Study Finds World is Warming…and Cooling

Posted May 5th, 2014 at 8:06 pm (UTC+0)
2 comments

17-210-Skirble-global-warming-An international team of climate researchers says the world’s climate has warmed at an unparalleled rate over the past century, but has also found that this warming hasn’t occurred everywhere at the same rate.

Their research also indicates that some parts of the world actually cooled during the 100-year time period.

The new study, published in Nature Climate Change, is the first to provide a detailed look at trends in global land warming for the last 100 years, according to the researchers Florida State University and the College of Atmospheric Sciences at Lanzhou University in China.

The paper also provides details on exactly when and where different areas of the world started to either warm up or cool down.

To make their findings, the researchers developed an analysis method that reviewed historical records of land surface temperatures from 1900 through the present for the entire world, except Antarctica.

Researchers Zhaohua Wu, Fei Ji, and Eric Chassignet (l-r) led study that  provided the first detailed look at when and where the earth has warmed up and cooled down. (Meredith Field/Center for Ocean-Atmospheric Prediction Studies)

Researchers Zhaohua Wu, Fei Ji, and Eric Chassignet (l-r) led study. (Meredith Field/Center for Ocean-Atmospheric Prediction Studies)

“Global warming was not as understood as we thought,” said Zhaohua Wu, an assistant professor of meteorology at Florida State University, who led the research team.

With their new data analysis method, scientists were able to provide the kind of details that had been missing from previous climate studies.

They said due to limitations of previous analysis methods in climate research, past studies on global warming didn’t provide information on non-uniform warming in space and time.

Their analytical review of historical records showed noticeable warming first started in and around the areas that encircled the Arctic and also the subtropical regions – the area between the 35th parallel in the Northern and Southern Hemispheres and the Tropics of Cancer and Capricorn, which includes parts of North and South Africa, the Middle East, Southern Europe, North and South America, Asia and Australia.

But the area of the world where they found the largest buildup of warming taking place through present times has been in the mid-latitudes of the northern hemisphere such as the US and Canada in North America, most European countries and Asian countries such as parts of China and Russia.

Along with the warming trends, they found cooling had actually occurred in some parts of the world.

This visualization shows a running five-year average global temperature, as compared to a baseline average global temperature from 1951-1980. (NASA GISS)

This visualization shows a running five-year average global temperature, as compared to a baseline average global temperature from 1951-1980. (NASA GISS)

“The global warming is not uniform,” said research team member Eric Chassignet, director of Florida State University’s Center for Ocean-Atmospheric Prediction Studies. “You have areas that have cooled and areas that have warmed.”

As most of the world was warming up between 1910 and 1980, some areas south of the equator near the Andes were actually cooling down, and then afterwards had no change at all until the middle 1990s.

Wu said that the detailed representation of when and where the world has warmed or cooled made possible by their analysis should provide a greater context to global warming research overall.

Animation of researchers findings.

http://www.voanews.com/media/video/1913632.html?nocache=1

Giant Jovian Moon Might Have an Ocean and Ice ‘Club Sandwich’

Posted May 2nd, 2014 at 8:36 pm (UTC+0)
3 comments

Artist concept of possible 'Moonwich' of Ice and Oceans on Ganymede (NASA/JPL-Caltech)

Artist concept of possible ‘Moonwich’ of Ice and Oceans on Ganymede (NASA/JPL-Caltech)

Ganymede is Jupiter’s largest moon; in fact it’s the solar system’s biggest moon.  Now members of the Icy Worlds team at NASA’s Jet Propulsion Laboratory (JPL) think that the giant moon, which is even larger than the planet Mercury, may have several layers of ice and liquid oceans piled atop each other, much like a club or other type of stacked sandwich.

The JPL scientists based their findings on computer models of Ganymede’s makeup.

The research also revealed that the icy moon may have hosted primitive life.

They drew attention to areas of the Jovian moon where water and rock intermingle and said those interactions are important for the development of life.  The researchers pointed out that life on our own planet may have also gotten its start in a similar way.

Some scientists propose that about 3.6 billion years ago, key life-giving elements contained within material that originated deep beneath Earth’s surface bubbled out of hydrothermal ocean vents and eventually developed into our planet’s earliest life forms.

Until these recent findings, it was thought that the rocky sea bottom of Ganymede was covered with ice instead of liquid, which is something that could prevent the development of life.  The computer models the scientists produced for their research also led them to believe that the first layer atop the moon’s core might be salty water.

The Galileo spacecraft snapped this natural color view of Ganymede in 6/96 as it made its first encounter with the Jovian moon. (NASA/JPL)

The Galileo spacecraft snapped this natural color view of Ganymede in 6/96 as it made its first encounter with the Jovian moon. (NASA/JPL)

“This is good news for Ganymede,” said JPL’s Steve Vance, who also led the study. “Its ocean is huge, with enormous pressures, so it was thought that dense ice had to form at the bottom of the ocean. When we added salts to our models, we came up with liquids dense enough to sink to the sea floor.”

Models of Ganymede’s oceans produced in the past led scientists to assume that salt had little effect of a liquid’s properties with pressure. But the JPL team conducted laboratory tests that showed the density of liquids under the same harsh conditions inside of Ganymede were increased with salt.

