Tuesday, 13 August 2013

EXOPLANETS, WHERE IN THE UNIVERSE ARE YOU?


Exoplanets, where are you?The Milky Way Galaxy, mosaic composition as viewed on a clear night from Cerro Paranal, Chile. European Southern Observatory (ESO), 2009.

The Milky Way, our Galaxy, is thought to be 13.7 billion years old and contains around 300 billion of stars. Could somewhere out there be a planetary system similar to ours? Perhaps a planet that followed the same evolutionary path? Where to look for it/them?

If life begun by a coincidental assembly of elements in a favourable environment, there has been enough time and plenty of opportunities for similar circumstances to take place anywhere else in our galaxy or further away.

Steven Hawking’s thoughts about search for exoplanets and life in the universe.“Our solar system was formed about ten billion years after the Big Bang, from gas contaminated with the remains of earlier stars. The Earth was formed largely out of the heavier elements, including carbon and oxygen. Somehow, some of these atoms came to be arranged in the form of molecules of DNA.

We do not know how DNA molecules first appeared. The chances against a DNA molecule arising by random fluctuations are very small. Some people have therefore suggested that life came to Earth from elsewhere, and that there are seeds of life floating around in the galaxy. However, it seems unlikely that DNA could survive for long in the radiation in space. And even if it could, it would not really help explain the origin of life, because the time available since the formation of carbon is only just over double the age of the Earth.

One possibility is that the formation of something like DNA, which could reproduce itself, is extremely unlikely. However, in a universe with a very large, or infinite, number of stars, one would expect it to occur in a few stellar systems, but they would be very widely separated” (Hawking, S. No date).

It is accepted by many astrophysicists that there is a high probability of there being life elsewhere in the universe, if not on other planets or on moons within our own solar system (deGrasse Tyson, N. No date). Astronomers are constantly looking for evidence of planetary arrangements similar to ours because they might have provided the opportunity for the development of life.

Planets found outside our Solar System are called Exoplanets or Extra Solar Planets, thought to revolve around their own star. Only the star is directly visible from Earth because it produces light. Planets illuminated by their star are too small and dim to be visible. Their presence is only deducted by indirect methods, which have improved with advances in astronomy.

One of the first reports of the discovery of planets orbiting a star (pulsar PSR B1257+12) was made by radio astronomers Wolszczan and Frail in 1992. Later, in 1995, a planet was found orbiting a star (51 Pegasi) by Mayor and Queloz. This time the planet had a 4.2-day orbital period and seemed to be too close to the star to have earth-like temperatures. Since then, other similar arrangements were described and those planets were commonly named “Hot Jupiters” or “Roaster Planets” because only giants are large enough to be detected.

In the last 18 years, 859 exoplanets were identified, including 128 multiple planetary systems. The majority of them falling into the category of Hot Jupiters. Stellar imaging technology is still unable to detect smaller and dimmer planets.

METHODS OF DETECTION

The first method of detection is Radial Velocity, which relies on the detection of changes in spectral characteristics of the star as it moves away and towards us. These changes are presumed to be a response to the gravitational pull of the giant exoplanet. This deduction method cannot apply to smaller planets with larger orbits as they would hardly cause any change on the star they are orbiting.

Photometric Transit detection method for large planets orbiting a star, also known as  Hot Jupiters.The second method of detection is Photometric Transit, where changes in brightness of the star are assumed to be caused by a large planet crossing between the star and our observation point. The larger the planet, the more it will obscure the star as it travels in front of it, an effect also known as Primary Eclipse. A Secondary Eclipse occurs when the planet’s signal disappears as it travels behind the star (Harvey, S. 2011). This is also an indirect method and its biggest problem is that it only works if the plane of the planetary orbit is close to our observation line of sight, which is thought to account only for 10% of the cases. Other factors affecting luminosity result in around 35% of false-positive reports.

Even combining both methods, it may take the better part of this century to find the perfect alignment to confirm at least 3 orbits.

SEARCH EFFORTS AND NEW TECHNOLOGIES

SETI, the Search for Extraterrestrial Intelligence Institute.The Search for Extraterrestrial Intelligence Institute (SETI) has been looking for evidence of life in the universe since 1984. Although it has not yet confirmed a signal from an alien civilization, optimists say that it is only a matter of time. The SETI Institute is comprised by three centres, the Centre for SETI Research, the Carl Sagan Centre for the Study of Life in the Universe and the Centre for Education and Public Outreach.

NASA is also looking further away than our solar system, they have plans to build a telescope called the Terrestrial Planet Finder to search for Earth-like planets (Achenbach, J. No date).

