Alone in space or not. We shall soon know the answer! – Niels Bohr Institute - University of Copenhagen

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06 December 2018

Alone in space or not. We shall soon know the answer!

Inaugural lecture

Research of recent years has shown that there are plenty of planets around other stars in the Milkyway that could potentially be inhabited. 10 billion at least. So it is reasonable to assume that life has made foothold on at least some of them. But so far well documented visits from aliens have been rather sparse – so this could be an indication of the fact that there aren’t any cultures developed enough to be able to come calling. If this is really the case, why is it so? What makes our solar system so unique that the probability of life on no less than 10 billion planets is actually not that high? Professor in Astrophysics and Planetary research, Uffe Graae Jørgensen, the Niels Bohr Institute, University of Copenhagen, gives his inaugural talk, and tells us about why we are only a few years from knowing the answer to one of the greatest questions of mankind.

Photo: Ola Joensen

The Earth is not special. But Saturn and Jupiter are

When we look at the other solar systems in the Milkyway, what’s special about them is not that they have an Earth size planet orbiting the star in the distance we call the habitable zone – that is, the distance that allows for the existence of fluent water. Almost all of them have that. Only a few of the other solar systems have large gas planets like Jupiter and Saturn, and if they do, they are almost exclusively in orbits closer to their star. In our solar system, the orbits of Jupiter and Saturn 3.9 billion years ago caused a bombardment of the Earth with material, perhaps containing water and other basic elements necessary for the forming of life. So possibly, Jupiter and Saturn have played a crucial role for the forming of life on Earth.

Lack of atmospheric equilibrium is a sign of life

Life on a planet creates an imbalance in the atmosphere. The living organisms produce oxygen through the photosynthesis of plants and methane from other living organisms. So you don’t have to go looking for UFO runways or other structures made by intelligent beings, if you want to find evidence of biological activity. All you have to do is measure the content of different gasses in the atmosphere. If there is no biological activity, the atmosphere is in equilibrium – nothing is added to it and we have very good examples of that in our neighbourhood: Venus and Mars. Their atmospheres contain almost exclusively CO2.

Collaboration between scientists and observations from a gigantic telescope provide the answer

A series of different branches of research are combined at the Niels Bohr Institute in order to provide the best foundation for interpretation of the data we shall soon have from a giant telescope. It is the common European ELT telescope, which is currently under construction in the Chilean Atacama desert. It will command a mirror of 40 meters and a focal length of half a kilometer, which will enable it to distinguish the picture of an Earth-size planet in an Earth-like orbit around a Sun-like star. A series of satellites will be adding observations to the ones of the telescope. Spectra, i.e. measurements of the distribution of gasses in the atmosphere, will be provided by ELT and all of this data combined will be an important part of the material the researchers will be working with. Collaboration between many scientists from different fields will be analyzing and interpreting the observations. The best climate models, the best star atmosphere models and the theoretical research from researchers in biocomplexity are combined at the Niels Bohr Institute to form a foundation for interpreting and contextualizing the observations correctly.

Professor Uffe Graae Jørgensen will be giving his inaugural lecture at

GM Auditorium, Geologisk Museum
Øster Voldgade 5-7
1350 København K
Thursday 13th December, 2pm – 4pm.
The lecture will be given in English