Universe Today

June 1, 2009December 24, 2015 by Nancy Atkinson

Spaceships on the Move!

Atlantis hitches a ride on a 747 back to KSC. Credit: NASA TV

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Atlantis has begun her journey back home to the Kennedy Space Center, hitching a ride on the Shuttle Carrier Aircraft, a modified Boeing 747. The flight took off at about 11:05 EDT on Monday morning from Edwards Air Force Base, and the duo will fly to Biggs Army Air Field in El Paso, Texas and spend the night there before resuming the cross-country trip on Tuesday. Of course, Atlantis just returned from space, landing at Edwards on May 24, concluding the STS-125 mission to service the Hubble Space Telescope for the last time. Track the flight here.

But Atlantis isn’t the only spacecraft on the move. The shuttle Endeavour just rolled around to launchpad 39A, after standing down from its potential rescue mission, (STS-400) in case Atlantis was unable to return home, and now is preparing for the STS-127, which will hopefully launch around June 13. Watch the video of the rollaround below. And the next missions to the Moon are now poised for launch.

On May 28, the Lunar Reconnaissaince Orbiter and the Lunar Crater Observation and Sensing Satellitespacecraft were transported to the launch pad. The transport of the stacked and encapsulated LRO/LCROSS payload began at about 2 am local time and culminated with the attachment of the payload atop the Atlas AV-20 rocket at about 9:30am.

The spacecraft will launch together June 17 from Cape Canaveral Air Force Station in Florida.

Using a suite of seven instruments, LRO will help identify safe landing sites for future human explorers, locate potential resources, characterize the radiation environment and test new technology. LCROSS will seek a definitive answer about the presence of water ice at the lunar poles. LCROSS will use the spent second stage Atlas Centaur rocket in an unprecedented way that will culminate with two spectacular impacts on the moon’s surface.

Learn more about LRO, and keep track of the countdown here.

May 31, 2009December 29, 2015 by Nancy Atkinson

Carnival of Space #105

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This week’s Carnival of Space is hosted by Ian O’Neill over at Discovery Space. Yes, Ian is at the Space Disco — if you’re confused, read this.

Click here to read the Carnival of Space #105

And if you’re interested in looking back, here’s an archive to all the past carnivals of space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, let Fraser know if you can be a host, and he’ll schedule you into the calendar.

Finally, if you run a space-related blog, please post a link to the Carnival of Space. Help us get the word out.

May 29, 2009December 24, 2015 by Brian Ventrudo

Astronomers Observe Formation of Largest Bound Structures in the Universe

The massive radio galaxy PKS 0745-191, for which the cluster is named, appears at the center of this Hubble Space Telescope image. The picture forms the inset in the Suzaku image above.

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An international team of astronomers has mapped the density and temperature of X-ray-emitting gas in the outskirts of a distant galaxy cluster. The results, obtained with the orbiting Japanese X-ray telescope Suzaku, give the first complete X-ray view of a galaxy cluster, and provide insight into how such clusters come together.

“These Suzaku observations are exciting because we can finally see how these structures, the largest bound objects in the universe, grow even more massive,” said Matt George, the study’s lead author at the University of California, Berkeley.

The team trained Suzaku’s X-ray telescopes on the massive galaxy cluster PKS 0745-191, which lies 1.3 billion light-years away in the southern constellation Puppis. Between May 11 and 14, 2007, Suzaku acquired five images of the million-degree gas that permeates the cluster.

The X-ray images of the cluster helped astronomers measure the temperature and density of the gas. These provide clues about the gas pressure and cluster’s total mass. The hottest, densest gas lies near the cluster’s center, while gas temperature and density steadily decline away from the center.

Astronomers believe the gas in the inner part of a galaxy cluster has settled into an ordered “relaxed” state in equilibrium with the cluster’s gravity. But in the outer regions, where galaxies first begin a billion-year plunge towards the cluster’s center, the gas remains in a disordered state because it’s still falling inward.

“Clusters are the most massive, relaxed objects in the universe, and they are continuing to form now,” said team member Andy Fabian at the Cambridge Institute of Astronomy in the UK.

