Top Five Historic Mars Landing Attempts

1-First Landing Attempt

World’s first ever lander attempt embarked by Soviet Union (Mars 2Mv-3 No.1). The lander was launched as a part of Soviet Mars Program in direction to touch the Red planet and labeled under Mars-Venus type of spacecraft. It is considered as fourth heaviest lander in the history of lander missions having 890 kilograms of mass. But as a consequence of launch vehicle malfunction, the lander never left low earth orbit and decayed from the next day of its launch. Some articles delineate that debris of this lander remained in LEO till 19 January 1963.

2-First artificial object on Mars

Mars 2 was the first human made object to touch the red planet. It was second landing attempt made by Russians as well as third heaviest lander having a mass of 1210 kilograms. One of the most incredible part of the mission is it carried a small 4.5 kilogram of Prop-M Rover that is far apart technology to think in 1970s. However, the lander made excellent entry into the Mars atmosphere and encountered module malfunction that results steep dive and crash into the surface. The small rover never had a chance to deploy.

3-First Successful Lander on Mars

Viking-1 – the most remarkable historic landing performed by Viking lander demonstrating the technological excellence near Chryse Planitia. The prime aim of the lander is to search for life and performing biological experiments on the Martian surface. This was the first U.S lander mission attempted towards Mars. Most interesting fact about Viking landers were, since its landing all the current landers employs Viking era technology for soft-landing. However the tests, the result declared negative.

4-Second Heaviest Lander

In the antiquity of lander attempts, second heaviest lander is Phobos landers strived towards Martian moon (Phobos-2600 kilograms) focusing to explore Martian moons and interplanetary environment between the Earth and Mars. But in Mars transit, both the landers encountered communication issue. As a consequence the mission endured unsuccessful.  

5-Heaviest Lander Mission

Mars 96 – top heaviest Mars lander having mass of 3159 kilograms launched as a part of Soviet Mars Program to investigate Mars. But the launcher malfunction made the spacecraft to strand in LEO and ultimately it destroyed in orbit during re-entry. Most interesting fact about this mission is, it carried 44 international instruments onboard and a surface station with small penetrator. It is considered as the first lander to carry more number of instruments.

Tags: Top Five Historic Mars Landing Attempts | Space Facts | Fornax Space Missions

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What is Satellite?

What is Satellite:

     A satellite is a artificial or man made object injected into space for particular applications. (Applications such as weather monitoring, astronomical observation, resource satellites, space explorations..,). The satellite is injected at a certain height from the earth surface which we call orbit. Man-made satellites are also called artificial satellites, this is because to distinguish from natural satellite (Earth's Moon).

Satellite orbiting Earth

What is difference between natural and artificial satellite?

Natural Satellite : A natural satellite is a astronomical object orbiting around particular planet. Example: The Moon which orbits around our earth is.

Artificial Satellite:  Artificial satellite is a human made object commanded or programmed to orbit around any astronomical object. Example: Mangalyaan Satellite around planet Mars and Chandrayaan-1 around Moon.

First Satellites of Nations in 20th Century:

1. Sputnik-1              Soviet Union
2. Explorer-1             United States
3. Asterix                   France
4. Osumi                    Japan
5. Dong Fang Hong  China
6. Prospero                United Kingdom
7. Rohini                    India
8. Ofeq-1                    Israel
9. Kosmos 2175         Russia
10. Strela                     Ukraine

First Satellites of Nations after 20th Century:

1. Omid                                           Iran
2. Kwangmyongsong 3 Unit-2      North Korea
3. Dove Pioneer, Lemur-2 (X2)     New Zealand

Types of Artificial Satellite:

• Earth observation satellites
• Navigational satellites
• Communication satellites
• Astronomical satellites
• Biosatellites
• Killer Satellites
• Crewed satellites (Spaceships)
• Nanosatellites
• Recovery satellites
• Reconnaissance satellites
• Weather satellites
• Deep space satellites
• Tether satellites
• Space stations

Satellite Subsystem:

• Structural system
• Telemetry system
• Power system
• Thermal control system
• Attitude control system
• Payloads
• Thruster control system

Origin of artificial satellites:

     In history of science, great scientist Sir.Issac Newton first published a paper on "Possibility of an artificial satellite". Similarly, in 1879 Edward Everett Hale depicted a satellite in his frictional writing. Later in 1903 Konstantin Tsiolkovsky mentioned satellite in his published paper "Exploring Space Using Jet Propulsion Devices"

Sputnik-1 First satellite in space 1957

     The space exploration began with the first successful launch of Sputnik-1 satellite of Soviet Union in 1957. It operated for 21 days in orbit and it's mission life ended in 26th October 1957. After the successful launch of Sputnik-1, many country started to launch their own satellites into space. Some of the first satellites of the nations are mentioned above.

