Ask the Dreadlocked Science Geek

[dreadgeek]

So a couple of people have expressed a wish for an "Ask Aj" thread where they could post their scientific questions. Now, I may not always have an answer for you off the top of my head but I will always try to get you the *best* available answer even if that means having to do a little bit of research.

So if you have a question about some subject that has to do with science OR if someone has said something to you that seems like it just doesn't quite add up and you suspect there may be a glaring logical fallacy OR if you have a question about skepticism ask away!

Cheers
Aj

[IrishGrrl]

ok yes..yes I do.

So, about ghosts.

What do you make of EVP's?

Objects moving on thier own? (I have seen this myself in my own house so I know it's not a prank)

Aparitions?

What do you think about the "scientific" meters used to show "proof"?

[dreadgeek]

Originally Posted by IrishGrrl

ok yes..yes I do.

So, about ghosts.

What do you make of EVP's?

Objects moving on thier own? (I have seen this myself in my own house so I know it's not a prank)

Aparitions?

What do you think about the "scientific" meters used to show "proof"?

So, Electronic Voice Phenomena. I have yet to see an example of EVP that cannot be more economically explained by our brains seeking patterns. Remember that your brain is a pattern-seeking machine. I think that EVP is an example of one of two common brain phenomena:

A) Apophenia--which is seeing meaningful patterns in what is actually random noise

B) Pareidolia--which is really just a special case of apophenia but largely visual.

A good and common example of paraeidolia is seeing shapes in clouds. Is the cloud *actually* shaped like, say, an elephant? No, but our brains perceive it to be.

So why would our brains work that way? Well, our brains evolved to discern meaningful patterns out of a random world. However, the world isn't *completely* random and our brains are nowhere near perfect at what they do. Our brains are prone to two common errors:

1) False positive (seeing a pattern when there is none)
2) False negative (not seeing a pattern when there is one)

Of the two, false positives are the less harmful. To understand why, imagine you are one of our Pleistocene ancestors on the African savannah. You are in the tall grass and you hear a rustling. Is that sound a lion or is it the wind? Well, if it's the wind but you respond as if it is a lion and, say, run for the nearest tree you're out some calories but you'll live long enough to eat and thus gain those back. If, on the other hand, you think it's just the wind and it's actually a lion by the time you realize your error, you're well on your way to being lunch. Needless to say, being eaten drops your reproductive fitness to zero. So our brains have evolved in such a way that they are prone to both Type 1 and Type 2 errors. Since type 1 errors generally don't cost the person making them their life, our brains have not evolved beyond them. Type 2 errors can be more deadly but not necessarily so often as to actually have selective pressure on them.

EVP is a type 1 error--seeing a pattern or subscribing meaning to random noise. Most EVP aren't actually voices it's *literally* noise in the sense that the signal carries no information but we *think* it does.

Objects moving on their own I would have to know the specifics of the event. I can think of any number of reasons one might perceive an object to be moving on its own and without specifics, I just don't have enough information.

Apparitions are interesting. There's a frequency of infrasound that appears to have a very interesting effect on the human brain. While we can't *hear* it, the vibrations cause a physiological reactions that the brain interprets as fear. Our brains then backfill something in to explain why we are afraid. This might explain 'haunted' houses. Old houses as they creak and settle with the change of temperatures from day to night produce infrasound vibrations which are too low for us to hear but would produce a fear reaction.

As far as the scientific meters, again I'd want to know what it is they are supposed to be measuring. Here's the thing, most times people will mention a 'field' of energy and that's what these meters are supposed to measure. The problem with this is that the meters either fluctuate in a random manner or the strength of the meter appears to bear no relationship to the distance from the source. This is a problem.

EVERY field we have encountered so far is subject to what is called the inverse square law. The simplest formulation of it is this:

The strength of a field diminishes as an inverse of the square of the distance. What that means is that the farther away from the source of a field you go, the weaker the field gets. This happens VERY quickly. So if you start at the source of the field and move away from it then when you are, say, 2 feet from the source the field is *four times* as weak. When you are four feet from the source the field is *16 times* as weak. As far as we know (and we know quite a bit about fields) this holds for all forms of fields--this means that all four forces (electromagnetism, gravity, strong and weak nuclear forces) plus sound all obey this rule. This is a big problem for these measuring instruments. The signal should fall off as a square of the distance but no matter where the Ghost Hunters are in the house the signal is always random. That simply can't be.

I have to leave the office, I'll return to this question when I get home.

Cheers
Aj

[Linus]

Ok, Science Geek, answer this one from a oft-flying traveler:

Why does it feel, at times, like the plane "stops" or "slows" down in mid-air? It's the weirdest feeling but I've been on flights and about half-way there I get this sensation like we're slowing down (like a car in rush hour) and then we continue on our merry way.

[amiyesiam]

Dear Apple owner and Linus too!!

I have somehow managed to set my mouse to have to right click and hit open rather than being able to just click (or double click) on something and have it open. Any clue how to fix this? I have tried and failed.

sincerely
I know there is a simple (&(*(* answer for this

[Linus]

Originally Posted by amiyesiam

Dear Apple owner and Linus too!!

