ET Junk

From Discovery.com:
As powerful space telescopes seek out Earth-like planets, and SETI radio telescopes listen for transmissions from aliens, physical evidence for intelligent extraterrestrials might be right in our backyard.

I'm not talking about flying saucers or oddball ancient artifacts attributed to visits by so-called "space gods," however. Instead, I'm looking for something as mundane as the pieces of interstellar probes that could have visited our solar system on numerous occasions over geologic time.

If technological extraterrestrial civilizations are common in our galaxy, then they should have the wherewithal and curiosity to send robotic probes to other star systems. We already have five star-bound spacecraft destined to roam the galaxy forever: two Pioneer probes, a pair of Voyagers, and the New Horizons craft now speeding toward Pluto.

The aliens' motivations may be the same as ours; if we found an Earth-like world nearby, there would be an inevitable desire to send an unmanned craft to see what kinds of creatures are living there. We'd have a burning curiosity to behold how the power of biological evolution has played out among the stars.

Looking for alien "calling cards" in the solar system is not a new idea. It has been popularized in numerous science fiction stories and movies. In Arthur C. Clarke's 1951 short story The Sentinel, astronauts come upon an alien-built pyramid on the moon that remains inscrutable.

A recent paper by Jacob Haqq-Misra and Ravi Kumar Kopparapu of Pennsylvania State University takes a new look at this twist on the Fermi Paradox: "Where Are They?"

The authors propose that an alien probe may be as small as a car, but no bigger than a modest-sized house.

Certainly, for the propulsion demands of interstellar travel the less massive -- hence smaller -- the payload, the better. But finding it among our planets would be as difficult as finding a needle on a football field covered in three feet of hay, say the authors.

The researchers developed an equation that can be applied to a portion of the volume of the solar system and determine whether sufficient searching has been done to rule out any E.T. souvenirs.

They conclude: "Extraterrestrial artifacts may exist in the solar system without our knowledge simply because we have not yet searched sufficiently. The vastness of space implies that it will take some time before every nearby object can be considered devoid of (space probes)."

We are just beginning to take close-up look at other planets with enough sharpness to see small artifacts, if they are there...

A Solar System Littered With Alien Artifacts?
Ray Villard
Wed Nov 9, 2011
http://news.discovery.com/space/our-solar-system-might-be-littered-with-alien-artifacts-111109.html

City lights could reveal alien civilizations

Sebastian Anthony on November 1, 2011
http://www.extremetech.com/extreme/102661-city-lights-on-other-planets-could-reveal-alien-life

For the most part, our infatuation with alien life revolves around us finding them — but did you ever stop to think that in the eyes of another significantly-advanced, space-age civilization, we would be the alien race? We have SETI’s indefatigable search for foreign, deep space radio waves, Keppler’s continued (and successful) search for life-sustaining exoplanets, and biologists regularly discovering that life can form and survive in increasingly tenacious habitats. But what if aliens are watching us?

New research conducted by Abraham Loeb from Harvard and Edwin Turner from Princeton shows that electric, artificial lights on remote planets could be detected using next-generation ground and space telescopes. The basic approach is simple: planets that are exclusively illuminated by a local sun will have one “light signature,” while a planet with artificial lights will have another. Loeb and Turner say that this technique, with our current telescopes, would be able to pick out a major terrestrial city on the edge of the Solar System, in the Kuiper belt (50 AU) — but future telescopes, or the telescopes belonging to advanced, alien races, could see farther.

More interesting than the how is the why. Why are Loeb and Turner interested in weak, visible-light spectra rather than the megawatts of easily-detectable radio waves that are pumped into space every second? Because the amount of radio waves being produced by humanity — mostly thanks to fiber optic networks — is on the decline. In turn, this infers that other, advanced civilizations might have moved beyond radio communications too. In this case, radio astronomy won’t help us in the search for extraterrestrial intelligence (SETI) — but looking for artificial light would.

As long as alien life forms actually use artificial lights, of course — it would be awfully presumptuous to assume that our galactic overlords actually have eyes.

ET Phone Goldilocks

From DailyMail.co.uk:
An astronomer picked up a mysterious pulse of light coming from the direction of the newly discovered Earth-like planet almost two years ago, it has emerged.