Frequently asked questions:

How many satellites have been launched since launch of earth's first satellite?

     As per 2013 estimate by "Global experts Agree Action Needed on Space Debris" European Space Agency, more than 6,600 satellites from 40 countries around world have been launched. Out of these 6,600 only 1000 satellites were in operational.

Which is the oldest satellite in space?

     According to the statement of Wikipedia, Vanguard-1 is the oldest satellite in space, which is still orbiting the earth with its rocket's upper stage. It deactivated in 1964.

How many satellites are currently in active?

     As listed by Goddard Space Flight Center there are 2,271 satellites are currently active in orbit. Of these 1,324 satellites were from Soviet Russia and 658 satellites from United States of America.

Can we see satellites from Earth?

     Yes, we can see satellites from earth in the night sky when they pass overhead at a particular height. It can be seen at a place where there is no light and cloud free sky. It will look like a star moving across the sky. (Note: blinking of moving light is not star but a plane)

Which country has most satellites in space?

     Russia has 1,324 satellites, United States has 658 satellites, China has 177 satellites and Japan has 56 satellites. (Source: World Atlas)

How many satellites are owned by Google?

     As far 13 satellites are owned by Google and they are called GeoEye Satellites.

How much does it cost to built and launch a satellite?

     To built a satellite, it costs from $50 dollars to $500 million dollars. For launching it costs about $8000 dollars. (approximately)

Tags: What is Space? | Student Satellites | Space Telescopes | 

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What is Space?

What is Space?

Space-Universe

     Space is a zone or place extended over millions of kilometers above our earth's surface. It consists of millions of stars, planets, asteroids, comets, meteors, suns, galaxies and many solar system. In technical term, space is a vaccum. i.e sound cannot travel. It also have dark matters and dark energies that occupies 70 percent part of the universe. It also have black holes, supernova, binary stars, pulsars and giant gas nebulae.

Can life is possible in Space?

    Yes, life is possible. As per modern discoveries life is possible only in earth.Because it lies in the habitable zone and minimal distance from sun, so that it can maintain moderate temperature for life forms. But scientists predict that life can be possible in space beyond earth. Because the vast universe have multiple number of solar system and some planet may lie in the habitable zone like our earth.

Difficulties to live in space:

     Space is a blank area where we cannot breathe as there is no air and atmosphere. we cannot live in those blank space, because the pressure is very low as compared to the pressure of blood inside our body which results in burst of body and death. It does not have sufficient platform to stand and move our body parts, so we won't be stable in one place. we keep on moving towards any direction into the cosmos. It doesn't have plants to provide sufficient oxygen for individual human to breathe and there is no water to drink. One of the major problems is the exposure to radiation. Cosmic radiation comes from deep space can cause health problems like cancer and may leads to death.Similarly, there are many challenges for human beings to survive.

How universe is formed?

Universe

     The answer for "how the space and universe is formed?" is a still a hypothesis (unproven or may be proved in future) and a very difficult question to be explained by the scientists. The science of astronomy and astrophysics born in around 4th century at the time of Greek period. To answer this question, hundreds of scientists and astronomers are working day and night for proposing a model to explain the birth of universe. Finally in early 1927, one of the famous Belgian scientist of 20th century Georges Lemaitre first proposed an "expanding model of the universe" by which he formulated Hubble Law. Later, it became a key for the "Big Bang Theory" developed by Friedmann, Lemaitre, Robertson and Walker. 

What is Big-Bang Theory?

Big-Bang Theory model

     Big-Bang is a giant explosion of energetic particles and dark matter due to the action of gravity, which resulted in the formation of universe. The explosion include nuclear fusion and nuclear fission. Due to huge explosions matters started to expand and spread over the universe, these particles get collided  and combined to form stars, galaxies, solar systems and planets. Some of the small parts from the explosive became asteroids and comets. The formation took billions of years and the current age of the universe is about 4.6 billion years. Major contribution to this big-bang theory was made by American scientist "Stephen Hawking".

