Jumping the Timestream – A Note from 08-09-2012

9 08 2017

Because no one can be certain about one’s own ability to participate in the future, I have a couple of ideas in the works that I’d like to post to the future just in case I (for some reason) don’t get around to it before then. 

First amongst these is this, an idea Chris Hackman and I developed while young astrophysics majors at the Univerisity of Wyoming in early 2000: 

The Antithetic Force

In my view the so-called Hubble Constant is in dire need of a reevaluation in the context of Dark Energy.  I believe the two phenomena are actually the same, and further, that they together represent the evidence of Gravity’s “missing pole” – that is, the push to balance gravity’s pull.  (In other words, “antigravity.”)

I call this force “Antithy,” which as I propose it is a fundamental property of matter – a repulsive force that increases in strength proportionally with distance (i.e., the father away two objects are from one-another, the more strongly they repel).  This is in direct conceptual opposition to Gravity, which is a fundamental property of matter – an attractive force that decreases in strength proportionally with distance (i.e., the closer together two objects are from one-another, the more strongly they attract). 

At first blush, this proposition seems impossible, as soon all objects would be accelerated from one-another beyond the speed of light and the universe quickly undergoes infinite expansion.  However, this conclusion is made without considering the very important spacetime curvature implications of General Relativity.  When looking at the cosmological implications of an Antithetic force from a higher-dimensional context, one quickly realizes that such a force produces an initially-expanding but self-closing universe.  The closure quickly solves Antithy’s own problem, for once closed, the Antithetic Force works in all directions, supplying a sort of repulsive pressure across the universe to counteract initial expansion and shepherd all of the matter in the universe into equilibrium positions with respect to all other matter (like a web of repulsive magnets on the surface of a sphere). 

With this in mind, on small cosmological scales, Gravity dominates.  On large cosmological scales, Antithy dominates.  Thus, Gravity/Antithy is not the weakest but the strongest fundamental force.

I strongly suspect that Antithy is why a consistent value for the Hubble Constant proves perpetually elusive, and Antithy supplies an additional force to explain the nature of “galactic bubbling” in cosmological structure as well as explain the presence of a force attributable to pervasive “dark matter.” 

There you go.  I’m trying as hard as I can to get this proposition into a publication for critical review, but tempus fugit. 

Consider this post a backup for posterity.

Cheers,

Ben McGee

August 9, 2012; 03:00pm

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The “Wow! Reply” – SETI Stunt, Science, or Threat?

22 07 2013

A little less than a year ago, the  National Geographic Channel (NatGeo) executed a truly novel crowdsourcing initiative that I feel is deserving of greater critical attention.

Hailed by some as innovative public engagement, derided by cynics as mere marketing spectacle, and condemned by others as a threat to our very way of life, hindsight suggests that this bold and yet somewhat understated event may have been the most significant contribution of the entire (and much maligned) television project.

The Wow! Reply

Specifically, the initiative’s concept was to solicit tweets from the public, collect and compress them into a digital package, and then “beam” the collective message into space as a potential reply to the famed, so-called “Wow! Signal.”

[The Wow! Signal refers to a 72-second-long radio signal picked up momentarily by SETI’s Big Ear radio telescope in Ohio on August 15, 1977.  As an enigmatic signal that appeared for all the world to represent Search for Extra-Terrestrial Intelligence (SETI) paydirt, it remains to this day arguably the strongest candidate for radio evidence of extraterrestrial life, though that isn’t saying all that much, as the signal has never been rediscovered for confirmation.  As a result, current SETI Institute director of interstellar message composition Douglas Vakoch has claimed that the signal has received more attention than it scientifically merits.  …But that’s a different story.]

In short, NatGeo was keen to supply anyone with access to a computer or smart-phone a chance to say something to the rest of the universe, all in promotion of its newest extraterrestrial-life-themed television show.  There were no restrictions on public participation or the content of anyone’s messages, save the 140-character limit built into Twitter tweets.

In my experience, this so-called “Wow! Reply” was a definite first:  An innovative collaboration between public media and research academia – in this case NatGeo and the famed Arecibo Observatory – that manifested as a public-outreach and active-SETI experiment on a global scale.

The Reply was ultimately successful (in that the interstellar broadcast was successfully performed from Arecibo), and the transmission was targeted back toward the location of the original Wow! signal precisely 35 years to the day from the original signal’s receipt.

An ambitious undertaking for an endeavor entirely conceived and funded to generate interest in a television show, indeed!

However, to understand the varied reactions to the Reply, it’s necessary to first explore how and why the Reply was crafted and executed in the first place.

Arecibo – the largest single-dish telescope in the world.
(Credit: National Astronomy and Ionosphere Center [NAIC]/Cornell U./NSF)

Designing an Interstellar Hook

The idea of the Reply was innovated by Campfire, a consulting firm specializing in “transmedia” storytelling (involving multiple media forms and channels).  The initiative itself was kicked off by soliciting Wow! Reply videos from celebrities and scientists, (to which I contributed).

Some of these videos were over-the-top, while others were serious and science-based.

A personal favorite is Stephen Colbert’s riff on the event.

-In any case, for something as seemingly esoteric as radio SETI, (which is essentially radio astronomy), this was an unprecedented amount of exposure!

Alongside, official word from National Geographic Channel was somewhat divorced from the show it was loosely designed to promote while being surprisingly inspirational and forthright in tone:

“We wanted to come up with some sort of social experiment where we would galvanize people to tap into the curiosity about whether there is life and intelligence elsewhere.”  (Courtney Monroe, NatGeo spokesperson)

“…curiosity around the Wow! Reply is rooted in one of mankind’s oldest unanswered questions: Are we alone in this universe?” (NatGeo Wow! Reply website)

“…[Intelligent extraterrestrial life] would have to decode [the Wow! Reply].  We have carefully structured our encoding and transmission so that it would be difficult to recognize the signal as anything random.  However, decoding the messages … They simply would not have the social context to do that. …no one involved in this project sees it as a truly scientific step toward finding intelligent life in the universe.  After all, this is not a SETI project. … But, that doesn’t mean it’s not a fun exercise, designed to provoke a whole range of questions and conversations down here on Earth – what do we believe is our place in the cosmos?  If we had to sum up the human experience for another civilization, what would we say?” (NatGeo Wow! Reply website)

Ultimately, one could say the Reply served its purpose, as more than 20,000 people tweeted specific messages on the appointed date (June 29, 2012) in order to be included in the transmission, and countless others were made more aware of SETI, radio astronomy, and the existence of the Wow! Signal as a result.