While some may find it odd that the ocean could be made to be denser with the addition of salt, the researchers suggested an experiment that can be tried at home that will show how this is possible.  Simply add some regular table salt to a glass of water.  You should be able to notice that instead of increasing the volume of liquid within the glass, it shrinks and becomes denser. This is, according to the scientists, because the salt ions attract water molecules.

As the JPL scientists progressed through their computer models they noticed that things got a little more complicated when they took the different forms or phases of ice into consideration.

The cubes of ice you add to your drink to make it colder is referred to as something called “Ice Ih.” It’s lighter than liquid water and is the least dense form of ice.

But you start adding in more pressure and the structure of the ice crystals become much more compact.

Incredibly high pressure, such as what is thought to be found in the deep oceans of Ganymede, produces ice that is so dense that it can actually drop to the bottom of the ocean.  Study scientists believe the densest form of ice on the Jovian moon is “Ice VI”.

Artist concept of a super-Earth exoplanet GJ1214b orbiting its tiny red dwarf sun. Observations from the Hubble Space Telescope show that it is a waterworld enshrouded by a thick, steamy atmosphere. (NASA, ESA, and D. Aguilar/Harvard-Smithsonian Center for Astrophysics)

Artist concept of a super-Earth exoplanet GJ1214b orbiting its tiny red dwarf sun. Observations from the Hubble Space Telescope show that it is a waterworld enshrouded by a thick, steamy atmosphere. (NASA, ESA, and D. Aguilar/Harvard-Smithsonian Center for Astrophysics)

The team added these processes to their computer model and came up with an ocean sandwiched between up to three ice layers that cover the rocky seafloor of Ganymede. The lightest ice makes up the top layer and the bottom layer consists of the saltiest liquid.

The JPL team said that their findings can also be applied to the study of exoplanets or planets beyond our solar system.  Some have proposed that a number of the rocky exoplanets that are more massive than Earth – Super-Earths – are also covered in oceans.

Vance and his colleagues think that scientists conducting laboratory experiments with models similar or even more complex than those they used in their research could help determine whether or not life could exist on these alien “water worlds”.

The study that outlines the JPL team’s findings was published in the journal “Planetary and Space Science.”

Astronomers Capture 3D Images of Mysterious Intergalactic Matter

Posted April 30th, 2014 at 8:05 pm (UTC+0)
2 comments

Lyman alpha blob in emerging galaxy cluster SSA22 imaged with Caltech's Cosmic Web Imager. The arrows show the gas filaments of the IGM flowing into blob. (Christopher Martin, Robert Hurt)

Lyman alpha blob in emerging galaxy cluster SSA22 imaged with Caltech’s Cosmic Web Imager. The arrows show the gas filaments of the IGM flowing into blob. (Christopher Martin, Robert Hurt)

For the first time, 3D images have been captured of a cosmological entity called the intergalactic medium (IGM).  Until now, the structure of IGM had been theoretical.

The discovery could provide astronomers with a new understanding of galactic and intergalactic dynamics.

The images were captured with an instrument built at the California Institute of Technology called the Cosmic Web Imager. The device was installed on the Hale 200-inch telescope at Palomar Observatory near San Diego, California.

IGM is a network or web of thread-like formations of diffuse gases left over from the Big Bang that links all the galaxies in the universe together.

Christopher Martin, professor of physics at Caltech, created and developed the device.

“I’ve been thinking about the intergalactic medium since I was a graduate student,” he said. “Not only does it comprise most of the normal matter in the universe, it is also the medium in which galaxies form and grow.”

The first intergalactic filaments of IGM imaged by Martin’s team were within an area of space occupied by a quasar and something  known as a Lyman alpha blob – considered to be one of the largest objects in the universe – which was found within a developing galaxy cluster.

Caltech's Cosmic Web Imager installed in the Cassegrain cage of the Hale 200 inch telescope at Palomar Observatory. (Matt Matuszewski)

Caltech’s Cosmic Web Imager installed in the Cassegrain cage of the Hale 200 inch telescope at Palomar Observatory. (Matt Matuszewski)

Martin and his colleagues observed one narrow filament that flowed into the quasar.  The astronomers determined that it was about one million light-years long and might be powering the growth of the galaxy that contains the quasar.  The team also found three filaments surrounding the Lyman alpha blob. Measurements indicated the diffuse gas from the filaments was pouring into the blob and affecting its dynamics.

The scientists associated with the Cosmic Web Imager say the device has already spotted one possible spiral-galaxy, three times the size of our Milky Way galaxy, that is still developing.

Planet Outside Solar System Spins Itself Into 8-hour Days

Artist rendering shows the planet orbiting Beta Pictoris. This exoplanet is the first to have its rotation rate measured.  (ESO, L. Calçada/N. Risinger, skysurvey.org)

Artist rendering of Beta Pictoris b orbiting its star. The exoplanet is the first to have its rotation rate measured. (ESO, L. Calçada/N. Risinger)

For the first time, astronomers have been able to measure the rotational speed of an exoplanet.

They found that a day on Beta Pictoris b, a young planet discovered about six years ago, is just eight hours long.

A team of astronomers from Leiden University in the Netherlands used the European Southern Observatory’s Very Large Telescope to make the measurement.

