Universe Today

March 6, 2013December 23, 2015 by Nancy Atkinson

Rare Eclipsing Binary Stars Provide Refined Measurements in the Universe

The Large Magellanic Cloud, a neighboring galaxy to the Milky Way. The positions of eight faint and rare cool eclipsing binary stars are marked with crosses. Credit: ESO/R. Gendler

Precise observations of a rare class of binary stars have now allowed a team of astronomers to improve the measurement of the distance to one of our neighboring galaxies, the Large Magellanic Cloud, and in the process, refine the Hubble Constant, an astronomical calculation that helps measure the expansion of the Universe. The astronomers say this is a crucial step towards understanding the nature of the mysterious dark energy that is causing the expansion to accelerate.

The team used telescopes at ESO’s La Silla Observatory in Chile, the Las Campanas Observatory also in Chile and two from the University of Hawaii at Manoa, and the Las Campanas Observatoryas well as others around the globe. These results appear in the 7 March 2013 issue of the journal Nature.

The new distance to the LMC is 163,000 light-years. The LMC is not the closest galaxy to the Milky Way; Canis Major Dwarf Galaxy, discovered in 2003 is considered the actual nearest neighbor at 42,000 light-years from the Galactic Center, and the Sagittarius Dwarf Elliptical Galaxy is about 50,000 light-years from the core of the Milky Way.

Astronomers ascertain the scale of the universe by first measuring the distances to close-by objects and then using them as standard candles — objects of known brightness — to pin down distances farther and farther out in the universe.

Up to now, finding an accurate distance to the LMC has proved elusive. Stars in that galaxy are used to fix the distance scale for more remote galaxies, so it is crucially important.

“This is a true milestone in modern astronomy. Because we know the distance to our nearest neighbor galaxy so precisely, we can now determine the rate at which the universe is expanding — the Hubble constant — with much better accuracy. This will allow us to investigate the physical nature of the enigmatic dark energy, the cause of the accelerated expansion of the universe,” says Dr. Rolf-Peter Kudritzki, an astronomer at the University of Hawaii’s Institute for Astronomy.

“For extragalactic astronomers,” said Dr. Fabio Bresolin, also from UH, “the distance to the Large Magellanic Cloud represents a fundamental yardstick with which the whole universe can be measured. Obtaining an accurate value for it has been a major challenge for generations of scientists. Our team has overcome the difficulties using an exquisitely accurate method, and is already working to cut the small remaining uncertainty by half in the next few years.”

The team worked out the distance to the LMC by observing rare close pairs of stars known as eclipsing binaries. As these stars orbit each other, they pass in front of each other. When this happens, as seen from Earth, the total brightness drops, both when one star passes in front of the other and, by a different amount, when it passes behind.

Read another recent article about studies that used eclipsing binaries to study the Light-travel-time Effect

By tracking these changes in brightness very carefully, and also measuring the stars’ orbital speeds, it is possible to work out how big the stars are, what their masses are, and other information about their orbits. When this is combined with careful measurements of the total brightness and colors of the stars, remarkably accurate distances can be found.

“Now we have solved this problem by demonstrably having a result accurate to 2%,” states Wolfgang Gieren (Universidad de Concepción, Chile) and one of the leaders of the team.

Sources: University of Hawaii, ESO

March 6, 2013December 23, 2015 by Nancy Atkinson

‘First Light’ Image for Telescope on the International Space Station

The first light from the new ISERV camera system, taken on February 16, 2013 shows the Rio San Pablo as it empties into the Golfo de Montijo in Veraguas, Panama. NASA image by Burgess Howell, SERVIR Global program.

As we reported in January, a new telescope was installed on the International Space Station – not to observe the stars, but instead look back to Earth to acquire imagery of specific areas of the world for disaster analysis and environmental studies. Called ISERV (International Space Station SERVIR Environmental Research and Visualization System), it has now taken its first image. Above is the “first light” from the new ISERV, taken at 1:44 p.m. local time on February 16, 2013.

No, this is not a giant tree trunk! It is the Rio San Pablo as it empties into the Golfo de Montijo in Veraguas, Panama.

The telescope is a modified off-the-shelf Celestron telescope, the Celestron CPC 925, a 9.25? diffraction limited Schmidt-Cassegrain telescope and if you were to buy a un-modified version, it would cost $2,500 including the mount.

The ISERV version was modified at the Marshall Space Flight Center, which is where it is controlled from, as well. It is installed in the Window Observational Research Facility (WORF) in the station’s Destiny laboratory. With a resolution down to 3.2 meters (10 feet), it will be possible to spot fairly small details and objects.

