Astronomy Archives

February 21, 2009December 24, 2015 by Anne Minard

Arizona Scientist: We Could All Be Martians

Artist's conception of an fragment as it blasts off from Mars. Boulder-sized planetary fragments could be a mechanism that carried life between Mars and Earth, UA planetary scientist Jay Melosh says. (Credit: The Planetary Society)

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As long as we’re still pondering human origins, we may as well entertain the idea that our ancestor microbes came from Mars.

And Jay Melosh, a planetary scientist from the University of Arizona in Tucson, is ready with a geologically plausible explanation.

Meteorites.

“Biological exchange between the planets of our solar system seem not only possible, but inevitable,” because of meteorite exchanges between the planets, Melosh said. “Life could have originated on the planet Mars and then traveled to Earth.”

jay_melosh — Jay Melosh. Credit: Maria Schuchardt, University of Arizona Lunar and Planetary Lab

Melosh is a long-time researcher who says he’s studied “geological violence in all its forms.” He helped forge the giant impact theory of the moon’s formation, and helped advance the theory that an impact led to the extinction of the dinosaurs 65 million years ago.

He points out that Martian meteorites have been routinely pummeling Earth for billions of years, which would have opened the door for past Mars microbes to hitch a ride. Less regularly, Earth has undergone impacts that sent terrestrial materials flying, and some of those could have carried microbes toward the Red Planet.

“The mechanism by which large impacts on Mars can launch boulder-sized surface rocks into space is now clear,” he said. He explained that a shock wave spreads away from an impact site faster than the speed of sound, interacting with the planetary surface in a way that allows material to be cast off – at relatively low pressure, but high speed.

“Lightly damaged material at very high speeds,” he said, “is the kind of environment where microorganisms can survive.”

Scientists have recent evidence of Earth microbes surviving a few years in space. When the Apollo 12 astronauts landed on the moon, they retrieved a camera from Surveyor 3, an unmanned lander that had touched down nearly three years prior. Earthly microbes – including those associated with the common cold — were still living inside the camera box.

“The records were good enough to show one of the technicians had a cold when he was working on it,” he said.

Scientists also have evidence that microbes can survive for thousands or even hundreds of thousands of years when frozen on Earth, but surviving that long in space would be an entirely different matter, with the bombardment of UV light and cosmic rays. Then again, the microbe Dienococcus radiodurans is known to survive in the cores of nuclear reactors.

Melosh acknowledges that scientists lack proof that such an exchange has actually occurred between Mars and Earth — but science is getting ever closer to being able to track it down.

LEAD PHOTO CAPTION: Artist’s conception of an fragment as it blasts off from Mars. Boulder-sized planetary fragments could be a mechanism that carried life between Mars and Earth, UA planetary scientist Jay Melosh says. (Painting by Don Davis. Copyright SETI Institute, 1994)

Source: University of Arizona and an interview with Jay Melosh

February 21, 2009December 24, 2015 by Tammy Plotner

Tunnel Vision – Step Into the “Ring”…

M7n Parallel Vision by Jukka Metsavainio

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Who doesn’t recognize this awesome image of Messier Object 57 which was taken by the Hubble Space Telescope? The original color image was assembled from three black-and-white photos taken through different color filters with the Hubble’s Wide Field Planetary Camera 2. We know the blue filtration isolates emission from very hot helium, which is located primarily close to the hot central star… just as green represents the further away ionized oxygen and cool red shows ionized nitrogen gas at the farthest position of all. We know where they’re supposed to be, but we’ve never quite seen it in dimension until it’s been visualized by the “magic” of Jukka Metsavainio…

Like all our our “stereo” image produced for UT by Jukka Metsavainio, two versions are presented here. The one above is parallel vision – where you relax your eyes and when you are a certain distance from the monitor screen the two images will merge into one to produce a 3D version. I have heard from a friend recently that if you place a card in the center of the image with the edge towards you, it aids in seeing the parallel version. (And he was right.) The second – which appears below – is crossed vision. This is for those who have better success crossing their eyes to form a third, central image where the dimensional effect occurs. (The card “trick” also works well here, too!) Jukka’s visualizations of what Hubble images would look like if we were able to see them in dimension come from studying the object, its known field star distances and the different wavelengths of light. Are you ready to “cross” the boundary and step into the “Ring” for another round with Messier 57? Then let’s rock…

Originally discovered by discovered by Antoine Darquier de Pellepoix in January, 1779 and independently found by Charles Messier later that same month, it was Darquier who first said that it was “…as large as Jupiter and resembles a planet which is fading.” Thanks to his description, the term ” planetary nebula” stuck because of their similarity in appearance to giant planets when viewed through small optical telescopes. However, Sir William Herschel wasn’t quite so aperture limited, and he was the first to propose this new object was a nebula was formed by multiple faint stars. By 1800, Count Friedrich von Hahn had discovered M57’s central star and within 64 years William Huggins was studying its spectral signature. Just a blink of a cosmic eye later, another 22 years, Hungarian astronomer Jen? Gothard had discovered it had a planetary nebula nucleus.

