Astronomers have used the ESO's (European Southern Observatory's) Very Large Telescope, along with a double natural "magnifying glass" known as the "Einstein Cross", to scrutinize the inner parts of the disc around a supermassive black hole 10 billion light years away.
The "Einstein Cross", a famous cosmic mirage, is a cross-shaped configuration consisting of four images of a single very distant source.
The multiple images are a result of gravitational lensing by a foreground galaxy, an effect that was predicted by Albert Einstein as a consequence of his theory of general relativity.
The light source in the Einstein Cross is a quasar approximately ten billion light-years away, whereas the foreground lensing galaxy is ten times closer.
The light from the quasar is bent in its path and magnified by the gravitational field of the lensing galaxy.
This magnification effect, known as "macrolensing", in which a galaxy plays the role of a cosmic magnifying glass or a natural telescope, proves very useful in astronomy as it allows us to observe distant objects that would otherwise be too faint to explore using currently available telescopes.
Monday, December 29, 2008
Astronomers discover Universe's hottest white dwarf
A team of German and American astronomers have discovered the hottest white dwarf in the Universe, using NASA's space-based Far-Ultraviolet Spectroscopic Explorer (FUSE).
Known as white dwarf KPD 0005+5106, it is among the hottest stars ever known with a temperature of 200,000 K at its surface.
It is so hot that its photosphere exhibits emission lines in the ultraviolet spectrum, a phenomenon that has never been seen before.
These emission features stem from extremely ionized calcium (nine-fold ionized, i.e., CaX), which is the highest ionization stage of a chemical element ever discovered in a photospheric stellar spectrum.
Stars of intermediate mass (1-8 solar masses) terminate their life as an Earth-sized white dwarf after the exhaustion of their nuclear fuel. During the transition from a nuclear-burning star to the white dwarf stage, the star becomes very hot.
Many such objects with surface temperatures around 100,000 Kelvin are known.
Since its discovery as a faint blue star in 1985, KPD 0005+5106 attracted much attention because optical spectra taken with ground-based telescopes suggested that this white dwarf is very hot.In addition, it belongs to a particular class of rare white dwarfs whose atmospheres are dominated by helium.
A detailed analysis of these spectra, combined with ultraviolet observations performed with the Hubble Space Telescope (HST), had led to the conclusion that KPD 0005+5106 has a temperature of 120,000 Kelvin, which made it the hottest member of its class.
Although theory predicted the existence of such hot white dwarfs, the star nevertheless represents a challenge to the concepts of stellar evolution because of its composition.
Known as white dwarf KPD 0005+5106, it is among the hottest stars ever known with a temperature of 200,000 K at its surface.
It is so hot that its photosphere exhibits emission lines in the ultraviolet spectrum, a phenomenon that has never been seen before.
These emission features stem from extremely ionized calcium (nine-fold ionized, i.e., CaX), which is the highest ionization stage of a chemical element ever discovered in a photospheric stellar spectrum.
Stars of intermediate mass (1-8 solar masses) terminate their life as an Earth-sized white dwarf after the exhaustion of their nuclear fuel. During the transition from a nuclear-burning star to the white dwarf stage, the star becomes very hot.
Many such objects with surface temperatures around 100,000 Kelvin are known.
Since its discovery as a faint blue star in 1985, KPD 0005+5106 attracted much attention because optical spectra taken with ground-based telescopes suggested that this white dwarf is very hot.In addition, it belongs to a particular class of rare white dwarfs whose atmospheres are dominated by helium.
A detailed analysis of these spectra, combined with ultraviolet observations performed with the Hubble Space Telescope (HST), had led to the conclusion that KPD 0005+5106 has a temperature of 120,000 Kelvin, which made it the hottest member of its class.
Although theory predicted the existence of such hot white dwarfs, the star nevertheless represents a challenge to the concepts of stellar evolution because of its composition.
Scientists identify new region of magnetosphere
A detailed analysis of the measurements of five different satellites has revealed the existence of the warm plasma cloak, a new region of the magnetosphere.
This region is the invisible shield of magnetic fields and electrically charged particles that surround and protect Earth from the onslaught of the solar wind.
The study was conducted by a team of scientists headed by Charles Chappell, research professor of physics and director of the Dyer Observatory at Vanderbilt University.
A "natural cycle of energization" that accelerates the low-energy ions that originate from Earth's atmosphere up to the higher energy levels characteristic of the different regions in the magnetosphere.
This brought the existence of the new region into focus.
The warm plasma cloak is a tenuous region that starts on the night side of the planet and wraps around the dayside but then gradually fades away on the afternoon side.
As a result, it only reaches about three-quarters of the way around the planet.
It is fed by low-energy charged particles that are lifted into space over Earth's poles, carried behind the Earth in its magnetic tail, but then jerked around 180 degrees by a kink in the magnetic fields that boosts the particles back toward Earth in a region called the plasma sheet.
