Universe

The Universe is the collection of all that exists. It includes particles, energy, galaxies, solar system, stars and every others matter that interconnects each other. There are many theories proposed by various scientists which states the origin of universe. The prevailing scientific theory called "Big Bang" is an acceptable one.

What is Big-Bang Theory? 

The Big Bang Theory is the persisting cosmological approach which explains the origin and developments of the Universe. According to this theory, the universe was an utmost hot and dense sphererical ball which expanded rapidly. This expansion caused the Universe to cool again and again till the present state reached. Scientists suggest that the Big Bang occurred approximately 13.75 billion years ago which is predicted by various measurements. so it is reasonable to say this Universe is 13.75 billion years old. After the expansion from the single mass, the particles get converted into sub-atomic particles like proton, neutron and electrons. The big bang theory is a well acceptable one.

                                                 


How the first atom was formed?

The proton and neutron combines to form the first atomic nuclei only after a few minutes after the Big-Bang. But it took thousands of years for electron to combine with the atomic nuclei to form an electrically neutral atom. Thus the first atom formed is hydrogen.




THE VAN ALLEN BELTS - Radiation Belt around Earth

The Van Allen Belts surround Earth and contain killer electrons, plasma waves and electrical currents that disrupt the electronics on satellites. They are named after James Van Allen, who led the team that discovered them in 1958, during the flight of the first American satellite. The Explorer 1 had on board a Geiger-Müller tube to detect cosmic rays; readings periodically went off the top of the counter’s scale. Follow-up missions, including that of Explorer 3, showed that the space around Earth contained electrons, protons, and energy created by interactions between Earth's magnetosphere, the solar wind, and cosmic rays arriving from beyond the solar system.

The image is an artist’s interpretation of the radiation belts (in green); they are doughnut-shaped regions that are full of high energy particles. The blue and red lines represent the north and south polarity of Earth’s magnetic field. The inner belt is composed of protons and electrons, and can reach down as low as 1,000 kilometres in altitude. The outer belt, which consists mainly of energetic electrons, can reach as high as 60,000 kilometres above Earth’s surface. Both rings go as far as 65 degrees north and south latitude.

The Radiation Belt Storm Probes (RBSP), launched by NASA August 30 2012, will fly in separate orbits across both the inner and outer Van Allen Belts. The mission started near the height of the Sun’s 11-year cycle (aka solar maximum). The activity on the sun affects the behaviour of the radiation belts; solar storms can swell the belts with particles and energy which in turn accelerate electrons and create electrical currents. The RBSP will examine these accelerated electrons (aka ‘killer electrons’) as well as the electrical and magnetic fields, particles and plasma waves. The goal is to improve the prediction of space weather.



What is a Nebula? 

A nebula is an interstellar cloud in outer space that is made up of dust, hydrogen and helium gas, and plasma. It is formed when portions of the interstellar medium collapse and clump together due to the gravitational attraction of the particles that comprise them.

A Sword Shaped Nebula

This nebula, a mass of dust and gas, resides in the constellation Orion. To the naked eye it appears as the brightest ‘star' in the hunter’s sword. This image was released in 2006 and is a combination of visible and ultraviolet light from the Hubble telescope, as well as infrared data from the Spitzer Space Telescope.
The image, a composite, shows hundreds of young stars. The stars emit ultraviolet light as well as stellar wind, which are streams of charged particles that shape the cloud.



Cat's Paw Shaped Nebula

This nebula, also known as NGC 633 or the Bear Claw Nebula, lies near the centre of the Milky Way galaxy. It was first recorded by British astronomer John Herschel in 1837 during his stay in South Africa, using one of the largest telescopes in the world at the time.

The Nebula is 5,500 light years distant in the direction of the constellation Scorpius (the Scorpion). The gas cloud is about 50 light years across; it appears red because its blue and green light are scattered and absorbed more efficiently by material between the nebula and the Earth. The red light comes mainly from an abundance of ionized hydrogen atoms.

NGC 6334 is one of the most active nurseries of massive stars in our galaxy; the nebula hides new blue stars that are each nearly 10 times the mass of our Sun and only a few million years old. There are also many new ‘baby’ stars, deep within the dust. The Nebula could contain several tens of thousands of stars.

