OLYMPUS MONS

Olympus mons is a very large volcano on planet March and  it may be  the largest volcano in our solar system. This giant Martian peak, which was photographed by Mariner 9 which orbited the planet March during 1971  and 1972 ,The olympus mons rises almost 22 kilometers(13.6 miles or 72,000 ft) high and measures 550 km across. By comparison, Earth's largest volcano, Mauna Loa in Hawaii, rises 4,169 meter(13,678 ft) above sea level and measures 120 km across. Such large volcanoes can exist on Mars because of the low gravity and lack of surface tectonic motion. Olympus Mons is a shield volcano.A shield volcano is a type of volcano usually built almost entirely of fluid lava flows. They are named for their low profile, resembling a warrior's shield lying on the ground. This is caused by the highly fluid (low viscosity) lava they erupt which travels farther than lava erupted from stratovolcanoes. This results in the steady accumulation of broad sheets of lava, building up the shield volcano's distinctive form. The shape of shield volcanoes is due to the low viscosity of their mafic lava.

Mauna Kea, Hawaiʻi, a shield volcano on the Big Island of Hawaii

The volcano is located in Mars's western hemisphere at approximately 18.65°N 226.2°E, just off the northwestern edge of the Tharsis bulge. The western portion of the volcano lies in the Amazonis quadrangle (MC-8) and the central and eastern portions in the adjoining Tharsis quadrangle (MC-9).

Olympus Mons is still a relatively young volcano. Although it has taken billions of years to form, some regions of the mountain may be only a few million years old, relatively young in the lifetime of the solar system. As such, Olympus Mons may still be an active volcano with the potential to erupt.

DESCRIPTION:

The typical atmospheric pressure at the top of Olympus Mons is 72 pascals, about 12% of the average Martian surface pressure of 600 pascals. Both are exceedingly low by terrestrial standards. By comparison, the atmospheric pressure at the summit of Mount Everest is 32,000 pascals, or about 32% of Earth's sea level pressure. Olympus Mons shows that there is a composition of 44% silicates, 17.5% iron oxides, giving the planet its red coloration, 7% aluminum, 6% magnesium, 6% calcium, and particularly high proportions of sulfur oxide with 7%. These results point to the fact that the surface is largely composed of basalts and other mafic rocks, which would have erupted as low viscosity lava flows and hence lead to the low gradients on the surface of the planet. After plate tectonics ceased on Mars, hotspots, which cause volcanoes such as these, remained under the same areas for a very long time, and the volcanoes kept growing. Olympus Mons is supported by a 70 km (43 mi) thick lithosphere.

Vertical comparison of Olympus Mons with Mount Everest (shown sea-level-to-peak) and Mauna Kea on Earth 

The main difference between the volcanoes on march and earth is their size,volcanoes in the tharsis region of march are 10 to 100 times larger than those anywhere on earth. The lava flows on martian surface are observed to be much longer ,probably a result of higher eruption rates and lower surface gravity.


Another reason of existence of this kind of giant volcanoes on march is because the crust on march doesnot move like the crust on planet earth. On earth the ,the hot spots remain stationary but the crustal plates are moving above them .The Hawaiian island result from the northwesterly movement of   pacific plate over a stationary hotspot producing lava. As the plate moves over the hotspot, new volcanoes are formed and the existing ones become extinct.This distributes the total volume of lava among many volcanoes rather than one large volcano. On march the crust remains stationary and the lava piles up in one ,very large volcano.   


Mt. Everest might be the tallest mountain on the earth, but it is nothing in compared to the olympus mons on our nearest  red planet or March.The olympus mons is almost three times that the height of the Mt. Everest. Scientist estimate that this giant volcano last time erupted lava onto the martian surface was between 20-200m million years ago,around the same that dinosaurs ruled on our planet.While some scientist that this last eruption on olympus mons marks the last breath of volcanic activity on march , Others suggest this monstrous volcano is still active despite being dormant for millions of years. 