But forgetting the far-fetched and tantalizing possibility of contacting aliens for a moment, what of our own reactions to the Reply?

The Wow! Reaction… from Us.

Prior to the Jun 29 2012 tweet-collection date, there was significant and generally neutral-positive press coverage of the Wow! Reply, which crossed public and professional-level publications, including articles from Slashgear, Huffington Post, and Phys.org.

Unfortunately, however, any fanfare associated with the Reply was quickly siphoned and/or overshadowed by its association with the premier of a television show that, regrettably, communicated a much less scientific or exploratory message.

The press coverage quickly shifted toward neutral-negative, as seen in this NPR article, fading by the time of the transmission of the Reply itself to a simple, short blip on the newswire, exemplified by this NPR piece.

Then, coverage vanished entirely.

Now, a little less than a year later, the collective response from the scientific community and the general public on the Reply has been mixed, running the gamut from enthusiasm to fury.

Why mixed, you might ask?  What could possibly be perceived as negative about something that engaged so many people in the history of science, the wonders of radio astronomy, and possibility of life in the universe?

For the answer, let’s step squarely out of the realm of public media and discuss what NatGeo, wittingly or unwittingly, really engaged in when they conspired to undertake the Reply: METI, or Messaging Extra-Terrestrial Intelligence.

The original 1977 print-out of what, based on the note written on the paper's margin, became known as the "Wow! Signal."

The original 1977 print-out of what, based on the note written on the paper’s margin, became known as the “Wow! Signal.”

Intragalactic Smoke Signals

Sending a message between stars may sound straightforward enough, but actually accomplishing the collection and broadcast of 20,000 tweets into space is a non-trivial technological feat in and of itself.

Addressing the problem of creating something even hypothetically translate-able by a non-terrestrial civilization is an altogether separate and even more daunting task.

Now, it should be mentioned that we – humanity – have been broadcasting signals into space since television broadcasts first began.  Our radio signals travel upwards and out into space in addition to traveling sideways where the antennae on our old TV sets would be best positioned to receive them.

Much like a beacon, these signals travel outward at the speed of light with time, some of which may have reached as far as 80 light years distant from us since then, (a radius that includes upwards of 5,000 stars!).  And crudely, like a smoke signal, the on-and-off of these transmissions has the ability to hypothetically alert another civilization (with the technology to detect them) to our presence on the galactic scene.

File:Arecibo message bw.svg

The 1974 Arecibo Message.

However, with all of this in mind and especially considering that SETI itself is approaching half of a century of maturity as a scientific pursuit, many are surprised to learn that a broadcast with the specific intent of transmitting information to – i.e., communicating with – hypothetical Extra-Terrestrial Intelligence (ETI) has only been attempted eleven times in human history, nine of those being prior to the Wow! Reply.

Think about that.  Eleven times since we developed radio technology.  That’s the galactic equivalent of being trapped in a basement for a year and only calling out for help on the order of (very, very generously) 3 hours.

Not very good odds of being heard at all.

Most notable amongst these earlier transmissions was the Arecibo Message of 1974, a powerful, 210-byte message created by eminent SETI scientist Frank Drake and astronomer Carl Sagan, which was aimed at M13 – a star cluster located a cool 25,000 light-years from Earth.  (Read: It will be 25,000 years before that message reaches its destination! …but a quirk of astrophysics dictates that the stars won’t even be there by the time it gets there.  Everything is moving, after all.)

After that, it is interesting to note that the next message wasn’t even attempted until 25 years later, in 1999 (Cosmic Call 1).  The remaining six broadcasts were conducted in the aughts (2000-2010).

Now, and literally aimed a bit closer to home, we finally arrive at the NatGeo Wow! Reply on August 15, 2012.

The Wow! Reply Transmission

So, how was the Wow! Reply itself transmitted?  Using the Arecibo radio observatory’s formidable 1-megawatt  continuous-wave (CW) S-band transmitter, the project organizers used a 2380 MHz (12.6 cm wavelength) carrier wave to send what promotional materials referred to as a “global tweet” into space.

More specific technical details of the Reply’s assembly, construction, encoding, and transmission have been, somewhat surprisingly, fairly hard to come by.  Even more curiously, I was ultimately able to recover this information in a primary-source context only from an article removed from the National Geographic website not long after it was posted.   (I’m honestly not sure what to make of that.)

In any case, here goes.  Because of uncertainty in the source location of the original Wow! Signal, the Wow! Reply was targeted toward three different stars, which were each selected based on a trio of criteria.  Namely, they were selected based on their location, proximity to our own star system, similarity to our sun, (and I suspect a fair amount of opportunism with respect to the dish’s orientation at the time).

The ultimate winners were/are:

It’s a bit sobering to not just imagine but to know that these stars are not just numbers in a database but are actual stars, whirling about the Milky Way in the precise fashion that our sun does the same, dragging the Earth and the other planets along with it.

And like our Sun, we actually know that at least in one of these cases, these stars are also surrounded by actual alien worlds.  A system of planets not unlike our own.  Astronomers and planetary scientists call them Extrasolar Planets, or Exoplanets.

Comparison of the inner planets of en:55 Cancri and the innermost three planets of the Solar System.  (Credit: Wikipedia user Chaos syndrome)

Comparison of the inner planets of Wow! Reply recipient star system 55 Cancri and the innermost three planets of our Solar System. (Credit: Wikipedia user Chaos syndrome)

Specifically, there are at least five planets orbiting the yellow dwarf star within the 55 Cancri system (see the above image), one of which may skirt that system’s habitable zone. In other words, not only are they available to harbor hypothetical alien life, but one planet in particular (unceremoniously titled) “55 Cnc f” may even be able to support life as we already know it.

A heady endeavor, indeed.  But what is it we actually sent there (to arrive in the year 2053)?

To prepare the message to be delivered to each of these stars, all of the public videos and tweets were first converted to binary data.  Then, scientists at Arecibo were claimed to have added what they refer to as a “training header” to help a hypothetical recipient decode the message, as well as regular repetitions of header sequences prior to each tweet (meaning at least 20,000!) to help distinguish the signal from cosmic noise.

