Astrocast.TV

This week is World Water Week. The big event takes place in Stockholm Sweden where Stockholm International Water Institute SIWI is organizing this, since 1991, yearly event. This year the topic, besides the fact that it is all about water of course, is The Water Quality Challenge: Prevention, Wise Use and Abatement.

Access to clean water and proper sanitation is one of the 8 millenium goals. Better understanding of the water cycle is thus an important task for our global society, particularly in the developing countries. With increased urbanizations in areas where access to fresh water seems to be in peril makes events like World Water Week and research connected to better understanding of the water cycle an even high political and scientific priority. The overall niche for the current World Water Week period 2009-2012 is Water – Responding To Global Change.

Observing inland water from space
Earth observations from space have been used as a source of information about water for many years. We’ve seen satellite images of various floods on numerous occasions. The immense flood in Pakistan is particularly impressive in the many satellite images from both ESA and NASA satellites.

New space-based observation techniques are emerging though. ESA’s Soil Moisture and Ocean Salinity – SMOS has the potential of becoming an additional space-based technique to underpin our understanding – and warning of potentially hazards floods – by giving information about the degree of water saturation of the soil in the vicinity of rivers like Indus. If the soil is saturated with moisture at the point when rivers are flooding the uptake of water by surrounding soil will be limited.

SMOS and Pakistan flood:

In May I talked to one of the pioneers in the field of satellite altimetry and SMOS expert on retrieving information about soil moisture – professor Philippa Berry. You can watch and learn here:

or directly here:
The problem in Pakistan and right now is too much water, but the areas downstream from the Himalayas have also the opposite problem, namely too little water. This particular complex problem is discussed in a feasibility study ordered by The Norwegian Ministry of Foreign Affairs. It is a challenge for the people in the Hindu Kush-Himalayas to adapt to the increased climatic risk of severe floods and droughts.  Read the report  Too much – Too little Water: Adaptation to Climate Change in the Hindu Kush Himalayas and Central Asia.

With the help of another kind of satellite, GRACE, measuring variations in gravity, one is able to see that ground water is retracting from large areas in India. This vanishing of groundwater is mainly due to human activities like irrigation of cropland. Water management is clearly done better with the help of space based observations.

This month we are reprising a popular segment of The Astronomer’s Universe that talks about the giant star Eta Carinae. This stellar behemoth is a supermassive star that will go supernova soon.

Astronomers have been studying the region of the sky in the Southern Hemisphere constellation Carina with great interest since the 1840s. That’s Eta Carinae — a supermassive star embedded in a nebula there brightened up considerably, making it one of the brightest stars in the sky. Over time, it dimmed down again. Today, we know that Eta Carinae is a massive stellar giant, called a luminous blue variable, is paired with a white dwarf. We also know that Eta Carinae is going to explode as a type of supernova called a hypernova. It will be an incredibly bright event, something that could brighten that region of the sky again when it finally occurs.

Eta Carinae is part of the vast Carina Nebula, a cloud of gas and dust and bright stars that lies about 7,500 light-years from Earth. The star itself has about 100 times the mass of the Sun, making it one of the most massive stars known. If this star could be placed in our solar system where the Sun is now, its atmosphere would reach all the way out past the orbit of Jupiter.

Eta Carinae is a million times brighter than the Sun, and it may only be a few million years old. That makes it a newborn in comparison to stars like the Sun, which is around 6 billion years old. Stars as massive as Eta Carinae live fast and die young.  This one has entered its final stage of life and is very unstable. It’s losing mass through giant outbursts, and the material it’s puffing off is creating a double-lobed cloud around the star. Astronomers are zeroing in on that cloud to understand the process that is causing the star to emit such prodigious quantities of material. Is this a part of the death of all supermassive stars?  When will this star ultimately explode?  Those are questions astronomers are still working to answer through continuing observations of Eta Carinae.

Astronomers at the University of Colorado used the Hubble Space Telescope to measure the speed and make-up of gases being ejected into space during the explosion of Supernova 1987A.  They charted the interplay between the stellar explosion and the famous “String of Pearls,” a glowing ring almost ten trillion kilometers in diameter encircling the supernova remnant. This ring of material has been energized (heated) by by x-rays from the explosion.