Canadian astronaut Chris Hadfield with the new ISERV (International Space Station SERVIR Environmental Research and Visualization System), a modified Celestron telescope for Earth observation. Credit: NASA/CSA

This ISERV Pathfinder is intended as an engineering exercise, with the long-term goal of developing a system for providing imagery to developing nations as they monitor natural disasters and environmental concerns.

“ISERV’s full potential is yet to be seen, but we hope it will really make a difference in people’s lives,” said principal investigator Burgess Howell of NASA’s Marshall Space Flight Center. “For example, if an earthen dam gives way in Bhutan, we want to be able to show officials where the bridge is out or where a road is washed out or a power substation is inundated. This kind of information is critical to focus and speed rescue efforts.”

The system will use on positioning software to know where the space station is at each moment and to calculate the next chance to view a particular area on the ground. If there’s a good viewing opportunity, the SERVIR team will instruct the camera to take high-resolution photographs at 3 to 7 frames per second, totaling as many as 100 images per pass.

The current mission will test the limitations of this ISERV system and identify measures for improvements in a more permanent system. For instance, the engineering team is working to determine how the geometry of the ISS window affects the imagery; how much sunlight is needed to capture clear images; and how the atmosphere affects that clarity. This characterization phase will last several weeks to a few months. Eventually, ISERV should be made available to the natural hazards community and to basic research scientists.

Source: NASA Earth Observatory

March 6, 2013December 23, 2015 by Nancy Atkinson

Next Soyuz Crew Will Take 6-Hour Fast-Track to Space Station

Russian Soyuz spacecraft, docked to the International Space Station. Credit: NASA.

The next Soyuz crew will be the first to try out the new abbreviated four-orbit rendezvous with the International Space Station. This relatively new, modified launch and docking profile for the Russian ships has been tried successfully with three Progress resupply vehicles, and now Roscosmos and NASA have agreed to try it on a human flight.

“We tried this approach on the cargo vehicles, and now we will try to do it on the manned vehicles,” said Sergei Krikalev, former cosmonaut, who now leads the Gagarin Cosmonaut Training Center near Moscow, speaking through an interpreter on NASA TV. “Now we have onboard new machinery and new software, so the vehicle is more autonomous, so it’s possible to do a lot onboard the vehicle and to calculate the burns so they don’t consume a lot of fuel.”

In the past, Soyuz manned capsules and Progress supply ships were launched on trajectories that required about two days, or 34 orbits, to reach the ISS. The new fast-track trajectory has the rocket launching shortly after the ISS passes overhead. Then, additional firings of the vehicle’s thrusters early in its mission expedites the time required for a Russian vehicle to reach the Station.

Liftoff of the Soyuz TMA-08M spacecraft is scheduled for 4:43 p.m. EDT (20:43 UTC) on March 28 from the Baikonur Cosmodrome in Kazakhstan. Docking is set for 10:31 p.m. EDT (02:31 UTC).

“The Soyuz is not the most comfortable vehicle to be in for an extended period of time,” said NASA astronaut Chris Cassidy who is part of the Expedition 35/36 crew who will make the first fast-track flight. “The toilet is right next to where you sleep which are right next to your buddy and eating and all; it’s like living for a day in a smart car or a Volkswagen Beetle….So the benefit to us is we get to the space station faster with the facilities that it offers, much more comfortable type of environment to be in and it also demonstrates some technology that’s useful in getting to the space station on that same day.”

One of the reasons given in the past for having the two-day or even three-day flight in the Soyuz was to allow the crew members time to get acclimated to being in a weightless environment. This new fast approach doesn’t allow for that, but Cassidy said he doesn’t think that thinking is really applicable, since the cramped Soyuz is so different from the voluminous space station.

“The adaptation of that I think is a little bit different,” he said. “You’re really not truly adapting in that day and a half. Two days on the Soyuz, that same adaptation that you’ll have once you get to the space station just because it’s a different perspective for your brain to get its arms around.”

The Soyuz took the first crew to the International Space Station in November 2000, and since that time, at least one Soyuz has always been at the Station, generally to bring the crews back and forth, but also to serve as a lifeboat should the crew have to return to Earth unexpectedly. Now that the space shuttles have been retired, the Soyuz is currently the only way for ISS crews to go to and from the Station. When there is a full crew of six on board, that means two Soyuz are docked at the ISS.

SpaceX is shooting for sometime in 2015 for the first crew flights of the Dragon to the ISS.

March 6, 2013December 23, 2015 by Tammy Plotner

Black Holes, Fermi Bubbles and the Milky Way

Deep at the heart of our galaxy lurks a black hole. This isn’t exciting news, but neither is it a very exciting place. Or is it? While all might be quiet on the western front now, there may be evidence that our galactic center was once home to some pretty impressive activity – activity which may have included multiple collision events and mergers of black holes as it gorged on a satellite galaxies. Thanks to new insights from a pair of assistant professors, Kelly Holley-Bockelmann at Vanderbilt and Tamara Bogdanovic at Georgia Institute of Technology, we have more evidence which points to the Milky Way’s incredibly active past.

