Astrophysics is our gateway to understanding just a fraction of the vast realm of space.
For the brightest young minds on our planet, there's a challenge that puts their knowledge
of this realm to the test. It's the International Olympiad on Astronomy and
Astrophysics. Let's dive into this challenge together and see what we can learn from it.
Once a year, the exam gathers students from around the world and serves as a way
to encourage students to study astronomy and also fosters international collaboration. You have to
be a high school student to take part, but the exam covers content you would encounter well
into a university degree on these subjects. This is a copy of the 2019 exam questions.
These questions cover such a broad range of knowledge that to ace it, you need to
be superbly well-rounded in your astronomy and astrophysics knowledge. I was shocked to see
what's near the end of this paper. It's something that sets this exam apart from any astronomy exam
I've ever taken. It's not just enough here to memorize some equations and plug in some numbers.
The last page of this exam is a practical test, meaning you go out at night with a telescope
and have to find real objects in the sky under a time pressure and with an examiner watching you.
That sounds intense. But before we get to that, let's start with a look at the theory questions.
Question one asks for this list of 11 astronomy related events to be put in chronological order.
So what do you think came first? Some options include the discovery of the planet Uranus,
the discovery of the first planetary nebula,
or the first successful measurement of stellar parallax. And then what was the
most recent? The discovery of the expansion of the universe? Viking probes landing on Mars?
Or the launch of the Hubble Space Telescope? In the answer, the first event was the discovery
of the planetary nebula, and the last event was the launch of Hubble. Pause to read the
rest of the order. Question two is about a measurement made in 1919 of starlight that
was deflected from its path by a small angle as it passed by close to the sun.
The amount of deflection is said to be proportional to the mass of the sun and the
distance away that the light passes it, multiplied by a few constants. The question asks if it would
be possible to detect a deflection of light that passed close by Jupiter or the moon. To solve
this, you need to recognize that the distance to be used in the formula is the radius of the body,
and then compare your estimated angle of deflection against the present day accuracy of
this technique, which is 0.1 milliarcseconds. With that accuracy, you would indeed be able to see
light deflected by Jupiter, but not from the moon, as the moon is not massive enough to bend the
light a detectable amount. In 2019, the exam was held in Hungary, and you can see a local reference
in question 6. It is about European satellites, named Sentinel 2, and shows two images taken by
the satellites of a chimney in Hungary, which is the third tallest building in the country.
One image was taken in June, near the time of summer solstice, when the North Pole is tilted
closest to the sun. And one image was taken in December, near the time of winter solstice,
where the North Pole is tilted furthest away from the sun. We are asked to tell
which image is which, or as they say, which date do we expect the shadow to be longer?
See if you can get it. Would the chimney have a longer shadow in June or December?
The answer is December. That's their winter, and the sun elevation is lower in winter,
leading to longer shadows. This question continues on and gets harder and much more mathematical
when students are asked to then estimate the height of the chimney using the shadow length.
It isn't as simple as Pythagoras and instead involves estimating the elevation angle of
the sun using a trig identity and solving a quadratic equation. There's a link in the
description to the solutions document if you want to try it yourself. Other interesting questions
after this one cover the effects of sunspots, the changing brightness of variable stars,
finding the distance to a galaxy cluster based on the velocities of the galaxies inside it,
and seeing if it would be possible to photograph a
Hungarian nanosatellite from the ground before it burned up in the atmosphere.
These questions are hard because they require tricky conversions between units and a seemingly
impossible to remember array of various formulae and equations. The next section of the exam is
more intense, as it is data analysis, with questions that more closely resemble what
research astronomy might look like, sifting through observational data to find patterns.
Someone who works as an astronomer would likely spend their time at a computer
writing programs and processing images of stars or galaxies, often taken by other people using
huge ground based or even space telescopes. A professional astronomer could get away with
never operating a small backyard telescope themselves, unless they wanted to for fun.
But in this exam, that knowledge is essential, and it's actually nice to see,
promoting what sometimes feels like a forgotten art. In Observational Task 1,
you get five minutes to align a finderscope, so that what it shows in its crosshairs is the same
as what you see in the main eyepiece. Then you get ten minutes to observe the planet Saturn.
You have to find and mark the position of Saturn's moon Titan,
and show the orientation of Saturn's rings. I recently got a telescope again,
after years without having one, and relearning how to use it brought back a lot of memories
for me of times when I used to do this often. I couldn't believe how many nights
I had let pass without looking at Saturn, or seeing the things that are right up there.
You don't need a telescope to do that, you just need to be curious
and willing to go outside in the cold. But having to fiddle around with a telescope
forces you to be out there long enough to take notice. Inspired by this exam,
I tried to complete the third task, which is observing the planetary nebula M57.
Other challenges from the exam include finding a variable star in the constellation Cygnus
and estimating the magnitude of two stars in the constellation Ursa Minor just using your
eyes. This exam has reminded me why I love astronomy, but competitive exams do have a
knack for beating passion out of people by cranking up the intensity and making
the pursuit of knowledge about winning rather than about joy or understanding.
I hope that the students who are lucky enough to participate in this event are able to maintain
and channel their enthusiasm for the subject. For non students, if this stuff interests you,
then maybe think about joining a local astronomy club. Whole careers can be made
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