Time to restart my blog now! Time to analyze and discuss numerous scientific stories, share some pictures, videos. While the web address of this blog remains same, my physical location has changed. I have moved to Purdue University at West Lafayette, Indiana where I will be be doing ultra-fast spectroscopy to understand laser and matter interaction. This week, for the first time I operated femtosecond laser and was able to create a plasma Now just thinking of creative ways to use this new scientific tool I am learning. So, Science Is Beautiful-Season 2 starts from today with pictures from Purdue University after weekend snowfall.
Last night’s The Daily Show was awesome as always. Take a look at the video and here is a word of caution: don’t let any scientist con you into believing in evolution or global warming or vaccination or any other “science junk”.
It’s been a while I posted something, consider this a semi-hiatus from blogging. I will try to post something from time to time. I have posted several posts on Auroras. Here is another one with video and pictures taken by astronauts on ISS while passing over Indian Ocean on Sep 17th 2011. They took several images and compiled a video which shows spectacular Aurora display. This particular Aurora display was a result of Coronal Mass Ejection event which occurred in the Sun on Sep 14th 2011, leading to stirring of the earth’s magnetic field and excitation of nitrogen and oxygen molecules in earth’s atmosphere. Greenish part of the Aurora glow is contributed by emission from excited oxygen molecule while blue or purple glow is from nitrogen molecule. Enjoy the Video. Towards the end of the video you can notice some specks and bright glows on earth’s surface which are infact forest wild fires and agricultural fires in Australia.
Hurricane Irene spanned from Caribbean to Canada and lasted for more than a week. NASA/NOAA satellite GOES-13 kept a track of the hurricane and NASA posted a video of the hurricane dating Aug 21st to Aug 29th which covers almost entire life-span of the hurricane. In the video you can see the formation of eye (at about 30 seconds in the video). Right after the formation of eye, you can see a burst of white clouds on the right of the eye which then merges with the core of the hurricane. This burst is due to warm air rising the clouds , also called as overshooting tops, and resulting in severe rainfall. Hurricane Irene at it’s strongest was a category 3 hurricane and turned out to be one of the top ten most destructive hurricanes in the history of US since 1980. About 27 lives were lost, entire transportation system in east coast was affected and more than 5 million people lost power.
While people are enjoying today one of the longest lasting lunar eclipse since 2000 (about 100 minutes long), let’s watch this beautiful video created by folks at NASA Goddard Space Flight Center (see below) using data collected by Lunar Orbiter Laser Altimeter (LOLA) aboard the Lunar Reconnaissance Orbiter (LRO). In the video you can see various phases and movement of moon during the course of one year; one month of movement has been compressed into 12 seconds. As we know, we are able to see only one face of the moon from earth (moon and earth are phase-locked– rotation time of moon is same as it’s revolution time around the earth- about 27 days), in the video it is clearly evident that only one side is visible to us. Since we get to see the moon from different angles owing to it’s tilt and elliptical shape of the orbit, in the video it appears to us as if moon is wobbling. In technical terms we call that wobbling as “liberation”. Because of liberation, we are able to see little bit more than half of the moon’s surface, close to 60%. Due to elliptical orbit, moon also appears to rock back and forth from us (perigee- nearest position, apogee- farthest position). You can also observe different phases of moon such as new moon and full moon and their variations in different months. Enjoy the video, I will be uploading some cool videos or pictures from today’s lunar eclipse event later on.