This image of the Cat’s Paw Nebula was created from images taken with the Wide Field Imager (WFI) instrument at the 2.2-metre MPG/ESO telescope at the La Silla Observatory in Chile. The images are combined and taken through blue, green and red filters, as well as a special filter designed to let through the light of glowing hydrogen.

TARANTULA NEBULA

The Tarantula Nebula is found near the star cluster NGC 2074, and is located within the Large Magellanic Cloud (LMC); one of our closest galaxies. It is also known as 30 Doradus or NGC 2070. It is named Tarantula as the arrangement of its bright patches somewhat resemble the legs of a tarantula. It is nearly 1,000 light years across, and has a high concentration of massive stars, referred to as super star clusters.

The image is based on data acquired with the 1.5 m Danish telescope at the ESO La Silla Observatory in Chile. It was shot through three filters (B: 80 s, V: 60 s, R: 50 s)The Tarantula Nebula is found near the star cluster NGC 2074, and is located within the Large Magellanic Cloud (LMC); one of our closest galaxies. It is also known as 30 Doradus or NGC 2070. It is named Tarantula as the arrangement of its bright patches somewhat resemble the legs of a tarantula. It is nearly 1,000 light years across, and has a high concentration of massive stars, referred to as super star clusters.

The image is based on data acquired with the 1.5 m Danish telescope at the ESO La Silla Observatory in Chile. It was shot through three filters (B: 80 s, V: 60 s, R: 50 s)



Sombrero Galaxy

This ring is part of the Sombrero Galaxy, also known as M104; one of the largest galaxies in the nearby Virgo Cluster of Galaxies. The galaxy spans about 50,000 light years across and is 28 million light years away. This image is in infrared light; in this light the dark band of dust that obscures the mid-section of the Galaxy glows brightly.

This image, digitally sharpened, was recorded by the orbiting Spitzer Space Telescope, superposed in false-colour on an existing image taken by NASA's Hubble Space Telescope in optical light.

Three Nebulae in a Narrow Band

These nebulae get their beautiful appearance from narrow band filters and a false-color palette. The three nebulae are stellar nurseries about 5,000 light-years distant, toward the nebula rich constellation Sagittarius. Charles Messier catalogued M8, above and right of centre and M20 at the left, in the 18th century. The third nebula is NGC 6559, at bottom right. M8 is also known as the Lagoon Nebula and is over 100 light years across; M20 is also known as the Trifid.

The image is a composite; narrow emission lines from sulphur, hydrogen, and oxygen atoms recorded through the filters are mapped into broader red, green, and blue colours respectively.

Exo-planets discovered by Kepler Telescope

Till now, 41 new transiting exoplanets have been discovered by NASA's Kepler space telescope in twenty different star systems. The studies (currently in peer review) could increase the number of exoplanets discovered by the Kepler Telescope by more than fifty per cent. 

Image caption: The diagram shows the newly submitted transiting planets in green along with the unconfirmed planet candidates in the same system in violet. The systems are ordered horizontally by increasing Kepler number and KOI designation and vertically by orbital period.

Helix Shaped Nebula

While this may look like a green version of the eye of Sauron, this Spitzer Space Telescope image shows infrared radiation from the Helix Nebula (NGC 7293). The nebula is 700 light years away, within the constellation Aquarius. The dust and gas gathered around the central white dwarf is two light years in diameter. 

The nebula is considered an excellent example of a planetary nebula in the final stages in the evolution of a sun-like star. The bright infrared glow surrounding the central star is most likely the result of a dust debris disk, which could have been generated by collisions with objects similar to our solar system’s Kuiper Belt or cometary Oort cloud, as the nebular material would have been ejected from the star thousands of years ago. Our own Sun will similarly decay in 5 billion years time.

Carina Nebula

This is the Carina Nebula, between 6,500 and 10,000 light years away from Earth in a constellation of the same name. This single pillar of gas and dust measures three light years in height; the red and purple hues of the nebula come from hot hydrogen gas interacting with ultraviolet radiation from the nebula's massive young stars that are buried within it.



Water - The most abundant compound in the Universe

Water is the most abundant compound in the universe; its composition consists of the 1st and 3rd most abundant elements, hydrogen and oxygen (helium is the 2nd most abundant element). Water in liquid form is common on Earth, but on other planetary bodies in the Solar System it is usually present as vapour or ice. 

