Would Centaurians know we exist?

In which we ask the question: If we were denizens of the Alpha Centauri system, and we were looking for extra-terrestrial life from there, using the technology that we have here today, would we be able discover Earth, and/or human life?


To borrow from the brilliant Karl Popper, as long as the existence of extraterrestrial life or intelligence is not falsifiable (meaning you would have to check every exoplanet around every star), you could continue the search for ET forever. I’m not sure that this is in line with the scientific method; ideally you’d be looking objectively at what’s out there and trying to understand what you see from that standpoint.

Radial velocity

Let’s start by pondering our methods for exoplanet detection. One of our most successful is the radial velocity method. It’s not an accident that the first planets we have found this way, are predominantly large planets, in tight orbits around relatively small stars. These simply the easiest planets to find. Unfortunately for the general public, this gives the impression that most planets are very large, in tight orbits around relatively small stars!

On the other hand, our island Earth orbits the sun at 1.0 AU. Its orbit causes the sun to deviate by a mere 0.09 m/s, or 9 centimeters per second. This leads me to wonder what our current best precision is? Only about 1.0 m/s. That’s right, we would need to increase precision by about 100 times in order to detect Earth from Alpha Centauri using the methods we have right now.

Notice that I didn’t say “see” the Earth. That requires a set of optics that we don’t have in orbit yet. Perhaps the James Webb space telescope will come close to that. It will be launched in a few years.

Transit photometry

Using transit photometry, another way of detecting exoplanets, the actual size (rather than just its mass) can be estimated. But for a planet orbiting a Sun-sized star at 1.0 AU, the probability of a random alignment producing a transit is 0.47%. In other words, since the exoplanet has to be lined up just right, the chances of detecting a random planet around any particular star is about one in one hundred (1:100).

Radio emission (SETI)

If an extraterrestrial civilization has a SETI project similar to our own, could they detect signals from Earth?

Many times, we hear that our radio transmissions, which date back many decades, are flying out to outer space at the speed of light. That our broadcasts from 40 years ago are reaching stars that are 40 light-years away. Might xenomorphs be puzzling over TV broadcasts of I Love Lucy or Adolph Hitler’s early radio broadcasts?

That’s partially true. However, there are some problems. Firstly, the vast majority of our radio signals are very weak and are – in effect – aimed at local terrestrial receivers rather than turned up to the stars.

Secondly, the strength of the signal diminishes as the inverse square of the distance. In other words, it would drop off extremely quickly. Even from Alpha Centauri, we would probably not be able to detect radio transmissions from Earth.

Mix that in with these facts: our scientists, possibly frightened by too many viewings of Ridley Scott’s movie Alien, are extremely reluctant to beam radio messages deliberately into space. And surely civilizations on other planets have equally cautious scientists!

Also, when we do think that we have received a signal from outer space, we wait for it to be repeated. This is for scientific verification. But the one signal that we have deliberately beamed into space (the fools!) was NOT repeated. So again, we can imagine alien scientists, possibly detecting one of our signals, and waiting for it to repeat, so they can verify it.

Long story short (or perhaps it’s too late for that) we are not ready to say “yes” or “no” about whether we have alien companions out there in the universe. Baby steps, we are still making baby steps.

Odds are, there are no aliens

Bayesian reasoning nixes chance for life

…the expectation that life — from bacteria to sentient beings — has or will develop on other planets as on Earth might be based more on optimism than scientific evidence.

Bayesian probability is named after 18th century English mathematician and theologian Thomas Bayes. Yes, you can blame him for bursting your bubble.

But here’s the gist of it. In having ONE earth with ONE example of life and evolution on this planet, we have a sample size of exactly ONE. Statistically, that’s horse feathers; you can’t assume anything about the rest of the universe with a sample size that tiny.

Even by throwing around “magical” words like “billions” or “trillions”, meaning galaxies, stars, exoplanets – it still doesn’t guarantee any success in finding extraterrestrial life.

