Posts tagged extraterrestrials

     You are hovering some planet in a galaxy far far away, uncertain whether it is made of matter or antimatter and hence whether or not it will be safe to land. The planet is inhabited by friendly aliens with whom you have made radio contact. They are very intelligent and understand you, and being advanced, know all about matter and antimatter.

     Naturally, they insist that they are made of matter; after all, it would be surprising if anyone chose to define their own stuff as ‘anti.’ How can we decide if their dictionary and ours coincide? What questions will unambiguously reveal whether they are made of the same stuff as us, or are anti-aliens?

     If matter and antimatter were always perfectly symmetrically counterpoised, there would be no way to settle the issue, other than gambling with a close approach of firing a tiny unmanned probe and seeing what  happens when it hits the atmosphere or anti-atmosphere. However, we know that there is an asymmetry, small but measurable, and that is what the electrically neutral variety of K mesons can reveal. They do so when they decay, producing a pion that is either positively or negatively charged accompanied by an electron or positron respectively. If matter and antimatter were perfect opposites, these two decays would also be precisely matched, the chance of each being the same. In reality, they are slightly different.

     The neutral K and anti-K are welded together in nature in such a way that they sometimes die quickly, but at other times live longer. The two possibilities are quite distinct and are known as the short- and long-lived versions. Each of these shows an asymmetry between matter and antimatter, but it is the long-lived one where the effect is biggest, they decay that leads to a positron being slightly more likely to happen than giving an electron: out of every two-thousand examples, on the average, 1,003 will give a positron and 997 give an electron. Now at last we have something to discuss with the alien.

     First, identify the K. It is no use giving its name, since the alien will certainly call it something else, but we can identify it by something we will agree about: its mass. It weighs in at slightly more than half the mass of a proton or antiproton and there are no other particles than can be confused with it. So tell the alien that we are interested in a particle whose mass is slightly more than half that of the massive particle that exists in the ‘nucleus’ at the center of the alien’s simplest atom, the proton in the hydrogen atom (or antiproton in an atom of antihydrogen.) That identifies the K.

     In addition to the neutral K, with no electric charge, there are also a K-plus and K-minus with positive or negative charge. So we much make sure that the alien and we are talking about the electrically neutral version. We must say that the property that holds the atom together is what we call ‘charge’ and that we are interested in the K that has no charge. The alien will be aware that this neutral K has two forms: one with a short life and one with a relatively long one. It is the latter that we will focus on.

     Now we come to the critical bit. In our world of matter, when the long-lived K decays into a pion and an electron or positron, it is the positron mode that is the most likely. So we ask the alien: ‘Is the lightweight particle that is produced most often in these decays the same as you find in your atoms, or is it the opposite?’ If the alien answers that it is the same, it is a positron, the alien is made of antimatter and we should look but not touch. If the alien replies that it is the opposite, an electron, then we are all made of matter and it is safe to land.

Antimatter, Frank Close

21:56 09 May 2011 by David Shiga

No one has ever floated a boat on another world, but NASA is now considering doing just that, on Saturn’s icy moon Titan. Probing the moon’s hydrocarbon lakes could reveal clues to its climate and perhaps even signs of exotic life forms.

Titan’s surface is dotted with lakes, making it strangely reminiscent of Earth. But rather than water, the lakes are filled with a mixture of methane and ethane, which are gases on Earth but are liquid at Titan’s surface temperature of -180 °C.

NASA is now considering sending a probe to splash down into one of the lakes. It has selected a mission called the Titan Mare Explorer (TiME) as one of three finalists competing for a chance to fly in 2016. The TiME project is led by Ellen Stofan of Proxemy Research in Gaithersburg, Maryland.

In 2023, after a seven-year cruise from Earth, TiME would parachute into a lake in Titan’s northern hemisphere called Ligeia Mare. Powered by heat from the decay of an onboard plutonium supply, the probe would bob around the lake’s surface and make measurements for about three months.

Titan is the only place in the solar system that appears to have a cycle analogous to the water cycle on Earth, with hydrocarbon rain depositing liquid on the surface, followed by evaporation and more rain.

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The Allen Telescope Array in California is designed to look for signs of alien signals and handle other astronomy projects.

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Conspiracy theorists might say the one-world government “don’t need no stinking protocols,” to paraphrase a classic movie scene. And it’s true that the protocols are not legally binding. But the SETI League found it comforting that the experts declared their commitment to openness in the search for extraterrestrial intelligence.

