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Wednesday, July 23, 2014

HOW GOES THE SEARCH FOR EXTRA TERRESTIALS


BLACK WIDOW--The fireworks above emit from NGC 4258 or M106 galaxy about 23 million light years away.  This galactic light show involves a giant black hole, shock waves and vast reservoirs of gas. This galaxy, which looks similar to our Milky Way, is famous, however, for something that our galaxy doesn’t have – two extra spiral arms that glow in X-ray, optical and radio light. Because NGC 4258 is relatively close to Earth, astronomers can study how this black hole is affecting its galaxy in great detail. The supermassive black hole at the center of NGC 4258 is about ten times larger than the one in the Milky Way and is consuming material at a faster rate and in 300 million years may peter out.

Source: NASA
SAME OLD, SAME OLD?—July 19, a few days ago, was the 45th anniversary of NASA’s Apollo 11 landing on Earth’s moon.  After the Apollo missions ended in the early 1970s, mankind has taken no big steps or leaps to return.  Any one with a minuscule command of the obvious will understand NASA or any other collection of rocket brains believe that ETs exist on our moon.

But what about the rest of the universe?
How goes the search?
Is anyone on earth looking for ETs?

Glad you asked. There is an organization headquartered in the San Francisco Bay Area city of Mountain View, CA that works 24-7, 365 to find life beyond Earth,  Called the SETI Institute (Seeking Extra Terrestrial Intelligence) the non-profit, non-government, org’s mission is to explore, understand and explain the origin, nature and prevalence of life in the universe.

So, let’s cut to the chase. 

Q. How goes the search? Have SETI Institute scientists found life, or evidence of life, on any other planets?
SETI: No.

Q: Hmm. Can you expand on that?
SETI: Nada. Zilch. Zero.  SETI scientists have found no clear indications of life, past or present, beyond the Earth. There have been several tantalizing suggestions – that the Viking mission might have detected evidence of microbial life on Mars or that there are fossil microbes in some Mars rocks or meteorites – but none of these claims has been verified.

Q. Why do humans think that life is out there?
SETI: Over the last half-century, scientists have developed a theory of cosmic evolution that predicts that life is a natural phenomenon likely to develop on planets with suitable environmental conditions. Scientific evidence shows that life arose on Earth relatively quickly (only 100 million years after life was even possible), suggesting that life will occur on any planets that have the requisite characteristics, such as liquid oceans (either on the surface or underground). With the recent discovery that the majority of stars have planets – the number of potential habitats for life has been greatly expanded.

In addition, exploration of our own solar system and analysis of the composition of other systems suggest that the chemical building blocks of life – such as amino acids – are naturally produced and very widespread.

There are several hundred billion other stars in our Galaxy, and more than 100 billion other galaxies in the part of the universe we can see. It would be extraordinary if we were the only thinking beings in all these vast realms.  It has been estimated that light needs 100,000 years to travel from one end of the Milky Way Galaxy to the other.

Q: How long have astronomers been looking for extraterrestrial signals?
SETI: The first scientific paper on using radio waves to transmit information over interstellar distances was published in the journal Nature in 1959 by physicists Phillip Morrison and Giuseppe Cocconi. In the following year, Frank Drake (now at the SETI Institute) conducted the first radio search for evidence of technology in other solar systems using an 85-foot antenna at the National Radio Astronomy Observatory in Green Bank, West Virginia. Drake called his search Project Ozma, and observed two Sun-like stars, each about 12 light-years away. Since then, approximately 100 searches have been conducted by dozens of astronomers in several countries. However, note that the technology of today’s searches greatly surpasses that of earlier efforts.

Q: Let’s back up a bit.  What is the SETI Institute?
SETI: The SETI Institute is a non-profit corporation that serves as an institutional home for research and educational projects relating to the study of life in the universe. The Institute conducts research in a number of fields including astronomy and planetary sciences, chemical evolution, the origin of life, biological and cultural evolution.

Institute projects have been sponsored by the NASA Ames Research Center, NASA Headquarters, the National Science Foundation, the Department of Energy, the US Geological Survey, the Jet Propulsion Laboratory (JPL), the International Astronomical Union, Argonne National Laboratory, the Alfred P. Sloan Foundation, the David and Lucile Packard Foundation, the Paul G. Allen Foundation, the Moore Family Foundation, the Universities Space Research Association (USRA), the Pacific Science Center, the Foundation for Microbiology, Sun Microsystems, Hewlett Packard Company, other private industry, William and Rosemary Hewlett, Bernard M. Oliver and many other private donations. The Institute welcomes support from private foundations or other groups or individuals interested in our work.