For the first time, this study shows X-ray emission and gas density and temperature out to the region where the gas is disordered, and where the cluster continues to assemble.

“It gives us the first complete X-ray view of a cluster of galaxies”, said Fabian.

This Suzaku image shows X-ray emission from hot gas throughout the galaxy cluster PKS 0745-191. Brighter colors indicate greater X-ray emission. The circle is 11.2 million light-years across and marks the region where cold gas is now entering the cluster. Inset: A Hubble optical image of the cluster's central galaxies is shown at the correct scale.

In PKS 0745-191, the gas temperature peaks at 164 million degrees Fahrenheit (91 million C) about 1.1 million light-years from the cluster’s center. The temperature declines smoothly with distance, dropping to 45 million F (25 million C) more than 5.6 million light-years from the center.

To accurately measure X-ray emission at the cluster’s edge requires detectors with exceptionally low background noise. Suzaku has advanced X-ray detectors, and it lies in a low-altitude orbit near the Earth’s magnetic field, which protects the observatory from energetic particles from the sun and beyond.

“With more Suzaku observations in the outskirts of other galaxy clusters, we’ll get a better picture of how these massive structures evolve,” added George.

Suzaku (Japanese for “red bird of the south”) was launched on July 10, 2005. The observatory was developed at the Japanese Institute of Space and Astronautical Science (ISAS), which is part of the Japan Aerospace Exploration Agency (JAXA), in collaboration with NASA and other Japanese and U.S. institutions.

The results were published in the May 11 edition of the Monthly Notices of the Royal Astronomical Society.

Source: NASA

May 29, 2009December 24, 2015 by Nancy Atkinson

Dear JPL: I Have an Idea on How to Rescue the Spirit Rover

Drawing submitted to JPL by 7-year old Julian. Used by permission.

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We’re all concerned about the Spirit rover, currently stuck in some soft soil on Mars. But some people are actually working hard to figure out how to rescue the rover. That includes a 7-year old boy named Julian who sent this drawing in to JPL with his idea of how help Spirit: use the robotic arm as a “tripod” to lift the rover up and help move it out of the spot where it is embedded. Julian, you have a bright future ahead of you as an engineer! “We are getting a lot of interesting suggestions from the public,” said JPL’s John Callas, MER project manager, “and we think that’s wonderful. It shows people are interested in these rovers. We certainly are canvassing the full range of possibilities to get Spirit unstuck.”

And Callas said they are actually planning to use the robotic arm to help get Spirit unstuck, but not quite the way Julian had in mind.

“We’re doing a parallel approach,” Callas told Universe Today, “doing things both on Earth and on Mars. Spirit is using her instruments to assess the terrain and the nature of the materials where she is stuck. Just last night we made the decision to use the robotic arm to look underneath the belly of the rover to see if we can determine how the vehicle is embedded and if it may be high centered on some small rocks under the rover. We’ll also look at the wheels to see how the middle wheels are dug in.”

Callas said this is a technique the robotic arm was never designed to do. “So, we tested it first on Opportunity and it worked quite well, so that’s the plan for what we’ll do with Spirit this weekend.”

Spirit has also been busy taking remote sensing images of the surrounding terrain with all its instruments to try to characterize the soils and their properties. Callas said “soils” because there actually appears to be two different types of materials where the rover is stuck, with a different type of soil on the left side of the rover from the right.

Workers at JPL start digging to replicate Spirit's situation on Mars. Image credit: NASA/JPL

The rover team will use the data to create a soil simulant to be used in the JPL test bed, basically a large sandbox where an engineering model of the rover identical to Spirit and Opportunity can be used to simulate Spirit’s predicament. There, the team can experiment with how best to get the rover out.

However, the test has been held up because of problems with work station that controls the test facility, but Callas said they are hoping by later today (Friday) to get started with the simulations.

They’ll start by putting the simulated Mars regolith, which is called baghouse dust, (ground basaltic material, Callas said) and use enough to test just one wheel of the rover. “If it exhibits the same characteristics we’re seeing on Mars, then we’ll truck in tons of that material to do the tests with the rover,” said Callas. If not, they’ll have to go back to the drawing board.

