# Is this a potential planetary setup for the Alpha Centauri System?

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I originally posted this on the World Building SE, but I was suggested to post it here for a better answer. I am attempting to create a [semi]plausible star system in Alpha Centauri for a series. The system was originally intended to have 1 habitable planet per star, but after my first couple of attempts I noticed that it might be possible to get at least 3 planets to be habitable. The latest attempt actually shows 5 potentially habitable planets (2 of which are a binary[That is another SE question]). Ultimately, I would like this to be the case as it allows a much more diverse universe for the series.

## Attempt:

• aCen A Planets
• aCen B Planets

I don't have access to, or knowledge how to use, any form of software like Universe Sandbox. I have read several reports on planet orbits and I think I did an "ok" job with this.

My main concern is that the planets might orbit too closely. I have attempted to find a formula (that I could understand) that could aid in spacing the planets. The nearest I could manage is using the Mutual Hill Radii. There are conflicting reports where one says that 10 - 12 MHR (Delta-H) is good or a tightly packed system. Earth and Venus have around a 25 MHR value. One of the reports that I linked mentioned up to 25 MHR for aCenA, but it also shows several other numbers and after trying to comprehend everything my brain reached orbital velocity.

Question: Is the planetary spacing stable enough to host planets on Gigayear timescales? They don't necessarily need to be able to have spawned life, but they should be able to support life with little to no human intervention.

Note and Bonus, aCen V is a binary planet that orbits with a Semi-Major axis of 750,589km with an eccentricity of 0.01204. (There is an error in the image in Yellow that shows 148.623 and Eccentricity of 0.0910). The inclination should be 0 as both planets should be on the same plane. Last note: The Semi-Major Axis distance is in Megameters (1 million meters).

The only way to answer the question about stability is to do the integration, because this problem does not have an analytic solution. There are approximate solutions for the stability of two-planet systems (although these are based on a somewhat weaker constraint that allows the outermost object to escape to infinity) but they do not necessarily generalise to more planets. Furthermore, planetary systems tend to exhibit chaotic behaviour so you aren't going to get definitive answers even with an integration, because errors get introduced by the limited precision at which the calculations can be done.

You also need to bear in mind that the parameters you've listed in the table do not give sufficient information to set up an integration:

• You need the argument of pericentre ($$omega$$) and the longitude of the ascending node ($$Omega$$), which together with the inclination form a set of Euler angles describing the orbit's orientation in 3D space.
• You need the mean anomaly ($$M$$) or equivalent (e.g. mean longitude, $$lambda$$) to describe where the objects are along their orbits.
• You need to specify at what epoch these parameters are specified for.

The integration is going to be further complicated by the fact that it isn't sufficient to just simulate Alpha Centauri AB, you also have to take into account Proxima, which may perturb the orbits of the AB pair on gigayear timescales, and is also on such a wide orbit that you probably need to take the galactic tide into account and the unknown history of stellar encounters along the system's path through the galaxy.

I think you may have given each star too many planets. Alpha Centauri AB is a fairly close system, with a semimajor axis of 23 AU and an eccentricity of 0.52, which means the stars approach to within 11 AU of each other. Planets aren't stable unless the binary star surrounding them is more than 3-4 times more distant, so I think your outer planets may be in trouble. If these systems are space roughly like our own, I'd think each star could have no more than about five planets, and that would be stretching it.

## New Method for Planet Detectability in the Alpha Centauri System

Astronomers from Yale University have taken a fresh look at the nearby Alpha Centauri star system and found new ways to narrow the search for habitable planets there.

According to a study led by Professor Debra Fischer and graduate student Lily Zhao, there may be small, Earth-like planets in Alpha Centauri that have been overlooked. Meanwhile, the study ruled out the existence of a number of larger planets in the system that had popped up in previous models.

“The universe has told us the most common types of planets are small planets, and our study shows these are exactly the ones that are most likely to be orbiting Alpha Centauri A and B,” said Fischer, a leading expert on exoplanets who has devoted decades of research to the search for an Earth analog.

The new study appears in the Astronomical Journal. Co-authors are John Brewer and Matt Giguere of Yale and Bárbara Rojas-Ayala of Universidad Andrés Bello in Chile.

The Alpha Centauri system is located 1.3 parsecs (24.9 trillion miles) from Earth, making it our closest neighboring system. It has three stars: Centauri A, Centauri B, and Proxima Centauri. Last year, the discovery of an Earth-like planet orbiting Proxima Centauri set off a new wave of scientific and public interest in the system.

“Because Alpha Centauri is so close, it is our first stop outside our solar system,” Fischer said. “There’s almost certain to be small, rocky planets around Alpha Centauri A and B.”

The findings are based on data coming in from a new wave of more advanced spectrographic instruments at observatories located in Chile: CHIRON, a spectrograph built by Fischer’s team HARPS, built by a team from Geneva and UVES, part of the Very Large Telescope Array. “The precision of our instruments hasn’t been good enough, until now,” Fischer said.

The researchers set up a grid system for the Alpha Centauri system and asked, based on the spectrographic analysis, “If there was a small, rocky planet in the habitable zone, would we have been able to detect it?” Often, the answer came back: “No.”

Zhao, the study’s first author, determined that for Alpha Centauri A, there might still be orbiting planets that are smaller than 50 Earth masses. For Alpha Centauri B there might be orbiting planets than are smaller than 8 Earth masses for Proxima Centauri, there might be orbiting planets that are less than one-half of Earth’s mass.

In addition, the study eliminated the possibility of a number of larger planets. Zhao said this takes away the possibility of Jupiter-sized planets causing asteroids that might hit or change the orbits of smaller, Earth-like planets.

“This is a very green study in that it recycles existing data to draw new conclusions,” said Zhao. “By using the data in a different way, we are able to rule out large planets that could endanger small, habitable worlds and narrow down the search area for future investigations.”

This new information will help astronomers prioritize their efforts to detect additional planets in the system, the researchers said. Likewise, the continuing effort by Fischer and others to improve spectrographic technology will help identify and understand the composition of exoplanets.

The study was funded in part by NASA and the National Science Foundation.

Publication: Lily Zhao, et al., “Planet Detectability in the Alpha Centauri System,” AJ, 155, 24, 2017 doi:10.3847/1538-3881/aa9bea

## Astronomers Confirm Two Planets in Proxima Centauri System

Astronomers have finally confirmed the existence of two exoplanets — Proxima b and c — orbiting Proxima Centauri, the Sun’s closest stellar neighbor and one of the best-studied low-mass stars.

This artist’s impression shows Proxima b orbiting Proxima Centauri, which at only 4.23 light-years is the closest star to our Solar System. The double star Alpha Centauri AB also appears in the image between the exoplanet and Proxima itself. Image credit: M. Kornmesser / ESO.

Proxima Centauri, the smallest member of the Alpha Centauri system, is an M5.5-type star located 4.244 light-years away in the southern constellation of Centaurus.

The star has a measured radius of 14% the radius of the Sun, a mass of about 12% solar, and an effective temperature of only around 3,050 K (2,777 degrees Celsius, or 5,031 degrees Fahrenheit).

Proxima Centauri is 1,000 times less luminous than the Sun, which even at its close distance makes it invisible to the naked eye.

It has a very slow rotation of 83 days and a long-term activity cycle with a period of approximately 7 years. Its habitable zone ranges from distances of 0.05 to 0.1 AU.

The Earth-mass planet Proxima b was first discovered in 2016 by Queen Mary University of London astronomer Dr. Guillem Anglada-Escudé and co-authors.

The planet sits within Proxima Centauri’s habitable zone, where liquid water could theoretically exist on the surface.