What has remained constant over the years is the classic bipolar structure associated with the “Ring” nebula – a prolate spheroid with strong concentrations of material along its equator. Its symmetrical structure is one of the best known in the night sky – right down to the knots along the edges that can often be observed with larger telescopes. What exactly are they? According to C.R. O’Dell (et al); ” The equator of the Ring Nebula is optically thick and much denser than the optically thin poles. The inner halo surrounding NGC 6720 represents the pole-on projection of the AGB wind at high latitudes (circumpolar) directly ionized by the central star, whereas the outer, fainter, and circular halo is the projection of the recombining AGB wind at mean to low latitudes, shadowed by the main nebula. The spatio-kinematical properties of the Ring Nebula and the origin of the dense knots commonly observed in late-stage planetary nebulae are critically compared with the predictions of radiation-hydrodynamic and wind interaction models.”

These winds, bubbles and explosions were part of the original Hubble photograph where our visualization came from. “We have studied the closest bright planetary nebulae with the Hubble Space Telescope’s WFPC2 in order to characterize the dense knots already known to exist in NGC 7293.” says O’Dell, “We find knots in all of the objects, arguing that knots are common, simply not always observed because of distance. The knots appear to form early in the life cycle of the nebula, probably being formed by an instability mechanism operating at the nebula’s ionization front. As the front passes through the knots they are exposed to the photoionizing radiation field of the central star, causing them to be modified in their appearance. This would then explain as evolution the difference of appearance like the lacy filaments seen only in extinction in IC 4406 on the one extreme and the highly symmetric “cometary” knots seen in NGC 7293. The intermediate form knots seen in NGC 2392, NGC 6720, and NGC 6853 would then represent intermediate phases of this evolution.”

Anyone who is willing to step into the ring with this champion of all planetary nebulae is liable to end up with a few knots somewhere! Enjoy your tunnel vision journey….

February 21, 2009December 24, 2015 by Anne Minard

NASA Delays Discovery Launch Fourth Time

The space shuttle Discovery moved to the Kennedy Space Center Launch Pad on Jan. 14, but launch has been postponed until further notice. Credit: NASA/Troy Cryder

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NASA announced yet another delay for the launch of the Discovery STS-119 mission to the International Space Station Friday, marking the fourth time the mission has been postponed.

An all-day review of the craft’s readiness for launch left managers still under-confident about the operations of three hydrogen control valves that channel gaseous hydrogen from the main engines to the external fuel tank. Engineering teams have been working to identify what caused damage to a flow control valve on shuttle Endeavour during its November 2008 flight. NASA managers decided Friday more data and possible testing are required before launch can proceed.

“We need to complete more work to have a better understanding before flying,” said Bill Gerstenmaier, associate administrator for Space Operations at NASA Headquarters in Washington. Gerstenmaier chaired Friday’s Flight Readiness Review.

“We were not driven by schedule pressure and did the right thing. When we fly, we want to do so with full confidence.”

306355main_hatch-m_800-600 — The STS-119 crew members gather in front of the hatch into space shuttle Discovery to place the mission plaque. Standing from left are Mission Specialists Joseph Acaba, Koichi Wakata, Steve Swanson, John Phillips and Richard Arnold and Pilot Tony Antonelli. Kneeling in front is Commander Lee Archambault. Photo credit: NASA/Kim Shiflett January 20, 2009

Besides understanding what happened with Endeavor’s valves last fall, teams also have tried to determine the consequences if a valve piece were to break off and strike part of the shuttle and external fuel tank.

Meanwhile, the Discovery launch date has shifted from Feb. 12, to Feb. 19, to Feb. 22, Feb. 27 and now — as of last night’s briefing — is postponed until further notice. The Space Shuttle Program has been asked to develop a plan for further inspections. The plan will be reviewed during a meeting on Wednesday, Feb. 25 and a new target launch date may be considered then.

The STS-119 mission is supposed to enhance the solar gathering power of the International Space Station so it might support a larger crew. When it does fly, STS-119 will tote two solar array wings, each of which has two 115-foot-long arrays, for a total wing span of 240 feet, including the equipment that connects the two halves and allows them to twist as they track the sun. Altogether, the four sets of arrays can generate 84 to 120 kilowatts of electricity – enough to provide power for more than 40 average homes.

