Transcript: Can You Phone the Past? The Tachyonic Antitelephone

Theoretical physics is an unusual branch of science loaded with interesting thought experiments, concepts and hypothetical devices. You can find everything from cats being simultaneously alive and dead sealed in cardboard boxes awaiting observation to Albert Einstein himself branding quantum entanglement as "spooky" and hard to believe, which it sort of is.

But one of the most odd concepts in theoretical physics stems from Einstein's work. It's the concept of a type of particle called a tachyon, and while still hotly debated, some argue that they could exist.

While science fiction authors have made much use of the word tachyon, the hypothetical particles themselves are not currently part of the standard model of particle physics. We've never seen one, nor any indication that they might exist. It's merely that nature may allow for them to exist, and if they did exist they would exhibit some very strange characteristics.

One would be that they always travel faster than light. But it's worth noting that the speed of light really isn't quite the brick wall that it's made out to be. Popular perception tends to be that the speed of light is a sort of mythical universal speed limit that nothing can ever exceed. But in reality, it only applies to normal matter, and the reason that it does is pretty straightforward.

Whenever you push something that has mass, such as a rocket, it requires that you expend energy to get it going. The faster you go, the more energy you have to expend. This works on a sliding scale and as you approach the speed of light, it requires more and more energy to accelerate further until you reach a point, which is the speed of light, where you would need infinite energy to go any faster. But, you can't ever have infinite energy.

Something that doesn't have mass in the same sense as a rocket, such as a photon of light, propagates through the universe at the speed of light. But relativity doesn't rule out an exact opposite state of affairs, and that brings us back to the tachyons.

If they exist, they would not be able to slow down to the speed of light because that also would require infinite energy. Opposite to normal matter, the less energy a tachyon has, the faster it would travel. Add energy, and it would slow down. But it gets even stranger.

Within relativity, there is an effect called time dilation. This is one of the weirder properties of the universe, but it definitely exists. Space and time are somehow linked, leading to the term space-time. As a result of this, the faster you travel through space, the slower time ticks.

This is really a matter of acceleration. We tend to think of gravity as a pulling force, it drags us down. And it does, but a better way to state it is that gravity is an acceleration towards something. Big, massive objects create acceleration towards them in nearby objects. As such, when you accelerate your rocket in space, time slows down, but it also slows down the closer you get to a gravity source.

So even sitting still here on earth's surface, you are still feeling, as gravity,  an acceleration towards earth's center. This means that time is ticking slower for you than it is for the astronauts on the ISS because they are a bit further away from earth than you are.

While it may seem weird, we know that this is more than just a prediction by Albert Einstein. Time dilation has very real world implications. One of these is on the GPS system. For that system to work you need some serious precision in timing, on the level of nanoseconds.

Trouble is, if clocks here on earth are ticking slower than the clocks on the GPS satellites, then the timing errors would accumulate very rapidly. So, we have to adjust and compensate for time dilation to make the system work, and if we didn't it would take only about two minutes for the GPS system to begin giving false results and it would grow to be increasingly off by about 10 kilometers per day. Any time you use the GPS system, it is actively being adjusted for time dilation.

So, the faster you go the slower time ticks, but another reason that you can't go faster than light is because the speed of light also just happens to be the point at which time quote-unquote "stops". It's a bit more complicated than that really, but we'll leave that for future video. With the tachyons, given that they are traveling faster than light, they would see the same effect in reverse. In short, they would always travel backwards in time.

The existence of tachyons would have broad implications. If they could be used to transmit information, then you could send messages to the past. In 1907 Einstein advanced that faster-than-light communications would create a causality paradox. This is a violation of intuitive cause and effect, where cause does not lead to an effect, but the effect comes before the cause.

If you could communicate faster-than-light then you could call yourself, or telegraph the past as Einstein termed it, and give your past self stock market tips and get rich. This has been termed the tachyonic antitelephone. But that we don't seem to be getting many calls from the future could be telling as to whether all of this is possible, but the debate over it continues.

Now, scientists have looked for tachyons. If they're streaming at us from space, when you look for them they are predicted to look a lot like a cosmic ray, but unlike cosmic rays they would be expected to reach a detector on the ground before the particles produced by their entry in the atmosphere because they would be moving faster. This has not been observed suggesting that tachyons do not exist.

But there is a model that accounts for the absence of tachyons and remains consistent with relativity itself. It comes from the work of James Wheeler and Joseph Spencer, both of Utah State University. Without going too deeply in the abstractness of this model, they re-envisioned space and time as a pair of light cones. One cone is the past, the other is the future connected by the present.

The model is such that while relativity allows for tachyons to exist, the model does not and the possibility for them unequivocally disappears. Only years of debate within theoretical physics will a consensus on this be formed.

But, as often happens in theoretical physics, you end up with a whole other set of questions and oddness. This model also predicts something rather disturbing. It would mean that the universe is deterministic. That kind of a universe is uncertain because the universe appears really probabalistic and even random on the quantum level.

