How worried to be about asteroid 2024 YR4

A student visited my office today asking about an asteroid she heard about in the news.  As though we needed something else to worry about, right? NASA now predicts a roughly 3% likelihood that asteroid 2024 YR4 will hit our planet.  On Dec 22, 2032, YR4, a football-field sized asteroid travelling around 17 km/s, will reach us and hopefully miss.

Students are usually surprised that we can predict the arrival of this body with so much precision (the exact date) so long in advance.  What makes it relatively easy to do is that the asteroid is on an elliptical path around the Sun.  All other bodies have little to no influence on it.  Knowledge of the asteroid's position, speed, and direction at any moment enables us to predict its future trajectory around the Sun with great accuracy.  The 'when' of it is extremely precise, but the 'where' of it has some uncertainty, hence the 3% chance.  For now, we can draw an area of a certain size in space that YR4 will shoot through on Dec 22, 2032, and Earth will fill a small portion of that space at that time.

The amount of energy carried by an asteroid is the key metric for assessing the level of damage its collision with Earth would cause.  The energy is usually expressed as 'equivalent to X megatons of TNT explosives', which does nothing to calm fears that the public may have.  The good news regarding 2024 YR4 is that it would collide with an energy equivalent to about '10 Megatons of TNT' (that is 10,000,000 tons, but still about 100,000 times less than the one that marked the end of the Jurassic).  

Though this is not an extinction sort of asteroid, the press has called it a city killer, because it needs to sound at least a little scary.  But the term is also appropriate, because the footprint of destruction were this asteroid to strike Earth would be in the area of 2,000 square kilometers, which is bigger than most cities.  I mean, even 1 ton of TNT is not something I'd want to set off in my backyard, so 10,000,000 of them sounds like it very well could level a city.

So, what do we do?  For now, we wait, and keep monitoring it.  With more precise data, the likelihood could eventually reduce to 0%.  The trouble is, in the unlikely event that the odds increase dramatically, a plan will need to be made and launched in a hurry.

Will the plan involve Bruce Willis and nuclear bombs being detonated from inside the asteroid?  Sadly, no.  Not only is this a way more impractical option for many reasons (like, nukes in space, what could go wrong?), we also could not be completely sure of its outcome.  A more elegant approach would be to launch a large rocket right into YR4, to change its course at just the right moment (small changes of direction lead to large deviations later in a trajectory).  This approach has been successfully tested before: NASA's DART mission successfully deflected an asteroid larger than this one in 2022.

The tricky part is determining when or if to 'pull the trigger'. DART cost over 300M USD, so it is not something to undertake just for fun (though it does sound extremely fun!).

How much should we worry?  Not much, for now, but we will take a very careful look at YR4 when it passes our neighborhood of the solar system next in 2028, and reassess.  Still, it is nice to know that we have a plan that has worked in the past if YR4's trajectory gets too close for comfort.

Viral Fake Physics Videos

I have spent most of my career with an eye towards fighting science misinformation.  This has been a losing battle, of course, but one I feel a duty to see through.  Typically, I take aim at outlandish claims made by people with hidden agendas, from classics like "Burning fossil fuels does not contribute to climate change" to "Just wear this bracelet and your ailments will disappear."  Those hits keep on coming, but there is a new kid on the block that really has me scratching my head.

As 2025 begins, there has been a sudden uptick in the number of fake physics videos appearing in my social media feeds.  Fake physics videos are not to be confused with deep fakes, which involve AI.  In these fake physics videos, we have random people setting up what look to be legitimate physics demonstrations.  They lay out spoons and batteries and suddenly a coin appears to levitate.  In the next, they show a collision between marbles that appears to defy Newton's laws.  After some digging, I discovered that the former uses a camera trick and the latter hides a magnet in some of the spheres.

I am a bit dumbfounded over this... I despise the traditional McScientists who seek to disinform people, but at least I understand that foe.  They have a purpose, misguided though it may be.  Like, the way a wasp buzzing around your head is just an unfortunate manifestation of nature, so too are McScientists.  But what to make of this new thing?