The team found that the planet, which is more than 16 times larger and has 3,000 times the mass of Earth, orbits its sun at a speed of about 100,000 km per hour at its equator.

Compare that to Earth, which rotates at an equatorial velocity of 1,700 km per hour, resulting in 24-hour days.

An annotated view of the Beta Pictoris system, including planet Beta Pictoris b as imaged in 2008 with special equipment mounted on ESO's Very Large Telescope (ESO via Creative Commons)

An annotated view of the Beta Pictoris system, including planet Beta Pictoris b as imaged in 2008 with special equipment mounted on ESO’s Very Large Telescope (ESO via Creative Commons)

“It is not known why some planets spin fast and others more slowly,” says Remco de Kok, co-author of a paper outlining the discovery. “But this first measurement of an exoplanet’s rotation shows that the trend seen in the Solar System, where the more massive planets spin faster, also holds true for exoplanets. This must be some universal consequence of the way planets form.”

Beta Pictoris b orbits Beta Pictoris, a star visible to the naked eye, which is about 63 light-years from Earth. The star and its planet are within the southern constellation of Pictor, which means “the painter’s easel” in Latin.

Beta Pictoris b was also one of the first exoplanets to be directly imaged. Orbiting its star at a distance of about 1,196,782,968 km or 8 times the distance of the Earth from the Sun, it’s also the closest extrasolar planet to its star to be directly imaged.

Coldest-Ever Brown Dwarf Star Discovered

Posted April 28th, 2014 at 6:21 pm (UTC+0)
Comments are closed

Artist's conception of the brown dwarf WISE J085510.83-071442.5. The bright star directly to the right of the brown dwarf is the Sun. (Robert Hurt/JPL, Janella Williams/Penn State University)

Artist’s conception of the brown dwarf WISE J085510.83-071442.5. The bright star directly to the right of the brown dwarf is the Sun. (Robert Hurt/JPL, Janella Williams/Penn State University)

The coldest-ever brown dwarf star has been found about 7 light-years away from Earth and could help scientist learn more about the atmospheres of planets.

Brown dwarfs are objects that are too big to be planets, but too small to be considered stars.  They begin their lives like stars, but since their mass is so low, they are unable to produce the energy needed to be star.

A Penn State University astronomer used NASA’s Wide-field Infrared Survey Explorer (WISE) and Spitzer Space Telescopes to find the icy object dubbed WISE J085510.83-071442.5. Its temperature is between -48 to -13 degrees Celsius, even colder than the average winter temperature of the Arctic.

The WISE and Spitzer also found other brown dwarfs that were at one time the coldest such objects found.  Their temperatures were measured to be around room temperature somewhere between 20 and 23.5 °C.

Locations of star systems that are closest to the Sun and the year they were discovered. WISE J085510.83-071442.5 (top left) is the fourth nearest system to the Sun. (Janella Williams, Penn State University)

Locations of star systems that are closest to the Sun and the year they were discovered. (Janella Williams, Penn State University)

The newly discovered brown dwarf star is the fourth closest star system to the Sun.

“It is very exciting to discover a new neighbor of our solar system that is so close,” said Kevin Luhman, an associate professor of astronomy and astrophysics at Penn State. “In addition, its extreme temperature should tell us a lot about the atmospheres of planets, which often have similarly cold temperatures.”

The astronomers spotted the brown dwarf with the WISE space telescope after conducting a thorough infrared survey of the entire sky. The observers scanned the cosmos up to three times in some areas of the sky.

Infrared observations are one of the only way for astronomers to detect chilly objects like brown dwarf stars.  Unlike visible light telescopes, infrared telescopes pick up on an object’s heat signature no matter how faint it might be. Objects such as the brown dwarf would be invisible to visible light telescopes.

Artist conception of NASA's Spitzer Space Telescope (NASA/JPL)

Artist conception of NASA’s Spitzer Space Telescope (NASA)

The astronomers relied on data from Spitzer’s infrared observations to help them determine the icy brown dwarf’s temperature, and a combination of detections from Spitzer and WISE helped them to assess the object’s distance.

“It is remarkable that even after many decades of studying the sky, we still do not have a complete inventory of the Sun’s nearest neighbors,” said Michael Werner, project scientist for Spitzer at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California.  “This exciting new result demonstrates the power of exploring the universe using new tools, such as the infrared eyes of WISE and Spitzer.”

Artist's concept of the Wide-field Infrared Survey Explorer. (Image: NASA/JPL-Caltech)

Artist’s concept of the Wide-field Infrared Survey Explorer. (NASA)

It’s estimated that the WISE J085510.83-071442.5 dwarf star is between three-to-10 times the mass of Jupiter.

The astronomers say that, with such a low mass, the  brown dwarf could very well have been a gas giant planet, such as our solar system’s outer four planets Jupiter, Saturn, Uranus and Neptune, that had been kicked out of its star system.

Since these types of objects are fairly common in the cosmos, the astronomers have determined that it’s not a planet but a brown dwarf, albeit one of the least massive brown dwarfs that have been found.

Astronauts Warn of Catastrophic Asteroid Strikes

Posted April 23rd, 2014 at 7:25 pm (UTC+0)
5 comments

Asteroid impacting Earth (NASA)

Asteroid impacting Earth (NASA)

Three former astronauts are sounding the alarm about the dangers our planet faces from asteroid impacts and how steps must be taken now to protect against a catastrophic asteroid strike.