But, some in quantum mechanics have dissented for years about that. They have maintained that the randomness is only an illusion and have kept the idea of determinism alive. Trouble is, a deterministic universe has spooky implications of its own. It would mean that the future is already written and set in stone. In such a case, we would merely be actors following a pre-determined script.

Philosophers still debate what determinism means as far as existence, but another aspect of time dilation and relativity is that not only does time slow down for you as you go faster, relative to the world outside, your space ship is, in fact, time traveling into the future.

That might imply that the future is set in stone and fully deterministic. But in quantum mechanics, determinism continues to fall short. How the two seemingly valid views reconcile is still an unknown, but as Shakespeare once said "All the world's a stage", perhaps he was more right than he thought.

Thanks for listening! I am futurist and science fiction author John Michael Godier currently about to launch a second channel, more on that in the next episode and be sure to check out my books at your favorite online book retailer and subscribe to my channel for regular, in-depth explorations into the interesting, weird and unknown aspects of this amazing universe in which we live. 

Transcript: The End of the Milky Way Galaxy

On this channel, we often think in terms of geologic time rather than time as it is in relation to an average human lifespan. Here, we're more like rocks in our perception of time, or at least I am, thinking ahead billions of years. When trying to think in terms of ten trillion chess moves ahead, there is one, huge white elephant in the room as far as future events are concerned. That's the cosmologically semi-imminent death of the Milky Way Galaxy.

That's not as scary as it seems, a galaxy is really just an arrangement of stars that is subject to change, it doesn't really matter so much to the individual stars of that galaxy. But we often intuitively think of our Milky Way galaxy as something that will permanently spiral its way through the universe unaffected by the lives and deaths of the individual suns that make up its fabric.

But this is not the case, the great familiar barred spiral that is our galaxy has only about four billion years to live. And it's death will be as spectacular as things get, we're set to ram headlong into the great Andromeda galaxy! And there is almost certainly nothing we can do about it no matter how advanced we get in the intervening years.

And, if that's not bad enough, the Andromeda Galaxy is much, much bigger than the Milky Way. Our galaxy contains about 300 billion stars. Andromeda contains a trillion. So the merger will be more like a swallowing up of the Milky Way by Andromeda rather than the other way around.

More, M-31 as it is also known is already so close that you can see it with the naked eye as a greenish-blue smudge in the constellation of Andromeda. That's because it's close, in terms of how huge the universe is, at just 2.5 million light-years away. But, it's getting closer. Fast. As in 68 miles per second fast. The collision speeds involved here are nearly unfathomable.

But don't worry. Space is an unbelievably huge place and the distance between individual stars in galaxies are usually quite huge, barring solar systems with multiple stars already in them. So collisions between individual stars would be very unlikely during the event.

Think of it like this, if you shrink stars and space down to the size of golf balls for comparison, the average distance between stars even in the relatively dense galactic core would still be similar to two golf balls separated by about two miles or a bit over 3 kilometers. That leaves lots of room for stars to pass by each other without colliding. But they will affect each other through gravity.

Within the gravitational chaos, some stars will be ejected from the merging galaxies entirely to wander the darkness of intergalactic space alone until they burn out, but the bulk the two galaxy's stars will coalesce into a new galaxy. While no official name for the resulting galaxy has been adopted, the two current favorites are Milkdromeda and Milkomeda.

But Milkdromeda won't be a beautiful new super spiral galaxy, that structure will be a thing of the past, but rather it will be a generally featureless and ho hum elliptical or with some luck a disc type galaxy maybe with some remnant of spiral structure, a sad end for both galaxies.

But there is one exception to the highly unlikely collision rule. This one is highly likely. Each of the galaxies has at its core a supermassive black hole. In Milkdromeda, these two black holes will approach each other and eventually converge into a single, supermassive black hole. It's unclear what this might do, though possibilities include the creation of a quasar or active galactic nucleus.

So you may be asking yourself what of earth in this melee of impending galactic chaos? A model from 2006 doesn't bode well. As the supermassive black holes coalesce, the sun could get caught up in the gravitational upheaval of it all and is predicted to have a 12 percent chance of getting ejected, though that is subject to change, of course.

But don't worry, getting ejected would take millions of years and have little effect on the solar system. Plus, the increasing luminosity of the sun by that time will have long before boiled the oceans away and the planet will be caught up in a runaway greenhouse effect so bad that the surface may be completely molten awaiting the sun to eventually expand into a red giant and swallow it up.

Well ... unless we're still around and by that time are a galaxy spanning Kardeshev type III civilization with the ability to save earth and prevent the sun's ejection with stellar engines and such. In that case, we will have just gained a trillion new stars to colonize in our great Milkdromedan Empire ... well, unless someone else already has them. In which case, they will command the energy of over three times the amount of stars that we do. Not good.

Transcript: What Lies Between Galaxies? Ejected Stars, Rogue Planets and Exotic Matter

We often view intergalactic space as a no man's land of empty space-time. And, it mostly is, about the most you'll find at most points within it are diffuse hydrogen atoms passing by. But there are some objects wandering the lonely reaches of intergalactic space, including stars and planets. And, it's just possible that there may even be somewhere in this universe an isolated civilization living amongst the black expanses.