Then, at the power level mentioned above, which is roughly 20 times greater than the most powerful conventional radio transmitter, the enormous surface area of the Arecibo antenna would have boosted the signal to an effective power of more than 10 TeraWatts.

For reference, this is enough power (properly harnessed) such that Doc Brown could have sent Marty McFly back to the future more than 8,000 times.

Pretty powerful, indeed.  But then again, it would have to be.  The nearest star on the recipient list is, in conventional distances, 2,410,000,000,000,000 (nearly two-and-a-half quadrillion) miles away.

And as for how to make the 1 and 0 parts of the radio message, astronomers use what is known as a Binary Phase Shift Keying modulator that literally flops the carrier signal to represent up or down, or 1 and 0.

Now, having sent the Wow! Reply is one thing.  The idea that an extraterrestrial civilization could produce any meaningful information from it is another entirely.

Carl Sagan, one of the first serious proponents and implementers of interstellar messaging.

Carl Sagan, one of the first serious proponents and implementers of interstellar messaging.

Communicating with the Unknown 

The odds of translating an alien message is remote.  Vastly remote.  So remote, in fact, that NatGeo in their own description of the event declares the possibility to be zero:

“[An alien civilization] simply would not have the context to do that.”

So, was this all in vain?  Has the truth of the advertising and marketing aspect of this endeavor finally been laid bare?  Well, not necessarily.  While the broadcast may have been a blast of indecipherable binary code, it may still function as a lighthouse-style beacon, and further, it provides excellent context for explaining the difference between so-called Active SETI and METI here at home.

The Chief Scientist of Russia’s Institute of Radio-engineering and Electronics Alexander Zaitsev has eloquently laid out the argument for the difference between and importance of SETI and METI in his paper, “Messaging to Extra-Terrestrial Intelligence.”

Quite simply, on the one hand the mission of SETI is to produce confirmation of extraterrestrial intelligence.  From this inward-directed vantage, messages such as the Wow! Reply seem to be of little value, as they present a disappointingly remote “shot in the dark,” as it were, of being received, translated, and acted upon.

However, METI proponents possess a much more outward-directed motive, which is to not only ideally communicate with ETI but also to inspire their Wow! Signal moments, even if they are unable to reply.  What a mental back-bend to consider such a possibility!

In Zaitsev’s words,

“METI pursues not a local, but a more global purpose – to overcome the Great Silence in the Universe, bringing to our extraterrestrial neighbors the long-expected annunciation “You are not alone!””

Clever work is being done today on the design of universally-translate-able METI, such has modulating the signal itself to represent physical elements, (e.g., invoking pattens in the radio wave itself so that it serves as the message), yet Zaitsev’s point is that doing so may not even be essential to fulfill a much more significant role to another civilization.

The Hawking Warning

So, that brings us to the next chapter of this interstellar adventure, which is the opposition to METI.  It’s easy to imagine the benefits of such a philosophically-lofty endeavor, e.g., inspiring a “first contact” moment with another civilization that has the capacity to, in turn, broaden our cultural horizons to include a galaxy that has satisfied one of our longest-standing questions – revealing that we are indeed not alone!

However, what of the potential pitfalls?

As it turns out, objections to METI are not new.  In reaction to the famed Arecibo Message of 1974 mentioned earlier, Nobel laureate and astronomer Martin Ryle championed that any attempted extraterrestrial messages be strictly outlawed, at least pending some sort of rigid global review and risk assessment.

Why?

In what may be seen through the lens of future history as either paranoid or prophetic, Ryle’s objections were repeated in 2011 by eminent physicist Dr. Stephen Hawking, who issued an infamous alert warning humanity away from attempting to contact extraterrestrial life.

For someone as engaged in public science outreach as Dr. Hawking has been throughout his career, the proclamation was seen by many as puzzling or counter-intuitive.  However, his concerns were based on hard historical data – something that is obviously difficult to come by when talking about any scenario for which we have no practical example.

In Hawking’s words:

“If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans … We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet.”

Now, there is nothing saying that this must be the case, but the objection certainly merits critical thought.  If relevant, shouldn’t any attempts at interstellar contact be limited as these precautionists warn – at least until we possess a means of planetary defense?

And if the concern is not applicable, why not?  Can we be sure?  (This relates in a way to what I like to refer to as the Andromeda Strain and War of the Worlds spectrum for interplanetary or interstellar lifeform interactions…)

Jamesburg Earth Station, currently transmitting for the Lone Signal project.

Jamesburg Earth Station, currently transmitting for the Lone Signal project.

Domino Effect: The Lone Signal

In perhaps the most intriguing development of all, it appears that the concept of the Wow! Reply earned the attention of an entirely unexpected group – public outreach space scientists themselves.

Just last month, a crowdfunded METI/Active SETI program called Lone Signal began continuous operation at California’s Jamesburg Earth Station.  In a strikingly-similar sort of outreach initiative to the Wow! Reply, the objective of Lone Signal is to continuously transmit “tweet”-sized messages from the public toward Gliese 526, a red dwarf star located a mere 17.6 light years away.

Lone Signal began sending these transmissions on June 17 of this year.  If successful, they hope to activate a network of stations across the Earth, greatly enhancing our star system’s galactic profile, in a manner of speaking.

As for Hawking’s warning about the dangers of exactly such an increase in visibility to the brotherhood of advanced and potentially-threatening alien civilizations that may or may not exist?  Lone Signal’s chief scientist has stated that he believes any nearby advanced extraterrestrial civilizations are already aware of our existence due to radio leakage, and humanity’s previous high-power transmissions could be detected with relatively simple equipment.

While engaging the public in an active outreach program, Lone Signal hopes to resolve what is essentially another civilization’s Wow! Signal problem – since our previous broadcasts have been short bursts that have never repeated, any civilization just tuning in could have caught just a fragment.

Lone Signal aims to broadcast continuously for the foreseeable future, giving other civilizations that which we ourselves have yet to find: the power of confirmation.

The Wisdom of Active SETI and METI

You be the judge.  Was the Wow! Reply the first in a series of media efforts to engage the public in a world that extends beyond our horizons?  Was it simply advertising masquerading as science?  Will it be looked upon as the lure that attracted what may become an unprecedented future conflict over resources with life hailing from another star system?  Or might it hasten the day that we realize we are not alone in the universe, helping us resolve our internal quarrels and participate in a broader spectrum of interactions in our stellar neighborhood already in play?