The three astronauts included  Ed Lu, who flew into space aboard the space shuttle, as well as a Soyuz spacecraft, to and from the International Space Station. Lu also co-founded the B612 Foundation, an organization dedicated to protecting Earth from potentially disastrous asteroid strikes. The other two astronauts include Tom Jones, a veteran of four space shuttle missions and Bill Anders, who photographed the iconic Earthrise over the desolate moonscape as a member of the 1968 Apollo 8 mission.

Infrasound arrays at the Qaanaaq, Greenland Comprehensive Nuclear Test Ban Treaty Organization's monitoring station. Data used to indicate asteroid strikes in B612 video came from the organization's worldwide network of infrasound monitoring stations that are used for listening for nuclear detonations around the world. (CIBTO via Wikimedia Commons)

Infrasound arrays at the Qaanaaq, Greenland Comprehensive Nuclear Test Ban Treaty Organization’s monitoring station. (CIBTO via Wikimedia Commons)

The trio also presented a new video, produced by the B612 Foundation, which graphically illustrates just how frequently the Earth is hit by asteroids.

The data used to produce the video was provided by the Comprehensive Nuclear-Test-Ban Treaty Organization Preparatory Commission, which operates a network of monitoring stations around the world that is constantly listening for the infrasound signature of a nuclear detonation.

The video shows that in the years 2000 through 2013, there were 26 explosions on Earth due to asteroid impacts.

Trees were knocked down and burned over hundreds of square km by the Tunguska impact event. This image was taken in May 1929 during the Leonid Kulik expedition (Leonid Kulik/Wikimedia Commons)

Trees were knocked down and burned over hundreds of square km by the Tunguska impact event. This image was taken in May 1929 during the Leonid Kulik expedition (Leonid Kulik/Wikimedia Commons)

While most of the asteroids depicted in the video exploded too high in the atmosphere to do any serious damage on the ground, the amount of energy produced by the incoming asteroids was equivalent to 1 to 600 kilotons of TNT.

The atomic bomb that exploded above the Japanese city of Hiroshima in 1945 had an energy impact of 15 kilotons.

The largest and most destructive asteroid impact event in recent history exploded over Tunguska, Siberia in 1908, and is known simply as the Tunguska impact event.

Scientists think it may have been a small asteroid or comet with an energy impact of between 5 to 15 megatons.

A meteorite contrail is seen over a village of Bolshoe Sidelnikovo 50 km of Chelyabinsk on Friday, Feb. 15, 2013. (Photo: AP/Nadezhda Luchinina, E1.ru)

A meteorite contrail is seen over a village of Bolshoe Sidelnikovo 50 km of Chelyabinsk on Friday, Feb. 15, 2013. (AP)

A more recent impact involves a meteor that is thought to have been a near-Earth asteroid that exploded in an air burst over Chelyabinsk, Russia on Feb. 15, 2013.

While our atmosphere absorbed most of the object’s energy, the Chelyabinsk meteor had a pre-atmospheric impact kinetic energy total that was equivalent to approximately 500 kilotons of TNT.

The video also points out other recent asteroid impacts greater than 20 kilotons which occurred in South Sulawesi, Indonesia in 2009, in the Southern Ocean in 2004, and in the Mediterranean Sea in 2002.

Each green dot represents an asteroid in our solar system which can vary in size from very small to large. The green circle indicates Earth's orbit.  Notice the number of asteroids within Earth's orbital path. ((c) B612 Foundation)

Each green dot represents an asteroid in our solar system which can vary in size from very small to large. The green circle indicates Earth’s orbit. Notice the number of asteroids within Earth’s orbital path. ((c) B612 Foundation)

None of the asteroids involved in these explosive events were detected ahead of time by any space-based or Earth-based observatory.

According to Lu, less than 10,000 of the more than one million dangerous asteroids with the potential to destroy an entire major metropolitan area have been found by  existing space or terrestrially-operated observatories.

“Because we don’t know where or when the next major impact will occur, the only thing preventing a catastrophe from a “city-killer” sized asteroid has been blind luck,” Lu said.

 Artist's concept of the B612 Foundation's Sentinel Space Telescope ((c) B612 Foundation)

Artist’s concept of the B612 Foundation’s Sentinel Space Telescope ((c) B612 Foundation)

Among the efforts planned to lessen the odds of our planet someday being struck by a catastrophic asteroid, the B612 Foundation is building the first privately funded Sentinel Space Telescope Mission.

The Sentinel spacecraft is planned for launch in 2018. The infrared space telescope will scan the inner solar system, identify the current and future locations and trajectories of Earth-crossing and potentially harmful asteroids by looking for their “heat signatures”.

According to NASA’s Near Earth Object program, about 10,912 near-Earth objects have been found. Of these near-Earth objects, 862 are asteroids with a diameter of about 1 kilometer or larger and some 1,465 of these objects have been classified as Potentially Hazardous Asteroids.

Speaking at the B612 Foundation event, astronaut Tom Jones said that there could be 100,000 times more of these near-Earth objects out there that haven’t been discovered yet.