Black Holes:

Black Holes

     Black holes is otherwise called worm hole, which are formed by the collapsing of stars white dwarf. It have high gravitational field inside from which nothing can be escaped including light which travels at 300,000 km/sec. It is a mystery that what is inside the black hole? Research works are going on by several observatories around the world

Gravitational Waves:

Gravitational Waves

   Gravitational waves are ripples in space fabric. It was predicted by Albert Einstein in the last century but it was finally detected in 2017. It was detected by LIGO Observatory in Livingston. LIGO stands for Laser Interferometer Gravitational Observatory. The waves was discovered by three noble laureate's (Kip.S.Thorne et al, 2017). It was detected three times over two years in 2015 and 2016. Research papers were published about the discovery and detection of gravitational waves.

Planets and Moon:

Our Solar System

     Planets like Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and the dwarf Pluto were formed from the Sun. They were a part of burning sun. After few billion years, they started to cool shaping to a beautiful planet. The moons which are moving around every planets also formed from part of every planet. They process of geo-dynamic cooling prevailed for billion years. It made a change in the planetary surface of earth for the birth and origin of life.

Asteroids:

Asteroid

      Asteroids are nothing but the minor planets existing inside our solar system. The larger asteroids was called planetoids. They never grew to large one to become a planet. The are millions of asteroids revolving around the sun. They are densely gathered in a region called asteroid belt, which lie between planet Mars and Jupiter. Sometimes many small asteroids were used to fall on the surface of Earth and Mars, Jupiter was used to impacted by many asteroids from the asteroid belt.The first ever asteroid discovered was Ceres.

Comets:

Comets

   Comets are icy bodies coming from outer solar system. They are mostly made up of icy gases and used to come to our solar system after a certain cycle of time. They tend to melt and release gases when they pass close to our sun due to the action of heat. It melts completely and finally disappears. They are very popular and rare object in the sky to observe during life time. Some of the near earth comets were Encke's comet, Halley comet etc.. In our lifetime we can able to see both the comets mentioned earlier. We can see Encke comet in June 2020 and Halley's comet in July 2061 as expected by the astronomers.

Conclusion:

Imaginative Image of Earth and Asteroids

    Our space and universe is a beautiful creation ever made. Our knowledge about the universe is just 10% and still there are many things to know. Exploring and expanding the knowledge about the universe is a human nature. we will be having wonderful and mysterious discoveries in the future. Space is, that cannot be imagined simply in our brain.

Credits:
Image Credit : NASA
Text Credit: Team Spacexpress
Post Source: https://www.indianspacexpress.blogspot.in/

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Bow-Tie Nebula

NGC-40 (Bow-Tie Nebula) imaged by National Aeronautics Space Administration

New General Catalogue-40

     NGC-40 is a planetary nebula which was first discovered by famous astronomer William Herschel , during his observation into the dark sky on 25th November 1788. It was also called as Bow-Tie Nebula. He argued that the planetary nebula is composed of a dying star surrounded by hot gases. The star had already ejected its outer gas layer and the smaller star remains with a surface temperature of 50,000 degree Celsius. The temperature of the surrounding gases is about 10,000 degree Celsius which was heated by the radiation emitted from the star. Its width is about approx. 1 light year and it lie at a distance of 3500 light years away from our earth. Scientists predict that the star will fade away by leaving a small white dwarf after 30,000 years. The size of the white dwarf is equal to the size of the earth.

     This nebula is too far and it cannot be seen through our naked eye. It can be seen using extremely large telescopes and it can be located in the constellation of Cepheus. Its sister designations were Bow-Tie Nebula and Caldwell-2 as mentioned in SIMBAD Astronomical Database.

NGC-40 imaged by Hubble Space Telescope

More Information:

• Original full size image of NGC-40
• Bow-Tie Nebula - Wikipedia
• Download original 400x400 Hubble image of Planetary nebula NGC-40
• Chandra X-ray Observatory image of Bow-Tie Nebula

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Exoplanet

NASA Artist concept of exoplanet beyond our solar system

What is Exoplanet? 