I have somehow managed to set my mouse to have to right click and hit open rather than being able to just click (or double click) on something and have it open. Any clue how to fix this? I have tried and failed.

sincerely
I know there is a simple (&(*(* answer for this

Go to System Preferences --> Mouse. Adjust there. Alternatively, if this is a third party mouse, try to re-install the driver.

[dreadgeek]

Originally Posted by Linus

Ok, Science Geek, answer this one from a oft-flying traveler:

Why does it feel, at times, like the plane "stops" or "slows" down in mid-air? It's the weirdest feeling but I've been on flights and about half-way there I get this sensation like we're slowing down (like a car in rush hour) and then we continue on our merry way.

Okay, this is a really interesting one with two different answers. The reason for the feeling of slowing down is most likely that the pilot deployed the flaps but the feeling of stopping is something else altogether.

Without anything to use as contrast, you cannot tell the difference between constant velocity motion and being at rest. The key here is *constant* velocity. If you change direction then your velocity isn't constant and it doesn't matter what direction that change of direction happens in (up or down, forward or backward, left or right or any combination). This is why, if you are in a car you almost always feel like you are moving because the road surface causes the car to have an up or down motion.

If you're at 30,000 and its at night or over fairly uniform clouds and if the plane is in an area where the atmosphere is being pretty calm you wouldn't have many cues that you are moving for just a moment. Then you hit an air pocket and the plane bounces a few feet--that's all it would take--and suddenly you're aware that you're in motion.

Don't believe me? Right now, you are moving at 17,500 m/h (28,163 k/h) as is everything else on the surface of the Earth. We don't feel like it because the Earth's rotational speed is constant and there is nothing to create drag or turbulence to disturb the smoothness of the ride. The only way we would ever feel it is if the planet suddenly came to a stop. Then everything on the planet not anchored into deep rock would suddenly be moving VERY fast as all of that angular momentum was transferred to us.

*Perfectly* constant velocity motion is not achievable in-atmosphere because of friction but in a vacuum you could certainly achieve it. So why do you have these moments in an airplane? It's because the stall speed of an airliner at cruising altitude is in a very narrow band. How narrow? The difference between level flight and a stall can be as narrow as 20 mph either way at cruising altitude. So at cruising altitude, the pilots try maintain a very stable speed. The motion you detect is from the air current buffeting the plane. If the upper atmosphere were perfectly still and the aircraft maintained an absolutely constant speed, you would not be able to tell that you were in motion at all.


Cheers
Aj

[dreadgeek]

Originally Posted by June

Dear Geektastic -

If we are moving at 17,500MPH, how come when I jump up in the air, I don't end up down the block?

Bewildered,
June

Because the Earth isn't *accelerating*. Remember that the Earth's rotation is constant velocity motion so we don't feel it and are perfectly justified in claiming that, at this moment, we are at rest. When you jump into the air while your vertical velocity, relative to the center of the Earth. temporarily exceeds 10 m/square second (temporarily overcoming the force of gravity) your horizontal velocity is 0. Since neither you nor the Earth are accelerating relative to each other, you land in exactly the same place as you started from. From your reference plane (the surface of the Earth) there is no force moving you horizontally and since a body at rest wil stay at rest until acted upon by another force, you jump up (which has a force acting on you vertically) and land in the same place (since no force is pushing you horizontally).


The situation would change if you were accelerating. To see this, let's do a little thought experiment.

You are on a plane, the plane is accelerating. You toss a ball up in the air, the ball will, in fact, land a bit behind you because the aircraft is moving relative to the motion of the ball. If, however, the aircraft is moving at a constant velocity then the ball will land at your feet.

Essentially, this is Einstein's General Theory of Relativity in a nutshell. If you are at constant velocity (what in technical jargon is known as the inertial frame) then you are justified in saying that you are at rest, no matter HOW fast you may be traveling. As long as whatever it is that you are traveling on maintains the same speed and direction, you can treat your environment as being at rest. It is only if you are accelerating that you will be aware of movement. One interesting side-effect of this is that gravity and acceleration turn out to be the same thing. Right now there is 1g of gravity pulling you toward the center of the Earth. We would be completely justified in describing us as falling toward the center of the Earth at 10 meters per square second. The reason we aren't all in the core of the Earth is that the electromagnetic force is MUCH more powerful than the gravitational force and the repulsion of effect of all the electrons in your body trying to keep away from all the electrons in your chair and in the floor is what keeps us from falling through the Earth. But right now, from a physical point of view, you are accelerating toward the center of the Earth. There's just something that prevents you from continuing the fall. If you were in a completely sealed box and were accelerating at 10 meters per sq sec. there is no experiment you could perform that would NOT lead you to conclude that you were not on Earth at 1 g.

Cheers
Aj

[dreadgeek]

I have to catch up. I don't spend as much time online during the weekend as I do during the work-week so it may take me a bit to get up to speed.

Cheers
Aj