“Tamara and I had just attended an astronomy conference in Aspen, Colorado, where several of these new observations were announced,” said Holley-Bockelmann. “It was January 2010 and a snow storm had closed the airport. We decided to rent a car to drive to Denver. As we drove through the storm, we pieced together the clues from the conference and realized that a single catastrophic event – the collision between two black holes about 10 million years ago – could explain all the new evidence.”

Now, imagine a night sky illuminated by a a huge nebula, one that covers half the celestial sphere. This isn’t a dream, it’s a reality. These massive lobes of high-energy radiation are known as Fermi bubbles and they cover a region some 30,000 light years on either side of the Milky Way’s core. While we can’t observe them directly in visible light, these particles are moving along at close to 186,000 miles per second and glowing in x-ray and gamma ray wavelengths.

According to Fulai Guo and William G. Mathews of the University of California at Santa Cruz: “The Fermi bubbles provide plausible evidence for a recent powerful AGN jet activity in our Galaxy, shedding new insights into the origin of the halo CR population and the channel through which massive black holes in disk galaxies release feedback energy during their growth.”

However, our galactic center is home to more than just some incredible bubbles – it’s the location of three of the most massive clusters of young stars within the Milky Way’s realm. Known as the Central, Arches and Quintuplet clusters, each grouping houses several hundred hot, young stars which dwarf the Sun. They will live short, bright, violent lives… burning out in a scant few million years. Because they live fast and die young, these cluster stars must have formed within recent years during a eruption of star formation near the galactic center – another clue to this cosmic puzzle.

“Because of their high mass, and apparent top-heavy IMF, the Galactic Center clusters contain some of the most massive stars in the Galaxy. This is important, as massive stars are key ingredients and probes of astrophysical phenomena on all size and distance scales, from individual star formation sites, such as Orion, to the early Universe during the age of reionization when the first stars were born. As ingredients, they control the dynamical and chemical evolution of their local environs and individual galaxies through their influence on the energetics and composition of the interstellar medium.” says Donald F. Figer. “They likely play an important role in the early evolution of the first galaxies, and there is evidence that they are the progenitors of the most energetic explosions in the Universe, seen as gamma ray bursts. As probes, they define the upper limits of the star formation process and their presence likely ends further formation of nearby lower mass stars. They are also prominent output products of galactic mergers, starburst galaxies, and active galactic nuclei.”

To deepen the mystery, take a closer look at our central black hole. It spans about 40 light seconds in diameter and weighs about four million solar masses. According to what we know, this should produce intensive gravitational tides – ones that should be sucking in the surroundings. So how is it that astronomers have uncovered groups of new, bright stars closer than 3 light years from the event horizon? Of course, they could be on their way to oblivion, but the data shows these stars seem to have formed there. That’s quite a feat considering it would require a molecular cloud 10,000 times more dense than the one located at our galactic center! Shouldn’t there also be old stars located there as well? The answer is yes, there should be… but there are far fewer than what we can observe and what current theoretical models predict.

Holley-Bockelmann wasn’t about to let the problem rest. When she returned home, she enlisted the aid of Vanderbilt graduate student Meagan Lang to help solve the riddle. Then they recruited Pau Amaro-Seoane from the Max Planck Institute for Gravitational Physics in Germany, Alberto Sesana from the Institut de Ciències de l’Espai in Spain, and Vanderbilt Research Assistant Professor Manodeep Sinha to help. With so many bright minds to help solve this riddle, they soon arrived at a plausible explanation – one which matches observations and allows for testable predictions.

According to their theory, a Milky Way satellite galaxy began migrating towards our core. As it merged with our galaxy, its mass was torn away, leaving only its black hole and a small collection of gravitationally bound stars. After several million years, this “leftover” eventually reached the galactic center and the black holes began to merge. As the smaller black hole was swirled around the larger, it plowed up huge furrows of gas and dust, pushing it into the larger black hole and created the Fermi bubbles. The dueling gravitational forces weren’t gentle… these intense tides were quite capable of compressing the molecular clouds surrounding the core into the density required to produce fresh, young stars. Perhaps the very young stars we now observe at the galactic center?

However, there’s more to the picture than meets the eye. This same plowing of the cosmic turf would have also pushed out existing older stars from the vicinity of the massive central black hole. It’s a scene which fits current models where a black hole merger flings stars out into the galaxy at hyper velocities… a scene which fits the observation of a lack of old stars at the boundaries of our supermassive black hole.

“The gravitational pull of the satellite galaxy’s black hole could have carved nearly 1,000 stars out of the galactic centre,” said Bogdanovic. “Those stars should still be racing through space, about 10,000 light years away from their original orbits.”