One kind of object you might find wandering the space between thegalaxies are ejected stars, often called rogue stars. These are stars that presumably formed inside galaxies and then were ejected out. There are two mechanisms by which this is thought to happen. The first is during the gravitational chaos that occurs when two galaxies collide and the second is when a multiple star system gets too close to a black hole. One member of such a system would get sucked into the black hole, whereas the other or others would be flung out into space. There it becomes something known as a hypervelocity star.

Hypervelocity stars are just that, stars moving at very fast speed, and that can be enough to escape the gravity of their parent galaxy. But what's staggering about rogue stars is how many of them there apparently are. In 2010 and 12 an experiment called the Cosmic Infrared Background Experiment was launched using sounding rockets. The experiment found a strange glow coming from intergalactic space that could not originate from other galaxies.

The best explanation was rogue stars. But the sheer amount of light that was detected suggests that as much as half of all stars in the universe are wandering in intergalactic space. This is interesting because there is a mystery in particle physics called the "missing baryon problem".

Baryons are the particles that make up ordinary matter, a general term for protons, neutrons, etc. Most models of the early universe suggest that there should be way more baryons than there appear to be. But, if half of all stars are wandering intergalactic space, then that could go a long way in helping to account for the missing baryons.

But it likely wouldn't just be stars wandering intergalactic space. They might well take their planets with them ... and any life that might living on those planets. Passing so near a black hole isn't going to be good for life, but if it arises after the ejection then perhaps intergalactic space is teeming with life. Perhaps even civilizations exist out there completely unassociated with galaxies.

There is actually one factor that might favor such life. Most galactic stars reside in high radiation environments hostile to life, such as near a galactic core or in a star cluster. The close proximity to other stars in this case is bad for life, planets near the galactic core would be repeatedly sterilized by close supernovas. But the further you get from the core, out into the spiral arms of the galaxy and beyond, the potential for life grows.

But, there would also be rogue planets traveling without a star in intergalactic space. Similar to stars, these planets would be thrown clear of their parent galaxy through gravitational encounters. We may never see one of these, it would be incredibly hard to spot such a thing in deep space, but they likely exist.

And there are even models where these kinds of worlds can harbor liquid water and life if the planet has a way of keeping warm, such as nuclear decay in the core. This might create an ice shell world, similar to Europa or Enceladus. Or, if you add a thick hydrogen atmosphere, you could have surface liquid water and who knows what else.

One last kind of object that may lie in between the galaxies is very different from stars and planets. It's a hypothetical form of exotic matter that would exhibit negative mass. We're still uncertain whether this kind of matter exists in nature, or for that matter if we could somehow synthesize it. But this form of matter is thought to be possible only in that it's mathematically sound and does not violate the laws of conservation of energy or momentum, but it may violate relativity.

That it could violate relativity in a kind of loophole features prominently when you hear technological theorists talk about creating artificial wormholes, traversing black holes and building alcubierre drives to go faster than light. Most models of these potential future technologies all require this kind of exotic matter to exist.

Whether we can make this stuff is likely not going to be cleared up any time soon. We don't have a complete enough view of gravity, all the current theories fall short and we really need a unified theory of everything essentially. That also happens to be one of the greatest mysteries in modern physics, something even Einstein couldn't figure out. But we need it to answer the questions surrounding negative mass. But, if such a material could exist. What would it be like?

It would be extremely strange indeed. A normal object might weigh 5 kilograms on earth. But an object with negative mass would weigh negative 5 kilograms. Such an object would be expected to be repelled by gravity, in other words it would have the property of anti-gravity, and would fall upwards. Another odd expected effect of exotic negative mass matter is that when you push on it, it would push back. Moving furniture made of this material would be beyond difficult.

If there was some mechanism for this material to somehow have been created in the big bang, which is a huge if, it might well have been repelled by the galaxies completely and potentially lurks in deep space at points between them.

Thanks for listening! I am futurist and science fiction author John Michael Godier and if you would like to help support the channel, check out my Patreon page, link in the description below or check out my books at your favorite online book retailer and subscribe to my channel for regular, in-depth explorations into the interesting, weird and unknown aspects of this amazing universe in which we live. 

Transcript: Ten Ways We May Have Already Detected Alien Life

In celebration of both this channel's one year anniversary and reaching three thousand subscribers, this is a full length documentary made in thanks to the fans of this channel for your support. I am having more fun creating my videos than a person should be allowed to have and the channel has become something that I really love and get excited about.

I never expected it would grow like this when I made my first video nearly one year ago, and it's all thanks to you folks for making it possible. Do look forward to many more years of videos which I will continue to make whenever I come across something cool and unusual in the world of science. So here are ten ways we may have already detected alien life in the universe.

Since the advent of space science, the human race have asked ourselves "are we alone?". In the past, answering this question seemed more straightforward than it is today with Percival Lowell's canals on Mars and pulsars being the signals from little green men. But none of that panned out and the fact is, we still don't know the answer to the biggest question in the universe. But we do know that life itself, at least microbial, seems fairly straightforward, resilient and easily arisen and may have done so on multiple bodies in our solar system alone. It seems likely that we are on the cusp of answering the question, at least far as simple life is concerned.