To borrow from Karl Popper, as long as the existence of extraterrestrial life or intelligence is not falsifiable (meaning you would have to check every exoplanet around every star), you could continue the search for ET forever. I’m not sure that this is in line with the scientific method; ideally you’d be looking objectively at what’s out there and trying to understand what you see from that standpoint.

We may just be all alone on our pretty blue marble.



NASA Floats Idea for Titan probe

A Submarine on Titan!

“We propose to develop a conceptual design of a submersible autonomous vehicle (submarine) to explore extraterrestrial seas. Specifically, to send a submarine to Titan’s largest northern sea, Kraken Mare.

This craft will autonomously carry out detailed scientific investigations under the surface of Kraken Mare, providing unprecedented knowledge of an extraterrestrial sea and expanding NASA’s existing capabilities in planetary exploration to include in situ nautical operations.

Sprawling over some 1000 km, with depths estimated at 300 m, Kraken Mare is comparable in size to the Great Lakes and represents an opportunity for an unprecedented planetary exploration mission.

This mission would be a logical follow-on to a Titan surface mission such as TiME (Titan Mare Explorer) or even a component of a flagship mission of multiple vehicles.

The mission concept we propose to study will investigate a full spectrum of oceanographic phenomena: chemical composition of the liquid, surface and subsurface currents, mixing and layering in the “water” column, tides, wind and waves, bathymetry, and bottom features and composition.

Measurements of all these aspects of Titan’s hydrocarbon ocean environment can only be made through focused in situ exploration with a well-instrumented craft.

This investigation represents a significant advancement in our understanding of the history and evolution of organic compounds in the solar system, and hence a critical step along the path to understanding the evolution of life here on Earth and potential life elsewhere in the galaxy.

Titan Submarine, or Titan Sub for short, will be a fully autonomous, highly capable science craft that will allow a complete exploration of what exists beneath the waves on another world.


Slim chance for life on Mars

3065b81600000578-3409278-image-a-16_1453331177007What Antarctica tells us about hope for life on Mars

We tend to assume that every sample of surface soil on planet Earth should be crawling with microbes, but in a corner of Antarctica (University Valley), not only one of the driest and coldest (-9 °F mean year-round) spots on Earth, but also high in elevation, scientists have failed to find life (i.e. microbial activity).

Now this would be a big “whoopie-doo!” from most quarters until you realize that these conditions in University Valley would be considered to be utterly luxurious in any place on Mars.

It was a big surprise for NASA. University Valley was specifically chosen to simulate the conditions around the Mars Rover.

Lyle Whyte, McGill university professor, said that if there is indeed no life here, which is what this study indicates, then the likelihood of finding life on Mars, where conditions are even colder and drier, is slim indeed.

“If we cannot detect activity on Earth, in an environment which is teeming with microorganisms, it will be extremely unlikely and difficult to detect such activity on Mars.”

Reverse-Engineering Aliens on Titan

We’ve been gazing longingly up at Saturn’s moon, Titan, since the Huygens probe touched down, and frankly, for some time before that. Although it’s very dark and cold there, Titan does possess some interesting features that might suggest some kind of alien life forms there: liquid oceans of methane. Also an atmosphere containing hydrogen, acetylene and ethane, each of which appear to be consumed somehow by some as-yet unidentified process,

Our Terran model of life depends on a membrane composed of two layers of lipids. The cell walls in your body are made in such a manner. This membrane was evolved with liquid water, and basically depends on the availability of liquid water in order to main cell function and – live.

Now on Titan, liquid methane is the way to play; water is only available as a solid, and the temperature is very cold. So what sort of cell membrane would have to exist in order for life on Titan to thrive?

I can’t believe somebody has worked this out.

From the research article by , and

“We take a step toward answering this question by proposing a new type of membrane, composed of small organic nitrogen compounds, that is capable of forming and functioning in liquid methane at cryogenic temperatures. Using molecular simulations, we demonstrate that these membranes in cryogenic solvent have an elasticity equal to that of lipid bilayers in water at room temperature. As a proof of concept, we also demonstrate that stable cryogenic membranes could arise from compounds observed in the atmosphere of Saturn’s moon, Titan, known for the existence of seas of liquid methane on its surface.”

