SpaceInfo

A very rare alignment between two spiral galaxies has been captured by Hubble Space Telescope. In the alignment, the outer edge of a small, foreground galaxy is silhouetted in front of a large background galaxy. The dust tentacles are beyond the small galaxy’s disk of starlight. Such a dusty structure is very rare in a galaxy.

Since the presence of dust affects and dims the actual brightness of the galaxy, it becomes difficult to measure the true brightness. Because of such a dusty scene, astronomers face the problems in measurement of distance of the object from the Earth. 

The background galaxy is about 10 times larger than the foreground galaxy. It is about the size of the Milky Way and 780 million light-years away. Though the scientists have calculated the distance from the Earth, they still don’t have the distance between the two galaxies. The alignment is happening near to the galaxy NGC 253. Hubble’s Advanced Camera was surveying NGC 253 and it spotted the two galaxies in the background.

The results of the event have been submitted for publication in The Astronomical Journal.

NASA, a leading space agency in the world has selected a robotic mission for the Mars. It’s a $485 million project which will be launched in 2013. The mission is called Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft. It will provide the information about Mars’ atmosphere, potential habitability and climate history. 

Doug McCuistion, director of the Mars Exploration Program at NASA Headquarters in Washington said, “This mission will provide the first direct measurements ever taken to address key scientific questions about Mars’ evolution. The loss of Mars’ atmosphere has been an ongoing mystery and MAVEN will help us solve it.”

The Phoenix mission confirmed that the red planet once had the presence of liquid water on the surface which is only possible because the planet was having denser atmosphere in the past. But in time, most of the Martian atmosphere was lost due to dramatic climate change. Now MAVEN’s job is to provide accurate measurements about current atmospheric loss of the red planet which will open new doors about Mars’ history.

MAVEN spacecraft will reach to Mars in the fall of 2014. It will use its propulsion system to enter the elliptical orbit ranging from 90 to 3870 miles above the planet. The spacecraft will be having 8 scientific instruments for measurements during a whole Earth year (equivalent to half of Martian year).

NASA’s Mars Scout Program is designed to plan a series of small, low cost and principal investigator led mission to the Mars. The Phoenix Lander was the first one in the series. The design of the spacecraft will be based on designs from NASA’s Mars Reconnaissance Orbiter and Mars Odyssey missions.

The MAVEN mission will be managed by Goddard Space Centre. University of Colorado will provide the mission planning and the technology development during next year.

For the first time in India, the students of Sona College of Technology from Tamil Nadu have developed parts for the GSLV mission. They have developed two special brushless motors which plays an important role in the GSLV missions. Till date, India used to import these motors for missions.

Among these two motors, the first one is a 32 newton metre, 1000 rotations per minute quadruplex brushless DC torque motor and will be used in the rocket nozzle for controlling its directions. Another one is a 2 newton metre, 50 rotations per minute slot less brushless DC motor. This motor will be used for controlling the rotations of the panels in the satellite. Second motor will also be used in the scan mechanism of microwave analysis detection of rain and atmospheric structures for the Megha Tropiques Spacecraft, said Director of Sona Special Power Electronics and Electric Drives (SSPEED).

Students from Sona College of Technology were displayed the prototype of both the machines to the ISRO scientists at Vikram Sarabhai Space Centre (VSSC) and ISRO’s Inertial System Units (IISU) at Thiruvanthapuram. IISU needed ‘cog free’ motors for the enhancement of performance of precision scanning mechanisms in spacecraft. But SSPEED had met all the required parameters.

“This was a “unique” achievement by an institution. This would save precious foreign exchange and provide valuable technical know how,” said Prof. Kannan, who designed and developed an aerospace quality component for actual use in ISRO’s satellites and rockets.

A new transient X-Ray source had discovered by XMM-Newton on 9th October 2007. This new X-Ray source detected is a counterpart of a nova, V598 Pup. The data is collected from EPIC camera and compared with the archive data of ROSAT mission. ROSAT mission was launched in 1990 for 10 years lifetime and is an effective way to detect X-Ray transient sources.

