The Night Sky Guy

Hubble Unveils Pluto

NASA has released the most detailed and dramatic images ever taken of the distant dwarf planet Pluto. The images from NASA’s Hubble Space Telescope show an icy, mottled, dark molasses-colored world undergoing seasonal surface color and brightness changes. Pluto has become significantly redder, while its illuminated northern hemisphere is getting brighter.

These changes are most likely consequences of surface ice melting on the sunlit pole and then refreezing on the other pole, as the dwarf planet heads into the next phase of its 248-year-long seasonal cycle. Analysis shows the dramatic change in color took place from 2000 to 2002. The Hubble pictures confirm Pluto is a dynamic world that undergoes dramatic atmospheric changes, not simply a ball of ice and rock. These dynamic seasonal changes are as much propelled by the planet’s 248-year elliptical orbit as by its axial tilt. Pluto is unlike Earth, where the planet’s tilt alone drives seasons. Pluto’s seasons area symmetric because of its elliptical orbit. Spring transitions to polar summer quickly in the northern hemisphere, because Pluto ismoving faster along its orbit when it is closer to the Sun. Ground-based observations, taken in 1988 and 2002 show the mass of the atmosphere doubled during that time. This may be because of warming and melting nitrogen ice.

Hubble Maps Pluto's Changing Surface (courtesy of NASA)

The new Hubble images are giving astronomers essential clues about the seasons on Pluto and the fate of its atmosphere. When the Hubble pictures taken in 1994 are compared to those of 2002 and 2003, astronomers see evidence that the northern polar region has gotten brighter, while the southern hemisphere darkened. These changes hint at very complex processes affecting the visible surface. The images will help planetary astronomers interpret more than three decades of Pluto observations from other telescopes.

“The Hubble observations are the key to tying together these otherdiverse constraints on Pluto and showing how it all makes sense by providing a context based on weather and seasonal changes, which opens other new lines of investigation,” says principal investigator MarcBuie of the Southwest Research Institute in Boulder, Colo.

New horizons at Pluto

These Hubble images, taken by the Advanced Camera for Surveys, will remain the sharpest view of Pluto until NASA’s New Horizons probe is within six months of its flyby during 2015. The Hubble images are invaluable for picking the planet’s most interesting hemisphere for imaging by the New Horizons probe. New Horizons will pass by Pluto so quickly that only one hemisphere will be photographed in detail. Particularly noticeable in the Hubble images is a bright spot that has been independently noted to be unusually rich in carbon monoxide frost. It is a prime target for NewHorizons. “Everybody is puzzled by this feature,” Buie said. New Horizons will get an excellent look at the boundary between this bright feature and a nearby region covered in pitch-black surface material. “The Hubble images also will help New Horizons scientists better calculate the exposure time for each Pluto snapshot which is important for taking the most detailed pictures possible,” Buie said. With no chance for re-exposures, accurate models for the surface of Pluto are essential for properly exposed images. The Hubble images surface variations a few hundred miles across that are too coarse for understanding surface geology. But in terms of surface color and brightness, Hubble reveals a complex-looking world with white, dark-orange, and charcoal-black terrain. The overall color is believed to be a result of ultraviolet radiation from the distant Sun breaking up methane present on Pluto’s surface, leaving behind a dark and red carbon-rich residue.

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New Mars Flyover Video

Check out this amazing computer animation that simulates a flyover of the old Mars Pathfinder landing site. Tip of the hat to StarStryder for this find.

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Biggest and Brightest Moon and Mars Tonight

If you can brave the cold weather then step outside after sunset tonight and take a gander at the full Moon – its the largest and brightest for 2010. Also just beside it is the planet Mars – which just happens to be at Opposition tonight as well – opposite to the sun in the sky- and at its personal best intil 2014.  The spectacular pair will be traveling across the southern sky all night long – so you have plenty of time.