“Confirming the existence of Proxima b was an important task, and it’s one of the most interesting planets known in the solar neighborhood,” said Dr. Alejandro Suarez Mascareño, an astronomer at the Instituto de Astrofísica de Canarias and the Universidad de La Laguna and the lead author of a paper to be published in the journal Astronomy & Astrophysics.

Dr. Mascareño and colleagues confirmed the presence of Proxima b using independent measurements obtained with the ESPRESSO (Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations), a high-resolution spectrograph installed on ESO’s Very Large Telescope.

Their results show that the minimum mass of Proxima b is 1.17 times that of Earth (the previous estimate was 1.3 Earth masses) and that it orbits around its star in only 11.2 days.

“ESPRESSO made it possible to measure the mass of the planet with a precision of over one-tenth of the mass of Earth. It’s completely unheard of,” said Nobel laureate Michel Mayor, professor emeritus at the University of Geneva and the ‘architect’ of all ESPRESSO-type instruments.

An artist’s impression of the Proxima Centauri system. Image credit: Lorenzo Santinelli.

Earlier this year, Dr. Mario Damasso from Italy’s National Institute for Astrophysics and colleagues announced they might have found a super-Earth exoplanet around Proxima Centauri.

The astronomers used radial velocity observations to deduce the candidate planet — named Proxima c — orbits the star every 1,907 days at distance of 1.5 AU. Still, its existence was far from certain.

In a separate study, Dr. George Benedict and Dr. Barbara McArthur from McDonald Observatory and the University of Texas at Austin revisited the 25-year-old Hubble data for Proxima Centauri.

“When we originally studied Proxima Centauri in the 1990s, we only checked for planets with orbital periods of 1,000 Earth days or fewer. We found none,” Dr. Benedict said.

“We now revisited that data to check for signs of a planet with a longer orbital period.”

Indeed, the team found a planet with an orbital period of about 1,907 days in the archival Hubble data.

This was an independent confirmation of the existence of Proxima c.

These images, taken by the SPHERE instrument on ESO’s Very Large Telescope, show the candidate optical counterparts of Proxima c (red circles) background stars are also shown. Image credit: Gratton et al, arXiv: 2004.06685.

Shortly afterward, Dr. Raffaele Gratton of INAF and colleagues published images of the planet at several points along its orbit that they had made with the SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research) instrument on ESO’s Very Large Telescope.

Dr. Benedict and Dr. McArthur then combined the findings of all three studies: their Hubble astrometry, Dr. Damasso’s radial velocity studies, and Dr. Gratton’s images to refine the mass of Proxima c.

They found that the planet is about 7 times as massive as Earth.

“Basically, this is a story of how old data can be very useful when you get new information,” Dr. Benedict said.

“It’s also a story of how hard it is to retire if you’re an astronomer, because this is fun stuff to do!”

Dr. Benedict and Dr. McArthur presented their results June 2 at the 236th Meeting of the American Astronomical Society (AAS).

A paper by Dr. Gratton’s team will be published in the journal Astronomy & Astrophysics.

A. Suárez Mascareño et al. 2020. Revisiting Proxima with ESPRESSO. A&A, in press arXiv: 2005.12114

G.F. Benedict & B.E. McArthur. 2020. Old Dog, Old Tricks, Old Data – A Mass for Proxima Cen c. AAS 236, abstract # 206.04

R. Gratton et al. 2020. Searching for the near infrared counterpart of Proxima c using multi-epoch high contrast SPHERE data at VLT. A&A, in press arXiv: 2004.06685

## First Planet Discovered in Alpha Centauri System

Using more than four years of data, astronomers using the HARPS instrument on the 3.6-meter telescope at ESO’s (European Southern Observatory) La Silla Observatory in Chile have reported the discovery of a slightly larger than Earth-mass planet orbiting the star Alpha Centauri B. This is the first discovery of a planet in our closest neighbor system of stars, and the least massive exoplanet ever discovered around a star like the Sun. I wanted to share with you some thoughts and insights by Yale astronomer Debra Fischer who leads another Alpha Centauri planet search that is partially supported by The Planetary Society. But first, here is a little more on the discovery (and if you are looking for a primer on exoplanet hunting, check out our online astronomy course lecture on the subject).

First planet discovered orbiting Alpha Centauri B (artist's concept) Artist’s impression of the first planet discovered orbiting the star Alpha Centauri B, a member of the triple star system that is the closest to Earth. The planet was found in 2012 with the HARPS spectrograph on the 3.6-m telescope at ESO’s La Silla Observatory in Chile. Image: ESO/L. Calçada/N. Risinger (skysurvey.org)

The planet would be crispy, toasty hot (not a technical term), at least on the side facing its parent star, since it orbits only 6 million kilometers from its parent star in a 3.2 day orbit. For comparison, the closest point to the Sun in Mercury’s elliptical orbit is 46 million kilometers, and Mercury has an 88 day orbit.

The European discovery team’s research was published today in the journal Nature. The lead author is Xavier Dumusque (Observatoire de Genève, Switzerland Centro de Astrofisica da Universidade do Porto, Portugal).

The Alpha Centauri system, a little over 4 light years away, consists of three stars labeled A, B, and C from brightest to dimmest. The two brightest are roughly Sun-like, whereas the third, also known as Proxima Centauri because it is the closest to Earth, is a red dwarf much farther out in the system. The planet discovery was around Alpha Centauri B (AlphaCenB, or aCenB or Scooter [not really]), which is somewhat smaller and less bright than the Sun.

The Planetary Society is supporting another Alpha Centauri exoplanet search, led by Debra Fischer at Yale University (read about it here and/or listen to Debra on Planetary Radio here). Debra shared with me her thoughts and some insights on the Alpha Cen planet discovery, as well as how it relates to their search:

“The HARPS team called me a week ago to let me know about their result and we've been analyzing our data and running simulations to test the detectability of this tiny signal. Our best data set for aCenB begins in June 2012, when we completed some stability upgrades to the new spectrograph (CHIRON) that we built for the 1.5-m CTIO telescope (with NSF MRI funding). Our precision since the upgrade matches the HARPS precision, but yields a 5-month string of data compared to the 5-year time baseline of data from HARPS.

There is not a more exciting result for an individual star, even with the long line of spectacular results from the last 2 decades. The indication that our nearest neighbor has rocky planets is incredible. Furthermore, statistical results from the NASA Kepler mission suggest that where there is one, there are usually several rocky planets. This leaves open the possibility of a terrestrial planet in the habitable zone - in fact, I think this strengthens the speculative possibility of a habitable world in the alpha Cen system.

The Geneva team has done something very difficult, but it's an approach that I've advocated for the past few years: they are digging into their data to remove signals that arise from the surface of the star, leaving behind the whiff of a residual signal - a mere 0.5 m/s - induced by a prospective planet. The team is extremely careful and no one wants to be wrong about such a high profile result. I have no doubt that they have carried out every reasonable test of their data before making this announcement. Nevertheless, because these corrections essentially constitute a new approach, confirmation is critical. We are in an excellent position to follow-up, but that will likely require an intensive search over the prospective orbital period of 3.24d when the star rises again in January 2013.”

The first discovery of another world, much less an Earth-sized world around a star in the closest star system to Earth is a profound one, and one that is all the more exciting because, it may portend future discoveries there of planets that are even more Earth-like. Even around our nearest neighbors, the search is not easy, but the results may yield planets we can study in more depth because of their “closeness.” Someday, Alpha Centauri planets could be the first extra-solar system destination for advanced future robotic and, maybe someday, human emissaries.

## Scientists Have Potentially Discovered a New Life-supporting Planet

If proven to exist, the planet might be four to five times larger than Earth.