The source discovered on 9th October 2007 has a designation XMMSL1 J070542.7-381442. The designation is assigned with the help of Slew Survey having XMMSL1 as the prefix and their J2000 sky co-ordinates. The constellation Puppis is situated south east of the constellation Canis Major – with the bright star Sirius – and is visible at all latitudes southward of about 40 degrees N. The source is 750 times brighter than the upper limit at that position from the ROSAT archive. As the source of X-Ray has been detected, the research team is now searching for an optical counterpart.

There are 3 candidate sources lie inside the Slew Error Circle are identified. One of the candidates is a 16mV star named USNO A2.0 0450-03360039. It is chosen as one of the candidates due to a series of spectra acquired with the wavelength range 350-1000 nm which exposed the characteristics of emission lines found in the spectra of novas having late post-outburst state. All these observations are performed with the Magellan Clay 6.5m telescope on 16th November 2007.

The archive of All Sky Automated Survey (ASAS) is the encyclopedia of the history of all stars. Drastic increment is detected in the in the light from its normal luminosity between 2nd to 5th June 2007. This increment has been identified USNO A2.0 0450-03360039 as a nova and obtained designation as V598 Pup by IAU. It’s first nova to be discovered with X-Ray emission. Detailed observations of V598 Pup were performed with XMM-Newton on 30th October 2007 and with Swift satellite of NASA on 21st November 2007.

All these observations showed the decrement of X-Ray flux between 9th to 30th October with a factor of 15 and another one with the factor of 5 from 30th October to 21st November. Luckily, XMM-Newton was covering this sky region in that specific time period and witnessed to this bright nova.

A team of astronomers from Hawaii University has weighed 70 galaxies with the use of the gravitational lensing phenomenon. The gravitational lens is a phenomenon which occurs on a scale of thousands of light years. The results obtained from the observations will help to find the answer to the quest of the relationship between mass (the amount of matter) and luminosity (brightness) in galaxies. Dr. Adam Bolton has just announced these results and will be published in the astrophysical journal of August and September.

The results have been achieved with the use of Einstein ring concept. The Einstein ring images obtained are upto 30 times brighter than the image obtained without gravitational lensing. This invention is the conclusion of the Sloan Lens ACS (SLACS) Survey. This survey is a part of major project called Sloan Digital Sky Survey, with the help of a dedicated 2.5-meter telescope in New Mexico. Data gained for the gravitational lensing is from the Sloan Digital Sky Survey. This project is used to calculate precise distances to nearly one million distant galaxies and quasars throughout one quarter of the sky. Astronomers took help of Hubble telescope to observe and measure details of Einstein ring images.

The other lens surveys apart from SLACS, lens galaxy masses have not been calculated so accurately. Adam Bolton said, “The SLACS collection of lenses is especially powerful for science. For each lens, we measured the apparent sizes of the Einstein rings on the sky using the Hubble images, and we measured the distances to the two galaxies of the aligned pair using Sloan data. By combining these measurements, we were able to deduce the mass of the nearer galaxy.” 

Dark matter is the most puzzling thing in the universe. but with the use of large number of gravitational lens, scientists can find the fraction of dark matter related with stars of galaxies ranging from average mass to high mass. Hence, the results from SLACS will help scientists to understand the dark matter.

The resurgent interest has been formed among the US astrobiologists to find the alien life forms. Last Sunday, on 20th July, the Washington Post reported that there has been a drastic boost in the field of astrobiology, a branch of astronomy which deals with the possible forms of life those might be exist on other planets. Scientists say that the boost in the research in the field of astrobiology is mainly because of the discovery of ice on Mars.

“Until several years ago, absolutely nobody thought this kind of life was possible, it hadn’t even made it into science fiction. Now it’s quite possible to imagine a microbe like that living deep beneath the surface of Mars,” said Lisa Pratt. She is a biogeologist from Indiana University and one of the scientists who study extremophiles (study of microbes found in very harsh Earth environments). Pratt and her colleagues have studied the bacteria found in the depths of South African gold mines. Lisa said that these bacteria have sustained only by the radioactive decay of nearby rocks.

Most of the scientists now believe that there is possibility of discovery of life within the icy layers of Martian surface. But Edward Weiler, a founder of astrobiology program of NASA, said that there are likely other life forms in the layers. He said, “We now know the number of stars in the universe is something like 1 followed by 23 zeros. Given that number, how arrogant to think ours is the only sun with a planet that supports life, and that it’s in the only solar system with intelligent life.”

