Cordial Deconstruction

Observations from our shared single objective reality in a materialistic, naturalistic, & effectively macro-deterministic universe.

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Wormholes, Portals, and Time-Space Travel

Posted by Karl Withakay on February 1, 2013

I’d like to discuss what seems to me to be a fundamental problem with various forms of wormhole/ portal based travel in either space or time as represented in various forms of science fiction.   It occurred to me some time ago, and in fact I started writing this post back in November 2012.  I was reminded of it today while reflecting a little on the last five seasons of Fringe, which led to me thinking about The Observers and the way they can travel through time.

Science fiction frequently treats the Earth as if it was fixed in space relative to all other points and objects in space when we know this is not the case.  Consider, if you will, Back to the Future when the DeLorean hits 88 mph and jumps through time to arrive in the exact same place on Earth, but at a different time.

The Earth rotates on its axis at a speed of about 465 m/s.  In other words, if the Earth was otherwise fixed in space, after standing in place on the surface of the Earth for one second, you’d be about 465 meters from the point in space where you were the previous second.*

However, the Earth is not otherwise fixed in space.  While it rotates about its axis, the Earth orbits the sun at roughly 30 km/s.  So after that one second, you’d be about 30 km from your previous point in space regardless of whether the Earth was rotating on its axis or not.

But wait, there’s more.  The sun and the entire solar system orbit the center of the Milky Way galaxy at around 220 km/s.  This means that after one second, you would have traveled 220 km from the point in space you were at just one second prior, give or take 30 km depending on where the Earth was in its solar orbit and what direction it was traveling relative to the motion of the Solar System.

As the sun orbits the center of the Milky Way, the Milky Way is also not fixed in space.  Our galaxy moves in and with an expanding universe, and is influenced in that motion by various factors, such as the gravitational pulls of the Great Attractor and the Shapley Supercluster.  The Sun and Solar System move with a resultant velocity of about 370 km/s relative to the Cosmic Microwave Background radiation.

So by jumping just one second forwards or backwards in time and arriving in the exact same location in space, you would be several hundred kilometers from the surface of the Earth in space because the Earth, the Solar System, and The Milky Way are all in constant motion in a celestial ballet.

This problem would apply to most wormholes and portals in space (technically space-time) as well unless such portals were gravitationally bound to the locations of the endpoints so that they traveled through space with the planets/ locations of the entry points.  The Stargate franchise gets around this problem nicely by making the wormholes connections generated between two gates rather than two regions of the fabric of space-time itself.

Back to the Delorean- after jumping through time to arrive in the same location in space, it would be stranded in the (near) vacuum of space and the drive doomed to death.  (There’s no way to drive back.)

Interestingly, this brings up another interesting conundrum:  What’s so significant about traveling at 88 mph (or any speed) relative to the surface of the Earth in the first place, and should it matter what direction you are driving relative to the motion(s) of the Earth?  Velocity is relative to some reference frame and not absolute.  The Delorean might be traveling at 88 mph relative to a bystander standing on the ground, but it would be traveling less than that relative to a tailwind and more than that relative to oncoming traffic, to say nothing about its velocity relative to something like the Moon or the Voyager 1 probe.  That DeLorean in free space would be traveling at least 88 mph relative to something; what would or wouldn’t cause it to time travel?  In fact, since there would be no air resistance or friction with the ground, it would likely still be traveling at 88 mph relative to the Earth** as its momentum carried on in space.

I don’t really have a good conclusion or summary here other than to say that traveling in time without also traveling in space may not be such a good idea.  Sorry, Doc.

* Note that the net distance from the previous point will be less that the arc distance traveled, but the difference over the time interval used would be minimal.  I’m also ignoring the motion of the Earth as a result of the Earth-Moon gravitational interactions as they co-orbit each other and other similar factors.