The search for life in space just took a big leap forward. Researchers working on the New Earths in the Alpha Centauri Region (NEAR) project, funded by entrepreneur Yuri Milner&aposs Breakthrough Initiatives, have potentially discovered a new planet in the habitable zone of the nearby star Alpha Centauri A, located 4.37 light-years from Earth. Their report was published in the Nature Communications journal this week.

In an image taken of the star via the European Southern Observatory&aposs (ESO) Very Large Telescope (VLT) in Chile, the team spotted a separate glowing object. They suspect it might be a planet — one that&aposs four to five times larger than Earth, or roughly the size of Neptune. It&aposs located between one to two astronomical units (AU) from its star (one AU is the distance from the Earth to the sun), putting the planet in the habitable zone, where water might be able to form to support life.

Particularly intriguing to scientists is that Alpha Centauri A is a binary star with Alpha Centauri B — many theorized that planets wouldn&apost be able to form in such a binary system. However, the planet is only a planet candidate for now, as the research team needs more data to verify its existence.

"We were amazed to find a signal in our data," the study&aposs coauthor Kevin Wagner said in a statement. "While the detection meets every criteria for what a planet would look like, alternative explanations — such as dust orbiting within the habitable zone or simply an instrumental artifact of unknown origin — have to be ruled out."

If it does turn out to be a planet, it wouldn&apost be too surprising. In 2016, scientists discovered a potentially habitable planet orbiting the third star in the Alpha Centauri system, Proxima Centauri. (This star also made headlines last year when astronomers discovered an unusual radio signal coming from its vicinity.)

Interestingly, the most exciting part of this discovery is not necessarily the planet candidate itself — it&aposs how scientists have spotted it. Previously, astronomers could only determine the existence of exoplanets by watching the behavior of stars. If they dim during observations, planets are likely passing in front of them if they wobble, it&aposs likely due to a nearby planet&aposs gravitational pull.

The NEAR team&aposs new observation, however, marks the first time that scientists were able to directly image (that is, essentially photograph) the habitable zone of a nearby star, opening up a whole new world of possibilities when it comes to searching for exoplanets.

"Whether this thing is real is, to me, almost secondary," study coauthor Olivier Guyon told Scientific American. "Because either way it shows we&aposre clearly opening a new era in the history of astronomy where, finally, after more than 20 years of hard work, we can at last perform direct imaging of another star&aposs habitable zone. This is the &aposgame on&apos moment for the field."

So, even if this planet candidate turns out to be a speck of dust or a mechanical glitch, there&aposs still plenty to be excited about — at least if you&aposre an astronomer.

## The TOLIMAN Technology

The TOLIMAN mission is designed to use astrometry by means of a diffractive pupil aperture mask that in effect leverages the distortions of the optical system to produce a ‘ruler’ that can detect the changes in position that flag an Earth-mass planet in the Alpha Centauri system. Tuthill’s colleague Céline Bœhm presented the work at the recent Breakthrough Discuss online.

In TOLIMAN, we actually have an acronym — Telescope for Orbit Locus Interferometric Monitoring of our Astronomical Neighborhood — but at least it’s one that’s applicable to the system under study. According to Boehm, there are certain advantages to working with nearby binaries. Astrometry normally uses field stars (stars in the same field as the object being studied) as references, making larger apertures an essential given the faintness of many of these reference points and their distance from the target star, and requiring a wide field of view.

But a bright binary companion 4 arcseconds away, as we find at Alpha Centauri, resolves the problem. Now a small aperture telescope can come into play because we have no need for field stars. The TOLIMAN concept puts a diffractive ‘pupil’ in front of the optics that spreads the starlight out over many pixels, a diffraction caused by features embedded in the pupil. Here stability is at play: We’re trying to eliminate minute imperfections and mechanical drifts in the optical surfaces that can create instabilities that compromise the underlying signal. The pupil mask prevents the detector from becoming saturated and reduces noise levels in the signal.

The astrometric ‘ruler’ used to measure the star’s position is thus created by the light of the stars themselves. The diffraction pattern cast by the pupil positions a reference grid onto the detector plane, which registers precise stellar locations. As a 2018 paper on the mission puts it: “Drifts in the optical system therefore cause identical displacements of both the object and the ruler being used to measure it, and so the data are immune to a large class of errors that beset other precision astrometric experiments.”

Narrow-angle astrometry, where the reference star is extremely close, makes for greater precision than wide-angle astrometry, and angular deviations on the sky are larger. Boehm makes the case that TOLIMAN’s diffractive pupil technology should be effective at finding Earth analogs around Centauri A and B, with a more advanced mission (TOLIMAN+) capable of finding rocky worlds around secondary targets 61 Cygni and 70 Ophiuchi.

Image: This is from Figure 3 of the online description of TOLIMAN referenced above. Caption: Left: pupil plane for TOLIMAN diffractive-aperture telescope. Light is only collected in the 10 elliptical patches (the remainder of the pupil is opaque in this conceptual illustration, although our flight design will employ phase steps which do not waste starlight). Middle: The simulated image observing a point-source star with this pupil. The region surrounding the star can be seen to be filled with a complex pattern of interference fringes, comprising our diffractive astrometric grid. Right: A simulated image of the Alpha Cen binary star as observed by TOLIMAN. Credit: Tuthill et al.

## The Alpha Centaurian race.

Another extraterrestrial race that appears to be playing a significant role in human affairs is from the Alpha Centauri star system. Alex Collier claims the Alpha Centaurians are one of the races visiting the Earth. [127] The most compelling testimony supporting the presence of the Alpha Centaurians is Elizabeth Klarer who had high level responsibities within the British military to monitor UFO reports. [128] Klarer was apparently contacted by the Alpha Centaurians and eventually taken to Alpha Centauri for a few months to have a child fathered by the Alpha Centaurian, Akon. Klarer’s description of the Alpha Centaurians gives a vivid account of how technology can be wisely used to benefit both humanity and the ecosystem. The Alpha Centaurians were argued to be benevolent and genuinely desiring to assist humanity in dealing with its evolution.

An alleged former employee of the covert Montauk and Philadelphia projects, Al Bielek, discussed a number of extraterrestrials including the Alpha Centaurians. Bielek’s testimony is perhaps one of the most bizarre and controversial cases in UFO research yet his testimony is coherent and consistent, and according to an independent investigator, John Quinn, Bielek is very credible and there is much evidence to support his claims. [129] The Alpha Centaurians, according to Bielek, apparently provide a form of sanctuary and protection to humans that desire assistance in dealing with the repressive polices of the shadow government. Bielek stated the nature of this agreement with the Alpha Centaurians in an interview:

AB [Al Bielek].There are shuttles regularly from this planet to Alpha Centauri 4 which by agreement is a safe haven for people wanted by the U.S. Government. There's a treaty. It takes about 12 hours to get them. Apparently they took all of their family which meant sisters, brothers, father, mother, whatever, with them. As far as I know they're still there.

SS [questioner]: Who runs the shuttle?

AB: Presumably the Alpha Centauri Government, but I don't know. But it's on a regular basis twice a week. The landing point I have no idea where it is. Of course they guard it secret.

SS: What is their body form like?