     Exoplanet ( exo - means outer or outer solar system ) is a planet outside solar system which orbits a star. The concept of exoplanet was made in the early 1917, but the first confirmed scientific discovery was made in 1992. After that 3,710 planets were discovered outside our solar system including 621 planetary systems. These discoveries were made by High Accuracy Radio Velocity Planet Searcher, Kepler Space Telescope and several other ground based telescopes. It has been found that many planet lie in the habitable zone from their native star. Major discoveries was Proxima Centauri-b and Proxima Centauri closest star to our sun.

 Indian Observatory in Exoplanet Detection:

     The first involvement and report of existence of exoplanet was made by William Stephen Jacob at Madras Observatory controlled by English East India Company in 1855. Similarly in the year of 1890 another astronomer Thomas J.J.See from the University of Chicago stated the existence of 70-Ophiuchi system with 36-years of orbital period. Later, astronomer Forest Ray Moulton published a paper on three-body system with their orbital parameters.

 Detection Techniques:

• Direct imaging
• Gravitational microlensing
• Polarimetry
• Astrometry
• Radial velocity
• Pulsar timings variations
• Transit photometry etc..

 Most Amazing Discovery of exoplanet:

TRAPPIST-1 System :  
     
    NASA had made wonderful discovery of Trappist-1 system which is the best discovery of Hubble Space Telescope and NASA. Now, if we want to know more about the existence of life beyond the solar system, we need to know the age of the star. Young stars have frequent releases of high energy radiation called flares that can zap their planets. If a new planet is born then the orbit of that planet would be unstable.On the other hand, planets orbiting older stars have survived the spate of youthful flares, but have also been exposed to the ravages of stellar radiation for a longer period.

Now NASA's Scientists have a good estimate for the age of one of the most intriguing planetary systems discovered to the date called Trappist-1 System. A system of 7 earth seized planet orbiting a star which is nearly 40 million light years away from the earth. Researchers said that new study reveals that the star is too old between 5.4 to 9.8 billion years ago.

The seven wonders of TRAPPIST-1 were discovered using Transisting Planets and Infinitesimals Small Telescope (TRAPPIST) in Chile, Spitzer Space Telescope of NASA, and other ground based telescopes.

Trappist-1 is 13.7 billion years old in age than the universe and it is like a slow-burning candle that will shine for about 900 times longer than the current age of the universe.

In 2017, more than 139 exoplanets have been discovered.
Exoplanets discoeverd in 2017.

Tags: Exoplanet | Space facts

More Links:
 Top 5 high cited research papers on Exoplanet:

• Borucki, William J., et al. "Kepler planet-detection mission: introduction and first results." Science 327.5968 (2010): 977-980.
•  Charbonneau, David, et al. "Detection of planetary transits across a sun-like star." The Astrophysical Journal Letters 529.1 (1999): L45.
• Charbonneau, David, et al. "Detection of an extrasolar planet atmosphere." The Astrophysical Journal 568.1 (2002): 377. 
• PHASE, COMMISSIONING. "Setting new standards with HARPS." The Messenger 114 (2003): 20  
• Charbonneau, David, et al. "Detection of thermal emission from an extrasolar planet." The Astrophysical Journal 626.1 (2005): 523.

Credits:

 

Image Credit : NASA

Journal Credits : google scholar

Text References : Exoplanet ( wikipedia) retrived 2017 

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Proxima Centauri

Proxima Centauri Star. Image Source : wikipedia.org

Proxima Centauri:

     Proxima Centauri is the nearest star to our Earth and also near to the "Centaurus Star". It is located in the constellation of Centaurus which is nearly about 1.52 light years away from our Sun. It was first observed and discovered by Scottish astronomer Robert Innes in the Union Observatory in South Africa. It forms a third component for the Alpha Centauri Binary Star system. The orbital period of this star is 550,000 years.

     Mass of proxima centauri star is eighth of the mass of Sun and the density of the star is about 40 times larger than sun. Its changes in flare is due to the action of magnetic activity and the luminosity is very low, it cannot be clearly seen through our naked eye, because it is a flare star. The distance between the sun and proxima centauri is same as the distance between the sun and alpha centauri, this was calculated by Dutch astronomer Joan Voute (parallax method). In 2016, the European Southern observatory found that the star has a orbiting planet called Proxima-b and it is orbiting the star at a distance of 0.05 AU.