** I suppose things gets even trickier here.  No longer being on the surface of the Earth, the Delorean would no longer be rotating with the Earth’s surface as it revolves about its axis, but would continue on a tangent from where the Earth was before the DeLorean hit 88 mph and jumped through time.  This would be further complicated the change in gravitational forces exerted on the Delorean by the various actors due to their changed locations relative to the Delorean, which will be greater the further it has jumped in time.  There are also other complicating factors involved here, but I think I’ve made my point.

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Posted in Fringe, Sci-Fi, Science, Space, Television, time | Tagged: , , , , | 6 Comments »

Cordial Deconstruction of Neil deGrasse Tyson’s SIUE Talk

Posted by Karl Withakay on December 8, 2011

EDIT 12-12-11  I encourage you to read the comments at the end of this post, including one by Neil deGrasse Tyson himself!  Based on some of the constructive comments and criticisms I’ve gotten here and on Facebook, I’m backing off on the average criticism a bit, but I am leaving it in the post for the purpose of integrity and not pretending like I didn’t say something I did say.

Some of my friends and I went to see Neil deGrasee Tyson speak at SIUE last night (12-7-11).  His talk was very somewhat similar (~25% the same) to his keynote address given at TAM 9 from Outer Space last July, and he made a couple of statements (one of which was repeated from TAM9) that I thought were worthy of a little Cordial Deconstruction.

I know it seems disingenuous to preface a criticism of someone by stating how much you like them, but I’m still going to preface this with the statement that I’m a big fan of Neil deGrasee Tyson, and relish every opportunity to hear him speak, but I did have  problems with a couple of the things he said last night.

An Average Mistake

Dr. Tyson went through a series of slides showing statements made by various people that demonstrate a lack of understanding of science and or mathematics, but his criticism of one of the statements was not very well thought out, in my opinion.  I don’t remember the exact quote, but the essence of the statement was “half of all students are below average”, and Dr. Tyson’s criticism was that this statement was so definitively self obvious as to not require stating.  He said that it was kind of the whole point of average, and that half of any sample would always be below average since average represents the middle.  I know Dr. Tyson understands the concepts of median, mean, and mode, but in spite of that, he apparently didn’t think through his criticism of the statement in that slide.  He made the same point at TAM9, and he apparently hasn’t revised it since then.  It’s just not correct to say that half of any set will always be below average.

Before I can go any further, we have to determine what someone means when they say average.  The most common use of that term is in regards to the arithmetic mean, which is when you add up all the values and divide by the number of values.

I’ll use a simple hypothetical situation with math simple enough to be done without a calculator.  Let’s say I administer a ten question exam to ten students.  Nine students score a perfect 10, and one student scores a perfect 0.

The mean score is 9 ((9*10+0)/10).  In this example using mean for average, 1 student (10%) of the sample scored below average, and 9 students (90%) scored above average.

Sometimes, one might be referring to the median value when they use the term average.

From Wikipedia:

 “Median is described as the numerical value separating the higher half of a sample, a population, or a probability distribution, from the lower half”

By definition would seem to fit Dr. Tyson’s statement.

However, I see two problems here.  Firstly, while it may not be technically incorrect to intend median when referring to the average value, the typical understanding of what is meant by average is the arithmetic mean.  In my opinion, in order to avoid confusion, the use of the word average with general audiences should usually be restricted to refer to the arithmetic mean, and one should say median when they mean median.

The other problem is that even median doesn’t always result in half of a given sample being below average.

Also from Wikipedia:

“At most, half the population have values less than the median, and, at most, half have values greater than the median. If both groups contain less than half the population, then some of the population is exactly equal to the median.”

In the above example, when following the rules used to determine the median value, it comes out to be 10.  Using median for average, 10% of the students are still below average, while 90% are average, and nobody is above average.

There are other things that one could intend when using the term average, such as mode, but these uses would be even more uncommon and really need to be specified when intended.

Initial Mistake

Dr. Tyson also made what in my opinion, was an even grosser misstatement regarding the New Horizons probe to Pluto and the Kuiper Belt.  (To clarify, it was unquestionably a factual misstatement; it is my opinion that the severity of this misstatement is larger than that of his comment about averages.)