There are so many excellent physics videos out there.  The best of them show an experimental setup, allow the audience to formulate a prediction on what will happen, then run the demonstration, and finish off with a clear explanation of the physics principles at work.  Veritasium and The Slow Mo Guys are two of my favourite YouTube channels containing countless videos of this sort.  The take home message is that physics is fascinating.  Nature, without trickery, is mind-blowing on its own.  What purpose does misleading people about science serve?  Like, "I have them questioning Newton's Laws!" or "Now they'll learn physics wrong, hah!"

When you stop and think of it, magic shows are similar to this.  Whether it is sleight of hand or another illusion, magic always seeks to leave audiences surprised by what they are seeing.  But there is an important difference: in a magic show, the whole premise is "I am going to try to fool you, see if you can spot how."  The audience is, effectively, in on it.  And besides being (sometimes) entertaining, magic shows test the audience's critical thinking.  Fake physics videos are posing as the real deal.  If they began by stating, "The demo you are about to see has been faked in some way, see if you can figure out how," I could get on board with that.

I'm proud that I was able to spot that these videos were disingenuous. If I'm being honest, I kind of enjoyed debunking them.  I'm even tempted to show them to my students.

But I still don't understand the motivation for making the videos.  Is it just for attention? It is, isn't it?  Geez.  The twenty-first century is no time for an idealist like me.  

Escaping a Crazy Semester

It has been a long semester for so many reasons.  There were so many distractions outside of the classroom - too many to list.  Civil unrest around the world, marches in the streets, a provincial government cutting budgets and enforcing exhausting laws.  On top of that, my lab was situated in a loud construction zone, so I could not hear myself think, let alone communicate with my students... I sometimes must remind myself that we reside on a celestial spec sailing through the cosmos; it helps me remember to keep life's small nuisances small.  

What I know for sure is that time spent with my class in my classroom is my refuge and an escape from the worries of the world.  I decided to celebrate the end of my mechanics course this morning by setting up and running a 'Physics Escape RoomTM'.

This semester's escape room was Christmas-themed

For those less nerdy than me and unfamiliar with Escape Rooms, they are enclosed spaces where participants need to decode many puzzles to eventually escape in an allotted amount of time.  My wife and I have spent countless hours in these rooms; our intensity and determination to succeed often scares the friends who join us.  

My escape room is a bit different than the regular kind, in that there are fewer logic puzzles, and more physics scenarios with unknowns that can only be solved by applying physical laws.  It is a fair bit of work to set these rooms up, but it serves as a great review of what my class learned in Mechanics class this semester, and ends it off on a fun note.  Many students expend so much energy feeling anxious about performing well in college, that they forget to ever have fun.  I would argue that if you can learn while having fun, you will remember those things for longer.

My students feel trepidation over the final exams that are around the corner.  On top of teaching physics, I often feel like a councilor or life coach, urging them to take care of themselves, take deep breaths, and not to overstress.  Just like an escape room, to succeed in final exams, you need to strike a balance.  Success is arrived at by students who are a bit stressed (enough to be continuously engaged) but not so stressed that they cannot focus on the task at hand.

I got the idea to create escape rooms for physics years ago.  I always enjoyed escape room challenges that went beyond code breaking.  I liked when prior knowledge of things, like chess for instance, could be called upon.  Like, your knowledge becomes this superpower that is valued by your group.  I want my students to feel that way about physics.  Throughout the semester, they have developed new ways to see the world, and they should feel empowered by their new knowledge and ability to analyze nature.

Lab Layout in Mechanics Escape Room

When I was in college, I had a biology class where many stations were set up, and you could spend 15 minutes, say, observing a station and drawing conclusions, like a bunch of mini labs.  This was way more interesting to me than one long lab where you measure this, then that, then change this and re-measure, etc.  Those labs are necessary, but they can get boring after a while.  As seen above, demo stations form the basis of a Physics Escape RoomTM.