But what of other civilizations? This too seems to be increasingly moving into the territory of getting answered. If NASA researchers are to be believed, it could happen at any time and probably will within the next 20 years. But, in this search, we must be careful and cautious to prove that whatever we find does indeed indicate the existence of extraterrestrial life. That has not been easy so far.

It's worth noting that in the search for extraterrestrial life there have been many false starts, so it pays to take this entire list with a grain of salt. Two examples of this are HD 164595, a sun-like star with a known planet that appeared to be the origin of a radio signal and it became a major SETI target at the time. But the signal didn't repeat which is SETI's chief criteria, and it turns out, that the signal was within a military communications band. In other words, the origin was very likely a human-launched spy satellite whispering secrets from orbit.

Another example would be the near-earth asteroid 1991 VG. It's a highly unusual asteroid that has a really odd orbit that's a bit hard to explain. It's very similar to Earth's orbit, and that means earth should have long ago flung it out into space or smacked into it. It also has really strange, almost artificial looking reflectivity that makes it change brightness as it rotates to the point that one theory for its origin was that it was a spent rocket stage that someone had forgotten about.

But one other possibility that was floated at the time was that it was an object of alien origin known as a Bracewell or Von Neumann probe, more on those later. But over the years further research has revealed that it's just a strange rock and the alien origin possibility for it is now dead.

This list starts with the least likely candidates and ends with the most likely to have been something of alien origin. I included all life in the criteria, because even a single microbe answers the question. That is not to say that any of the cases will yield the answer to the 'are we alone?' question since some of the options are unlikely to repeat and thus probably won't be available for further study and will remain mysteries forever.

There are also some notable omissions for possible life, for example Europa where we currently have no indication that there could be life there, but the conditions are such that it would be unsurprising if such evidence were found in the near future. Those omissions are for a future dedicated list.

10. Tesla's Signals

This case suffers from being obscured by the mists of time and also a mistaken viewpoint of the period that Mars was almost certainly inhabited by an alien civilization. It clearly is not, the only alien civilization with a presence there is us. There is also a ton of misinformation out there on the internet regarding the originator of this possibility, and many, many urban legends have been spawned from material surrounding Nikola Tesla.

But the underlying claim does technically remain unexplained, though as I understand it and this comes from very old information I heard long ago, it would be extremely difficult to verify today because the frequencies at which it was supposedly visible are so saturated by earth interference that you'd have to put a receiver on the far side of the moon to block everything and check them out.

Nikola Tesla on several occasions claimed that he had received unambiguous alien radio signals from space. But he never gave much in the way of details that we could investigate today. He typically associated them with Mars, which at the time was subject to claims from several mistaken observers to have canals on it. It does not, and as far as radio goes Mars is about as uninteresting of an object as you can get.

Now, I don't doubt that Tesla did in fact receive strange radio signals during his experiments, but those were the very earliest days of radio astronomy done in a time when we had no idea what could emit radio waves. It turned out many things do, including objects in our own Solar System. You can literally grab an old short wave radio and make a loop antenna and listen to Jupiter make repeating ocean-like whooshing sounds that if you didn't know were natural, could be mistaken for something else.

As a result, I think this is a case of smoke without a fire. But since it technically remains unexplained, I put it on the list. Who knows what Mr. Tesla heard.

9. Long Delayed Echoes and Von Neumann Probes

This gets into unexplained radio phenomena that are almost certainly natural in origin. But since we haven't pinned down exactly what causes them, there remains a rather spooky possible alien origin though it is so far beyond unlikely and so highly speculative that I'm barely comfortable including it. But, since it's technically possible, on the list it goes.

In radio there is something called a Long Delayed Echo, or LDE. These occur when a broadcaster sends out a signal and then receives it back after a long period of time has elapsed, often tens of seconds. Now, there are lots of possible scientific explanations for these that included signals getting trapped into a loop going around the earth when the conditions are just right in the upper atmosphere, and signals can bounce off objects in space and return. While we don't yet know for sure, the explanation is most likely natural.

But, the universe is extremely old. Easily old enough for an advanced species in the galaxy to have developed. One possible way for such a species to explore the galaxy is to use self-replicating Von Neumann probes. These are probes that can make copies of themselves like viruses and spread out into the galaxy to explore it. The most famous example of this in science fiction would be Arthur C. Clarke's monoliths from 2001 - A Space odyssey.

With probes of this type, you could theoretically put a probe around every star in the galaxy. That would not take long, it could be done in as little as half a million years, but if your civilization is millions of years old then that's not really a big deal. And the expenditure of resources to do it would be very low, you'd only need to build a few initial probes and send them out to self-replicate. It's actually a scary doable way to explore a galaxy for a sufficiently advanced species, so much so that we're not that far from being able to start this process ourselves.

In fact, this method is seemingly so easy that one of the major arguments against it is that if Von Neumann probes exist, they should literally be everywhere and should have consumed most of the galaxy by now. So much so that any civilization that comes across one might see it as an existential threat and destroy it.

