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Posts Tagged ‘Extraterrestrial life

The ChemCam system of Curiosity rover

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Light on Mars? Curiosity rover to fire ‘million bulb torch’ at planet’s surface to see if it’s habitable
The Mars lander will fire a laser beam with the energy of a million lightbulbs at the surface of the red planet to see whether or not it could have supported life.
The international team of space explorers that launched the Mars Science Laboratory is relying on the instrument to look for biological signs on the distant world.
The ChemCam will fire a powerful laser pulse, vaporising some Mars dust and examining the spectrum of light shining through it.

The light fantastic: The ChemCam system uses a laser to take samples from as far as 23 feet away from the Curiosity rover

The robust system is one of 10 instruments mounted on the mission’s rover vehicle, named Curiosity.
When ChemCam fires its extremely powerful laser pulse, it will vaporize an area the size of a pinhead.
The system’s telescope will peer at the flash of glowing plasma created by the vaporized material and record the colors of light contained within it.

These spectral colors will then be interpreted by a spectrometer, enabling scientists to determine the elemental composition of the vaporised material.

ChemCam can deliver multiple pulses in extremely rapid succession to a single area or quickly zap multiple areas, providing researchers with great versatility for sampling the surface of the planet.

‘ChemCam is designed to look for lighter elements such as carbon, nitrogen, and oxygen, all of which are crucial for life,’ said Roger Wiens, principal investigator of the MSL mission’s ChemCam team.
‘The system can provide immediate, unambiguous detection of water from frost or other sources on the surface as well as carbon – a basic building block of life as well as a possible by-product of life. This makes the ChemCam a vital component of Curiosity’s mission.’
The system looks at the entire visible spectrum as well as portions on either side (the infrared and ultraviolet), enabling it to see any element on the periodic table. ChemCam can zap an area about 23ft away from the rover vehicle.
The system relies on a technology primarily developed at Los Alamos called laser-induced breakdown spectroscopy (LIBS).
At the heart of the technology is an infrared laser – invisible to the naked eye – that focuses more than a million watts of power onto a tiny area for five-billionths of a second.
LIBS has successfully been used on Earth to determine the composition of objects within extreme environments such as inside nuclear reactors and on the sea floor.
The Mars Science Laboratory is the technology’s first extraterrestrial use.
The French national space agency, Centre National d’Études Spatiales, and France provided ChemCam’s laser and telescope. LANL supplied ChemCam’s spectrometers and data processors, and leads the overall investigation.
Once the rover lands on Mars, LANL operations specialists will control the instrument.

Los Alamos also has roles in other aspects of the Mars Science Laboratory. Dave Vaniman of LANL’s Earth and Environmental Sciences Division is deputy leader of another instrument called CheMin, which uses X-ray diffraction to determine the composition of mineral samples collected and dropped into a funnel on the Curiosity rover.
Los Alamos also provided the plutonium canisters to power and heat to the rover, an effort which is the fruit of the expertise of nearly 50 researchers and technicians.
The power sources, called radioisotope thermoelectric generators (RTGs), will give Curiosity several times as much electricity as past rovers, and are needed for the much larger, more advanced payload on Curiosity.
Nasa launched the Mars Science Laboratory on Saturday into a cloudy Florida sky.
here was no sign of life, but scientists hope Curiosity’s more sophisticated equipment will reveal more.
It will be ‘the largest and most complex piece of equipment ever placed on the surface of another planet’, said Doug McCuistion, director of Nasa’s Mars exploration programme.
The rover is expected to land on Mars on August 5, 2012, after travelling nearly 354million miles from our planet.
One of the chief tasks of the $2.5billion mission will be to discover the source of the methane gas scientists have detected in the Martian air.
Curiosity will roam the planet’s surface for about 98 weeks, or the period of one Martian year.
Read more: http://www.dailymail.co.uk

Read also: Mars mission will use million light bulb torch to look for life

Written by physicsgg

November 29, 2011 at 1:02 pm

Most liveable alien worlds ranked

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A Two-Tiered Approach to Assessing the Habitability of Exoplanets

EARTH SIMILARITY INDEX
Earth – 1.00
Gliese 581g – 0.89
Gliese 581d – 0.74
Gliese 581c – 0.70
Mars – 0.70
Mercury – 0.60
HD 69830 d – 0.60
55 Cnc c – 0.56
Moon – 0.56
Gliese 581e – 0.53

PLANET HABITABILITY INDEX
Titan – 0.64
Mars – 0.59
Europa – 0.49
Gliese 581g – 0.45
Gliese 581d – 0.43
Gliese 581c – 0.41
Jupiter – 0.37
Saturn – 0.37
Venus – 0.37
Enceladus – 0.35

Saturn's moon Titan bears many similarities to the early Earth

Scientists have outlined which moons and planets are most likely to harbour extra-terrestrial life.