This region is the invisible shield of magnetic fields and electrically charged particles that surround and protect Earth from the onslaught of the solar wind.
The study was conducted by a team of scientists headed by Charles Chappell, research professor of physics and director of the Dyer Observatory at Vanderbilt University.
A "natural cycle of energization" that accelerates the low-energy ions that originate from Earth's atmosphere up to the higher energy levels characteristic of the different regions in the magnetosphere.
This brought the existence of the new region into focus.
The warm plasma cloak is a tenuous region that starts on the night side of the planet and wraps around the dayside but then gradually fades away on the afternoon side.
As a result, it only reaches about three-quarters of the way around the planet.
It is fed by low-energy charged particles that are lifted into space over Earth's poles, carried behind the Earth in its magnetic tail, but then jerked around 180 degrees by a kink in the magnetic fields that boosts the particles back toward Earth in a region called the plasma sheet.
Solar car completes world trip
This is the first time in history that a solar-powered car has travelled all the way around the world without using a single drop of petrol.
Laser instrument of Chandrayaan-1 successfully turned on
The Lunar Laser Ranging Instrument (LLRI), one of the 11 payloads carried by the Chandrayaan-1 spacecraft, was successfully turned on when it was passing over the western part of Moon's visible hemisphere.
The LLRI sends pulses of infrared laser light towards a strip of lunar surface and detects the reflected portion of that light. With this, the instrument can very accurately measure the height of Moon's surface features.
The instrument will be continuously kept on and is taking 10 measurements per second on both day and night sides of the Moon.
It is also providing topographical details of both polar and equatorial regions of the Earth's satellite.
Detailed analysis of the data sent by the LLRI helps in understanding the internal structure of the Moon as well as the way that celestial body evolved.It may be recalled that earlier, three payloads of Chandrayaan-1 -- Terrain Mapping Camera (TMC), Radiation Dose Monitor (RADOM) and Moon Impact Probe (MIP) -- were successfully turned on.
The MIP, carrying the Indian tricolour, was released from the spacecraft on 14th November and 25 minutes later, successfully impacted the lunar surface as intended.
TMC took pictures of the Earth and Moon when the spacecraft was on its way to Moon.
The LLRI sends pulses of infrared laser light towards a strip of lunar surface and detects the reflected portion of that light. With this, the instrument can very accurately measure the height of Moon's surface features.
The instrument will be continuously kept on and is taking 10 measurements per second on both day and night sides of the Moon.
It is also providing topographical details of both polar and equatorial regions of the Earth's satellite.
Detailed analysis of the data sent by the LLRI helps in understanding the internal structure of the Moon as well as the way that celestial body evolved.It may be recalled that earlier, three payloads of Chandrayaan-1 -- Terrain Mapping Camera (TMC), Radiation Dose Monitor (RADOM) and Moon Impact Probe (MIP) -- were successfully turned on.
The MIP, carrying the Indian tricolour, was released from the spacecraft on 14th November and 25 minutes later, successfully impacted the lunar surface as intended.
TMC took pictures of the Earth and Moon when the spacecraft was on its way to Moon.
‘Prerna’ scheme inspiring many
The Jansankhya Sthirata Kosh (the National Population Stabilisation Fund) will focus on involving the civil society in ‘responsible parenthood strategy’, called ‘Prerna’.
Prerna is a monetary incentive strategy aimed at pushing up the age of marriage of girls and delay the birth of the first child in the interest of health of young mothers and infants, particularly among those living below the poverty line, where child marriage and early motherhood is highly prevalent.
The couple become eligible for monetary reward if the girl is married at the age of 19, has her first child after she is 21 years, and the gap between the first and the second child is 36 months. It is also important that the parents undergo sterilisation after the second child.
The first set of awards was given to 34 couples from various districts of Orissa.
Prerna is a monetary incentive strategy aimed at pushing up the age of marriage of girls and delay the birth of the first child in the interest of health of young mothers and infants, particularly among those living below the poverty line, where child marriage and early motherhood is highly prevalent.
The couple become eligible for monetary reward if the girl is married at the age of 19, has her first child after she is 21 years, and the gap between the first and the second child is 36 months. It is also important that the parents undergo sterilisation after the second child.
The first set of awards was given to 34 couples from various districts of Orissa.
Pakistan theatre group performs at Thrissur festival
Voices for peace and tolerance were heard loud and clear at the International Theatre Festival of Kerala (ITFK) when the 16-member Lahore-based Ajoka staged a play, ‘Bullah,’.
The play seemed to offer an olive branch, echoing voices of sanity and making a strong pitch for a return to reason.
The play seemed to offer an olive branch, echoing voices of sanity and making a strong pitch for a return to reason.
Now, ISRO scientists develop hydrogen fuel cells to power bus
India's space scientists have developed hydrogen fuel cells to power an automobile bus by leveraging their know-how of the homegrown cryogenic technology for rockets.