Proxima Centauri planetary system with proxima-b planet

     Proxima is a red dwarf, because it belongs to the Hertzsprung-Russell's M6 spectral class. It has a mean density of 1.411 x 10^3 kg/m^3 observed by Optical Interferometry Large Telescope in 2002. It has been observed by many observatories across the world. It is noted that its 85% of the energy is emitted as Infrared Radiation. The photometric variation of this star is 83.5 days as stated by a study in 1998. Like the sun, it is estimated that all the fuel of proxima will be consumed before the thermonuclear fusion comes to an end. The temperature measure is about 270,000,000 Kelvini and it is too hot emit x-ray. The estimated age of the star is 4.85 x 10^9 years. 

List of Observatories that observed Proxima Centauri:

• European Southern Observatory
• Union Observatory Jahannesburg
• Einstein Observatory
• XMM-Newton Observatory
• Chandra Observatory 
• Hubble Space Telescope 

Satellites which observed Proxima:

• EXOSAT
• ROSAT 

 Mostly cited Research Papers in referred journals:

1.  Anglada-Escudé, Guillem, et al. "A terrestrial planet candidate in a temperate orbit around Proxima Centauri." Nature 536.7617 (2016): 437-440.
2. Benedict, G. Fritz, et al. "Interferometric Astrometry of Proxima Centauri and Barnard's Star Using HUBBLE SPACE TELESCOPE Fine Guidance Sensor 3: Detection Limits for Substellar Companions." The Astronomical Journal 118.2 (1999): 1086.
3. Wood, Brian E., et al. "Observational estimates for the mass-loss rates of α Centauri and Proxima Centauri using Hubble Space Telescope Lyα spectra." The Astrophysical Journal Letters 547.1 (2001): L49.
    

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Light Year

What is light year?

      The term "light year" most commonly used to denote the distances between stars, galaxies, and from a point to far point of the universe. In astronomy, the familiar term to express distances is "Par-sec" which is equal to 3.26 light years.

Why it is light year?

     Because, one light year distance is equal to the distance traveled by light throughout a year. i.e; speed of light x year x 1 day in hours x 1 hour in minutes x 1 minute in seconds. It can be mathematically expressed as:

Distances of Some nearest object in light year:

    In the table below, distances of some nearest object from earth measured in light year.

* Gliese 581 Red Dwarf

** It is A0620-00 the nearest black hole i.e; 3000 light years away from Earth

Importance:

    The unit of distances between stars and galaxies are measured in light year. It have been in practical use since 1984.But now the modern astronomers use parsec , light years also popularly used to express distances between interstellar and intergalactic distance.

History:

    The usage of light year came into existence when famous astronomer Friedrich Bessel in 1838 measured the distance between a star and earth was calculated. The star was called 61-Cygni.

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Gravitational Waves

Gravitational Waves from two neutron stars. Image Credit : LIGO

     Gravitational waves are the ripples in the space-time fabric, which are caused by the violent and energetic process of the universe. These waves are produced from the collision of neutron stars, massive acclerating black holes, stellar cores, supernovas, coalescing neutron and white dwarfs. Famous physicist Albert Einstein predicted the existence of gravitational waves in 1916, he proved by his mathematical expression. After 20 years of prediction of gravitational waves, scientists detected the gravitational waves from binary pulsar star in 1974. 

Detection:

     In 1974, two astronomers working at Arecibo Radio Observatory in Puerto Rico discovered a binary pulsar two extremely dense and heavy stars in orbit around each other. This was similar to the theory of relativity in which the body radiates gravitational waves from the source in a space-time fabric. The study had continued for 40 years about the binary pulsar star. In 14 September 2015, Laser Interferometer Gravitational Wave Observatory (LIGO), first time detected the distortion in the space-time fabric. the distortion was due to the collision of fast rotating black holes nearly 1.3 billion light years away. LIGO made a huge achievement after detecting the waves. When it was detected, the sound was like a "bird chirp".

Need to detect Gravitational Wave:

     Gravitational wave can only be detected by LIGO observatory, because it was designed in such a way that it can detect any small or tiny distortion in the fabric of space time. Similar to the discovery of gravity, the gravitational wave will change the view of space science and will help us to understand the origin of the universe in a effective manner.

Data in gravitaional wave:

     Astronomers and data scientists stated that gravitational waves are not like electromagnetic radiation, it is quite different from the EM wave. It carry information and data of cosmic object in space-time, and it travel at a speed of light in the universe. They interaction between the dark matter and gravitational wave in space is very weak.