Apparent Mars disk size through a small telescope

If you have a telescope that is at least 5 inches then you can see some nice details on Mars. The easiest will no doubt be the south polar cap and then some of the barren wind-swept darker regions. But even without any optical aid you can clearly see its distinctive ruddy colour which is caused by sunlight reflecting off the iron-oxide rich sand deserts that cover this barren world. Amazing to think that while the moon is less than 400,000 km away, that bright orange star beside it tonight is a planet more than 98 million km away!

A great double feature  for sure. For more info check out my article in National Geographic News.

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Mars at its Best for 2010

Perhaps you’ve noticed a ruddy, star-like beacon rising in the east at night. That’s the planet Mars and it’s been steadily growing bigger and brighter the past few months. Skywatchers are now watching the heavens with anticipation as the Red Planet heads for a close encounter with Earth later this week. First, tonight, the27th it reaches its closest point to Earth, passing within 99 million km and offering backyard astronomers their best views until 2014.

Two days later, on January 29, Mars will reach opposition – risias an added bonus for skywatchers on the night of it’s opposition Mars will pair up with the full Moon, gliding together across the night sky – separated by only 6 degrees – about 12 full moon disks apart.

As the two planets slowly converge along their orbits, earthbound telescopes have begun resolving ever finer details on the disk of Mars. You can see the round disk of the planet through binoculars and a small telescope about 5 to 6 inches will show details like the Martian South polar cap and other surface features.

Mars makes a close pass by Earth every 2 years and while this planetary encounter is not the tightest (2003 opposition was only 56 million km), our neighboring world is easy to spot even with the naked eye. When you see Mars rising above the eastern horizon after sunset this week, just think that its distinctive orange-hue is due to the sunlight relfecting off the iron-rich Martian deserts.

Also wrote a small article on this for National Geographic

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Mars Rover Stuck for Good

NASA just announced that the intrepid Mars rover ‘Spirit’ is about to begin a new, and most likely, final chapter in its adventures. The poor little robotic geologist has been stuck in a sand trap since April of last year and despite numerous attempts to free it – it hasn’t budged much. So today JPL engineers have put up the white flag and are officially giving up trying to free it and have designated the dinner-table sized rover as a stationary science platform.

“Spirit is not dead; it has just entered another phase of its long life,” said Doug McCuistion, director of the Mars Exploration Program at NASA Headquarters in Washington. “We told the world last year that attempts to set the beloved robot free may not be successful. It looks like Spirit’s current location on Mars will be its final resting place.”

Spirit's wheels became embedded when they broke through a crusty surface April 2009 and churned into soft sand hidden underneath

However the race is on to get the rover inched into the right orientation so that it can survive the approaching intense Martian winter. If it’s table-top solar panels can’t get the most solar energy possible, Spirit’s electronics will freeze to death.  “Getting through the winter will all come down to temperature and how cold the rover electronics will get,” said John Callas, project manager at JPL for Spirit and its twin rover, Opportunity. “Every bit of energy produced by Spirit’s solar arrays will go into keeping the rover’s critical electronics warm, either by having the electronics onor by turning on essential heaters.”

But all is not lost in terms of science – far from it say scientists. It’s just going to be a different type of information we are going to learn about the Red Planet -which only a stationary robot could do. “There’s a class of science we can do only with a stationary vehiclethat we had put off during the years of driving,” said Steve Squyres,a researcher at Cornell University and principal investigator for Spirit and Opportunity. “Degraded mobility does not mean the mission ends abruptly. Instead, it lets us transition to stationary science.” One stationary experiment Spirit has begun studies tiny wobbles inthe rotation of Mars to gain insight about the planet’s core. This requires months of radio-tracking the motion of a point on the surface of Mars to calculate long-term motion with an accuracy of a few inches. “If the final scientific feather in Spirit’s cap is determining whether the core of Mars is liquid or solid, that would be wonderful– it’s so different from the other knowledge we’ve gained from Spirit,” said Squyres.

But it has been a great ride for Spirit and its twin Opportunity, which is on the other side of the Red Planet. Both robots landed in January 2004 and have been exploring for six years, far surpassing their original 90-day mission. Opportunity currently is driving toward a large crater called Endeavor and continues to make scientific discoveries. It has driven approximately 12 miles and returned more than 133,000 images.