Another difference between traditional escape rooms, which have one team at a time, is that my room has many teams competing to get out first.  This year, three teams managed to escape the room in the 1 hr 15 min time allotment.  To their dissappointment, no bonus points are awarded for getting out first.  Still, the top team in each section happily posed for a pic afterwards to be featured in The Engineer's Pulse.

Group 1 victors (left to right): Xavier, Amélia, and Luc

[notice the hole in the ceiling at the top of this photo - with all the work going on in and outside of our lab this semester, I am just pleased that no student fell through the floor]

  

Group 2 victors (left to right): Nicholas, David, Avoy, and Trong-Don (missing from photo: Malik)

Dear my beloved Fall 2024 mechanics students, whether or not you physically escaped the room today, you have completed the semester, and I hope you found it to be an enriching experience.  Now it is time to lock yourself in a different room and study ;)

Good luck on your finals!

'Orbital' has left me breathless and musing about weightlessness

The summer is half over, but the winner for my top read has already been determined.  Orbital: A Novel, by Samantha Harvey, has enraptured me.  It is a story about one day in the lives of a crew of six astronauts in low Earth orbit.  We orbit with them, experience sixteen sunrises and sunsets, perform weightless tasks, but mostly, follow their inner monologues, which I would describe as meditations on nature and space.

The novel is a love letter to Earth and a prayer that we will learn to inhabit it with grace.  Harvey describes the daytime view of Earth as "... the humanless simplicity of land and sea.  The way the planet seems to breathe, an animal unto itself.  It's the planet's indifferent turning in indifferent space and the perfection of the sphere which transcends all language."

Summer is a wonderful time to read this book.  One thing I've always enjoyed about physics is how it opens up amazing conversations during late evening strolls, when the stars come out.  At such times, with the Sun blocked out, we see the vastness beyond our atmosphere, and feel so very small.  This sense of awe overcomes us.  Orbital gives us this same feeling, but from a privileged vantage point some 400 km above our planet.

Many students have asked me if I would like to travel to space, and I tell them there's no point thinking about it because my wife wouldn't let me.  The truth is that while I would love to see Earth with my own eyes from low Earth orbit, I do not think my body would enjoy the experience of weightlessness.  Most amusement park rides are no-go zones for me now, which totally sucks, because they were a delight before I turned thirty.

It is not possible to experience weightlessness for a significant amount of time in our day-to-day lives, because along with Earth's gravitational force, we are always subjected to some other contact force (like the push of a chair onto our butt, say).  An orbit is a perpetual state of falling; astronauts are falling along with the capsule they inhabit.   The reason satellites don't fall down to Earth's surface is because they have a sufficient lateral speed (many km/s).  A circular orbit maintains its constant speed because there is no atmosphere to slow it down, so round and round it goes.

Okay, quick tangent... Here's a fun little question that just came to me: Standing on the surface of the Moon, with its negligible atmosphere, how hard would I need to throw a rock for it to complete a full orbit and hit me in the back of my head?  A quick application of Newton's second law leads to the result: v = sqrt(GM/R), where M and R are the Moon's mass and radius, respectively (G is the universal gravitational constant).  Plugging values in, we get a speed of 1,680 m/s (over 6,000 km/h).  I can't throw that fast, and in any case, would prefer not to get hit in the back of my head by a rock moving that fast.

Let's get back to the feeling of weightlessness.  When you jump off of a diving board, you feel weightless from the moment your feet leave the board up until your body enters the water; a few brief seconds of weightlessness.  I cannot fathom enduring that 'organs floating in the ether of my rib-cage' feeling for days, weeks, and even months, without a break, as astronauts do.

There really is no way to simulate weightlessness on Earth.  Even skydiving does not replicate the sensation, because we quickly reach terminal velocity, where the upward drag force matches the downward weight force.  Yes, we are falling, but we feel our weight.  As far as your innards are concerned, it's like lying flat on your bed, only it is the air giving the steady upward push.

