoring and notification technologies.

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Raw Images of Active Beauty

Planetary scientists long assumed that the moons of the outer planets were cold, dead, and airless worlds, heavily cratered but otherwise little changed from their original formation. In 1979, Voyager 1, looking back just after its flyby of Jupiter, discovered volcanic activity on Jupiter’s moon Io. Over a year later, Voyager 1 discovered that the atmosphere of Saturn’s moon Titan, first detected in 1944 by Gerard Kuiper, was thicker than the Earth’s, orange, and opaque. When Voyager 2 passed by Neptune’s moon Triton in 1989, it snapped images of geysers erupting despite the extreme cold.

After Galileo toured the Jovian system during the 1990s and early 2000s, planetary scientists views had been irreversibly changed. Gone was a bias for current geological activity only on Earth, replaced with a stunned awareness of just how dynamic our solar system remains after its formation 4.5 billion years ago. By the time Cassini-Huygens entered the Saturnian System in June 2004, expectations were high for new discoveries of current activity to rival those made by the Galileo spacecraft. A year and a half later, these expectations have been exceeded.

With the advanced remote sensing capabilities offered by Cassini, and the successful landing of the Huygens probe, Titan was revealed to be a world more Earth-like than any other yet discovered. Nearly all geological activities present on the Earth appear to have counterparts on Titan. On Titan are low-lying boundaries that look like shorelines, river channels cut out by the recent activity of liquid methane, snow made of clumps of hydrocarbons, and sand dunes that stretch for hundreds of kilometers. Other features look like volcanoes, lakes, and craters (so few that just like the Earth the surface of Titan must be very young.)

The overwhelming realization that Titan was very much like a planet in its own right could not prepare scientists for what came next.

There was another bias at work, one that seemed more like common sense. All the current geological activity discovered in the solar system to date had been on the largest moons, moons nearly as large or much larger than our own. Of these moons – the giants Ganymede, Callisto, Titan, or Luna-comparable Io, Europa, and Triton – only the Earth and Callisto appear to have ancient surfaces unchanged by current geological activity. Smaller moons, and there are many of them, simply do not have the internal energy or structure to support activity. More recent missions had confirmed what was simply common sense. They were the cold, dead, and airless bodies originally assumed by planetary scientists. Even if they were just large enough to be round, the history of activity could be traced to their early formation and rare impacts on their surfaces.

The Saturn moon Enceladus was observed by Cassini as part of its tour of the system. The tiny moon is only 512 kilometers (318 miles) in diameter, with just over the mass expected by theory to lead to roundness instead of irregularity. The first images revealed that the surface was not heavily cratered or ancient as expected by scientists. Instead, the surface appeared to be very young, especially near the south pole.

Other instruments observed Enceladus during these early flybys. Strange surface features labeled the “Tiger Stripes” were warmer than the surrounding terrain. The ice here was incredibly young, perhaps as young as yesterday. Just as surprising was the localized presence of a thin water vapor atmosphere, around a body that was simply too small to hold one.

All of these discoveries were leading somewhere. In images captured by Cassini in November 2005, revealed in a press release on December 6, 2005, were the smoking guns: the plumes of Enceladus. Stretching higher into space than the moon is wide, the plumes erupt with fine particles of water ice from the Tiger Stripes region of Enceladus. Some of these fall onto the surface of the moon, keeping it young, but the rest contribute something surprising to the Saturnian system: Saturn’s own E-ring.

Enceladus has become the first tiny moon to join the Earth, Io, and Triton as worlds known to have current and active volcanic activity. The exact process that drives this activity on Enceladus is still unclear. Scientists believe the tug of war between Titan and Saturn with Enceladus in the middle induce internal friction below the moon’s surface. They are unsure if this results in a partially melted mantle near Enceladus’ south pole, and whether or not this material erupts as liquid water that quickly freezes, or as already frozen water ice particles. What they can be certain of is that their preconceived notions about small moons were wrong.

Expecting one active moon, Cassini mission scientists discovered a second. New raw images returned by Cassini just last week reveal this activity with breathtaking beauty. The high haze layers of Titan seen through Saturn’s rings is a study in detail. And then there is tiny Enceladus, dwarfed by its parent planet and some of its sibling moons, but magnificent with is brilliant and angry plumes in the sunlight. There is certainly scientific data in these images to be categorized and analyzed by scientists when the raw images are cleaned up, but there is also artistic value to be enjoyed.

Walt Whitman wrote about a scientific lecture in a poem entitled “When I Heard the Learn’d Astronomer.” During the lecture, full of facts and data, Whitman writes:

“How soon, unaccountable, I became tired and sick;
Till rising and gliding out, I wander’d off by myself,
In the mystical moist night-air, and from time to time,
Look’d up in perfect silence at the stars.”

