12 Jun 2017
The summer is almost here, and the stars look more fascinating every night, especially if you're away from the light pollution of the city
The summer is almost here, and the stars look more fascinating every night, especially if you're away from the light pollution of the city. Recognising the constellations is a fun way to orientate yourself among the stars, but they only take that form for us: seen from another point of the galaxy, they would look completely different.
Moreover, the stars that make up the constellations appear to be immobile, but that won't always be the case. Orion is one of the most famous, both for its easily recognisable form and its privileged position, making it easy to see from almost anywhere on our planet. However, its shape won't stay the same forever, because the stars are changing position - although their movements are too slow to be seen by the naked eye, or over a single lifetime. In order to understand them, we needed to use the high precision observations collected by missions such as Gaia and Hipparcos, by ESA.
By collecting the data from these two space missions and putting them together with observations from Earth, scientists have created a video that plays out how the stars will move in the next 450,000 years in around one minute. One of the brightest stars that we can see is the red supergiant Betelgeuse, and it can be seen in the first part of the video to the top centre of the frame, with its yellow-orange colour. Betegeuse's movement will take it out of sight in around 100,000 years.
o the bottom of the picture, on the other hand, you can see Rigel (to the left), the blue supergiant in the Orion constellation. To the bottom left is Aldebaran, a red giant that is part of Taurus, and which moves to the left during the video. The animation does not take account of the fact that over the period simulated, some visible stars will explode like supernovas and others will be born, such as in the Orion nebula, which is invisible to Gaia but is much brighter in infrared.