Among the most habitable alien worlds were Saturn’s moon Titan and the exoplanet Gliese 581g – thought to reside some 20.5 light-years away in the constellation Libra.

The international team devised two rating systems to assess the probability of hosting alien life.

They have published their results in the journal Astrobiology.

In their paper, the authors propose two different indices: an Earth Similarity Index (ESI) and a Planetary Habitability Index (PHI).

“The first question is whether Earth-like conditions can be found on other worlds, since we know empirically that those conditions could harbour life,” said co-author Dr Dirk Schulze-Makuch from Washington State University, US.

“The second question is whether conditions exist on exoplanets that suggest the possibility of other forms of life, whether known to us or not.”

As the name suggests, the ESI rates planets and moons on how Earth-like they are, taking into account such factors as size, density and distance from the parent star.

The PHI looks at a different set of factors, such as whether the world has a rocky or frozen surface, whether it has an atmosphere or a magnetic field.

It also considers the energy available to any organisms, either through light from a parent star or via a process called tidal flexing, in which gravitational interactions with another object can heat a planet or moon internally.

And finally, the PHI takes into account chemistry – such as whether organic compounds are present – and whether liquid solvents might be available for vital chemical reactions.

The maximum value for the Earth Similarity Index was 1.00 – for Earth, unsurprisingly. The highest scores beyond our solar system were for Gliese 581g (whose existence is doubted by some astronomers), with 0.89, and another exoplanet orbiting the same star – Gliese 581d, with an ESI value of 0.74.

The Gliese 581 system has been well studied by astronomers and comprises four – possibly five – planets orbiting a red dwarf star.

HD 69830 d, a Neptune-sized exoplanet orbiting a different star in the constellation Puppis, also scored highly (0.60). It is thought to lie in the so-called Goldilocks Zone – the region around its parent star where surface temperatures are neither too hot nor too cold for life.

The highly rated worlds from our own solar system were Mars, with a value of 0.70, and Mercury, with 0.60.

The Planet Habitability Index produced different results. The top finisher here was Saturn’s moon Titan, which scored 0.64, followed by Mars (0.59) and Jupiter’s moon Europa (0.47), which is thought to host a susbsurface water ocean heated by tidal flexing.

The highest scoring exoplanets were, again Gliese 581g (0.49) and Gliese 581d (0.43).

In recent years, the search for potentially habitable planets outside our solar system has stepped up several gears. Nasa’s Kepler space telescope, launched into orbit in 2009, has found more than 1,000 candidate planets so far.

Future telescopes may even be able to detect so-called biomarkers in the light emitted by distant planets, such as the presence of chlorophyll, a key pigment in plants.
www.bbc.co.uk

Written by physicsgg

November 24, 2011 at 7:24 am

White House: there is no evidence that aliens exist

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Administration response to website petition denies knowledge of life outside Earth is being hidden from public

The White House has said it has no evidence that extraterrestrial creatures exist.

Barack Obama’s administration made the declaration on Monday in response to feedback on its website, which allows people to submit petitions to which officials must respond if enough people sign.

In this case, more than 5,000 people signed a petition demanding that the White House disclose the government’s knowledge of extraterrestrial beings. More than 12,000 signed another petition seeking formal acknowledgment of an extraterrestrial presence engaging with the human race.

In response, Phil Larson of the White House office of science and technology policy wrote that the US government has no evidence that life exists outside Earth, or that an extraterrestrial presence has contacted any member of the human race.

“In addition, there is no credible information to suggest that any evidence is being hidden from the public’s eye,” Larson wrote.