There are arguments for, against and neutral as to the existence of Von Neumann probes and their implications on the Fermi paradox. But it does open up the possibility of such a probe being stationed in our solar system awaiting the proper time to initiate contact and cultural exchange with us. One way such a probe might announce its existence is to repeat radio signals back to the civilization emitting them, sort of like the aliens from Carl Sagan's Contact sending back images of Hitler opening the 1936 Olympics as a sort of initial way to say hello.

Could that be the origin of at least some of the LDE's? It's highly unlikely, but possible. So on the list it goes.

8. Gamma Ray Bursts and Alcubierre Drives

This possibility makes use of a very contentious, hotly debated highly theoretical advanced technology called an Alcubierre warp drive. In a nut shell, the idea is that while matter sitting in normal space cannot travel faster than the speed of light, space itself is not subject to that rule.

So if you can split off and accelerate a piece of space, you can theoretically make it go as fast as you want. If you have a space craft generating a field of sorts to split that piece of space off and send it traveling, it would carry the spacecraft sitting within it along and voila, faster than light travel becomes possible and still remains consistent with relativity because the spacecraft isn't actually moving, the space it's sitting in is.

I will go on record and say that I do not think Alcubierre drives are possible. The subject is fraught with all manner of arguments against it being possible in practice, not the least of which would be truly titanic energy consumption to make it work. But it does have its advocates and the basic core concepts involved are fully scientific, so I include it on the list.

One effect of an Alcubierre drive is thought to be the generation of huge amounts of gamma rays. These should be detectable at long distances. And, we do, in fact, see all manner of strange gamma ray bursts in the universe that are not well understood. One possibility, be it a diminishingly tiny one, is that these bursts are being produced when aliens fire up their warp drives.

7. The Borra/Trottier Signals

In 2012, Ermanno Borra released a paper that suggested that you could detect within the spectra of stars the presence of pulsed laser emissions consistent with the activity of alien races. Along with E. Trottier, Borra then searched through the Sloan Sky Survey for the presence of these signatures.

At the end of last year, Borra and Trottier released a paper that reported that they had indeed identified these kinds of signals in the sky survery. But it wasn't just one or two stars emitting them, it was 234 different stars in the Milky Way. And, the stars that were emitting them were overwhelmingly sun-like, meaning that they had sufficient age and stability for them to have developed advanced alien civilizations.

But stars are strange things and emit all sorts of signals, so natural explanations are always favored. But, to date, no follow up papers have been published regarding this story so it's very much in flux still. But, at the time, scientists were careful to caution that on a scale of one in ten, with ten being the least likely, these signals were a ten. Only time and more study will tell.

6. Fast Radio Bursts

Fast Radio Bursts are a fairly recently discovered phenomenon. While it's overwhelmingly likely that these are of natural origin, one theory suggests that they may not be and are consistent with an alien civilization using a beam to push solar sails and the FRB's are the result of leakage from those beams.

What's noteworthy here is that FRB's do not seem to be consistent with something large, such as a star or galactic core. This is not yet settled, but it seems that they would be more consistent with something originating from a much smaller object, such as a planet.

If so, that would help bolster the solar sail theory.

But where it gets strange is that the solar sail theory makes note of an odd coincidence involving FRB's. If you take the theory from the position of energy and extrapolate what you would need to power the FRB beam, it comes out that you would need a planet about twice the size of earth to have enough room to collect solar energy to create the beam.

On the other hand, if you take the theory from the position of engineering and likewise extrapolate what you'd need to actually build the beam emitter, it ends up that the characteristics of FRB's would be consistent with a water-cooled structure that also happens to be the size of a planet about twice the size of earth.

I stress that FRBs are probably natural in origin, but it's also hard not to scratch your head when coincidences like that start popping up.

5. KIC 8462852

With this case, we enter a new level of possibility because it's the first case where the natural explanations so far advanced have all fallen short and the alien origin theory has still not been discounted.

KIC 8462852 or Boyajian's star is an enigma wrapped within an enigma. The Kepler spacecraft observed the star long term in 2011 and found that within the light curve of that star there were strange dips present as something passed by and blocked the star's light. This in itself would not be unusual, lots of young stars have disc of debris where planets are forming around them that produce light curves just like the one at Boyajian's star.

But the star's motion strongly suggests that this star is not young and should no longer have such a debris disc. That led to the possibility that two planets had crashed into each other in the system creating a new disc. Sounds fair enough. But there are two problems here. The odds that we would just happen to be looking when a very short term event like that happened are, well, astronomical. The second problem, and this discounted that theory, is that such discs absorb light from their star and radiate it back out in the infrared. No infrared radiation was detected at the star consistent with this. Whatever it is, if it's any kind of material, it has to be cold.

But, comets are very cold objects. So the next theory to come up was that a red dwarf, which is there, is passing by Boyajian's star and disrupted its oort cloud sending a hail of cold comets towards the star. Again, this would seem to be a perfectly reasonable explanation, you have the red dwarf as the culprit, we know from our own sun that Oort clouds exist and comets do get disturbed from them and head into the inner parts of solar systems.

