What is art? What makes it good? And other things Signal festival makes you think about

The woman on stage is talking about space simulations, as in, creating minutely detailed reenactments of what it would like to take a crew into space. And if anyone would know about this sort of thing, it's this lady, astrobiologist Michaela Musilová. Variously described as an 'analogue astronaut' and a 'marsonaut' (i.e. a speculative explorer of Mars), Slovakia-born Musilová has worked with the likes of NASA and the European Space Agency (ESA), claiming the title of having led the most simulated missions to Mars and the Moon in history. To date, she's clocked up more than 30 'trips' to these extraterrestrial landscapes.

No one could deny that hearing about her intense simulated missions—every detail recreated in a minute, stifling, claustrophobic detail—is fascinating. You can't help but be captivated by the oddness of the photos documenting Musilová and her peers cooped up in tiny, flightless spaceships.

However, it isn't necessarily what you'd expect – a totally space-centric talk as the keynote at Signal Forum, the conference arm of the Prague-based festival of digital art. Sure, creating simulations of Mars missions inherently involves creativity – but it's certainly not 'art', or even design, as we usually understand it.

Many people would argue that science itself is an art form – and there's no doubt that there's beauty to be found everywhere within its many fields, not to mention the ways in which nature, mathematics, artistic principles, physicals, et al. are inextricably linked. Scientific and mathematical concepts of 'sacred geometry' underpin so much in both nature and art: take the way certain seashells correspond to the Fibonacci sequence, for instance, or the 'golden ratio' logarithmic spiral plays out in not just mathematics, but flower petals and the principles of image composition. To deny the links between art and science is to deny Leonardo da Vinci and the entire Renaissance.

But if science is an art form, or indeed art is science, why did the former government decimate the arts curriculum and relentlessly champion STEM subjects? There's a clear delineation between the two worlds when it comes to not only the way education is timetabled and funded – it permeates culture more broadly in the way we causally ascribe people as 'arty types' vs' science types', creatives, tech-bros; we talk about brains being 'maths' or 'words', Sudoku vs Wordle. One of the best things about Signal is that it doesn't make these sorts of arbitrary distinctions between art and science – it actively unites them.

Now in its 12th year, Signal Festival combines contemporary visual art, urban space, and modern technology through a series of artworks dotted around the city—22 installations for the 2024 edition. These are broadly situated in three main clusters: the Gallery Zone, Prague's city centre, and, for the first time, the stunning area around Prague Castle.

The lethal combination of my total lack of sense of direction and inability to read both maps and Czech meant I didn't get to see every single artwork at the festival. There was a lot of misguided meandering back and forth over the river, but despite all that, there was a real sense of magic to the whole thing. The nighttime aspect definitely helps: running from 7pm until midnight, the 'after-hours art' thing has a different resonance to a bright daylight arts event. A night out becomes a gallery visit, and vice versa.

The pieces that were in public spaces felt particularly joyful: there was something faintly surreal about mooching around Prague Castle, battling through hordes of tourists and tour guides holding up flags, and weekenders drinking their first glühwein of the season. Having barely spent an hour in the city, I left Jiří Příhoda 's superb show at Sternberg Palace, turned the corner and had absolutely no idea that the first thing I'd see (and hear) was the Archbishop's Palace illuminated by the Filip Hodas 'video mapping artwork, and soundtracked by booming techno-leaning beats.

The monumental Archbishop's Palace is thoroughly grandiose, with its Baroque architecture and rococo façade almost entirely unchanged since the 17th century. Hodas' Eternal Recurrence brings that architecture to life in bombastic new ways, using layered video mapping to both highlight certain design elements of the building and "tell a digital saga about the origin and evolution of life forms," according to Signal Festival. While that theme didn't entirely come across, it looked and sounded absolutely stunning.

In the days after the festival, reflecting on the works that really stood out and those that felt somewhat less memorable, a distinct pattern emerged, for which Hodas' piece could have been the blueprint. The main thing that defined the memorable camp was how the artworks responded to their space: they were so fundamentally rooted in their specific locality that they really couldn't have worked anywhere else. Meanwhile, those that didn't feel quite so arresting were largely those that could have been placed anywhere – indoors or outdoors, in a gallery or churchyard, Prague, Paris or Peterborough.

That rigorous site-specificity is central to the approach of renowned Czech artist Jiri Prihoda (read our interview here); and plays out beautifully in Capriccio, which spans the Sternberg Palace's stables hall. It takes its name from the Capriccio painting style, which originated during the Renaissance. It is a type of landscape painting based on fantastical combinations of architectural elements and buildings. Prihoda's piece draws heavily on the concept of perspective – another Renaissance invention – forcing you to gaze down the long, vast space, guided by a comet-like light that zooms across the ceiling above your head. The word 'immersive' has been bandied about so much that it often becomes meaningless, but Capriccio really is: you have to enter into the tunnel-like artwork in order to move through the building, making for a brilliantly confrontational intervention, but one that feels totally calm and meditative.

Prihoda's Capriccio, like Hodas' video mapping, simply couldn't exist elsewhere: it delights in the possibilities of the space and constantly riffs on the ideas that are central to it. As well as those Renaissance references, the work is constructed on the precise foundations of Cartesian geometry, the mathematical premise that marries the proportional canons of classical architecture and the laws of physics. It plays with the hall's unique interplay of light and shadow; it forces you to look not just ahead, around, and behind but up – you can't avoid taking in that breathtaking ceiling.

Similarly, Laterna Magika's piece, Iron Horse: Fractured, used choreography, live-action theatrics and video projection to reconfigure the courtyard of the Clam-Gallas Palace. It was a very different proposition to pretty much everything else I saw at Signal, using both modern technology and traditional actors/dancers. Directed by Miřenka Čechová, the multidisciplinary performance piece combined theatre, dance, and audiovisual art to make us viewers into voyeurs, peering into the windows of passing trains, with fragmented scenes suggesting everything from romance to murder, with a hefty dose of Hitchcockian symbolism.

As one of the Prague National Theatre's ensembles, Laterna Magika began life almost 70 years ago at Expo 58 in Brussels, where it was founded as the cultural representative for the then-Czechoslovak Socialist Republic. From the outset, under the directorship of Alfréd Radok and Josef Svoboda, it combined film projection and live stage performance (a pretty radical approach in 1958. The pair set out a clear definition of Laterna Magika's principles regarding the relationship between on-stage action and projected film: "Projection is not only a mobile backdrop, nor does it only create an appearance of reality; the key factor is the interconnection between the content of what is happening on stage and the action on the film screen."

That idea of interconnection feels pertinent. It's the thread that neatly brings together the standout works and themes of Signal 2024: the interconnection of the artworks and their sites; of the city, the installations, and their viewers; the connections forged between historical architecture and reference points with cutting-edge technologies. And to return to where we started, the interconnection of art and science – a link so inherent to all that Signal celebrates that it barely needs to celebrate it at all.