The gas ring is made of material that probably was shed some 20,000 years before the supernova exploded, and shock waves rushing out from the remnant have been brightening some 30 to 40 pearl-like hot spots in the ring — objects that likely will grow and merge together in the coming years to form a continuous, glowing circle. The team’s observations revealed significant brightening in the emissions from the ring of gas from the supernova, particularly in the ultraviolet wavelengths. The brightening in ultraviolet (and other wavelengths) had been predicted based on current thinking about how supernovae interact with material in their immediate neighborhood. Hubble was used because it is a multiwavelength observatory — that is, it’s sensitive to optical, infrared, and ultraviolet (UV)  wavelengths of light.  Earth’s atmosphere interferes greatly with incoming UV, and so using HST (which lies above our atmosphere) is important.

“The new observations allow us to accurately measure the velocity and composition of the ejected ‘star guts,’ which tell us about the deposition of energy and heavy elements into the host galaxy,” said CU-Boulder Research Associate and lead study scientist Kevin France of the Center for Astrophysics and Space Astronomy. “The new observations not only tell us what elements are being recycled into the Large Magellanic Cloud, but how it changes its environment on human time scales.”

In addition to ejecting massive amounts of hydrogen, 1987A spewed helium, oxygen, nitrogen and rarer heavy elements like sulfur, silicon and iron. Such stellar explosions are responsible for a large fraction of elements that are common to other stars, planets — and life.  These include oxygen, carbon and iron — all found in on Earth, in plants and animals. For example, the iron in a person’s blood, comes from supernova explosions.

Supernova 1987A occurred in the Large Magellanic Cloud, a dwarf galaxy that is a close neighbor of the Milky Way. Astronomers around the world rushed to observe it, and they continue to do so today as the remnants of the blast expand across space. “To see a supernova go off in our backyard and to watch its evolution and interactions with the environment in human time scales is unprecedented,” said France.  “The massive stars that produce explosions like Supernova 1987A are like rock stars — they live fast, flashy lives and die young.”

France also pointed out that the energy input from supernovae regulates the physical state and the long-term evolution of galaxies like the Milky Way. Many astronomers believe a supernova explosion near our forming Sun some 4 to 5 billion years ago is responsible for a significant fraction of radioactive elements in our solar system today. “In the big picture, we are seeing the effect a supernova can have in the surrounding galaxy, including how the energy deposited by these stellar explosions changes the dynamics and chemistry of the environment,” said France. “We can use this new data to understand how supernova processes regulate the evolution of galaxies.”

SPACEPORT AMERICA PRESS RELEASE •
FOR IMMEDIATE RELEASE •
SEPTEMBER 2, 2010 •

ARMADILLO AEROSPACE PLANS NASA-FUNDED LAUNCHES FROM SPACEPORT AMERICA

LAS CRUCES, NM – The New Mexico Spaceport Authority (NMSA) has announced that Armadillo Aerospace of Rockwell, Texas, plans to launch three NASA-funded tests of their vertical takeoff and landing rocket technology from Spaceport America this winter.

“These launches mark an important step in NASA’s plan to empower the emerging commercial spaceflight industry to assume a greater role in the nation’s space program,” said Rick Homans, executive director of the New Mexico Spaceport Authority. “Spaceport America is the launch pad for this new industry, and Armadillo’s decision to launch here affirms our important position.”

Armadillo Aerospace is developing new vehicles that can launch small payloads to suborbital “near space”, which NASA defines as altitudes between about 19 and 106 km, and return them safely to earth.

“Armadillo is proud to pioneer reusable rocket technology for the commercial space industry and Spaceport America provides the perfect place for our launches,” said Neil Milburn, Vice President of Program Management at Armadillo Aerospace. “We selected Spaceport America because of its geographic advantages, dedicated staff, technical experience, flexibility and its low cost. We need exactly this kind of support to be successful.”

Milburn said Armadillo will move its test operations to Spaceport America for two NASA-funded CRuSR (Commercial Reusable Suborbital Research Program) flights to 15 kilometers, under the Amateur Class III waiver, and a subsequent fully licensed or permit flight to at least 40 kilometers this winter.

Armadillo’s grant will help fund flights from Spaceport America, and was made possible through NASA’s CRuSR program, which establishes a series of suborbital flights that will yield many benefits to NASA by providing access to 3-4 minutes of microgravity for experimentation, discovery and testing. According to Homans, it’s NASA’s goal to help private firms develop suborbital spacecraft that will eventually provide the nation with much lower-cost and much more reliable access to orbital space. Spaceport America anticipates playing a critical role in the CRuSR program.

