By Oscar Barragán
The night has finally arrived at the Roque de Los Muchachos Observatory. The blue sky has turned into a deep ocean full of stars which eclipses the beautiful horizon that is scattered with pink clouds. The telescopes are ready to hunt for starlight. At first sight, all the stars seem static in the night sky which is victim to the Earth’s rotation. However, this is a misconception, as all the stars that shine at night are moving within our galaxy, the Milky Way. Our mission for the night is is to detect their subtle movement which may tell us about the existence of faraway worlds.
Sunrise at the TNG in La Palma. Photo credit: Oscar Baragán.
The motion of the stars manifests itself in two ways. The first one is their movement in the plane of the sky – also known as their proper motion- which slowly re-shapes the constellations. The second one, and the one that we are searching for, is the movement of the stars with respect to us. This receding and approaching velocity of the stars is known as their radial velocity. This stellar motions, however, is so small that is is imperceptible to ...