The powerful robotic arm of Phoenix lander has successfully drilled into the frozen Martian soil. Two holes have been made on the surface by the motorized rasp of the lander’s robotic arm scoop. The holes are named as Snow White. The material gathered in the process was collected in the scoop and was analyzed by Robotic Arm Camera (RAC).

The above activity was important for the testing of rasping method of gathering icy sample. This method will be used in the near future in the oven of Phoenix’s Thermal and Evolved Gas Analyzer for the analysis of the samples. “This was a trial that went really well, while the putative ice sublimed out of the shavings over several hours, this shows us there will be a good chance ice will remain in a sample for delivery to Phoenix’s laboratory ovens.” said Richard Morris, a Phoenix science team member from NASA.

On Wednesday, July 23rd, the lander will get the instructions about continuing enlargement of Snow White trench and the detailed instructions for another rasp tests. After the instructions are assigned to lander, the RAC will again start to analyze the collected samples in the scoop.

A team leading by Raytheon is working to deliver a complete solution for Indian Space Research Organization (ISRO) and Airports Authority of India (AAI). ISRO is working on its new project on satellite based navigation for civil aviation across East and South Asia. The project is called Global Positioning Satellite-Aided Geosynchronous Augmented Navigation System (GAGAN) which will be most accurate, efficient and flexible air navigation system by India.

The comprehensive solution delivered by Raytheon will complete the final phase of GAGAN. Since the GAGAN design is based on the space based augmentation systems, the Raytheon will use all its experience obtained during the past in deployment of technology demonstration system phase of GAGAN.

“We look forward to continuing our collaborative relationship with ISRO and AAI during this critical phase of GAGAN and we are committed to a thorough transfer of knowledge of the GAGAN system to further enhance India’s leadership position in air navigation,” said Raytheon’s Vice President, Andy Zogg.

Team members for GAGAN project are Accord Software and Systems, Pvt. Ltd. of Bangalore, India; Elcome Technologies, Pvt. Ltd. of New Delhi, India; and Naverus Inc., of Kent, Washington. Accord Software and Systems will look after of the optimization of GPS based user receiver prototype development for equatorial region. Elcome Technologies will take care of logistical and on-site support. And Naverus will control navigation route design, procedure flight validation and other related services.

The GAGAN project will set a milestone in Indian Space history and in South Asia.

NASA is planning a new mission which could possibly discover the space-time curvature around a black hole. In today’s date, none of the current missions have the perfect technology to execute this type of mission. Since magnetic fields are invisible, even the magnetic field imaging technique won’t be proved that much useful for this mission.

The mission is called Gravity and Extreme Magnetism (GEMS) and it will look for the structure and effects of complex magnetic fields around magnetars, dead stars etc. These types of objects have a very strong and mysterious magnetic field around them (approx. billion to trillion times stronger than Earth). For this purpose, GEMS will measure the polarization of X-Ray emission and will illustrate a new picture of these violent and disturbing areas. X-Ray emission will be used for this mission because X-Ray has vibrant electric fields which can polarize (means it can vibrate in a single direction) under some special situations. 

In GEMS, a chamber filled with a gas will be used. When this gas will encounter with X-Ray, it releases a cloud of electron. This electron cloud will be measured by an instrument to find direction of X-Ray’s electric field.

GEMS Principal Investigator Dr. Jean Swank said, “The extreme environments around black holes, magnetars, and the shocks from exploding stars called supernovae all produce X-rays. GEMS will be the first mission designed just to measure the polarization of these X-rays, which will enable us to explore these exotic places in an unprecedented way.” He is also working for NASA’s Goddard Space Flight Center. GEMS mission is a part of NASA’s explorer program and it will be developed in the spring of 2009.

GEMS could reveal many mysteries related to the strong magnetic and gravitational fields. Some of the quests are as follows:

• What happens in the strong magnetic fields of pulsars and magnetars?
• What is the effect of a black hole on surrounding space-time and the matter caught up within its strong gravitational field?
• How the shocks of supernova remnants accelerate the cosmic rays?

The project is a joint venture of Goddard Space Center, Orbital Sciences Corporation, ATK Space, Ames Research Center, University of Iowa and MIT.

