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.
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.
Dumped waste, from used nappies to industrial by-products, have long wound up in landfills and can take hundreds of years to decay. In October we speak to the scientists figuring out how to keep such items in use to reduce rubbish and create a so-called circular economy. We learn about new efforts to mine industrial waste for the rare metals that go into making aircraft parts, pacemakers and bicycle gears, and find out about the culture shift needed to develop a zero-waste society. We also speak to the researchers building a biorefinery to turn soiled nappies into fertilisers and raw materials, and look at whether seaweed could become the next plastic.
A new type of use-by label for milk bottles that decomposes as the liquid inside goes sour could appear on UK supermarket shelves later this year. Labels such as these, capable of telling consumers exactly when fresh produce has gone bad, are being developed by scientists who want to stop food from being prematurely discarded. If successful, these indicators have the potential to reduce the millions of tonnes of valuable food thrown away each year.
When astronauts aboard the International Space Station (ISS) exhale carbon dioxide (CO2), it’s removed from the air and pumped into space. Could an Earth-based version help remove greenhouse gas emissions from our atmosphere?
Wireless tags and indicators that mimic decomposition could replace expiry dates.
Capturing carbon dioxide from air is a vital part of limiting global warming.
Deploying this technology rests on successfully making a business case to companies, says Kristin Jordal.