The two-year effort has yielded positive results and the scientists are now readying for the fuel cells to be fitted into a bus.
ISRO and Tata Motors entered into an MoU in 2006 to design and develop an automobile bus using hydrogen as a fuel through fuel cell route. Tatas are taking the responsibility for the locomotive part of it, and hydrogen handling system also.
First protomodel has been assembled. Results are good. May be next year, it should be on the road.
The two-year effort has yielded positive results and the scientists are now readying for the fuel cells to be fitted into a bus.
ISRO and Tata Motors entered into an MoU in 2006 to design and develop an automobile bus using hydrogen as a fuel through fuel cell route. Tatas are taking the responsibility for the locomotive part of it, and hydrogen handling system also.
First protomodel has been assembled. Results are good. May be next year, it should be on the road.
Russia launches 3 navigation satellites
Russia's space agency has successfully launched three satellites to enhance its equivalent of the U.S. Global Positioning System.
Three GLONASS-M satellites have been put into orbit by a Proton-M rocket that blasted off from the Baikonur launch pad in Kazakhstan.
The satellites launched will join Russia's Global Navigation Satellite System, or GLONASS.The system had 17 satellites before this launch. It's supposed to have 24 satellites available worldwide.
The government had promised to make GLONASS fully operational by the beginning of this year, but it was delayed by equipment flaws and other technical problems.
Three GLONASS-M satellites have been put into orbit by a Proton-M rocket that blasted off from the Baikonur launch pad in Kazakhstan.
The satellites launched will join Russia's Global Navigation Satellite System, or GLONASS.The system had 17 satellites before this launch. It's supposed to have 24 satellites available worldwide.
The government had promised to make GLONASS fully operational by the beginning of this year, but it was delayed by equipment flaws and other technical problems.
"E Nose" to sniff out harmful chemicals on International Space Station
NASA astronauts on space shuttle Endeavour's STS-126 mission will install an instrument known as "ENose" on the International Space Station (ISS) that can help protect crew members' health and safety by "smelling" dangerous chemicals in the air. The experimental ENose will monitor the space station's environment for harmful chemicals such as ammonia, mercury, methanol and formaldehyde.
The ENose, which will run continuously and autonomously, is the first instrument on the ISS that will detect and quantify chemical leaks or spills as they happen.
It fills the long-standing gap between onboard alarms and complex analytical instruments. Air-quality problems have occurred before on the International Space Station, space shuttle and Russian Space Station Mir."The ENose is a 'first-responder' that will alert crew members of possible contaminants in the air and also analyze and quantify targeted changes in the cabin environment.
The shoebox-sized ENose contains an array of 32 sensors that can identify and quantify several organic and inorganic chemicals, including organic solvents and marker chemicals that signal the start of electrical fires. The ENose sensors are polymer films that change their electrical conductivity in response to different chemicals.The pattern of the sensor array's response depends on the particular chemical types present in the air.The instrument can analyze volatile aerosols and vapors, help monitor cleanup of chemical spills or leaks, and enable more intensive chemical analysis by collecting raw data and streaming it to a computer at JPL's ENose laboratory.
The ENose, which will run continuously and autonomously, is the first instrument on the ISS that will detect and quantify chemical leaks or spills as they happen.
It fills the long-standing gap between onboard alarms and complex analytical instruments. Air-quality problems have occurred before on the International Space Station, space shuttle and Russian Space Station Mir."The ENose is a 'first-responder' that will alert crew members of possible contaminants in the air and also analyze and quantify targeted changes in the cabin environment.
The shoebox-sized ENose contains an array of 32 sensors that can identify and quantify several organic and inorganic chemicals, including organic solvents and marker chemicals that signal the start of electrical fires. The ENose sensors are polymer films that change their electrical conductivity in response to different chemicals.The pattern of the sensor array's response depends on the particular chemical types present in the air.The instrument can analyze volatile aerosols and vapors, help monitor cleanup of chemical spills or leaks, and enable more intensive chemical analysis by collecting raw data and streaming it to a computer at JPL's ENose laboratory.
Canada, EU sign historic deal to open skies
Canada and the 27-nation European Union concluded a landmark aviation agreement that throws open their markets to each other and lifts restrictions on airline ownership, number of flights, routes and fare prices.
The historic agreement, which may kick in early next year, will allow any airline from Europe to operate to any city in Canada and vice versa. There will no restriction on the number of flights, routes or fare rates.
The agreement is one up on the similar US-EU agreement which does not allow European airlines to take over any US airline.
The historic agreement, which may kick in early next year, will allow any airline from Europe to operate to any city in Canada and vice versa. There will no restriction on the number of flights, routes or fare rates.
The agreement is one up on the similar US-EU agreement which does not allow European airlines to take over any US airline.
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