Souces of waves:

• Neutron stars
• Binary neutron stars
• Binary black holes

LIGO:

LIGO - Gravitational Observatory, Hanford, USA

     LIGO stands for Laser Interferometer Gravitational Wave Observatory is a observatory established in Hanforn and Livingston in the shape of "L". They are of 4km x 4km of length, It was constructed to act as antenna for the detection of gravitational waves.It can detect waves at a wavelength of 30 Hz to 7 kHz.

Observatories and Collaborations:

     Many scientists and engineers are involved in the detction of  gravitational wave outside the Hanford,Livingston,Caltech and MIT. They are all part of scientific collaboration of LIGO.

• LIGO's Dual detectors
• LIGO-India (planned joint work with India)
• Virgo, GEO and KAGRA   

More Information:

• LIGO - Caltech
• LIGO -  Hanford Observatory
• LIGO - Livingston Observatory
• LIGO - MIT
• Press Releases - LIGO - Gravitational wave detection: 
• Detection on 16 October 2017
• Detection on 27 September 2017
• Detection on 01 June 2017
• Detection on 15 June 2016
• Detection on 11 February 2016 

Research Papers on Gravitational Wave Detection:

1.  Eberle, Tobias, et al. "Quantum enhancement of the zero-area Sagnac interferometer topology for gravitational wave detection." Physical review letters 104.25 (2010): 251102.
2.  Harry, Gregory M., and LIGO Scientific Collaboration. "Advanced LIGO: the next generation of gravitational wave detectors." Classical and Quantum Gravity 27.8 (2010): 084006.
3.  Abbott, B. P., et al. "LIGO: the laser interferometer gravitational-wave observatory." Reports on Progress in Physics 72.7 (2009): 076901.
4. Abadie, Jea, et al. "Predictions for the rates of compact binary coalescences observable by ground-based gravitational-wave detectors." Classical and Quantum Gravity 27.17 (2010): 173001. 
     

Credits:

  

Image Credit : LIGO

Journal Credit : Google Scholar

 

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Dark Matter and Dark Energy

Dark matter and dark energy universe Image Credit : NASA's Hubble space telescope

     Dark matter and dark energy is a hypothesized theory which was widely accepted around the world. In the field of astronomy and cosmology, dark energy is a unknown form of energy which widely distributed in the universe. This dark matter and dark energy is responsible for the brief expansion and acceleration of the universe. It was mostly accepted hypothesis since 1990. According to the modern concept of cosmology, the total universe constitutes 68.3% percent of dark matter and the remaining are neutrinos and photons. It is very difficult for the scientist in defining and explaining the dark matter by experiments, however it may be proved in upcoming generations.

Discovery:

     Most familiar scientists Alan Guth and Alexei Starobinsky were the one who firstly proposed the dark matter in early 1980 and that could drive the inflation of universe. (Infilation is nothing but , some kind of repulsive force which resulted in expansion of the universe after the great Big-Bang (Giant explosion of dark matter to form universe). It is very interesting that, big-bang took with higher density(sum of dark matter and energy) of universe, it was likely to end within a second.

Hubble Constant:

    During 1980s, when they proposed the theory, they found that 95% of universe consist of cold dark matter and 5% of ordinary matter which is nothing, but the baryons. The discovery led to many difficulties in defining to the value acquired by the Hubble (Hubble constant). This difficulties became very stronger after the COBE Spacecraft of 1992 discovered the anisotropy. The first evidence of dark matter was observed from a supernova explosion in 1998, this was observed by Riess and Perlmutter.

Evidences of dark matter:

     Scientists provided indirect evidences for the existence of dark matter from the independent sources

1. By measuring the distances and relating it to the redshift
2. Theoretically, it is not a dark matter to form flattened universe
3.  By measuring the wave patterns and mass density form various sources of the universe

First Observed Supernova:

     In the year 1998, a team called Hihg-Z Supernova Search Team published their observation on Type-A Supernova. In 1999, Nobel Prize in Physics was awarded to Saul Perlmutter, Brian P.Schmidt and Adam G.Riess for their discovery suggesting the expansion and acceleration of the universe (Supernova Cosmology Project).