Time will tell.

But this is the conversation I sincerely wish we would have been in a position to facilitate a year ago.

Comments welcome.





Forecasting the End: The Science of Rogue Planets

21 03 2013

ftefbook2I’m pleased to report that I had the opportunity to consult on (and occasionally appear in) an astronomy/geoscience/climate science crossover project for the Weather Channel this past year, entitled, Forecasting the End.

The show, which premiers this evening, uses extremely-low-probability astronomical or geophysical disasters as a hook to explore and present astronomy, geology, meteorology, and physics concepts in a novel (and admittedly fantastic) way.

Of the six-episode series, the first deals with the concept of so-called “rogue” planets, a timely subject of recent research.

What is a Rogue Planet?

Many astrophysicists, astronomers, and exoplanetologists have set their research sights on puzzling out exactly how it is that new star systems go about forming planets, (in this case “exoplanets,” or planets outside our solar system).  Interestingly, the fruits of their labor have in recent years led to the realization that the process is a frequently violent one.  -So violent, in fact, that during the gravity tango performed between a fledgling solar system’s new planets, one of these “dancers” is thrown right off of the dance floor.

In other words, it seems that planets are often ejected from their home star system in the chaos surrounding a newly-formed star.  This actually serves to help the “dance” between the rest of the worlds calm into a more stable, final set of orbits, perhaps turning it into more of a “march.”

Any one of these escaped exoplanets, then, becomes a “rogue” planet – left to wander the cosmos along its lonely escape trajectory for billions of years.

-And to confirm that this knowledge is more than just theoretical, astronomers revealed last November that they captured what looks for all the world to be a rogue planet in the flesh a mere 75 light-years away:

Infrared image of rogue planet CFBDSIR2149. (Credit: CFHT/P. Delorme)

Infrared image of rogue planet CFBDSIR2149. (Credit: CFHT/P. Delorme)

Rogue Planet as Cosmic Bard

Astronomy-savvy readers may recall a splash last year when researchers reported calculating that there may be billions of these dark, lonely worlds wandering the galaxy.  However, as the “giggle-check” champion astronomer Phil Plait of “Bad Astronomy” fame was quick to point out, compared to the amount of free space in the galaxy, the odds of a collision with these seemingly innumerable rogue planets – any collision – are mind-bendingly slim.

Hence, while the Forecasting’s exercise deals with a disaster that is legitimately statistically possible, it is a threat far less likely than, say, being hit by a meteorite.  Or winning the lottery three times in a row.

Instead, the rogue planet has a different, more sublime function.  It can help us tell a story, and in the telling, learn a little bit more about the Earth.

By exploring the “What if?” scenario provided by the idea of a rogue planet breezing through our solar system, we have the opportunity to illuminate a seemingly-unrelated and often misunderstood phenomena at work much closer to home (and – for the “aha” moment – much more relevant to traditional weather):  Seasons.

Wherefore Art Thou Seasons?

The cosmic roots of our annual swing between months spent shoveling snow and sunning on sandy beaches may not be at all intuitive.  However, this reality becomes much easier to grasp in terms of a cosmic disaster.

Allow me to explain.

Many (intuitively) misunderstand why it is that the seasons exist at all, believing logically that summer is when the Earth is closest to the Sun, and winter is when we’re farthest away.  This is actually not the case.

Why not?  Simply, because the Earth’s orbit is almost perfectly circular, there really isn’t that much difference between the heat received by the Earth at closest and farthest approach to and from the Sun.

Instead, the seasons are caused by the fact that the Earth is tilted as it goes around the Sun.  This means that the Earth doesn’t stand “upright” as it goes round, but rather, it leans:

Illustration that weather seasons are related to the Earth's axis tilt; Summer on the hemisphere pointed toward the sun (northern or southern), and winter for the hemisphere pointed away. (Credit: Ben McGee)

Illustration that weather seasons are related to the Earth’s axis tilt; Summer on the hemisphere (northern or southern) pointed toward the sun, and winter for the hemisphere pointed away. (Credit: Ben McGee)

Consequently, summer is when your side of the Earth (northern or southern hemisphere) is pointed toward the Sun, and winter is when your side of the planet is pointed away.

This is also why, at the equator, the temperature is so consistent throughout the year – at the geographic middle of the planet, straddling the line between hemispheres, you’re neither pointed toward or away during any time of year and experience sunny temperatures year-round.  In contrast, if the “near-and-far” season misconception were true, one would expect snowy winters in Barbados, which simply never occurs…

Playing with Weather via Orbital Dynamics

All of this having been said, the reality explained above – the current cause of our seasons – goes completely out the window in the scenario explored in Forecasting’s rogue planet episode.  There, the orbits of Jupiter and the inner planets are enlongated by a rogue planet flyby (ignoring for the sake of brevity orbital resonances that might make such a shift even more catastrophic than advertised), which has a surprising result:

Such an event turns the previously-mentioned misconception (that seasons are caused by distance with respect to the Sun) into fact for life on Earth!

In such a scenario, the shape of Earth’s orbit becomes more oval (ellipse) than circle, and it travels much closer to and farther away from the Sun during its yearly course (aphelion and perihelion) than it does now.  As a result, seasonal changes due to the Earth’s axial tilt are totally overwhelmed by the global swing in temperatures based just on proximity to the Sun.

NOTE: These effects were actually scientifically modeled on Earth by Penn State astronomer Darren Williams and paleoclimatologist David Pollard in an effort to explore the habitability of worlds with more elliptical orbits around other stars and were published in the International Journal of Astrobiology in 2002.  This paper, which formed the conceptual basis for the effects depicted in this episode, can be found here.

So now, on a post-rogue-planet-soon-to-be-apocalyptic Earth, everyone on the planet experiences summer and winter globally, which leads to a rapid sort of climate change completely disruptive to our way of life:

With an elliptical orbit, (where during half the year the Earth is much closer to the Sun than the other), Earth's seasons are global and driven by proximity to the Sun. (Credit: Ben McGee)

With an elliptical orbit, (where during half the year the Earth is much closer to the Sun than the other), Earth’s seasons are global and driven by proximity to the Sun. (Credit: Ben McGee)

Earthly Take-Home in an Exoplanetary Context

Aside from the tantalizing (for space scientists) or terrifying (for everyone else) infinitesimally-remote specter of some sort of  interaction with a rogue planet, this episode provides a a roundabout and extreme way to drive home a simple truth:  Astronomy relates directly to weather.