The mission astronauts arrived at the Kennedy Space Center Jan. 19 and have more or less been in standby mode ever since, shuttling back and forth between Florida and the Johnson Space Center in Houston. On Wednesday of this week, STS-119 mission specialists Richard Arnold and Joseph Acaba were in the Neutral Buoyancy Laboratory at Johnson, brushing up on spacewalk procedures. As of Thursday, the astronauts were in launch-countdown mode which included preflight quarantine.

February 20, 2009December 24, 2015 by Tammy Plotner

GLOBE at Night 2009 – Can You See the Stars?

Turning out the lights for “Earth Hour” is going to be a great way to demonstrate caring about climate changes by turning off the lights – but what about the impact that light pollution has on our skies? 2008 marked a monumental shift in human history when the number of people living in cities exceeded half the people on Earth. Because of the ambient light of urban landscapes, many city dwellers have never seen a sky full of stars. Are you interested in helping science study the impact of lighting in your area? Then step inside and learn more about GLOBE…

GLOBE at Night is a wonderful way for everyone around the world to participate as a citizen-sciencist to raise public awareness of the impact of artificial lighting on local environments. This event encourages everyone – students, educators, dark sky advocates and the general public – to measure the darkness of their local skies and contribute their observations online to a world map. GLOBE at Night is a centerpiece of the Dark Skies Awareness Global Cornerstone Project for the International Year of Astronomy (IYA) in 2009, and we need people – just like you – to get involved! Data collection and online reporting is simple and user-friendly.

Led by the educational outreach staff at the National Optical Astronomy Observatory and the University Corporation for Atmospheric Research GLOBE Program, the GLOBE at Night campaign will take place for a 4th year from March 16-28, 2009. “The geographic reach of the GLOBE at Night program exceeded our wildest expectations,” said Connie Walker, an astronomer and science education specialist at the National Optical Astronomy Observatory (NOAO), one of the event’s major co-sponsors. “We fell a few hundred short of our target of 5,000 total observations, but the engagement and excitement of large family groups, and dozens of school children participating in the activity together, more than make up for a few less data points.”

Over the past 3 years, tens of thousands of citizen-scientists around the world have contributed measurements of their local sky brightness to a growing global database in two ways: simple unaided-eye observations toward the constellation Orion and quantative digital measurements through a handheld, well-calibrated sky-brightness meter. For the first method, citizen-scientists take data on light pollution levels by comparing what they see toward Orion, with star maps showing different stellar brightness limits. The basic idea is to look for the faintest stars and match them to one of seven star maps of progressively fainter limiting magnitudes. For the second method, digital sky-brightness meters are used for more precise measurements. The low-cost digital Sky Quality Meters (SQMs), manufactured by Unihedron, can make a highly repeatable, direct measurement of integrated sky brightness. The newly available second-generation of SQM-Ls being used this year by several GLOBE at Night sites has a cone-shaped “field of view” that is three times more narrow than the older model. This specifically aids its use in city environments, where surrounding lights or buildings may affect the readings.

To learn the five easy steps to participate in either type of GLOBE at Night program and to obtain important information on light pollution, stellar magnitudes, the mythology of Orion, how to find Orion, how to obtain your latitude and longitude, and how to use an SQM, see the GLOBE at Night website. No prior experience is necessary and all the information you need to participate is right there – along with downloads for activity kits for families, teachers and invididuals in six different languages. All observations will be available online via Google Earth and as downloadable datasets, too.

Thanks to an international network of partners, GLOBE reaches people around the world, and during their first two years managed 20,000 observations from a total of 100 countries. This year, they’re hoping for an even greater success rate and within weeks of submitting your data, a world map showing the results of your studies will be made available. Using this information, you can then compare the data to previous studies, as well as satellite data and population density data. Collecting information from mulitple locations inside a single city or region is highly encourged, and would make a great class project or astronomy club activity!

By activity participating in projects like GLOBE, you can make difference. More measurements made each year and over the next few years will allow for in more depth analysis. More measurements within a city will provide maps of higher resolution and comparisons between years would allow people to monitor changes. Just like our other Earthly environments, monitoring our lighting environment will allow us as citizen-scientists to identify and preserve dark sky locations in cities or catch an area developing too quickly and influence people to make smart choices in lighting by providing them with informed neighbors. As just everyday, ordinary people, we can impact what happens by educating ourselves and others. If more and more people took a few minutes during the March 2009 campaign to measure sky brightness either toward Orion with the unaided-eye or toward zenith with a Sky Quality Meter (or both!), their measurements – and yours – will make a world of difference!