Spirit's wheels embedded in the Martian regolith. Credit: NASA/JPL

Spirit has long been without the use of her right front wheel, which doesn’t help the situation, and recently the left middle wheel was jammed, but now appears to be working again. The one piece of good news is that Mars itself provided a little help by sending a gust of wind Spirit’s way, cleaning off the solar panels, making more energy available to the rover. Spirit now has over 80% of its potential power, with 843 watt hours available, as opposed to earlier where the rover was operating at less than 200 watt hours.

Callas said he is optimistic about getting Spirit unstuck. “We saw that even on the last drive that the rover was still moving, even though it was only fractionally, based on the wheel spin. So, that tells us material is still being transported underneath the wheels. Given enough time and enough wheel spinning we should be able to get out. If that changes, if we get a situation where we have a hundred per cent slip, then we’re in trouble. But we’re not at that point yet, — even if we’re at 99.9%, that makes a big difference between 100%.”

And if this latest attempt doesn’t work, Callas says they have some other ideas up their robotic arm sleeves. “There are some exotic things we would consider if the more traditional methods don’t work,” he said. We have a lot of arrows in our quiver, or tools in our toolbelt to try first. ”

And they always have Julian to rely on, too.

Source: Interview with John Callas
Julian’s picture on Twitpic — check out the comments!

May 29, 2009December 24, 2015 by Nancy Atkinson

ISS Crew Expands; Now’s the Time To Expand Your Knowledge of the Orbiting Outpost

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The crew of the International Space Station has now increased to six for the first time with the arrival of three new residents. Also, for the first time all the ISS partners are represented on board the station at once as astronauts from NASA, CSA, ESA, JAXA and Russia are all part of the crew. The Soyuz TMA-15 docked with the ISS at 12:34 UT, and the new crewmembers entered the station at 14:14 UT. “I sincerely appreciate the international partners’ continuous efforts to enable the 6-person crew on-board after having overcome so many challenge,” said Dr. Keiji Tachikawa, president of JAXA. I believe that an increased number of ISS crewmembers will make use of the ISS … capabilities to the utmost extent …and this contributes to the safe and steady operation of the ISS.”

Now that the science and all sorts of other activity will be ramping up on the space station, it’s a good time to get to know your ISS a little better. Here’s a few links that will help:

Very cool interactive ISS site, with talking astronauts! Take a 360 degree tour of the station and find out what it is like to live on board.

An interactive feature about the International cooperation.

Find out more about the science on board the ISS.

This very cool feature allows you to see images of Earth — as seen from space — from the current location of the space station. Note: not live pictures, but images taken earlier and when you visit the website, the telemetry is calculated to give you a picture from the station’s approximate location.

Find out when you can see the station flying over your backyard:
Heaven’s Above
NASA’s Real Data site
ESA’s “ISS – Where is it Now” site

Follow the latest ISS news from NASA.

ESA’s ISS site.

Canada’s ISS site.

If you are into video games: Space Station Sim

May 29, 2009December 24, 2015 by Tammy Plotner

Weekend SkyWatcher’s Forecast – May 29-31, 2009

Greetings, fellow SkyWatchers! Have you been watching the lovely crescent Moon as it climbs higher each night? What a beauty! With warmer nights in the northern hemisphere and cooler evenings bringing clear, deep views to the south – why not spend some time stargazing? We’ve got some great lunar features lined up for you to help you along with your lunar club challenges – as well as a bright galaxy and an interesting variable star. Time to dust off your optics and head out into the night…

Friday, May 29, 2009 – Today we begin with the 1794 birth on this date of Johann Heinrich von Madler who, along with Wilhelm Beer, published the most complete map up to that time of the Moon, Mappa Selenographia. How fitting, then, that we should visit the Moon tonight! We’re going in search of another Lunar Club Challenge that will prove difficult because you’ll be working without a map.

Relax! This will be much easier than you think. Starting at Mare Crisium, move along the terminator to the north following the chain of craters until you identify a featureless oval that looks similar to Plato seen on a curve. This is Endymion, and if you can’t spot it tonight don’t worry. We’ll look in the days ahead at some features that will point you to it!