But, then this theory fell short when sky surveys taken over the last century showed that the star doesn't just dim short term in dips, but has been dimming overall for a century. This would mean that you'd need a lot of comets in increasing numbers to account for this. The number needed is hard to swallow, on the order of 648,000 comets all orchestrated to pass in front of the star. That renders this explanation possible, but implausible, so other natural explanations are better candidates.

The problem is, every other theory involving a natural origin has some kind of Achilles heel that makes not fit very well. One theory is that the star is dimming and calming down after having recently ate a planet, but once again the chances of catching that just as it was happening are astronomical. It could also be some sort of material passing in the foreground, but we've never seen that sort of thing before and comes with its own set of problems.

So it boils down to this. Whatever we're seeing at Boyajian's star is a really rare phenomenon. If it's natural, whatever it turns out to be will be extremely interesting to science. However, if you have to resort to rare and unusual phenomena to explain something, there's one more possibility that might be consistent with what was being observed to occur at this star.

That would be gigantic alien megastructures. It is the least likely possibility, and has problems of its own. Where is the heat going that it too would radiate? Why is the rate at which it is blocking out starlight increasing? Is it under construction? But if so, how is it being constructed so fast?

The fact is, this mystery remains just as much of a mystery today than when the phenomenon first caught the public's attention. And the alien megastructure possibility still has not been discounted. So while it's very likely a rare natural occurrence causing this, the sticking power of the alien origin theory certainly raises eyebrows.

4. Life in the Clouds of Venus

If someone would have uttered that Venus might harbor microbial life just a decade ago, they'd have been called crazy. Venus seems, at first glance, to be a place unable to host life of any sort due being about as hostile of an environment as you can get on a planet. But in recent years, that's changed and there does indeed appear to theoretically be a way for life to exist in Venus' atmosphere.

The first indicator is Venus's history. Just after the late heavy bombardment about 4 billion years ago, Venus was not as it is today. Presumably, it would have been subject to the same amount of bombardment by comets that Earth and Mars were which would have delivered to it plenty of water. Venus would have been warm enough for that water to exist as a liquid. And while we aren't certain how long it might have had oceans, the estimates very wildly some going so far as to say 2 billion years.

The point is, there might have been plenty of time for microbial life to arise there. In fact, at that time in Earth's history single celled organisms were everywhere and actively oxygenating the atmosphere setting the stage for more than simple life.

But, if microbes did arise on Venus and water did persist for a long period of time, there might also have been enough time for them to adapt while Venus transformed itself into hell planet and become based in Venus's atmosphere in an area where the temperatures are earth-like and comfortable.

Coincidentally, in that same comfortable zone, there is some kind of material absorbing UV radiation. While there are some chemical possibilities to explain this, another possibility would be microbial life using the UV radiation as an energy source.

And, researchers have noted that the presence of sulfuric acid in Venus's atmosphere is not a showstopper for life. There is a way for life to coat itself with polymers known as S8 molecules to withstand the corrosive effects of the acid. As it turns out, S8 molecules have been detected in Venus's atmosphere.

So, it would seem, Venus may have just as good of a chance of having microbes as Mars does. It's certainly worth checking out, which seems to be on Roscosmos' agenda as they plan their next foray to the goddess planet.

3. Martian Meteorites

In 1996 a group of scientists from NASA announced that they had found structures that looked specifically like traces of microbial life in a meteorite known as Allan Hills 84001. It was such a sensation that Bill Clinton went on television and gave a speech about it.

This meteorite bears characteristics that solidly point to Mars as the rock's place of origin. That part isn't debated, it's a rock that was blasted off of Mars in impact. And it's an interesting rock, it appears to have been exposed to water in its past, as would be expected on Mars, and seems to have once been part of a subsurface aquifer. Such places on earth are often just right for life.

The problem with the claim was that these fossils, if indeed that is what they are which is still hotly debated, are significantly smaller than their counterpart microbes on earth, below the generally accepted limit thought possible for microbial life.

That's more than a little odd and gets into a debate about the existence of nanobacteria here on earth and those have been labeled the cold fusion of microbiology. And the debate over whether these structures in this and subsequently other meteorites linked with Mars are indicators of past life has never been settled. But it does remain a possibility, especially in light of the next case.

2. The Viking Biological Experiments

In 1976 NASA landed the first two probes to successfully function on the surface of Mars. Called Viking 1 and 2, they both functioned for years as stationary laboratories on the red planet taking high resolution images and doing soil analyses.

They were both highly successful as missions and greatly increased our knowledge of Mars. But the results of one experiment remain uncertain to this day, for good reason. The experiment tested positive for active microbial life on the surface of Mars.

Part of the problem was that this experiment directly contradicted another. The Labeled Release experiment showed that something was metabolizing nutrients in Martian soil samples. But, the other experiment was intended to determine if there was organic material in the soil, and it indicated that there was not. Metabolism without organics is not what you would expect from life, at least anything similar to Earth's microbes.