THANKS FOR READING.
Reference:wikipedia
image credit:nasa

SOLAR WIND

The solar wind is a stream of charged particles, primarily electrons and protons, emitted by the sun(star) which penetrate  the solar system at speeds as high as 300-800km/s.This type of emitting charged particles which are released from the upper atmosphere of the Sun, called the corona.In 1859, it was first suggested by British astronomer Richard C. Carrington.
It was not until 1962 that solar wind was proved to exist.  The spacecraft Mariner II directly detected the solar wind on its way to Venus.

The Wind spacecraft has spent much of its 20 years in space out in front of the magnetic fields – the magnetosphere – that surrounds Earth, observing the constant stream of particles flowing by from the solar wind.
IMAGE CREDIT:NASA

The process in which two light nuclei combine (at extremely high temperature)to form a single heavier nucleus is called nuclear fusion.Fusion is the source of energy in sun and stars . The sun has been radiating energy at the rate of 3.8✖ 10^26 J/S  for several billion years without showing any sign of cooling off. A satisfactory explanation for this phenomenon was given by H. Bethe in 1939. hydrogen nuclei ,i.e protons are most abundant in the body of sun and stars . At extremely high temperature which exits in interior of the sun and stars ,protons fuse together to form helium nuclei ,liberating a huge amount of energy.
The solar wind refers to the steady stream of highly charged particles that continually blow of the sun in all direction. The corona which is outer atmosphere of the sun expanding into the space and caused this.You can see it as a glowing halo around the sun during a solar eclipse.     

Hydrogen atoms heat up to more than 1 million °C on the solar surface, then decompose into electron and protons.They are called plasmas. The plasma gas is forced to burst out from the solar surface by the high pressure it has.The plasma gas then runs through interplanetary space at ultra-high-speed as fast as 300-800 km per second!That is the solar wind.

The solar wind is observed to exist in two fundamental states, termed the slow solar wind and the fast solar wind, though their differences extend well beyond their speeds. In near-Earth space, the slow solar wind is observed to have a velocity of 300–500 km/s, a temperature of 1.4–1.6×10^6 K and a composition that is a close match to the corona. By contrast, the fast solar wind has a typical velocity of 800 km/s. The slow solar wind is twice as dense and more variable in nature than the fast solar wind.

The slow solar wind appears to originate from a region around the Sun's equatorial belt that is known as the "streamer belt", The exact coronal structures involved in slow solar wind formation and the method by which the material is released is still under debate.

Average solar wind parameters at 1 AU, for the time around solar activity minimum.

                                                      slow wind                       fast wind

Flow speed                                    300–500 km s−1            500–800 km s−1

Proton density                               10.7 cm−3                      3.0 cm−3

Proton flux density                        3.7 × 10^8 cm−2 s−1     2.0 × 10^8 cm−2 s−1

Proton temperature                        3.4 × 10^4 K                  2.3 × 10^5 K

Electron temperature                     1.3 × 10^5 K                  1 × 10^5 K

Momentum flux density                2.12 × 10^8 dyn cm−2   2.26 × 10^8 dyn cm−2

Total energy flux density               1.55 erg cm−2 s−1         1.43 erg cm−2 s−1

Helium content                              2.5%, variable                3.6%, stationary

Sources                                          Streamer belt                  Coronal holes

The red and blue arrows indicate solar wind speed; longer arrow represents higher speeds.

 🗙Solar minimum, when sunspots are rare.

  🗙Solar maximum, when the Sun is very active and    sunspots are common.


Sunspot are temporary phenomena on the sun’s surface that appear visibly as dark spots compared to surrounding regions.

Plasma has the character of embedding magnetic field. When the coronal gas streams from the Sun into interplanetary space, it pulls out the Sun‛s magnetic field lines.The magnetic field lines are stretching out of the Sun, forming huge spirals because of the Sun‛s rotation.

A coronal mass ejection (CME) is a significant release of plasma and magnetic field from the solar corona. They often follow solar flares and are normally present during a solar prominence eruption. The plasma is released into the solar wind.Coronal mass ejections are often associated with other forms of solar activity, but a broadly accepted theoretical understanding of these relationships has not been established. CMEs most often originate from active regions on the Sun's surface, such as groupings of sunspots associated with frequent flares. Near solar maxima, the Sun produces about three CMEs every day, whereas near solar minima, there is about one CME every five days.