Since tonight will be our last chance to galaxy hunt for a while, let’s take a look at one of the brightest members of the Virgo Cluster – M49 (RA 12 29 46 Dec +07 59 59). Located about 8 degrees northwest of Delta Virginis, and almost directly between a pair of 6th magnitude stars, the giant elliptical M49 holds the distinction of being the first galaxy in the Virgo Cluster to be discovered – and just the second beyond our local group.

At magnitude 8.5, this type E4 galaxy will appear as an evenly illuminated egg shape in almost all scopes, and as a faint patch in binoculars. Although a possible supernova event occurred in 1969, don’t confuse the foreground star noted by Herschel with something new! Most telescopes won’t be able to pick this region apart – especially with the Moon so near – but there are also many fainter companions near M49, including NGC 4470. A sharp-eyed observer named Halton Arp noticed them and listed them as ‘‘Peculiar Galaxy 134 ’’ – one with ‘‘fragments’’!

Saturday, May 30, 2009 – Today we begin with the 1423 birth of Georg von Peuerbachon this date, a follower of Ptolemy’s astronomy. Georg calculated eclipses; observed Halley’s Comet before it was so named; and created astronomical instruments. Following Georg nearly half a millennium later was Hannes Alfven, born in 1908. Alfven’s life work was plasma and its electric and magnetic forces. Lastly, we have Aleksei Arkhipovich Leonov, who was born in 1934. Leonov was the first man to climb out of a spacecraft (the Voskhod II ) and into space. He was the first true ‘‘astrophotographer’’ as he filmed for 10 minutes while orbiting!

Tonight let’s take our own journey to the Moon and look at a beautiful series of craters – Fabricius, Metius, and Rheita.

Bordered on the south by shallow Jannsen, Lunar Club Challenge Fabricius is a 78-kilometer diameter crater highlighted by two small interior mountain ranges. To its northeast is Metius, which is slightly larger, with a diameter of 88 kilometers. Look carefully at the two. Metius has much steeper walls, while Fabricius shows differing levels and heights. Metius’s smooth floor also contains a very prominent B crater on the inside of its southeast crater wall. Further northeast is the lovely Rheita Valley, which stretches almost 500 kilometers and appears more like a series of confluent craters than a fault line. The 70-kilometer diameter crater Rheita is far younger than this formation
because it intrudes upon it. Look for a bright point inside the crater, its central peak.

While the Moon is still west, let’s have a look at telescopic star W Virginis located about 3.5 degrees southwest of Zeta (RA 13 26 02 Dec -03 22 43). This 11,000 light-year-distant Cepheid-type variable is, oddly enough, a Population II lying outside the galactic plane. This expanding and contracting star goes through its changes in a little over 17 days and will vary between 8th and 9th magnitude. Although it is undeniably a Cepheid, it breaks the rules by being both out of place in the cosmic scheme and displaying abnormal spectral qualities!

Sunday, May 31, 2009 – Today we begin with noting the 1872 birth on this date of Charles Greeley Abbot, who may very well have been the first astronomer to suspect that the radiation from the Sun might vary over time, and thus it was technically a variable star. When Abbot became the director of the Smithsonian Astrophysical Observatory (SAO), the SAO established a network of solar radiation observatories around the world. After many decades of study, a connection was made between solar variations and weather on Earth.

Tonight the Moon will be our companion. Now well risen above atmospheric disturbance, this would be a great time to have a look for several Lunar Club Challenges you might have missed. Most prominent of all will be two craters to the north named Atlas and Hercules. The easternmost Atlas was named for the mythical figure who bore the weight of the world on his shoulders. The crater spans 87 kilometers and contains a vivid Y-shaped rima in the interior basin. Western Hercules is considerably smaller at 69 kilometers in diameter and shows a deep interior crater, called G. Power up, and look for the tiny E crater, which marks the southern crater rim. North of both is another unusual feature that many observers miss. It is a much more eroded and far older crater showing only a basic outline; this crater is known as Atlas E.

Since we’re here, let’s take a crater walk and see how many features we can identify. . . Good luck and clear skies!