There is a great deal that can, has, and will be said about these and other images from Cassini. First, however, these images may invoke in some Walt Whitman’s perfect silence, not through annoyance or boredom, but instead through great awe and wonder. This is a silence that means one cannot, for the moment, speak. One instead simply appreciates.

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New Horizons Launched to Pluto and Beyond

New Horizons was successfully launched today from Kennedy Space Center in Florida, USA after previous delays due to high winds and power outages. A slight delay today because of high clouds preceded a picture perfect launch.

At the moment New Horizons is rocketing away from the Earth and will pass the orbit of the moon in just 9 hours, the fastest yet for a space craft. The speed is necessary to get the spacecraft to Pluto in a reasonable amount of time, just under 10 years. In three months, New Horizons will pass the orbit of Mars, and then in a year it will fly by Jupiter and pick up the extra speed it needs to explore the Kuiper Belt region of our solar system. New Horizons will fly by Pluto and its moons in an event that will last just 24 hours in July 2015, snapping images and gathering other data that could revolutionize our understanding of the solar system and planet formation. After Pluto, New Horizons will be targeted toward other Kuiper Belt objects for exploration.

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New Horizons Rolls Out

Update: Launch postponed to Wednesday, January 18, 2006 due to high winds.

New Horizons and the Atlas rocket on which it sits were rolled out to their launch pad at Kennedy Space Center in Florida, USA yesterday. Only hours remain before the launch window opens up and NASA attempts to launch the piano-sized spacecraft on its mission to explore Pluto and the Kuiper Belt. NASA TV will provide live coverage and a live cam of the launch pad is available on the New Horizons launch site.

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MOC Picture of the Day – Becquerel’s Layers

(Disclosure: Richard Leis is an operations team member located at the University of Arizona for NASA’s Mars Reconnaissance Orbiter (MRO) High Resolution Imaging Science Experiment (HiRISE.))

Although the Mars Reconnaissance Orbiter (MRO) and its High Resolution Imaging Science Experiment (HiRISE) are less than two months away, spacecraft already in orbit around Mars continue to send back breathtaking images of the surface. Case in point is the image to the left taken by Mars Global Surveyor’s (MGS) Mars Orbiter Camera (MOC) of outcrops in Becquerel Crater. These outcrops are believed to be sedimentary layers and perhaps evidence for a lake in the crater in the distant past. Sediments carried into the lake by water channels settled out over time to create distinct layers. The number of discrete layers present in this image suggest that surface water played a role in shaping the martian surface for a significant period of time. While today Mars is a frigid desert, it may have been a much more hospitable and wet planet in its early history.

HiRISE will up the ante in scientific discovery on Mars by providing unprecedented resolution from orbit. The HiRISE science team will continue, among other priorities, to observe surface layering as evidence for water processes on ancient Mars. The orbital efforts of NASA’s MRO, MGS, and Mars Odyssey, ESA’s Mars Express, and periodic rover missions on the ground, represent the most exhaustive exploration of another planetary body.

MOC pictures of the day can be found on the Malin Space Science Systems (MSSS) website. MSSS also provided the Mars Color Imager (MARCI) and Context Imager (CTX) on board MRO. If all of these acronyms are giving you a headache, you are not alone: science team members experience the same symptoms. The list on the right under “More Information” provides full names for select spacecraft and instruments, their acronyms, and links to team websites.

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New Horizons Set for Launch

The first spacecraft mission to the last of the original nine planets in our solar system is schedule for launch on Tuesday, January 17, 2006. New Horizons will begin its journey as the fastest spacecraft ever launched from the Earth. The speed is necessary to reach Pluto and its three known moons in just a little over nine years.

Pluto lies in a region of our solar system known as the Kuiper Belt, a disk-shaped band around the Sun thought to consist of tens of thousands or more small icy bodies. The existence of the Kuiper Belt has been confirmed by the discovery since 1992 of several objects nearly the size of Pluto. Last year, astronomers announced the discovery of a a Kuiper Belt object code named “Xena” that is larger than Pluto. Soon after came announcements about two new moons found orbiting Pluto and a moon found orbiting the tenth planet.

New Horizons will fly by Pluto, its largest moon Charon, and its two smaller moons in July 2015. All instruments on board the spacecraft will have to work quickly to explore the Plutonian system because close approach will last only 24 hours. Once it has passed Pluto, New Horizons will target other Kuiper Belt objects between 2016 and 2020.

Since the discovery of Xena, scientists have been debating just what a planet is, a debate that will have to be resolved before the body can be officially named. If scientists agree that Pluto is just another member of the Kuiper Belt, it may lose its status as a planet and the solar system will officially have eight planets. If instead the diameter of Pluto becomes the new lower limit for defining a planet, then Xena will likely also gain official status as a planet. So far there have been no indications as to when a decision will be reached.

New Horizons will launch from Kennedy Space Center. The window of opportunity for launch begins on Tuesday and lasts through February 14, 2006.

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