Young astronomer captures a shadow cast by Jupiter

By Phil Plait | November 18, 2011 11:00 am

Shadows are created when a source of light is blocked. Obvious, right? Also obvious is the brighter the source, the easier it is to see the shadow cast. So you might wonder, how faint an object can you use as a light source and still be able to detect a shadow?

We know the Sun and Moon cast shadows, and Venus is well-known for this as well. The entire sky is bright enough, even at night, to throw shadows under the right conditions. But what about the next brightest light source in the night sky: Jupiter? There have been claims for decades (I found one from 1905!) but I’ve never seen any proof.

Canadian "amateur" astronomer Laurent V. Joli-Coeur wondered about this as well. So he set about dreaming up a way to do it: build a rig that would allow him to set up a "Jupiterdial" — like a sundial, with a gnomon (a post) that would cast a shadow, but which he could aim at Jupiter — and take a time exposure on his camera.

So with some help, he built it… and it worked! Here’s the result:

The hammer-shaped shadow is from his gnomon, and the light source is from Jupiter. To make sure, he rotated the rig a bit, and the shadow moved as well, indicating it was from a point source. Also, he pointed his rig well away from Jupiter and got no shadow when he took a third picture, showing it wasn’t from the glow of the night sky, either.

All in all, a very well-done, proper scientific inquiry.

Oh — did I mention that Laurent was 14 years old when he started this project?

Amazing. When I was 14 I was deeply into astronomy and had my own ‘scope, but I was nowhere near this sort of thing. Sure, tech is a lot better now and all that, but clearly Laurent is very clever, and has a bright (haha) future ahead of him. He’s taken some very nice pictures, too, including one of the crescent Moon I like quite a bit.

If you watch the news it’s pretty easy to despair for our future. But it’s really important to remember that there are smart kids out there who will grow up into smart adults. The future is in their hands, too. A kid today such as Laurent who shows such curiosity and the desire to explore boundaries will make a fine inhabitant of that future.

Tip o’ the dew shield to Russel Bateman on Twitter

CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

Comments (35)

  1. Joel

    Impressive stuff. It’s always amazing when young people can come up with something brilliant like this at all.

    Without wanting to denigrate his achievement at all, I notice he used a five-minute exposure for the photo. Would such a shadow be visible to the naked eye under the right conditions?

  2. Scott Rivers

    Bet his teachers are mighty freaking impressed.

    Quite the smart kid. :)

  3. Dragonchild

    Guh. These stories always fill me with a sense of guilt. I was also already very interested in astronomy at 14, but back then I considered an ambitious accomplishment to be catching a glimpse down the class hottie’s shirt without getting caught.

  4. Yay smart kids!
    Hope for humanity after all.

  5. Wzrd1

    And without any high tech solutions! Just a question, a concept and creativity and a scientific proof of the phenomena.
    It DOES give one hope for the future.

  6. STEVE

    You may think you’re tipping your dew shield to ” Russel Bateman on Twitter”

    but you’re actually insulting him by spelling his name incorrectly.

    It’s Russell Bateman.

  7. Kathy King
  8. ABC Dário

    Great job!

    It also makes me think about how many kids (boys and girls) are out there, who if given the chance (i.e. not having to worry about things such as where to get the next meal), would be able to demonstrate how much ahead they can get (in Astronomy or other lofty goals).

  9. Daniel J. Andrews

    Heh! Brilliant. One of those “Why didn’t I think of that?” type things that only seem obvious after someone else has already come up with it. Bien fait, Laurent.

  10. When I was 14 I was busy looking at the lingerie pages in my mother’s catalogs.

  11. Mary

    Never tell kids there are things they can’t do. Sometimes, we just have to encourage them and then step out of their way. Every once in a while, one will have an adventure, like this one, and graciously let us tag along.

  12. Eduardo J

    That is so cool, I am very impressed.

  13. Julie

    I’m curious now– is it possible to capture a shadow cast by the ISS? It’s brighter than Jupiter in the sky, but as quickly as it moves, would it be something that could be caught on film?

  14. Sili

    Bet his teachers are mighty freaking impressed.


    I’m pretty sure photographing the shadow of Jupiter isn’t on the test.

  15. de-vilish-sly

    Phil– the URL for “Here’s the result:” is wrong — Jupiter should be capitalized, as only befits the King of the Planets. Here’s the correct URL:

    BTW– he got *your* URL right.

    Aside from that, love your blog. How many stars should you give an astronomer’s blog?

  16. Chris

    Oh there is hope for humanity after all!

    I wonder if there is an official definition for casting a shadow. Otherwise you could have an arbitrarily dim source and just integrate long enough or have very sensitive detectors and theoretically you would always see a shadow.