Atlas region: (1) Mare Humboldtianum, (2) Endymion, (3) Atlas, (4) Hercules, (5) Chevalier, (6) Shuckburgh, (7) Hooke, (8) Cepheus, (9) Franklin, (10) Berzelius, (11) Maury, (12) Lacus Somniorum, (13) Daniel, (14) Grove, (15) Williams, (16) Mason, (17) Plana, (18) Burg, (19) Lacus Mortis, (20) Baily, (21) Atlas E, (22) Keldysh, (23) Mare Frigoris, (24) Democritus, (25) Gartner, (26) Schwabe, (27) Thales, (28) Strabo, (29) de la Rue, and (30) Hayn.

Until next week? Ask for the Moon, but keep on reaching for the stars!

This week’s awesome images are Johann Heinrich von Madler (historical image), M49 (credit—Palomar Observatory, courtesy of Caltech), Aleksey Arkhipovich Leonov (archival image), Fabricius, Metius, and Rheita (credit—Alan Chu), Charles Greeley Abbot (historical image) and Atlas region (credit—Greg Konkel, annotations by Tammy Plotner). We thank you!

May 29, 2009December 24, 2015 by Nancy Atkinson

Could Ghost-Like Object Found by Chandra Be Another ‘Voorwerp’?

The ghost of HDF 130. Credit: X-ray (NASA/CXC/IoA/A.Fabian et al.); Optical (SDSS), Radio (STFC/JBO/MERLIN)

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The Chandra X-ray Observatory has found a cosmic “ghost” lurking around a distant supermassive black hole. Astronomers think this high-energy apparition is evidence of a huge eruption produced by the black hole. But this blue blob looks eerily similar to another cosmic blob of gas found by Galaxy Zoo member Hanny Van Arkel, the famous object called Hanny’s Voorwerp. Could the two objects be similar?

Astronomers say the “ghost” found by Chandra is the remains of a diffuse X-ray source, lingering after other radiation from the black hole’s outburst died away. The object, HDF 130 is over 10 billion light years away and existed at a time 3 billion years after the Big Bang, when galaxies and black holes were forming at a high rate.

Hanny’s Voorwerp has been a mystery ever since it was found in 2007 as part of the Galaxy Zoo project. Recent research on the object reveals that the Voorwerp is also likely to be a remnant from a black hole outburst. In the original Sloan Digital Sky Survey images of Hanny’s Voorwerp, the object showed up as blue, however further spectral analysis showed it is actually green. The Voorwerp was studied by the Swift gamma-ray satellite, which also can pick up ultraviolet and X-ray emissions, but the satellite didn’t come up with anything conclusive. However, the Westerbork Synthesis Radio Telescope (WSRT) took a look at Hanny’s Voorwerp and determined that indeed, black hole jets were allowing beams of intense optical and ultraviolet emissions from the black hole to heat and illuminate a small part of a large gas cloud that partially surrounds the nearby galaxy, IC 2497.

But Galaxy Zoo astronomers suspect X-rays might play a role in the Voorwerp, too. It was recently imaged by the Suzaku X-ray telescopes to see if is visible in that part of the spectrum, as well as to probe the current activity of the supermassive black hole. The results of that observation are still being analyzed. Yale astronomer Kevin Schawinski recently wrote in the Galaxy Zoo Blog that detecting hard X-ray photons would provide evidence of an active supermassive black hole in IC 2497, which would be illuminating the Voorwerp. “If on the other hand we don’t pick up anything, then we can be sure that the black hole has stopped feeding, i.e. it has genuinely shut down,” Schawinski wrote.

So are the two objects, the “ghost” of HDF 130 and Hanny’s Voorwerp similar? Yes – and no – said Chandra scientist Dr. Peter Edmonds.

“There are indeed some basic similarities between these two objects, in that both were generated by eruptions from a supermassive black hole, either in the form of bright radiation or jets, Edmonds told Universe Today.”Also, in both cases the eruption from the black hole seems to have died down.”

