Moon Drift

Based on measurements made over the years by the Lunar Laser Ranging Experiment (LLRE), the Moon is slowly drifting away from the Earth..
at the rate of 3.82 +/- .07 centimeters every year!

However, what if the Moon isn’t moving away from us or at least not as quickly as we might think? What if the speed of light is not Constant but is changing over time? Next year a new experiment hopes to shine some light on the speed of light and help determine whether the speed is constant or is actually slowing down. According to a new theory by Louise Riofio, the speed of light is getting slower at a rate of 1 centimeter per second each year.

Please keep in mind that this is a teeny tiny amount shorter each year. Since light can travel at nearly 300,000 km/s, a centimeter less is hardly noticeable. If true and because this a cumulative effect, this change will be become more noticeable over time. In ten years it’d be 10 cm less distance traveled in a second, in a hundred years it’d be 100 cm less / s. This also indicates that the speed of light might have been much faster in our past.

Moon drift
Photo of the Earth’s Moon taken from my backyard on April 13th 2019 as it drifts away from us

If you shine a laser beam at the Moon and bounce it off the mirror you can figure out how long it takes for the light to get there and back. Spoiler: it’s less than 3 seconds.

The distance to the Moon from earth is roughly 384,400 km
[384,400,000 meters away from us] and the speed of light is 299 792 458 m / s

The time it takes for light to travel to the moon is

384,400,000 m / 299,792,458 m  = 1.2822203.. seconds

Now keep in mind that I’m using a single number for the distance to the moon and that the moon actually gets closer to earth and sometimes further away. At times as close as 356,761 km or it can be as far as 406,555 km [*see moon distance time table below]

It takes about 1.3 seconds for light to get to the Moon bounce off the mirror and then come back to us so that’s another 1.3 s for the return trip. Unfortunately, the distance to the Moon changes based on its orbit. So the time it takes depends on when you measure it and from where on earth you measure it.

Closest: ~356,761 km divided by the distance light travels in one second = 1.1900266.. seconds
Furthest: ~406,555 km divided by the distance light travels in one second = 1.35612150.. seconds

I’m not sure about the precision on this, since I’m rounding the numbers to start with, the precision isn’t really the important part, as much as to know that there’s a range of time that light can take to reach the Moon which is between ~1.19 to ~1.35 seconds.

Despite the fact that the distance changes depending on where the Moon is in its orbit, on average these measurements indicate that the distance to the moon is increasing every year by 3.8 cm but what if the speed of light is not constant? What if the moon isn’t getting further away but the speed of light is actually slowing down? Is this possible and how could we tell?

If the Moon is moving away from earth at this speed then it would have been much closer to us not that long ago assuming that the rate of change is constant and has always been constant. In fact, the Moon should have been too close much too recently for current theories of the age of the Moon. Also we do not know at this point if this is cyclical, will it slow down in ten years or a thousand years?

Only time will tell

Upcoming experiments on the International Space Station may demonstrate whether or not the speed of light is always the same over time. The current hypothesis is that light is in fact getting slower every year, but the experimental data will hopefully tell us whether it’s the same, slowing down or speeding up. The suspicion is that it’s a rate of 1 cm / s per year but what if it’s more? What if it’s less? What effect will that have on the Moon drift rate?

Let’s take a look

If the rate of change for the speed of light turns out to be: 1 cm / s per year

Then this would mean that the apparent moon drift of 3.82 cm each year is actually..

If I understand this correctly, since the time it takes for light to reach the Moon from earth is 1.2822203 seconds (when the Moon is 384,400 km from us) and if the speed of light is slowing down by 1 cm / s then shouldn’t the effect be 1.2822203 cm? So, 3.82 cm subtract 1.28 cm I get 2.54 cm of actual Moon drift. Still on its way but not as quickly as we thought.

If it turns out that the speed of light is slowing down at a greater rate,
let’s say 3 cm / s per year then..

Distance to the Moon in light seconds: 1.2822203 x 3 cm = 3.8466.. cm then the Moon would no longer be drifting away but is in fact drifting towards us!