It affects it by the intense clouds of high energy particles that it often contains which are produced by solar storms. When these clouds, called coronal mass ejections, make their way to the Earth, they collide with the magnetic field of the Earth and cause it to change its shape.
 As you have already learned, the Earth is also a huge magnet with north and south poles.The geomagnetic field lines are blocking the solar wind like a barrier. This barrier, however, cannot entirely shield the solar wind.When the solar wind buffets the geomagnetic field, its huge energy penetrates into the Earth‛s magnetosphere in various forms.The particles then leak through the magnetic field of the Earth, particularly near the north and south poles, and cause still more changes to the magnetic field of the Earth, this time at even lower altitudes closer to the ground. These changes can produce many problems with electrical equipment.


Aurora

Aurora is one of the phenomena caused by the energy from the Sun! An aurora (plural: auroras),sometimes referred to as polar lights, northern lights (aurora borealis) or southern lights (aurora australis), is a natural light display in the Earth's sky, predominantly seen in the high latitude (Arctic and Antarctic) regions.

 Auroras are produced when the magnetosphere is sufficiently disturbed by the solar wind that the trajectories of charged particles in both solar wind and magnetospheric plasma, mainly in the form of electrons and protons, precipitate them into the upper atmosphere (thermosphere/exosphere) due to Earth's magnetic field, where their energy is lost.The solar wind, the flow of plasmas, creates the aurora by colliding with the atoms and molecules of the Earth‛s upper atmosphere.

Cosmic rays are traveling from far away in space. They are high energy particles and are harmful to life on the ground, if they hit the Earth directly.Now, the solar wind with magnetic fields plays a role as a barrier to protect the Earth from being directly hit by cosmic rays! We can say that life is shielded by the magnetized solar wind. the Sun is blasting out 1 million tons of solar wind every second.The Sun loses a mass of 30 trillion tons per year in the form of solar wind.In the meantime, the total mass of the Sun is 30 trillion multiplied by 70 trillions.Simply calculating, it takes 70 trillion years for the Sun to lose its whole mass.


INFLUENCE OF THE SOLAR WIND ON EARTH

The solar wind has a significant influence on our ionosphere, the Earth’s magnetic field, on earth’s Aurora, and on telecommunication systems.

HOW DOES SOLAR WIND AFFECT HUMAN HEALTH

There is an increased cancer risk for astronauts in space, who are hit by the particles of the solar wind, and there may similarly be an increased risk of cancer, or cell damage to humans located at the magnetic poles. (e.g. people gathered to watch the Auroras)

WHY DO WE STUDY THE SOLAR WIND?

The solar wind is an important research topic.

 There are a large number of phenomena, which we don’t or only partially understand.

 One hopes that a better understanding of the solar wind will give us insight in the behavior of stars.

thanks for reading.

reference :wiki

Here You Know Everything About NAVIC

Yes! Indian’s very first GPS system is on public use in early 2018. Now  India has its own GPS system with more accuracy, Cause whereas America  use 24 satellite all around the world , India use 7 satellite only for India . So more accurate all ready. As this project name NAVIC is given by the  PM of india Narenda Modi . NAVIC( NAVigation with Indian Constellation) means sailor in Hindi and many other language.



India needed a constellation of seven satellites in space to complete its Indian Regional Navigation Satellite System (IRNSS), a feat the country was able to achieve on April 28, 2016, when Indian Space Research Organisation (Isro) successfully launched IRNSS-1G, the seventh satellite in the series, and guided it to its orbit. India needed a constellation of seven satellites in space to complete its Indian Regional Navigation Satellite System (IRNSS), a feat the country was able to achieve on April 28, 2016, when Indian Space Research Organisation (Isro) successfully launched IRNSS-1G, the seventh satellite in the series, and guided it to its orbit.
NavIC has helped India enter the club of select countries, which have their own positioning systems. Besides America's GPS, Russia has its GLONASS and European Union, its Galileo. China is also in the process of building Beidou Navigation Satellite System.
As part of the project, the INDIAN SPACE RESEARCE ORGANISATION (ISRO) opened a new satellite navigation center within the campus of ISRO deep space network  (DSN) at Byalalu, in Karnataka on 28 May 2013 A network of 21 ranging stations located across the country will provide data for the  orbital determination  of the satellites and monitoring of the navigation signal.