The details of the two objects, however, are very different, Edmonds said. “Hanny’s Voorwerp involves a light echo while the X-ray ghost was thought to form by an interaction between the comic background radiation and particles in a jet. They’re obviously seen at very different wavelengths. Also, the ghost is found in the early Universe at much greater distances than Hanny’s Voorwerp and is physically much larger.”

Additionally, the Chandra team suspects a very powerful and large eruption was responsible for the formation of the ghost, much more powerful than the one for Hanny’s Voorwerp.

Andy Fabian of the Cambridge University in the United Kingdom, lead author on the paper on the ghost of HDF 130, thinks the object’s X-ray glow is evidence of an outburst equivalent to about a billion supernovas, which blasted particles at almost the speed of light. When the eruption was ongoing, it produced prodigious amounts of radio and X-radiation, but after several million years, the radio signal faded from view as the electrons radiated away their energy.

This is the first X-ray ghost ever seen after the demise of radio-bright jets. Astronomers have observed extensive X-ray emission with a similar origin, but only from galaxies with radio emission on large scales, signifying continued eruptions. In HDF 130, only a point source is detected in radio images, coinciding with the massive elliptical galaxy seen in its optical image.

This radio source indicates that HDF 130’s supermassive black hole may be growing.

With Hanny’s Voorwerp, however, astronomers are still searching for any sign of activity from the black hole.

Another argument that the two objects are different is their shape. The linear shape of the HDF 130’s X-ray source is consistent with the shape of radio jets and not with that of a galaxy cluster, which is expected to be circular. The energy distribution of the X-rays is also consistent with the interpretation of an X-ray ghost.

WSRT observations of Hanny's Voorwerp. Credit: ASTRON

Hanny’s Voorwerp has all the hallmarks of an interacting system. “The gas probably arises from a tidal interaction between IC 2497 and another galaxy, which occurred several hundred million years ago,” said Dr. Tom Oosterloo, part of the team that studied the Voorwerp with WSRT.

There are more differences between the two objects, primarily that ghosts like the one from HDF 130 may be prevalent in the universe, while the Voorwerp might just be a one-time occurance. “The stream of gas ends three hundred thousand light years westwards of IC2497, and all the evidence points towards a group of galaxies at the tip of the stream being responsible for this freak cosmic accident,” said Oosterloo.

Chandra astronomer Caitlin Casey, also of Cambridge said, “This result hints that the X-ray sky should be littered with such ghosts, especially if black hole eruptions are as common as we think they are in the early Universe.”

So now that astronomers know where and now to look for X-ray objects like the one by HDF 130, we’re likely to hear about more cosmic X-ray ghosts in the future. But Hanny’s Voorwerp appears to be unique.

Sources: Chandra, previous UT article, email exchange with Dr. Peter Edmonds, Galaxy Zoo

May 28, 2009December 24, 2015 by Nancy Atkinson

Researchers Seeing Red on Ocean Health

The MODIS instrument on NASA’s Aqua satellite compiled this global view of the amount of fluorescent light emitted by phytoplankton in the ocean. Credit: Oregon State University

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With the help of an orbiting satellite, researchers have conducted the first global analysis of the health and productivity of ocean plants. Using the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite, scientists have for the first time measured remotely the amount of fluorescent red light emitted by ocean phytoplankton and assess how efficiently the microscopic plants are turning sunlight and nutrients into food through photosynthesis. Now that they have their first data, this method should allow scientists to effectively keep an eye on the health of our oceans. So what did they find out so far?

Over the past two decades, scientists have employed various satellite sensors to measure the amount and distribution of the green pigment chlorophyll, an indicator of the amount of plant life in the ocean. But with MODIS, “red-light fluorescence” has been observed over the open ocean.

“Chlorophyll gives us a picture of how much phytoplankton is present,” said Scott Doney, a marine chemist from the Woods Hole Oceanographic Institution and a co-author of the paper. “Fluorescence provides insight into how well they are functioning in the ecosystem.”