Now the labeled release experiment seemed to be a pretty reliable indicator. It was thoroughly tested on earth and never produced a false positive. Compounding this was the fact that both landers had the same experiments and both came up with the same results, despite being 4000 miles apart. It gets even stranger when you account for the fact that when the experiments were altered and done again after the soil was heated, the metabolic activity slowed, just as it would here on earth.

So that led scientists to look to nonbiological possibilities for the metabolism. There are several chemical processes that can mimic metabolism. One of these is formate which can produce a false positive. But it seems likely that Mars wouldn't have a lot of that, and the experiment where it produced a false positive did not have a corresponding sterilized control.

Another possibility is perchlorate, which Mars has been shown to have. The trouble is, perchlorate action does not slow down as you turn the heat up so the Vikings should not have seen a slowdown in metabolism when heat was introduced.

In 2013, a study showed that cosmic rays can make perchlorate break down. This yields hypochlorite the action of which would break down under heat and produce the false positive. But, proponents of the positive result being real, including the original researchers on the Viking missions, point out that hypochlorite hasn't been tested after long term storage of the material, which when doing that on Mars led to a negative result as though any bacteria present in the soil died off when stored. That leaves us without any solid non-biological candidates from which to produce the observed result.

Fast forward again. In 2014 Mars Curiosity detected the presence of organic molecules on the surface Mars. Why didn't the Viking experiments also detect organics if they were present? It turns out that Viking's gas chromatograph-mass spectrometer that was used to look for organics might not have been able to detect them at all and was never designed to look for life in the first place, and that was even stated by the head experimenter at the time in charge of the instrument. The plot thickens.

It has also been shown that the instrument would have required at least a million microbes to detect an organic signature. If there were fewer than that, the instrument would not detect their organics. To complicate things further, perchlorate destroys organic molecules and if it were in the soil, and if it were present at the Viking sites, well there goes the evidence for organics.

The bottom line here is that if these experiments had been performed on earth, where we unequivocally know that there is microbial action, the detection of life in the experiment would have not been questioned. Since they were performed on Mars, the bar is higher and it's difficult to imagine microbial life withstanding the harsh radiation environment of the surface of Mars, but on the other hand we've seen microbes here that can apparently use radiation in their environment to their advantage.

While a majority of scientists have not accepted this result, a vocal minority point out that life is the most likely explanation for the positive result in the Labeled Release experiment in so far as we know.

I don't know what to think either way, but this does qualify as very possibly having been a detection of life on Mars. I won't attach my usual caveat of "highly unlikely" to this one for the simple fact that we're looking to send humans to Mars and if there is any chance of alien microbes living there we need to know about them beforehand. More experiments are needed to answer question this once and for all.

1. The Wow! Signal

Topping the list, perhaps unsurprisingly, is the infamous Wow! Signal. It is perhaps the most unfortunate case, however, in that since it never repeated we are unable to study the nature of it and confirm whether it was really of alien origin. But even though it was detected in 1977, to this day no satisfactory natural or technical explanation for it has panned out and it remains the best candidate we've ever received for an artificial alien signal.

Part of the reason that the signal is so famous is that it bore all of the expected hallmarks of a signal sent by an alien civilization. And contrary to certain claims, the signal did not contain any message. It was just a continuous burst of raw radio energy at the hydrogen line, which is considered the most likely frequency aliens would use to say hello -- one that we on earth intentionally do not broadcast on in deference to SETI.

Now the telescope that detected the signal was stationary and relied on the rotation of the earth to scan the skies. Because of that, it was expected that any signal originating from deep space would be visible to the telescope for just 72 seconds. And the intensity of such a signal would rise for the first 36 seconds and then subsequently fall. Interference from earth would not do this, and both characteristics were present with the Wow! signal.

And, the bandwidth of the Wow! Signal was very narrow, which may further support the notion that it was artificial. Unfortunately, we don't know much else and the discoverer of the Wow! Signal, Jerry Ehman warns that we should not draw vast conclusions from half-vast data, so the origin of the signal is still open for debate. One should always be skeptical of anything that doesn't have confirmation, but out of all the potential signals that the various SETI efforts have detected over the years this is the only one where one could reasonably say "That may well have been it".

Transcript: KIC 8462852 Boyajian's Star Update for 03/03/17

This is an update in my continuing coverage of KIC 8462852 or Boyajian's star for March 3, 2017. For the back story on this fascinating star, see the other videos on my channel starting with my first update of April of last year.

Boyajian's star remains as much of a mystery as it has always been with a host of new natural explanations on the table and the alien megastructure hypothesis remains unlikely, but is still in the mix.

As I reported earlier this year, one theory regarding the type of alien megastructure that theoretically could be involved is stellar lifting, a hypothetical technology that allows a civilization to harvest materials from their star. Along with this theory came a prediction that on February 21st or thereabouts, the next dimming event would occur.

