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Physics

Chandra X-Ray Observatory

December 24th, 2011

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Star CoRoT-2a Fries Nearby Planet

This graphic contains an image and illustration of a nearby star, named CoRoT-2a, which has a planet in close orbit around it. The separation between the star and planet is only about three percent of the distance between the Earth and the sun, causing some exotic effects not seen in our solar system.

The planet-hosting star is located in the center of the image. Data from NASA’s Chandra X-ray Observatory are shown in purple, along with optical and infrared data from the Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes, or PROMPT, and the Two Micron All Sky Survey, or 2MASS. CoRoT-2a is surrounded by a purple glow showing that it is an X-ray source.

This star is pummeling its companion planet — not visible in this image — with a barrage of X-rays 100,000 times more intense than the Earth receives from the sun. Data from Chandra suggest that high-energy radiation from CoRoT-2a is evaporating about five million tons of matter from the nearby planet every second, giving insight into the difficult survival path for some planets. The artist’s representation shows the material, in blue, being stripped off the planet.

The Chandra observations provide evidence that CoRoT-2a is a very active star, with bright X-ray emission produced by powerful, turbulent magnetic fields. This magnetic activity is represented by the prominences and eruptions on the surface of the star in the illustration.

Such strong activity is usually found in much younger stars and may be caused by the proximity of the planet. The planet may be speeding up the star’s rotation, causing its magnetic fields to remain active longer than expected. Support for this idea comes from observations of a likely companion star to CoRoT-2a that orbits at a distance about a thousand times greater than the distance between the Earth and the sun. This star is visible in the image as the faint, nearby star located below and to the right of CoRoT-2a. It is also shown as the bright background star in the illustration. This star is not detected in X-rays, perhaps because it does not have a close-in planet like CoRoT-2b to cause it to stay active.

The planet, CoRoT-2b, was discovered by the French Space Agency’s Convection, Rotation and planetary Transits, or CoRoT, satellite in 2008. It is located about 880 light years from Earth and has a mass about three times that of Jupiter.

Credits: Optical: NASA/NSF/IPAC-Caltech/UMass/2MASS, PROMPT; Wide field image: DSS; X-ray: NASA/CXC/Univ of Hamburg/S.Schröter et al; Illustration: CXC/M. Weiss

Physics

Electromagnetic Induction

July 24th, 2011

An easy way to create a magnetic field of changing intensity is to move a permanent magnet next to a wire or coil of wire. Remember: the magnetic field must increase or decrease in intensity perpendicular to the wire (so that the lines of flux “cut across” the conductor), or else no voltage will be induced:

emi

Physics

Discharge Lamps

July 17th, 2011
Neon Lamp

Neon Lamp

Sodium vapour Lamp

Sodium vapour Lamp

Colours For Different Gases

Colours For Different Gases

Inert Gases

Inert Gases

Physics

The Water Planet

April 24th, 2011

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Viewed from space, the most striking feature of our planet is the water. In both liquid and frozen form, it covers 75% of the Earth’s surface. It fills the sky with clouds. Water is practically everywhere on Earth, from inside the planet’s rocky crust to inside the cells of the human body. This detailed, photo-like view of Earth is based largely on observations from MODIS, the Moderate Resolution Imaging Spectroradiometer, on NASA’s Terra satellite. It is one of many images of our watery world featured in a new story examining water in all of its forms and functions.

Image Credit: NASA

Physics

തണ്ടര്‍ ബോള്‍ട്ട്

April 1st, 2011

thunderbolt

Physics

Giant Ring of Black Holes

February 16th, 2011

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Just in time for Valentine’s Day comes a new image of a ring — not of jewels — but of black holes. This composite image of Arp 147, a pair of interacting galaxies located about 430 million light years from Earth, shows X-rays from the NASA’s Chandra X-ray Observatory (pink) and optical data from the Hubble Space Telescope (red, green, blue) produced by the Space Telescope Science Institute, or STScI.

Arp 147 contains the remnant of a spiral galaxy (right) that collided with the elliptical galaxy on the left. This collision has produced an expanding wave of star formation that shows up as a blue ring containing in abundance of massive young stars. These stars race through their evolution in a few million years or less and explode as supernovas, leaving behind neutron stars and black holes.

A fraction of the neutron stars and black holes will have companion stars, and may become bright X-ray sources as they pull in matter from their companions. The nine X-ray sources scattered around the ring in Arp 147 are so bright that they must be black holes, with masses that are likely ten to twenty times that of the sun.

An X-ray source is also detected in the nucleus of the red galaxy on the left and may be powered by a poorly-fed supermassive black hole. This source is not obvious in the composite image but can easily be seen in the X-ray image. Other objects unrelated to Arp 147 are also visible: a foreground star in the lower left of the image and a background quasar as the pink source above and to the left of the red galaxy.

Infrared observations with NASA’s Spitzer Space Telescope and ultraviolet observations with NASA’s Galaxy Evolution Explorer (GALEX) have allowed estimates of the rate of star formation in the ring. These estimates, combined with the use of models for the evolution of binary stars have allowed the authors to conclude that the most intense star formation may have ended some 15 million years ago, in Earth’s time frame. 

These results were published in the October 1st, 2010 issue of The Astrophysical Journal. The authors were Saul Rappaport and Alan Levine from the Massachusetts Institute of Technology, David Pooley from Eureka Scientific and Benjamin Steinhorn, also from MIT.