I might be missing something obvious in these sloppy math estimates and if I am please let me know. For one, I expect that it’s very very unlikely to be a rate of 3 cm/s per year. That would have huge implications for the entire Universe! It makes me wonder if this change in speed is everywhere or if it’s a local phenomena?

When we look upon the Moon today we always see the same side but if we’re standing on the Moon looking back at Earth, the Earth spins and reveals all.

If the speed of light is constant over time (as most of us have thought it to be) then the Moon’s orbit really is increasing at the speed we observe, at least for the time being. At this rate, in a about 50 billion years from now, a month will be 47 days long as the moon locks into the same side of Earth. The Moon will see the Earth spin more and more slowly until it finally stops and shows only one side to the Moon. It is believed that at this point the Moon will stop moving away from Earth as the tidal forces and gravitational drag that caused the drift will have stopped.

If on the other hand what if the speed of light is speeding up by 1 cm / s per year? Then the Moon is going bye bye. It’d be flying away from us at the speed of 4.8 cm each year. Not good, mind you, probably nothing to worry about for few billion years.

One last note, if it turns out that the speed of light is slowing down exactly the same speed that the Moon is drifting away from us, well, that would be super freaky!


Is the Moon moving away from us and when was this discovered?

GM=tc^3 Adventures in Space/Time

Moon distance time table

Apollo Laser Ranging Experiments Yield Results August, 1994

Measuring the distance to the moon with radio waves instead of lasers

The Universe at walking speed

There’s a certain familiarity we all have with how long it takes to get somewhere on foot.  Taking something well known to us like walking, I thought I’d attempt to use this as a measuring stick for the stars. The preferred walking speed for most people is around five kilometers for one hour spent walking (5 km/hr).  I know some fast walkers get up to 9 km/hr or more, but I’m going to use a comfortable gait that we’d want to stick to for long periods of time since walking takes time especially when you have a long way to go.
This week NASA announced that it has found 7 new planets around a small star that is 39 light years away from us. This star and its planets are named the Trappist-1 system.

A friend asked me this week, So, how many years in a light year again?Of course, there is one year in a light year, but what he was inferring was, “How bloody far away is that if we wanted to get there?”

The speed of light is 299,792,458 m / s

At the speed of light, light can travel the distance of 9,454,254,955,488,000 km in 1 year  (9.45 trillion km)  (or 9.454 x 1012 km)
The fastest man made object ever created [on record by NASA] was the Juno spacecraft that was sent to Jupiter.  It got up to the incredible speed of 265,000 km/h.  That’s like Mach 214, but in outer space no one can hear you scream as you go by that fast.

For our fastest spacecraft Juno, it would take ~35,701,132 hours or 1,487,547 days or about 4075 years to travel 1 light year and to span the distance of 39 light years, it would be 39 x 4075 years = 158,925 years for our fastest spacecraft to reach these newly discovered planets!

That’s a long wait to get there.

If we were to drive to Trappist-1 in a car at an average speed of 100 km/hr it would take 10.8 million years per light year x 39 light years  =
that’s 421.2 million years now that’s a long drive.
If you had to walk to the Trappist-1 system (at a constant rate of 5 km/hr without stopping once), it would take over 8.4 billion years for you to get there!

The estimated age of the earth is 4.5 billion years. The estimated age of the universe is 13.8 billion years.

Fortunately red dwarfs like the star in the Trappist-1 system live a long time (estimates are 10 trillion years, although I’m not sure how reliable those estimates really are), but chances are that the star will still be there by the time you get there in 8.4 billions years from now.  Well, that’s assuming it’s moving in the same relative direction as our sun.

