UFOs and skepticism

markus

Active Member
I understand what you mean, but I don't understand how this changes the situation. If two objects have a mutual relative constant velocity with respect to each other, the Lorentz transformation applies.
The Lorentz transformation is a transformation between reference frames, not objects. Sometimes we can be sloppy and say things like "the Earth's reference frame", but it is important to understand that what this means is that we're picking a reference frame where the Earth is at rest. If an object moves at least as fast as light, no reference frame exists where the object is at rest, and trivially there can't be a Lorentz transformation to a non-existing frame.
The carrier for superluminal communication can be a tiny container driven by a hypothetical Alcubierre warp drive. Its velocity relative to the sender would be 7.884.000c. Since it is an object that has a velocity relative to both the sender and the receiver of the message, the Lorentz transformation applies. Alas, this transformation does not yield sensible results for v>c, so we're left in the dark. I do not agree with Markus that "we use v<c throughout".
It is not a matter of agreement -- all Lorentz transformations I used use v < c, which can be readily checked since I was very explicit and showed every step in the argument. You would use a hypothetical v > c Lorentz transformation, should one existed, to describe what happens from the perspective of one of the bubble's occupants -- but that is precisely the regime where the theory is inapplicable because of high spacetime curvature (in Miguel Alcubierre's original formulation, there is no time dilation with respect to Earth for the bubble's occupants, but you'd never know that from special relativity alone). Instead, we use the Lorentz transformation to a different observer, Alice, who's moving subluminally and merely watching the bubble. Relativity says her perspective is valid and she sees the bubble move backwards in time. Either you reject the bubble, or relativity, or causality. It's airtight.

LilWabbit

Senior Member
Relativity says her perspective is valid and she sees the bubble move backwards in time. Either you reject the bubble, or relativity, or causality. It's airtight.

The standard ufologist retort is: "So what if we reject? The history of science is replete with such rejections in the wake of revolutionary theories."

The appropriate response to the retort, imho, is: "Feel free to reject. But like those revolutionary theories you mention, such a rejection should also accept the onus to predict all the observations that were successfully predicted by the rejected theories in order to be deemed a serious scientific exercise. There's no shortcut nor quick fixes in physics to arrive at an alien craft hypothesis just because it's personally appealing."

FatPhil

Senior Member.
Consider the same mechanism on a much smaller scale: Earth.

No, there's no analogue at all.

It's funny, I posted that post in a rush, I was just heading out to the pub, and as I walked there I joked with my g/f that I was sure someone would attempt to say that our (repeated) daily-monthly-yearly expansion across the almost homogeneous and resource-dense globe that we evolved to be specialised for upon was somehow analogous to flinging pods into the emptyness of outer space over multi-million-year timescales. It was a good start to the evening, we all like a laugh.

Mauro

Senior Member
Consider the same mechanism on a much smaller scale: Earth.
I took a lot of time for the first humanoids to arise from evolution but once they started spreading over the Earth's surface, the 'colonization' of Earth by Homo Sapiens went very quickly, measured on an archeological time scale. It wasn't intentional, either. It just happened because of our natural curiosity and search for new resources and new real-estate.

Fermi calculated what a similar scenario would mean on a galactic scale. And he discovered it would take in the order of 10^6 - 10^8 years for an expanding species to 'colonize' the entire galaxy. They do not even have to travel close to light speed, travelling at a fraction of light speed is sufficient. That is why he came up with his famous Fermi paradox: Where are they?
Enclosed is an interesting article discussing galactic colonization scenarios. It contains a table with several studies done earlier:

The authors of the article developed a simulation program and computed some additional scenarios. They all more or less confirm the Fermi paradox: We should be able to detect an expanding alien civilization by now. Maybe we do occasionaly, but we don't want to face it...
Or: maybe we never had any contact with aliens, but we (some of us, at least) do not want to face it...

All the studies you quoted, which try to quantify a galactic expansion rate, start with a big assumption: interstellar travel is possible on the scale needed to create a self-sufficient colony (or a self-replicating 'probe': 'probe' is quite misleading here because it suggests something small, but how something 'small' could be able to self-replicate in space is left to the imagination of the reader)

We have no reasons to think that's true, but we have many reasons to think it's at best very improbable: even interstellar travel in its most basic form (a true 'probe', say 100kg or even less, just meant to dart at a small fraction of light speed near the closest star and relay back some pictures) turns out to be so difficult to have been always relegated to the category of 'dreams' (barring magick, of course).