He stated that New Horizons was the fastest thing we had ever sent anywhere, and it would eventually overtake the Voyager probes as the most distant man made objects from the Earth.  This is factually incorrect, though there is a grain of truth at the heart of this statement.

While it is true that the New Horizons probe achieved the highest launch velocity of any craft so far, left Earth faster than any other mission or probe, and had the highest initial solar escape trajectory, it neither has the record for highest maximum velocity (the Helios probes hold that distinction), nor is it traveling faster than Voyager 1.  While New Horizons had a higher initial velocity than Voyager 1, Voyager’s velocity was boosted by gravitational slingshots with outer planets to a higher final velocity than New Horizon’s, and New Horizons will never overtake Voyager 1 as the most distant man made object form the Earth (or Sun).

Footnote Acknowledgement of Personal Fallibility

Normally, when I Deconstruct something, I like to be able to review it several times, so I can be sure my Deconstruction is valid, and I am not missing something that would invalidate my criticisms, but the talk last night was live, I can’t review a video of it, and I didn’t take any notes. (Notes would only help me remember things I noticed at the time and would not allow me to look for things that I may have missed anyway.)  As a result, this post was written based on my recall and understanding of what Dr. Tyson said last night (and last July), and is therefore subject to various limitations that could leave me in error in regards to my Deconstruction of the two points discussed in this post.  I therefore acknowledge the possibility that I may have misheard, misunderstood, or improperly recalled the points put forth by Dr. Tyson, and I could be off base on one or both of my criticisms, which is one of the reasons why I allow commenting on my posts, and I invite any relevant commentary anyone might have to add.

Posted in Criticism, Science, Space, TAM | Tagged: , , , , , , , | 10 Comments »

Deconstruction Review of Fringe, Episode 6, Season 3, 6955 kHz

Posted by Karl Withakay on November 11, 2010

A Blue Episode

As always, an episode synopsis can be found over at Scott’s Polite Dissent.

Science Fiction is Often Cooler When Derived From Reality

Number stations are a real phenomenon that I’d heard of before this episode, but I don’t remember where from; maybe I don’t remember because I listened to one.  The stations are pretty much exactly as portrayed in the episode, minus the multiplexed memory wiping signal, and they are reported to have been around since WWI.  They broadcast a series of numbers, words, or letters in a artificially generated voice, tunes or Morse code.  It is generally believed that the transmissions are used to send messages to spies.  It’s a fascinating subject, and is also an excellent basis for a Fringe episode.

Magic Maglev

Broyles describing the floating mystery box:

“It’s not floating, exactly.  Apparently it’s got some sort of magnetics inside.”

OK, but unless the rack also had “magnetics inside”, that doesn’t explain how the box was able to float

Maybe He’s Thinking of Using an iPad?

I don’t know where Peter gets “It’s impossible to do microelectronics with gloves on.” from.  I found links for selling gloves “ideal for use in microelectronics”, links about latex glove allergies in microelectronics applications,  links selling gloveboxes for microelectronics, and a nifty picture of someone wearing gloves while handling a silicon wafer of integrated circuits, and that only took me a few seconds to find.

Analog Demodulation

Considering that Walter didn’t know what about the signal was responsible for the amnesia, he shouldn’t have been so sure that his wa-wa peddle would alter the signal enough to make it safe to listen to.  I would have patched it directly into a computer (without any speaker output), run the audio through a speech to text application to get the numbers, and used an audio program to analyze the waveform to see if there was a multiplexed signal.

Physical Abnormality Almost Always = Evil (In Pop Entertainment)

As soon as I saw the different color eyes, I thought, “There’s no way this guy isn’t evil.”  At Least he didn’t have a humpback.  The real question is, since he turned out to be a shape shifter, did the original person he copied have different colored eyes, and was he therefore also evil?

Bad Planning or Bad Transistor?

