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Archives – September, 2010

How Hot Was Summer 2010?

Summer of 2010 has experienced some extremely severe temperatures and drought like conditions especially in Eastern Europe, Russia and in some parts of Eastern USA. So how hot was summer of 2010? Was it the hottest summer globally or hot summers of Russia were more of local anomalies? NASA GISS has come up with analysis of measured temperature during Jun-Aug 2010 and can be seen in the above plot. The plot shows temperature anomalies as compared to base average temperature during 1951-1980. From the plot, its clearly seen that two region in the globe experienced severe hot summers namely Eurasia region and Antarctic Peninsula. So how were these temperature anomalies as compared to last year, lets have a look:

As can be seen from the 2009 temperatures, severe temperature anomalies like summers of Russia were not there in 2009. But what does that mean in terms of Global temperature trend, which was hotter: summer of 2009 or 2010?

Globally, 2010 was the 4th warmest summer in GISS’s 131-year-temperature record. The summer of 2009 was the 2nd warmest. The slightly cooler 2010 temperatures were primarily the result of a moderate La Niña replacing a moderate El Niño in the Pacific Ocean. Note in 2010 that much of the eastern Pacific, the west coasts of North and South America, and much of Antarctica were cooler than the long-term mean. Temperatures were extremely warm in western Russia and the Antarctic Peninsula. The unusually warm summer temperatures in the U.S. and Eurasia created the impression of global warming run amuck; last winter’s unusually cool temperatures created the opposite impression. But extrapolating global trends based on one or two regions can be misleading.

“Unfortunately, it is common for the public to take their most recent local temperature anomaly as indicative of long-term climate trends, ” James Hansen from NASA GISS noted. “People need to understand that the temperature anomaly in one place in one season has limited relevance to global trends. ” [NASA ESO]

So what it implies is that summer of 2010 was hot but it’s severity was dependent on where you lived. It also means that local temperature anomaly has limited relevance to global temperature trends. But that doesn’t  imply that extreme local temperature absurdities have nothing to do with global temperature trends but before jumping to any conclusions one has to look into long term statistics and trends. If we take a look at average data of past 10 years or so, we might see ups and downs in temperatures but in a long run there is a clear trend of temperature rise.

Data and Analysis credit: NASA ESO | GISS

Leave a Comment September 30, 2010

Climate Change Debate Visualized

David McCandless from Information is Beautiful has again come up with an awesome visualization, this time about climate change debate: believers vs deniers. It’s very informative sans any technical jargon which will be beneficial to people without much knowledge about climate science. You can click on the image to see the image in full size, which will make reading much easier.

Leave a Comment September 30, 2010

Sad Picture of The Day

The picture is sad and disturbing. They need to have books in their hands not spade, cricket ball not stones and pebbles. The picture was taken at one of the construction sites in front of Jawahar Lal Nehru stadium, New Delhi during Jan 30, 2010, the month India celebrates Republic Day. I am not sure if the construction site was related to Commmonwealth Games, but its very much possible that it was. Commonwealth games brought many migrant workers to New Delhi looking for work and with them they also brought their children and they could be seen working in these sites and many organizations tried to help out these children and families. Even Asha for Education UFlorida chapter recevied a proposal from one of the NGOs for these kids but due to various reasons the project couldn’t be funded, one of them being lack of volunteer bandwidth. Kids working for bread and milk, its sad 🙁 If this picture stirs you inside, do join any of your nearby organization which works for children and do whatever minimum you can do. Committed volunteers needed!!

“We must be the change we wish to see in the world”- Gandhi
 

Picture credit: Daniel Berehulak/Getty Images/ Boston.com Bigpicture

Leave a Comment September 30, 2010

Earth-like Exoplanet Found 20 Light Years Away

Astronomers have found an exoplanet, Gliese 581g, 20 light years away from us which might have right conditions for sustaining life or in other words might be possibly habitable. In recent years study of exoplanets have gained lots of momentum to find earth-sun like systems. Till now there are around 500 known exoplanets and more will be discovered in near future. The exoplanet system mentioned here consists of a  red dwarf star  Gliese 581 which is about 20.5 light years away from earth. Till now six planets have been discovered in this system which has remarkably close to circular orbits like our solar system. So what makes the discovery of this planet, Gliese 581g, so remarkable? Well, it’s one of the exoplanets discovered which is believed to lie in Goldilocks zone or habitable zone where liquid water might exist.