B612 Foundation officials said that the early warning system efforts such as their Sentinel mission would give those of us on Earth some time to come up with a plan to prevent deadly asteroids from striking the planet.

B612 Foundation Video Shows How Frequently Earth is Struck by Asteroids

New Dating System Could Reveal Secrets of Earth’s Ancient Climate

Posted April 21st, 2014 at 7:51 pm (UTC+0)
2 comments

Ice sample trench at Antarctica's Taylor Glacier. Ice core samples from this site were analyzed with the Atom Trace Analysis technique at Argonne National Laboratory, Chicago. (Hinrich Schaefer/Oregon State University)

Ice sample trench at Antarctica’s Taylor Glacier. Ice core samples from this site were analyzed with the Atom Trace Analysis technique at Argonne National Laboratory, Chicago. (Hinrich Schaefer/Oregon State University)

Scientists have a new tool in the quest to learn more about Earth’s ancient climate, including the mechanisms that plunged our planet into and out of ice ages.

The new tool is a scientific technique called radiometric krypton dating, which recently allowed researchers to accurately determine the age of a 120,000-year-old Antarctic ice core sample.

Details of this finding were published by the Proceedings of the National Academies of Science (PNAS).

One of the most important steps for scientists investigating past climatic events is the ability to find polar ice samples that date back as far into time as possible. These ice samples contain frozen bubbles of ancient air that can be analyzed in a laboratory, allowing scientists to reconstruct Earth’s climate history.

“The oldest ice found in drilled cores is around 800,000 years old and with this new technique we think we can look in other regions and successfully date polar ice back as far as 1.5 million years,” said Oregon State University’s Christo Buizert, lead author of the PNAS paper. “That is very exciting because a lot of interesting things happened with the Earth’s climate prior to 800,000 years ago that we currently cannot study in the ice core record.”

Like the well-known carbon-14 dating system used to determine the age of organic materials such as wood, Krypton dating also measures the decay of a radioactive isotope which is known to have a constant and well-known decay rate, and compares it to a stable isotope – an isotope that doesn’t automatically undergo radioactive decay.

However, unlike carbon-14 dating, which was developed in the late 1940s, krypton is a noble gas that is stable, doesn’t interact chemically, and has a half-life of around 230,000 years. Scientists have found that the carbon dating system doesn’t work well on ice samples because the carbon-14 isotope is produced within the ice itself by cosmic rays and is only able to date material to about 50,000 years ago.

Ice core driller Tanner Kuhl with the blue ice drill on Taylor Glacier in Antarctica. The field camp is visible in the background. (© Xavier Fain/Oregon State University)

Ice core driller Tanner Kuhl with the blue ice drill on Taylor Glacier in Antarctica. The field camp is visible in the background. (© Xavier Fain/Oregon State University)

According to the researchers, Krypton is  also produced by cosmic rays that bombard the Earth but is then stored within air bubbles that are trapped inside Antarctic ice. Krypton produces two isotopes that help scientists perform the dating process: one is a radioactive isotope called krypton-81, which has a very slow decay time, and the other is krypton-83, which is a stable isotope that does not decay.  Scientists are able to determine the age of the ice by comparing the percentage of stable isotopes (krypton-83) to the radioactive isotopes (krypton-81).

The researchers said that the radio-krypton dating technique has be around for more than 40 years, but it wasn’t until 2011 when scientists at the Argonne National Laboratory in Chicago developed an innovative method, named the Atom Trap Trace Analysis (ATTA), that radiometric krypton dating of water and ice became possible.

For their ice core dating experiment, researchers melted several 300-kilogram lumps of ice that were retrieved from the Taylor Glacier in Antarctica, in order to release the air stored in the bubbles. The air from the ice bubbles was sent to scientists at the University of Bern, Switzerland, who isolated krypton from the air samples. The krypton was then sent to the Argonne National Laboratory for an Atom Trap Trace Analysis, which revealed that the glacier samples to be 120,000 years old.

With this technique to help them with their work, researchers say their new challenge is to find some of the oldest ice in Antarctica, something that isn’t as easy as it may sound.

Scientists use a pulley system to load 25-kilogram ice cores into the melter setup. Scientists used the melter to extract air from bubbles formed in the ice.  The air samples were sent to a lab for analysis which indicated the samples to be 120,000 years old. (© Vasilii Petrenko/Oregon State University)

Scientists use a pulley system to load 25-kilogram ice cores into the melter setup. (© Vasilii Petrenko/Oregon State University)

“Most people assume that it’s a question of just drilling deeper for ice cores, but it’s not that simple,” said Edward Brook, an Oregon State University geologist and co-author on the study. “Very old ice probably exists in small isolated patches at the base of the ice sheet that have not yet been identified, but in many places it has probably melted and flowed out into the ocean.”

According to Buizert, it’s important that Earth’s climate be reconstructed as far back as 1.5 million years because it will help scientists learn more about a change in the number of ice ages that took place in what is called the Middle Pleistocene transition.  While scientists think Earth has shifted in and out of ice ages every 100,000 years for the past 800,000 years, evidence suggests the planet entered and exited from ice ages much more frequently before that time – at every 40,000 years.