Image Credit: X-ray: NASA/CXC/MIT/S .Rappaport et al., Optical: NASA/STScI

Physics

The length of day and night on the moon?

January 18th, 2011

phases-moon

Yes, there are day and night on the moon, but not the same as our planet. Instead of twenty-four hours, a moon-day is equal to 27.3 earth-days because the moon takes so much time to complete a rotation around its axis. What is more surprising is that the moon takes exactly the same amount of time to complete a circle around the earth too, i.e. 27.3 days. As a result we always see only one side of the moon. At the most 59% of the moon’s surface is visible from the earth. The rest 41% of the surface is never seen by us.
Furthermore, the moon only has a day and a night, and no evening! The reason: There is no atmosphere on the moon. Due to the absence of air the sun-rays do not scatter at all. Hence, where the sun-rays fall there is a dazzling light and the rest is extremely dark! As if sunshine and darkness are partitioned by drawing a line between them. In the same way without air the climate is also not temperate on the moon. The temperature in the light would be 102°C, whereas an inch away in the dark the mercury would drop down to freezing -157°C!

News

Why can’t we remember certain dreams?

January 11th, 2011

The question is only regarding memory. We remember some of our dreams. A dream is an experience of a special kind. It is something happening in the part of our brain which has to do with consciousness and experience, and the brains’ general power of memory applies to this as it does to other cases. But, of course, the brain in is in a peculiar state when we dream. The whole of it is not working, and so our recollection of dream is, as a rule, not really so good as that of our waking experiences.

The more clearly we remember a dream, the greater must have been the part of the brain machine that was working at the time we dreamed. On the other hand, there’s no doubt that we have many dreams which we do not remember at all when we wake, which were due to the working of only a very small part of the brain. We see from this that we can judge which dreams are the best kind to have, if we are to have any. The more definite a dream is, the more vivid it is and the better we remember it, the more awake our brain was when we dreamed, the less was the rest it was getting, the poorer and less valuable was our sleep. But when a dream is scarcely remembered, or not remembered at all, and when it is very faint and vague, then our brain was much less awake during the dream and our rest and sleep were so much the less injured

Biology

January 10th, 2011

Human_placenta

The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother’s blood supply Placentas are a defining characteristic of eutherian or “placental” mammals, but are also found in some snakes and lizards with varying levels of development up to mammalian levelsThe word placenta comes from the Latin for cake, mammals produce a choriovitelline placenta that, while connected to the uterine wall, provides nutrients mainly derived from the egg sac

Endocrine function

In humans, aside from serving as the conduit for oxygen and nutrients for fetus, placenta secretes hormone (secreted by syncytial layer/syncytiotrophoblast of chorionic villi)that is important during pregnancy.

Hormones:

Human Chorionic Gonadotropin (hCG). The first placental hormone produced is hCG, which can be found in maternal blood and urine as early as the first missed menstrual period (shortly after implantation has occurred) through about the 100th day of pregnancy. This is the hormone analyzed by pregnancy test; a false-negative result from a pregnancy test may be obtained before or after this period. Women’s blood serum will be completely negative for hCG by one to two weeks after birth. hCG testing is proof that all placental tissue is delivered. hCG is only present during pregnancy because it is secreted by the placenta, which of course is present only[8] during pregnancy. hCG also ensures that the corpus luteum continue to secrete progesterone and estrogen. Progesterone is very important during pregnancy because when its secretion decreases, endometrial lining will slough off and pregnancy will be lost. hCG suppresses the maternal immunologic response so that placenta is not rejected.

Human Placental Lactogen (hPL [Human Chorionic Somatomammotropin]). This hormone is lactogenic and growth-promoting properties. It promotes mammary gland growth in preparation for lactation in the mother. It also regulates maternal glucose, protein, fat levels so that this is always available to the fetus.

Estrogen. It is referred to as the “hormone of woman” because it influences the female appearance. It contributes to the woman’s mammary gland development in preparation for lactation and stimulates uterine growth to accommodate growing fetus.

Progesterone. This is referred to as the “hormone of mothers” because it is necessary to maintain endometrial lining of the uterus during pregnancy. This hormone prevents preterm labor by reducing myometrial contraction. This hormone is high during pregnancy

Physics

World’s Cheapest Laptop

December 30th, 2010

India has unveiled a prototype tablet touchscreen laptop, priced at 1,600 rupees (35 U.S. dollars) , which it hopes to roll out in the market

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India Develops World’s Cheapest Laptop commercially next year.

Indian Minister for Human Resource Development Kapil Sibal Friday unveiled the device, which also comes with a solar-power option, as part of a push to provide high-quality education to students across the country.

Jointly developed by IIT-Rajasthan and IIT-Kanpur, the cheapest computer in the world, weighs 400 grams, which has all the applications of a regular computer.

The laptop is equipped with touch-screen device and is also wi-fi enabled to access Internet. However, the motherboard is absent from the laptop but it can be handy for students. Interestingly, without hard disk it has 2GB memory. It can be connect0ed to external memory of 32 GB.

The laptop has 256 RAM with two watt power. It has an alternate solar battery support.

He further said that the laptop is easily portable and it can be connected to a keyboard using USB port. The minister said the cost of this tablet laptop expected to go down further as more innovations are introduced.

The laptop will be available for students under the National Mission on Education through ICT.