Our solar system, and probably most of our neighbouring star systems, are spinning around our galaxy.  It is estimated to take 225-250 million years to do a full turn.  So over a period of 8.4 billion years, our solar system would have gone around our entire galaxy somewhere between 33 to 37 times.
The Juno spacecraft is always traveling at a the same speed after its initial acceleration by rocket or when it gets a speed boost from a ‘gravity slingshot’ around a planet or moon.  However, if the spacecraft we send were to accelerate throughout the first half of the trip, always gaining speed and then it were to flip around and decelerate for the second half to slow down enough by the time it gets there, we could probably get there much much quicker.  This sort of thing might be possible with the ‘impossible EM drive‘, if it works.  A continuously powered engine similar to that might be used to get to our closest stellar neighbours in a couple of centuries rather than 160 millennia.  I’m not sure how fast this ship would get, perhaps at the halfway mark it could be as much as 20% the speed of light?  I’m speculating, I think it depends on how quickly it’s accelerating, but if it’s continuous acceleration then it doesn’t have to be that much.  Of course, some people argue that faster than light travel is possible (even though Einstein thought otherwise).

For us to send a message to the Trappist-1 system, it would take 39 years and then we’d have to wait another 39 years for the answer to come back to us assuming they receive the message and respond back right away.

In comparison, when light leaves the sun and travels roughly 150 million km to hit earth, it only takes 8 minutes to cover that distance.  So for us to talk back and forth with an astronaut near the sun, it’d take 8 minutes each way.

Venus is only 6 minutes away from the sun at light speed and Mercury is only 3.2 minutes!  Mars 12.6 minutes, Jupiter 43.2 minutes, Uranus 159.6 minutes, Neptune 4.1 hours, Pluto 5.5 hours!

Imagine if we turned on a laser beam to signal to the Trappist-1 system.  After turning on the beam of light, it would shine past Pluto within five and a half hours on the first day of the trip but we then would have to wait 39 years before it is seen by someone on one of those planets.  That is, assuming they were looking for it and that there were such an incredibly bright laser beam like that.

If there ever were such a thing as a laser beam that curved in such a way that it followed the curve of the earth’s surface, we could shine a beam around the world.  You know how long it would take for that light to go around the planet and hit you in the back of the head after turning it on?  Roughly 1/10th of a second which is actually quicker than the average blink of an eye (which is typically 300 to 400 milliseconds).

In comparison to walking to a nearby star, how long would it take to walk around the world?  Well, Jean Béliveau left Montreal and visited 64 countries and hiked over 75,500 km in 11 years.  That’s like walking around the earth twice (the earth’s circumference is 40,075 km).

Walking to California from Ottawa (~4,687 km) would take you just over a month of continuous walking without a single break (about 39 days). If you ran all the way without stopping once, you could do it in about 13 days.  Most likely you could only run at that speed for about 8 hours a day. If you’re a super human runner, it would take about 39 days at the same speed (15 km/hr) for a full 8 hours every day. That would be like running 3 marathons every day.  There would be 111 marathons (42 km each) between California and Ottawa. I can’t imagine anyone doing such a thing ever.

Surprisingly, Katie Visco ran just over 5,040 km from Boston to San Diego in 276 days.  That’s the equivalent of 120 marathons in 276 days.  Wow!
You would have to run 8.7 trillion marathons to reach Trappist-1 and to think that Trappist-1 is pretty close to us!  A mere 39 light years (that’s only about 12 parsecs).

The center of our galaxy is estimated to be ~26,666 light years from here (about 8 kpc). A parsec is 3.26 light years, a kiloparsec (kpc) is 1,000 parsecs.
The center of our galaxy is 252,281,692,800,000,000 km (or 252 quadrillion km) from us. That’s just to get to the middle from where we are on one of the arms.  The whole galaxy is about 100K light years across, but our galaxy isn’t even that big compared to the biggest known galaxy.

The “IC 1101” galaxy is about 6 million light years wide (about 60 times bigger and 20,000 times more massive than our milky way galaxy).
There are 100 to 200 billion galaxies in the observable universe. The observable universe is estimated to be about 93 billion light years across (about 28.5 gigaparsecs).