So did he not check the device until he got on site, or did the transistor go bad while he was setting the device up?  Rather than having a spare of every individual transistor and integrated circuit that might go bad to do a field repair with, wouldn’t it have made more sense to carry a spare finished, complete board or better yet, a spare device?  By the way, why didn’t he get the spare transistor from the same place he got all the other apparently untraceable parts?  He didn’t buy the transistor after he discovered the bad one; he already had it with him.  Are the writers trying to get me to believe that the only traceable part in either of the two devices was the one replacement transistor?

Wait A Minute…

Uh, how did the bad guy know what frequency the pilot would tune to when trying to re-establish contact with the tower?  (Why was the pilot communicating with the tower over the amateur frequency of 4029kHz before switching to 6880kHz, which is just past the amateur, aeronautical mobile range when neither frequency is used for air traffic control?)

Quotes of the Show: Amusing Dialog

Walter while unpacking another of the devices he can’t figure out:

“Fantastic, now I have bookends.”

Walter to Nina:

“Nina, if I’d have known you were coming, I’d have baked a cake.”

Astrid to Nina:

“He means that…literally.”

For the search Engines

The complete number sequence from the 3rd ring of the calendar was as follows:

8, 21, 16, 7, 11, 8, 10, 13, 12, 34, 17, 9, 15, 8, 42, 40, 27, 11, 9, 21, 18, 12

The 2nd ring had the following text:

Light Meets Dark, Period of Darkness, Dark Meets Light, Period of Light

The Inner ring was numbered 1 through 6, and the outer ring was marked 10- 360 degrees by 10’s.

Walter Is Not an Evolutionary Biologist, and it Shows.

Walter in response to Astrid considering the concept of ancient people who evolved before the dinosaurs absurd:

“Why should we be so arrogant as to assume we’re the first Homo Sapiens who walked the Earth?

Hey, if Walter wants to postulate that we are not the first intelligent species to walk the Earth, fine.  If he wants to postulate that we may not be the first bipedal intelligent species to evolve, fine.  But for Walter to suggest that the species Home Sapiens could have evolved before the first true mammals existed and then later evolved again into the same species displays a total lack of understanding of evolution, common descent, genetics, and the concept of a species.

Neither Verified Nor a Theory

Walter really shouldn’t think that a random work of fiction “verfiies” any of the speculations or conjectures that he liberally calls “theories”.  It correlates with his ideas, and may even support them, but it certainly doesn’t verify anything.

Walter Is Also Not An Astrophysicist or Cosmologist

“The Big Bang and its counterpart, the Big Crunch.  The universe expanding and contracting and expanding.  And endless cycle of creation and destruction.”

This one’s a little more of a nit pick, but Walter’s a little out of date on the Big Crunch.  The expansion of the universe is in fact accelerating and not slowing down, and therefore unlikely to end in a big crunch.

Is Peter an Expert on Eastern European Military Grade Electronics?

What makes a transistor military grade, anyway?  Why would they need to be licensed?  We’re not talking about integrated circuits here.  It’s a simple transistor.  Maybe it’s manufactured to very precise standards, and is very reliable (but not so reliable one didn’t go bad), but what could require it to be licensed?  I suppose it might have been radiation hardened, and maybe the government wants to know who’s using hardened components.  That might make sense since such components might be used in a nuclear weapon.  I still want to know how Peter is such an expert on military grade Polish components.

Tom Cruise’s War of The Worlds Plausibility Problem Resurfaces

How deep are these weapon components buried (seemingly buried for many years) such that nobody has ever accidentally dug one up before, and yet they can be unearthed with conventional construction equipment in an evening?

Posted in Blue Episode, Fringe, Science, Space, Television | Tagged: , , , , | 9 Comments »

Astronomer (Probably) Has 99% Chance of Being Wrong

Posted by Karl Withakay on September 30, 2010

Astronomers have spotted a so-called Goldilocks planet ( Gliese 581g)orbiting another star.  A goldilocks planet is a one that is of the right size to be terrestrial and which lies in the habitable zone of its parent star; conditions which are needed to support life remotely close to as we know it.

During a press briefing, astronomer Steven Vogt, professor of astronomy and astrophysics at the University of California, Santa Cruz said the following:

“Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say, my own personal feeling is that the chances of life on this planet are 100 percent,”

“I have almost no doubt about it.”