I found this prediction interesting, but highly unlikely due to the alien nature of the theory. That said, it was quite difficult to pin down exactly what happened on the 21st. There was a good reason for this, Boyajian's star was behind the sun at this time and therefore quite difficult to observe on earth and apparently the weather was bad for what ground observation could be done. As a result, there was no data as would normally be available through the American Association of Variable Star Observers who are monitoring this star nightly and plotting what they see in order to catch the next dip.

The star was however under observation by the SWIFT space craft and the main science team investigating the star led by Dr. Boyajian. On a German language news site that I cannot pronounce, link in the description below, members from the team said in an interview that they did not see a dip.

Dr. Heindl notes that SWIFT only observed the star for a few minutes and may not have caught it, but Dr. Boyajian notes that the dips that Kepler observed tended to last for several days so it likely would have caught it. Dr. Heindl's next prediction for a dip consistent with his hypothesis is February of 2019.

And that brings us to a very different kind of prediction, this one from Dr. Boyajian's blog, link also in the description below. There she gives a loose prediction on the next dimming event based on the idea that if you assume that the two large dimming events that Kepler observed are related, then the next dimming event could start in a window of several months before May of this year and several months after. Now, Dr. Boyajian is careful to caution in the post that it's merely a possibility that the two events were related and this prediction may not happen at all.

But if it doesn't happen, it would suggest that whatever is going at the star isn't periodic, at least short term. That might bolster some of the explanations that involve interstellar dust clouds moving past or irregularities with the star itself which one theory suggests that it's in the process of calming down after recently eating a planet.

So there you have it, the predicted February 21st dimming event does not appear to have happened as far as anyone knows and the mystery at Boyajian's star continues. It truly is one strange star and no matter if the explanation is natural, which is far more likely, or alien it's going to be something rare and interesting regardless.

http://www.grenzwissenschaft-aktuell.de/erwartete-verdunklung-von-kic-8462852-blieb-aus20170303/

http://www.wherestheflux.com/single-post/2016/06/09/What-will-happen-in-May-of-2017

Transcript: Life on Pluto?

The search for life on planets within our solar system other than Earth has a long and spotty history. A hundred years ago, the obvious candidate was Mars where some astronomers such as Giovanni Schiaperelli and Percival Lowell were certain they were observing a large network of alien-created canals on the surface of that world. To this day, we have no idea what they were looking at since nothing even close to what they claimed to have observed exists on that planet.

The best guess is that they were seeing optical illusions caused by their own telescopes. We now know that civilization on Mars at any time in its past is an utter impossibility for many reasons, lack of a substantial long-term atmosphere being a good one. High levels of sterilizing solar radiation on the surface due to the lack of a substantial magnetosphere would be another.

But what is possible on Mars is the past existence of microbial life early in its history and a lingering possibility that if you go deep enough into the liquid water aquifers thought to still exist on Mars you may still find holdouts of simple life on the red planet. But what none of the canal-spotting astronomers of old expected was that Mars, just a century later, would no longer be the best candidate for a second source of life in our solar system.

Given that all life on earth requires liquid water to exist, it's a good bet that this is true anywhere else in the universe -- though there are other, theoretical ways for it to happen. And the best sources for liquid water in our solar system, and perhaps the universe at large, may not be big ocean planets like Earth. These are probably somewhat rare. Instead, it's the smaller icy bodies of our solar system that may hold the best chances for developing life.

As we've explored our solar system, we have found no other ocean planets. Mars may have been one long ago, but that ocean is long gone and locked up in ice. Even earth is not so stable in that regard, having gone through numerous great ice ages where the planet's surface came close to freezing over. But we have found, potentially, other alternative oceans on not just one world in the solar system but quite a few including the moons Enceladus, Titan and Europa that could all harbor subsurface liquid oceans that might hold life that in theory could be complex perhaps similar to the life that exists on earth near deep-ocean geothermal vents.

But now we can add one more potential extraterrestrial ocean to that list. And, before the New Horizons flyby, it was probably the most unlikely body to be considered for life in our solar system. It's Pluto, and it would be hard to understate that this tiny world is one bizarre place and the more we study the data returned by the New Horizon's probe, the worse it gets.

There are two remarkable things going on at Pluto. Unknown geologic processes that have led to water ice mountain ranges and what may be complex prebiotic organic chemistry going on in the thin atmosphere of that world. Prebiotic means just that, chemistry that is a precursor to life rather than actually being life. But it's interesting to see at this little world because by all rights it should be completely dead but it's not, it more resembles Titan with its hydrocarbon rain than any other world in our solar system.

Interesting organic chemistry aside, the geologic processes going on at Pluto are not well understood but one possibility is that beneath the surface of the planet exists a liquid water ocean kept warm by radioactive decay in the planet's core. This creates an interesting mix, prebiotic chemistry in the atmosphere and liquid water under the surface existing on the same world opens up a lot of possibilities.

It's going to be a long while before we have a proper understanding of Pluto and it's equally strange and interesting moon Charon, but what is becoming clear is that the most interesting places as far as the potential for life are concerned may be the cold, seemingly frozen worlds far outside the habitability zones of stars. In fact, with the addition of Pluto to the possible list, there are now more worlds that could theoretically harbor life in our solar system outside the sun's habitable zone than within it.