Saturday, August 20, 2016

Venus-Like Exoplanet GJ 1132b Might  have Thin Oxygen Atmosphere, But Not Life (शुक्र ग्रह की तरह दिखने वाले ग्रह  GJ 1132b  पर  ऑक्सीजन  है परन्तु जीवन नही है /)


Astronomers believe that distant exoplanet GJ 1132b, which was discovered last year, might have an atmosphere despite being an extremely hot world with a temperature of nearly 450 degrees Fahrenheit.

The study, published in the Astrophysical Journal, showed that the Venus-like planet, about 39 light years away from Earth, might have a thin and wispy atmosphere, indicating the presence of oxygen.



"On cooler planets, oxygen could be a sign of alien life and habitability," said Laura Schaefer, an astronomer at Harvard-Smithsonian Center for Astrophysics and lead author of the study, in a statement. But on a hot planet like GJ 1132b, it's a sign of the exact opposite - a planet that's being baked and sterilized."

For the study, the researchers assumed that GJ1132b began with a steamy, water-rich atmosphere. With an extremely close orbit to its host star, approximately 1.4 million miles, the planet could be bombarded with ultraviolet light. The water molecules in the atmosphere of the planet would be broken apart by the UV light into hydrogen and oxygen. Because hydrogen is lighter, it could escape into space readily, while some of the oxygen could linger behind.
Water vapor could act as a powerful greenhouse gas, trapping the intense heat of the host star inside GJ113b. Due to this, the surface of the planet could stay molten for millions of years.
Using a magma ocean-atmosphere model, the researchers believe that a magma ocean could interact with the atmosphere by absorbing about 10 percent of the oxygen, while the remaining 90 percent may stream off to space or linger around the planet.

With their findings, researchers could catch some glimpse on how the planet Venus evolved. Previous study suggests that Venus might contain Earth-like amounts of water in its early life and was broken down by the sunlight. However, Venus shows few signs of lingering oxygen.
To confirm if GJ1132b have some oxygen lingering in its atmosphere, researchers need to observe the planet using next-generation telescope like the Giant Magellan Telescope and James Webb Space Telescope to detect and analyze it.

Tuesday, July 5, 2016

Juno

Juno Spacecraft reaches Jupiter (जूनो अंतरिक्ष यान बृहस्पति ग्रह तक पहुँचा)


NASA's probe mission Juno reached Jupiter and started orbiting it. This is a big step of NASA in space to reveal hidden secrets of Gigantic planet. 


Juno is a NASA New Frontiers mission currently orbiting the planet Jupiter. Juno was launched from Cape Canaveral Air Force Station on August 5, 2011 and arrived on July 4, 2016. The spacecraft is in a polar orbit to study Jupiter's composition, gravity field, magnetic field, and polar magnetosphere. Juno will also search for clues about how the planet formed, including whether it has a rocky core, the amount of water present within the deep atmosphere, mass distribution, and its deep winds, which can reach speeds of 618 kilometers per hour (384 mph).

Juno is the second spacecraft to orbit Jupiter, following the Galileo probe which orbited from 1995–2003.

The Juno spacecraft is powered by solar arrays, commonly used by satellites orbiting Earth and working in the inner Solar System, whereas radioisotope thermoelectric generators are commonly used for missions to the outer Solar System and beyond. For Juno, however, three solar array wings, the largest ever deployed on a planetary probe, play an integral role in stabilizing the spacecraft and generating power.


Jupiter Planet














































The spacecraft's name comes from Greco-Roman mythology. The god Jupiter drew a veil of clouds around himself to hide his mischief, but his wife, the goddess Juno, was able to peer through the clouds and see Jupiter's true nature.The mission had previously been referred to by the backronym JUpiter Near-polar Orbiter in a list of NASA acronyms.