Trajectory of the 8 satellites proposed to place into orbit by the Stellar Observation Network Group (SONG).Among the new efforts to detect minute changes in spectral characteristics of stars, is that proposed by Danish astronomers from the Stellar Observation Network Group (SONG) at Aarhus University. The plan is to build a network of 8 robotic telescopes orbiting our planet in 2 rings: one in the northern and another one in the southern hemisphere. Thanks to their separation, data collected from their different points of view would make it possible to detect positional changes and optical effects like Microlensing, which occurs as the light from a star is deviated by the gravitational field of a nearby object like a planet. Although the planet cannot be seen, its presence can be deducted by the deviation of light it produces when it is in close alignment to its star.

Other technological developments involve advances in telescope light sensors with increasing resolution and reduced noise at low light levels. Coupled with high speed acquisition of images, modern devices are essentially photon counting as most frames in dark areas will contain zero photons.

La Silla observatory in the Atacama desert, Chile, houses some of the largest optical telescopes. The 2400m high site has minimal light pollution.An example of new technology is the Electron Multiplying Charge-Coupled Device (EMCCD), a light sensor recently installed on the 1.54m Danish Telescope at “La Silla” Observatory in Chile. This famous site offers minimal light pollution thanks to its high altitude at 2400m and its location, surrounded by the Atacama desert, far from urban areas. The new light sensor technology is also being adopted by the Stellar Observation Network Group (SONG) for their observatories: “Teide” in Tenerife and “Qinhai” on the Tibetan Plateau.

By January 2013, from less than 1000 exoplanets discovered, 4 planets ranging between 1.5 and 2 times the size of Earth have been found to be orbiting a star similar to our own.

The closest exoplanet under scrutiny is Alpha Centauri Bb. Having a mass similar to Earth’s, it is thought to be in orbit around the star Alpha Centauri B, located 4.37 light-years away. The planet was discovered using Doppler Spectroscopy in 2008, and after more than 450 observations and data analysis to remove sources of error, scientists were able to announce the finding in October 2012. In June 2013, other scientists found evidence of activity noise in the data, which played against the confirmation of the discovery (Hatzes, A. 2013). The case is therefore inconclusive and requires further research.

THE POSSIBILITY OF LIFE

Behind all these efforts is the idea of the possibility of life existing somewhere in the universe. If life evolved by chance on this planet, why wouldn’t it have also evolved somewhere else? Given the vast number of planetary systems being found only in our vicinity and the time that elapsed since the creation of those systems, it would be too egocentric to think that our situation is unique.

Scientist use our own evolution and the changes happening to our society to predict what could happen in the future. A path that could be applicable to life forms developing in similar systems somewhere else in the universe.

One of those scientists is Astrophysicist Dr Michio Kaku, who has dedicated part of his life to the promotion of science, making it accessible to the public and expressing his view of the future of humanity.

In his book “Physics of the Future: How scientists will shape human destiny and our daily lives by the year 2100,” Dr Kaku predicts changes from the perspective of an “insider” who, after interviewing more than 300 scientist, has first-hand look at novelty products. The prototypes of all technologies already exist, giving his forecast a solid base.

“We are witnessing the birth of a new era, in which we will become masters of nature as our civilisation evolves to type-1” (Kaku, 2011).

The following video shows Dr Kaku introducing his vision in 2011, as he mentions the search for exoplanets and where we fit in his theoretical universal ranking of civilisations.




UNPRECEDENTED PROGRESS

Technology is advancing at an unprecedented rate. In the field of computing, a modern pocket mobile device has thousands of more calculation power than the IBM 1401, one of the most powerful computers built only 50 years ago, which occupied an entire room and weighted 4 tons.
At a price of £1 million, that computer was a distant relative of our current £50 mobile devices.

With ever increasing numbers of research centres, advances in technology are leading the way of society. We can hardly keep up with the pace of change. By the time we learn how to use our new devices, they have already become obsolete. The same goes for the search of exoplanets, improvements in resolution will increase the chances of finding hundreds or perhaps thousands of planets with the potential of sustaining life.