Then Fermi's paradox gives us some evidence: we have never observed any reliable evidence of alien civilization whatsoever and this is 100% what we would expect in a model where interstellar travel is impossible on the scale needed, while it's not what we would expect from a model where interstellar travel is possible and intelligent life with a technologically advanced civilization is relatively common and long-lived. In order to rescue the possibility of interstellar travel one can start questioning the other assumptions, ie. technologically advanced civilizations are rare (but this does not bode well for aliens) or they are short-lived (but this does not bode well for us too), or invent ad hoc hypothesis which remove the 'badness', rescuing at the same time interstellar travel, aliens, and ourselves. Fantasy is the only limit here: ie. civilizations are indeed short-lived, buy they undergo 'transcendence', whatever that might mean, and become some sort of out-of-this-universe demi-gods. Or aliens are here (and they are many too, and in different forms and since a long time, judging from the 'sightings'), just they have some mysterious reason of their own to always hide in the LIZ giving 'plenty' of 'hints' thay exist while never giving a single piece of solid evidence. This reasoning borders religious beliefs, those being even more improbable because they usually posit both transcendence (afterlife) and a LIZ-living 'alien' deity, while 'just aliens' requires only one of the two hypothesis to be true. One does not need as much faith, but surely needs some.

Itsme

Active Member
Either you reject the bubble, or relativity, or causality. It's airtight.
If you accept that the Alcubierre bubble can only move forward in time in one particular reference frame, causality violations in any other reference frame are prevented. This is explained in the enclosed paper, paragraph 3.1:

Obviously, there can be no paradox if, in one particular reference frame, tachyons can only propagate forward in time.
[footnote:] Of course such a restriction is anathema in the standard approach to special relativity since it picks out a preferred frame. However if you have good physical reasons for picking out a preferred frame (e.g., the rest frame of the Casimir plates) this sort of restriction can make good physical sense.
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Is this rejecting relativity? Perhaps, but there may be good physical reasons for picking out a preferred frame for the Alcubierre bubble.

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• 0107091.pdf
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Itsme

Active Member
Then Fermi's paradox gives us some evidence: we have never observed any reliable evidence of alien civilization whatsoever
According to scientists like Avi Loeb, this is mainly because we have not been seriously searching for this evidence in our own backyard. I agree with him.

they have some mysterious reason of their own to always hide in the LIZ
Not all UFO sightings are in the LIZ. Fravor, for example, observed the tictac from a few thousand feet (this was his closest point of approach) on a bright and sunny day with clear skies. The LIZ is the favorite area for ambiguous sightings, yes, but Hynek did not introduce his categorization of close encounters for nothing:
Sightings more than 150 metres (500 ft) from the witness are classified as "Daylight Discs," "Nocturnal Lights," or "Radar/Visual Reports."
Sightings within about 150 metres (500 ft) are subclassified as various types of "close encounters." Hynek and others argued that a claimed close encounter must occur within about 150 metres (500 ft) to greatly reduce or eliminate the possibility of misidentifying conventional aircraft or other known phenomena.
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Source: https://en.m.wikipedia.org/wiki/Close_encounter

There have been numerous close encounters in UFO history.

Mauro

Senior Member
Mauro said:

Then Fermi's paradox gives us some evidence: we have never observed any reliable evidence of alien civilization whatsoever
According to scientists like Avi Loeb, this is mainly because we have not been seriously searching for this evidence in our own backyard. I agree with him.

Even if that were true, it has no bearing on Fermi's paradox. The model 'interstellar travel is possibile' + 'there are aliens out there' + 'spacefaring civilitazions live long enough' predicts there should be abundant signs of aliens, including numerous colonized worlds and spaceships buzzing around, it should not be difficult to see those signs (unless one adds ad hoc hypothesis). It even predicts we should have been visited and contacted many times, without even the need for 'seriously searching for this evidence' (unless one adds ad hoc hypothesis as above and as discussed before).