  17. Mark Kawakami

    For years I despaired at how dumb today’s kids seem. Then over the last few years, I’ve been reading article after article about astonishing things high-school students have done: Building robots that beat robots from M.I.T., discovering planets, finding a new way to detect freakin’ Ebola!

    Maybe the dumb kids these days are dumber than they were when I was in high school, but that’s probably just observation bias and the curmudgeonly ways that develop naturally in one’s 30s. But I’ve become convinced that the ones that are clever and curious, like Laurent here, they’re so much smarter now than I ever was. The only thing that can hold them back are the dumb choices being made by my generation.

  18. Wzrd1

    @ABC Dário, #8, it is NOT of consideration as to where the next meal comes from at all. Indeed, most frequently, the greatest thinking, reasoning and solutions COME from said situation.
    A situation I’m intimately acquainted with, as well as with said solutions.
    @Mary, #11, like hell I won’t tell them what they can’t do! BUT, I also provoke them into FINDING a solution and proving me wrong, with my greatest praises. It worked QUITE well with our children and other children we mentored.
    Kids HATE to be told that they can’t do something, their independence drive forces them to prove that they’re independent and “smarter”.
    It’s HOW you tell them that they can’t. Not forbidding it, but telling them that it has not been done and it’s unlikely they would find it, but “go for it”.
    And supporting the hell out of them the entire way, silently and passively (until asked for help).
    @Mark Kawakami, #17, it’s a bit of BOTH. SOME of it is observational, some is methodology, some is misinterpretation, a fair amount is truth.
    The MINORITY are worthy as creative persons. The remainder are the typical general populace. If ALL were brilliant scientists and engineers, the society would collapse.
    I just turned 50. To say that my view is curmudgeonly is to be generous. BUT, I LOVE to be pleasantly surprised, such as as this young man has.
    As for dumb choices, EVERY generation is loaded with them. We clean up our parents mistakes and move on, learning (hopefully) from them.
    One can only strive to make the world a BIT better overall during one’s life. Humanity HATES major changes, major changes are typically marked in lifeform experiences on Earth by the brevity of life. As the physically weakest species on the planet, change is something that tends to be resisted.
    I’m rather the exception, due to experience. Over 27 years in the US Armed forces, eventually reserve. I changed careers 5 times over my half century of life. I’ve watched the military change SIGNIFICANTLY and embraced MANY of the changes (a few were totally proved false, some years after I and my peers stated they’d fail, such as the stress card (would the ENEMY respect a stress card?)).
    When we were offered platoon element UAV’s, I suggested that the learning curve would be harsh, due to information overload. I also explained flaws in certain new intelligence gathering automation that was proved correct by an SF operator. We thought the same, due to our career paths, as I was formerly in his boots…
    BUT, I didn’t reject it, even IF it was a change, because it gave more information.
    Most people I’ve met over the decades WOULD reject it.
    “It’ll never work, too many moving parts.”
    But, cutting my teeth in the heat of the cold war, watching Kennedy get shot dead live on TV, living through other incidents that cannot be disclosed under Ronnie Reagan, I fully understand and respect Star Trek 6 in two quotes, “You don’t trust me, do you? I don’t blame you. If there is to be a brave new world, our generation is going to have the hardest time living in it. ” and “Spock says this could be an historic occasion, and I’d like to believe him, but how on earth can history get past people like me? ”
    I prefer to consider that history will move forward BECAUSE of people like me, those who LEARNED. :)
    Or as another “doctor” said, “You can be SO much better!”…
    So, MY question is WHY *WON’T* you try?
    Lead, follow or get the hell out of the way! :)

  19. Messier Tidy Upper

    By Jove that’s well done! 😉

    Congrats, Laurent V. Joli-Coeur. :-)

    Very superluminously impressive indeed. Tres magnifique. :-)

  20. Infinite123Lifer

    I have been watching Jupiter light up the sky for the past 2 months. It is incredibly brighter than Vega with my eyes here in the Northwest. I would not be surprised at all if the young & bright Laurent captured a shadow from Jupiter. It seems like Jupiter has kept me from falling over my dark brown stairs on the way into the house more than once or twice with its shimmering self in recent memory.

  21. alfaniner

    Geeky moment. The first thing I noticed in that picture was the font on the poster behind him. It’s a Star Trek font.