However, he did not close the door entirely on a close encounter of an alien kind, noting that many scientists and mathematicians believe the chances are high that there is life somewhere among the “trillions and trillions of stars in the universe” – although the chances that humans might make contact with non-humans are remote.

It is not the first petition to force the White House to engage on a somewhat offbeat topic since the “We the People” web page was inaugurated in September. Various petitions demanding the legalisation of marijuana have gathered more than 100,000 names, to which the White House has responded that marijuana is associated with addiction, respiratory disease and cognitive impairment, and legalising it would not be the answer.

The administration has also addressed topics including gay marriage and student loan debt.

http://www.guardian.co.uk

Written by physicsgg

November 8, 2011 at 2:03 pm

Posted in UFO

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WHERE DO ALIEN CIVILIZATIONS HANG OUT?

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NASA’s Kepler space telescope is finding lots and lots of extrasolar planets. But how many might support intelligent life? And, is there a “sweet spot” in the galaxy where SETI astronomers should aim their telescopes?

I’d say we have already stumbled across that sweet spot three decades ago, but more on that later.

SLIDE SHOW: Top 10 Places To Find Alien Life

First, we need to understand what are the prerequisites for the evolution of life beyond microbes. Because we only have one example — Earth — extrapolations are dicey. For example, if completely water-covered worlds are more common than estimated, chances for advanced surface life go down. What’s more, only surface dwellers could develop technological civilizations….. Read the rest of this entry »

Written by physicsgg

October 6, 2011 at 7:00 am

Telescope to spot aliens

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World’s largest eye on the sky to join quest for signs of ET

The device will be built in the Chilean desert in a dome the size of a stadium

Housed in a dome almost the size of Big Ben and containing a mirror nearly half the length of a football pitch, it wasn’t exactly rocket science for astronomers to find a name for this telescope.
And, sure enough, they came up with the European Extremely Large Telescope – just about the only routine thing about the world’s largest and most powerful ‘eye on the sky’.
Astronomers reckon it may finally shed light on whether there really is life somewhere out there by helping them find Earth-like rocky worlds that are home to other beings.

And British scientists might be among the first to find out – as their work is crucial to the project.
Key instruments for the telescope will be developed thanks to £3.5million funding from the Science and Technology Facilities Council.
The device in the Atacama Desert, Chile, will be built in a dome that covers an area the size of a stadium…… Read the rest of this entry »

Written by physicsgg

October 3, 2011 at 9:16 am

“The Undetectability Conjecture” — A Radical Theory for the ‘Great Silence’

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The Fermi paradox is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations. As Enrico Fermi asked if the Universe is conducive to intelligent life, “Where is everybody?
A new answer proposed by Adrian Kent of the University of Cambridge and Perimeter Institute, is that extraterrestial life sufficiently advanced to be capable of interstellar travel or communication must be rare, since otherwise we would have seen evidence of it by now. This in turn is sometimes taken as indirect evidence for the improbability of life evolving at all in our universe.

“Intelligent species might reasonably worry about the possible dangers of self-advertisement and hence incline towards discretion” — the “Undetectability Conjecture,” put forth by Beatriz Gato-Rivera, a theoretical physicist at the Instituto de Fisica Fundamental (previously Instituto de Matematicas y Fisica Fundamental) of the CSIC (Spanish Scientific Research Council) in Madrid. According to Gato-Rivera, we may find ourselves in a universe in which there exist intelligent technological civilizations but they have chosen to be undetectable, camouflaging themselves mainly for security reasons (because advanced civilizations could also be aggressive).

“Evolutionary selection, acting on a cosmic scale,” Kent adds. “tends to extinguish species which conspicuously advertise themselves and their habitats.”

“It often seems, Kent concludes, “to be implicitly assumed, and sometimes is explicitly argued, that colonising or otherwise exploiting the resources of other planets and other solar systems will solve our problems when the Earth’s resources can no longer sustain our consumption. It might perhaps be worth contemplating more seriously the possibility that there may be limits to the territory we can safely colonise and to the resources we can safely exploit, and to consider whether and how it might be possible to evolve towards a way of living that can be sustained (almost) indefinitely on the resources of (say) our solar system alone.”