Not all UFO sightings are in the LIZ. Fravor, for example, observed the tictac from a few thousand feet (this was his closest point of approach) on a bright and sunny day with clear skies. The LIZ is the favorite area for ambiguous sightings, yes, but Hynek did not introduce his categorization of close encounters for nothing:
Sightings more than 150 metres (500 ft) from the witness are classified as "Daylight Discs," "Nocturnal Lights," or "Radar/Visual Reports."
Sightings within about 150 metres (500 ft) are subclassified as various types of "close encounters." Hynek and others argued that a claimed close encounter must occur within about 150 metres (500 ft) to greatly reduce or eliminate the possibility of misidentifying conventional aircraft or other known phenomena.
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Source: https://en.m.wikipedia.org/wiki/Close_encounter

There have been numerous close encounters in UFO history.

What do you mean by 'Fravor's tic-tac is not in the LIZ'? Are you arguing we have enough information to positively identify it? Then why is it an 'UFO', as you say? The distance from where an observation was taken means nothing, it's the quantity and quality of the data at hand which matter. We can be pretty sure there are planets around stars 100 light-years away because we have good data, yet we cannot say with certainty (say, with 95% confidence) what the tic-tac exactly was because we lack the necessary data, thus it's in the LIZ.

There have been numerous close encounters with ghosts and spirits in human history (many more than with aliens I'd bet), are they out of the LIZ too?

DavidB66

Senior Member
I'd like briefly to revert to the 'thought experiment' I mentioned in my #41 above. An observer A sends an FTL message to observer B, who sends an FTL message acknowledging receipt back to A. I suggested, what I hoped was uncontroversial, that the time at which A sent his message to B would always be earlier than the time at which he received the return message from B, as recorded on A's own clock, static in A's inertial reference system. We could specify the procedure more precisely as follows:

- A's message reads: 'Dear B, I am sending you this message at time T1 as shown on my clock. Regards, A'. The time T1 could be printed automatically in the message, and simultaneously recorded as a mark on a moving tape in A's system, as in a seismograph.

- B's return message reads 'Dear A, I received your message sent at time T1 as shown on your clock, and I am sending this return message at time T2 as shown on my clock. Regards, B.'

- On receiving the return message, A would note the time T3 as shown on his clock, which could also be simultaneously recorded on A's moving tape.

Since A and B may be static in different inertial reference systems, with clocks which may be running at different rates, it is conceivable that T2 is chronologically earlier than T1, (e.g. if T1 reads as '3 p.m.' , T2 might conceivably read as '2 p.m.') But I contend that even if this is the case, T3 is still bound to be later than T1, which are times recorded in the same reference system. If the recording tape is running to the left, T3 will be recorded to the right of T1. Or we might imagine that the recording device uses a system of concentric circles, with later times recorded in circles 'further out' than earlier times. This would make the order of recorded times topologically as well as quantitatively recognisable.

If this is denied - if it is contended that T3 would be earlier than T1, and the mark recording T3 to the left of the mark recording T1, or in a circle closer to the center - then I think we are approaching physical absurdity of the 'killing one's grandparent' kind. Suppose A looks at his tape before sending his message: would he see a mark showing that he has already received a reply? Suppose he then has a heart attack (which would be understandable) and never sends the message at all? If I understand Markus's post #48 correctly, he would see this situation as a necessary result of the Lorentz transformations. If so, I would just see it as showing the inapplicability of the Lorentz transformations in this case. Moreover, if I am right that T3 must be later than T1 in A's reference system, then I think T3 must also appear later than T1 in any other reference system. According to STR, clocks may run at different rates in different inertial reference systems (as viewed from one another) but they never actually run backwards.

Itsme

Active Member
What do you mean by 'Fravor's tic-tac is not in the LIZ'? Are you arguing we have enough information to positively identify it?
With a clear view on the object from a few thousand feet on a clear day, how do you reckon would Fravor be able to positively identify it as something extraterrestrial? What information would give that away?

The model 'interstellar travel is possibile' + 'there are aliens out there' + 'spacefaring civilitazions live long enough' predicts there should be abundant signs of aliens, including numerous colonized worlds and spaceships buzzing around, it should not be difficult to see those signs
What signs would you expect to see?