This is an astounding statement for any reasonable scientist to make, even one that is an astronomer and not a biologist.  I would even say such a statement borders on irresponsible, assuming there isn’t some missing context or qualification to that statement.  Professor Vogt is essentially saying that the fℓ term (the fraction of the habitable worlds that actually go on to develop life at some point) from the Drake Equation is 100%, which is extraordinarily unlikely to be true.

Whether or not already developed life flourishes everywhere we look on earth is independent from the likelihood of it developing in the first place.   By analogy (admittedly one of the weakest forms of argument), diesel fuel is very hard to light on fire, but burns very well once started.

We really don’t have any reasonable estimate for the fℓ term of the Drake Equation, but I think we can say is significantly less than 100%.  If it were 100%, you would expect life to be spontaneously developing all the time.  You would expect to be able to observe spontaneous abiogenesis at least under laboratory conditions, and yet, we have not yet ever observed life arising from non-life, therefore it must be somewhat less than common.

Additionally, this planet may be the most habitable world we’ve found so far, but the Garden of Eden it ain’t.  First of all, it orbits a red dwarf star, which isn’t ideal.  Red dwarf stars are fairly deficient in UV radiation which is probably important to, and may be vital for, the development and evolution of life.  Also, the planet is tidally locked with its parent star, meaning one side of the planet is always facing the star and one side is always in darkness- not ideal for moderate temperatures on most of the planet.  It’s likely the planet itself would have a Goldilocks zone of its own; the day side is probably too hot, the night side is probably too cold, and the zone bordering the day and night zones is probably the habitable zone of the planet.

Even if my last paragraph regarding the actual habitability of the world in question is totally wrong, even if this planet existed in exactly the same conditions as the Earth in regards to parent star, orbit, composition, magnetic field, etc, there’s just no reason to assume a 100% chance of life.  By definition, that would mean life had to instantaneously spring up the moment habitable conditions were achieved, and that life would continue to spontaneously arise all the time.  I personally believe (without much supporting evidence) that the odds of life developing in any ideal environment are probably very low, but I will confidently say the odds are significantly less than 100%, and they are less for Gliese 581 g than they were and are for Earth.

Posted in Critical Thinking, Criticism, Science, Space | Tagged: , , | 1 Comment »

Reply to a Comment on Interstellar Travel

Posted by Karl Withakay on August 22, 2010

Someone going by the handle of Speising made a comment on my post Follow-Up: Energy Requirements of Interstellar Travel, and the reply I composed grew so large that I decided to make it into a full post.

The comment was:

“So what about ram-jet like ships? probably quite useless (to vulnerable) as carriers for an invasion force, but they do not have the problem of carrying all that fuel with them.
also, of course, If we assume ET doesn’t want to spend 200 or more years making a round trip to Earth… doesn’t necessarily apply for ET’s with, eg., longer life spans than ours.”

Thanks, for the comment, speising.  Basically, you’re talking about a Bussard Ram Jet.  There’s a few problems associated with that.

You’d be scooping up hydrogen to use as a fusion fuel, but hydrogen’s not a particularly good fuel for fusion, believe it or not.  The proton-proton chain, which is the primary source of energy production in stars less than 1.3 solar masses, is a very slow process (like an average of one billion years per reaction in the first step), which is a good thing otherwise the sun would have burned out after just a few million years.

You could theoretically use the CNO cycle for hydrogen fusion, but the confinement and cooling requirements would likely be insurmountable.  We’re talking about temperatures and densities greater than that of the core of the sun.

Also, the interstellar medium isn’t as dense with hydrogen as Bussard thought it was, and you probably wouldn’t be able to scoop up enough fuel.

All this completely ignores the shielding requirements, which I never even went into in my earlier posts, mostly because I concluded interstellar travel was already impractical before even getting to the shielding requirements.  Traveling at speeds even at one tenth the speed of light, every particle of dust floating in space is going to impact your space craft with a lot of kinetic energy.