The knowledge that the study of the universe beyond can help us understand life at home is a powerful one, and the take-home truth (to me) of the rogue planet episode is that orbit shapes and axis tilts work to define the temperature (weather) for any world orbiting a star.

-And today, because our orbit is not elliptical, it is the tilt of our axis that dominates our climate and causes our seasons.

________________________________________
Stay tuned for more, and I’ll try and have one of these out for each episode!





Surviving Radiation in Space

13 02 2013

Apollo 10 image of Earth taken from 100,000 miles.  [Credit: NASA]

Apollo 10 image of Earth taken from 100,000 miles away.
[Credit: NASA]

For those who are interested in the reality of radiation exposure on Earth, in space, on the Moon, and what this exposure means for our prospects of manned exploration of the Solar System, read on!

The Myths and Truths of Death by Space Radiation

There are persistent groves of misinformation taking root about the lethality of radiation doses for astronauts, particularly for those who are bound for the Moon and/or Near-Earth-Objects, (such as asteroids for research or mining).

Unfortunately, these claims have been given the capacity for widespread proliferation in the fertile cyber-soil of the Internet, and worse, they usually sprout symbiotically with claims that the Moon landings were hoaxed, e.g.:

“We could never have landed on the Moon because the astronauts could never have survived the radiation from cosmic sources/the Van Allen Belts/solar wind.  Therefore, at a sound stage in the Nevada desert…”

Well, since most of these authors capitalize on the preexisting, prevalent fear of radiation to sugar-coat their misinformation pill, most people are unprepared to distinguish technically-compelling pseudoscientific fluff from interpretations of actual data.   So, the below is an effort to arm you, fellow readers, with a guide to help navigate these murky radiation/Moon hoax waters.

NOTE: NASA has produced a factsheet on space radiation as well, which covers the basics of radiation and its effects and measurement.

By reviewing some of this information, you’ll ideally emerge with an enhanced ability to see for yourselves if these radiation-lethality claims hold water.

(SPOILER ALERT: They don’t.)

So, to begin, let’s review what we know about radiation exposure right here on planet Earth.

Current Regulation Levels and Common Radiation Doses

After nearly a half-century of dedicated research, it has been found that there is no detectable increase in the incidence of cancer (the primary threat of penetrating gamma-ray radiation exposure) for people who receive an annual radiation dose of 5,000 millirem (5 rem) or less.

Consequently, the U.S. Nuclear Regulatory Commission’s (NRC) federal regulations currently limit nuclear workers to an annual dose of that amount.  Further, the U.S. Department of Energy’s (DOE) federal regulations, to be on the safe side, currently limit radiological workers’ annual doses to one tenth of the NRC’s limit (500 millirem) unless there is some sort of extreme circumstance or emergency.

But what do these numbers mean?  To help visualize this data, please see the below graph, which places these numbers in simple context with radiation doses we receive naturally from things we all can more easily comprehend, like a chest x-ray:

Current radiation exposure limits and common doses.  [Chart credit: Ben W. McGee]

Current radiation exposure limits and common doses. [Chart credit: Ben W. McGee]

As you can see, there is a certain amount of radiation exposure that we all receive just from standing on planet Earth (see the far right-hand side of the graph).  This natural radiation is unavoidable – cosmic rays can penetrate just about any shield that is not located deep within the Earth, which is itself radioactive and contributing gamma rays from below.  In fact, you will note that the DOE administrative limit mentioned above is actually less than the amount of radiation we all already receive from Earth, plants*, rocks, air, and even ourselves* in a given year.  (*Roughly 1-2% of all potassium on earth is the radioactive isotope, K-40.)

The take-home here is that none of the numbers in the above graph indicate any sort of imminent danger.  In fact, all doses depicted above are evidenced to be “safe” levels, in that they are either natural or below any exposure that the data indicates increases the incidence of cancer in a population (see: ICRP, NCRP).

NOTE:  There are actually two separate dangers that get confused during conversations about the health effects of radiation.  The first kind of danger is for lower-level exposures, which is the danger of increasing your risk of developing cancer later in life.  -This is exactly like the common knowledge that more time spent sunning or tanning during youth equates to an increased risk of skin cancer later on in life.  (It won’t harm you now, but it could harm you later.  It’s a roll of the dice based on your own health, habits, luck, and genetics.) 

The second kind of danger is immediate – the damage and destruction of cells due to a brief, intense exposure to radiation.  Following the sun-tanning analogy, this is akin to a sunburn but spread throughout your body – damage directly caused by the radiation due to its intensity.  While this may also increase your risk of cancer, the threat here is direct injury and your body’s ability to cope.

How do these natural and regulated levels of radiation exposure compare to the radiation dose levels we really know to be definitely unsafe?  For that, see the following expanded graph, which has been color-coded to relate it to the previous one:

Dangerous radiation levels in context.  [Chart credit: Ben W. McGee]

Dangerous radiation levels in context. [Chart credit: Ben W. McGee]

So, as you can see, this graph allows you to immediately identify relationships between ordinary and dangerous radiation exposures to help you understand the concept of radiation exposure and recognize how intense radiation has to be in order to be considered truly dangerous.

  • For instance, you have to be exposed to an intensity of radiation ten million times that of Earth’s normal background levels before worrying about developing radiation sickness.  That’s ten thousand times more powerful than a chest x-ray.
  • You would also need to receive 1,000 chest x-ray scans before worrying about definitely having increased your risk of developing cancer later in life by a single percentage point.

Now, with a little context, we can start to evaluate how bad the space radiation environment really is.

Explorer-1, that discovered the Van Allen Radiation Belts in 1958.  [Credit: NASA/MSFC]

Explorer-1, launched in 1958. [Credit: NASA/MSFC]

Debunking Lethal Radiation from the Van Allen Belts

The United States’ first spacecraft, Explorer-1, detected the presence of so-called “belts” of radiation around the Earth.  These were named after the scientist who designed the instrument that discovered them, Dr. James Van Allen of the University of Iowa.  However, we have learned much since then, including measurements from the radiation instrument RADOM aboard the much more recent Chandrayaan-1 spacecraft (launched in 2008).