In order for life to exist, the planet must neither be too far nor too near form it’s sun. It must have sufficient gravity to hold the atmosphere and regulate the temperature of the planet. Gliese 581 star-planet system have received lots of attention in recent years and other planets from the system have also been in such discussion. Here you can see the G581 planet-sun system showing the possible orbits of all the six planets as compared to our solar system which are shown in dotted lines. The blue one is earth’s orbit, while green and red are Venus and Mercury. What’s interesting to observe is  the circular nature of orbits and its close similarity to our solar system.  The fourth black orbit from the center is the planet under discussion in this article. AU in the plot represents Astronomical Units which is equal to distance of sun from earth.

Some other details about this exoplanet. The mass of the planet is about 3.1 times the mass of earth and orbits in 36.6 days at a distance of 0.146 AU from it’s sun. This distance is pretty close if it was our Sun, but this particular star is less bright than our sun, just 1% as bright as our Sun, so this distance is perfect to make it neither too hot or cold. 3 times the mass of earth implies, that the planet has sufficient density to hold the atmosphere which would in turn retain greenhouse gases for regulating the temperature. One thing to note here is that measurements were done using Doppler shift method which due to technique limitations can only give a lower limit on the size and mass of the planet, so this planet can be much more bigger than 3 times mass of earth. Larger mass is good to hold atmosphere but too large a size can create a very dense atmosphere and heat up the planet extensively, case in point Venus. The astronomers estimated average surface temperature based on the size, density, distance from sun etc and estimated it be in the range of 236-258K , which is pretty good. Overall, an interesting finding and a very exciting exoplanet system to study and understand in near future.

Article:The Lick-Carnegie Exoplanet Survey: A 3.1 M_Earth Planet in the Habitable Zone of the Nearby M3V Star Gliese 581, arXiv:1009.5733v1[astro-ph.EP]

Plot credit:Authors of the article, arXiv.org

Picture credit:Wikimedia Commons- Compariosn of Gliese Exoplanet system with Earth and Neptune

1 Comment September 30, 2010

Plasma-particle Interactions in Laser-induced Plasma

 Another paper came out today, well its my paper so I think I should write a little bit about it :). The study focuses on plasma-particle interactions in laser-induced plasmas. In this study, we tried to understand the fundamentals of dissociation and diffusion process in laser-induced plasmas starting from as early as 250 ns after the plasma is formed. In this study we also estimated diffusion coeffcient of Hydrogen atom. I will  write in detail later but as of now here is the abstract of the article:   

 Study of analyte dissociation and diffusion in laser-induced plasmas: implications for laser-induced breakdown spectroscopy     

Prasoon K. Diwakar, Sebastian Groh, Kay Niemax and David W. Hahn
J. Anal. At. Spectrom., 2010, Advance Article
DOI: 10.1039/C0JA00063A, Paper
   

Plasma–particle interactions are explored through the introduction of single microdroplets into laser-induced plasmas. Both spectroscopic analysis and direct imaging of analyte atomic emission are used to provide insight into the various fundamental processes, namely desolvation, atomization, and atomic diffusion. By doping the 50 µm droplets with Lu, Mg or Ca, the analyte excitation temperature and the ion-to-neutral emission ratio are explored as a function of plasma residence time following breakdown. The data suggest a change in the local plasma conditions about the analyte atoms around 15–20 µs following breakdown, which may be interpreted as an overall transition from localized (i.e. perturbed) plasma conditions to the global (i.e. bulk) plasma conditions. A direct assessment of the hydrogen atomic diffusion coefficient following analyte desolvation reveals a value of 1.7 m2 s−1 in the first 250–500 ns. This value is in good overall agreement with a theoretical analysis and with an analytical treatment of a surface source of hydrogen atoms. In contrast, calcium emission is only observed beyond about 1 µs, with a diffusion coefficient at least an order of magnitude below the hydrogen value. The temporal H and Ca emission data suggest that water vaporizes first, leaving an ever increasing Ca analyte concentration until finally, with nearly all water desorbed, the Ca fraction is vaporized. Overall, the data support the conclusion that finite time-scales of heat and mass transfer play an important role in localized plasma perturbations in the vicinity of the analyte, which has important implications for the LIBS analyte signal.   