Let’s assume a particle of cosmic dust floating in interstellar space with zero velocity relative to the Earth.  Let’s also assume this particle is medium sized cosmic dust, say 300 micrometers in diameter, and let’s further assume it’s density is average for cosmic dust, 2.0 g/cm^3.  This particle has a mass of only 2.82X10-8 kg or .028mg.   If our vessel is traveling at 1/10th the speed of light relative to Earth, that particle of cosmic dust is going to impact our spacecraft with a kinetic energy of 12 Megajoules.  To put that into perspective, lets assume a typical automobile mass of 1500kg (3300lb); that particle of dust is going to impact our spacecraft with the same kinetic energy as a car traveling at 454km/h (284mph).  How are you going to protect against that kind of collision, and what do you do if you run into a particle that was 10 or 100 time larger?  300 micrometers is pretty small; a strand of human hair is 100 micrometers wide.

In regards to the other part of your comment,

“If we assume ET doesn’t want to spend 200 or more years making a round trip to Earth… doesn’t necessarily apply for ET’s with, eg., longer life spans than ours.”

I’ll just add that even if an alien species were to have a significantly longer life span that humans, it wouldn’t necessarily follow that their perception of the passage time or their value of time were different than ours.  If science found a way to extend you lifespan to 1000 years, would you be interested in spending 200 years in a submarine without port if there was an alien planet at the end of the trip?  I think 200+  years is still a long time, no matter how many years you have ahead of you in life.

Posted in Critical Thinking, Followup, Science, Skepticism, Space, This Blog | Tagged: , | Leave a Comment »

Deconstruction of the Drake Equation

Posted by Karl Withakay on August 18, 2010

I’ve been scooped by PZ Meyers, but I’m still writing this post anyway.  It fits in well with my recent posts on space;

Cordial Deconstruction of Stephen Hawking? (Am I So Bold?)

Follow-Up: Energy Requirements of Interstellar Travel

Final Follow-Up on the Probability of an Alien Invasion

Where Does Stephen Hawking Think We Can Go?

On Monday  I read this article: Proof of Aliens Could Come Within 25 Years, Scientist Says on Space.com.  The scientist, Seth Shostak, cites the Drake equation when attempting to support his prediction.

The Drake equation, in case you’re not aware, is an equation that is supposed to be used to estimate the number of intelligent civilizations in the Milky Way, and it’s utter garbage.

Form Wikipedia, the equation is:

N = R^{\ast} \times f_p \times n_e \times f_{\ell} \times f_i \times f_c \times L \!

where:

N = the number of civilizations in our galaxy with which communication might be possible;

and

R* = the average rate of star formation per year in our galaxy

fp = the fraction of those stars that have planets

ne = the average number of planets that can potentially support life per star that has planets

fℓ = the fraction of the above that actually go on to develop life at some point

fi = the fraction of the above that actually go on to develop intelligent life

fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space

L = the length of time such civilizations release detectable signals into space.

For the sake of argument, let’s assume the equation itself is basically sound, tough that’s debatable.  In that case, the accuracy of the number we can get from this equation depends on how accurate the values we plug into the individual terms are, so let’s look at  the terms and see how well we can estimate those numbers.

The first term, R*, we have an OK, better than order of magnitude estimate for, so we’re off to not too bad a start, understanding that we’re not looking for a terribly precise value here.

For the second term, fp, we really don’t have a good number for right now.  PZ says we have “growing evidence of values” for this number, and that’s not an inaccurate statement, as long as you understand that the evidence is not quite ripe for picking yet.  While we have been making a lot of progress in detecting extra solar planets,  we’re still only good at detecting larger giant type planets like Jupiter orbiting stars similar to the sun (the Kepler mission may change that).  Because the best way we have to detect planets right now is to detect the wobble the planets induce in their parent star while they orbit, it’s easier to detect planets with a large mass relative to its parent star.  Because of this, we haven’t yet been able to detected any planets of less than several Earth masses, which means what we currently have for this number is really a lower limit for this value, but we really don’t have a good estimate for an upper limit because we don’t know how many stars have only relatively low mass planets and no planets large enough to induce a noticeable wobble.  We’re only on the second term, and we already have a little problem, but as long as we use the lower estimate for this values, we should be OK.