A goal of complete Indian control has been stated, with the space segment, ground segment and user receivers all being built in India. Its location in low latitudes facilitates a coverage with low-inclination satellites. Three satellites will be in geostationary orbit over the Indian Ocean. Missile targeting could be an important military application for the constellation.

The total cost of the project is expected to be ₹1,420 crore (US$221 million), with the cost of the ground segment being ₹300 crore(US$47 million). Each satellites costing ₹150 crore (US$23 million) and the PSLV-XL version rocket costs around ₹130 crore(US$20 million). The seven rockets would involve an outlay of around ₹910 crore (US$142 million. The NAVIC signal was released for evaluation in September 2014.

Accuracy:

The system is intended to provide an absolute position accuracy of better than 10 meters throughout Indian landmass and better than 20 meters in the Indian Ocean as well as a region extending approximately 1,500 km (930 mi) around India. The Space Applications Centre in 2017 said NAVIC will provide standard positioning service to all users with a position accuracy up to 5 m. The GPS, for comparison, had a position accuracy of 20–30 m. Unlike GPS which is dependent only on L-band, NAVIC has dual frequency (S and L bands). When low frequency signal travels through atmosphere, its velocity changes due to atmospheric disturbances. US banks on atmospheric model to assess frequency error and it has to update this model from time to time to assess the exact error. In India's case, the actual delay is assessed by measuring the difference in delay of dual frequency (S and L bands). Therefore, NavIC is not dependent on any model to find the frequency error and is more accurate than GPS.

Service and application:

It is designed to provide accurate position information service to users in India as well as the region extending up to 1500 km from its boundary, which is its primary service area. An Extended Service Area lies between primary service area and area enclosed by the rectangle from Latitude 30 deg South to 50 deg North, Longitude 30 deg East to 130 deg East.

IRNSS will provide two types of services, namely, Standard Positioning Service (SPS) which is provided to all the users and Restricted Service (RS), which is an encrypted service provided only to the authorised users. The IRNSS System is expected to provide a position accuracy of better than 20 m in the primary service area.

Some applications of IRNSS are:

Terrestrial, Aerial and Marine Navigation

Disaster Management

Vehicle tracking and fleet management

Integration with mobile phones

Precise Timing

Mapping and Geodetic data capture

Terrestrial navigation aid for hikers and travellers

Visual and voice navigation for driver.

About the satellite:

The  first satellite inaugurate this project of ISRO is IRNSS-1A ,which is launched on 1 July 2013.

The second satellite lRNSS-1B launched on 4 april 2014.

The 3^rd one is launched IRNSS-1C launched on 15 oct 14.

The forth is launched on 28 March 15 and its name is of-course IRNSS-1D.

The fifth was launched on 20 january 2015 .

The the last two were launched on 10 march and 28 april respectively.

The launched on eighth  navigation satellite of ISRO’s IRNSS-1H was unsuccessful. Which was launched on 31^st aug 2017 failed on its forth stage. Which was launched due to an atomic clock defecate on IRNSS-1A. This rubidium atomic clock are used to find the satellite position with an accuracy 0.5m.

Rubidium atomic clock

Now we talk about the IRNSS satellite .

It’s full name is Indian Regional Navigation satellite system . Though total launched satellite number is 8,one of these launched was failed ,so total number is now 7. Among the 7 ,3 are geostationary and 4 are geosynchronous .

IRNSS-1A:

It’s the first satellite of Indian Navigation project .

Orbit :Geosynchronous at 55 deg East longitude with 29deg inclination.

IRNSS-1A

Lift off mass:1425kg ,

Physical dimension :1.58m*1.50m*1.50m

Power  : Two solar panels generating 1660w,one lithium ion battery of 90 A hour capacity.

Propulsion: 440 newton liquid apogee motor,twelve 22 newton thruster .

Control system: Zero momentum system, orientation input from sun and star sensors and gyroscopes ,reaction wheels,magnetic torquers  and 22newton ,thrusters as actuators.

Mission life: Ten years.

IRNSS-1B:

IRNSS-1B

Orbit :Geosynchronous at 55 deg East longitude with 29deg inclination.