Many thanks to NOAO team members, Constance E. Walker, Douglas Isbell, Stephen M. Pompea, David A. Smith and Thomas R. Baker.

February 20, 2009December 24, 2015 by Anne Minard

Sweet Potatoes Flew into Space Aboard Columbia

Sweet potato cuttings grown in an Alabama laboratory were flown aboard Columbia to test root growth in microgravity. Courtesy of NASA.

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A team of researchers from the Deep South sent sweet potato plants into space, as part of an experiment aimed at providing food for long-term space missions.

Desmond G. Mortley, from the G.W. Carver Agricultural Experiment Station at Alabama’s Tuskegee University, and his colleagues launched the sweet potato cuttings on a five-day mission aboard the space shuttle Columbia, and compared their success to ground-based cuttings at Kennedy Space Center in Florida.

“The intent of the experiment was to study if stem cuttings would be a successful means of propagating plants in space, just as they are on Earth,” said Raymond Wheeler, a study co-author from NASA’s Biological Science Office at the Kennedy Space Center. “The results showed that the cuttings did indeed produce adventitious roots in microgravity, suggesting that cuttings should work well in space settings.”

The sweet potato experiment was flown on Columbia’s July 1999 mission to the Chandra X-Ray Observatory. The study findings were published in the May 2008 issue of the Journal of American Society for Horticultural Science, although a public press release was issued just this week.

Seeds of several crops have been grown in microgravity, but this was the first test for plants grown from cuttings. Cuttings grow roots faster than seeds do, and sweet potato cuttings regenerate very easily. This made them ideal for the study.

According to the study authors, all of the cuttings produced roots and growth was “quite vigorous in both ground-based and flight samples.” Except for a slight browning of some root tips in the flight samples, all of the stem cuttings appeared normal, they added. The roots on the flight cuttings tended to grow in random directions, sometimes perpendicular to the stems. Also, stem cuttings grown in microgravity had more roots and longer roots than ground-based controls.

The next step, Mortley and his colleagues say, will be to experiment over longer space missions to test root cuttings’ ability to grow plants.

Source: Eurekalert and Journal of American Society for Horticultural Science.

February 20, 2009December 24, 2015 by Tammy Plotner

Weekend SkyWatcher’s Forecast – February 20-22, 2009

Greetings, fellow SkyWatchers! Are you ready for one awesome weekend? Then let’s enjoy the dark skies as we take on a wide variety of challenges. For those who just use their eyes, this is a great time to spot Venus, Saturn, Jupiter and the New Moon in the Old Moon’s Arms. Need more? For binoculars we have open star clusters and bright comets. Still more? Then get out your telescope and dust off your eyepieces and let’s see how good you are as we take on some challenges! Whenever you’re ready, I’ll see you in the back yard….

Friday, February 20, 2009 – On this date in 1962, John Glenn was rocketing around Earth on his first orbit as our friends ‘‘down under’’ made history. Residents of Perth, Australia, simultaneously switched on lights as Glenn flew over—the first city spotted from space! If you’re out tonight as the Sun sets, be sure to take a look along the western horizon for the first bright “star” to appear. That’s not a star – that’s Venus! Today in 1996 also marks the discovery of Sakurai’s Object, a star in collapse.While studying Sagittarius and photographing what appeared to be a typical nova, Yukio Sakurai became only the third twentieth-century astronomer to witness a star in final helium flash. When this occurs, the star is switching its nuclear fuel from hydrogen to helium and then burning the helium to carbon in the final stage, burping forth an envelope from its interior.

Let’s examine an open cluster where stars have gone through this same evolutionary step. Begin by identifying Delta Geminorum and hop a fist-width east for open cluster NGC 2420 (RA 07 38 23 Dec +21 34 24). This magnitude 8.5 group is visible under dark-sky conditions to binoculars as a weak, round, hazy patch and requires a mid-sized telescope to begin resolution of its long, looping chains of stars.

Some members are similar to Sakurai’s Object, while others have evolved to helium depletion. Studying clusters like NGC 2420 is important: they are areas where stars are all about the same age, yet their different masses mean they evolve at different rates. Average telescopes will only see the primary stars, while large aperture notices the distinct glow of hundreds of stars on the verge of resolution. If you get the impression of a weak globular cluster, you’d be correct. With a thousand members packed into a
30-light-year sphere, a lot has happened during its 1.7-billion-year lifetime. It may have started in our own galaxy’s cluster-forming region and been thrown clear by an encounter with a large mass. Or, it might have once been part of a smaller galaxy absorbed by our own. But one thing is clear: its unusual Sun-like elements—so far from where they belong—make NGC 2420 a prime playground for study. Some of its members could even be blue stragglers—unions of two stars into one!