AR: Alpha Centauri? Like humans, exactly the same. There's a much lower population on their planet. They're not overpopulated. They're an advanced civilization, a little ahead of us - not a great deal, but somewhat ahead of us. They don't like things like government headbashing and that sort of thing and they way they treat some of the government agents they no longer have any use for or whatever, if they are approached, and I don't know how it's done, if they are approached and asked for asylum, if they issue the card, you just get on the shuttle and that's it, you're there. Beyond that I don't know. I haven't seen them since. [130]

This role of providing sanctuary to humans threatened by the shadow government indicates that the Alpha Centaurians are very interested in social justice and helping in the transition of Earth towards a more trusting and nurturing global society. This is a theme elaborated upon in the following telepathic communication from an independent source: “Those from [Alpha] Centaurus have an open society, a trusting and loving one, so they would be useful to you as you begin to design the social rules for an alternative to a combative or competitive social structure.” [131] The main activity of the Alpha Centaurians can therefore be inferred as promoting social justice and human freedom, and the responsible use of advanced technology. The Global solutions that can be promoted by the Alpha Centaurians include social justice at a global level, creating zones or peace or peace sanctuaries, human rights and sustainable development.

Introduction and Interview by Stuart Bush

Transcribed and Edited by Noel Huntley, Los Angeles, California

She stayed on the planet Meton for four months where she gave birth to and reared her space child, Ayling.

Particular interest was shown in Elizabeth's experiences by the British Ministry of Defense and they announced that UFOs do exist and are now official.

Elizabeth's story has attracted the attention of many countries, in particular America, Britain and Russia.

In 1975 she was given a standing ovation at the 11th International Congress for UFO Research in Germany.

In 1983 she addressed the House of Lords, in England and her paper was also read at the United Nations.

Elizabeth Klarer was born in 1910 in Mooi River, Natal, where she grew up on a farm and soon learned to understand the Zulus very well. She was trained as a meteorologist at Cambridge, England. She later went to Trinity College, London, to study music, where she obtained a degree. She is also a pilot, and learned to fly the DeHaviland plane. During World War II she was employed by the South African Air Force Intelligence and during operations did work for the Royal Air Force decoding German communications. She was also trained to observe UFOs for the South African Air Force UFO Division. She has a son David, a daughter, Marilyn, who is now a medical specialist, and another son, Ayling

an astrophysicist living on another planet, which we will cover shortly.

Her fascinating story began at the age of seven when a flying saucer visited her near her home. Telepathic communication between Elizabeth and Akon, who was a crew member and scientist of the spacecraft, occurred several times. In April, 1956, on Flying Saucer Hill at Rosetta, Natal, the crew revealed themselves and Elizabeth Klarer was taken up into space and into the vintage mother ship. In November, 1957, on the high plateau of Cathkin Peak, in Drakensberg, Elizabeth Klarer entered the spacecraft to meet her new-found lover Akon.

During the next eight and a half months she endured harassment, especially from American intelligence forces, and on one occasion she was almost kidnapped by the Russians who wanted to capture the future space child. She was eventually taken by Akon to another solar system, our nearest neighbour, Alpha Centauri. There she stayed on the planet Meton for four months where she gave birth to and reared her space child, Ayling. Owing to the vibrations of the magnetic field being different on Meton, her heart was unable to adjust to the new pressures, and she was forced to return to Earth. Contact has been maintained and Akon and her son, Ayling, have both appeared to her visually in a projected holographic image.

In 1984 particular interest was shown in Elizabeth's experiences by the British Ministry of Defense and they announced that UFOs do exist and are now official. Elizabeth's story has attractd the attention of many countries, in particular, America, Britain and Russia. In 1975 she was given a standing ovation at the 11th International Congress for UFO Research in Germany. She was applauded by a group of scientists representing 22 nations where she gave a speech about the secrets of light. In 1983, she addressed the house of Lords in England, and her paper was also read at the United Nations. A few years ago she traveled to Switzerland to appear on a TV show. She has written a book entitled "Beyond the Light Barrier," and has now completed a second one, "The Gravity Files." (Editors Note: This book has not been published as far as we know.)

Interview With Elizabeth Klarer By Stuart Bush

Stuart Bush: Could you describe the flying saucer you flew in?
Elizabeth Klarer: She was perfectly circular, about 60 feet in diameter, with a very large hull and a flattish dome in the center with portholes around the dome. There were sets of three portholes encircling the entire dome and she had a silvery sheen about her. This wasn't a reflection from the sunlight, it was her own glow. It came directly from the skin of the ship and when the power was switched on the whole ship glowed and would set up this field differential around her, which, of course, she moves within. Inside she is very, very beautiful simple but completely beautiful, and the colors so lovely. The entire floor is covered with a rose-red type of carpeting

very soft and very springy to walk on. The walls change color when the power system is on they change from blue to green.
S.B.: Is there a functional reason for this?
E.K.: Yes, in harmonic interaction you are not only going to have the color in the electromagnetic wavelength of the universe, which, of course, is the whole basis of her power system, but the colors come in as well and the different movements, particularly when she is speeding through the atmosphere. These starships vary in size. The mother ships are very much larger and do not land. The ships can travel instantaneously from one place to another.
S.B.: What was the number of the crew in the ship you traveled in and what were their duties?
E.K.: Two, and they were both scientists. Both were astrophysicists but one was also a very great botanist which was a needed ability in understanding the flora and fauna of planets for their protection and in the preparation of planets for human habitation. This is a continuous activity.
S.B.: Tell us something about the outside construction of the ship.
E.K.: The ship is created in space from pure light energy into substance, and it takes naturally the celestial form. They then bring her to the surface of the planet and construct the interior. But the whole skin of the ship is created in space in order that this atomic structure of the skin of the ship is conducive to energizing. That's how you get the power and the different colors.
S.B.: I s the material metal?
E.K. No, it's not like a metal at all. It is more like a porcelain. It is made of an atomic substance from pure light energy which is the ultimate particle.
S.B.: How long does it take to create the ship?
E.K.: To create the complete shell, no matter what the size, you have to have the harmonic interaction of the measurement of that circle it has to be perfectly in harmony. It takes, in earth time, about 15 minutes to create. And it is created and not constructed, from natural cosmic energy. Then when they take her to the surface of the planet to complete the interior, in earth time, it takes about a couple of weeks.
S.B.: Are they armed?
E.K.: No, all they have is a deflecting ray as a form of protection which will keep any hostile craft at bay and immobilize them. The shield effect completely protects her

from bullets, a missile or atomic bomb. The magnetic field is so tremendous.
S.B.: Is it vulnerable then, when it is at rest?
E.K.: No, there is an automatic switch. The approach of any intrusion causes the field to come on automatically.
S.B.: Could you tell us something about the vintage mother ship?
E.K.: She is a vast carriership with about 24 small landing craft each of which carry a crew of two people. The mother ship hovers about 1000 miles away in space and releases one of these landing craft to the surface of the planet. They accommodate at least 5000 people

including women and children. They are completely self-contained with an abundance of everything. They grow their own food on the ship using their own means of irradiation sunlight is not necessary.
S.B.: How do you view outside the ship?
E.K.: The ship is completely enclosed but there are portholes which can be opened, and also inside there is the viewing lens which enables you to see outside in all directions. This device not only can see through barriers such as into cellars of buildings but can reveal the finest detail, such as beads on a necklace worn by a person on the ground. And similarly for sound.
S.B.: Are all the crew from Meton?
E.K.: They are from the one civilization