Results from RADOM showed that the inner Van Allen belt, which extends from roughly 1,000 miles above the Earth to a little more than 6,000 miles up, appears to be composed of highly energetic particles, such as solar protons, (meaning they pack a higher radiation “kick”).  The outer belt, on the other hand, extends from a little more than 9,000 miles up to a full 33,000 miles up, and it appears to be a little gentler – it is composed primarily of electrons (beta particles).

So, just how bad was the radiation measured there?  Well, it wasn’t something to dismiss (and was academically quite interesting), but it also wasn’t something that would strike fear into the hearts of mission planners:

Peak radiation exposure while traveling through the inner, more powerful belt reached 13,000 millirem per hour, (or 13 rem per hour).  So, if an astronaut were to park in worst part of the inner Van Allen belt for an hour with no shielding, he or she would receive a radiation dose nearly three times the annual “safe” dose for DOE workers and may have bumped up their lifetime risk of a fatal cancer by a percentage point.

Fortunately, however, the time the Apollo astronauts spent traveling through the highest radiation zone of the inner Van Allen belt (at a screaming 11,000+ miles per hr) was fractional – their doses averaged 120 millirem per day.

Go ahead and compare this to the above graphs.

So, it is clear that the Apollo astronauts’ radiation doses in this case were much less than a common CT scan and far less than what a modern astronaut on the International Space Station receives during a 6-month tour (~7,000 millirem).

Hence, simply passing through the Van Allen Belts is anything but lethal.

Astronaut exposed to the raw space radiation environment on Apollo 8.  [Credit: NASA]

Astronaut exposed to the raw space radiation environment on Apollo 8. [Credit: NASA]

Debunking Lethal Radiation Doses from the Earth to the Moon

Like our own sun, all of the other stars in the night sky are nuclear reactors.  Consequently, a constant “rain” of high-energy particles and gamma rays comes at us from the rest of the galaxy, which we call Galactic Cosmic Radiation, or GCR.

Many claim that in “deep space,” e.g., the space between the Earth and the Moon or between Earth and Mars, GCR would prove lethal for a human being.  Yet, the data indicates otherwise.  (Actually, GCR is the primary source of radiation an astronaut normally experiences in all cases, whether in Earth orbit or beyond.)

Let’s have a look.

The data we have about radiation doses during travel from the Earth to the Moon, like with the Van Allen Belts, are not limited to the old Apollo mission data.  For example, the same Chandrayaan-1 spacecraft mentioned above also traveled from the Earth to the Moon and showed a dose during the five day trip (a.k.a. during “translunar injection“) of 1.2 millirem per hour.

Granted, while this is a level nearly a hundred times the average gamma-ray background radiation intensity on Earth, it is still low enough to not present an immediate concern.  Why?  See the above graphs for a comparison – An astronaut would have to spent more than 170 days in this radiation field before even reaching the NRC’s limit for nuclear workers, which equates to no statistical increase in developing cancer.

This sort of radiation exposure becomes an issue when planning long-term missions to the Moon or Mars, which involve several months to years of exposure time, but it certainly bore no immediate threat to Apollo astronauts traveling to-and-from the Moon in a matter of days.

View of the Taurus-Littrow Apollo 17 landing site, 7-19 Dec. 1972.  (Credit: NASA)

View of the Taurus-Littrow Apollo 17 landing site. [Credit: NASA]

Debunking Lethal Radiation on the Moon

Like with the trip from the Earth to the moon, radiation doses on the lunar surface did not even approach immediate danger levels, and while they fluctuated strongly with changes in the Sun’s output, the Moon itself was observed to act as a shield from galactic cosmic radiation.

Consequently, doses received by astronauts on the lunar surface were actually less than that received in lunar orbit, and again, averaged 120 millirem per day.

This value is completely consistent with measurements from the RADOM instrument in 2008 that showed radiation dose rates in lunar orbit of approximately 1-2 millirem per hour.

And again, these are far from doses that would pose an imminent threat to an astronaut’s ability to function.  An astronaut would, quite simply, need to stand in a radiation field of an intensity one hundred thousand times greater for a full hour before suffering the effects of radiation sickness.

The final space radiation threat data in context, plotted in green, can be seen in the following chart:

Space radiation doses in context.  [Chart credit: Ben W. McGee]

Space radiation doses in context. [Chart credit: Ben W. McGee]

Looking Ahead to Planetary Exploration

What does this all mean for the future of manned space exploration?  While all of this does show that claims of radiation lethality in space are plainly false, it also indicates that radiation mitigation will have to be a central planning issue in order for future astronauts to remain within the current bounds of acceptable risk.

Prevailing wisdom accepts that spaceflight and planetary exploration is inherently dangerous and limits what is considered to be acceptable risk to a 3% increase in fatal consequences as a result of radiation exposure – regulations for radiation exposure that are more lenient for astronauts than for other radiation workers.  (Surprisingly, however, this level of risk acceptance is actually more conservative than what is currently accepted for workers in other, much more prosaic terrestrial jobs in many industrial and natural resource fields… but that’s another story.)

There is some research to suggest that chronic, lower-intensity radiation exposure to some of the soft tissues of the eye may lead to secondary negative health effects, such as cataracts, but we’ve only just begun to learn what effects the many alien factors of the space environment have on human physiology, including gravity-induced modifications of bone, muscle, and organ function.  -And again, these effects are not imminently prohibitive and are certainly not immediately lethal.

The Take-Home

Radiation exposure is one of space’s primary threats – but it is not the primary threat.

A lack of atmospheric pressure, the presence of boiling and/or freezing temperature extremes, an intrinsic lack of breathable air and water, and the necessity of shielding against (or avoidance of) micrometeoroids are all arguably more pressing threats.

Radiation at any exposure rate measured in cislunar space certainly wouldn’t prevent an astronaut from visiting the moon, and only if trapped in the most unlikely and unfortunate of orbits would an astronaut ever need be concerned about the possibility of developing a radiation-induced depression of the immune system and – at the extreme – acute radiation sickness.

Take alarmists with a grain of salt and look to the data for the truth.  In fact, it can be seriously argued that conquering our fear of the atom may actually be the means by which the rest of the solar system is opened to humanity.

In my view, that’s where the real conversation is.

