Using a MakeBlock educational, programmable robot (mBot) along with some common household items, create a model that demonstrates the Transit Method — one of the most successful methods used to detect and study planets orbiting other stars.
In the last 25 years over 3,500 planets have been discovered orbiting stars other than our Sun. We call these ‘exo-planets’. One of the most successful methods for detecting exo-planets is called the Transit Method.
The transit method is very similar to Solar eclipses. From Earth we look at a planet circling a distant star. As the planet moves around its star there is a point where it is between the Earth and the star, blocking out a little bit of the light. By measuring the dip in the brightness of the star and the length of time it takes, astronomers can learn about the planet passing in front of the star.
Members of the Las Cumbres Observatory science team, in partnership with an international group of astronomers, are using LCO to study exoplanets using Transit Method, amongst others. Using Transit Method astronomers can get valuable information about the planet's orbital path, size, atmosphere and surface temperatures.
More information about transit method can be found on LCO’s Spacebook: https://lco.global/spacebook/transit-method/
Follow these instructions to build a simple model that will demonstrate transit method. The model allows you to measure the amount of light collected by a light sensor and explore how the number changes when an object moves between the light source and sensor; simulating an exoplanet passing between us and its star.
Using this model you may experiment with different planet sizes, orbital lengths and orbital speeds, to see how these factors affect your measurements.
To programme the mBot you will need to install the mBlock programme on your computer: http://www.mblock.cc
Programming this model is easy, you can either download the pre-made SB2 file (mbot-transit.sb2) which can be opened in the mBlock programme and immediately uploaded to your mBot core using the USB cable, or create your own code in the mBlock programme.
Minimal requirements for your model:
Optional: add an extra dimension by programming the speaker onboard the mCore to beep each time the ambient light drops.
To upload your code you must connect your model to your computer using the USB cable. Ensure your model is switched and and connect the USB cable in mBlock by clicking Connect > Serial Port and selecting /dev/tty.wchusbserial142.
Next, right-click on your starter block (e.g. the mBot Programme block) and select upload to Arduino
When you have finished building your model, and the code is uploaded, you should have a simple simulation of an exoplanetary system that can be used to demonstrate transit method. As the motor rotates, your exoplanet orbits. Once during each orbit it will pass between the light sensor and the LED, blocking some of the light. The LED screen displays the amount of light measured by the light sensor onboard the mCore, the value should visibly drop each time the exoplanet passes between the light and the sensor.
Your model allows you to alter the colour of your star, the size of the planet, the length of the planetary orbit and the orbital speed. Explore how these factors affect the amount of light detected?