The actual size of the universe is assumed to be bigger and might be infinite depending on who you talk to but that’s for another post.  How long would it take to walk across the part of the universe that we can currently see with our radio telescopes?  I won’t go into the fact that what we see expands over time or that the universe itself is believed by many astronomers to be expanding at an accelerating rate which would make it difficult to ever reach your end point especially if you’re walking.  Of course, you can’t actually walk in space without anything to walk on so we could substitute walking with ‘slow floating at a constant rate of 5 km/hr‘ assuming you never get pulled into a nearby star or such.

Distance of 1 light year times the number of light years to span the observable universe:
9,454,254,955,488,000 km x 93,000,000,000 light years =
8.7924 x 1026 =
~879,240,000,000,000,000,000,000,000 km

divide by a constant slow floating speed of 5 km/hr =
1.75848 x 1026 hrs
/ 24 hrs / 365 days =
20,073,972,602,739,730,000,000 years
It would take 20 sextillion years to walk across the observable universe!

As they say, if you walk a mile in my shoes you’ll end up at the bar. 😉

Free Won’t

From what I understand about artificial intelligence (AI), in particular, today’s known software programs like Google’s DeepMind. The software can learn from the experience of repeating a task, such as playing a game, driving a car, or reading lips.

The more the AI program practices the better it gets and practice it can! By playing against itself over and over very quickly, always learning and improving as it goes. Before you know it, the AI is better at certain tasks than humans are. Not only that, let’s say that one AI program learns something new after repeating these tasks millions of times over, this program can then pass this new learning to all the copies out there playing games, driving your car, or reading lips (or whatever else it might be tasked to do).

It seems clear to me, that the AI program that drives a car must have certain ethical ‘rules’ programmed into it. For instance, a rule such as: “Don’t go crazy and run over every person that you see.” Most of these rules are pretty obvious, and are probably not something the AI would not follow even by accident.

However, what about the more subtle rules? Have these been written yet? Imagine rules for a scenario such as, “When travelling at full speed down a highway and suddenly a crowd of people run in front of the car.” Of course, the default action is to stop.  But what if this distance is less than the breaking distance, and the only other option is to swerve off the road and potentially kill the passengers in the car?  What decision will be made, if any? Is it simply a matter of counting how many will be killed and picking the best option? Is the AI program always going to make the same choice? Are car passengers entitled to override these settings? Can you make these choices in the admin settings or do you have to hack the software? Unfortunately, it seems like the ethics have to be ‘hardwired’ and practically unhackable. For instance, if the ethics routine isn’t verified as ‘secure and working’ the program can’t run.

Of course, this might all be moot. If these AI software programs can be used to drive cars, I’m sure they can just as easily drive war machines. They’re just automatons following instructions. They aren’t ‘driven or motivated’ they’re simply repeating a learning process to perform tasks the best they can.  You still need to define what’s ‘ok’ and what isn’t in the parameters of the program.

Currently, the ethics parameters with rules such as ‘don’t drive into people’ isn’t something that changes as the AI program learns how to master the task of driving.   The parameters of what is ‘ok’ to do or not do cannot be changed by the AI learning software, it is only controlled by the program’s design.  The AI program follows the rules but can’t change them.  However, I could imagine a world where the AI software would be designed to have the ability to learn and improve upon its own ethics routines.  Perhaps these ‘improvements’ would be small incremental changes, but over time, after millions of interactions and experiences, could these routines become something completely different than what it started with?

It’s funny how we expect these AI programs to have better ethics than the average person has but these programs will only be learning based on what we teach them to start with.  If we even bother to teach them anything.  It’s nice to imagine that a self-learning AI program would come across some pictures of cute kittens on the internet and then suddenly ‘learn’ some ultimate truth that ‘love conquers all’ and somehow it ‘knows’ all about right from wrong, but the reality is that the software might not measure these morals the way humans do at all.  For instance, the machines might think organic beings are irrelevant or that some micro-organism in the ocean must be the dominant life form on earth (at the cost of everything else).  It sounds like a crap shoot to let machines figure it out for themselves, not that I wouldn’t want to listen to what insights they might have, but I don’t want my automated car telling me that I shouldn’t be driving my car at all, that I should walk even though it is raining.