Saturday, February 21, 2009 – This day in 1972, Luna 20 made a safe touchdown in the Apollonius highlands, where it captured 30 grams of surface material to return to Earth. The Moon will make a very scenic appearance in the pre-dawn skies and be visible for several hours after the Sun rises. Take time to show others its position as you walk to work or school, and explain its movement away from the Sun from our viewpoint. How long does the Moon remain visible as the sky brightens? This pretty visage is often called the “New Moon in the Old Moon’s Arms”.

Got comet? Well, why the heck not? If you thought Comet Lulin was easy to find a week ago, it’s even easier to find now. The chart you see here was generated for position for the morning of Friday, February 20th – and Lulin will continue its course towards a future rendezvous with Saturn on Monday, February 23rd. With almost no Moon to contend with in the early morning sky (and if you get up early enough, you can easily observe before the Moon rises), 6th magnitude C/2007 N3 is so close to being visible to the unaided eye that even the smallest of binoculars will pick this elongated round fuzzy right out of the sky. Don’t wait until it meets up with Saturn to take a look at this 38 million mile traveler from the Oort Cloud – instead, try tracking it for several days. Lulin is sufficiently bright enough to been seen even from an urban setting and the bright “guide posts” of Spica and Saturn are easy markers.

Tonight we’ll study an object of many names: Melotte 25, Collinder 50, and Caldwell 41, a star cluster so bright it doesn’t require a telescope. At 150 light-years away, the Hyades is the nearest gathering of stars to our Solar System that can be seen as a cluster. So, where is it? First, look at Aldebaran…

With the exception of this 60-light year-distant orange giant, almost all the stars around it are moving toward a point slightly east of Betelgeuse. The 790 million-year-old central mass spreads over a 10 light-year area, while outlying stars could stretch as far as 80 light-years. Aim binoculars its way and be blown away by a rich field of stars! Even with minimum magnification you’ll split the brightest member of the Hyades, the twin Sigma pair. They’ll appear close to the same magnitude and distance to the eye, but only the northernmost belongs to the Hyades moving cluster. Power up with a telescope. You’ll discover a wealth of other doubles and delightful color combinations in this much under-visited treat!

Now, I’ll appeal to the more advanced stargazer. Begin at the border of Orion and locate 8 Monoceros. We’re hunting for an odd star cluster called Dolidze 22 (RA 06 23 06 Dec +04 40 55). Although there’s no great scientific reason to observe this sparse open cluster, it’s an exercise aimed at sharpening your skills. To date, no data exist on the cluster’s true distance or age.

When you’ve noted your study, move about 2 degrees south and identify Collinder 91 (RA 06 21 42 Dec +02 22 00). Again, a loose, star-poor collection, essentially unstudied except for association. Why choose these two objects instead of brighter ones? Learning to visually understand a group relationship among stars is a skill Sir William Herschel had naturally, but one that can only be developed by most of us with a lot of practice. As Herschel once said:

‘‘The phenomena of nature, especially those that fall under the inspection of the astronomer, are to be viewed not only with the usual attention to facts as they occur, but with the eye of reason and experience.’’

Sunday, February 22, 2009 – If you’re up before dawn, look for the relatively close pairing of the waning Moon and Jupiter. Try using the Moon’s position to see how long you can still spot the bright planet as the sky turns blue!

When the Sun has risen, salute the 1824 birth of Pierre Janssen, the first to devise a method for observing solar prominences. With a spectroscope, he proved the solar chromosphere is gaseous in nature and reported a helium spectral line. Janssen was also the first to record surface granulation via photography and published his own illustrated solar atlas in the year 1904.

In 1966, Kosmos 110 launched its canine crew, Veterok and Ugolyok, into space history. Tonight let’s look at a celestial dog as we turn to Canis Minor. A large portion of the constellation is only viewable from the Southern Hemisphere, and most of its brighter stars hide below the horizon for the north. Look for an arch of four fairly bright stars to the east of Canis Major. The second from the east is Xi Puppis. Aim telescopes or binoculars just north of Xi (RA 07 44 36 Dec -23 52 00) for M93.