Video/Image credit: NASA/Goddard Space Flight Center Scientific Visualization Studio
In a new study published today in Nature Photonics, scientists from Wellman Center for Photomedicine and Harvard Medical school have developed a “living laser” by using biological materials- human cell and jellyfish fluorescent protein. In order to get coherent beam of light from a lasing device, three things are required- a pump source (typically flash lamp, electric current or other laser source), a ‘gain media’ for amplifying the source (optical gain) and an ‘optical cavity’ for concentration and alignment of the laser beam. Typically, crystals, dyes, gas mixtures and even alcohol have been used as gain media to amplify the light. Pumping source produces population inversion in the gain media wherein majority of the atoms and molecules are in excited state. When a photon of appropriate wavelength interacts with such a system of atoms/molecules, stimulated emission occurs. In a very novel approach, researcher Malte Gather has used Green Fluorescent Protein (GFP) and inserted the protein in living human embryonic kidney cell. Bioluminiscent GFP was first isolated from jellyfish in 1962 which ultimately resulted in Noble prizes for it’s discoverers. The kidney cell-GFP combo (gain medium) was then kept in between an optical cavity made of mirrors kept 20 microns apart. The dimension of single cell gain media was also about the same. When researchers hit the cell with low energy pulses of blue light using a microscope, typical diffused ordinary fluorescence was observed. But after reaching a certain threshold of input energy (~0.9 nJ), the light output from the cell changed drastically and resulted in bright, directional and narrowband emission of green light, which are the characteristics of a laser beam. Certain regions of cell showed intense lasing action (as shown in picture above) which occurred at different but close range of wavelengths (~514-519 nm). Researchers also reported that even after prolonged lasing action, the cell was still alive. The lasing action lasted for few nanonseconds and was easily detectable. The cell was able to lase about 100 pulses at excitation pulse energy of 50 nJ after which photobleaching occurred and depleted the GFP. But an interesting aspect of GFP infused cell is that the cell is able to heal itself and replenish GFP with time.
Here is an output emission spectra of the laser filled with purified GFP solution when pumped using different wavelengths of light. As can be seen that the output spectra is independent of the pump wavelength. This spectra tells two things i) independence of excitation wavelength on the emission rules out any stimulated scattering process as an explanation for lasing action by GFP, ii) FWHM ( Full Width at Half Maximum) of about 12 nm signifies the presence of simultaneous oscillations of various longitudinal modes.
Next figure shows that replacing the GFP solution with GFP-transfused cell resulted in much narrow output spectra. At energy threshold of 0.9 nJ, single emission peak was observed at 516 nm (FWHM <0.04 nm). As the energy was increased, multiple emission peaks were observed which can be attributed to multiple longitudinal oscillation modes. The spectral spacing between these emission line was in the range of 5 nm.
Researchers speculate that the resulting light could be used to study various intercellular processes. Before producing output light, the light travels several times through the cell placed inside the optical cavity and the resulting lasing light should contain information regarding the intercellular processes. Another possible use could be to produce such lasing beams inside the body itself to kill certain cancerous cells .
Creators of living laser, Yun and Gather, have some broad and speculative ideas about how the technology might be used.
They suggest that biologists could turn cells of interest into lasers to study them. The light produced has a unique emission spectrum related to both the structure of the cell and the proteins inside it. “By analysing the pattern you can get some idea of what is happening inside the cell,” says Yun.
The researchers also suggest possible medical applications. Doctors today shine lasers into the body to gather images or to treat disease by attacking cells. Yun thinks that lasers could instead be generated or amplified inside the body, where they could penetrate the relevant tissues more deeply. [Nature News]
Image credit: 1) Malte Gather | Nature Photonics | Wired 2) From the supplement files of the article provided on Nature website 3) Snapshot of the plots as seen at Nature website
Here is an amazing picture of space shuttle endeavour parked at the International Space Station. The image was taken on May 23rd by ESA astronaut Paolo Nespoli while he was leaving the space station aboard on Russian spacecraft Soyuz. His spacecraft was at a distance of about 600 feet when this picture was taken. Endeavour helped in building up the station over the past decade and this was the last space trip of Endeavour. Truly an amazing image. By the way if you ever wondered how parking your vehicle in space would look like, now you got the idea! If you want more of this, here is a high quality video taken by Nespoli.
February 5, 2012 1906 John Carradine 1920 Frank Muir CBE 1946 Charlotte Rampling 1948 Barbara Hershey 1948 Lord Haden Guest 1948 Sven-Goran Eriksson 1952 Russell Grant 1962 Jennifer Jason Leigh 1966 Jose Maria Olazabal
Now just thinking of creative ways to use this new scientific tool I am learning. So, Science Is Beautiful-Season 2 starts from today with pictures from Purdue University after weekend snowfall.