“Why was there a transition from a 40,000-year cycle to a 100,000-year cycle?” Buizert said. “Some people believe a change in the level of atmospheric carbon dioxide may have played a role. That is one reason we are so anxious to find ice that will take us back further in time so we can further extend data on past carbon dioxide levels and test this hypothesis.”

NASA Lunar Explorer Has Smashing End

Posted April 18th, 2014 at 4:52 pm (UTC+0)
Comments are closed

Artist's concept of LADEE passing over the lunar surface (NASA)

Artist’s concept of LADEE passing over the lunar surface (NASA)

NASA’s Lunar Atmosphere and Dust Environment Explorer, or LADEE mission had a smashing ending early Friday morning when the US space agency crashed the spacecraft into the moon’s surface.

The ground controllers, monitoring the spacecraft’s operations from NASA’s Ames Research Center in Moffett Field, California, confirmed that it impacted the lunar surface as planned sometime between 2130 and 2222 UTC on Friday (4/18/14).

One of the final images taken by LADEE as it orbits the moon shows a minor lunar mountain range, Montes Agricola and the flat-floored crater Raman. (NASA Ames)

One of the final images taken by LADEE, as it orbits the moon, shows a minor lunar mountain range, Montes Agricola and the flat-floored crater Raman. (NASA Ames)

Mission officials said that LADEE didn’t have enough fuel to remain in an ongoing lunar orbit or sustain its science operations.  And, since the spacecraft’s orbit was already naturally decaying following the mission’s final science phase earlier this month, it was decided that it would be intentionally sent down onto the lunar surface.

Flying at less than 2 kilometers above the lunar surface, LADEE mission specialists said that the final science phase allowed them to gather some very unique measurements.

NASA said that as it impacted the moon, the vending machine-sized LADEE spacecraft heated up several hundred degrees and broke apart or vaporized.  The space agency believes that if any material remained after crashing, it’s likely buried in the moon’s shallow craters.

“At the time of impact, LADEE was traveling at a speed of 3,600 miles per hour – about three times the speed of a high-powered rifle bullet,” said Rick Elphic, LADEE project scientist at Ames. “There’s nothing gentle about impact at these speeds – it’s just a question of whether LADEE made a localized craterlet on a hillside or scattered debris across a flat area. It will be interesting to see what kind of feature LADEE has created.”

A Minotaur V rocket carrying the Lunar Atmosphere and Dust Environment Explorer lifts off from NASA's Wallops Flight Facility in Virginia on Friday, Sept. 6, 2013. (NASA/Chris Perry)

A Minotaur V rocket carrying the Lunar Atmosphere and Dust Environment Explorer lifts off from NASA’s Wallops Flight Facility in Virginia on Friday, Sept. 6, 2013. (NASA/Chris Perry)

LADEE was launched from NASA’s Wallops Flight Facility in Virginia on September 7, 2013 from NASA’s Wallops Flight Facility in Virginia.  The spacecraft entered lunar orbit on October 6, 2013 and started to gather data on November 10, 2013. In January NASA decided to extend the LADEE mission by an extra month after it finished its very successful primary science phase which took place earlier this month (April 2014).

Throughout its mission LADEE was able to collect some very comprehensive information about the lunar atmosphere’s structure and composition.

NASA scientists continue to pore through the data gathered throughout the lunar spacecraft’s mission and are hoping that it will provide an answer to a question that has puzzled many since the Apollo moon missions of the late 1960’s early 1970’s. Was the pre-sunrise glow that was observed just above the moon’s horizon caused by lunar dust that had been electrically charged by sunlight?

Thousands of people from around the world shared in the final part of LADEE’s mission by taking part in a NASA sponsored internet contest called “Take the Plunge”.  The contest challenged participants to guess the date and time the spacecraft would crash into the moon. Those who provided correct answers will win a digital congratulatory certificate.

“LADEE was a mission of firsts, achieving yet another first by successfully flying more than 100 orbits at extremely low altitudes,” said Joan Salute, LADEE program executive, at NASA Headquarters in Washington. “Although a risky decision, we’re already seeing evidence that the risk was worth taking.”

Video conception of LADEE’S final moments (NASA/Ames)

Study: Air Pollution Over Asia Found to Impact Global Weather

Posted April 16th, 2014 at 8:01 pm (UTC+0)
3 comments

Cars drive on the Three Ring Road amid the heavy haze in Beijing February 26, 2014. China's north is suffering a pollution crisis, with the capital Beijing itself shrouded in acrid smog. Authorities have introduced anti-pollutionpolicies and often pledged to clean up the environment but the problem has not eased. (REUTERS/Jason Lee)

Cars drive on the Three Ring Road amid the heavy haze in Beijing February 26, 2014. (REUTERS/Jason Lee)

Researchers from Texas, California and Washington recently compared air pollution data provided by the Intergovernmental Panel on Climate Change for the years 1850 through 2000 and found that human-made atmospheric particulates (aerosols) from Asia are having an impact on the Pacific storm track, which is a critical driver of global atmospheric circulation that influences weather over most of the world.

The researchers took this historical data and fed it into an advanced global climate model (GCM), a computer model of the general circulation of Earth’s atmosphere, to produce two climate scenarios. One of these scenarios reflected conditions of 1850, considered to be a time period before the industrial era.  The other represented the conditions of 2000, or present time.