Research Papers Published in the high profile referred journals:

      High rated and cited research paper on Dark Matter in google scholar from 1980 to 2000.

1) Smith, P. F., & Lewin, J. D. (1990). Dark matter detection. Physics Reports, 187(5), 203-280.
2) Freese, K., Frieman, J., & Gould, A. (1988). Signal modulation in cold-dark-matter detection. Physical Review D, 37(12), 3388.
3)  Savage, Christopher, et al. "Compatibility of DAMA/LIBRA dark matter detection with other searches." Journal of Cosmology and Astroparticle Physics 2009.04 (2009): 010.
4) Munoz, Carlos. "Dark matter detection in the light of recent experimental results." International Journal of Modern Physics A 19.19 (2004): 3093-3169.

5) Spiro, Michel. "Dark matter." Nuclear Physics B-Proceedings Supplements 43.1-3 (1995): 100-107.

Credits:

Journal credits : Google Scholar 
Image Credit : NASA's Hubble Space Telescope

Tags: dark matter | space facts | universe | relativity 

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Mars missions timeline

Introduction:

     Since earlier times scientists and explorers are very interested in exploring outer planets and in search for life beyond earth. when it comes to "make survival of human on other planet" the only possibility of life beyond earth on another planet is "Mars". It is because Mars lies after the habitable zone (i.e Earth) and it may provide suitable temperature for the formation of life on its surface. Recently, scientists have discovered the ice and water under the soil surface ( Curiosity Rover discovery). From 1960 to recent times, we have been exploring Mars by several missions. This mission includes orbiters, landers, rovers and penetrators. 

Orbiter:

     An orbiter is a robotic spacecraft that explores another planet by orbiting around the planet in its trajectory. It operates by the command programmed by the scientists and further responses according to the commanding signal received from the earth station. It uses its solar panels to power and have several instruments to measure various parameters. 

Lander:

     Similarly, a lander also a robotic spacecraft having arms and cameras, that comes to rest or lands on the surface of Mars. It performs various experiments as programmed by the scientists. It uses its arm to take and analyse the soil composition, its cameras used to image the surface and colour of the soil surface.

Rover:

    A Rover is a moving spacecraft having wheels, example - curiosity rover. It moves on the surface of Mars and performs several experiments. It chooses different location to perform drill practices and soil analysis. It moves very slow as compared to the earth vehicles.

Mars Mission Timeline:

Flybys:-

• Mars 1M No.1
• Mars 1M No.2
• 2MV-4 No.1
• 2MV-4 No.2
• Mariner-3
• Mariner-4
• Zond-2
• Mariner-6
• Mariner-7
• Mars-6
• Mars-7

Orbiters:-

• 2M No.521
• 2M No.522
• Mariner-8
• Kosmos-419
• Mars-2
• Mars-3
• Mariner-9
• Mars-4
• Mars-5
• Viking-1-orbiter
• Viking-2-orbiter
• Phobos-1
• Phobos-2
• Mars Observer
• Mars Global Surveyor
• Mars-96
• Nizomi
• Mars Climate Orbiter
• Mars Odyssey
• Mars Express
• Mars Reconnaissance Orbiter
• Fobos-Grunt
• Yinghuo-1
• Mars Orbiter Mission
• MAVEN
• ExoMars Trace Gas Orbiter

Landers:-

• 2MV3-No.1
• Mars-2 
• Mars-3 
• Mars-6 
• Mars-7
• Viking-2
• Phobos-1
• Phobos-2
• Mars Pathfinder
• Mars Polar Lander
• Beagle-2
• Phoenix
• Schiaparelli

Penetrators:-

• Mars-96
• Deep Space-2

Rovers:-

• Prop-M-rover
• Sojourner
• Spirit
• Opportunity
• Curiosity

Gravity assist probes:-

• Rosetta
• Dawn

Active Mars Missions:

• Mars Odyssey
• Mars Express
• Opportunity Rover
• Mars Reconnaissance Orbiter
• Curiosity Rover
• Mars Orbiter Mission
• MAVEN
• ExoMars Trace Gas Orbiter

Conclusion:

     Out of several missions, only 8 missions are currently active in exploring Mars. Curiosity rover discoveries changes the view of Mars since its launch. Space agencies have many future proposals for mars missions. One of the space agency called space-x is currently working on Human Mars Mission which is a part of Making Life Multiplanetary. 

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