A compromise between the brevity of diving into a pool and, say, a 90-minute complete circling of Earth in a spacecraft, is a zero-g airplane, which cuts off its engine for about 22 seconds, during which its thrill-seeking passengers float around the cabin.  It then repeats the parabolic maneuver many more times until someone pukes.

I guess I will have to be satisfied with musing about space.  For this earthbound physics teacher, reading Orbital will have to suffice.

Wishing you a summer of blue skies and starry nights.

Totally Stoked for Totality!

For readers far away from the path of totality for the upcoming solar eclipse, my apologies, but as a Montrealer, I will be getting one minute in the full shade of the sun on Monday, April 8.  It is truly a once-in-a-lifetime experience, and I am excited to the point of losing sleep.  It inspired me to write this extended piece in the Montreal Gazette: Totally Stoked About Totality.

Totality will occur at 3:27 p.m. for Montrealers.  But as we are on the northern edge, it will be shorter than those along the middle of the path by a couple of minutes.  Still, one moment would be sufficient to sear the event in my memory.

I was inspired to write the piece by a colleague of mine and my feeling that the average person is not as psyched as they ought to be.  The one message I want to convey to anyone that has an easy opportunity to enter totality is this: DO IT!  The worst case scenario is that this few minute commitment does not rock your world, but in all likelihood, it will be unforgettable, and more so if you experience it with loved ones.

*** Remember to protect your eyes.  Wear eclipse viewing glasses whenever looking directly at the sun, with one exception: the brief minute of totality.  You must remove them during the big moment or you'll miss it.

My Fall Mechanics Class - thanks for the escape!

Oftentimes, as the end of year draws near, I take a moment to reflect on its high points.  For me, there were several, most notably, the publication of my first book (Getting Physics: Nature's Laws as a Guide to Life, link on the right side of the page, makes a great Christmas gift, wink wink).  But, this year has been a rough one for me, particularly the past couple of months, for many reasons I will not elaborate on, but if I must list a theme, let's go with 'targeted attacks on minority communities'.

Of course, I am not alone.  In these difficult moments, we need to try extra hard to be in the moment, and escape the weight of this general malaise.  The classroom is a setting that can offer such an escape.  Many students feel that the classroom is a place they would like to escape from, but consider this...

Many years ago, a student of mine was in crisis.  I could see on their face that something was not right, and we had a chat.  They said something that stuck with me: "The classroom is an escape, a brief respite from my troubles."  I totally get that, particularly with physics, because physics does not care about the day we are having or whether there is peace in the Middle East.  The laws of nature exist outside and above all of our troubles.

In a recent bout with COVID, I was watching too much Netflix, as one does (mostly movies I have already seen cause that's how I roll).  I rewatched Jurassic World.  There are two brothers who enter a theme park with dinosaurs.  One's glee boils over, while the other stares at his phone.  How can one not be completely in awe?  That is how I feel when students get bored in physics class... Not that they all do, but of course, some do.  Maybe most do some of the time?  How can I know for sure?

At the front of the class, I get immersed in physics, and I get to spend time with a fun bunch of young adults.  I get to escape things that exist outside the classroom.  I want all of my students to experience the same feeling.  I have spent my whole career figuring out how to do that while also maximizing their academic growth - and I still have much to learn.

Normally, I say goodbye to my students at the end of the year and inherit new groups in the Winter semester, and try again.  But for my Mechanics class, there was a last-minute reshuffling, and no one could take this group of honours students of mine for their next course (Waves, Optics, and Modern Physics).  In the shuffle, the course fell to me.  

I now have this opportunity (has only happened twice before in my career) to teach the same body of students another course.  I hope they will be happy to hear this news.  My take on it, in general, is that it should be avoided.  Students should see a discipline from many angles.  Also, too much familiarity can be a problem.  For example, students might think it is okay to break lab equipment cause "He's a nice guy, and he knows us," etc.  Anyway, as I said, they are a fun bunch of young adults and I look forward to trying again.  A second chance to get to know the Universe and escape our Earthly troubles in the process.