of seven planets. But they are preparing other planets for human habitation in the system of Vega. Vega is a young blue-white waxing star.
S.B.: Could you tell me how the people compare with humans on Earth?
E.K.: They are human but taller, better looking, more considerate and gentle not aggressive and violent. They dress and eat more simply and are still young at an age of 2000 years of Earth time. Their star is not so violent. Our sun is a variable and produces rather harsh radiation which affects the skin, ages one, and can be dangerous. They wear simpler and less clothing made out of silk. Silk is beautiful and comfortable next to the skin. Everything is free and you can pick out your own clothes at a silk farm. There is an abundance of everything. No money or barter system is necessary.
S.B.: What was the planet itself like which you visited?
E.K.: It is similar in size to Earth, a little larger, covered with vast seas, and the lands are islands, not continents. Climate is beautiful, under control, and in fact, is really a utopia. They have everything they want. They are not only thousands of years ahead technologically from us, but are also spiritually very advanced.
S.B.: Could you describe the social systems on Meton?
E.K.: There are no politics, law, or the monetary system. Medicine is a scientific activity and not required for health since they are all in perfect health. Their way of thinking is quite different from what most people over here would understand. They are a loving, gentle and constructive people. Everyone industriously does their work which they like doing most. There is no need for law there is no crime or police. Everyone is free and has a code of ethics. They constantly create beauty around them and in general there is complete harmony. Their homes are lovely. You can see from the inside out the material is transparent one way. Regarding pets, they love their birds, in particular, and there is telepathic communication with them. Predatory animals are kept on a different planet.
S.B.: What about their educational system?
E.K.: They don't have schools or universities. Their education is completely visual

all done by what is called an electric mirage. They have a little phial about three inches long and they insert it into a niche in their home or the wall of a spaceship. A 3D scene fills the room

an advanced form of a holograph. There are no books. They travel a great deal. The young children are taken around the galaxy so they can learn from experience. They can use the electric mirage to go back to a former time in their history. They could, for instance, view our planet at the time of the dinosaurs. They have beautiful paintings and create lovely music

harmonic music and very uplifting spiritually, which relate to the harmonic music of the galaxy.
They communicate by means of telepathy and educational concepts can get transferred this way. They are capable of thinking in terms of the basic concepts not dependent on language

they perceive the feelingness behind words. There is no problem in the learning of languages such as any of those on Earth.
S.B.: What shape was the mother ship?
E.K.: She was more of a cigar shape with blunt ends and angles depending on the light effect. From certain angles she could look circular and may be five miles in length. These are city ships containing everything needed

trees and flowers, lakes, beautiful living quarters. Families are raised on the ships.
Some spacecrafts which land and are seen by people, are only holographs. This is part of the conditioning process so that earthman will become used to the idea of the existence of extraterrestrials.
S.B.: And what is this system they have of harmonic mathematics, and are there any books explaining this?
E.K.: Yes, I have books on it, written by professor William Conner from the U.S.A. I have his treaties on harmonic mathematics which explains the whole process. He's also done this with respect to my book "Beyond The Light Barrier." He has related the various figures, distance of Meton from Earth, Akon's age, etc. to harmonic mathematics it's all there.
S.B.: Returning to the educational aspects, if there are no books, how is information imparted?
E.K.: It is done from mind to mind, telepathy ship works

how she is using the power system of the universe. You have to understand the physics of the power system. The physical body could go but not the mind. This knowledge was imparted to me by Akon. He just put his hand on my forehead and told me to relax and think and know exactly how the spaceship is utilizing the cosmic power to go from this system to the home system. His hand on my forehead enabled me to relax completely and understand how the ship was using the matrix of space to go through the ether. I had to be in complete harmonic relationship with the spaceship to go through the light barrier.
S.B.: What is the woman's life like on Meton?
E.K.: There are no chores as we have on earth. It is all done with a light ray. For example, a beam of light will bring you your food on a tray. Families are larger

most families have about seven children. You could have children while thousands of years old, as there is no problem with age. They use a natural contraceptive a type of vegetable which they put in their food. There is no marriage and divorce. They simply find their mate and stay together for life. If there is an accident and a loss of life, the person simply reincarnates and comes back to their same mate.
S.B.: What about the gravity belts? Did you use one?
E.K.: Yes, I used one to go upstairs. There are just three knobs for starting, control and direction.
S.B.: You mentioned seven planets. What are the names of the others?
E.K.: They don't have names, just harmonic numbers. Akon gave me the name Meton for identification purposes.
S.B.: How important is time to them and how do they measure it?
E.K.: They don't measure time at all. Time varies too much in any case. With their triplet star system, they do not measure time as we do here, with night and day, since they don't have night and day. When the smaller star, Proxima sets, the other two rise so there is never any night.
S.B.: What are their sleeping patterns?
E.K.: They depend on sleep

it is a great health restorer. In terms of Earth time they would sleep nine hours.
S.B.: Regarding their eating habits, what are their views on how to eat?
E.K.: They don't cook, they eat the natural foods, vegetables, salads, etc. The only thing they heat, using electricity, are certain oat cakes, made of fresh whole oats, like bread. They are only heated briefly to bind them together. They never use chemical fertilizers for growing food.
S.B.: Why don't they have competitive sports on Meton?
E.K.: They don't think about it

it is not necessary for them. Earthman, when he is not involved with wars, etc., needs to release his aggression in sports and such competitive activities. The Meton people do not have this problem.
S.B.: Do they recognize creative aggression?
E.K.: Yes, one must have determination and drive to create, but it doesn't have to be aggressive!
S.B. What is their approach to health products? On Earth there is a growing enlightenment in this direction.
E.K.: Yes, well they eat the natural foods and know which contain the necessary ingredients for health. It is necessary to balance the chemical processes in one's food for proper utilization by the body. The important thing in growing natural foods is the soil to grow them in, and you cannot possibly, as you do here, use chemical fertilizers. They never use anything like that. They simply put back into the soil what they take out. They revitalize the soil by means of electricity, which is what lightning does. It brings the Nitrogen into the soil. This is why lightning and thunderstorms are so important, along with the light and radiation from the sun.
S.B.: So they would eat say, a raw potato?
E.K.: They do grow peas. They are a necessary source of protein, and they eat a lot of fiber, as this is vital. They have natural vegetables and fruits, which are scientifically improved and enlarged. For example, an apricot, which would be the size of an apple, would be enough for one meal. It would have all the vitamins in it you would need, because apricots are a tremendously nutritious source of food and have a rejuvenating effect on the body.
S.B.: Now, can you say anything about planet Selo, which was visited by Hal Wilcox (UFO contactee), and which is about 600 years ahead of us, yet is of the same Alpha Centauri system as Meton, which is how many more years ahead of us?
S.B.: How is there a planet (Selo) in the same system so far behind?
E.K.: Planets vary. You have planets in certain stages of advancement, and planet Selo is closer to two major components of Alpha Centauri. These are the two larger stars, and these rotate about each other. Selo is closer to them in that vicinity, therefore Selo would receive greater intensity of radiation from these double stars. Proxima Centauri is very much farther away, but it still makes up a triplet system, which is known as Alpha Centauri, and Akon's home planet is in orbit about Proxima Centauri. There are seven planets there altogether (around Proxima Centauri) which is a star about the same size as our sun. So you have a different radiation output, which has a great effect on civilizations that exist on the orbiting planets. Radiation has a vast effect on the brain or mind, and consequently on development.
S.B.: As I understand it now, Selo has two suns and Meton has three suns, yet they are both in the same system. Does it mean this third sun is in a higher dimension?
E.K.: Meton, my home planet, only has one sun, and Selo has two suns, so that makes up the triplet system of three suns!
S.B.: But I gather that there is no nighttime on Meton!
E.K.: That's right. Because when Proxima Centauri sets in the planetary rotation, the two larger stars rise, and they are so big that their light is cast very far afield, and naturally Meton, being in this triplet system, gets the light from these two larger stars, but not the intensified radiation, because of the distance. You see, the two larger stars are young, waxing stars, and they give out intensified radiation, while Proxima, the third star, is smaller and a middleaged star, so it gives out a modified, highly intensified vibratory radiation, which has a very different effect in the formation and advancement of a civilization, because it does affect the brain.
S.B.: I would presume then that Meton is in a higher dimension than Selo.
E.K.: Yes, in a higher vibratory rates and very much farther advanced, and has a civilization which occupies all seven planets in that system. (Ed. But it is in the same physical dimension.)
S.B.: To get back to the mother ships or city ships (some cigar-shaped, and five miles long!), how were these constructed

out in space?
E.K.: Constructed in space, yes, but we don't talk about construction, we say they are created. They were created in the atmosphere of the planet. All the components were ferried up to her, to be put together in space. This was done more than 65 million years ago. It goes right back in the history of ths solar system, when Venus was alive. (Ed.