Can any of this be proved? The answer is yes. Thanks to large scale surveys like the Sloan Digital Sky Survey, we should be able to pinpoint stars moving at a higher velocity than stars which haven’t been subjected to a similar interaction. If astronomers like Holley-Bockelmann and Bogdanovic look at the hard evidence, they are likely to discover a credible number of high velocity stars which will validate their Milky Way merger model.

Or are they just blowing bubbles?

March 5, 2013April 26, 2016 by Nancy Atkinson

Evidence for a Deep Ocean on Europa Might be Found on its Surface

Astronomers hypothesize that chloride salts bubble up from the icy moon's global liquid ocean and reach the frozen surface where they are bombarded with sulfur from volcanoes on Jupiter's largest moon, Io. This illustration of Europa (foreground), Jupiter (right) and Io (middle) is an artist's concept. Credit: Keck Observatory.

Astronomer Mike Brown and his colleague Kevin Hand might be suffering from “Pump Handle Phobia,” as radio personality Garrison Keillor calls it, where those afflicted just can’t resist putting their tongues on something frozen to see if it will stick. But Brown and Hand are doing it all in the name of science, and they may have found the best evidence yet that Europa has a liquid water ocean beneath its icy surface. Better yet, that vast subsurface ocean may actually shoot up to Europa’s surface, on occasion.

In a recent blog post, Brown pondered what it would taste like if he could lick the icy surface of Jupiter’s moon Europa. “The answer may be that it would taste a lot like that last mouthful of water that you accidentally drank when you were swimming at the beach on your last vacation. Just don’t take too long of a taste. At nearly 300 degrees (F) below zero your tongue will stick fast.”

His ponderings were based on a new paper by Brown and Hand which combined data from the Galileo mission (1989 to 2003) to study Jupiter and its moons, along with new spectroscopy data from the 10-meter Keck II telescope in Hawaii.

The study suggests there is a chemical exchange between the ocean and surface, making the ocean a richer chemical environment.

“We now have evidence that Europa’s ocean is not isolated—that the ocean and the surface talk to each other and exchange chemicals,” said Brown, who is an astronomer and professor of planetary astronomy at Caltech. “That means that energy might be going into the ocean, which is important in terms of the possibilities for life there. It also means that if you’d like to know what’s in the ocean, you can just go to the surface and scrape some off.”

“The surface ice is providing us a window into that potentially habitable ocean below,” said Hand, deputy chief scientist for solar system exploration at JPL.

Europa’s ocean is thought to cover the moon’s whole globe and is about 100 kilometers (60 miles) thick under a thin ice shell. Since the days of NASA’s Voyager and Galileo missions, scientists have debated the composition of Europa’s surface.

Salts were detected in the Galileo data – “Not ‘salt’ as in the sodium chloride of your table salt,” Brown wrote in his blog, “Mike Brown’s Planets,” “but more generically ‘salts’ as in ‘things that dissolve in water and stick around when the water evaporates.’”

That idea was enticing, Brown said, because if the surface is covered by things that dissolve in water, that strongly implies that Europa’s ocean water has flowed on the surface, evaporated, and left behind salts.

But there were other explanations for the Galileo data, as Europa is constantly bombarded by sulfur from the volcanoes on Io, and the spectrograph that was on the Galileo spacecraft wasn’t able to tell the difference between salts and sulfuric acid.

But now, with data from the Keck Observatory, Brown and Hand have identified a spectroscopic feature on Europa’s surface that indicates the presence of a magnesium sulfate salt, a mineral called epsomite, that could have formed by oxidation of a mineral likely originating from the ocean below.

This view of Jupiter's moon Europa features several regional-resolution mosaics overlaid on a lower resolution global view for context. The regional views were obtained during several different flybys of the moon by NASA's Galileo mission. Image credit: NASA/JPL-Caltech/University of Arizona. — This view of Jupiter’s moon Europa features several regional-resolution mosaics overlaid on a lower resolution global view for context. The regional views were obtained during several different flybys of the moon by NASA’s Galileo mission. Image credit: NASA/JPL-Caltech/University of Arizona.

Brown and Hand started by mapping the distribution of pure water ice versus anything else. The spectra showed that even Europa’s leading hemisphere contains significant amounts of non-water ice. Then, at low latitudes on the trailing hemisphere — the area with the greatest concentration of the non-water ice material — they found a tiny, never-before-detected dip in the spectrum.

The two researchers tested everything from sodium chloride to Drano in Hand’s lab at JPL, where he tries to simulate the environments found on various icy worlds. At the end of the day, the signature of magnesium sulfate persisted.