In another take on the “Fermi Paradox,” Stephen Hawking asks In his famous lecture on Life in the Universe: “What are the chances that we will encounter some alien form of life, as we explore the galaxy?”

If the argument about the time scale for the appearance of life on Earth is correct, Hawking says “there ought to be many other stars, whose planets have life on them. Some of these stellar systems could have formed 5 billion years before the Earth. So why is the galaxy not crawling with self-designing mechanical or biological life forms?”

Why hasn’t the Earth been visited, and even colonized? Hawking asks. “I discount suggestions that UFO’s contain beings from outer space. I think any visits by aliens, would be much more obvious, and probably also, much more unpleasant.”

Hawking continues: “What is the explanation of why we have not been visited? One possibility is that the argument, about the appearance of life on Earth, is wrong. Maybe the probability of life spontaneously appearing is so low, that Earth is the only planet in the galaxy, or in the observable universe, in which it happened. Another possibility is that there was a reasonable probability of forming self reproducing systems, like cells, but that most of these forms of life did not evolve intelligence.”

We are used to thinking of intelligent life, as an inevitable consequence of evolution, Hawking emphasized, but it is more likely that evolution is a random process, with intelligence as only one of a large number of possible outcomes.

Intelligence, Hawking believes contrary to our human-centric existece, may not have any long-term survival value. In comparison the microbial world, will live on, even if all other life on Earth is wiped out by our actions. Hawking’s main insight is that intelligence was an unlikely development for life on Earth, from the chronology of evolution: “It took a very long time, two and a half billion years, to go from single cells to multi-cell beings, which are a necessary precursor to intelligence. This is a good fraction of the total time available, before the Sun blows up. So it would be consistent with the hypothesis, that the probability for life to develop intelligence, is low. In this case, we might expect to find many other life forms in the galaxy, but we are unlikely to find intelligent life.”

Another possibility is that there is a reasonable probability for life to form, and to evolve to intelligent beings, but at some point in their technological development “the system becomes unstable, and the intelligent life destroys itself. This would be a very pessimistic conclusion. I very much hope it isn’t true.”

Hawkling prefers another possibility: that there are other forms of intelligent life out there, but that we have been overlooked. If we should pick up signals from alien civilizations, Hawking warns,”we should have to be wary of answering back, until we have evolved” a bit further. Meeting a more advanced civilization, at our present stage, Hawking says, “might be a bit like the original inhabitants of America meeting Columbus. I don’t think they were better off for it.”
http://www.dailygalaxy.com/my_weblog

Written by physicsgg

September 26, 2011 at 12:30 pm

Living in the Galactic Danger Zone

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Not every place within a galaxy experiences the same conditions for habitability - some parts are lethal thanks to supernovae, whilst others do not possess enough heavy elements to allow rocky planets and life to develop.

Summary: Although stars closer to the galactic center are exposed to more radiation, new research finds that there are more chances to find habitable planets there than in the outer regions of our galaxy

We know for certain that life exists in the Milky Way galaxy: that life is us. Scientists are continually looking to understand more about how life on our planet came to be and the conditions that must be met for its survival, and whether those conditions can be replicated elsewhere in the Universe. It turns out that looking at our entire Galaxy, rather than focusing just on life-giving properties of our planet or indeed the habitability of regions of our own Solar System, is a good place to start.

How far our planet orbits from the Sun, along with other factors such as atmospheric composition, a carbon cycle and the existence of water, has told astronomers much about the conditions that are required for life to not only originate, but to survive on rocky worlds. This distance from a star is referred to, quite simply, as the ‘Habitable Zone’ or sometimes the ‘Goldilocks Zone’ because conditions here are neither too hot or too cold for water to be liquid on the planet’s surface — conditions just right for life as we know it to thrive.

Copernican theory tells us that our world is a typical rocky planet in a typical planetary system. This concept has spurred some astronomers to start thinking bigger, way beyond the simplicity of any one planetary system and instead towards much grander scales. Astronomers are exploring whether there is a Galactic Habitable Zone (GHZ) in our Galaxy – a region of the Milky Way that is conducive to forming planetary systems with habitable worlds. The Galactic Habitable Zone implies that if there are conditions just right for a planet around a star, then the same must go for a galaxy.

A supernova sterilizes an alien world in this artist's impression.