habitable in the third dimension.) Scienists of Venus in those days detected that the sun was a variable star (Ed.

irregular frequency), so they prepared to move out into space, and they built the vast mother ships to ferry all the people and as much as possible of the flora and fauna away from the planet to the Earth, which was the nearest neighbor.
S.B.: To get back to the mother ships or city ships (some cigar-shaped, and five miles long!), how were these constructed

out in space?
E.K.: Constructed in space, yes, but we don't talk about construction, we say they are created. They were created in the atmosphere of the planet. All the components were ferried up to her, to be put together in space. This was done more than 65 million years ago. It goes right back in the history of this solar system, when Venus was alive. (Ed.

habitable in the third dimension.) Scientists of Venus in those days detected that the sun was a variable star (Ed.

irregular frequency), so they prepared to move out into space, and they built the vast mother ships to ferry all the people and as much as possible of the flora and fauna away from the planet to the Earth, which was the nearest neighbor.The scientists recognized the Sun was a visible star, with maximum and minimum periods of sunspot cycles, which happens to this day, but at certain epochs in time it expands. Now the Sun is expanding and contracting all the time. It is pulsating like a heart, but at certain epochs it expands out more, in intensified radiation.Now this is what happened to Venus, and being closer to the Sun her seas had dried out, and what little fauna remained (and all the flora) were destroyed. And then of course the dinosaurs, which had dominated the Earth, were also destroyed through the intensified radiation. Thus the great civilization from Venus, which we call the mother planet, was able to get away from Venus, and landed on earth and the moon, as way-stations.So there we have the beginning of highlyintelligent human life on this planet because we were fathered by men from outer space. Certainly not descended from the primates of this planet, but in fact from cromagnon, an advanced human being, who created the great civilization of Atlantis, which, of course, was eventually destroyed.The civilization from Venus decided to leave Earth owing to the harsh nature of the variable Sun and move to a neighboring system that was more conducive to their way of life and thinking. They discovered Proxima Centauri, which was a star similar to the Sun only much older and therefore a stable star. They moved to Meton which is now the home planet because it is very similar to the mother planet, Venus, in atmospheric conditions, distance from the star and also, the more important of all, the higher vibratory rates, which is more compatible to an advanced civilization and consciousness. They had bases on the Moon, Mars and Earth which they still visit.The Venus people left a section of their civilization here on Earth to look after the planet and advance the mentality and consciousness of the indigenous people of this planet, which they are in the process of doing.
S.B.: Did they have anything to do with the age of Lemuria and Atlantis?
E.K.: Yes, definitely with Atlantis. Atlantis was, of course, their main base and they also had a base in South America. Some of the Incas are descendents of the space people. Now, in the region of the Andes there used to be a very tall, fair race of people, many redheads, and these people were from Venus. They remained there until the great upheavals of Atlantis, which resulted in the Andes being pushed up by volcanic eruptions and with the volcanic evolution of the planet generally. So what was once a very fertile area became barren and mountainous, as it is to this day. But you still have certain buildings that remain, and also under the sea. Some of the pyramids still remain in Central America and these are the most important ones because they are very beautiful and vast, and there is one pyramid which has just been uncovered by archeologists who thought it was a mountain. The Spaniards built a cathedral on the top. It was covered in trees and grass, and the excavations are now revealing a pyramid.
S.B.: Where do the rest of the Earth people come from if only a small portion came from Venus?
E.K.: The majority of people here on Earth are indigenous, with a certain percentage from the home planet Venus who had stayed here when the main civilization moved out from Venus before going on to Proxima Centauri. They remained to look after the planet, and also for educational purposes for the native people, which of course is being done to this day.So we're here to inform people of the truth of their origin. Also to bring Venus back to life by feeding the atmosphere with algae, which creates the storms, the rain and the lightning, the volcanic eruptions, and the life. And also to form the seas again, because Venus was originally covered with vast seas, as is Meton. That is why Akon's civilization moved out from earth to Meton because it is very similar to what Venus was in the past islands and seas, with thick atmosphere, which filters the radiation, and above all has a higher vibratory rate for the advancement of a higher civilization, and particularly for the advancement of a consciousness into the fourth dimension.They have also come back to create bases on the Moon and Mars. They can bring back to life Mars as well as Venus, and this they plan to do since their main work throughout the galaxy is to prepare star systems for human habitation.
S.B.: How would this tie in with the information that the Sun is dying?
E.K.: The Sun is dying, but we don't talk about age, it is simply a metamorphosis. It is becoming cooler so something has to be done about it. It is going to be a double star system since Jupiter is a forming star. Jupiter will have a star burst in the very near future and we'll then have two stars in the skies of Earth. As the Sun cools down, Jupiter will heat up.
S.B.: How long do you think the Earth people have been in existence?
E.K.: The indigenous people of Earth go back to the time of the dinosaurs. Before the demise of the dinosaurs there was a very small colony of human kind, as there was also a very small colony of mammals, and they were not affected by the intensified radiation because they took refuge in caves and escaped the radiation by going underground. This was instinctive, and it was the same with the other mammals. But the giant creatures had nowhere to escape from the intensified radiation. The ultraviolet destroyed the vegetation so they had no food and became extinct. The mammals were intelligent enough to go underground and then lived on other life. Now many of our race today are descendents of these people from Venus. Generally they are not conscious of the fact that they are here to advance and educate the indigenous peoples of this planet, but many have had a race memory which has been activated by certain events

material in a book or seeing a spaceship in the sky. They have suddenly realized this is their purpose and that this is what their life is all about and they are here for a reason.
S.B.: To come back to Akron's spacecraft, when he visited you did his craft create the thunderstorms?
E.K.: Not always

sometimes. This is a very interesting question. The thunderstorm, particularly the hailstorm, which I described in my book, was quite natural. But it has happened in the past and very recently that his spaceship has created thunderstorms. This is due to the fact that when she come into the condensation level of our atmosphere the heat field around the ship condenses the molecules of the atmosphere into cloud and the result is that the gravity field retains the cloud around the ship, spinning it around in its lines of force

## Technosignatures: Looking to Planetary Atmospheres

While we often think about so-called Dysonian SETI, which looks for signatures of technology in our astronomical data, as a search for Dyson spheres, the parameter space it defines is getting to be quite wide. A technosignature has to be both observable as well as unique, to distinguish it from natural phenomena. Scientists working this aspect of SETI have considered not just waste heat (a number of searches for distinctive infrared signatures of Dyson spheres have been run), but also artificial illumination, technological features on planetary surfaces, artifacts not associated with a planet, stellar pollution and megastructures.

Thus the classic Dyson sphere, a star enclosed by a swarm or even shell of technologies to take maximum advantage of its output, is only one option for SETI research. As Ravi Kopparapu (NASA GSFC) and colleagues point out in an upcoming paper, we can also cross interestingly from biosignature searches to technosignatures by looking at planetary atmospheres.

Biosignature science is the more developed of the two fields, though we’re seeing a lot of activity in technosignature work, the robust nature of which can be seen in the extensive references the Kopparapu team identifies. As applied to atmospheres, a search for technosignatures can involve looking for various forms of pollution that flag industrial activity.