Lift off mass:1432kg ,

Physical dimension :1.58m*1.50m*1.50m

Mission life:10  years.

IRNSS-1C:

Orbit: Geostationary,at 83 degree East longitude.

Lift off mass:1425.4 kg,

Physical dimention:1.58m*1.50m*1.50m,

Power and propulsion details are same as above,

Mission life :10 years.

IRNSS-1D:
IRNSS-1D is the fourth navigation satellite of the seven satellites constituting the IRNSS space segment. Its predecessors, IRNSS-1A, 1B and 1C were launched by PSLV-C22, PSLV-C24 and PSLV-C26 in July 2013, April 2014 and October 2014 respectively. IRNSS-1D has a lift-off mass of 1425 kg. The configuration of IRNSS-1D is similar to that of IRNSS-1A, 1B and 1C. The satellite has been realised in less than four months after the launch of its predecessor.
The two solar panels of IRNSS-1D consisting of Ultra Triple Junction solar cells generate about 1660 Watts of electrical power. Sun and Star sensors as well as gyroscopes provide orientation reference for the satellite. Special thermal control schemes have been designed and implemented for some of the critical elements such as atomic clocks. The Attitude and Orbit Control System (AOCS) of IRNSS-1D maintains the satellite's orientation with the help of reaction wheels, magnetic torquers and thrusters. Its propulsion system consists of a Liquid Apogee Motor (LAM) and thrusters.
IRNSS-1D was launched into a sub Geosynchronous Transfer Orbit (sub GTO) with a 284 km perigee (nearest point to Earth) and 20,650 km apogee (farthest point to Earth) with an inclination of 19.2 deg with respect to the equatorial plane.
IRNSS-1E:
IRNSS-1E is the fifth navigation satellite of the seven satellites constituting the IRNSS space segment. Its predecessors, IRNSS-1A, 1B, 1C and 1D were launched by PSLV-C22, PSLV-C24, PSLV-C26 and PSLV-C27 in July 2013, April 2014, October 2014 and March 2015 respectively. IRNSS-1E has a lift-off mass of 1425 kg. The configuration of IRNSS-1E is similar to that of IRNSS-1A, 1B, 1C and 1D.  IRNSS -1E carries two types of payloads – navigation payload and ranging payload. The navigation payload of IRNSS-1E transmits navigation service signals to the users. This payload is operating in L5-band and S-band.

PSLV-C31/IRNSS-1E

 A highly accurate Rubidium atomic clock is part of the navigation payload of the satellite. The ranging payload of IRNSS-1E consists of a C-band transponder which facilitates accurate determination of the range of the satellite. IRNSS-1E also carries Corner Cube Retro Reflectors for laser ranging. PSLV-C31 Successfully launched IRNSS-1E  on January 20, 2016 at 09:31 Hrs (IST) from Satish Dhawan Space Centre SHAR (SDSC SHAR), Sriharikota, the spaceport of India.
IRNSS-1F:
IRNSS-1F is the sixth navigation satellite of the seven satellites constituting the Indian Regional Navigation Satellite System (IRNSS) space segment. Its predecessors, IRNSS-1A, 1B, 1C, 1D and 1E were successfully launched by PSLV-C22, PSLV-C24, PSLV-C26, PSLV-C27 and PSLV-C31 in July 2013, April 2014, October 2014, March 2015 and January 2016 respectively. All the five satellites are functioning satisfactorily from their designated orbital positions.
IRNSS-1F has a lift-off mass of 1425 kg. The configuration of IRNSS-1F is similar to that of IRNSS-1A, 1B, 1C, 1D and 1E. The two solar arrays of IRNSS-1F consisting of Ultra Triple Junction solar cells generate about 1660 Watts of electrical power. Sun and Star sensors as well as gyroscopes provide orientation reference for the satellite. Special thermal control schemes have been designed and implemented for some of the critical elements such as atomic clocks. The Attitude and Orbit Control System (AOCS) of IRNSS-1F maintains the satellite's orientation with the help of reaction wheels, magnetic torques and thrusters. Its propulsion system consists of a Liquid Apogee Motor (LAM) and thrusters.
IRNSS -1F carries two types of payloads – navigation payload and ranging payload. The navigation payload of IRNSS-1F transmits navigation service signals to the users. This payload is operating in L5-band and S-band. A highly accurate Rubidium atomic clock is part of the navigation payload of the satellite. The ranging payload of IRNSS-1F consists of a C-band transponder, which facilitates accurate determination of the range of the satellite. IRNSS-1F also carries Corner Cube Retro Reflectors for laser ranging.
IRNSS-1F was launched by PSLV-C32 into a sub Geosynchronous Transfer Orbit (sub GTO) on March 10, 2016 at 16:01 hrs (IST) from Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota
IRNSS-1G:
IRNSS-1G is the seventh navigation satellite of the seven satellites constituting the IRNSS space segment. Its predecessors, IRNSS-1A, 1B, 1C, 1D, 1E and 1F were launched by PSLV-C22, PSLV-C24, PSLV-C26, PSLV-C27, PSLV-C31 and PSLV-C32 in July 2013, April 2014, October 2014, March 2015, January 2016 and March 2016 respectively. Like all other IRNSS satellites, IRNSS-1G also has a lift-off mass of 1425 kg. The configuration of IRNSS-1G too is the same as IRNSS-1A, 1B, 1C, 1D, 1E and 1F.