FatPhil

Senior Member.
... an FTL message ...

According to STR ...

You can't pick and chose subsets of a theory that you wish to hold. Add a contradiction into the mix, and any of your later conclusions can look like paradoxes.

DavidB66

Senior Member
You can't pick and chose subsets of a theory that you wish to hold. Add a contradiction into the mix, and any of your later conclusions can look like paradoxes.
Surely it is common enough in science to have theories or 'laws' which are valid and useful in some circumstances but not others. E.g. Boyle's Law and Hooke's Law are only valid within a certain range of applied forces. Or in fluid mechanics, where theories or equations that work for laminar flow don't work for turbulent flow. Or classical electromagnetic theory, which breaks down for sub-atomic particles (the Ultraviolet Catastrophe). More generally, quantum theory and general relativity are widely considered inconsistent with each other, but physicists seem to live with this by using the two theories in different domains of application. Of course they would ultimately like to unify the two theories, but in the meantime they don't seem too distressed by the inconsistency!

If FTL were proven to occur, wouldn't the obvious pragmatic response be to keep using STR for sub-light velocities, but avoid it for FTL velocities? Once again, I don't believe in FTL velocities, I just don't think the idea can be dismissed by the argument that FTL would involve a violation of causality.

Mauro

Senior Member
With a clear view on the object from a few thousand feet on a clear day, how do you reckon would Fravor be able to positively identify it as something extraterrestrial? What information would give that away?
I don't need to reckon anything, it was you who said "Not all UFO sightings are in the LIZ. Fravor, for example, observed the tictac from a few thousand feet....", not me.

What signs would you expect to see?
From a galaxy fully colonized by aliens, you mean? As suggested in your post #73?

On the hypothesis tthat aliens colonized the whole galaxy I expect to see aliens everywhere, including on our planet, what else?

Yeah, they might be hiding very well (Aliens of the gaps?), while at the same time keeping giving us tantalizing (but always ambiguous) signs of their existence for some mysterious reason ("Aliens work in mysterious ways"), but we are back again to faith-based reasoning here.

Ann K

Senior Member.
Fravor, for example, observed the tictac from a few thousand feet (this was his closest point of approach)
I believe Fravor observed it from what he estimated to be a few thousand feet, but we do not even have enough information to be sure of that distance, therefore we have no way to verify any conclusions he may have reached about size or speed.

Itsme

Active Member
I believe Fravor observed it from what he estimated to be a few thousand feet, but we do not even have enough information to be sure of that distance, therefore we have no way to verify any conclusions he may have reached about size or speed.
I think my wording "a few thousand feet" implied an estimate. And given a clear, wide angle view from his cockpit on a clear and sunny day it is safe to assume Fravor could estimate distance with this accuracy purely from parallax.

Itsme

Active Member
On the hypothesis tthat aliens colonized the whole galaxy I expect to see aliens everywhere, including on our planet, what else?

Yeah, they might be hiding very well (Aliens of the gaps?), while at the same time keeping giving us tantalizing (but always ambiguous) signs of their existence for some mysterious reason ("Aliens work in mysterious ways"), but we are back again to faith-based reasoning here.
These types of analysis are mainly useful to get some idea about the time scale at which an advanced civilization spreading out in the galaxy could be in our neighbourhood. They do not necessarily involve "aliens colonizing the whole galaxy". The estimated time scale is short enough to lead to Fermi's paradox.

The "signs" often are not ambiguous to the witnesses. They are only ambiguous in a scientific sense because we impose rigorous scientific quality requirements to evidence that was obtained during an unexpected transient event in unconditioned circumstances ("exraordinary events require extraordinary evidence").

These rigorous scientific requirements are hard to meet for any unexpected transient event, not just UFO sightings. Example: I just saw a crow fly by. It's impossible for me to provide undisputable scientific evidence for that. Even a picture won't suffice, nor other witnesses who claim they saw it, too. You are only inclined to accept my story because you already know crows exist. And you are inclined NOT to believe me if I told you the crow was white.

The 'evidence' is inevitably scientifically ambiguous in both cases, simply because they both are unexpected transient events. Your acceptance of the existence of black vs white crows makes the difference, not the ambiguity of the evidence.