To my knowledge, most work on atmospheric pollution has targeted chlorofluorocarbons (CFCs), a useful choice because there is no biological source here, although our own use of CFCs occurred in a fairly brief window and for a specific purpose (refrigeration). The NASA work targets the much more ubiquitous nitrogen dioxide (NO2), which can be a by-product of an industrial process and in general is produced by any form of combustion.

“In the lower atmosphere (about 10 to 15 kilometers or around 6.2 to 9.3 miles), NO2 from human activities dominate compared to non-human sources. Therefore, observing NO2 on a habitable planet could potentially indicate the presence of an industrialized civilization.”

Adds Giada Arney, a co-author on the paper and a colleague of Kopparapu at GSFC:

“On Earth, about 76 percent of NO2 emissions are due to industrial activity. If we observe NO2 on another planet, we will have to run models to estimate the maximum possible NO2 emissions one could have just from non-industrial sources. If we observe more NO2 than our models suggest is plausible from non-industrial sources, then the rest of the NO2 might be attributed to industrial activity. Yet there is always a possibility of a false positive in the search for life beyond Earth, and future work will be needed to ensure confidence in distinguishing true positives from false positives.”

Image: Artist’s illustration of a technologically advanced exoplanet. The colors are exaggerated to show the industrial pollution, which otherwise is not visible. Credit: NASA/Jay Freidlander.

This is evidently the first time NO2 has been examined in technosignature terms. The scientists deploy a cloud-free 1-dimensional photochemical model that uses the atmospheric temperature profile of today’s Earth to examine possible mixing ratio profiles of nitrogen oxide compounds on a planet orbiting several stellar types, one of them being a G-class star like the Sun, the others being a K6V and two M-dwarfs, one of these being Proxima Centauri. The authors then calculate the observability of these NO2 features, considering observing platforms like the James Webb Space Telescope and the projected Large UV/Optical/IR Surveyor (LUVOIR) instrument.

Usefully, atmospheric NO2 strongly absorbs some wavelengths of visible light, and the authors’ calculations show that an Earth-like planet orbiting a star like the Sun could be studied from as far as 30 light years away and an NO2 signature detected even with a civilization producing the pollutant at roughly the same levels we do today. This would involve observing at visible wavelengths over the course of at least 400 hours, which parallels what the Hubble instrument needed to produce its well-known Deep Field observations.

But adding yet more interest to K-class stars, whose fortunes as future targets for bio- and technosignature observations seem to be rising, is the fact that stars cooler than the Sun should generate a stronger NO2 signal. These stars produce less ultraviolet light that can break down NO2. As to M-dwarfs, we have this:

Further work is needed to explore the detectability of NO2 on Earth-like planets around M-dwarfs in direct imaging observations in the near-IR with ground-based 30 m class telescopes. NO2 concentrations increase on planets around cooler stars due to reduced availability of short-wavelength photons that can photolyze NO2 . Non-detectability at longer observation times could place upper limits on the amount [of] NO2 present on M-dwarf HZ planets like Prox Cen b.

Where work will proceed is in the model used to make these calculations, which will need to be more complex, as the paper acknowledges:

…when we prescribe water-ice and liquid water clouds, there is a moderate decrease in the SNR of the geometric albedo spectrum from LUVOIR-15 m, with present Earth-level NO2 concentration on an Earth-like planet around a Sun-like star at 10 pc. Clouds and aerosols can reduce the detectability and could mimic the NO2 feature, posing a challenge to the unique identification of this signature. This highlights the need for performing these calculations with a 3-D climate model which can simulate variability of the cloud cover and atmospheric dynamics self-consistently.

The authors consider biosignatures and technosignatures to be “two sides of the same coin,” a nod to the fact that we should be able to search for each at the same time with the next generation of observatories. Finding the common ground between biosignature research and SETI seems overdue, for a positive result for either would demonstrate life’s emergence elsewhere in the universe, and that remains question number one.

The paper is Kopparapu et al., “Nitrogen Dioxide Pollution as a Signature of Extraterrestrial Technology,” accepted at the Astrophysical Journal. (Preprint).

How do we know what is alien life?

Is this the first good science article I have ever been exposed to on Mashable?

“Unless there’s a rabbit jumping in front of a rover — and we have to make sure it’s not a robot — it’s going to be difficult,” said Nathalie Cabrol,

But what a technosignature!

I have a old-ish book on Mars life- Malcolm Walter: “The Search for Life on Mars” (pub. 1999). He writes quite extensively on the ALH 84001 meteorite and the controversy over the biosignatures. The best part of this slim volume is the strategy for where to search for life on Mars based on the experience of scientists working on Earth searching for microbial paleolife in the geology, such as stromatolites. It is much more complex than it seems to non-specialists.

Just as with CFCs, I see NO2 as having a narrow window as an indicator of technological civilization. The bulk of terrestrial NO2 is due to internal combustion engines, especially diesel engines. These appeared at the end of the 19th century and are already looking to be phased out in some classes of engines within the next 50 years as it is a noxious gas that has adverse health effects.

In cosmic time, ETI will either be in the stone age or in a stable, advanced technology age. If civilization collapses, it may result in a return to a pre-industrial age. IMO, therefore the window to detect such gas is but a sliver in the lifetime of any civilization. Any NO2 detection will be from natural processes.

It might be worth looking for such gases, although if it is for the purpose of looking for techno-signatures, it seems to be more like looking for your lost keys under a lampost – because that is where the light is, not where you dropped them.

Whether ETI is biological, machine-based, or both, I think looking for structures, especially in space is the best approach. How you detect them will depend on the technology we have available. Whether that technology is remote detection with interstellar probes, we will have the capabilities to achieve those needed technologies within the next 1000 years, assuming our civilization retains the capabilities and desire to do so.

I fully agree with your thoughts here, many countries actively work to phase out diesel engines. And some have set up the ambitious goal by not allowing any but electrical cars to be sold within the coming decade. There’s countries that might reach that goal even without having to legislate on the matter, such as Norway as most sold cars are electric already. While that country have a huge untapped clean power potential, they build windmills instead. Such will not help in rogue nations that are so insane they use fossil fuel to produce electricity – but I digress. Any sensible civ would go down a similar path, meaning that NO2 or any pollutant is unlikely to be a technosignature for any biological civ. It’s harder to tell how a robotic/machine culture would act, if they consider their ancestors to be kept they might create a zoo, while they consider that horrible oxygen atmosphere to be a hindrance – as it make them rust and corrode. And then replace the atmosphere with more sensible gas, then we would not recognize that world as habitable.
This would not mean that we would be unable to detect a civ with remote means, beside the more obvious one of mega projects in space, a planet with high power production / use would be in thermal imbalance. And with higher resolution studies, not necessarily sharp enough to see details – still might be able to spot if a night side is brighter than it’s supposed to be. But it’s definitely a harder task than looking for unusual gas in a planetary atmosphere.

In the latest episode of Event Horizon, in which John Michael Godier interviews Dr. Sara Seager
Aliens are Hard to Find with Prof. Sara Seager
the discussion includes includes planetary atmospheres and CFCs.

I continue to be skeptical that CFCs can be detected at interstellar distances when their < 1 ppb density here can barely be detected from LEO!

I thought we could detect carbon monoxide from car exhaust on an exoplanet, but after looking at the Aliens are Hard to Find with Prof. Sara Seager I realize it is only a trace gas and probably not detectable because there is not enough of it and the signal would be to small. CFC’s could be ambiguous.

I was thinking about the false positive of oxygen and wondering what are the ideal conditions for an FP which is probably a lot of H2O and it’s photolysis? If there is no oxygen, then there won’t be any industrial NO2 or even any Nitrogen cycle without life or no biotic NO2.