Thank you for reading.

Li-Fi TECHNOLOGY

Li-Fi is a wireless optical networking technology that uses light-emitting diodes (LEDs) for data transmission.It works similar to Wi-Fi but it uses light signals. so we can say that , Li-Fi is light based Wi-Fi. and it uses light instead of radio waves to transmit information. 

  short history:

The term Li-Fi was coined by Professor Harald Hass , university of Edinburgh during a TED TALK in 2011. Hass presented light bulbs that could act as wireless routers. Subsequently, in 2012 , Hass set up company pureLiFi with the aim "to be the world leader in Visible Light communication technology".

How it works:

Data from the internet and the local network is used to modulate the intensity of the LED light source in a way undetectable to the human eye . The photo detector picks up the signal , which is converted back into a data stream and sent to the client . The client can communicate through its own LED output or over the existing network .

Reason for an alternate technology:

1.capacity

2.Efficientcy

3.Availability

4.Security

Li-Fi vs Wi-Fi:

1. On the basic of security Wi-Fi is not secured it can be hacked but the Li-Fi is secured than that of the Wi-Fi because it not easy to hacked.

2. On the basic of data transmission rate Wi-Fi is slower as it use radio waves but Li-Fi  is much faster as it uses visible light .

3. The range of the Wi-Fi is small in compare to that of the Li-Fi.

4.Wi-Fi can be used usually inside a building but the Li-Fi can be used anywhere, where light source is present .

5.On the basic of the cost we can say that Li-Fi is cheap in comparison to that of the Wi-Fi.

6.Working concept of the Wi-Fi is base on various topologies while working concept of the Li-Fi is based on direct binary data serving.

 Application of Li-Fi:

1. Smart lightening(street lamps)

2. Mobile connectivity 

3.We can use it in mines 

4. Aeroplanes 

5. underwater

6. In cars 

7. Hospitals

Advantages of Li-Fi:

*Radio waves are harmful for human being as they penetrate the body and may cause mutation . So Li-Fi is safe.

*It is very secure (no-body can hack it)since no signal penetration through walls.

*Tremendous data transfer rates.

*It works under water. its utility is limited by the distance light can penetrate water. Significant amounts of light do not penetrate further than 200 meters. Past 1000 meters, no light penetrates. , Also it can be used in aero planes, so it is benificial in many fields.

*Vehicles could communicate with one another via front and back lights to increase road safety. Also street lights and traffic signals could also provide information about current road situations.

Disadvantages of Li-Fi:

*These signals cannot penetrate walls. so the person needs wired bulb in that room also.

*Only works is there is direct line of sight between source and receiver.

Conclusion:

Every light bulbs can be converted into Li-Fi signal receptor to transfer data and we could proceed towards the cleaner, safer, greener and brighter future. It will also allow internet in those places where radio based wireless system isnot allowed . One thing for sure, Li-Fi is the future of mobile internet .