Black hole is an area in space where, due to the very powerful gravitational field; nothing, not even a single photon can escape. It appears to be like a hole made in the universe, therefore it is called the black hole.  We can not see a black hole like other objects in the universe. A black hole can be detected till a certain limit called event horizon (it is also called as Schwarzschild radius). But despite their interior being invisible, a black hole may show its presence through the interaction with the matter surrounding it. One can observe gas falling into the black hole from a nearby star. The radiation that black hole emits is because of the gas which is heated up due to strong gravitational force of the black hole. Such observations have confirmed that black holes exist in the universe.

The idea of an object having very strong gravity like black holes was first suggested by a British astronomer, John Mitchell in 1783. Later, in 1795, a French physicist named Pierre-Simon Laplace came to the same conclusion in his book Mechanic Celeste. But the perfect mathematical and physical picture of Black holes has brought forward by a German physicist Einstein in his General relativity theory in 1916. In astronomy, the term ‘Black Hole’ was first used by John Wheeler in 1967. But in history, it was used by British for an historical event happened in 18th century named ‘Black Hole of Calcutta’ in India.

Generally, the phenomenon of black hole can be easily explained with the basic concept of escape velocity (it is the minimum velocity required to escape from gravity field of any celestial body). This concept was first used by Sir Isaac Newton. With the help of Newton’s law of Gravity, it can be proved that the escape velocity of sufficiently dense object would be equal to the speed of light.

Relativity theory states that nothing can exceed the speed of light. Theory of relativity bound two independent concepts of Newtonian mechanics (Space and Time) in one single concept called ‘Space-time’. The main conclusion of Relativity was no object can move freely in the space-time and it also can not change its position faster than the speed of light. In General Theory of Relativity in 1916, Einstein concluded that mass deforms the structure and the shape of surrounding space-time. Overall, objects tend to move toward masses, which phenomena, we feel as Gravity. As the object goes close to the mass, the effect of gravity gets stronger. This is the reason why we feel stronger gravity on surface of Earth as compared to any astronaut revolving around the Earth with his spacecraft. As the mass increases, the gravitational effect becomes stronger and stronger. And at specific point, the gravity becomes so strong that all possible paths lead the object to the center of the mass. This is what exactly happens when an object reaches to the Schwarzschild radius in case of a black hole. This is why nothing can escape from a black hole because you cannot exceed the speed of light.

As black holes are unique type of objects in the universe, it has got some unique features. These features are as follows:

Event Horizon:

It is one of the most important features of black hole. Event horizon (also called as Schwarzschild radius) is defined as a surface in space-time from where there is no path to return. Everything inside the event horizon is always invisible for any outside observer. The gravity inside and outside the event horizon behaves in different manner. Gravitational field outside event horizon behaves like the field produced by any other celestial object of same mass. But once the object crosses the event horizon, the gravity becomes so stronger that all the pulls by the gravity lead the object towards singularity.

Singularity:

Second unique feature of black hole is singularity. According to general relativity, it is a region within the black hole where the density and gravitational pull is infinite. So it curves the space-time to maximum extent. The singularity within a non-rotating black hole and a rotating black hole is different. In a non rotating black hole, it is just a central point with zero length, width and height. But in a rotating ones, it is ring shaped lying in the plane of rotation. In general relativity, singularity indicates the breakdown of theory. In the case of black holes, all components of an object (including atoms and sub-atomic particles) are torn apart from each other till the level of fundamental particles before striking the singularity. Since singularity is a very small region (almost like a small point), quantum mechanical effects along with gravity becomes vital at this point. Unfortunately, till date we don’t have a theory which will combine the quantum mechanics and theory of gravity (general relativity) for explanation of such features like singularity. This is why at the singularity, all the rules of relativity collapse and we need a new theory called quantum gravity to understand the behavior of object at singularity.

Photon Sphere:

Photon sphere is defined as the spherical boundary region of zero thickness in which photons moving tangential to sphere will be trapped in a circular orbit. The orbits of photon sphere are very unstable. In the case of light, it can escape from inside the photon sphere but once it crosses the photon sphere and goes into the inbound trajectory, it will be trapped by the black hole and will not return back. Photon spheres can also be seen in neutron stars.