After the Solar System formed, most of the water was locked up as ice in the surface or interiors of the farthest planetary bodies. Earth actually has little water, comparatively, and what it does have is mostly on the surface. 

Liquid water is also present as deep oceans on Europa and Titan, satellites of Jupiter and Saturn. The amount of liquid water on Mars and in Enceladus, a satellite of Saturn, could well be large. 

This image is a comparison of the liquid water volume of Earth, Europa, and Titan to scale. Europa is estimated to have over two times and Titan nearly eleven times more liquid water than Earth has as subsurface oceans. Only liquid water is considered in these estimates though water ice is present in considerable amounts on Europa and Titan. The image assumes a mean ocean depth of 4 km, 100 km, and 200 km for Earth, Europa, and Titan, respectively.

   

Exo-Planets develop into Planetary formation: 

A team of astrophysicists led by EXOEarths researcher Dr Vardan Adibekyan of the Centro de Astrofísica da Universidade do Porto, Portugal have found that metals like magnesium might play a significant role in the formation of low mass planets.

The team used the European Southern Observatory’s High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph to observe and analyse the high-resolution spectra of 1111 Sun-like stars. Of these, 109 are known to have high mass Jupiter-like planets, while 2 have Neptune-like planets.

Refractory Alpha Elements like magnesium, silicon or titanium make up the bulk of the mass of the terrestrial planets (Mercury, Venus, Earth and Mars) and a fraction of the giant planets and their moons. Researchers therefore focused especially on studying the abundance of these elements. The results show that the ratio of these elements, compared with the amount of iron, is consistently higher in stars with planets; magnesium shows the greatest discrepancy. The results may provide constraints for the models of planet formation, particularly planets with low mass.

Previously, the theories around planet formation suggested that planets were created through the clumping together of smaller particles of heavy elements, into larger bodies. These new results show that planets need a minimum amount of ‘metals’ to be formed; the formation of planets is dependent on the dust content of the cloud where the star and planetary system formed.



Silver and Gold are created by Stellar Explosions

Heidelberg scientist Dr. Camilla Hansen, working with scientists in Germany, Japan and Sweden, has shown that silver can only have materialised during the explosion of clearly defined types of star, different from the type of stars that produce gold when they explode. Evidence for this came from the measurement of various high-mass stars; by continuing with these kinds of measurements the components of all matter can be reconstructed.

Lightweight elements like hydrogen, helium and lithium were produced a few minutes after the Big Bang. All of the heavier elements were created later within the interior of stars or during star explosions; each new generation of stars increased the enrichment of the universe with chemical elements. The types of elements produced by a star in its lifetime depend on its mass. Stars about 10 times the size of our Sun explode as supernovae at the end of their lives, creating elements that are at times heavier than iron, that are then released by the explosion. Silver and gold can also be produced this way, depending on the original mass of the star.

When stars of the same mass explode, the ratio of elements created and ejected into space is identical. Dr Hansen and her colleagues’ research showed that the amount of silver in the stars measured is independent of the amounts of heavier elements like gold; silver takes place in a different fusion process than gold. Silver cannot have originated together with gold; the two elements must have originated from stars of different masses.



The Farthest Spiral Galaxy Ever Seen

At the edge of the observable universe, where most galaxies appear as blobs, lies BX442. It is found within the constellation Pegasus and has a redshift of 2.18; meaning it is 10.7 billion light-years from Earth and therefore existed just 3 billion years after the big bang.

Astronomer David Law and his team at the University of Toronto, St. George, in Canada used the Hubble Space Telescope to examine 306 distant galaxies. They spied a galaxy with three spiral arms, and confirmed the distance of the galaxy with subsequent observations using the Keck II telescope in Hawaii. The Doppler shifts from different parts of the galaxy’s disk show that it spins as fast as the Milky Way does. The galaxy is 50,000 light years across and though half the size of the Milky Way, it harbours more gas and spawns more stars. 

In the distant past, spiral galaxies were rare, as stars and gas clouds moved fast relative to each other which suppressed spiral structure and also caused more galactic collisions. Other galaxies from such early epochs appear clumpy and irregular. Almost two thirds of today’s bright galaxies are spirals. BX442’s spiral nature may be due to the small companion it has, stirring up the spiral structure, though it could be down to the large amount of gas in the galaxy.