This concept was first introduced by geologist and paleontologist Peter Ward and Donald Brownlee, an astronomer and astrobiologist, in their book, ‘Rare Earth’. The idea of a GHZ served as an antagonistic view point to the Copernican principle….. Read the rest of this entry »

Written by physicsgg

September 23, 2011 at 2:27 pm

Where is everybody?

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Introduction

During a lunch in the summer of 1950, physicists Enrico Fermi, Edward Teller and Herbert York were chatting about a recent New Yorker cartoon depicting aliens abducting trash cans in flying saucers. Suddenly, Fermi suddenly blurted out, “Where is everybody?”

Behind Fermi’s question was this line of reasoning: Since there are likely many other technological civilizations in the Milky Way galaxy, and since in a few tens of thousand of years at most they could have explored or even colonized many distant planets, why don’t we see any evidence of even a single extraterrestrial civilization?

Clearly the question of whether other civilizations exist is one of the most important questions of modern science. Any discovery of a distant civilization, say by analysis of microwave data, would certainly rank as among the most significant and far-reaching of all scientific discoveries.

The Drake equation

At one of the first conferences to study the possibility of extraterrestrial intelligent civilizations, Frank Drake (1930 — ) sketched out what now is commonly known as the Drake equation, which estimates the number of civilizations in the Milky Way galaxy with which we could potentially communicate:

N = R* fp ne fl fi fc L

where

N = number of civilizations in our galaxy that can communicate
R* = average rate of star formation per year in galaxy
fp = fraction of those stars that have planets
ne = average number of planets that can support life, per star that has planets
fl = fraction of the above that eventually develop life
fi = fraction of the above that eventually develop intelligent life
fc = fraction of civilizations that develop technology that signals existence into space
L = length of time such civilizations release detectable signals into space.

The values used by Drake in 1960 were R = 10, fp = 0.5, ne = 2, fl = 1, fi = 0.01, fc = 0.01, L = 10,000, so that N = 10 x 0.5 x 2 x 1 x 0.01 x 0.01 x 10,000 = 10.  That is, he estimated that ten such civilizations were out somewhere in the Milky Way.

In the wake of these analyses, scientists proposed the Search for Extraterrestrial Intelligence (SETI) project, to search the skies for radio transmissions from distant civilizations in a region of the electromagnetic spectrum thought to be best suited for interstellar communication. But after 50 years of searching, using increasingly powerful equipment, nothing has been found. So where is everybody?

Proposed solutions to Fermi’s paradox

Numerous scientists have examined Fermi’s paradox and have proposed solutions. Here is a brief listing of some of the proposed solutions, and common rejoinders:

  1. They are here, or at least are observing us, but are under strict orders not to disclose their existence. Common rejoinder: This explanation (often termed the “zookeeper’s theory”) is preferred by some scientists including, for instance, the late astronomer Carl Sagan. But it falls prey to the inescapable fact that it just takes one member of an extraterrestrial society to break the pact of silence.
  2. They have been here and planted seeds of life, or perhaps left messages in DNA. Common rejoinder: The notion that life began on earth from bacterial spores or the like that originated elsewhere, known as the “panspermia” theory, only pushes the problem of the origin of life to some other star system.  More controversially, Francis Crick has suggested “directed panspermia,” but few scientists take his theory seriously.  With regards to DNA, scientists see no evidence in DNA sequences of anything artificial.
  3. They exist, but are too far away. Common rejoinder: Once a civilization is sufficiently advanced, it could send probes to distant stars, which could scout out suitable planets, land, and then construct additional copies of themselves, using the latest software beamed from earth. In this way the entire Milky Way galaxy could be explored within at most a few million years.
  4. They exist, but have lost interest in interstellar communication and/or transportation. Common rejoinder: As with item #1, this explanation requires that each and every member of these civilizations forever lacks interest in communication and transportation. And all it takes is one exception, and this “solution” falls.
  5. They are calling, but we do not recognize the signal. Common rejoinder: This may be, but this explanation doesn’t apply to signals that are sent with the direct purpose of communicating to nascent technological societies. And as with item #1, it is hard to see how a galactic society could enforce a global ban on such targeted communications.
  6. Civilizations like us invariably self-destruct. Common rejoinder: This contingency is already figured into the Drake equation in the L term (the average length of a civilization). In any event, from our experience we have survived at least 100 years of technological adolescence, and have managed not yet to destroy ourselves in a nuclear or biological apocalypse. Besides, soon we will colonize the Moon and Mars, and our long-term survival will no longer rely solely on planet Earth.
  7. The earth is a unique planet in fostering a long-lived biological regime that ultimately results in the emergence of intelligent life. Common rejoinder: Such arguments may have some merit, but the latest studies, in particular the detections of extrasolar planets (see below), point in the opposite direction, namely that environments like ours appear to be quite common.
  8. We are alone, at least within the realm of the Milky Way galaxy. Some scientists in this camp further conclude that we are alone in the entire observable universe. Common rejoinder: This conclusion flies in the face of the “principle of mediocrity,” namely the presumption, popular since the time of Copernicus, that there is nothing special about the human society or environment.