_____________________________________________________________

For more information on space radiation doses to astronauts, link (PDF) to the following landmark document, “Space Radiation Organ Doses for Astronauts on Past and Future Missions” by F.A. Cucinotta.





Escape Trajectory Artifacts at WAC-7

7 01 2013

Artist depiction of Pioneer 10. (Credit: Don Davis for NASA)

Just a quick update today on something I’ve been excited to talk about for some time:

I’ve been working during the past year with Dr. Colleen Beck of the Desert Research Institute on long-term planetary science/space archaeology crossover research, the first fruit of which has just hit the cyberverse.

In short, in an upcoming presentation at the Seventh World Archaeology Congress in Jordan on the 18th entitled, “The Bottle as the Message: Solar System Escape Trajectory Artifacts,” Dr. Beck and I are assessing what our escape trajectory spacecraft are really saying about us…  and how the famed Sagan/Drake engraved plaques and records intended as tools for extraterrestrial intelligence under a distant future recovery scenario may actually be serving as a scientific red herring in our own minds when compared to the extraordinary informational value of the spacecraft itself.

More to follow (and a slew of lingering posts on other topics)!





Pluto’s Pain: The Unsung Story of Ceres

20 07 2012

Pluto is once again in the press, astronomers having recently discovered a fifth moon about the tiny, icy world.  -And, again, Pluto’s official designation as a “dwarf planet” is coming under fire.

However, Pluto’s pain really hearkens back to a much older story – one of an unsung planet that stood proudly in the rightful lineup alongside Earth, Venus, Mars, and the rest of the household-name kin of the Solar System for nearly a half-century, yet today nearly no one knows its name:

This is the oft-overlooked story of the scrappy planet Ceres [planet symbol:], which ultimately becomes the story of Pluto.

A Persistent Pattern

The story begins in the late 1700s, when the maturing discipline of astronomy discovered what was believed to be a pattern in the orbital semi-major axes (read: distances between) the planets.  The Cliff’s Notes version of the orbital mechanics here is that there appeared to be a gap between Mars and Jupiter where another planet should have been.

Thus at the turn of the 19th Century began a concerted effort to find this missing world, bringing to bear a contingent of respected astronomers and an arsenal of the most advanced telescopes the science of the time had to offer.

It wasn’t long before they hit paydirt.

(In an ironic turn, I should note that the subsequent discovery was made despite the fact that the ultimate logic of this proposition – the Titius-Bode Law – turned out to be wrong!)

 A Group Effort

In an unbelievable stroke of serendipity, one of the astronomers selected for the search won the race before he’d even entered.  Before Giuseppe Piazzi at the Academy of Palermo, Sicily had even been approached to join the strike team of planet-hunters, he pegged what would turn out to be Ceres while making separate astronomical observations on New Year’s Day, 1801.

A flurry of activity followed during the next year, with the observations changing hands multiple times before a young mathematician named Carl Friedrich Gauss (of differential geometry and magnetism fame), only 24 at the time, predicted the small world’s position to within a half-degree.

Gauss’s calculations led astronomers to the definitive discovery on December 31, 1801, nearly a year to the day of Piazzi’s initial discovery.

The Rise and Fall of Ceres

The discovery of a new world made waves through the astronomical community, with Piazzi naming the planet after the Roman goddess of agriculture, Ceres.  (The names Hera and Demeter have also been bounced about in different cultures, but the current generally-accepted name is Ceres.)

With a diameter of just over 600 miles, (almost exactly the same size of the peninsula of Korea), the world is something of a planetary runt.  However, this did not stop the planet from being included in astronomy textbooks as a brother amongst the rest of the known planets for more than a half-century.  Unlike the asteroids with which it was eventually found to share its orbit, Ceres is a true differentiated astronomical body that has reached so-called hydrostatic equilibrium, becoming a spherical world.

It was only as telescope technology improved and astronomy advanced that the understanding of what Ceres was began to change.  A sudden flood of asteroid discoveries at roughly the same orbital distance began to cast doubt upon Ceres’s uniqueness in the solar system.  Eventually, it was realized that all of these many new, small bodies would either have to also be called planets in order to remain consistent, or the definition of Ceres would have to be changed.

And so, unceremoniously, Ceres was demoted to the ringleader of the asteroids in the latter half of the 19th Century.  This means that by the time our grandparents came on-scene, one would have been hard-pressed to find a modern book that included more than a passing reference to this once-celebrated world.  It had become merely an asteroid.

The 2006 Upheaval

More than a century passed after the discovery of Ceres, and in the 20th Century a familiar story then began to unfold:  Pluto, which was determined to be a tiny world beyond the orbit of Uranus, was discovered in 1930.  It was added to textbooks as the ninth planet, as many of us grew up with.  However, during the 20th and early 21st Centuries, a flood of discoveries of other small, icy bodies in the outer solar system began to cast doubt upon Pluto’s uniqueness.  All of these objects together made up what became known as the Kuiper Belt, a zone of remnant material left over from our star system’s formation and the reservoir from which comets are occasionally pulled.

So, everyone knows that the reclassification of what makes a “planet” resulted in Pluto’s demotion to a new class of worlds called “dwarf planets.”  What few realized, however, was that Pluto’s loss was another’s vindication!

Ceres – waiting patiently in the wings for nearly 150 years – was promoted as a result of the change.  Instead of being “just” an asteroid, it too became a dwarf planet alongside Pluto.  Each as a result of the change evolved into small but noteworthy masters of their respective belts of material – Ceres the dwarf planet of the asteroid belt, Pluto the dwarf planet of the Kuiper belt.

In a way, the controversy resulted in long-awaited justice for little Ceres.

Take-Away

Perhaps, when engaged in your own debate about whether or not Pluto should be called a planet, you might decide to frame the conversation in a larger context.

It really isn’t just about Pluto.  Remember Ceres.





Xenoarchaeology: Reality and Fantasy

3 05 2012

Archaeological evidence of extraterrestrial involvement with ancient human civilizations, as seen in the movie, “Prometheus.” (Credit: Fox)

Cultural Xenoarchaeology

For reasons I can’t immediately explain, (the recent rash of technical publications addressing the concept of “xenoarchaeology” or “non-terrestrial artifacts” nonwithstanding,) there is a tantalizing idea cropping up in a number of recent and upcoming films and television programs.  (See: Indiana Jones and the Kingdom of the Crystal Skull, Prometheus, Ancient Aliens.)