The magnesium sulfate appears to be generated by the irradiation of sulfur ejected from the Jovian moon Io and, the authors deduce, magnesium chloride salt originating from Europa’s ocean. Chlorides such as sodium and potassium chlorides, which are expected to be on the Europa surface, are in general not detectable because they have no clear infrared spectral features. But magnesium sulfate is detectable. The authors believe the composition of Europa’s ocean may closely resemble the salty ocean of Earth.

While no one is going to be traveling to Europa to lick its surface, for now, astronomers will continue to use the modern giant telescopes on Earth to continue to “take spectral fingerprints of increasing detail to finally understand the mysterious details of the salty ocean beneath the ice shell of Europa,” Brown said.

Also, NASA is looking into options to explore Europa further. (Universe Today likes the idea of a big drill or submarine!)

But in the meantime what happens next? “We look for chlorine, I think,” Brown wrote. “The existence of chlorine as one of the main components of the non-water-ice surface of Europa is the strongest prediction that this hypothesis makes. We have some ideas on how we might look; we’re working on them now. Stay tuned.”

Read Brown & Hand’s paper.

Sources: Mike Brown’s Planets, Keck Observatory, JPL

March 5, 2013December 23, 2015 by Nancy Atkinson

Update on the Comet that Might Hit Mars

Simulation of the close approach of C/2013 A1 to Mars in Celestia using info from the Minor Planet Center. Credit: Ian Musgrave/Astroblog.

The latest trajectory of comet 2013 A1 (Siding Spring) generated by the Near-Earth Object Program Office at the Jet Propulsion Laboratory indicates the comet will pass within 186,000 miles (300,000 kilometers) of Mars in October of 2014, and there is a strong possibility that it might pass much closer. The NEO Program Office’s current estimate based on observations through March 1, 2013, has it passing about 31,000 miles (50,000 kilometers) from the Red Planet’s surface. That distance is about two-and-a-half times that of the orbit of outermost moon, Deimos.

Previous estimates put it on a possible collision course with Mars.

This video, above, is based on comet’s orbit calculated by Leonid Elenin, which has it is coming within 58,000 km, and visualized by SpaceEngine software.

The trajectory for comet Siding Spring is being refined as more observations are made. Rob McNaught discovered this comet on Jan. 3, 2013, at Siding Spring Observatory in Australia, and looking back at archival observations has unearthed more images of the comet, extending the observation interval back to Oct. 4, 2012. Further refinement to its orbit is expected as more observational data is obtained.

“At present, Mars lies within the range of possible paths for the comet and the possibility of an impact cannot be excluded,” said an update today from JPL. “However, since the impact probability is currently less than one in 600, future observations are expected to provide data that will completely rule out a Mars impact.”

JPL’s update also outlined how during the close Mars approach, the comet will likely achieve a total visual magnitude of zero or brighter, as seen from Mars-based spacecraft. From Earth, the comet is not expected to reach naked eye brightness, but it may become bright enough (about magnitude 8) that it could be viewed from the southern hemisphere in mid-September 2014, using binoculars, or small telescopes.

Siding Spring likely originated from the Oort cloud. Amateur and professional astronomers will be keeping an eye on this comet’s trajectory to determine if it will end up hitting Mars or not.

Source: JPL

March 5, 2013December 23, 2015 by Bob King

Comet PANSTARRS Crosses Paths With Zodiacal Light

The tapering wedge of the zodiacal light reaches from the western horizon on March 3, 2013 toward the bright Planet Jupiter at top. Credit: Bob King

With the much-anticipated PANSTARRS comet emerging into the evening sky this week, we might keep our eyes open to another sight happening at nearly the same time. If you live where the sky to the west is very dark, look for the zodiacal light, a tapering cone of softly-luminous light slanting up from the western horizon toward the bright planet Jupiter near twilight’s end.

It makes its first appearance about 75 minutes after sunset and lingers for an hour and a half. Sunlight reflected from countless dust particles shed by comets and to a lesser degree by colliding asteroids is responsible for this little-noticed phenomenon. Comets orbiting approximately in the plane of the solar system between Jupiter and the sun are its key contributors. Jupiter’s gravity stirs the works into a pancake-like cloud that permeates the inner solar system.

The zodiacal is formed of dust left behind by comets orbiting between Jupiter and the sun and forms a pancake-like structure in the plane of the planets. Illustration: Bob King

More of us would be more aware of the zodiacal light if we knew better when and where to look. While a dark sky is essential, you don’t have to move to the Atacama Desert. I live 9 miles from a moderate-sized, light-polluted city; the western sky is terrible but the east is plenty dark and ideal for watching the morning zodiacal light in the fall months.

