Discovered in 2016 by astronomers at the WASP-South survey, WASP-121b is 1.87 times bigger than Jupiter and 1.18 times more massive.
Its host star, WASP-121 (TYC 7630-352-1), is an active F6-type main-sequence star about 1.5 times the size of the Sun.
The WASP-121 system is located 881 light-years away in the constellation Puppis.
WASP-121b is a so-called ‘hot Jupiter’ and takes just 1.3 days to orbit WASP-121. It is so close to the parent star that if it got any closer, the star’s gravity
would start ripping it apart.
Astronomers estimate the planet’s temperature to be about 4,600 degrees Fahrenheit (2,500 degrees Celsius), hot enough to boil some metals.
Previous research found possible signs of a stratosphere on WASP-33b as well as some other hot Jupiters.
The new study presents the best evidence yet because of the signature of hot water molecules that astronomers observed for the first time.
This result is exciting because it shows that a common trait of most of the atmospheres in our solar system - a warm stratosphere - also can be found in exoplanet
atmospheres.
Theoretical models have suggested stratospheres may define a distinct class of ultra-hot planets, with important implications for their atmospheric physics and chemistry.
These observations support this picture.
To study the stratosphere of WASP-121b, the team observed a secondary eclipse of the planet using the Wide Field Camera onboard the NASA/ESA Hubble Space Telescope and the Infrared Array Camera onboard NASA’s Spitzer space telescope.
The researchers analysed how different molecules in the stratosphere react to particular wavelengths of light.
Water vapour in the planet’s atmosphere, for example, behaves in predictable ways in response to certain wavelengths of light, depending on the temperature of the water.
Starlight is able to penetrate deep into a planet’s atmosphere, where it raises the temperature of the gas there.
This gas then radiates its heat into space as infrared light.
However, if there is cooler water vapour at the top of the atmosphere, the water molecules will prevent certain wavelengths of this light from escaping to space. But if the water molecules at the top of the atmosphere have a higher temperature, they will glow at the same wavelengths. The emission of light from water means the temperature is increasing with height.
In Earth’s stratosphere, ozone gas traps ultraviolet radiation from the Sun, which raises the temperature of this layer of atmosphere.
Other solar system bodies have stratospheres, too; methane is responsible for heating in the stratospheres of Jupiter and Saturn’s moon Titan, for example.
In solar system planets, the change in temperature within a stratosphere is typically around 100 degrees Fahrenheit (about 56 degrees Celsius).
On WASP-121b, the temperature in the stratosphere rises by 1,000 degrees Fahrenheit (560 degrees Celsius).
The astronomers do not yet know what chemicals are causing the temperature increase in WASP-121b’s atmosphere.
Vanadium oxide and titanium oxide are candidates, as they are commonly seen in brown dwarfs.
Such compounds are expected to be present only on the hottest of hot Jupiters, as high temperatures are needed to keep them in a gaseous state.

Scientists from IIT Guwahati have synthesised mats made of silk-proteins and bioactive glass fibres that they believe can assist the growth of bone cells and repair worn-out joints in arthritis patients. The disease most commonly affects joints in the knees, hips, hands, feet, and spine and is marked by the breakdown of joint cartilage and underlying bones. Left untreated, it can cause severe pain, swelling, and eventually limited range of movement. Current clinical treatment methods are limited by lack of viable tissue substitutes to aid the repair process To develop a suitable tissue substitute, scientists looked into the natural bone-cartilage interface and tried to mimic it synthetically in lab conditions. Knee osteoarthritis is the most common bone and joint disease in India. The available clinical grafts were expensive. The scientists used silk, a natural protein to fabricate electro-spun mats to mimic the cartilage portion and bioactive glass to develop a composite material, similar to the natural tissue. For the mat, scientists used a kind of silk easily available in northeast India. Muga [Assam] silk is endowed with properties that enhance the healing process. The researchers adopted a green fabrication approach for the developing the silk composite mats - electrospinning. It is similar to knitting, except that it utilises electric high-voltage force to draw ultrafine fibres. A layer by layer approach was followed, where the bone layer was first formed, on top of which the cartilage layer was developed. The resulting composite mat resembled the architecture of the bone-cartilage interface. To assist the regenerative process, the mats would be grafted in the defected joint with cells harvested from the patient.

Indian Space Research Organisation (ISRO) has deployed an indigenous regional positioning system named as “Navigation with Indian Constellation” (NavIC). It consists of seven satellites in a constellation to provide Position, Navigation and Timing (PNT) services in Indian mainland and surrounding region up to 1500 Km. It provides two types of services viz. Standard Positioning Service (SPS) and Restricted Service (RS). A budget of INR 1420 Crore has been approved by the Government for the realisation of the system including 7 in-orbit satellites, 2 satellites as ground spare and associated ground segment. ISRO has established the required space segment of the NavIC system for providing signal in space enabling position, navigation and timing information and it can support commercial civil applications. Indian entrepreneurs are being enabled for providing services through NavIC receiver system and requisite information has been made available in public domain. The demonstrations for vessel tracking, vehicle tracking, messaging services for fishermen, timing applications have been conducted. Mobile-Apps for navigational alerts across maritime jurisdictions is developed and tested for the Fishermen community using first generation NavIC receivers. Various types of user receivers are being developed indigenously involving Indian industry and discussions amongst government departments, user-receiver manufacturers, system integrators and service providers are taking place for the usage of NavIC system. While the space and ground segment of the NavIC system has been established and demonstrations of various applications/ services have been conducted, the time required for it to become fully operational depends on the service providers making the services available in the market. It may take couple of years to become fully operational in the market

A partial eclipse of the Moon will occur on August 7,2017 which will begin from h. 22-52 IST and will continue upto h. 00-49 IST on August 8, 2017. Only a small fraction of the Moon will come under Earth’s shadow at maximum eclipse. This partial eclipse will be visible from all places of India. The eclipse will be visible in the region covering Western Pacific Ocean,Oceania, Australia, Asia, Africa, Europe and Antarctica. The entire partial eclipse will be visible from central and east Africa, central Russia, China, India , the Far East and most of Australia. The places from where the beginning of the umbral phase will be visible at the time of moonset are western parts of North Pacific Ocean and South Pacific Ocean. The places from where the ending of umbral phase will be visible at the time of moonrise are north western part of Africa, eastern parts of Spain, France and Germany. The circumstances of the eclipse are as follows: Eclipse will begin at 10:52 pm, reach the middle phase at 11:51 and close at 12:49 am. Magnitude of the eclipse = 0.251 (Moon’s diameter being taken as 1.0) Duration of the eclipse: 1 h 57 m. The next eclipse of the Moon will occur on January 31, 2018, which will be a total lunar eclipse and will be visible from India.