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{tab= Phoenix to extend its arm}
Phoenix to extend its arm...
Phoenix is about to extend its robotic arm to dredge the Martian surface. Water is likely to be present in frozen state below the soil. The arm can stretch upto 2.35 meters and can shovel the soil upto the depth of 0.5 meter, sufficient enough to reach the underneath icy layer. The Information from this subsurface portion will be used to explore the past history of Martian arctic. Phoenix will also look for evidence of habitable zone by analysing the soil for vital elements like carbon, nitrogen, phosphorus and hydrogen. Analysis will be carried out by instruments onboard the spacecraft. Phoenix will also study the effect of polar conditions on overall Martian climate in this 3 month campaign.
Polar soil and Polar landscape
[Credit: NASA/JPL]
Phoenix has landed in the northern polar region of Mars after a space travel of nearly nine and half months. It is the first spacecraft to land in the polar regions of Mars. It is also the first soft-landing of the spacecraft on the Martian surface without use of any airbags, since the landing of Viking in 1976. Not only the landing of the Phoenix was smooth, but deployment of the solar panels of the spacecraft was also successfully achieved. Phoenix will draw its electrical power from these solar panels. Signals confirming the smooth landing of Phoenix were sent to Earth stations through Space Odyssey, which is orbiting around Mars for last six years. Close-view photographs of the ground show that polar terrain of Mars is similar to the terrestrial arctic terrain.
Spacecraft Phoenix derives its name from mythical bird which had arisen from ashes. Spacecraft Phoenix has also been built from residuum. It uses instruments from earlier unsuccessful Mars Polar Lander mission of 1999. The spacecraft itself is the one which was to be used for Mars Surveyor 2001 Lander mission. Mission was cancelled for administrative reasons and the spacecraft was kept in solitude, since it was built in the year 2000.
{tab=Third eye of Jupiter}
Third eye of Jupiter...
The Great Red Spot is characteristic feature of Jupiter's 'surface'. It is one of the most ferocious storms in our solar system. Stormy winds in this area are flowing at a speed of more than 400 km/hr. Area covered by the storm is so huge that it can easily accommodate two earth-size planets. This Great Red Spot has attracted the attention of the astronomers since it was discovered about 350 years ago. Something else is now happening in the vicinity of this Great Red Spot. In the year 2006, one more oval-shaped red spot had formed near the Great Red Spot. This new red spot is smaller in size compared to Great Red Spot. And now, a third red spot which is much smaller in size has shown its presence in the west of these two red spots. This red spot is also oval in shape like its predecessors.
Red spots on Jupiter (newly formed spots are at left)
[Credit: University of California, Berkeley]
Both the newly formed red spots must be storms like Great Red Spot. Scientists are not sure about their formation. These storms should also be so powerful that material is being drawn from deep below the Jupiter's clouds. Youngest red spot was white in colour in the beginning. It turned red probably after being exposed to ultraviolet radiation from Sun. Fate of these red spots is not known. But from the motion, it appears that the youngest red spot will merge into Great Red Spot by the month of August.
In the year 2004, Phil Marcus from University of California (USA) had predicted that Jupiter would start undergoing severe global climatic changes from the year 2006 onwords. He had expected substantial changes of 8C to 10C in the temperature of Jupiter's atmosphere. Probably, the formation of the two new red spots is an indication of the turbulence created in the atmosphere due to these global changes in the Jovian climate.
{tab= 'Sought-after' Supernova}
'Sought-after' Supernova detected?
It was in the year 1604 that previous supernova was observed in our Milky Way Galaxy. This supernova is known after famous German astronomer-cum-mathematician Yohannes Kepler. No supernova has been observed in Milky Way Galaxy since then. According to today's astronomers, supernova explosion is now due to be observed. Nearly two decades back, astronomers had discovered remnants of a supernova near the centre of our Galaxy which is in the constellation of Sagittarius. And these remnants have turned out to be probably the remnants of the 'sought-after' supernova...! Computations show that this supernova could have been observed 150 years ago. But it is the dust near the centre of Galaxy that had obscured its view.
Location of supernova
[Credit: NASA]
Remnants of this supernova were discovered using Very Large Array radio telescope from New Mexico (U.S.) in the year 1985. They are identified as 'G1.9+0.3'. Expansion of these remnants was recently noticed by Chandra X-ray Observatory which is watching the sky from space. Rapid expansion of the shell of supernova was then confirmed by Very Large Array radio telescope. Observations showed that shell had expanded by as much as 15% during last 23 years. Back calculations showed that the age of these supernova remnants, what we see today, is not more than 150 years. The shell is found to be expanding at an enormous rate of about 12,000 km/sec, which is about 4% of the speed of light. These supernova remnants are located at less than 2° from the galactic centre and are about 28,000 light years away from us.
{tab=Greatest escape}
Greatest Escape!
Black hole is known to swallow everything that comes close to it. But there exists a black hole which itself is running away from its surroundings. This evading black hole is discovered by Stefanie Komossa and her colleagues from Max Planck Institute for Extraterrestrial Physics (Germany). When two galaxies collide, the supermassive black holes at their centres merge. But the newly formed black hole cannot continue to remain at its position, but is kicked away from the merging galaxies. That is what it has happened in this case. The 'compound' black hole, that has formed from a merger of two black holes, is moving away from the galaxies with an enormous speed of 2,650 kilometers per second (9,540,000 kilometers per hour). It is over 100 million times massive than our Sun and is ten billion light years away from us.
Escape of a black hole: Artist's concept
[Credit: MPE/HST]
This 'super kick' is a consequence of theory of General Relativity and astrophysicists have already predicted such an escape earlier. As the black holes merge, intense gravitational waves are generated. Since these waves propagate in one particular direction, the compound black hole experiences a recoil in opposite direction. This recoil is so strong that gravity of the merging galaxies cannot stop the movement of the black hole. These predictions of General Relativity have been validated by this discovery of escaping black hole. The discovery is based on ealier spectral studies carried out with Roentgen Satellite (ROSAT), Galaxy Evolution Explorer (GALEX) and Sloan Digital Sky Survey.
{tab= Magnetic Mercury }
Magnetic Mercury...
Although too feeble, Mercury has a magnetic field. It is less than 1% in strength compared to that of Earth. Terrestrial magnetic field is a consequence of iron-rich core of Earth. Mercurial magnetic field is also a consequence of its iron-rich core. Both the planets have outer core which is in molten condition and inner core which is solidified due to immense pressure on it. But there is a difference in the way in which the magnetic field of the two planets is generated. In the case of Earth, it is geodynamo effect wherein the field is generated through the movement of molten core itself. In the case of Mercury, where its large-size core is expected to contain sulphur in addition to iron, core properties are somewhat different.
Core of Mercury
[Credit: National Science Foundation]
Laboratory studies carried out by Jie Li and others from the University of Illinois (USA) have shown that iron crystals separate out from molten iron-sulphur mixture if subjected to very high pressure. Mercury is probably having similar conditions at its core. Iron flakes crystallise out in the outer molten iron-sulphur core due to very high pressure on the core. The iron crystals then move through the outer molten core and settle on inner solid core. According to Jie Li, it is this movement of solidified iron throgh the outer molten core that is responsible for imparting the weak magnetic field observed around Mercury. Whether these inferences are realistic or not will be clear only after NASA'a Messenger spacecraft visits Mercury in the year 2011.
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