In the time it has taken for the light of this galaxy to travel to Earth, it may already have collided with another galaxy, tearing apart the spirals and leaving the galaxy as an ellipsoidal shape.

The image shows an artist’s conception of the galaxy to the right; the image at left is of a companion galaxy whose gravity may have caused the spiral structure.



The Ant Shaped Nebula 

The Ant Nebula, aka Mz3, is a young bipolar planetary nebula in the constellation Norma. It is 8,000 light years away from Earth and it has a magnitude of 13.8. It was discovered by Donald Howard Menzel in 1922. The nebula is composed of a bright core and four high-velocity outflows which have been variously named as lobes, columns, rays, and chakram. The gas being ejected travels at 1000-kilometres per second and the structure is one light year long.

So why is this nebula an odd shape? There are a couple of possibilities.

1. One is that the central star of Mz3 has a companion orbiting closely that is exerting strong gravitational forces, shaping the out flowing gas. 
2. The second possibility is that the strong magnetic fields are being wound into complex shapes by the spin of the dying star. 

No other planetary nebula observed by Hubble closely resembles Mz3. M2-9 comes close, but M2-9 has prominent hydrogen emission lines in the near infra-red whereas Mz3 has no trace of molecular hydrogen emission.



Life May Exist on Titan

Saturn’s sixth and largest moon Titan has an average surface temperature of 94.2611Kelvin (-178.889°C or -290°F). Nitrogen comprises 98.4% of the atmosphere. Water is perpetually frozen; it can almost be considered a mineral. The seas of Titan are made up of hydrocarbons like methane, ethane, and some propane. The land masses are composed of frozen water and ammonia, which also exist in liquid states below Titan’s crust, much like silica and iron exist in liquid form below Earth’s crust.

Titan may still contain many of the components for life. Scientists have known for thirty years that complex carbon compounds called tholins exist on comets and in the atmosphere of the outer planets. In theory tholins could interact with water in a process called hydrolysis to produce complex molecules similar to those found on the early Earth; these compounds are called prebiotic. Titan is thought to be made mainly of ice; some of this ice may melt during meteor impacts or underground processes, producing ice volcanoes that eject lava made of ammonia mixed with water. Tholins could potentially react with this liquid water exposed by meteor impacts or ice volcanoes and produce probiotic organic molecules before the water freezes. Catherine Neish, a graduate student working on her doctorate in planetary science at the University of Arizona, showed that over a period of days, compounds similar to tholins can be hydrolysed at near-freezing temperatures. Liquid water exposed on Titan is believed to persist for hundreds to thousands of years.

Another study used data from NASA’s Cassini spacecraft. The craft detected large molecules at altitudes of some 965 km above Titan’s surface; but these molecules remained unidentified because of limitations of the craft’s instruments. Sarah Hörst, a graduate student in planetary science at the University of Arizona, led the research team that replicated the atmosphere of Titan in a large chamber at the temperatures present in the moon’s upper atmosphere. They used radio energy at a power level comparable to a moderately bright light bulb to simulate the sun’s ultraviolet light. UV light breaks up molecules like molecular nitrogen or carbon monoxide in Titan’s atmosphere, which leaves the individual atoms to choose different partners with which to form new molecules. The tiny aerosol particles produced by the experiment were run through a mass spectrometer, which is used to show the chemical formulae that make up the molecules within the aerosols. Hörst then ran these formulae past a roster of molecules known to be biologically important for life on Earth. She got 18 hits; 4 were nucleotides whose combinations form an organism’s genetic information encoded in DNA. It seemed it was more important for some form of oxygen to be present in the ingredients than it was for water to be present.

Billions of years ago Earth’s upper atmosphere may also have been the source for these "prebiotic" molecules, amino acids and the so-called nucleotide bases that make up DNA. Oxygen in early Earth history would have been in the form of carbon dioxide and carbon monoxide from volcanic activity, as well as from water released by volcanism and meteor and comet impacts. The oxygen on Titan seems to be coming from Enceladus, another moon of Saturn that is home to icy geysers that eject ice into space near its south pole. The water molecules ejected from Enceladus’ geysers can be carried great distances through Saturn’s system; some oxygen bearing minerals from this find their way to Titan.



