Prachi Dave

DAY ONE

Upon my arrival, I was greeted by Tamara who also introduced me to my three other “colleagues” for the rest of the week. We then had a tour of the ICRAR building and got to know each other. We also met Greg, who we had been conversing with through email prior to the work experience. We then got down to place that was going to be our temporary home and met Matthew Young who was going to be our supervisor/teacher.

To start off, Matthew gave us a question to work on. It was difficult but by working together and with Matthew’s help, we found the equation for angular acceleration and velocity.
We then recorded how far away each planet is from the sun and how long they take to travel around the sun. Surprisingly, this was much harder than anything else as all of us kept getting wrong values. But in the end, we got it right and calculated the orbital speed and acceleration for each planet. We also graphed this information, but to get a gradient, we plotted log-log plots.

We then repeated this process for the Jupiter system – for its four moons: Io, Europa, Ganymede and Callisto, and also the Earth system with our very own moon.

Later, we went to have lunch and ended up getting lost, trying to find the shops. But in the end, we found our way back.
Using the previous information, we estimated the Sun’s and the Earth’s mass and we then derived Newton’s Law of Gravitation which is F = GMm/r^2.

And to end the day, we all took a walk around the UWA Campus, discussing things. We explored topics such as electrodynamics and the basics of quantum mechanics, but as we discussed such a broad area, we debated on what to call it when writing our blogs. We concluded to name it ‘physics’, very loosely.

DAY TWO

We started off the day with rediscussing ‘physics’ and the neutral hydrogen atom. The hydrogen atom has one proton and one electron which orbits the proton. We learned that as the electron spins, it begins to lose energy.

Using this information and equations such as Coulomb’s Law, Einstein-Planck equation, E = mc^2, F = ma and Orbital Mechanics equation (formulas from yesterday), we derived equations for the radius and velocity of an electron in its corresponding orbital in a hydrogen atom.

We put these equations into an excel spreadsheet to actually calculate the radius and velocity for the electron in each orbit, such as n=1 etc. Then we proceeded to calculate the kinetic energy, potential energy, change in total energy, frequency, and wavelength of the electron in the orbit.

And then we graphed a radius vs. velocity graph to get a rotation curve, then we also plotted a log-log graph to get its gradient.
Then we had lunch and after lunch, we finally connected to the UWA Small Radio Telescope (SRT), located in Gin Gin. Matthew taught us how to use the program and how to read the information that the telescope collects.

We messed around and had the telescope observing certain points in the galaxy. It records the radio transmission of the galaxy and plots a degree vs. velocity graph. Using the information from the graphs, we plotted a rough rotation curve for the Milky Way.

We discovered that the further you get away from the Galactic Centre of the galaxy, your velocity remains the same. It was not what we expected: that the further you get away, you should slow down – not remain at a constant speed. This allowed us to conclude that Newton’s equations were incorrect, or that some other mass exists in the world. The other matter is named Dark Matter; however, we have no data on it so we cannot prove it.

DAY THREE

On the third day, we again began to record information from the SRT, to try and get a more accurate graph. Unfortunately, the Radio Frequency Interference (RFI) was incredibly high, and we ended up getting worse data.
Later, Matthew turned up and showed us how to code to get the SRT recording data to get more accuracy and so that it can do it without us having to monitor it continuously.

After learning this and putting the code in so that it could start recording, we began our one-hour journey to Gin Gin to see the SRT in person.

We got there and had lunch first off and went off to explore the place.

At the end, we finally saw the SRT and where we connected to every time, we wanted to see the data.
Overall, it was a great day and we had lots of fun.

DAY FOUR

Today, we had another excursion planned – we were off to see the supercomputer at Pawsey Centre.

When we got there, we had a tour of the place and saw Perth’s largest supercomputer – Magnus. We then got to take apart two \$50 000 computer components as they had been decommissioned.

After this, we got to see Magnus Mini which was some sort of physics simulation tester. We got to test this and were given the challenge of trying to get the least number of Frames Per Second (FPS). The Uni students in charge of it had gotten down to 28 FPS and that took them ages to do. Us, however, got down to 10 FPS within half-an-hour.

Then we had two Zoom conferences with other Pawsey interns and learn about value-setting, resiliency and problem-solving. Again, this was another fantastic day.

DAY FIVE

On the last day, we were to analyse the recorded data from the SRT that we had collected on the Third Day. Unfortunately, the RFI had remained high for the entire day and we didn’t collect proper information. Fortunately, though, Matthew gave us data for one of the points that he had collected from the previous years.

However, it was really difficult to this.

It was only one point in the galaxy, but the data was massive! On excel, the data went up to FI horizontally and 2395 vertically.
We eventually sorted through the data (our fingers were so sore from scrolling!) and we graphed the frequency vs. intensity graphs for all that data.

Using the graph, we found the maximum frequency and its corresponding intensity. Using this information, we calculated the maximum velocity of the mass at that point, maximum velocity relative to the angle that the point makes with the galactic centre and finally, the radius between the point and galactic centre.

It took us all day to calculate this information for only one point, and we still had six or seven others to do. However, the work experience was at end. It was sad as I had made life-long friends and had such an amazing time, and that now I had to go back to my boring, mundane life.

In the end, this work experience was beyond my expectations and had to be the best week I’ve had in 2020. I learnt so much, met absolutely amazing people and become more confident that I want to pursue astrophysics as a career when I’m older.

To anyone else considering doing this ICRAR work experience, why are you even considering it? The answer should be obvious; yes! I highly, highly recommend it. It is absolutely amazing!

PRACHI DAVE