Phytoplankton -- such as this colony of chaetoceros socialis -- naturally give off fluorescent light as they dissipate excess solar energy that they cannot consume through photosynthesis. Credit: Maria Vernet, Scripps Institution of Oceanography

Red-light fluorescence reveals insights about the physiology of marine plants and the efficiency of photosynthesis, as different parts of the plant’s energy-harnessing machinery are activated based on the amount of light and nutrients available. For instance, the amount of fluorescence increases when phytoplankton are under stress from a lack of iron, a critical nutrient in seawater. When the water is iron-poor, phytoplankton emit more solar energy as fluorescence than when iron is sufficient.

The fluorescence data from MODIS gives scientists a tool that enables research to reveal where waters are iron-enriched or iron-limited, and to observe how changes in iron influence plankton. The iron needed for plant growth reaches the sea surface on winds blowing dust from deserts and other arid areas, and from upwelling currents near river plumes and islands.

The new analysis of MODIS data has allowed the research team to detect new regions of the ocean affected by iron deposition and depletion. The Indian Ocean was a particular surprise, as large portions of the ocean were seen to “light up” seasonally with changes in monsoon winds. In the summer, fall, and winter – particularly summer – significant southwesterly winds stir up ocean currents and bring more nutrients up from the depths for the phytoplankton. At the same time, the amount of iron-rich dust delivered by winds is reduced.

This data-based map shows iron dust deposition on the oceans in spring 2004. Areas with low dust deposition have high fluorescence yields. Credit: NASA's Scientific Visualization Studio

“On time-scales of weeks to months, we can use this data to track plankton responses to iron inputs from dust storms and the transport of iron-rich water from islands and continents,” said Doney. “Over years to decades, we can also detect long-term trends in climate change and other human perturbations to the ocean.”

Climate change could mean stronger winds pick up more dust and blow it to sea, or less intense winds leaving waters dust-free. Some regions will become drier and others wetter, changing the regions where dusty soils accumulate and get swept up into the air. Phytoplankton will reflect and react to these global changes.

Single-celled phytoplankton fuel nearly all ocean ecosystems, serving as the most basic food source for marine animals from zooplankton to fish to shellfish. In fact, phytoplankton account for half of all photosynthetic activity on Earth. The health of these marine plants affects commercial fisheries, the amount of carbon dioxide the ocean can absorb, and how the ocean responds to climate change.

“This is the first direct measurement of the health of the phytoplankton in the ocean,” said Michael Behrenfeld, a biologist who specializes in marine plants at the Oregon State University in Corvallis, Ore. “We have an important new tool for observing changes in phytoplankton every week, all over the planet.”

Source: NASA

May 28, 2009December 24, 2015 by Nancy Atkinson

Astrometry Finally Finds an Exoplanet

This artist's concept shows the smallest star known to host a planet. Image credit: NASA/JPL-Caltech

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Using the method of astrometry to find planets orbiting other stars has been around for 50 years, and until now it hasn’t bagged a single exoplanet. But finally, astronomers found a Jupiter-sized planet , called VB 10b, using this method. Astrometry is difficult and requires very precise measurements over long periods of time. So why did they keep trying for so long? “This method is optimal for finding solar-system configurations like ours that might harbor other Earths,” said astronomer Steven Pravdo of JPL. “We found a Jupiter-like planet at around the same relative place as our Jupiter, only around a much smaller star. It’s possible this star also has inner rocky planets. And since more than seven out of 10 stars are small like this one, this could mean planets are more common than we thought.”

The finding confirms that astrometry could be a powerful planet-hunting technique for both ground- and space-based telescopes. For example, a similar technique would be used by SIM Lite, a NASA concept for a space-based mission that is currently being explored.

The newfound exoplanet is about 20 light-years away in the constellation Aquila. It is a gas giant, with a mass six times that of Jupiter’s, and an orbit far enough away from its star to be labeled a “cold Jupiter” similar to our own. In reality, the planet’s own internal heat would give it an Earth-like temperature.

The planet’s star, called VB 10, is tiny. It is what’s known as an M-dwarf and is only one-twelfth the mass of our sun, just barely big enough to fuse atoms at its core and shine with starlight. For years, VB 10 was the smallest star known — now it has a new title: the smallest star known to host a planet. In fact, though the star is more massive than the newfound planet, the two bodies would have a similar girth.