The Constellation Cygnus

This image is a mosaic, showing clouds of colourful gas and dark lanes of dust. The light from the gas and dust is too faint for the human eye to see; long exposure times and special filters were used.

Cygnus is a northern constellation which lies on the plane of the Milky Way; the name is the Latin word for swan. It was first catalogued by the 2nd century astronomer Ptolemy; it is one of the 88 modern constellations. The constellation contains the Northern Cross, Cygnus X-1, the stars Deneb and Albireo, the Fireworks Galaxy, the Pelican Nebula, the North American Nebula, the Crescent Nebula, and the Veil Nebula.

Cygnus is the 16th largest constellation in the night sky, and occupies an area of 804 square degrees. It is in the fourth quadrant of the northern hemisphere (NQ4) and can be seen at latitudes between +90° and -40°.



Planetary Nebula 

This is a composite colour Hubble image of NGC 6751, a planetary nebula with complex features. It is 6,500 light years away in the constellation Aquila. The diameter of the nebula is around 0.8 light years (600 times the size of our solar system).

The colours represent the relative temperatures of the gas; blue, orange and red indicate the hottest to coolest gas. The streamer-like features of the nebula were created by winds and radiation from the central star, which at 140,000°C is rather hot.

The name planetary nebula is something of a misnomer. Planetary nebulae are shells of gas ejected by Sun-like stars nearing the ends of their lives. This gas ejection exposes the hot stellar core; the ultraviolet radiation causes the gas to fluoresce as the planetary nebula.



 Mayall's Object

Arp 148, also known as Mayall's Object, is the result of two colliding galaxies located 500 million light years away within the constellation of Ursa Major. This collision resulted in a ring-shaped galaxy and a long-tailed companion. The shockwave effect produced from the collision first drew matter into the centre and then caused it to spew outwards in an expanding ring.

The object was discovered on 13 March 1940 by Nicholas U. Mayall of the Lick Observatory, using the Crossley reflector.



EQUINOX TRAILS
  

This image was captured by Juan Carlos Casado, taken from Teide Observatory (IAC) in the Canary Islands. The image was taken during the spring equinox of 2010, using a full format DSLR with a fisheye lens, placed in a fixed position toward the west. The photographer first made exposures for the Sun every 30 seconds with a solar filter placed on the lens for the duration of about 6 hours (the bold rectilinear trail is the sun). After the sun set, exposures were made continuously (30 seconds each) to capture the motion of stars for about 5 hours. All images were then combined on the computer, and the distortion from the fisheye was also fixed.

The image you see is the result: the sun is passing the celestial equator while startrails on each celestial hemisphere (North and South) are curved in the opposite direction. The North Star (Polaris) is to the right of the image, above the solar laboratory "Pyramid Van der Raay" (known as Pyramid). The Teide Volcano (3,710 metres height) is in the background and La Palma Island is on the horizon



WASP-12B: THE HOTTEST KNOWN EXOPLANET

WASP 12b is located around a star 867 light years away from Earth in the constellation Auriga. It was discovered in 2008 and is currently the hottest known exoplanet, with a surface temperature of about 2,200°C (4,000°F). It is almost twice the size of Jupiter and orbits about 3.4 million kilometres out from its parent star; as the planet is so close to its star, the star’s gravity pulls it into a slight egg like shape. In contrast, Earth orbits about 150 million kilometres out from the sun. WASP-12b orbits its parent star once every Earth day.

On May 20, 2010, the Hubble Space Telescope spotted WASP-12b being consumed by its star. While scientists had been aware of such phenomena, this was the first time such an event had been observed so clearly. It is estimated that the planet has 10 million years left of its life. NASA's Spitzer Space Telescope discovered that WASP-12b has more carbon than oxygen, making it the first carbon-rich planet ever observed. As concentrated carbon can take the form of diamond, it is possible that carbon-rich gas planets could have abundant diamond in their interiors.
Also in 2010, scientists at the Open University found that WASP-12b's parent star dimmed at times when the exoplanet passed in front of the star as seen from Earth sooner in ultraviolet wavelengths than in optical wavelengths during transits. At the time the astronomers thought the signal was from a cloud of material being stripped away from the planet by the parent star. Astronomers inferred that the planet had a magnetosphere, based on observations using the Hubble Space Telescope.

