The model of our universe as expanding at an accelerated rate has given rise to theoretical constructs such as dark energy and dark matter, which scientists believe could make up 95% of the universe. In September, Horizon takes a deeper look at what we really know about the expanding universe. We speak to Prof. Subir Sarkar, who believes that the Nobel-winning discovery that universe expansion acceleration could be a fluke, and the scientists who are trying to answer the question by allowing us to better measure the expansion rate. We also look at the significance of accurately measuring gravity in deep space, and what dark matter haloes can tell us about the existence of dark energy.
New efforts to figure out just how fast the universe has expanded since the Big Bang, a speed known as the Hubble constant, could upend current theories of physics, according to some scientists.
The most mysterious phenomenon in cosmology – dark energy – may not exist at all, according to Professor Subir Sarkar, head of the particle theory group at the University of Oxford in the UK.
When it comes to climate change, it is often said that what happens in the Arctic does not stay in the Arctic. This month, with the COP24 UN climate change conference taking place in Katowice, Poland, Horizon looks north to the region of the world that is feeling the effects of global warming most acutely. We speak to Marianne Kroglund from the Arctic Council about whether it is too late to save the fragile ecosystems there and examine how studies of ice melt show that the world may still have a fighting chance of limiting sea level rise. We find out how the Arctic environment could be protected in the face of increased maritime traffic and look at the effect of melting permafrost – soil, sediment or rock that’s been frozen for at least two years – on the environment and local communities.
In its landmark report in October, the UN's International Panel on Climate Change said that every package of measures we choose to limit global temperature rises to 1.5°C must include a way of removing carbon dioxide emissions from the air and reusing or storing them. This month, Horizon looks at what's being done to advance these carbon capture, storage and utilisation technologies. We talk to one expert who is trying to trap emissions from the cement industry before they are released, and find out how International Space Station technology is inspiring the capture of ambient carbon dioxide. We also investigate how captured CO2 can be reused, and examine just how safe it is to store the gas underground.
As Earth's magnetic shield fails, so do its satellites. First, our communications satellites in the highest orbits go down. Next, astronauts in low-Earth orbit can no longer phone home. And finally, cosmic rays start to bombard every human on Earth.
Regular naps may be one of the privileges of retirement but research is pointing to napping as a contributor to cognitive decline. Scientists are now testing the idea that older people should instead meditate or learn a language to preserve brainpower and wellbeing.
A weakened magnetic field in the southern Atlantic Ocean gives us a glimpse of the future.
Meditation and language-learning being trialled to keep brains sharp.
With environmental changes locked in for several decades, are we too late to save the Arctic?