If we somehow already knew of the existence of extraterrestrial intelligences and their capability to visit us, nobody would complain about the ambiguity of the evidence and use that as an argument for the non-existence of such events. They would just be "black crow stories". But we see these events as "white crow stories", i.e., "extraordinary" because of arguments like the ones proposed by Brian Dunning. I think the discussion in this thread has shown that these arguments are not as iron-clad as they seem.

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JMartJr

Senior Member
Fravor could estimate distance with this accuracy purely from parallax.
Without knowing the size and speed of the object, I'm not sure how that would work.

Scaramanga

Member
This is Brian Dunning's new article, received today in the Skeptoid Companion. It's about his upcoming independent movie on the topic, and is a good discussion of the practical aspects of UFOs as well as skepticism in general.

In the movie, we talk to astrophysicists and astrobiologists who explain that the laws of physics are not laws that human scientists made up. They are observations grounded in physics equations, and math is math, everywhere in the universe. We look at how we've been able to verify that the laws of physics today are the same as they were billions of years ago, and how we've been able to verify that the laws of physics here are the same as they are on the other side of the universe. Math is math. The aliens' math will give them the same answers that our math does. If you try to brush that aside with the illogical "The laws of physics don't apply to aliens," then you've abandoned our shared goal of better informing our beliefs with science. Instead, you're informing your beliefs with the magic of leprechauns and genies.
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The laws of physics demand that when a UFO appears, the observer has to have the worst camera possible, with the worst possible settings, worst possible focus, and preferably most gullible photographer. That is the most tried and tested law of physics of all time.

JMartJr

Senior Member
That is the most tried and tested law of physics of all time.
I suspect Bigfoot has a slight edge there.

NorCal Dave

Senior Member.
These rigorous scientific requirements are hard to meet for any unexpected transient event, not just UFO sightings. Example: I just saw a crow fly by. It's impossible for me to provide undisputable scientific evidence for that. Even a picture won't suffice, nor other witnesses who claim they saw it, too. You are only inclined to accept my story because you already know crows exist. And you are inclined NOT to believe me if I told you the crow was white.

The 'evidence' is inevitably scientifically ambiguous in both cases, simply because they both are unexpected transient events. Your acceptance of the existence of black vs white crows makes the difference, not the ambiguity of the evidence.

Hmmm. I would think the standard default position when dealing with "ambiguous" information is to compare it to less ambiguous information. In your example of the crows, yes I would likely take your word for it that you saw a black crow as there is overwhelming evidence for the existence of crows and crows are almost always black.

However, if you simply told me, you saw a black crow, I might want to further disambiguouize (?) by asking about the location you saw the crow. For example, something I only learned recently, if you say you saw a crow in my yard, you in fact more likely saw a raven. Close but different.

If you say you saw a crow in the Portugues Azore islands, I might be more hesitant to take your word for it:

​

The following tags have been used to highlight several categories. The commonly occurring native species do not fall into any of these categories.

• (A) Accidental - a species that rarely or accidentally occurs in the Azores
• (E) Endemic - a species endemic to the Azores
• (I) Introduced - a species introduced to the Azores as a consequence, direct or indirect, of human actions
• {Extinct} Extinct globally - a species that no longer exists

Crows, jays, and magpies​

Rook
Order: Passeriformes Family: Corvidae

The family Corvidae includes crows, ravens, jays, choughs, magpies, treepies, nutcrackers and ground jays. Corvids are above average in size among the Passeriformes, and some of the larger species show high levels of intelligence.

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Crows are listed as accidental A, so maybe you saw one or maybe you were mistaken. Certainly possible, but uncommon. Is it more likely that you saw something else and thought it was a crow? Some other large mostly black bird that is more common in the Azores?

Now if you said you saw a white crow, we have a similar situation. We have overwhelming evidence for the existence of black crows, but we know albinism occurs in most species, so an albino crow is possible, though rare like a crow on the Azores. Is it more likely that you saw some other white bird that you mistook for a white crow? A seagull perhaps?

Likewise, as we have seen, many, many reports of UAPs have turned out to be mundane things that were misinterpreted. Lots of seagulls that were thought to be white crows, if you will.

If so, then we want to eliminate all the seagulls first, before accepting the very possible, white crow.