Leave a Comment September 29, 2010

Picture of The Day: Fall Colors

Picture credit: AP Photo/Robert F. Bukaty/Boston.com Big Picture. A maple tree shows its fall colors on Friday, September 17th, 2010, in Woodstock, Maine.

Leave a Comment September 29, 2010

Hawking Radiation Observed

In a very recent study, researchers from Italy have claimed to observe the elusive  Hawking radiations by creating a miniature analog of black hole in the lab. The study which is going to be published in Physical Review Letters would be the first study to observe it after theoretical details were first presented by Stephen Hawkings in 1974.  He predicted that instead of taking in everything, blackholes can also emit thermal radiations. Many have tried to observe the phenomena but have failed so far. This results of this study will be scrutinized and debated in the scientific community in coming days. The experimental set up consisted of high energy ultrashort laser pulses which was focused onto a fused silica glass to create gravitational analogue of black holes.

Article:  Hawking radiation from ultrashort laser pulse filaments, Belgiorno et. al. arXiv:1009.4634v1 [gr-qc]

Picture credit: Wikimedia Commons | Used under creative commons license

Leave a Comment September 29, 2010

Enceladus And It’s Icy Mystery

 

What you see above are the ice plumes erupting from surface of Saturn’s sixth largest moon Enceladus. The image was taken by Cassini probe as it flew by the moon during 2009. Not until 2005 these ice geysers were known to scientists. During 2005, Cassini space probe first detected existence of these geysers along with magnetic field distortions. Since then various studies have been done to understand the source of these plumes but still the source remains a mystery. Scientists are interested in Enceladus as they want to know if there is a vast ocean of liquid water beneath the icy surface which might show some signs of life. As compared to other cellestial bodies of similar size and distance from the sun it is much warmer and uncommonly very active which makes the study of this particular moon very interesting.  The ice and water plumes escape the gravity of the moon and ultimately feed the E ring of Saturn.

Scientists have been studying if these plumes contain any traces of Sodium which might bolster the claim that there is a liquid ocean beneath the surface. If there is a sub-surface liquid ocean then the water will come in contact with the rocks and sodium from the rocks will mix with the liquid water. The results of this study has been mixed. One group found the presence of Sodium in the E ring of Saturn, while the other didn’t find any presence of Na when directly studying the plume. So the questions still remains unanswered. Scientists also claim that even if the presence of Sodium was confirmed , that would not still prove that there is liquid water ocean beneath.

One of such alternate models suggests that reservoirs of clathrates — gassy molecules locked up in the lattice of another molecule — exist below the surface. As tectonic plates in the crust move and collide, the crust fractures and these clathrates release gases, which carry up ice particles with them to form the icy plumes. These ice particles could carry up salt as well, says Susan Kieffer a geologist at the University of Illinois at Urbana-Champaign. “Sodium isn’t the proof of a liquid ocean,” she says. “Sodium can be locked up in the ice of an icy clathrate model.” [Nature News]

One of the studies also found some Ammonia in the plume which might suggest that ammonia, which is an antifreeze, keeps the water in liquid state beneath the surface.  There is a lot of ambiguity and hopefully recent Cassini fly-by (Aug-Sep 2010) will provide some more insight.

Picture Credit: NASA/JPL/Space Science Institute

1 Comment September 29, 2010

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