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
Showing posts with label SETI. Show all posts
Showing posts with label SETI. Show all posts
Saturday, November 26, 2011
Friday, November 18, 2011
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.
Sunday, November 13, 2011
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
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
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