Writing in a recent edition of the Proceedings of the National Academy of Sciences (PNAS), the researchers from Texas A&M University, the Pacific Northwest National Laboratory in Richland Washington, the University of California at San Diego and NASA’s Jet Propulsion Laboratory compared the results of the two scenarios and found that human-made aerosols (particulates) overwhelmingly impact cloud formations and mid-latitude cyclones, also called extra tropical cyclones, that are usually associated with the Pacific storm track.

The Pacific storm track transports heat and moisture along its path and the researchers said that they have found an increase in the transfer of heat and moisture that appears further along the storm track, which they said means that the Pacific storm track is intensified because of the discharge of Asian air pollution.

Recent research has shown that atmospheric aerosols affect the world’s climate by dispersing or absorbing the sun’s radiation and by changing the formation of clouds.

Scientists have expressed concern about the rising levels of these particulates in the atmosphere because of the possible effects they could have on regional to worldwide atmospheric circulation.

“There appears to be little doubt that these particles from Asia affect storms sweeping across the Pacific and subsequently the weather patterns in North America and the rest of the world,” said Renyi Zhang from Texas A&M’s Department of Atmospheric Sciences, one of the study’s authors.

Animation of activity along the Pacific storm track (Geophysical Fluid Dynamics Laboratory/NOAA)

Simulation of activity along the Pacific storm track (Geophysical Fluid Dynamics Laboratory/NOAA)

Zhang said that the results in the two scenarios produced by the climate model used by his team clearly indicate that aerosols made by human activities from “fast-growing Asian economies” not only impact the formation of storms but also global air circulation along the Pacific storm track.

The researchers also found that the increased pollution from Asia tends to make storms over the Pacific deeper, stronger and more intense, producing more precipitation.

“Our results support previous findings that show that particles in the air over Asia tend to affect global weather patterns,” Zhang said.  “It shows they can affect the Earth’s weather significantly.”

Scientist 99% Sure Global Climate Change is Man-Made

Posted April 14th, 2014 at 7:16 pm (UTC+0)
9 comments

A Canadian physicist says his studies have all but completely ruled out the premise that global warming throughout the industrial era has not been merely a natural fluctuation in Earth’s climate, as some have been claiming.  The assertion was made after the scientist analyzed temperature data from as far back as 1500.

McGill University study says that there's a 99% chance that global climate change is man-made (otodo via Flickr/Creative Commons)

McGill University study says that there’s a 99% chance that global climate change is man-made (otodo via Flickr/Creative Commons)

“This study will be a blow to any remaining climate-change deniers,” said study author Shaun Lovejoy who is also a professor of physics at McGill University in Montreal. “Their two most convincing arguments – that the warming is natural in origin, and that the computer models are wrong – are either directly contradicted by this analysis, or simply do not apply to it.”

Published in a recent edition of the journal Climate Dynamics, the study, based on statistical analysis of historical data rather on complex computer models used in previous studies, provides a new perspective to the question of what is behind global warming trends.

Lovejoy said that his analysis led him to conclude “with confidence levels great than 99%, and most likely greater than 99.9%,” that global warming since 1880 has been mostly caused by man-made emissions from the burning of fossil fuels and long-term temperature variations not caused by nature.

The historical temperature data Lovejoy used for times prior to the industrial era (before 1760) were estimates that were made from “multi-proxy climate reconstructions” that had been developed by scientists in recent years.

The climate reconstructions took into consideration a variety of natural indicators such as information from tree rings, ice cores, and lake sediments.

For his data from the industrial era, Lovejoy used levels of carbon-dioxide produced by the burning of fossil fuels as a representation for all human caused climate changes, since there has been a close relationship between the world’s economic activity and the release of greenhouse gases and particulate pollution.

“This allows the new approach to implicitly include the cooling effects of particulate pollution that are still poorly quantified in computer models,” said Lovejoy.

This visualization shows a running five-year average global temperature, as compared to a baseline average global temperature from 1951-1980. (NASA GISS)

This visualization shows a running five-year average global temperature, as compared to a baseline average global temperature from 1951-1980. (NASA GISS)

Lovejoy said that his findings complement those made in a report just released by the UN’s IPCC.  He said that his study predicted, with 95% confidence, that doubling the carbon-dioxide levels in the atmosphere would increase global temperatures between 1.9 and 4.2 degrees Celsius.  The IPCC’s prediction puts the rise in temperature between 1.5 to 4.5 degrees Celsius if atmospheric carbon-dioxide levels double.

“We’ve had a fluctuation in average temperature that’s just huge since 1880 – on the order of about 0.9 degrees Celsius,” said Lovejoy. “This study shows that the odds of that being caused by natural fluctuations are less than one in a hundred and are likely to be less than one in a thousand.”

Astronomers May Have Spotted A Moon Orbiting an Extrasolar Planet

Posted April 11th, 2014 at 7:32 pm (UTC+0)
1 comment

An international team may have discovered the first exomoon orbiting a planet in a distant solar system such as what's illustrated here in this artist rendition. (NASA/JPL/Cal-Tech)

An international team may have discovered the very first exomoon orbiting a planet in a distant solar system such as what’s illustrated here in this artist rendition. (NASA/JPL/Cal-Tech)

According to NASA, more than 1,000 extrasolar planets have been confirmed in recent years. There are also thousands more potential planets beyond our solar system that are waiting to be discovered.