For the third term, ne, we really have nothing but projections using our solar system as a model.  We don’t know how many rocky planets or moons are out there, we don’t know how many of them lie in the habitable zone of their parent stars, we don’t know how many of them have the right elemental composition, we don’t know how many have relatively circular orbits (to avoid extreme temperature variances), etc, etc.  Even if we get better at detecting terrestrial planets, there are so many factors that contribute to the suitability of a planet for supporting life, many of which will be very difficult to detect, that it will be problematic to ever come up with a good value for this number.

As little as we have to go on for the third value, we have basically jack nothing to go on for the all the remaining terms.  We have absolutely no clue about any of those numbers and any attempt to make an estimate for any of them is just wishful thinking or anthropically derived values by people wanting to find an answer.

What fraction of the unknown number of habitable worlds actually develop life?  How does one even make up a number for this and keep a straight face?  Without knowing how life arose here on Earth, how can we begin to  say how probable it is anywhere else?

What fraction of the planets from the previous term develop intelligent life?  Again, who knows?  Our sample of 1 doesn’t give us much to go on.  If the dinosaurs hadn’t died out, would we have intelligent dinosaurs now?  Who knows?  We assume we are the natural, logical conclusion of the evolutionary process because we’re here, but we could be an aberration, an exception to the norm.

What fraction of civilizations develop technology that releases detectable signals?  It might seem reasonable to suggest that if they survive, that this is an inevitable outcome, but we shouldn’t be overly anthropic and assume we are the norm.  We really don’t know.  We do know that when Europeans ventured forth and explored the word, they ran into a lot of pre-industrial and stone age civilizations several millennia behind them technologically.  We can’t even say if the native Americans would have ever developed technology in America under very similar conditions to what the Europeans had let alone say what would be likely on a planets of different conditions and abundances of resources.

How long do such technological civilizations release detectable signals into space?  We haven’t stopped yet, so we don’t even have an anthropic reference number to go on here.

Frankly the best evidence we have for estimating a number for N is the lack of evidence so far.  This is basically the Fermi Paradox.  The Fermi paradox is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations.  I would say that this is not so much a paradox as an indicator that the estimates for N are probably unreasonably exaggerated.  N must be low enough that we’re not currently detecting signals from alien civilizations.  If they’re out there, we can at least say they’re probably not close by or we’d have detected them by now, which means alien civilizations probably aren’t as widely dispersed as the optimists project.

Honestly I’m amazed that anyone tries to invoke the Drake equation, given that we can only reasonably speculate the value for N is between 0 (if you don’t count us) and millions or even billions.  I automatically loose a little respect for any scientist who seriously invokes the Drake equation; the equation is junk science and probably always will be.

Posted in Criticism, Science, Space | Tagged: , , | 1 Comment »

Where Does Stephen Hawking Think We Can Go?

Posted by Karl Withakay on August 11, 2010

Stephen Hawking thinks we need to start looking for another home– not necessarily a replacement, but a summer home, perhaps.  He says our existence is fragile enough that we shouldn’t put all our eggs in one basket and that we need to hedge our bets by spreading humanity to other worlds, just in case something happens here.

I admit that we face all sorts of threats, both from ourselves flirting with disaster and from the universe potentially trying to kill us as well.  Hawking cites climate change, and nuclear or biologic war as man made threats to humanity.  We also face threats we have little power to influence, such as an asteroid impact or a gamma ray burst aimed right at us.