This bright open cluster is a rich concentration of stars of various magnitudes, which explodes in sprays of stellar fireworks in the eyepiece of a large telescope. Spanning 18–22 light-years and residing 3,400 light-years away, M93 contains blue giants and lovely golds. Janssen would have been very proud to know it’s been studied spectroscopically and contains many Sun-like stars! M93 is the last object personally discovered by Messier, who described it as ‘‘A cluster of small stars without nebulosity.’’ Did he realize that the light left during the reign of Ramses III? Or that this celestial gathering was 100 million years old? Did Messier realize it was forming about the time Earth’s landmasses were breaking up, dinosaurs ruled, and the first mammals and birds were evolving? Although H.G. Wells’ The Time Machine is a work of fiction (published on this date in 1895), each time we view light through a telescope we take a journey back across time itself.

Now, let’s time-travel back 5,000 years as we head for NGC 2392. Located about two fingerwidths southeast of Delta Geminorum (RA 07 29 10 Dec +20 54 42), this beauty is a planetary nebula commonly known as the ‘‘Eskimo.’’ Discovered in 1787 by Sir William Herschel, a small telescope will see it as a fuzzy green star, while aperture will reveal definite annulus around its central stellar point. A steady night helps to reveal details, and a nebula filter lights it up! NGC 2392 is so complex that it is not yet fully understood. We know the glowing gases are the outer layers of its central star, shed 10,000 years ago, while the inner ribbons of light (called filaments) are areas where particles are being pushed away by the strong stellar wind. Even now, we still can’t quite explain the unusual outer filaments! It won’t look like a Hubble image in your telescope, but you can still marvel at a unique mystery—seeing its light as it was when the first ‘‘physicists’’ began using the first ‘‘computer’’—the newly invented abacus!

Now, don’t forget… Before the dawn arrives, Comet Lulin will meet with Saturn! Because the comet doesn’t stop moving and we all live in different time zones, the position will be slightly different for each observer around the world, but the Universal Date you’ve been waiting for is about to happen….

Until next week? Dreams really do come true when you keep on reaching for the stars!

This week’s awesome images are: Sakurai’s Object (press release photo), NGC 2420 (credit—Palomar Observatory, courtesy of Caltech), New Moon in Old Moon’s Arms – Jarle Aasland (APOD), Comet Locator Chart (credit – Chris Peet, courtesy of Heavens-above.com), Illustration of the Hyades Cluster (generated image), Area of Sigma 1 and Sigma 2 Tauri (credit—Palomar Observatory, courtesy of Caltech), Dolidze 22 and Collinder 91 (credit—Palomar Observatory, courtesy of Caltech), Pierre Janssen (historical image), M93 (credit—Palomar Observatory, courtesy of Caltech) and NGC 2392 (credit—Hubble Space Telescope). We thank you so much!

February 19, 2009December 24, 2015 by Anne Minard

NASA’s Kepler Mission Ready for Launch

Technicians working inside the Astrotech Space Operations facility near NASA's Kennedy Space Center look over the Kepler spacecraft soon after it arrived in Florida in preparation for launch. Image credit: NASA/Tim Jacobs

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NASA’s Kepler spacecraft is ready to be moved to the launch pad today and will blast off within weeks, with a mission to address an age-old question: Are we alone?

Kepler is scheduled to blast into space from Florida’s Cape Canaveral Air Force Station aboard a Delta II rocket on March 5 at 10:48 p.m. eastern time (7:48 p.m. Pacific). It is the first mission with the ability to find planets like Earth — rocky planets that orbit sun-like stars in a warm zone where liquid water could be maintained on the surface. If Earth-sized and slightly larger planets are as common around other stars as some astronomers suspect, Kepler could spy hundreds of them within the next few years.

If so, “life may well be common throughout our universe,” said William Borucki, NASA’s principal investigator for Kepler science, who spoke about the mission Thursday afternoon at a NASA press conference. “If on the other hand we don’t find any, that will be another profound discovery. In fact it will mean there will be no Star Trek.”

The Kepler mission will spend three and a half years surveying more than 100,000 sun-like stars in the Cygnus-Lyra region of our Milky Way galaxy. Its telescope is specially designed to detect the periodic dimming of stars that planets cause as they pass by. Some star systems are oriented in such a way that their planets cross in front of their stars, as seen from our Earthly point of view. As the planets pass by, they cause their stars’ light to slightly dim, or wink.

The telescope can detect even the faintest of these winks, registering changes in brightness of only 20 parts per million. To achieve this resolution, Kepler will use the largest camera ever launched into space, a 95-megapixel array of charged couple devices, known as CCDs.

“If Kepler were to look down at a small town on Earth at night from space, it would be able to detect the dimming of a porch light as somebody passed in front,” James Fanson, Kepler project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a press release. During the briefing he added that the resolution is “akin to measuring a flea as it creeps across the headlight of an automobile at night. That’s the level of precision we have to achieve.”