Homans added that the Armadillo announcement comes just two weeks after the Federal Aviation Administration (FAA) awarded at least $5 million to New Mexico State University to develop a Center of Excellence for Commercial Space Transportation.

“These announcements, coming one on top of another, are big news for Spaceport America,” Homans said.

Armadillo Aerospace is a leading developer of reusable rocket powered vehicles. Founded in 2000, Armadillo Aerospace has an unequaled experience base with over 200 flight tests spread over a dozen different vehicles. The company has done work for NASA and the United States Air Force, and flown vehicles at every X-Prize Cup and Northrup Grumman Lunar Lander Challenge event, including those held in New Mexico from 2006 to 2008. The firm has plans to provide a platform for civilian access to suborbital space via a recent marketing agreement with Space Adventures, Ltd.

Spaceport America has been providing commercial launch services since 2006. The state-of-the-art launch facility is under construction near Truth or Consequences, New Mexico, and is expected to become fully operational in 2011. Officials at Spaceport America have been working closely with leading aerospace firms such as Armadillo Aerospace, Virgin Galactic, Lockheed Martin, Moog-FTS, and UP Aerospace to develop commercial spaceflight at the new facility. The economic impact of launches, tourism and new construction at Spaceport America are already delivering on its promise to the people of New Mexico.
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(For additional information and images of Spaceport America go to www.spaceportamerica.com

Friday, August 20, 2010

The Astronomer’s Universe with Carolyn Collins Petersen

Star Birth

Best seen Full Screen

This month another look at star birth from the viewpoint of what interests astronomers about this most fundamental process. The first stars came into existence just over 13 billion years ago and the procedures for making stellar objects have been occurring ever since then.  We see it happening in nearly every direction of the universe, in nearly every galaxy that exists.

You would think that such a ubiquitous process would be very well understood by astronomers. In very general terms, we do know the basic outlines of how it is that stars form from a nebula (a cloud of gas and dust) and ultimately end up as bright  self-luminous objects. But, as they always say, the devil is in the details.

What causes that cloud of gas and dust to start down the long road to star formation?  Why do some clouds produce huge numbers of clouds while others form just a few?  Where did the gases and dust in the star forming nebula come from?  What was the event that kicked off the formation of our own solar system?  What really happens in those very dense clouds of gas and dust that we can’t see into, such as those in the famous Pillars of Creation image from HST?

These questions and many others drive astronomers to study star birth regions in the Milky Way and beyond, using new technologies that allow them to peer beyond the clouds of gas and dust nearly to the hearts of stellar nurseries. It’s an exciting field of study that encompasses not just astronomy but astrophysics and chemistry (particularly the chemical interactions in the clouds where stars form).  The study of star birth ultimately also leads to the study of star death because for all the star forming regions we see today, stars had to die and contribute material in order for new generations of stars to form.  This is one of the many reasons that starbirth fascinates astronomers.

Re-post

This month A Green Space – A Green Earth focus on disaster mitigation and early warnings and how space based Earth observations contributes to safe-guard lives and property. See Video

New satellite techniques such as InSAR complement GPS in unraveling in fine details crustal movements of the Earth. ESA’s GOCE gravity measurements from space will add knowledge to our understanding of sub-surface movements leading up to earthquakes. Through observing Earth from space before, during and after earthquakes we improve disaster mitigation and early warnings.

Learn more about earthquakes and the examples mentioned in this episode through the following links:

How does InSAR work?

InSAR used at the L’Aquila, Italy earthquake 2009.

Seismic and Medical Tomography

Global Earthquake Model – A OECD program

Indian Ocean Tsunami Disaster 2004 – A portal for more information at University of Buffalo, NY, USA

Wenchuan, China earthquake 2008 – A portal for maps and geophysical information about the earthquake

Wenchuan, China earthquake 2008 in numbers (in Chinese with map from China Earthquake Adminstration)

L’Aquila, Italy earthquake 2009 in pictures – A collection of images in Boston Globe.

Space geodetic techniques – A portal for more information about space based geodetic techniques.

Re-post

Catch what’s up in our August night sky.

Best seen full screen. Click right button on player control.

