Earth first "Trojan" asteroid spotted by WISE.

Astronomers studying observations taken by NASA's Wide-field Infrared Survey Explorer (WISE) mission have discovered the first known "Trojan" asteroid orbiting the sun along with Earth.

Trojans are asteroids that share an orbit with a planet near stable points in front of or behind the planet. Because they constantly lead or follow in the same orbit as the planet, they never can collide with it. In our solar system, Trojans also share orbits with Neptune, Mars and Jupiter. Two of Saturn's moons share orbits with Trojans.

Scientists had predicted Earth should have Trojans, but they have been difficult to find because they are relatively small and appear near the sun from Earth's point of view.

The WISE telescope sees the entire sky in infrared light, so warmer objects are easier to spot. This asteroid is probably around the freezing point of water or so, which, to an astronomer, is pretty warm. The team's hunt resulted in two Trojan candidates. One called 2010 TK7 was confirmed as an Earth Trojan after follow-up observations with the Canada-France-Hawaii Telescope on Mauna Kea in Hawaii.

The asteroid is roughly 1,000 feet (300 meters) in diameter. It has an unusual orbit that traces a complex motion near a stable point in the plane of Earth's orbit, although the asteroid also moves above and below the plane. The object is about 50 million miles (80 million kilometers) from Earth. The asteroid's orbit is well-defined and for at least the next 100 years, it will not come closer to Earth than 15 million miles (24 million kilometers).

A handful of other asteroids also have orbits similar to Earth. Such objects could make excellent candidates for future robotic or human exploration. Asteroid 2010 TK7 is not a good target because it travels too far above and below the plane of Earth's orbit, which would require large amounts of fuel to reach it.

The WISE telescope has observed more than 155,000 asteroids in the main belt between Mars and Jupiter, and more than 500 NEOs, discovering 132 that were previously unknown.

Hubble Space Telescope discovers another moon around Pluto

Hubble Space Telescope's keen vision has found yet another moon orbiting the distant, icy dwarf planet Pluto. This discovery expands the number of Pluto's known satellite system to four moons. The tiny, new satellite — temporarily designated P4 — was uncovered in a Hubble survey searching for rings around the frigid dwarf planet.

The new moon is the smallest moon yet discovered around Pluto. It has an estimated diameter of 8 to 21 miles (13 to 34 km). By comparison, Charon, Pluto's largest moon, is 648 miles (1,043 km) across, and the other moons, Nix and Hydra are in the range of 20 to 70 miles in diameter (32 to 113 km).

The new moon is located between the orbits of Nix and Hydra, which Hubble discovered in 2005. Charon was discovered in 1978 at the U.S. Naval Observatory and first resolved using Hubble in 1990 as a separate body from Pluto.

The dwarf planet's entire moon system is believed to have formed by a collision between Pluto and another planet-sized body early in the history of the solar system. The smashup flung material into orbit around Pluto, which then coalesced into the family of satellites now seen.

Lunar rocks returned to Earth from the Apollo missions led to the theory that our Moon was the result of a similar collision between Earth and a Mars-sized body 4.4 billion years ago. Scientists believe material blasted off Pluto's moons by micrometeoroid impacts may form rings around the dwarf planet, but the Hubble photographs have not detected any so far.

P4 was first seen in a photo taken with Hubble's Wide Field Camera 3 on June 28, 2011. It was confirmed in subsequent Hubble pictures taken on July 3 and July 18. The moon was not seen in earlier Hubble images because the exposure times were shorter. There is a chance it appeared as a very faint smudge in 2006 images, but was overlooked because it was largely obscured by an imaging artifact, called a diffraction spike.

The finding is a result of ongoing work to support NASA's New Horizons mission, scheduled to fly through the Pluto system in 2015. The mission is designed to provide new insights about worlds at the edge of our solar system. Hubble's mapping of Pluto's surface and discovery of its satellites have been invaluable to planning for New Horizons' close encounter.

Dawn arrives at Vesta

Dawn Space Probe

NASA's Dawn spacecraft has returned the first close-up image after beginning its orbit around the giant asteroid Vesta. On Friday, July 15, Dawn became the first probe to enter orbit around an object in the main asteroid belt between Mars and Jupiter.

Vesta is 330 miles (530 kilometers) in diameter and the second most massive object in the asteroid belt. Ground- and space-based telescopes have obtained images of Vesta for about two centuries, but they have not been able to see much detail on its surface. This is beginning the study of arguably the oldest extant primordial surface in the solar system. This region of space has been ignored for far too long. So far, the images received to date reveal a complex surface that seems to have preserved some of the earliest events in Vesta's history.

Vesta is thought to be the source of a large number of meteorites that fall to Earth. Vesta and its new neighbour Dawn, are currently approximately 117 million miles (188 million kilometers) away from Earth. The Dawn team will begin gathering science data in August. Observations will provide unprecedented data to help scientists understand the earliest chapter of our solar system. The data also will help pave the way for future human space missions.

The probe carries instruments to detect the mineral and elemental composition of its surface rocks. It will be looking for evidence of geological processes such as mountain building and rifting.

The Dawn science team is keen to understand how Vesta's surface has been remodelled over time by impacts and even lava flows. Dawn's remote sensing instruments will also be able to discern something of the asteroid's internal structure. The expectation is that scientists will confirm it has a metallic core. From the outside, Vesta looks like a punctured football, the result of a colossal collision sometime in its past that knocked off its south polar region.