I wonder if the environmental havoc created by the humans inhabiting the existence of Silent Running could be detected at interstellar distances:

Lots of chances for alien pollution signatures…

Hat Creek Observatory gets upgrade to comb galaxy for extraterrestrial life

Hat Creek Observatory in eastern Shasta County is getting an upgrade to make its radio telescopes better able to explore deep space.

The purpose is to help astronomers search for signs of extraterrestrial life throughout the universe, starting with our own galaxy.

Making a detailed survey of the Milky Way is the first of many projects SETI Institute scientists plan at the observatory once upgrades are completed, said Wael Farah, the observatory’s resident astronomer. Scientists will divide the sky into a grid and listen for radio waves square by square.

The SETI Institute already owned the 42 radio telescopes at Hat Creek — the Allen Telescope Array — when it took ownership of the observatory from another non-profit (SRI International) in 2020.

When it took over, SETI — short for Search for Extraterrestrial Intelligence — got to work immediately, funding upgrades with a \$1.2 million grant from Qualcomm technology company co-founder Franklin Antonio, Farah said.

“We’re currently upgrading the (telescopes’) feed system,” he said. This will make the telescopes able to sense radio waves over a wider range of frequencies.

Longevity Is The Key Factor In The Search For Technosignatures

Source: astro-ph.IMPosted March 4, 2021 11:41 PM0 Comments

Each row shows the unconditional probability distribution of longevities τ (left) and time of appearance ti (right) and the probability distribution of the same quantities conditioned to detection. In both rows, the unconditional probability distribution for τ is a log-uniform, while ti is uniformly distributed in the upper row (Model 1 in the text) and normally distributed in the lower row (Model 2 in the text).

It is well-known that the chances of success of SETI depend on the longevity of technological civilizations or, more broadly, on the duration of the signs of their existence, or technosignatures.

Here, we re-examine this general tenet in more detail, and we show that its broader implications were not given the proper significance. In particular, an often overlooked aspect is that the duration of a technosignature is in principle almost entirely separable from the age of the civilization that produces it. We propose a classification scheme of technosignatures based on their duration and, using Monte Carlo simulations, we show that, given an initial generic distribution of Galactic technosignatures, only the ones with the longest duration are likely to be detected.

This tells us, among other things, that looking for a large number of short-lived technosignatures is a weaker observational strategy than focusing the search on a few long-lived ones. It also suggests to abandon any anthropocentric bias in approaching the question of extraterrestrial intelligence. We finally give some ideas of possible pathways that can lead to the establishment of long-lived technosignatures.

Amedeo Balbi, Milan M. Ćirković

Comments: Accepted for publication in The Astronomical Journal

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM) Earth and Planetary Astrophysics (astro-ph.EP) Popular Physics (physics.pop-ph)

Cite as: arXiv:2103.02923 [astro-ph.IM] (or arXiv:2103.02923v1 [astro-ph.IM] for this version)

[v1] Thu, 4 Mar 2021 10:08:25 UTC (405 KB)

Ideas For Future NASA Missions Searching For Extraterrestrial Civilizations

Source: INSTITUTO DE ASTROFÍSICA DE CANARIAS (IAC)

Posted March 10, 2021 at 10:59 PM

A researcher at the Instituto de Astrofísica de Canarias (IAC) is the lead author of a study with proposals for “technosignatures” -evidence for the use of technology or industrial activity in other parts of the Universe- for future NASA missions.

The article, published in the specialized journal Acta Astronautica, contains the initial conclusions of a meeting of experts in the search for intelligent extraterrestrial life, sponsored by the space agency to gather advice about this topic.

In the article, several ideas are presented to search for technosignatures that would indicate the existence of extraterrestrial civilizations, from the most humdrum, such as the presence of industrial pollution in the atmosphere or large swarms of satellites, to hypothetical gigantic space engineering work, such as heat shields to fend off climate change, or Dyson spheres for optimum use of the light from the local star.

Some of the proposed searches look very far in space, across our galaxy and even beyond, while others aim at scanning our own solar system in search for probes that might have been sent here in a distant past. In addition, a study is included of a new way of classifying the technosignatures as a function of their “cosmic footprint”, a measure of how conspicuous they are at large distances.

“We have no idea whether intelligence is something very common in the Universe or, on the contrary, whether it is extremely rare”, explains Hector Socas-Navarro, an IAC researcher, the Director of the Museum of Science and the Cosmos, of Museums of Tenerife, and the first author of the article. “For that reason we cannot know whether these searches have any chance of success. There is no choice but to search and see what we find, because the implications would be tremendous”.

“The idea of searching for technosignatures draws upon the technology we have on Earth today and possible extensions of our technology into the future”, notes Jacob Haqq-Misra, a coauthor of the article and chairman of the TechnoClimes 2020 organizing committee. “This does not necessarily mean that any extraterrestrial technology must be like our own, but imagining plausible extensions of our own future is one place to begin thinking of astronomical searches we could actually do to look for possible technosignatures”.

The search for technosignatures

In 1993, NASA abruptly terminated its initial SETI programme for the search for intelligent extraterrestrial life, when it had hardly started. It comprised two complementary ambitious projects, one using the giant radio telescope at Arecibo, Puerto Rico, and the other with the antennas of the Deep Space Network in California. Now, nearly 30 years later, things have changed and the Agency wants to re-start its search effort.

In the past decade great advances in astronomical instrumentation have been made, leading to a revolution in the science of discovery and study of exoplanets. The new telescopes, and projects on future space missions will for the first time allow the search for so-called biomarkers, evidence for life on other planets. Many experts consider it plausible that in the coming years we will discover extraterrestrial life, even though it is most likely to be life in very simple form.

Given present and future technological advance there will be new opportunities to search for technosignatures. That is why NASA has decided to get involved again in the search for extraterrestrial intelligence, taking advantage of the possibilities of the current and proposed future space observatories.

These subjects, among others, were on the agenda of the meeting TechnoClimes 2020 under the auspices of NASA at the Blue Marble Space Institute of Science (Seattle, USA). With scientists from all over the world, its aim was to propose new developments making way for future advances.

Finally, due to the COVID-19 pandemic, the meeting was held virtually via videoconference, in which 53 researchers from various disciplines coming from 13 countries discussed a range of aspects of the search for other intelligent species.

Article: Héctor Socas-Navarro, Jacob Haqq-Misra, Jason T. Wright et al. “Concepts for future missions to search for technosignatures”, Acta Astronautica, 2021:

Triggering A Climate Change Dominated “Anthropocene”: Is It Common Among Exocivilizations?

Posted March 11, 2021 11:09 PM

We seek to model the coupled evolution of a planet and a civilization through the era when energy harvesting by the civilization drives the planet into new and adverse climate states.

In this way we ask if triggering “anthropocenes” of the kind humanity is experiencing now might be a generic feature of planet-civilization evolution. In this study we focus on the effects of energy harvesting via combustion and vary the planet’s initial atmospheric chemistry and orbital radius. In our model, energy harvesting increases the civilization’s population growth rate while also, eventually, leading to a degradation of the planetary climate state (relative to the civilization’s habitability.)

We also assume the existence of a Complex Life Habitable Zone in which very high levels of CO2 are detrimental to multi-cellular animal life such as those creating technological civilizations. Our models show that the civilization’s growth is truncated by planetary feedback (a “climate dominated anthropocene”) for a significant region of the initial parameter space.

Ethan Savitch, Adam Frank, Jonathan Carroll-Nellenback, Jacob Haqq-Misra, Axel Kleidon, Marina Alberti