Now, an international group of astronomers think they may have found the first exomoon, or moon circling an exoplanet, some 1,800 light years away from Earth.  This possible planet/moon system has been dubbed MOA-2011-BLG-262.

Then again, what the astronomers saw just might be some other kind of object, since they said it’s impossible to confirm its presence.  Nonetheless the scientists call their finding a “tantalizing first step” in the search for other exomoons.

The researchers said that they made their discovery by watching a chance encounter of objects in our galaxy, something that can only be observed once.

“We won’t have a chance to observe the exomoon candidate again,” said David Bennett of the University Of Notre Dame, lead author of a new paper published in the Astrophysical Journal that outlines the discovery. “But we can expect more unexpected finds like this,” he adds.

The research was led by a scientific consortium called the Japan-New Zealand-American Microlensing Observations in Astrophysics (MOA) and the Probing Lensing Anomalies NETwork (PLANET) programs.

Using telescopes located in New Zealand and Tasmania, the research team took advantage of an astronomical phenomenon that’s known as gravitational microlensing.

For example, whenever a nearby star passes directly between Earth and a more distant star, the gravitational field of the closer star will bend and focus the light of that distant star much like a lens in an optical telescope.

...or could the discovery be that of a distant solar system, containing an exoplanet, with a mass about 18 times that of Earth, orbiting a small, dim star  such as what's illustrated here in this artist rendering (NASA/JPL-Caltech)

…or could the discovery be that of a distant solar system, containing an exoplanet having a mass about 18 times that of Earth, orbiting a small, dim star such as what’s illustrated here in this artist rendering (NASA/JPL-Caltech)

If the star closest to Earth should happen to have a planet orbiting it, the scientists said that the planet would serve as a secondary lens that would further brighten or dim the distant object’s light even more.

Through careful analysis of these brightening/dimming events, the astronomers then can determine the mass of the closer star relative to its orbiting planet.

But the astronomers point out that sometimes the object closest to earth may not be a star, but a free-floating planet with a moon circling it. In this case researchers might then be able to measure the mass of the planet relative to its orbiting moon.

While they haven’t been successful so far, astronomers have been trying to locate exomoons orbiting distant planets by using other means, such as data provided by NASA’s Kepler mission.

For the research that led to this new discovery, the nature of the objects that were closest to Earth weren’t really clear to the astronomers.

They said that the ratio of the larger object to its smaller companion is 2,000 to 1 which could mean that the two objects could either be a small, dim star that’s orbited by a planet about 18 times the mass of Earth, or the pair could be a planet that is more massive than Jupiter circled by a moon with a mass that’s less than Earth.

The research team said that they have no way of telling which of the two circumstances is correct.

“One possibility is for the lensing system to be a planet and its moon, which if true, would be a spectacular discovery of a totally new type of system,” said Wes Traub, chief scientist for NASA’s Exoplanet Exploration Program office at the Jet Propulsion Laboratory in Pasadena, California.  Traub, who wasn’t involved with the international team’s studies, also said that “The researchers’ models point to the moon solution, but if you simply look at what scenario is more likely in nature, the star solution wins.”

The astronomers said to get a true answer in determining whether or not they observed an exomoon and not another star system they would need to figure out the actual distance to the circling twosome.

The Microlensing Observations in Astrophysics (MOA) telescope dome located atop Mount John on New Zealand's South Island (Aidan/ASGW via Flickr/Creative Commons)

The Microlensing Observations in Astrophysics (MOA) telescope dome located atop Mount John on New Zealand’s South Island (Aidan/ASGW via Flickr/Creative Commons)

A pair of objects closer to Earth that are low in mass, according to the astronomers, will produce the same kind of brightening event as one that would be produced by two more massive objects located farther away. But unfortunately once the observed brightening/dimming event is over; it’s very difficult for the scientists to take the needed additional measurements to calculate the distance.  That means the actual identity of what may or may not be an exomoon will remain a mystery.

The astronomers said that perhaps sometime in the future, it just may be possible to acquire these distance measurements during lensing events by using, for example, NASA’s Spitzer and Kepler space telescopes.

If it turns out that this sighting is actually a real exomoon that’s orbiting a free-floating planet, the astronomers think that the planet may have been kicked out of a young planetary system, bringing its orbiting moon along for the ride as a travel companion.

About Science World

Science World

Science World is VOA’s on-air and online magazine covering science, health, technology and the environment.

Hosted by Rick Pantaleo, Science World‘s informative, entertaining and easy-to-understand presentation offers the latest news, features and one-on-one interviews with researchers, scientists, innovators and other news makers.

Listen to a Recent Program

Listen Sidebar

Broadcast Schedule

Broadcast Schedule

Science World begins after the newscast on Friday at 2200, Saturday at 0300, 1100 and 1900 and Sunday at 0100, 0400, 0900, 1100 and 1200.

Science World may also be heard on some VOA affiliates after the news on Saturday at 0900 and 1100. (All times UTC).

Contact Us

E-Mail
science@voanews.com

Postal Mail
Science World
Voice of America
330 Independence Ave., SW
Washington, DC 20237
USA