Near its base, the cone easily matches the summer Milky Way in brightness and spans about two fists held horizontally at arm’s length. At first glance you’d be tempted to think it was the lingering glow of twilight until you realize it’s nearly two hours after sunset. The farther you follow up the cone, the fainter and narrower it becomes. From top to bottom the light pyramid measures nearly five fists long. In other words, it’s HUGE.

The pyramid-shaped zodiacal light cone is centered on the same path the sun and planets take across the sky called the ecliptic. This map shows the sky 90 minutes after sunset in early March facing west. Created with Stellarium — The pyramid-shaped zodiacal light cone is centered on the same path the sun and planets take across the sky called the ecliptic. This map shows the sky facing west 90 minutes after sunset in early March. Created with Stellarium

The zodiacal light is centered on the same path the sun and planets take through the sky called the ecliptic, an imaginary circle that runs through the familiar 12 constellations of the zodiac. Every spring, that path intersects the western horizon at dusk at a steep angle, tilting the light cone up into clear view. A similar situation happens in the eastern sky before dawn in October. Of course the light’s there all year long, but we don’t notice it because it’s slanted at a lower angle and blends into the hazy air near the horizon.

The zodiacal light we see at dusk is a portion of the larger zodiacal dust cloud that extends at least to Jupiter’s distance (~500 million miles) on either side of the Sun, making it the single biggest thing in the Solar System visible with the naked eye. Under exceptional skies, like those found on distant mountaintops or far from city lights, the cone tapers into the zodiacal band that completely encircles the sky.

The gegenschein is the small, oval glow within the zodiacal band seen in this photo taken at the European Southern Observatory in Chile. Credit: ESO / Yuri Beletsky

Exactly opposite the sun around local midnight, you might see an enhancement in the band called the gegenschein (GAY-gen-shine). This eerie oval glow is caused by sunlight shining directly on interplanetary dust grains and then back to your eye. A similar boost happens for the same reason at the time of full moon.

Deep connections abound throughout the universe. Over time, much of the comet dust in the zodiacal cloud either spirals inward toward the sun or gets pushed outward by solar radiation. The fact that we can still see it today means it’s continually being replenished by the silent comings and goings of comets.

Comet C/2011 L4 PANSTARRS photographed with a 200mm telephoto lens over Bridgetown, Western Australia on March 3. Credit: Jim Gifford — Comet C/2011 L4 PANSTARRS photographed with a 200mm telephoto lens over Bridgetown, Western Australia on March 3.
Credit: Jim Gifford

Consider Comet L4 PANSTARRS. Dribs and drabs of dust sputtered from this comet during its current trip to the inner solar system may find their way into the zodiacal cloud to secure its presence for future sky watchers. How wonderful then the comet and the ghostly light should happen to be at their best the very same time of year.

Zodical light touching the Seven Sisters star cluster also known as the Pleiades March 19, 2012. Credit: Bob King

Now through March 13 is the ideal time for zodiacal light viewing. If you begin your evening with Comet PANSTARRS, stick around until nightfall to spot the light. Face west and cast a wide view across the sky, sweeping your gaze from left to right and back again. Look for a big, hazy glow reaching from the horizon toward the Planet Jupiter. After the 13th, the waxing moon will wash out the subtle light cone for a time. Another “zodiacal window” opens up in late March through mid-April when the moon comes up too late to spoil the view.

As you take in the sight, consider how something as small as a dust mote, when teamed with its mates, can create a jaw-dropping comet’s tail, meet its end in the fiery finale of a meteor shower or span a billion miles of space.

March 5, 2013December 23, 2015 by David Dickinson

Why This Weekend is Perfect for a Messier Marathon

To 'scopes, get set, marathon! (A homemade 14" Gregorian reflector, photo by author).

This coming weekend presents the first window for 2013 to complete a challenge in the realm of backyard astronomy and visual athletics. With some careful planning, persistence, and just plain luck, you can join the vaunted ranks of those seasoned observers who’ve seen all 110 objects in the Messier catalog… in one night.

Observing all of the objects in Messier’s catalog in a single night has become a bit of a sport over the last few decades for northern hemisphere observers, and several clubs and organizations now offer certificates for the same. The catalog itself was a first attempt by French astronomer Charles Messier to catalog the menagerie of “faint fuzzies” strewn about the northern hemisphere sky.

Not that Charles knew much about the nature of what he was seeing. The modern Messier catalog includes a grab bag collection of galaxies, nebulae, open and globular clusters and more down to magnitude +11.5, all above declination -35°. Charles carried out his observations from Paris France at latitude +49° north. Unfortunately, this also means that Messier catalog is the product of Charles Messier’s northern-based vantage point. The northernmost objects in the catalog are Messiers 81 & 82 at declination +69°, which never get above the horizon for observers south of latitude -21°. His initial publication of the catalog in 1774 contained 45 objects, and his final publication contained 103, with more objects added based on his notes after his death in 1817. (Fun fact: Messier is buried in the famous Père Lachaise Cemetery in Paris, site of other notable graves such as those of Chopin and Jim Morrison).