Each funded effort is supervised by a principal investigator who is responsible to the Board of Trustees for the conduct of the activity. There are currently over one hundred active projects, involving more than 50 scientists at the Institute investigating Mars, planetary science, exobiology and related topics. In addition, the Institute’s SETI group is conducting several searches for extraterrestrial intelligence.

Among the Institute’s educational activities are both formal and informal education – including outreach connected with NASA’s Kepler Mission – frequent talks by our scientists, a weekly colloquium open to the public and a weekly, one-hour radio program on science (“Big Picture Science”) now carried by more than 80 broadcast stations.  “Big Picture Science” can be most easily found at bigpicturescience.org, where you can immediately play this week’s show, or any of hundreds of archived programs. More than eighty radio stations carry the program, and the web site will tell you if there’s a station in your area. The show is also available from several podcast outlets, including iTunes.

Q:  If SETI hasn’t discovered ETs have we discovered any signals from them?
SETI: No. SETI search has yet received a confirmed, extraterrestrial signal. If we had, the world would know about it. There is no policy of secrecy, and any promising signal would quickly prompt observations at other observatories.

In the past, there were several unexplained and intriguing signals detected in SETI experiments. Perhaps the most famous of these was the “Wow” signal picked up at the Ohio State Radio Observatory in 1977. However, none of these signals was ever detected again, and for scientists that’s not good enough to claim success and boogie off to Stockholm to collect a Nobel Prize. Who would believe cold fusion unless many researchers could duplicate it in their labs? The same is true of extraterrestrial signals: they are credible only when they can be found more than once.

Q. How would we know that the signal is from ET?
SETI: Virtually all radio SETI experiments have looked for what are called “narrow-band signals.” These are radio emissions that extend over only a small part of the radio spectrum. Imagine tuning your car radio late at night … There’s static everywhere on the dial, but suddenly you hear a squeal – a signal at a particular frequency – and you know you’ve found a station.

Narrow-band signals – perhaps only a few Hertz wide or less – are the mark of a purposely built transmitter. Natural cosmic noisemakers, such as pulsars, quasars, and the turbulent, thin interstellar gas of our own Milky Way, do not make radio signals that are this narrow. The static from these objects is spread all across the dial.

In terrestrial radio practice, narrow-band signals are often called “carriers.” They pack a lot of energy into a small amount of spectral space, and consequently are the easiest type of signal to find for any given power level. If E.T. intentionally sends us a signal, those signals may well have at least one narrow-band component to get our attention.

Q. What happens if we find something?
SETI: Keep in mind that the receivers used for SETI are designed to find constant or slowly pulsed carrier signals … something like a flute tone played against the noise of a waterfall. But any rapid variation in the signal – known as modulation, or more colloquially as the “message” – can be smeared out and lost. This is because – to gain sensitivity – SETI receivers average the incoming signals for seconds or minutes.

If E.T.’s electric bills are high (as on Earth) and his received signals are therefore relatively weak, we may have to build far larger instruments to look for the modulation. Fortunately, once a detection is made, we expect the money will become available to do so.

Until we can detect the modulation, we’ll know only a few things about the beings on the other end. We can pinpoint the spot on the sky where the signal is coming from, and slow changes in its frequency will tell us something about the rotation and orbital motion of E.T.’s home planet.

But even though this information is limited, the detection of alien intelligence will be an enormously big story. We’ll be aware that we’re neither alone nor the smartest things in the universe. And of course there will be a clamor to build the big dishes that would allow us to pick up E.T.’s message.

Q. Could we ever understand the message?
SETI: No one knows. It’s conceivable that an advanced and altruistic civilization will send us simple pictures and other information. They might do this because they are hundreds (or more) light-years’ distant. That would make real back-and-forth communication tedious at best, so these alien broadcasters might be tempted to send lots of information, and in a format that we could eventually decipher. Then again, we might pick up a signal that was never intended for us, in which case it might be impossible to figure it out.