References


§ Achenbach, J (No date) "Life Beyond Earth." National Geographic Magazine [Online]. Available here. (Accessed: 02 August 2013).
§ "Alpha Centauri Bb" (2013). Wikipedia. [Online]. Available here. (Accessed: 13 August 2013).
§ deGrasse Tyson, N (No date) "The Search for Life in the Universe." NASA's Astrobiology Magazine [Online]. Available here. (Accessed: 02 August 2013).
§ "Extrasolar Planet" (2013). Wikipedia. [Online]. Available here. (Accessed: 13 August 2013).
§ Harvey, S (2011) "The Exotic Atmospheres of Hot Jupiter-like Planets." NASA's Solar System Exploration [Online]. Available here. (Accessed: 09 August 2013).
§ Harpsoe, K (2013) "The search for Earth-like Exoplanets." Labnews magazine, March, pp 24-25.
§ Hatzes, A (2013) "Radial Velocity Detection of Earth-mass Planets in the Presence of Activity Noise: The Case of Alpha Centauri Bb." The Astrophysical Journal at Cornell University Library [Online]. Available here. (Accessed: 13 September 2013).
§ Hawking, S (No date) "Life in the Universe." [Online]. Available here. (Accessed: 02 August 2013).
§ Kaku, M (2011) Physics of the Future: How scientists will shape human destiny and our daily lives by the year 2100. 1st ed. New York: Doubleday.
§ "Milky Way" (2013). Wikipedia. [Online]. Available here. (Accessed: 02 August 2013).
§ "SETI 101" (2013). SETI Institute. [Online]. Available here. (Accessed: 02 August 2013).



Images


§ All images edited by ren@rt. Source: NASA, Scribd, SETI, YouTube and others.

Monday, 6 August 2012

MAIL FROM MARS!



Polaroid from Curiosity, the Mars Science Laboratory robotic rover, that landed successfully on Mars on 6th August 2012. NASA/JPL.Polaroid from Curiosity, the Mars Science Laboratory robotic rover, that landed successfully on Mars on 6th August 2012. NASA/JPL.

‘Nuf said !

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D-day on Mars!

The control room at Jet Propulsion Laboratory (JPL) in Pasadena, Califormia came alive as the Entry, Descent and Landing team or “blue shirts” monitored the progress of Curiosity rover, as she landed on Mars. The atmosphere was electric, charged with suspense.

Adam Steltzner could be seen walking up and down the floor, while the rest of his team were sitting on the edge of their seats. Meanwhile, the clocks were counting down the seconds and the cold, monotonous voice of the narrator described the events visualised on the screens.

Curiosity MSL lands on Mars. Entry, Descent and Landing (EDL) team in blue shirts. Laptop table. Control room at JPL, 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Entry, Descent and Landing (EDL) team in blue shirts. Nervous wait. Control room at JPL, 6 August 2012. NASA/JPL.
Curiosity MSL lands on Mars. Entry, Descent and Landing (EDL) team in blue shirts. Charles Elachi, Director of JPL and other bosses waiting for news. Control room at JPL, 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Entry, Descent and Landing (EDL) team in blue shirts. Adam Stelzner, Lead of EDL waiting for news. Control room at JPL, 6 August 2012. NASA/JPL.
Curiosity MSL lands on Mars. Computer simulation of entry into Martian atmosphere. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Computer simulation of emergence from upper atmosphere. Landing site on view. 6 August 2012. NASA/JPL.

The first applause came when Curiosity entered the atmosphere. A few minutes later, the team exploded again as the confirmation of a successful parachute opening arrived. As calculated, the Mars Reconnaissance Orbiter (MRO) was passing over Curiosity at that precise moment and took pictures of the parachute from above.

Curiosity MSL lands on Mars. Computer simulation of deployment of the supersonic parachute. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Entry, Descent and Landing (EDL) team in blue shirts. Rejoice after parachute deployment. Control room at JPL, 6 August 2012. NASA/JPL.
Curiosity MSL lands on Mars. Computer simulation of Mars Reconnaissance Orbiter (MRO) looking at the supersonic parachute stage. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Pictures sent by Mars Reconnaissance Orbiter (MRO). View of Curiosity and her supersonic parachute. 6 August 2012. NASA/JPL.

Moments later, when the free-fall of the spacecraft was under control, the announcement of Powered Flight was heard, which implied a separation from the parachute. Shortly after another burst of cheers came when the crane separated the rover from the jet-pack.

Curiosity MSL lands on Mars. Adam Stelzner, Lead of EDL in action. Control room at JPL, 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Sky crane stage after the descent stage slows down the fall to a gentle speed. 6 August 2012. NASA/JPL.

But all that cheering was nothing, compared to the explosion of joy with happy laughs, fists in the air, high-fives and emotional embraces, mixed with the occasional sigh of relief that followed the announcement of MSL Touchdown.