M51, the Whirlpool Galaxy, one of the more photogenic objects in the Messier catalog. (Credit: NASA/Hubble Heritage Project).

There’s a fair amount of controversy on Messier’s motivations and methods for compiling his catalog. The standard mantra that will probably always be with us is that Messier was frustrated with stumbling across these objects in his hunt for comets and decided to catalog them once and for all. He eventually discovered 13 comets in his lifetime, including Comet Lexell which passed only 2.2 million kilometres from Earth in 1770.

No one is certain where the modern tradition of the Messier Marathon arose, though it most likely had its roots in the amateur astronomy boom of the 1970s and was a fixture of many astronomy clubs by the 1980s. There are no Messier objects located between right ascension 21 hours 40 minutes and 23 hours 20 minutes, and only one (M52) between 23 hours 20 minutes and 0 hours 40 minutes. With the Sun reaching the “0 hour” equinoctial point on the March Vernal Equinox (falling on March 20^th as reckoned in Universal Time for the next decade), all of the Messier objects are theoretically observable in one night around early March to early April. Taking into account for the New Moon nearest to the March equinox, the best dates for a weekend Messier marathon for the remainder of the decade are as follows;

Optimal Messier marathon dates for the remainder of the decade. (Compiled by author).

Note that this year’s weekend is very nearly the earliest that it can occur. The optimal latitude for Messier marathoning is usually quoted as 25° north, about the latitude of Miami. It’s worth noting that 2013 is one of the very few years where the primary weekend falls on or before our shift one hour forward to Daylight Saving time, occurring this year on March 10^th for North America.

Students of the Messier catalog will also know of the several controversies that exist within the list. For example, one wide double star in Ursa Major made its way into the catalog as Messier 40. There’s also been debate over the years as to the true identity of Messier 102, and most marathoners accept the galaxy NGC 5866 in its stead. Optics of the day weren’t the most stellar (bad pun intended) and this is evident in the inclusion of some objects but the omission of others. For example, it’s hard to imagine a would-be comet hunter mistaking the Pleiades (M45) for an icy interloper, but curiously, Messier omits the brilliant Double Cluster in Perseus.

M42, the Orion Nebula. (Photo by Author, taken back in the days of ye ole film!)

It’s vital for Messier marathoners to run through objects in proper sequence. Most visual observers run these in groups, although Alex McConahay suggests in a recent April 2013 Sky & Telescope article that folks running a photographic marathon (see below) beware of wasting precious time crossing the celestial meridian (a maneuver which requires a telescope equipped with a German Equatorial mount to “flip” sides) hunting down objects. The unspoken “code of the skies” for visual Messier marathoners is that “Go-To” equipped scopes are forbidden. Part of the intended purpose of the exercise is to acquaint you with the night sky via star hopping to the target.

Most observers complete Messier objects in groups. You’ll want to nab M77 and M74 immediately after local dusk, or the marathon will be over before it starts. You’ll then want to move over to the Andromeda Galaxy and the collection of objects in its vicinity before scouring Orion and environs. From that point out, you can begin to slow down a bit and pace yourself through the galaxy groups in Coma Berenices and the Bowl of Virgo asterism. Another cluster of objects stretch out in the sky past midnight along the plane of our Milky Way Galaxy from Sagittarius to Cygnus, and the final (and often most troublesome) targets to bag are the Messier objects in Aquarius and M30 in Capricornus just before dawn. Remember, dark skies, warm clothes, and hot coffee are your friends in this endeavor!

There have been alternate rules or versions of Messier marathons over the years. Some imagers complete one-night photographic messier marathons. There are even abbreviated or expanded versions of the feat. It is also possible to nab most of the Messier catalog with a good pair of binoculars under clear skies. Probably the most challenging version we’ve heard of is sketching all 110 Messier objects in one evening… you might be forgiven for using a Go-To enabled telescope to accomplish this!

Finally, just like running marathons, the question we often get is why. Some may eschew transforming the art of dark sky observing into a task of visual gymnastics. We feel that to run through this most famous of catalogs in an evening is a great way to learn the sky and practice the fast-disappearing art of star hopping. And hey, no one’s saying you can’t take a year or three to finish the Messier catalog… its a big universe, and the New General Catalog (NGC) and Index Catalog (IC) containing thousands of objects will still be waiting. Have YOU seen all 110?

– A perpetual listing of Messier marathon visibility by latitude by Tom Polakis.

– An All Sky Map of the Messier catalog.

– A handy priority list for a Messier marathon compiled by Don Machholz.