Dr Ragbir Bhathal, a scientist at the University of Western Sydney, picked up the odd signal in December 2008, long before it was announced that the star Gliese 581 has habitable planets in orbit around it.

A member of the Australian chapter of SETI, the organisation that looks for communication from distant planets, Dr Bhathal had been sweeping the skies when he discovered a 'suspicious' signal from an area of the galaxy that holds the newly-discovered Gliese 581g.

The remarkable coincidence adds another layer of mystery to the announcement last night that scientists had discovered another planet in the system: Gliese 581g - the most Earth-like planet ever found.

Dr Bhathal's discovery had come just months before astronomers announced that they had found a similar, slightly less habitable planet around the same star 20 light years away. This planet was called Gliese 581e.

When asked about his discovery at the time Dr Bhathal admitted he had been really excited about what he had possibly stumbled across.

He told VICE Media: 'Whenever there’s a clear night, I go up to the observatory and do a run on some of the celestial objects. Looking at one of these objects, we found this signal.

'And you know, I got really excited with it. So next I had to analyse it. We have special software to analyse these signals, because when you look at celestial objects through the equipment we have, you also pick up a lot of noise.'

He went on: 'We found this very sharp signal, sort of a laser lookalike thing which is the sort of thing we’re looking for - a very sharp spike. And that is what we found. So that was the excitement about the whole thing.'

For months after his discovery Dr Bhathal scanned the skies for a second signal to see whether it was just a glitch in his instrumentation but his search came to nothing...

Dr Steven Vogt, who led the study at the University of California, Santa Cruz, today said that he was '100 per cent sure ' that there was life on the planet.

The planet lies in the star's 'Goldilocks zone' - the region in space where conditions are neither too hot or too cold for liquid water to form oceans, lakes and rivers.

The planet also appears to have an atmosphere, a gravity like our own and could well be capable of life. Researchers say the findings suggest the universe is teeming with world like our own.
'If these are rare, we shouldn't have found one so quickly and so nearby,'

'The number of systems with potentially habitable planets is probably on the order of 10 or 20 per cent, and when you multiply that by the hundreds of billions of stars in the Milky Way, that's a large number. There could be tens of billions of these systems in our galaxy.'

He told Discovery News: 'Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say that the chances for life on this planet are 100 percent. I have almost no doubt about it'.

The planet is so far away, spaceships travelling close to the speed of light would take 20 years to make the journey. If a rocket was one day able to travel at a tenth of the speed of light, it would take 200 years to make the journey...

It takes just 37 days to orbit its sun which means its seasons last for just a few days. One side of the planet always faces its star and basks in perpetual daylight, while the other is in perpetual darkness.

The most suitable place for life or future human colonists would be in the 'grey' zone - the band between darkness and light that circles the planet.

'Any emerging life forms would have a wide range of stable climates to choose from and to evolve around, depending on their longitude,' said Dr Vogt who reports the find in the Astrophysical Journal...

'This planet doesn't have days and nights. Wherever you are on this planet, the sun is in the same position all the time. You have very stable zones where the ecosystem stays the same temperature... basically forever,' Vogt said.

'If life can evolve, it's going to have billions and billions of years to adapt to the surface. Given the ubiquity of water, it seems probable that this thing actually has liquid water. On the surface of the Earth, everywhere you have liquid water you have life,' Vogt added.

Astronomers have now found six planets in orbit around Gliese 581 - the most discovered in a planetary system other than our own solar system.
Like the solar system, the planets orbiting Gliese 581 have mostly circular orbits.

Two of its detected planets have previously been proposed as habitable planets. However they lie at the extremes of the Goldilocks Zone - one on the hot side, the other on the cold side.
Gliese 581g, in contrast, lies right in the middle...

GLIESE 581g FACT FILE

Diameter - 1.2 to 1.4 times that of the Earth

Mass - 3.1 and 4.3 times that of the Earth

Average surface temperature - between -24F and 10F (-31C and -12C)

Distance from the Earth - 20 light years or 118,000,000,000,000 miles

Time needed to travel to Gliese 581g in a rocket travelling one tenth the speed of light, or 19,000 miles per second - 200 years

One of six planets to orbit the star Gliese 581

Length of year - 37 Earth days

Gravity - similar or slightly higher than Earth
Distance from its sun - around six million miles
The planet orbits a red dwarf which is 50 times cooler and a third the size of our Sun

Composition - rocky with liquid water and atmosphere.

