Why are scientists interested?
Famous astronomers, such as Cassini the first (1625-1712), Abbott Jean Picard (1620-1682), Jean Richer (1630-1696) and even Sir Edmond Halley (1656-1742) and later Joseph-Nicolas Delisle (1688-1768) refined the trigonometric method, called parallax.
However, the first measures of parallax, made using transits, were marred by an error due to an optical effect called the 'Black Drop effect'.
Since the Sixties, distance measurements using radar, as well as space probes, have allowed us to determine the size of our solar system far more accurately. This is when scientists came up with a new idea: Why not use the transit of Venus as a reference in the study of exoplanets?
There are many methods to detect exoplanets, which we will come back to later. One of these is called the "transit method". This method requires the observation of a possible transit. If a transit occurs, the apparent luminosity of the star reduces slightly (because a tiny fraction of its emitting surface is temporarily hidden). This method gives information on the mass, size and orbit of the planet.
Studying this transit will allow scientists to see if such measurements would allow them to answer fundament