Because the star is so small, its planetary system would be a miniature, scaled-down version of our own. For example, VB 10b, though considered a cold Jupiter, is located about as far from its star as Mercury is from the sun. Any rocky Earth-size planets that might happen to be in the neighborhood would lie even closer in.

“Some other exoplanets around larger M-dwarf stars are also similar to our Jupiter, making the stars fertile ground for future Earth searches,” said Stuart Shaklan, Pravdo’s co-author and the SIM Lite instrument scientist at JPL. “Astrometry is best suited to find cold Jupiters around all kinds of stars, and thus to find more planetary systems arranged like our home.”

Two to six times a year, for the past 12 years, Pravdo and Shaklan have bolted their Stellar Planet Survey instrument onto Palomar’s five-meter Hale telescope to search for planets. The instrument, which has a 16-megapixel charge-coupled device, or CCD, can detect very minute changes in the positions of stars. The VB 10b planet, for instance, causes its star to wobble a small fraction of a degree. Detecting this wobble is equivalent to measuring the width of a human hair from about three kilometers away.

Other ground-based planet-hunting techniques in wide use include radial velocity and the transit method. Like astrometry, radial velocity detects the wobble of a star, but it measures Doppler shifts in the star’s light caused by motion toward and away from us. The transit method looks for dips in a star’s brightness as orbiting planets pass by and block the light. NASA’s space-based Kepler mission, which began searching for planets on May 12, will use the transit method to look for Earth-like worlds around stars similar to the sun.

“This is an exciting discovery because it shows that planets can be found around extremely light-weight stars,” said Wesley Traub, the chief scientist for NASA’s Exoplanet Exploration Program at JPL. “This is a hint that nature likes to form planets, even around stars very different from the sun.”

Source: JPL

May 28, 2009December 24, 2015 by Nancy Atkinson

We All Need to Chill Out About Flight Tests

Artist concept of the Ares 1-X launch. Credit: NASA

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At a session today from the International Space Development Conference going in Orlando, Florida, the CEO of the commercial space company XCOR Aerospace had a few suggestions for all the eager space enthusiasts out there concerning test flights. In so many words Jeff Greason said everyone needs to chill out about the results from initial test flights. Of course, he was talking about all the test flights taking place with commercial space endeavors, but with the Ares 1-X getting ready to head to the launch pad for its first flight test, scheduled for August, perhaps we all need heed Greason’s advice and let the experts do their jobs.

Greason said in the past when they first started testing their early designs, “no one knew where Mojave was, we could test all sorts of strange things, and people would not be Twittering and blogging about what we did every day. But now it’s going on under a glare of publicity.”

While he appreciates the interest everyone is showing in the nascent commercial spaceflight industry and how people are watching with great enthusiasm and consuming every scrap of news, he is not exactly thrilled with tone of some of the commentary on what is being said on commercial flight tests.

“It’s called flight test for a reason,” Greason said. “You find problems, you always do. Any airplane you’ve ever ridden on had problems turn up on flight test program. Some of the most successful aircraft programs in history had a ridiculous number of problems show up in the flight test program. There is no correlation whatsoever between whether you or not you have problem in the flight test program and how good the finished product is. But there is a huge correlation whether you fix the problems you find in flight tests. ”

Greason said it isn’t helpful for journalists and the public to jump on every glitch and issue that comes up in every mission and say the sky is falling. “Just wait until flight tests to finish and by then there should be an answer. I see lot of blog posts three minutes after a flight test, saying the sky is falling. Stuff happens. So, I have a plea for the knowledgeable people out there: When you’re neighbor says ‘The sky is falling,’ tell them, ‘No, it’s just flight tests.”

Greason said flight tests are designed to find the problems and allow the engineers to fix the problems. But they take time. “That’s why I or anyone else never commits to how long flight tests lasts. Flight tests take as long as it going to take. When you fix the problems, that’s the end of the flight test program.”

Greason said he knows everyone is enthused because they want to see the missions happen, but every vehicle is a “new beast with their own design issues.”

More information on how XCOR designs and tests their vehicles, see this article from TimeCompression.com.

More information about the upcoming tests of the Arex 1-X.