Is this what we will be encountering when we finally launch another probe to Titan?

Read the original report: http://advances.sciencemag.org/content/1/1/e1400067

If we ever talk to Alpha Centauri…

There’s a star system near our sun; it’s distance from us is only 4 light years and change. This Alpha Centauri system (AC) has long fascinated science fiction visionaries, since its close distance makes interstellar travel a little easier to imagine.

But consider this: while we are not even close to being able to send a probe to AC at even a fraction of the speed of light, we can, today, send radio messages to this nearby system, with a chance of it being detected within a human lifetime.

Let’s review what kind of system that might be over there. The AC system consists of two stars, both are approximate analogs to our sun. Assuming that it’s possible for planets to have formed around these stars (this would require both stars to have formed at a greater distance apart, then moved closer together), there would then be two habitable zones.

Imagine a habitable planet around each star, or better yet, TWO habitable (and inhabited) planets around Alpha Centauri A, with another around Alpha Centauri B.

Suppose our Venus was not only habitable, but also possibly inhabited. Wouldn’t our space exploration experiences be a little different today? Would our civilization be different? And our attitude toward space exploration?

Inhabitants of one of the planets around Alpha Centauri A would, after exploring and perhaps colonizing, and certainly learning from their Venus, would be prepared to explore Alpha Centauri B’s planet, and possibly then Proxima Centauri.

What I am saying is, that it’s very possible that our nearest star system could be an ideal place to search. The civilization there would not have to be much more advanced than our own, but due to their environment and experiences, they could have a rich set of data for us.

Unfortunately, AC cannot be seen by those of us north of the equator, at about -60 degrees of declination. And more to the point, many scientists are wary about deliberately sending out a message into space, imagining that ET would look like Darth Vader and seek our solar system for reasons that would not benefit humanity.

Keep in mind, however, that faster-than-light travel may be completely impossible, that even a practical sub-light trip to AC would take more resources than any responsible civilization would commit (involving cannibalization of their home star). Further, we may safely presume that any interstellar civilization capable of coming to our star system and wreaking havoc, probably knows about us already.

That said, there is a new radio-telesope array being prepared, south of the equator, that will be capable of detecting radio signals from the AC system. This is the Square-Kilometre Array or SKA (http://www.skatelescope.org/).

The SKA will be capable of detecting extremely weak extraterrestrial signals if existing, and may even detect planets capable of supporting life. Astrobiologists will use the SKA to search for amino acids by identifying spectral lines at specific frequencies. SKA will be able to detect an airport radar within 50 light years.

One of the candidate radiotelescopes in this array is located in Murchison, Australia, close to where the legendary Murchison meteorite was found. Perhaps that is a harbinger for this project’s future success.

Aliens will be here next year, and they will want our beer

Altair is a bright star in the contellation of Aquila. It is only 16.7 light years away. We don’t yet know if there are Earth-sized planets on Altair, but we have just begun to learn how to look.

Nishi-Harima Astronomical Observatory

Here’s the problem: In 1983, Hisashi Hirabayashi and Masaki Morimoto were two astronomers at the Nishi-Harima Astronomical Observatory…

Well, this is awkward. It seems that they had enjoyed a little something to drink.

NOT one of our esteemed scientists…

And they sent out a message in the direction of Altair.

“KANPAI!” Was the message, a traditional Japanese toast. They also sent the details of an alcohol molecule.


This was not the first message that Earthers have sent in the direction of the stars. The famous Arecibo message was sent in 1974, for instance.

But what’s interesting, and a little concerning, is that the signal to Altair will have already arrived by now (ca 1999), and if any Altairians received this message, and if they decided to reply right away, we will receive their message (or their light-speed invasion ships) sometime in 2015.


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