This concept, simply, involves the discovery of archaic evidence of the existence of Extraterrestrial Intelligence (ETI) and/or evidence of physical interactions of ETI in Earth’s (and mankind’s) past.  All of this, arguably, might be lumped under the auspices of the protoscience Xenoarchaeology.

Perhaps this increase in popular consumption of the idea that aliens have been around longer than we have indicates a mounting social awareness of cosmic deep time and the possibility of extraterrestrial life as it is stirred together with our classic, collective existential questions: “Why are we here?” and, “Are we alone in the universe?”

However, these pop-culture expressions and depictions of xenoarchaeology stray pretty far afield of what “scientific xenoarchaeology” would actually look like.

Separating Xenoarchaeology Fiction from Fact

In most part built upon ideas originally popularized by Erich von Daniken decades ago, (and fictionally by H.P. Lovecraft before him,) these modern concepts invoke the assistance of ETI in the development of human civilization as the “gods” of the religions and mythologies of antiquity.  However, this view has long since been shown by archaeologists to be entirely speculative and lacking in any direct, physical supportive evidence, (i.e., it is pseudoarchaeology.)  This stands in contrast to the physical archaeological evidence that does exist to directly support the idea that we humans created civilization, agriculture, the pyramids, etc., without need of assistance.

While the idea of meddlesome, elder-brother or mentor-type ETI is admittedly thrilling, the concept as it relates to xenoarchaeology does not automatically become scientific and in fact differs significantly from the groundwork currently being laid out for scientific xenoarchaeology.

Allow me to provide a few examples of where reality and fantasy diverge:

  • The practice of much fictional xenoarchaeology takes place on Earth, whereas future scientific xenoarchaeologists will likely find their skills of most utility on other worlds during in situ investigations.
  • Fictional/pseudoscientific xenoarchaeology typically centers on terrestrial features of human civilization, (e.g., pyramids, temples, large-scale geoglyphs,) whereas proposed xenoarchaeological investigations will likely center on extraterrestrial features of a possible artificial nature on other worlds.
  • Fictional xenoarchaeology usually assumes the involvement of ETI with a given feature of interest and works from there, whereas scientific xenoarchaeology will be required to rule out all other natural planetary, biological, and geological possibilities before hypothesizing ETI.  (In fact, ruling out features as xenoarchaeological in nature and disproving those making pseuarchaeological claims will probably be the most frequent uses of the existence of a true, scientific practice of xenoarchaeology.)
  • Xenoarchaeologists of popular fiction conduct investigations with their bare hands, whereas scientific xenoarchaeologists will primarily use remote sensing techniques, (satellites, robotic rovers,) to investigate/collect data.  (Or, if they are very lucky, they might one day even conduct work from within a spacesuit or biological quarantine facility.)
  • Fictional xenoarchaeology attempts to find evidence of ETI in terrestrial archaeological sites or artifacts, whereas scientific xenoarchaeology will rely on the fact that ETI was not involved in terrestrial archaeological sites and artifacts in order to construct relationships and methodologies that will be useful in the evaluation of a potential site of completely alien/unknown character. 

I could go on, but hopefully the potential difference between xenoarchaeological reality and fantasy, (like popular depictions of most sciences,) has been made clear.

Why Xenoarchaeology at All?

When considering the concept of scientific xenoarchaeology, invariably the question arises: “Is there a need for xenoarchaeology as a science at all?” 

Admittedly, this question is a good one.  Pseudoscience aside, there are currently no pressing sites of xenoarchaeological interest.  Why, then, expend the effort?

Well, let me first point you to the established field of astrobiology.  This is a field devoted entirely to the origin, evolution, and possibility of extraterrestrial life.  Associated with the field are multiple related academic journals, societies, and even college degree programs. 

Astrobiology is legitimate.  Yet, we have yet to discover even the smallest extraterrestrial microorganism.  Yes – Astrobiology, the scientific study of alien life, is currently conducted in spite of the complete absence of the known existence of alien life.  The field thrives regardless.  Why?

Astrobiology thrives because its underlying assumptions are viewed to be scientifically sound.  Life occurred on Earth, and considering the pantheon of worlds being discovered around other stars, by all modern physical and biochemical reckoning, signs seem to point that it will only be a matter of time until we discover life elsewhere.  (By similar reasoning, the Search for Extraterrestrial Intelligence [SETI] continues its vigilant watch for technological [radio] signs of life in the galaxy, and few nowadays write off the pursuit as being in vain.)

The assumptions underlying the scientific development of xenoarchaeology are, indeed, indentical to those above.  And further, given the ambiguity of the term “intelligence” and modern knowledge of many cosmic threats that can cause mass extinctions, (novas, gamma-ray bursts, asteroid impacts, etc.,) it seems even more likely that material evidence of extinct extraterrestrial life will be encountered prior to the fortuitious discovery of life itself while it is still alive. 

That is, if I were a gambling man, I would wager that xenoarchaeologists get an opportunity to evaluate ultimately definitive evidence of extraterrestrial life prior to astrobiologists.

Xenoarchaeological Relevance

In the final analysis, popular depictions of xenoarchaeology are useful in that they engender a more sophisticated (if not completely sensationalized) view of our place in the cosmos and the possibility of intelligent life in it.  On the technical side, considering the current absence of evidence of extraterrestrial life, xenoarchaeology as a scientific pursuit is equally justifiable to astrobiology and SETI. 

Further, I would argue that like astrobiology, taking the time to rigorously conceptualize a scientific field tangential to those that exist but centered in an extraterrestrial context will help us see ourselves from a clearer scientific vantage; this will invariably serve to enhance our understanding of terrestrial archaeology, anthropology, biology, and yes, even astrobiology.  (Developing an additional means to address some of the planetary pseudoscience out there, e.g., Martian Cydonia, can’t hurt, either.)

And who knows?  Perhaps our space exploration investigations are only a rover or two away from the discovery of that first Martian or Titanean burrow or petroglyph, which history will remember as a moment that literally changes everything. 

My view is that it’d be far better in the event of such a discovery to be proactive and have scientific xenoarchaeology prepared, (in at least a cursory sense,) instead of being reactive and leaving the scientific establishment scrambling to catch up. 

In this sense, perhaps science could stand to learn a thing or two from Hollywood.








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