Does ET live on Goldilocks planet? How scientists spotted 'mysterious pulse of light' from direction of newly-discovered '2nd Earth' two years ago
Niall Firth
17th August 2011
http://www.dailymail.co.uk/sciencetech/article-1316538/Gliese-581g-mystery-Scientist-spotted-mysterious-pulse-light-direction-newEarth-planet-year.html

SETI Institute to shut down alien-seeking radio dishes

Lisa M. Krieger
lkrieger@mercurynews.com
04/25/2011
http://www.mercurynews.com/science/ci_17926565

If E.T. phones Earth, he'll get a "disconnect" signal.

Lacking the money to pay its operating expenses, Mountain View's SETI Institute has pulled the plug on the renowned Allen Telescope Array, a field of radio dishes that scan the skies for signals from extraterrestrial civilizations.

In an April 22 letter to donors, SETI Institute CEO Tom Pierson said that last week the array was put into "hibernation," safe but nonfunctioning, because of inadequate government support.

The timing couldn't be worse, say SETI scientists. After millenniums of musings, this spring astronomers announced that 1,235 new possible planets had been observed by Kepler, a telescope on a space satellite. They predict that dozens of these planets will be Earth-sized -- and some will be in the "habitable zone," where the temperatures are just right for liquid water, a prerequisite of life as we know it.

"There is a huge irony," said SETI Director Jill Tarter, "that a time when we discover so many planets to look at, we don't have the operating funds to listen."

SETI senior astronomer Seth Shostak compared the project's suspension to "the Niña, Pinta and Santa Maria being put into dry dock."

"We have the radio antennae up, but we can't run them without operating funds," he added. "Honestly, if everybody contributed just 3 extra cents on their 1040 tax forms, we could find out if we have cosmic company."

The SETI Institute's mission is to explore the origin, nature and prevalence of life in the universe. This is a profound search, it believes, because it explains our place among the stars.

The program, located on U.S. Forest Service land near Mount Lassen, uses telescopes to listen for anything out of the ordinary -- a numerical sequence of "beeps," say, or crackly dialogue from an alien version of a disembodied "Charlie" talking to his "Angels." The entire program was set up to prove what once seemed unthinkable: In the universe, we are not alone.

Lack of funding

But funding for SETI has long been a headache for E.T.-seekers. NASA bankrolled some early projects, but in 1994, Sen. Richard Bryan of Nevada convinced Congress that it wasn't worth the cost, calling it the "Great Martian Chase" and complaining that not a single flying saucer had applied for FAA approval.

However, successful private funding came from donors such as Microsoft co-founder Paul Allen, allowing SETI to raise $50 million to build the 42 dishes.

Plans called for construction of 350 individual radio antennas, all working in a larger mapin concert. But what's lacking now is funding to support the day-to-day costs of running the dishes.

This is the responsibility of UC Berkeley's Radio Astronomy Laboratory, but one of the university's major funders, the National Science Foundation, supplied only one-tenth its previous support. Meanwhile, the state of California has also cut funding.

About $5 million is needed over the next two years, according to Tarter. She hopes the U.S. Air Force will help, because the array can be used to track satellite-threatening debris in space. But budgets are tight there as well.

Astronomers mourn

The Allen array is not the only radio telescope facility that can be used for SETI searches. But it is the best; elsewhere, scientists have to borrow time on other telescopes.

Meanwhile, other SETI projects will continue, such as the "setiQuest Explorer" (http://www.setiquest.org/), an application that allows citizen scientist volunteers to look for patterns from existing data that might have been missed by existing algorithms. Through a new partnership with "Galaxy Zoo" (http://www.galaxyzoo.org/), this project runs in real time, so discoveries can be followed up on immediately.

Bay Area astronomers mourned the hiatus of the SETI program and expressed concern about the future.