Frugal Aliens Might Be Sending in a Cost-Effective Way

The Search for Extra-terrestrial Intelligence (SETI) has been the focus of a dedicated group of scientists for the past 50 years.  The process, developed in the 1960s, involves listening for signals from nearby stars and trying to decipher any type of intentional message from among the noise of space. And, make no mistake about it, space is noisy.

No signals have been found yet, and that has some researchers wondering if there isn’t a better and more cost-effective way to monitor signals.  But, has anybody thought about what sending messages across space might cost a civilization?  Gregory Benford, an astrophysicist at University of California-Irvine is. He’s teamed up with his twin brother James, who is a physicist specializing in microwave technology, to look at the problem from the point of view of the folks on other worlds who we have been hoping were sending messages to us.  Their conclusions, publihsed in the June of the journal Astrobiology, assume that any alien civilization might want to save money and resources and send their messages in the most cost-effective way possible. This means optimizing the use of bandwidth and sending narrowly focused beams that carry pulsed signals in the 1- to 10-gigahertz range.

James Benford likens that approach to being more like Twitter, with its shortened, efficient methodology of sending messages.  James and Gregory (who is also a science fiction writer) have caught the attention of the SETI community with their so-called “Benford Beacons”.  Researchers are taking a look at their current efforts, which focus their receivers on narrow-band input. They’ve come to the conclusion that they may be looking for the wrong kind of signals. The Benfords and a growing number of scientists involved in the hunt for extraterrestrial life advocate adjusting SETI receivers to maximize their ability to detect direct, broadband beacon blasts.

Once that’s done, the next question will focus on where to look for these little beacons. The Benfords suggest star-rich areas of the Milky Way, particularly toward the center where stars are at least a billion years older than the Sun. Those stars might stand a good chance of harboring life of the intelligent variety.

To hear more about these Benford Beacons, watch this video interview with James Benford.

If you’re interested in learning more about all the aspects of SETI, consider attending SETICon, being held August 13-15, 2010. Details at are SETIcon.com.

No… Maybe It’s A Cometary Planet

Astronomers used the Hubble Space Telescope’s Cosmic Origins Spectrograph (COS) to study the ultraviolet-light fingerprints of elements in light streaming away from a star located 153 light-years from Earth. What’s so important in that starlight?  According to astronomer Jeffrey Linsky of the University of Colorado, Boulder, the evidence from the spectrograph shows that there’s a “baked” object orbiting the star.

The chemical elements in the starlight are actually evidence that the planetary atmosphere is being heated by the nearby star and escaping into space. The fleeing atmospheric gases are being swept into a tail, giving the planet — named HD 209458b — a comet-like appearance.

“Since 2003 scientists have theorized the lost mass is being pushed back into a tail, and they have even calculated what it looks like,” said Linsky, who is the leader of the COS study. “We think we have the best observational evidence to support that theory. We have measured gas coming off the planet at specific speeds, some coming toward Earth. The most likely interpretation is that we have measured the velocity of material in a tail.”

The planet is not Earth-like, but instead is more Jupiter-like. It orbits 100 times closer to its star than Jupiter does to the Sun. That gives this roasted planet a very short year — only 3.5 days long.  For this reason, plus its proximity to Earth and the fact that it is one of the few known exoplanets that can be seen passing in front of (transiting) its star, HD 209458b is one of the most intensely scrutinized alien worlds in our part of the galaxy.  The fact that this star transits its star so frequently allowed Linsky and his team to use COS to analyze the planet’s atmosphere as it passed in front of the star.

During a transit, astronomers study the structure and chemical makeup of a planet’s atmosphere by sampling the starlight that passes through it. The dip in starlight because of the planet’s passage, excluding the atmosphere, is very small, only about 1.5 percent. When the atmosphere is added, the dip jumps to 8 percent, indicating a bloated atmosphere.

COS detected the heavy elements carbon and silicon in the planet’s super-hot 2,000 degrees Fahrenheit atmosphere. This detection revealed the parent star is heating the entire atmosphere, dredging up the heavier elements and allowing them to escape the planet.

The COS detection isn’t the first time a Hubble Space Telescope instrument has detected this cometary planet’s atmosphere. The Space Telescope Imaging Spectrograph (STIS) first observed the planet in 2003 and found the first evidence of this world’s evaporating atmosphere.  COS’s followup study gave astronomers much  more detail and is allowing them to study the action in ultraviolet wavelengths.