“The advent of the Internet has changed the way the world does collaborative science,” H. Paul Shuch, the grassroots group’s executive director emeritus, said in a statement released over the weekend. “The revised IAA SETI Protocols better reflect this reality and provide a workable means for honoring both scientific integrity and the public’s right to know.”

Here’s the text of the revised protocols, which are posted on the SETI League website:

Preamble

The parties to this declaration are individuals and institutions participating in the scientific Search for Extraterrestrial Intelligence (SETI).

The purpose of this document is to declare our commitment to conduct this search in a scientifically valid and transparent manner and to establish uniform procedures for the announcement of a confirmed SETI detection.

This commitment is made in recognition of the profound scientific, social, ethical, legal, philosophical and other implications of a SETI detection. As this enterprise enjoys wide public interest, but engenders uncertainty about how information collected during the search will be handled, the signatories have voluntarily constructed this declaration. It, together with a current list of signatory parties, will be placed on file with the International Academy of Astronautics (IAA).

Principles

1. Searching: SETI experiments will be conducted transparently, and its practitioners will be free to present reports on activities and results in public and professional fora. They will also be responsive to news organizations and other public communications media about their work.

2. Handling candidate evidence: In the event of a suspected detection of extraterrestrial intelligence, the discoverer will make all efforts to verify the detection, using the resources available to the discoverer and with the collaboration of other investigators, whether or not signatories to this Declaration. Such efforts will include, but not be limited to, observations at more than one facility and/or by more than one organization. There is no obligation to disclose verification efforts while they are underway, and there should be no premature disclosures pending verification. Inquiries from the media and news
organizations should be responded to promptly and honestly.

Information about candidate signals or other detections should be treated in the same way that any scientist would treat provisional laboratory results. The Rio Scale, or its equivalent, should be used as a guide to the import and significance of candidate discoveries for the benefit of non-specialist audiences.

3. Confirmed detections: If the verification process confirms – by the consensus of the other investigators involved and to a degree of certainty judged by the discoverers to be credible – that a signal or other evidence is due to extraterrestrial intelligence, the discoverer shall report this conclusion in a full and complete open manner to the public,
the scientific community, and the Secretary General of the United Nations. The confirmation report will include the basic data, the process and results of the verification efforts, any conclusions and intepretations, and any detected information content of the signal itself. A formal report will also be made to the International Astronomical Union
(IAU).

4. All data necessary for the confirmation of the detection should be made available to the international scientific community through publications, meetings, conferences, and other appropriate means.

5. The discovery should be monitored. Any data bearing on the evidence of extraterrestrial intelligence should be recorded and stored permanently to the greatest extent feasible and practicable, in a form that will make it available to observers and to the scientific community for further analysis and interpretation.

6. If the evidence of detection is in the form of electromagnetic signals, observers should seek international agreement to protect the appropriate frequencies by exercising the extraordinary procedures established within the World Administrative Radio Council of the International Telecommunication Union.

7. Post Detection: A Post-Detection Task Group under the auspices of the IAA SETI Permanent Study Group has been established to assist in matters that may arise in the event of a confirmed signal, and to support the scientific and public analysis by offering guidance, interpretation, and discussion of the wider implications of the detection.

8. Response to signals: In the case of the confirmed detection of a signal, signatories to this declaration will not respond without first seeking guidance and consent of a broadly representative international body, such as the United Nations.

Unanimously adopted by the SETI Permanent Study Group of the International Academy of Astronautics, at its annual meeting in Prague, Czech Republic, on 30 September 2010.

These revised and streamlined Protocols are intended to replace the previous document adopted by the International Academy of Astronautics in 1989.

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by Jon Voisey on May 6, 2011

When last we checked in on Gliese 581d, a team from the University of Paris had suggested that the popular exoplanet, Gliese 581d may be habitable. This super-Earth found itself just on the edge of the Goldilocks zone which could make liquid water present on the surface under the right atmospheric conditions. However, the team’s work was based on one dimensional simulations of a column of hypothetical atmospheres on the day side of the planet. To have a better understanding of what Gliese 581d might be like, a three dimensional simulation was in order. Fortunately, a new study from the same team has investigated the possibility with just such an investigation.

The new investigation was called for because Gliese 581d is suspected to be tidally locked, much like Mercury is in our own solar system. If so, this would create a permanent night side on the planet. On this side, the temperatures would be significantly lower and gasses such as CO₂ and H₂O may find themselves in a region where they could no longer remain gaseous, freezing into ice crystals on the surface. Since that surface would never see the light of day, they could not be heated and released back into the atmosphere, thereby depleting the planet of greenhouse gasses necessary to warm the planet, causing what astronomers call an “atmospheric collapse.”