In the Light of Other Suns

The Eighth Interstellar Symposium, entitled "In the Light of Other Suns" is underway this week at my alma mater, McGill University, in Montreal, Quebec.  Hosted by the Interstellar Research Group and Professor Andrew Higgins, the space conference includes studies of various challenges associated with interstellar flight... and there are many!

Last night, I was fortunate enough to be in a sold out auditorium for a panel discussion amongst experts with varying backgrounds.  The six hundred in attendance sat attentively as a wide range of questions were addressed, from "How much might the transit depicted in Avatar 2 cost?" to "Is it ethical to have a child on a planet that is not Earth, virtually guaranteeing that they will never set foot on their species' origin planet?"  The answer to the former is on the order of petadollars (billions of billions of dollars), and the answer to the second is "We don't know."

The experts have no illusions that people will be travelling to Alpha Centauri in the coming decades.  They anticipate microsatellites being propelled at relativistic speeds (>0.1c) to take pictures of exoplanets in that timeframe.  Starships with people might be a hundred years away.  So, why are distinguished professors studying them today?

The economic answer is that long term projects overcome incremental hurdles that enable spinoff technologies in the present.  But there are so many more reasons, like the plain fact that we are an aspirational species.  NASA technologist Les Johnson, irked by the question of economic returns associated with interstellar flight, posited that humans wanting to know things is reason enough (a comment that elicited enthusiastic applause).

Current engineering studies examine photonic propulsion and the highly reflective surfaces required to reach dizzying speeds.  Others look at the stability of a tiny satellite's trajectory while being bombarded with photons or collisions with space dust when moving at some fraction of c.

I was expecting to hear more about Breakthrough Starshot, the aforementioned mission to snap photos of exoplanets and send them back to Earth.  It seems that the interstellar community is becoming less focused on this one particular mission, instead looking at energy propulsion in a broader sense.  The possibility of a one month transit to Mars was discussed; the spaceship would use a 1g acceleration for the first half of the trip (lasers pushing it from Earth) followed by a 1g deceleration during the second half (lasers pushing it from Mars).  So ya, it would require laser arrays deployed on the Martian surface, but don't worry, studies have looked into the feasibility of that too.

Is it a space symposium for dreamers?  Absolutely.  But power to them (the photonic kind).  A technical engineering conference that can fill a large auditorium is doing something right.      

My first TV appearance!

I'm excited to announce that I will be interviewed by Mutsumi Takahashi on CTV's Montreal noon newscast this coming Tuesday, March 28.  We will discuss my book, Getting Physics, and how I use it to help make physics relatable for students.

I have done radio interviews before, but TV is a new thing for me.  Looking forward to it!

A Thought About Teaching

If we are born a seed, then when I meet students in college, they are plants with deep roots.  On my best day, I can be a star that shines light on the garden before me, inspiring a direction in which to sprout.  If that is not a good reason to get dressed in the morning and go to work, then I don't know what is.

My first book launch

Next Thursday, March 3, 5:00 pm, I will be having my first book launch event at Vanier College (in the STEM Centre, D-301) for Getting Physics: Nature's Laws as a Guide to Life.  I would love to see science enthusiasts there, particularly current and former students of mine. 

I am thinking about how the event should run.  I have been to book signings before and they always include some readings from the newly published book.  My hope is that some of my current and former students could share some of the reading duties with me.  After all, this book was written with them in mind.  The schedule I envision is:

5:00 - 5:30 pm: hors d'ouevres and schmooze

5:30 - 6:00 pm: speeches and short readings from book

6:00 - 6:30 pm: book purchase and signing

My college issued a press release yesterday, so I am also hoping to make the rounds with local Montreal media.

It will be my pleasure to share this moment with readers of this blog who happen to live in my city.  There will be no book tour, so I am contemplating ways to reach a wider audience.  For now, I am starting with my stomping grounds, and seeing where it goes from there.