  22. Chas, PE SE

    So: A million years ago, four hydrogen nuclei fused into a helium nucleus, releasing a photon or two of energy. This photon worked its way up through the Sun’s mass, until it reached the photosphere. Then it leapt out into space. Twenty-two minutes later, more or less, it bounced off a methane molecule in the lower right quadrant of the Great Red Spot. Fifteen or so minutes after that, it entered the atmosphere of a small blue dot. Here its course was deflected slightly. It passed a molecule’s-width away from a solid object comprised of the pulped remains of a structure composed of cellulose. Then it struck a flat surface composed of a semi-reflective composite of inorganic molecules. From here it was reflected into a curved, clear plastic device, where its path was bent until it reached a semi conductive surface with enough of its companions that its energy, when released, generated a minute electrical current. This current interacted with other doped silicon semiconducting atoms, allowing more current to pass. This current changed the state of the material in an “SD” card, which was subsequently called up by a computer, inserted into a webpage. This image, projected onto the semiconducting surface of a flat-screen monitor, released more photons, which passed through the organic material making up the lens of my eye, through the aqueous mater to the optically sensitive cells making up my retina, to the optic centers in the back of my head, thence to the frontal lobes, being re-converted into ideas. Okay, got it.

  23. And deja vu as I read a searching and intriguing post that makes me want to buy the writer a beer and ask some pointed personal questions… and I look up, and it’s Wzrd1.

    Seriously, is the Dos Equis guy your brother? 😀

  24. @22 Chas: And the amazing bit is, when you think about it, that’s actually the simple version*.

    The world is just awesome :)

    * (For one, you entirely left out the path that the digital information from the SD card took as it was loaded onto a computer, changed into a compressed .jpg image, sent through a home broadband connection through a global system of routers and fiber-optic lines until it arrived at a server where it was archived and then took any number of paths along the same global network until it reached a bunch of home computers whose software requested it. )

  25. Infinite123Lifer

    For Chas, PE SE & Joseph G @24:

    Yeah, but what’s really going on? 😉

    Wish my brother was the Dos Equis guy. 😉

  26. Chas, PE SE

    24 Joe: Yeah, but it was already too long, my fingers were tired, and that takes less than a nanosecond.

  27. @26 Chas: While we’re at it, let’s look at exactly how conductors pass electrons 😉
    I think Phil is entirely right, though: not knowing is overrated!

  28. Nigel Depledge

    Mark Kawakami (17) said:

    For years I despaired at how dumb today’s kids seem. Then over the last few years, I’ve been reading article after article about astonishing things high-school students have done: Building robots that beat robots from M.I.T., discovering planets, finding a new way to detect freakin’ Ebola!

    Maybe the dumb kids these days are dumber than they were when I was in high school, but that’s probably just observation bias and the curmudgeonly ways that develop naturally in one’s 30s. But I’ve become convinced that the ones that are clever and curious, like Laurent here, they’re so much smarter now than I ever was. The only thing that can hold them back are the dumb choices being made by my generation.

    Hmm, it seems to me that this youngster is smart, but not extraordinarily so. What makes him extraordinary, to my mind, is the amount of GOYA* he has demonstrated.

    * = Get Off Your erm … backside.

  29. Maria

    @17 I suppose that stupid kids (and adults) have always been around. it’s just that now they get to have their stupidity recorded and broadcast for the ages. The media wouldn’t be able to exist without them and once something is out there, it’s out there forever so all of these actions and events pile up. They get ingrained into our media and cultural landscape, a sort of background of sorts.

    As to this kid, I wish I had been so motivated, focused, and astute when I was that age. Hell, I should be that motivated, focused, and astute now. Awesome work.

  30. anonymous

    Haha this kid goes to the best school in his province.
    All of the kids that go there are just so brilliant, one discovered something in cancer, idk…
    Kids that go to that school are our bright future, there is hope. they are amazing, simply BRILLIANT

  31. Fahim

    I was a member of one of the judging teams that examined your scientific project during the Canadian scientific competition in PEI (May, 2012). My task, as a judge, was to examine nine scientific projects altogether in that competition. As soon as I read your project report, I realized that it was of a superior caliber that set it apart from the other projects that I was examining. From your written report, your gift was readily transparent. I knew even before I had the chance to meet you in person during the judging day that you had a big chance of winning the Grand prize. And you ended up doing just that! Congratulations! You earned it.

    I have no doubt that this great mind of yours will achieve other great things in the future.

    Bravo, travail bien accomplis, Laurent !

  32. Laurent V. Joli-Coeur is a grade 3 student at Collège Jean-de-Brébeuf in Montreal, Qc, Canada.

    Congratulation to his teachers and more particularly Mrs. Sonia Saumier and Mrs Louise Lamothe.

  33. Georg

    “shadow cast by Jupiter”
    Who is to blame in English? Who is the “castor”?
    The light source or the stick?
    In German we always say the stick casts the shadow.


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