After traveling nearly four years and 1.7 billion miles (2.8 billion kilometers), Dawn accomplished the largest propulsive acceleration of any spacecraft, with a change in velocity of more than 4.2 miles per second (6.7 kilometers per second), due to its unique ion engines. The engines expel ions to create thrust and provide higher spacecraft speeds than any other technology currently available.

Dawn will spend one year orbiting Vesta, then travel to a second destination, the dwarf planet Ceres, arriving in February 2015.

India notches another space success

It was on 15th July, 2011 that the proud nation put another feather on the cap on the launch of GSAT 2011 from the space station at Shriharikota. The launch occurred from the Satish Dhawan space center at 4.48pm when the massive satellite was successfully placed into its elliptical orbit.

“I am extremely happy to state that the PSLV-C17 GSAT12 mission is successful. The launch vehicle injected the satellite very precisely into the intended orbit,” said the ISRO chairman K.Radhakrishnan. The scientists could not refrain themselves from breaking into cheers seeing one of their most wanted dream come true.

GSAT aims at extending the capacity of INSAT for increased facilities related to medicine, resource mapping and education facilities. Due to the failures in the previous two launches in April and December, 2010, the ISRO team without any further experimentation used PSLV for the most safe transmission medium. The total time mission for GSAT is about eight years with an estimated cost of about Rs.2 crore.

The main reason for the launch was to meet the country’s demand for increased transponders which is a device with a transmitter and receiver that will generate a reply signal on proper electronic interrogation. Pleased and delighted with the success of the launch the ISRO chairman has also declared the team’s future plans for designing reliable GSLV cryogenic stage.

The Prime minister greeted the whole ISRO team for their success which in turn promised to keep their determination and dedication alive forever for the country’s sake.

One Neptunian Year.....!!!!!

On Tuesday, July 12th, Neptune will have completed one full circuit around the Sun since its discovery around midnight on the night of September 23-24, 1846. The great icy world was first pinpointed 164.79 years ago. And as Neptune takes 164.79 Earthly years to circle the sun, it is only now completing its first full orbit since its detection by humans. And there is much to commemorate – for Neptune's discovery marked a turning point in astronomy. Its existence was revealed, not through a serendipitous observation by an astronomer but by the careful work of mathematicians. They calculated that perturbations in the orbit of Uranus, then thought to be the sun's most distant planet, could only be explained by the existence of another, even remoter world whose gravity was affecting Uranus's path.

John Adams and Urbain Le Verrier carried out independent analysis of discrepancies in the observed and calculated positions of Uranus and predicted in 1845 the mass and orbit of the perturbing body. The planet was discovered on September 23, 1846 by Johann Galle and Heinrich d’Arrest from Berlin Observatory very near the predicted position. An international dispute arose between the English and French over priority and the right to name the new planet; they are now jointly credited with Neptune’s discovery.

As to the nature of the planet, this was only revealed in full in 1989 when the US probe Voyager 2 swept past it and sent back images of a seemingly serene blue world – though later analysis revealed dark spots on its surface that are vast cyclonic storms.

Neptune’s composition is probably similar to Uranus: various “ices” and rock with about 15%hydrogen and little helium. Like Uranus, but unlike Jupiter and Saturn, it may not have a distinct internal layering but rather to be more or less uniform in composition. But there is most likely a small core of rocky material, about the mass of the Earth. Its atmospere is mostly hydrogen and helium with a small amount of methane.

Neptune’s blue color is largely the result of absorption of red light by methane in the atmosphere but there is some additional as yet unidentified chromosphere which gives the clouds their rich blue tint. Like typical gas planet, Neptune has rapid winds confined to bands of latitude and large storms or vortices. Neptune’s winds are the fastest in the solar system, reaching 2000 km/hour.

Neptune also has rings. Earth based observations showed only faint arcs of complete rings, but Voyager 2’s image showed them to be complete rings with bright clumps. Like Uranus and Jupiter, Neptune’s rings are very dark but their composition is unknown. Neptune’s rings have been given names: the outermost is Adams which contains three prominent arcs named as Liberty, Equality and Fraternity. Next is an unnamed ring then Leverrier and finally the faint but broad Galle.

This is an awkward time to observe Neptune; it doesn't reach a reasonable height above the horizon until the wee hours of the morning. Moreover, it won't appear anywhere near its discovery position with respect to the stars, due to the fact that Earth is in quite a different part of its orbit. But if you want to view Neptune anyway, it's easy to do with decent telescopes and binoculars.

Neptune is well-placed in the early evening sky starting in September, and it will appear extremely close to its discovery position among the stars from mid-October through December.

Last Shuttle...

Space shuttle Atlantis’ STS-135 mission will be NASA’s last space shuttle flight. Atlantis will carry four astronauts and the multi-purpose logistics module Raffaello to the International Space Station on 8th of July. During the 12-day flight, mission specialists will use the shuttle’s robotic arm to lift Raffaello from the shuttle’s payload bay and hand it off to the station’s robotic arm for temporary attachment to the Harmony node segment. Raffaello contains logistics, supplies and hardware for transfer to the station. Atlantis also will carry a system to investigate the potential for robotically refueling existing satellites and return a failed ammonia pump to help NASA better understand the failure mechanism and improve pump designs for future systems. STS-135 is Atlantis’ 33rd and final flight, the 135th and final space shuttle mission, and the 37th U.S. flight to the space station.