For more information about Spirit and Opportunity, visit: http://www.nasa.gov/rovers

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NASA Taking Requests for Mars Photos

Mars Reconnaissance Orbiter

The most powerful camera aboard a NASA spacecraft orbiting Mars will soon be taking photo suggestions from the public. Since arriving at Mars in 2006, the High Resolution Imaging Science Experiment, or HiRISE, camera on NASA’s Mars Reconnaissance Orbiter has recorded nearly 13,000 observations of the Red Planet’s terrain. Each image covers dozens of square miles and reveals details as small as a desk. Now, anyone can nominate sites for pictures.

“The HiRISE team is pleased to give the public this opportunity to propose imaging targets and share the excitement of seeing your favorite spot on Mars at people-scale resolution,” said Alfred McEwen, principal investigator for the camera and a researcher at the University of Arizona, Tucson.

Students, researchers and others can view Mars maps using a new online tool to see where images have been taken, check which targets have already been suggested and make new suggestions. “The process is fairly simple,” said Guy McArthur, systems programmer on the HiRISE team at the University of Arizona. “With the tool, you can place your rectangle on Mars where you’d like.”

In addition to identifying the location on a map, anyone nominating a target will be asked to give the observation a title, explain the potential scientific benefit of photographing the site and put the suggestion into one of the camera team’s 18 science themes. The themes include categories such as impact processes, seasonal processes and volcanic processes. The HiRISE science team will evaluate suggestions and put high-priority ones into a queue. Thousands of pending targets from scientists and the public will be imaged when the orbiter’s track and other conditions are right.

To make camera suggestions, visit http://uahirise.org/suggest/

 More information about the MRO mission is at http://www.nasa.gov/mro

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Sunset Sky Show Act 2

Face the southweat sky just after sunset and enjoy the Moon’s encounter with Jupiter. You will have two hours after sunset to catch the pair before they too will set. By tomorrow the Moon will have moved off towards the south and away from the gas giant.

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Red Planet Coming

Courtesy of Ruinerwold, Drenthe, The Netherlands

The planet Mars is quickly getting closer to Earth the next few weeks until January 27, 2010 when it will be only 99 million km away.

Backyard astronomers have been snapping some amazing photos of our neighbouring world showing surprising amounts of detail.

Check out this awesome animation put together from individual images taken by a Dutch stargazer on Dec.15th using only a 10 inch reflector.  Tip of the hat to spaceweather.com for this cool find.

Nasa orbiter snapped this close-up view of the 4 volcanoes; This image is upside down and reversed from animation

Unbeleivably you can actually see white clouds (smudges on the left limb of Mars) above three volcanoes in a vertical row. The lone white cloud to their right is a cloud covered Olympus Mons, the solar system’s largest volcano -  3 times higher than Mt. Everest!  

Meanwhile the white area at the bottom of the disk is the water-ice and frozen carbon dioxide covered Martian south pole. Visible in the late night sky, orange coloured star-like Mars will get brighter and bigger in the telescope as it gets closer to Earth – making for a great target for backyard instruments. Stay tuned for more observing tips in the coming weeks.

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Saturnian Moons Dance

“Like sugar plum fairies in The Nutcracker, the moons of Saturn performed a celestial ballet before the eyes of NASAs Cassini spacecraft. The new movies frame the moons silent dance against the majestic sweep of the planets rings and show as many as four moons gliding around one another.”

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Two Worlds Meet Tonight

Jupiter and Moon Tonight

The waxing crescent Moon will be parked next to Jupiter this evening. The king of the planets will be about 6 degrees – or 12 full moon disks away from Luna.

An interesting challenge for naked-eye skywatchers is to try and spot the pair during daylight. How long before the sun sets can you see starlike Jupiter – The Moon will make for a convenient guide to find the gas giant. Also remember a steadily held pair of binoculars will show you the moons of Jupiter! Monday night the Moon will have move even closer to Jupiter – so don’t miss this double sky show!

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