Rob Hawley of the Peninsula Astronomical Society called it "unfortunate. The Allen scope was a wonderful experiment. "... Hubble gets all the press, but there are lots of limitations."

Amateur astronomer Sarah Wiehe of Palo Alto said, "just knowing SETI is there was significant for us. This is a setback."

"If we miss a distant signal," she added, "it would be a terrible loss."

To learn more about SETI and its programs, go to www.seti.org.

Oops, that was a bad call, Earth

http://www.timesonline.co.uk/tol/news/science/earth-environment/article6999927.ece

The Sunday Times
January 24, 2010
Oops, that was a bad call, Earth
Some scientists want to send signals into space in search of aliens but others warn we may get more than we bargained for
Richard Woods and Chris Hastings

“CALLING all aliens, this is Earth. Are you receiving me?”
Rather than simply listening for signals of extra-terrestrial life, some scientists are preparing to take a much more active approach to finding alien intelligence on other planets.

They believe we should start beaming regular signals into space specifically to find intelligent life, even though other scientists believe it could be an invitation to danger.

“My personal view is that being more active is a worthy strategy,” said Douglas Vakoch, director of interstellar message composition at the SETI [search for extraterrestrial intelligence] Institute in California. “There is more serious talk of it, though not at the institute level.”

At an astrobiology conference in Texas in April, SETI enthusiasts will discuss new methods of discovering extraterrestrial life, including sending out interstellar messages. Alexander Zaitsev, a Russian scientist who has already beamed out four carefully composed signals to nearby stars, has been invited to attend.

In the UK, Dr Marek Kukula, public astronomer at the Royal Observatory in Greenwich, said: “Part of me is with the enthusiasts and I would like us to try to make proactive contact with a wiser, more peaceful civilisation.”

However, he warns that advertising our presence could be risky. “We might like to assume that if there is intelligent life out there it is wise and benevolent,” he said. “But of course we have no evidence for this.

“Given that the consequences of contact may not be what we initially hoped for, then we need governments and the UN to get involved in any discussions.”

The issue will be among those raised at a two-day meeting at the Royal Society in London this week, under the heading, “The detection of extraterrestrial life and the consequences for science and society”.

Among the speakers will be Professor Simon Conway Morris, a Cambridge University evolutionary biologist, who says there is good reason to think aliens exist — and that they may well have chemical and biological similarities to us.

Conway Morris, whose talk is entitled “Predicting what extraterrestrial life will be like — and preparing for the worst”, said: “My basic argument is that, contrary to most neo-Darwinian thinking at the moment, evolution is much more predictable than people think.

“In particular, I would argue that the emergence, by evolution, of intelligence, cognitive capacity and all that stuff is an inevitability.”

In short, under the right conditions of a “biosphere” such as that present on Earth, the molecules necessary to form complex and intelligent life are already available; Darwinian evolution will do the rest.

“I think we can argue some intelligence must emerge in a biosphere,” said Conway Morris. “If that is correct — and it applies to manipulative skill — then that suggests there should be alien technologies.”

Astronomers have already discovered about 300 planets beyond our solar system, and some suggest it is only a matter of time before more Earth-like planets are identified.

That suggests there should be “lots of extraterrestrial civilisations around. At least that’s the principle, but where are they?”, says Conway Morris. Why have aliens not popped up — except in Hollywood films such as ET and Independence Day — despite decades of eavesdropping with radio telescopes?

The astronomer Heather Couper said: “My main worry is that our technology is simply not up to the task. Earth came into existence four to five billion years ago, but the oldest stars are twice that age. They may have life, but that life may be far more advanced than we are.”

Others suggest aliens may have good reason not to give away their presence. Weak electromagnetic signals have been transmitted from Earth for nearly a century in the form of radio, television and other transmissions. By now some should have travelled 100 light years out into space, though they will be growing fainter and fainter.

If aliens have picked up footage of, say, Bernard Manning or Simon Cowell, let alone the Second World War, they may have decided to keep quiet. “They may be very like us,” said Conway Morris. “I’m not sure I’d answer the telephone.”

However, the most likely explanation, he admits, is that there simply are no alien civilisations out there, perhaps because planets with biospheres are very rare.