In 2011, Aline Vidotto and Ph.D. student Joe Llama used computer simulations to see whether the planet might create compress the material in front of it to create a bowshock ahead of it, acting like a shield which protects it while it journeys through a supersonic headwind while orbiting so close to its parent star. The star that WASP-12b orbits is a yellow dwarf that spews out charged particles much like the sun's solar wind. The researchers simulated magnetic fields for the planet and then observed the interactions between the magnetic fields and the solar wind streaming from the nearby star.

Research such as this gives astronomers another tool with which to measure the strength of planetary magnetic fields. The team has been able to examine other exoplanets and found that their orbital conditions would allow a similar bowshock; bowshocks could be more common than previously thought.

The image is an artist’s impression of WASP-12b, showing the star's gravity pulling material off the planet into a disk around the star.



TITAN HAS SEASONAL CHANGES

Saturn’s Moon Titan has been subject to detailed observations for 30 years now, which covers one solar orbit for the planet. Scientists lead by Dr Athena Coustenis from the Paris-Meudon Observatory in France, have analysed data gathered over these years and found that the changing seasons of Titan affect it more than previously thought.

The recent analysis has shown that there are seasonal changes in atmospheric temperatures, chemical composition and circulation patterns, particularly at the poles. Hydrocarbon lakes form around the northern polar region during winter because of colder temperatures and condensation. The haze layer around the northern pole is also significantly reduced during the equinox because of the atmospheric circulation patterns.

The dominant energy source, and also the main cause of these cycles, is solar radiation. This radiation breaks up the nitrogen and methane present and creates more complex molecules like ethane. Titan is inclined at 27 degrees which is similar to Earth’s inclination, meaning the seasons on both worlds are caused by sunlight reaching different areas with varying intensity due to the tilt.

Data was analysed from many different missions, including Voyager 1 (1980), the Infrared Space Observatory (1997), and Cassini (2004 onward), and was also complemented by ground-based observations. The seasons on Titan each span around 7.5 years and it takes 29.5 years for Saturn to orbit the Sun.

The image is an impression of Titan’s surface, based on data from the Huygens mission, giving an idea the view from the ground.



PLANET FORMATION IN OUR SOLAR SYSTEM MAY HAVE BEEN STAGGERED

New research by Tagir Abdylmyanov, an associate professor from Kazan State Power Engineering University in Russia, suggests our solar system’s planets may have formed at differing times, which were determined by shock waves which came flowing from the young sun. The research also suggests Earth, Mercury, Venus and Mars are the youngest planets in the solar system. This work presents a new way in which scientists can predict where planets form in young solar systems.

Abdylmyanov based his work on a solar system formation theory proposed by Japanese astrophysicists in 1985 in the book "Protostars and Planets II”. In it, the Japanese scientists suggested that the solar system began with a solar nebula that gradually evolved to form clumps of dust that gelled to make protoplanets and then planets. Abdylmyanov adapted his own mathematical models to take this previous research even further, by suggesting the planets formed at different times instead of all at the same time.

Abdylmyanov modelled the movement of particles in fluids and gases inside the gas cloud from which our sun formed and theorised that the movements of this material would have created shockwaves as the sun evolved. His work suggests that each series of shockwaves created a series of debris rings around the sun that accreted over millions of years into planets. The modern distance between the orbits of the planets is assumed to be the result of the action of the shock waves and the solar activity when the star was forming.

The first series of shockwaves, which came from short but very rapid changes in solar activity, would have created the protoplanetary rings for Uranus, Neptune and dwarf planet Pluto, very close in time to the sun’s birth. 3 million years later, less powerful shockwaves created the debris ring which ultimately became Saturn, and then 500,000 years later Jupiter’s debris ring may have formed. Shock waves about a million years after that, when the sun was far calmer, created the asteroid belt; 500,000 years after that would see the creation of the protoplanetary rings for Mercury, Venus, Earth and Mars.

Abdylmyanov’s research also shows that gas and dust accretions could have caused accelerated planetary formation from the protoplanetary rings. This would likely favour the formation of only one planet from that ring, rather than several.

Scientists can study the brightness of stars in the process of forming to find indications as to the intensity of the stellar shock waves, and then may be able to predict the location of planets around stars millions of years before they have formed.