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Pioneers 10 and 11, which preceded Voyager, both carried small metal plaques identifying their time and place of origin for the benefit of any other spacefarers that might find them in the distant future. With this example before them, NASA placed a more ambitious message aboard Voyager 1 and 2-a kind of time capsule, intended to communicate a story of our world to extraterrestrials. The Voyager message is carried by a phonograph record-a 12-inch gold-plated copper disk containing sounds and images selected to portray the diversity of life and culture on Earth.

Following the section on the sounds of Earth, there is an eclectic 90-minute selection of music, including both Eastern and Western classics and a variety of ethnic music. Once the Voyager spacecraft leave the solar system (by 1990, both will be beyond the orbit of Pluto), they will find themselves in empty space. It will be forty thousand years before they make a close approach to any other planetary system. As Carl Sagan has noted, “The spacecraft will be encountered and the record played only if there are advanced spacefaring civilizations in interstellar space. But the launching of this bottle into the cosmic ocean says something very hopeful about life on this planet.”

The definitive work about the Voyager record is “Murmurs of Earth” by Executive Director, Carl Sagan, Technical Director, Frank Drake, Creative Director, Ann Druyan, Producer, Timothy Ferris, Designer, Jon Lomberg, and Greetings Organizer, Linda Salzman. Basically, this book is the story behind the creation of the record, and includes a full list of everything on the record. “Murmurs of Earth”, originally published in 1978, was reissued in 1992 by Warner News Media with a CD-ROM that replicates the Voyager record. Unfortunately, this book is now out of print, but it is worth the effort to try and find a used copy or browse through a library copy.

(Source: voyager.jpl.nasa.gov)

April 28, 2011: One day, years from now—or maybe billions of years, no one knows—aliens might be surprised to run across an old spaceship from Earth. Improbably far from home, the ancient probe is space cold, its nuclear power source spent long ago; an iconic white antenna points silently into the void, beaming no data to the species that made it. Yet this Voyager may speak to its finders.

A golden record is fixed to the side of the probe, and if ET can decipher it, he might be surprised again, because Voyager has a story to tell—and it’s a Love Story.

Rewind to 1977.

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Financial woes have delivered a serious blow to the search for E.T. One of its best tools, the Allen Telescope Array in northern California, has been put on hold until new funding is located.

“It is a huge irony,” Jill Tarter, director of SETI research at the SETI Institute in Mountain View, Calif., told me today. ”Now we actually know where to point the telescopes to look at planets, but we don’t have the telescopes to point right now, so a very ironic situation.”

For decades, astronomers have pointed their telescopes at stars they thought were likely to have planets around them. This February, the first results from the NASA’s Kepler Mission revealed 1,235 potential worlds in orbit around distant stars.

ATA financial woes

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(source: incomprehensibleuniverse)

By now you may have heard the report that as many as 1/4 of all the sun-like stars in the Milky Way may have Earth-like worlds. Briefly, astronomers studied 166 stars within 80 light years of Earth, and did a survey of the planets they found orbiting them. What they found is that about 1.5% of the stars have Jupiter-mass planets, 6% have Neptune-mass ones, and about 12% have planets from 3 – 10 times the Earth’s mass.

This sample isn’t complete, and they cannot detect planets smaller than 3 times the Earth’s mass. But using some statistics, they can estimate from the trend that as many as 25% of sun-like stars have earth-mass planets orbiting them!

Read more …

By Alan Boyle

After nearly two decades of searching, astronomers have detected carbon monoxide in Pluto’s thin atmosphere, as they expected. But they didn’t expect to find so much of it. Pluto’s dramatic seasonal changes serve as further evidence that the dwarf planet is one surprising little bugger.

“Everything about Pluto is surprising,” Jane Greaves, an astronomer at the University of St. Andrews in Scotland, told me. Greaves presented the new results today at the Royal Astronomical Society’s National Astronomy Meeting in Wales.

Five years ago, Pluto was at the center of a controversy over the definition of planethood — which resulted in the creation of the dwarf-planet category, a new class of celestial objects. More recent observations have pointed up still more peculiarities about Pluto. For example, scientists have found that the faraway world’s surface features are changing, that its atmosphere contains clouds, and that it might even harbor a pool of liquid beneath its icy shell.

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(source: incomprehensibleuniverse)