Dr Robert Massey of the Royal Astronomical Society, takes a similar view: “If there were thousands of civilisations out there, I think we would have detected something by now. But that doesn’t mean we shouldn’t try.”

Alien Census

http://www.sciam.com/article.cfm?id=how-much-intelligent-alien-life

February 10, 2009
Alien Census: Can We Estimate How Much Life Is Out There?
New study looks to tabulate the extent of intelligent extraterrestrial life
By John Matson

One day in 1950, nuclear physicist Enrico Fermi posed a question to a few colleagues he was lunching with at Los Alamos National Laboratory that would become known as the Fermi Paradox: If the Milky Way is indeed teeming with alien civilizations, as many theories suggest, where are they? Shouldn't we see evidence of their existence? Nearly 60 years later, the question remains just as vexing. After all, decades of searching for extraterrestrial radio signals or evidence of alien civilizations have come up empty.

Nevertheless, search for extraterrestrial intelligence (SETI) programs soldier on. And the hunt for any alien life, even in microbial form, is ramping up quickly with instruments probing Mars and other likely nearby candidates in greater detail and with the regular detection of new planets outside our solar system. In the absence of hard evidence for intelligent extraterrestrial life, some researchers have set out to estimate just how much might be out there. The hope is that they can justify the continuation of SETI searches or even refine them and thus up the odds of finding ET, perhaps someday rendering the Fermi Paradox moot.

In a recent paper published online by the International Journal of Astrobiology, graduate student Duncan Forgan of the Royal Observatory, Edinburgh, in Scotland set up a numerical model of the universe under different scenarios of biogenesis. His model relies on current observational knowledge of stars and planetary systems, as well as some assumptions about the viability of life and its ability to evolve into an advanced, intelligent form. If life can only arise under a narrow set of initial conditions, Forgan estimates there should be 361 advanced, stable civilizations in the Milky Way. If life can spread from one planet to another through biological molecules embedded in asteroids, though, the number jumps to nearly 38,000. (Even given a densely populated galaxy, Forgan notes, there is no guarantee of immediate mutual contact.)

Forgan's model makes use of the Monte Carlo method, by which the starting variables in a system are randomized over repeated simulations to allow for uncertainties in their values. By averaging the results from 100 such simulations, Forgan's analysis yields an estimate that accounts for variations in inputs.

But some in the field argue that estimates of the extent of extraterrestrial intelligence cannot carry any degree of accuracy, given the gaps in our knowledge. Such numerical estimates are "still subject to all the other uncertainties and all the other imponderables" regarding the origins of life, says planetary scientist Ian Crawford of Birkbeck College at the University of London. "We have to admit that we're hugely ignorant of many of the pieces of information that we would need to know before we could realistically estimate the prevalence of intelligent life elsewhere in the galaxy."

Mark Burchell, a professor of space sciences at the University of Kent in England, says that astronomically speaking, our knowledge base is fairly refined. "But the biological and social aspects of the equation remain speculative," he said in an e-mail. "As Forgan points out, we are limited to single-event observations (life on Earth) to make sweeping general predictions (life elsewhere)."

Forgan acknowledges that the analysis suffers from some uncertainties, stemming in part from a small and somewhat biased data set on planets outside the solar system. Some 300 planetary systems have been found since 1995, when the first planet orbiting a normal star other than the sun was discovered. But the detection methods employed in this effort tend to find planets that are quite large and hot. The European COROT satellite and NASA's forthcoming Kepler spacecraft, however, should be able to locate more Earth-like worlds in the coming years with dedicated, sensitive monitoring of dips in stellar brightness that occur when a planet passes in front of a star. Forgan says that "Earth-mass, rocky planets are still the best bet for habitability," so such discoveries would significantly affect his conclusions.

He also notes that the numbers, subject as they are to uncertainties, should not be considered the sole outcome of his paper. Simply refining models of where and when life should arise, he says, might improve SETI searches. "Searching for life in the galaxy is the ultimate needle in the haystack," Forgan says, and any guidance as to where and when to search for that needle should be useful.

But Crawford thinks such analyses won't affect the status quo. "We've got no option but to keep looking; there's nothing else we can do," he says. "All the SETI searches can do is what they've been doing for the last 40 years and keep listening."