Q. Will alien senders have any way of knowing that their signal has been received by us?
SETI: No. They wouldn’t be aware that we had received their message any more than a radio disk jockey knows that you’ve tuned in his show. For the extraterrestrials to know, we would have to send a message in reply. Whether or not sending a reply is a good idea is still controversial. It’s worth noting, however, that a complete message exchange might take decades due to the finite speed of light.

Q: Would it be dangerous to reply?
SETI: While we can’t pretend to know the behavior or motivations of extraterrestrials, there’s little point in worrying about alerting others to our presence by replying to a signal detected by SETI. That’s because we have been unintentionally broadcasting the fact of our existence into space ever since the Second World War. Any society capable of interstellar travel – and therefore be a possible threat – would be able to detect these signals. In other words, the evidence for our presence on Earth is already moving into space, and has so far reached several thousand star systems.

Q: What happens if you detect a signal?
SETI: The first thing to do is to confirm that it’s truly extraterrestrial. Remember, with tens of millions of channels and antennas that are among the world’s largest, SETI picks up thousands of signals daily. An important test to verify that a signal is truly extraterrestrial would be a confirming observation at another radio telescope.

Once an artificial signal is confirmed as being of extraterrestrial intelligent origin, the discovery will be announced as quickly and as widely as possible. There will be no secrecy, and indeed getting the word out quickly is important as there would be an urgent need to have astronomers world-wide monitor any detected signal, 24 hours a day.


Q. How would you know what the signal means – the message?
SETI: The simplest SETI searches search for a “carrier” – a narrow-band signal – that could underpin a transmission. A carrier is just a simple tone, and doesn’t convey any information itself. The message, if there is any, might be much weaker.

If we do succeed in finding a message, could we understand it? If the signal is intentional, it might be decipherable. In order to send or receive a signal over interstellar distances, a civilization must understand basic science and mathematics. Hence, a message from another civilization might use science and math (or simply pictures) to build up a common language with other societies.

Although, signals sent by a civilization for its own purposes may be impossible to unravel, SETI scientists are developing statistics-based algorithms to determine the amount of information sent. This can tell us, almost immediately, something about their level of intelligence.

Q. Why do SETI at all?
SETI: There are many reasons, including such practical considerations as the technological spinoff. But SETI research is first and foremost pursued because it is designed to answer questions that previous generations could only ask. How do we fit into the biological scheme of the cosmos? Is intelligent life a rare event or a common one in the universe? Can technological civilizations last for long periods of time, or do they inevitably self-destruct or die out for some other reason?

If we could understand any signal that we detect, there’s always the possibility that it would contain enormously valuable knowledge. It’s likely that any civilization we discover will be far more advanced than ours, and might help us to join a galactic network of intelligent beings. But even if we detect a signal without being able to understand it, that would still tell us that we are not unique in the cosmos. The effect on society might be as profound and long lasting as when Copernicus displaced the Earth from the center of our universe.

Q.  Who believes in you?
SETI: Current SETI searches are funded by donations, mostly from individuals among the public and a few foundations and corporations. Major donors have included William Hewlett, David Packard, Gordon Moore, Paul Allen, Nathan Myhrvold, Arthur C. Clarke, Barney Oliver, and Franklin Antonio.

Q:  Can the public become a member of the SETI Institute?
SETI: Yes! Learn more about the SETI Institute’s membership program, TeamSETI at www.seti.org

You can keep up with the daily SETI search at http://setiquest.info/ and beta test our online human-powered search at http://www.setilive.org/.



Tuesday, July 22, 2014

CIVIL WAR CHRONICLE / THE BATTLE FOR ATLANTA



Example of Northern newspaper coverage of the Fall of Atlanta, summer 1864
BEGINNING OF THE END--The American Civil War Battle for Atlanta was a pivotal summer long struggle, which began July 22, 1864 and ended on September 2, 1864   after a Union siege and various attempts to seize railroads and supply lines leading to Atlanta.

After defeating rebel troops led by Gen. John B . Hood, Union forces led by Gen. William T. Sherman headed south-southeastward toward Milledgeville, the State capital, and on to Savannah with the March to the Sea.

The fall of Atlanta was especially noteworthy for its political ramifications. In the 1864 election, former Union General George B. McClellan, a Democrat, ran against President Lincoln on a peace platform calling for truce with the Confederacy. The capture of Atlanta and Hood's burning of military facilities as he evacuated were extensively covered by Northern newspapers, significantly boosting Northern morale, and Lincoln was reelected by a large margin.—Wikipedia Free Encyclopedia.