Curiosity MSL lands on Mars. Computer simulation model of approximate position of Curiosity landing site. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Pictures sent by Mars Reconnaissance Orbiter (MRO) of Curiosity's landing position. 6 August 2012. NASA/JPL.
Curiosity MSL lands on Mars. Entry, Descent and Landing (EDL) team in blue shirts. Celebrate touchdown of Curiosity on Mars, hi-fives. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Entry, Descent and Landing (EDL) team in blue shirts. Celebrate touchdown of Curiosity on Mars, fist in the air. 6 August 2012. NASA/JPL.
Curiosity MSL lands on Mars. Entry, Descent and Landing (EDL) team in blue shirts. Adam Stelzner congratulates EDL colleagues. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Entry, Descent and Landing (EDL) team in blue shirts. emotional embraces. 6 August 2012. NASA/JPL.

Eight years of hard work of scientific and technical teams in the US and other countries were finally rewarded with the best news they could hear. The proof of their dedication arrived a few minutes later with the first picture from the cameras mounted on Curiosity, which cemented their irrefutable success.

Curiosity MSL lands on Mars. The first thumbnail from Mars, sent by the cameras on-board Curiosity. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Entry, Descent and Landing (EDL) team in blue shirts celebrate the first picture from Curiosity. 6 August 2012. NASA/JPL.

The first picture showed the Martian horizon as seen from inside the Gale Crater. Just a few minutes later, a second image showed one of the wheels of the rover, standing proud on Martian ground.

Although some dust particles appeared on the lens and in front of the camera at first, the view cleared up soon to allow for more pictures from the front and rear cameras.

Curiosity MSL lands on Mars. Curiosity camera showing the shadow of the rover on Martian ground. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Curiosity camera showing her rear-left wheel firmly on Martian ground. 6 August 2012. NASA/JPL.
Curiosity MSL lands on Mars. Curiosity camera showing the shadow of the rover and dust collection. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Curiosity camera showing her rear-left wheel on Martian ground. 6 August 2012. NASA/JPL.
Curiosity MSL lands on Mars. Emotional embraces of happiness after the first pictures confirm touchdown and functional status of Curiosity on Mars. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Adam Stelzner embraces team members after the first pictures confirm touchdown on Mars. 6 August 2012. NASA/JPL.
Curiosity MSL lands on Mars. Entry, Descent and Landing (EDL) team in blue shirts celebrate touchdown on Mars. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Entry, Descent and Landing (EDL) team in blue shirts celebrate touchdown on Mars. 6 August 2012. NASA/JPL.

The celebrations and congratulations continued and extended to the press conference, where program leaders had the chance to shake hands with everyone from their team and journalist from all over the world had the opportunity to ask questions.

Curiosity MSL lands on Mars. Charlie Bolden, NASA Administrator comments on touchdown on Mars. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Charles Elachi, Director of JPL comments on touchdown on Mars. 6 August 2012. NASA/JPL.
Curiosity MSL lands on Mars. Press conference post touch-down on Mars. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Press conference post touch-down on Mars, Procession of Entry, Descent and Landing (EDL) team to salute the directors. 6 August 2012. NASA/JPL.
Curiosity MSL lands on Mars. Peter Theisinger and Adam Stelzner shake hands of team members of the Entry, Descent and Landing (EDL). 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Richard Cook, Peter Theisinger and Adam Stelzner shake hands of team members of the Entry, Descent and Landing (EDL). 6 August 2012. NASA/JPL.

Finally, the Entry, Descent and Landing team, in charge of getting the rover to Mars, handed over control of the MSL mission to the Surface Operations Team. From now, they will control and communicate with Curiosity during the duration of the mission, which for the next 2 years will be dedicated to scientific developments.

The celebrations and congratulations continued and extended to the press conference, where program leaders had the chance to shake hands with everyone from their team and journalist from all over the world had the opportunity to ask questions.

Curiosity MSL lands on Mars. Press conference post touch-down on Mars. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Richard Cook and Adam Stelzner at the press converence post-landing on Mars. 6 August 2012. NASA/JPL.
Curiosity MSL lands on Mars. Adam Stelzner explains the successful landing at the press conference. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Entry, Descent and Landing (EDL) team wearing blue enjoy their success at the press conference post-landing on Mars. 6 August 2012. NASA/JPL.
Curiosity MSL lands on Mars. Adam Stelzner and John Grotzinger at the press conference post-landing on Mars. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. John Grotzinger, Chief of Scientists at JPL at the press conference post-landing on Mars. 6 August 2012. NASA/JPL.

The lifespan of MSL is guaranteed for 2 years but designed for 6. Like previous missions it will most likely operate for much longer. Now that Curiosity is on Mars, the most exciting chapter of her history is about to unfold.

Curiosity MSL lands on Mars. Victorious JPL team at the press conference post-landing on Mars. 6 August 2012. NASA/JPL.Curiosity MSL lands on Mars. Victorious JPL team at the press conference post-landing on Mars. 6 August 2012. NASA/JPL.

Time for science to take over and let discoveries begin!