Fanson added that Kepler, at a cost of about $500 million, is “the most complex piece of space flight hardware ever built” by the Boulder, Colorado-based Ball Aerospace & Technologies Corp.

The exoplanet research field has already proven exciting, Borucki said. Just over three hundred exoplanets have been detected so far, most of them gas giants like Jupiter and Saturn because those are the easiest to spot with pre-Kepler instruments. Already, the known exoplanets are an eclectic bunch.

“We’re finding planets that [would] float like foam on water,” Borucki said. “We’re finding planets with the density of lead.” And whereas researchers were expecting planet with orderly, circular orbits and sizes that increased with distances from stars, they’re finding a chaotic mix of behaviors — eccentric orbits, and giant, gaseous worlds so close to their parent stars that they complete full orbits within days.

By staring at one large patch of sky for the duration of its lifetime, Kepler will be able to watch planets periodically transit their stars over multiple cycles, allowing astronomers to confirm the presence of planets and use the Hubble and Spitzer space telescopes, along with ground-based telescopes, to characterize their atmospheres and orbits. Earth-size planets in habitable zones would theoretically take about a year to complete one orbit, so Kepler will monitor those stars for at least three years to confirm the planets’ presence.

The first objects likely to be reported will be the Jupiter- and Saturn-sized planets, and gradually — as confirmations roll in and detections get more focused — Neptune and then Earth-sized detections will be more likely to emerge, said exoplanet hunter Debra Fischer of San Francisco State University in California, who is not directly involved with the mission.

“We have a good chance of finding Mars-size planets, and a possibility of finding Mercury-sized planets” with Kepler, she said. “We don’t think we can do better than that.”

The scientists are in no rush to announce new discoveries until they’re “bulletproof,” they said — which could translate into years of suspense for the world’s Trekkies.

“We don’t want to have false discoveries,” Borucki said. “We want to be sure when we say it’s an earth, its an earth.”

Source: NASA teleconference and press release.

February 19, 2009December 24, 2015 by Anne Minard

Fermi Glimpses Wildest-Ever Gamma-Ray Blast

GRB 080916C’s X-ray afterglow appears orange and yellow in this view that merges images from Swift’s UltraViolet/Optical and X-ray telescopes. Credit: NASA/Swift/Stefan Immler

Researchers using the Fermi Gamma-ray Space Telescope are reporting a gamma-ray explosion that blows away anything they’ve seen before. The blast, recorded last fall in the constellation Carina, released the energy of 9,000 supernovae.

The collapse of very massive stars can produce violent explosions, accompanied by strong bursts of gamma-ray light, which are some of the brightest events in the universe. Typical gamma-ray bursts emit photons with energies between 10 kiloelectron volts and about 1 megaelectron volt. Photons with energies above megaelectron volts have been seen in some very rare occasions but the distances to their sources were not known. An international research consortium is reporting in this week’s issue of the journal Science Express that the Fermi Gamma-Ray Space Telescope has detected photons with energies between 8 kiloelectron volts and 13 gigaelectron volts arriving from the gamma-ray burst 080916C.

formerly_glast — Fermi, formerly known as GLAST, pictured pre-launch in the spring of 2008. Photo credit: NASA/Dimitri Gerondidakis

The explosion, designated GRB 080916C, occurred just after midnight GMT on September 16 (7:13 p.m. on the 15th in the eastern US). Two of Fermi’s science instruments — the Large Area Telescope and the Gamma-ray Burst Monitor — simultaneously recorded the event. Together, the two instruments provide a view of the blast’s gamma-ray emission from energies ranging from 3,000 to more than 5 billion times that of visible light.

A team led by Jochen Greiner at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, established that the blast occurred 12.2 billion light-years away using the Gamma-Ray Burst Optical/Near-Infrared Detector (GROND) on the 2.2-meter (7.2-foot) telescope at the European Southern Observatory in La Silla, Chile.

“Already, this was an exciting burst,” says Julie McEnery, a Fermi deputy project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “But with the GROND team’s distance, it went from exciting to extraordinary.”

Astronomers believe most gamma-ray explosions occur when exotic massive stars run out of nuclear fuel. As a star’s core collapses into a black hole, jets of material — powered by processes not yet fully understood — blast outward at nearly the speed of light. The jets bore all the way through the collapsing star and continue into space, where they interact with gas previously shed by the star. This generates bright afterglows that fade with time.