Hawking says “It will be difficult enough to avoid disaster in the next hundred years, let alone the next thousand or million”.  So what are our options, really?  I’ve already covered the relative implausibility and impracticality of interstellar space travel in a previous series of posts (here, here, and here), and we’re not talking about a little exploration scout ship here, we’re talking about an big, massive ark.  It’s arguably questionable whether we would ever have the resources to reseed ourselves on a planet orbiting a distant star if we somehow managed to find one suitable enough to relocate to.  Certainly in the 200 year time frame, we have to think more locally.  We’re talking Mars or one the large moons of the solar system.  Saturn and its moons are a long way out, and the amount of sunlight that reaches Saturn is about 1% of what reaches Earth; that’s not exactly a good setup for a self sustained civilization with no support from the potentially destroyed Earth.  Jupiter is a little closer, but the Jovian system still gets only 4% the solar energy Earth does and 3 of the 4 large moons are bathed in high levels of radiation due to Jupiter’s magnetic field to boot.  As Mercury is too close to the sun, and Venus is pretty much worse than we could hope to make Earth by ourselves, this leaves the Moon or Mars as the most likely candidates.  Mars gets about 44% the solar energy Earth does, and that’s likely enough to use to provide energy and grow crops, plus it has water and a (very) thin atmosphere.  It has no magnetic field to protect against cosmic rays , but we’ve got to work with what we have.

But, how practical is creating a reservoir of humanity on mars or the moon?  We’re not talking about a base or an outpost, we’re talking about a fully self sustained, independent colony here that has to be able to survive on its own.  It has to support a large enough population to provide sufficient genetic diversity to allow our species to survive, at least 1000 people, and it probably needs to be able to grow.  Sure Mars has water and solar energy, and with those two things, you can also have oxygen, but how independently habitable can you make it within 200 years?  How bad would the devastation to the Earth have to be before Mars was more survivable than Earth?  You either have to terraform Mars to make it earthlike enough to support an agrarian civilization , or build an entire self contained infrastructure capable of supporting itself without any support or resources from Earth.  Frankly, if an extinction level asteroid hits the Earth in the next 200 years, my money is on the people who stay behind on Earth; they’ve got a lot more to work with.  A devastated Earth is probably a safer bet than Mars.  If we had the resources and technology to terraform Mars enough to make it habitable independent of technology (technology requires infrastructure over the long term to keep it going), we’d probably be able to neutralize global warming and clean up all the pollution to boot here at home.

Any refuge inside the solar system only works for Earth specific disasters anyway.  Everything in Phil Plait’s Death From the Skies after chapter one would be just as bad for any other location in the Solar System as it would be for the earth, and I’ve previously covered that I don’t consider interstellar travel particularly likely or practical.

If we want humanity to survive really long term, we better hope we do find a way to get humanity to the stars.  Even if we get lucky and dodge all the bullets we and the universe have aimed at us, the sun’s out to get us.  In a billion years, the Earth will definitely be uninhabitable, and nine or so billion years after that, the sun will be a burned out white dwarf providing very little energy to whatever is left orbiting it at that time.  However, even if we manage practical interstellar travel, we’d only be delaying our inevitable doom.  One way or another, there will be an end to the universe as we know it.  Whether it’s a heat death where all stars are burned out and everything in the universe is in thermal equilibrium making work or energy transfer impossible, a big rip, a big crunch, or the decay of ever proton in the universe, eventually there won’t be any place in the universe for humanity to survive.  Sure, we should do what we can to stay alive, but maybe what’s really important is how we live while we are around.  After all, that’s all we really can control.  In the words of Phil Plait at TAM8, “Don’t be a dick.”

EDIT 8-12-10:  Stephen Hawking also has expressed the thought that the possibility that we might be invaded and killed by extraterrestrials is another reason why our existence here on Earth is tenuous, but I’ve already addressed why we shouldn’t worry about being invaded by ET in the posts I cited above. (here, here, and here)

EDIT II 8-12-10:  Apparently I’m not the only one who thinks colonizing other world is prohibitively impracticable.  PZ Meyers has an interesting post this morning where he discusses a post by Charlie Stross that discuses the same idea of how it is  just so absurdly impracticable that it is essentially impossible.

Posted in Criticism, Science, Space, Stephen Hawking | Tagged: , , | 4 Comments »

 
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