Ergosphere:

Ergosphere is a region in the surroundings of a rotating black hole where no object can stand still. This process, called as frame dragging, in which rotating mass will tend to slight drag along the space-time immediately surrounding space-time. As a result of this, any object near to the rotating mass will also start moving in the direction of rotation. In case of black hole, this effect is so strong at the event horizon that the object has to move faster than the speed of light in the opposite direction to just stand still. According to the Penrose process, objects can still fly out of the ergosphere by using some of the black hole’s rotational energy. This would be resulted in slowing down black hole’s rotation and eventually stops.

Hawking Radiation:

In 1974, British astronomer Stephen hawking proved that a black hole can emit small amount of thermal radiation. He got this result with the use of quantum field theory. This showed that a black hole can emit particles in a perfect black body spectrum. This radiation is now known as Hawking radiation. But the emission of hawking radiation is so small (probably several nanokelvin) which is even much less than the temperature of cosmic microwave background (2.7 K).

Since a black hole has only three independent properties (mass, charge and angular momentum), any 2 black holes having same values for these properties are totally indistinguishable. Black holes are of many types and in variety of sizes. Karl Schwarzschild black holes are simplest possible black holes. This type of black holes doesn’t have charge or angular momentum but mass. Extremal black holes have the minimum possible mass that can be compatible with the charge and the angular momentum. In general, black holes can be classified with respect to their masses. Though the size of black hole is measured by the event horizon radius, there is a simple relation (T = 3 M/M0 where T is Schwarzschild radius, M is mass of black hole and M0 is mass of Sun) between the size and mass independent of rotation of object. Like various types of black holes mentioned above, they can be found in various different sizes. As far as the size is concerned, black holes can be classified into the following categories:

Supermassive Black Holes: 

Supermassive black holes exist in the center of most of the galaxies. These black holes have thousands to billions Solar masses and largest in their sizes. These black holes are mainly responsible for active galactic nuclei. These black holes are probably formed by the accretion of stars and gas onto them. The largest supermassive black hole which’s been found until today weighs about 18 billion solar masses.

Intermediate mass black holes: 

These black holes have sizes in hundreds of solar masses. There is no sufficient evidence to prove that this type of black holes exists. Physics don’t know the accurate mechanism to form intermediate black holes but it is believed that it can be formed in the dense stellar cores of globular clusters or galaxies.

Stellar mass black hole:

Stellar mass black holes have masses ranging from 1-3 solar masses to 15-20 solar masses. They are created by collapsing of individual stars or by the coalescence of binary neutron stars. Stars having masses approx. 100 times of the Sun, may become a red Giant or may follow the path to neutron stars and black holes. 

Micro black holes:

Micro black holes have masses much smaller than a star. There is no known mechanism for the formation of these types of black holes, but it is believed that in the early stages of universe, some conditions have produced them. Because of the size, quantum mechanics play an important role here. Hawking radiation states that such black hole evaporates in gamma radiation. GLAST satellite is launched in June 2008 for the search of such radiations.

Though black holes can not be seen by normal telescopes, there are some techniques to find the existence of black holes. Some of the techniques are as follows:

Radiation Emissions:

In most of the cases, steady or irregular EM, X-ray and Gamma radiation is not sufficient to prove that a black hole exists there. But the absence of irregular emission around an ultra-dense, massive object indicates that there is a fair chance of finding the black hole in that region. An intense one time gamma ray burst indicates birth of the black hole. Scientists can say this because Gamma ray bursts (also called as GRBs) can caused either by a collision between a neutron star and a black hole or by the gravitational collapse of a giant star. Yet GRB is not a complete proof for the existence of black hole. Since quasars are the most luminous objects in the universe irrespective of their distances. It is believed that quasars could be the accretion disks of supermassive black holes.

Accretion Disks and Gas Jets:

Like GRBs, most of the accretion disks and gas jets are not a clear proof of the existence of black hole. But an extremely dense accretion disk and gas jets can be a good evidence for a supermassive black hole because the requirement of large mass for these phenomena can be found in a black hole.

Gravitational Lensing:

In gravitational lensing, a source behind the massive dense object such as a black hole (acts as a lens) may appear as multiple images of a single object to the observer. In this phenomenon, mass warps space-time to create strong gravitational field and causes bending of light. Therefore the possibility of detecting a black hole is much obvious here.