March 5, 2013December 23, 2015 by Ken Kremer

Feel the Power of a Mighty Falcon 9 Blast Off Creaming Cameras

Remote cameras set up for Falcon 9 SpaceX CRS-2 launch on March 1, 2013. Credit: Ken Kremer/www.kenkremer.com

Video: Launch of SpaceX Falcon 9 on CRS-2 mission on March 1, 2013 from Cape Canaveral, Florida. Credit: Jeff Seibert/Mike Barrett/Wired4Space.com

Have you ever wondered what it would be like to be standing at the base of a launch pad when a powerful rocket ignites for the heavens?

It’s a question I get from many kids and adults.

So check out the fabulous video from my friends Mike Barrett and Jeff Seibert- and feel the power of the mighty SpaceX Falcon 9 which just rocketed to space on March 1 from Space Launch Complex 40 on Cape Canaveral Air Force Station, Florida.

Mike and Jeff set up a series of video recorders distributed around the Falcon 9 Launch Pad – for a ‘You Are There’ experience.

Well although you’d enjoy the awesome view for a split second, the deafening sound and fury would certainly drive you mad, and then leave you dead or vegetabilized and wishing you were dead.

The cameras get creamed in seconds with mud, soot and ash.

How is this view possible?

Those of us media folks lucky enough to cover rocket launches, usually get to visit around the pad the night before to view the behemoths up close – after they are rolled out and unveiled for liftoff.

We also have the opportunity to set up what’s called “remote cameras” spaced around the pad that take exquisite images and videos from just dozens of yards (meters) away – instead of from ‘safe’ distance a few miles (km) away.

The cameras can be triggered by sound or timers to capture up close sounds and sights we humans can’t survive.

After a shaky start, the SpaceX Dragon cargo resupply capsule launched atop the Falcon 9 safely docked at the International Space Station on Sunday, March 3.

The SpaceX CRS-3 flight is slated to blast off sometime during Fall 2013

Maybe we’ll see you there !

Ken Kremer

Falcon 9 SpaceX CRS-2 launch on March 1, 2013 to the ISS from Cape Canaveral, Florida.- shot from the roof of the Vehicle Assembly Building. Credit: Ken Kremer/www.kenkremer.com

Dave Dickinson & Ken Kremer; reporting live for Universe Today from Space Launch Complex 40, Cape Canaveral Florida, on the SpaceX Falcon 9 CRS-2 mission - posing with Falcon 9 rocket in horizontal position at pad prior to March 1, 2013 liftoff. Credit: Ken Kremer/www.kenkremer.com — Dave Dickinson & Ken Kremer; reporting live for Universe Today from Space Launch Complex 40, Cape Canaveral Florida, on the SpaceX Falcon 9 CRS-2 mission – posing with Falcon 9 rocket in horizontal position at pad prior to March 1, 2013 liftoff. Rocket exhaust blasts out of the concrete Flame Trench at right. Credit: Ken Kremer/www.kenkremer.com

March 5, 2013December 23, 2015 by Nancy Atkinson

Curiosity Rover Recovering From Computer Glitch

This self-portrait of NASA's Mars rover Curiosity combines 66 exposures taken by the rover's Mars Hand Lens Imager (MAHLI) during the 177th Martian day, or sol, of Curiosity's work on Mars (Feb. 3, 2013). Image credit: NASA/JPL-Caltech/MSSS

The Curiosity rover is now out of “safe mode” following a memory problem with its main computer, and the Mars Science Laboratory team expects the rover to resume full operations next week. Controllers switched the rover to a redundant onboard computer, the rover’s “B-side” computer, on Feb. 28 when the “A-side” computer that the rover had been using demonstrated symptoms of a corrupted memory location. The intentional computer swap put the rover, as anticipated, into minimal-activity safe mode.

“We are making good progress in the recovery,” said MSL Project Manager Richard Cook. “One path of progress is evaluating the A-side with intent to recover it as a backup. Also, we need to go through a series of steps with the B-side, such as informing the computer about the state of the rover — the position of the arm, the position of the mast, that kind of information.”

This is the first glitch of any kind the Curiosity rover has suffered since landing in August, 2012. NASA has indicated this is not a serious problem (as Emily Lakdawalla of the Planetary Society put it “not life-threatening, just really inconvenient.) It will just take time to make sure the computer switch-over is done correctly.

NASA says the cause for the A-side’s memory symptoms observed last week remains to be determined, but the most likely cause was that the computer memory was corrupted by a cosmic ray hit. These are subatomic particles traveling through space at extraordinary speeds. The origin of cosmic rays was recently determined to be distant supernovae.

Meanwhile, the rover has not done any surface operations or uploaded any new images to Earth since Sol 200, so for those of you going through withdrawal from not seeing any new raw images from Curiosity, we’ll keep you posted of when the flow of images resumes.