Numerous other proposed solutions and rejoinders are given in [Webb2002].

Extrasolar planets

Two key terms in the Drake equation are fp (the fraction of stars that have planets) and ne (the average number of planets that can support life, per star that has planets). Scientists once thought that stable planetary systems in general, and earth-like planets in particular, were a rarity.

A breakthrough came in September 2010, when Steven S. Vogt of the University of California, Santa Cruz, and R. Paul Butler, of the Carnegie Institution in Washington, discovered evidence of a planet only three or four times the mass of earth orbiting in the “habitable zone” of a star (i.e., at a distance from a star where water could exist) about 20 light-years away from earth. As Butler noted, “This is really the first Goldilocks planet.”

More recently, NASA deployed the Kepler spacecraft, which searches for planets circulating other stars by measuring small fluctuations in their light reaching earth. In some of the initial findings, announced in February 2011, 1325 planets have been found orbiting around the 150,000 stars surveyed. Of these planets, 68 are earth-sized, and most appear to be in the habitable region around their respective stars. Extrapolation from this data suggests that as many as 10% of all stars in the Milky Way may have earth-sized planets orbiting them [Hooper2011]. A separate team of scientists, using a telescope in Chile and a different detection technique (radial velocity), recently announced the discovery of 50 new planets orbiting distant stars, several of which are approximately the earth’s mass and near the habitable zone around their respective stars [Vastag2011a].

We should add, however, that many Kepler sightings in particular remain to be ‘confirmed.’ Thus one might legitimately wonder how mathematically robust are the underlying determinations of velocity, imaging, transiting, timing, micro-lensing, etc.?

Conclusion

In short, among the factors in the Drake equation, two that have proven amenable to experimental study have been found to have reasonable values, although not quite as optimistic as Drake and his colleagues first estimated.

With every new research finding in the area of extrasolar planets and possible extraterrestrial living organisms, the mystery of Fermi’s paradox deepens. Indeed, “Where is everybody?” has emerged as one of the most significant scientific questions of our time.

Astronomer Paul Davies concludes his latest book on the topic by stating his own assessment: “my answer is that we are probably the only intelligent beings in the observable universe and I would not be very surprised if the solar system contains the only life in the observable universe.” Nonetheless, Davies reflects, “I can think of no more thrilling a discovery than coming across clear evidence for extraterrestrial intelligence.” [Davies2010, pg. 207-208].

References

  1. [Davies2010] Paul Davies, The Eerie Silence: Renewing Our Search for Alien Intelligence, Houghton Mifflin Harcourt, New York, 2010.
  2. [Hooper2011] Rowan Hooper, “Exoplanet explosion sparks philosophical debate,” New Scientist, 21 Feb 2011, available at Online article.
  3. [Vastag2011a] Brian Vastag, “New ‘super-Earth’ that is 36 light-years away might hold water, astronomers say,” Washington Post, 12 Sep 2011, available at Online article.
  4. [Webb2002] Stephen Webb, If the Universe Is Teeming with Aliens… Where Is Everybody? Fifty Solutions to Fermi’s Paradox and the Problem of Extraterrestrial Life, Copernicus Books, New York, 2002.

http://experimentalmath.info/blog/2011/09/where-is-everybody/

Written by physicsgg

September 17, 2011 at 7:15 am