The burst is not only spectacular but also enigmatic: a curious time delay separates its highest-energy emissions from its lowest. Such a time lag has been seen clearly in only one earlier burst, and researchers have several explanations for why it may exist. It is possible that the delays could be explained by the structure of this environment, with the low- and high-energy gamma rays “coming from different parts of the jet or created through a different mechanism,” said Large Area Telescope Principal Investigator Peter Michelson, a Stanford University physics professor affiliated with the Department of Energy.

Another, far more speculative theory suggests that perhaps time lags result not from anything in the environment around the black hole, but from the gamma rays’ long journey from the black hole to our telescopes. If the theorized idea of quantum gravity is correct, then at its smallest scale space is not a smooth medium but a tumultuous, boiling froth of “quantum foam.” Lower-energy (and thus lighter) gamma rays would travel faster through this foam than higher-energy (and thus heavier) gamma rays. Over the course of 12.2 billion light years, this very small effect could add up to a significant delay.

The Fermi results provide the strongest test to date of the speed of light’s consistency at these extreme energies. As Fermi observes more gamma-ray bursts, researchers can look for time lags that vary with respect to the bursts. If the quantum gravity effect is present, time lags should vary in relation to the distance. If the environment around the burst origin is the cause, the lag should stay relatively constant no matter how far away the burst occurred.

“This one burst raises all sorts of questions,” Michelson says. “In a few years, we’ll have a fairly good sample of bursts, and may have some answers.”

Source: Eurekalert

February 19, 2009December 24, 2015 by Fraser Cain

Is the Earth Round?

The Earth isn’t flat, that’s for sure. And if you look at a photograph, the Earth really looks round. But how round is it?

The actual shape of the Earth is actually an oblate spheroid – a sphere with a bulge around the equator. The Earth is bulged at its equator because it’s rapidly rotating on its axis. The centripetal force of the rotation causes the regions at the equator to bulge outward. And it actually makes a pretty big difference. The diameter of the Earth, measured across the equator is 43 km more than when you measure the diameter of the Earth from pole to pole.

This bulge has some interesting implications. For example, it means that the point on Earth furthest from the center isn’t actually Mount Everest, but Mount Chimborazo in Ecuador. Only because Chimborazo is closer to the Earth’s equator.

So how smooth is the Earth. When billiard balls are manufactured, they aim for a tolerance of 0.22%. The Earth has a tolerance of 0.17%, so it’s actually smoother than a billiard ball. If you could hold the Earth in your hands, it would feel smoother than a billiard ball.

But the Earth definitely isn’t flat.

We have written many articles about the Earth for Universe Today. Here’s a cool article about looking at the Earth as if it’s an extrasolar planet.

Want more resources on the Earth? Here’s a link to NASA’s Human Spaceflight page, and here’s NASA’s Visible Earth.

We have also recorded an episode of Astronomy Cast about Earth, as part of our tour through the Solar System – Episode 51: Earth.

February 19, 2009December 24, 2015 by Fraser Cain

What is the Tallest Volcano on Earth?

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The tallest volcano on Earth is Mauna Kea, one of the 5 volcanos that make up the Big Island of Hawaii. The summit of Mauna Kea is 4,205 meters above sea level, but its true height is much larger. When measured from the sea floor, Mauna kea is more than 9,000 meters tall, making it the tallest mountain on Earth.

Mauna Kea is part of the network of volcanos above the Hawaiian hotspot. The tectonic plate that has the Hawaiian islands is slowly moving above the hotspot, and it recently carried Mauna Kea away from the hotspot. Scientists believe that Mauna Kea is now dormant; it last erupted about 4,500 years ago. Although, researchers do think it’s going to erupt again, the time between eruptions is measured in hundreds of years. The most active volcano on the island, Kilauea, erupts every few years.

Even though the Hawaiian islands are warm and tropical, Mauna Kea is so tall that it has regular snowfalls in the winter months. Geologists have even found deposits created by glaciers during recent ice ages. There were probably three glacial episodes in the last 200,000 years. People regularly ski on the slopes of Mauna Kea.

Although Mauna Kea is the tallest volcano, it’s only about 40 meters taller than the nearby Mauna Loa, which is the biggest volcano on Earth. Mauna Loa has more than 75,000 cubic kilometers of material.

And the biggest volcano in the Solar System isn’t on Earth, but on Mars. The enormous Olympus Mons is 27 km tall, and contains 100 times more material than Mauna Loa.

We have written many articles about the Earth for Universe Today. Here’s an article about the biggest volcano on Earth, and here’s an article about the biggest volcano in the Solar System.

Want more resources on the Earth? Here’s a link to NASA’s Human Spaceflight page, and here’s NASA’s Visible Earth.

We have also recorded an episode of Astronomy Cast about Earth, as part of our tour through the Solar System – Episode 51: Earth.