On October 31, Dark Matter Day was celebrated worldwide. On this occasion, Tartu Observatory and Old Observatory of University of Tartu created a special program where science and art come together to shed light on the universe’s greatest mystery – dark matter.
Dark matter is the Universe’s invisible superstar! Even though we can’t see it, we know that dark matter is all around us and makes up a whole quarter of the Universe’s mass and energy. And that’s not all — the Universe’s expansion is driven by a mysterious force called dark energy, which takes up as much as 70 percent of the Universe. This means that a large part of the Universe is still a big mystery waiting to be solved!
Studies of dark matter are closely linked to Estonia and Tõravere. Read the article “Five decades of missing matter”.
From October 29 to November 5, Dark Matter Week was celebrated with public lectures aimed at exploring the cosmic mysteries and an art exhibition.
On 29 October 2024, one of our Management Committee member, Manuel Hohmann, an Associate Professor of Theoretical Physics at University of Tartu, discussed three stories about the mysteries, questions, and possible answers regarding the dark universe.
Abstract: Astronomical observations show that visible matter, which includes stars, planets, and us, makes up only 5% of the universe’s matter content. About 25% is dark matter: an unknown source of gravity that neither emits nor absorbs light, and which we can only detect through its effects on the movement of visible matter.
Even more challenging is the detection of dark energy, which makes up the remaining 70% of the universe, and whose only observable effect is the accelerating expansion of the universe. Observations clearly indicate the amounts of these dark universe components and the properties they must have, but they do not answer the question of what the dark universe is made of: are they unknown heavy particles, black holes, vacuum energy, or something else? This is perhaps the most famous mystery of modern physics. Since the dark universe has so far only manifested itself through gravity, the question arises whether our understanding of gravity is correct.
The video of his talk can be seen (in Estonian) here.
Science philosopher Enn Kasak also discussed in his lecture how the deeper inclusion of quantum theory in describing the universe compels us to rethink concepts such as reality, spacetime, and matter — both in its “dark” and “light” forms.
The video of his talk can be seen (in Estonian) here.