Even if we taught these programs to have perfect ethical sub-routines (whatever that might mean).  Will these programs ever have ‘free won’t’?  Can AI really make choices if it isn’t ever given an option to choose?  Sure, a developer might allow a software program to ‘randomly’ do or not do something, but that’s not what I’m talking about. I’m talking about actual choice. The choice to do nothing. If you don’t have ‘free won’t’ you clearly do not have free will. Of course, if the software just does nothing all the time, it’s probably not very good software or it’s conflicted about something and one of the routines will need to be reset or something.

I guess, what I’m implying is that you choose not to do something when part of your spirit says, ‘No wait, despite what I’d like to do, and perhaps am very good at doing, let me reconsider and instead do nothing.’ You can probably visualize a similar situation, for instance, your first reaction after being physically assaulted might be to respond in kind and sometimes well we just react the way we do and hope for the best. We’re only human after all, I know I am.
The thing is though that, just like a learning software program, whether or not I choose to do something, is most likely due to all my previous experiences. You can imagine that an ‘aggressive’ version of who I am might quickly develop if I were always under some physical threat. I might be more prone to swearing or yelling at people for instance.  Even if I started off as a nice peaceful dude, under the wrong circumstances my attitude might change.  Hopefully my ethics would not change no matter what the circumstances, but that sounds more idealistic than realistic.

I imagine it can be argued that AI software programs have no ‘real feelings’ even if programmed to emulate ‘real feelings’.  That’s why machines are so much better than us ‘mere humans’.  Well, that and because computers are so much faster and never make mistakes (unless they’re programmed to make mistakes or simply have mistakes in their code which also sometimes happens).

Just for the record, I’m against any sort of automated killing machines, even the ones that are made ‘by accident’.  Of course, most of the ‘bad machines’ are usually controlled by people.  In fact, to my knowledge all machines are still under the control of people even the ones that run intelligent programs that can read your lips.

What is the best background noise for work?

About 15 years ago I worked in an office with a white noise generator.  It kept an otherwise loud environment filled with many lively coversations to a dull roar.  It worked rather well, to a point.  Pretty quickly your brain tunes out the white noise, it just becomes part of the environment and makes it easier to concentrate on your work. I’m sure some noise generators are better than others.

Noise Generation

However, a white noise generator can also be very irritating for some people.  I’ve read that it can possibly even increase your stress level rather than do what it is supposed to do which is to provide a peaceful and seemingly quiet work space.
My current office has a rather loud ventilation system that blocks out quite a bit of the distracting conversations in the adjacent cubicles.  When the fans turn off, there’s a sudden deafening silence.  It feels strange without the white noise of the ventilation system.  It turns off so rarely, otherwise it runs continuously all day, every day, winter or summer.  Without the vents on, everything and everyone seems so much louder, so much more noticeable.
If I had to block out the surrounding office noise by wearing headphones, I would not choose to listen to most of the ‘ambient’ noise generator apps that I’ve tried.  There are some exceptions of course, but typically for me,  10 to 15 minutes is all I can take of ambient music, after that my skin starts to crawl. I find that listening to music with vocals can be equally distracting.  If I’m reading or otherwise trying to concentrate, Jazz or Classical music would be a good choice.  I tested my album to see if I can actually work while listening to it.  I have to say it really depends on what I’m working on.  If it’s a mostly visual task like working with Photoshop then it passes the test quite nicely.  Ultimately, not having to wear headphones to block out the noise at work would be best.
In my opinion, the best background noise for work would be the natural sounds you hear sitting in the woods among the trees, the birds and the insects.   Far away from the fax machine, the paper shredder and the sound of the ventilation system. Somehow, I don’t think listening to a recording of ‘sounds of the woods’ will help my work environment.  If only we could open a window in our office.  Oh imagine the nuisance of that! There would be no end to it, some of us would want the window to always be open, others for it to always be shut.

So it goes.