Just ask! That's what our viewer Nazar Omer Hassan Salih in Sudan wants to know.

This week's viewer question comes from Brown Mbadiwe in Owerri, Nigeria.

Indonesia's Citarum River is one of the most polluted waterways in the world. But by 2025, it should have potable water - according to a government plan. A military-led initiative is helping to collect plastic waste in the river with the help of a floating barrier.

It isn't only physicists who are fascinated by light. Poets too have been entranced by its powers. Photons have mysterious properties. Perhaps this is why we like to light candles when we're feeling contemplative.

In Morocco, researchers are helping local farmers protect insect populations and boost their yields. The project called Farming with Alternative Pollinators encourages farmers to grow a variety of insect-attracting plants alongside their main crop.

Brazil still has hundreds of open landfill sites full of garbage. Now a university in the capital Brasília is helping to implement a new, sustainable waste management system. The program aims to increase the proportion of waste that is recycled.

The rise in antibiotic-resistant bacteria is an urgent medical problem. At Germany's Helmholtz Center for Infection Research, a researcher from Indonesia is hoping to find potent antimicrobial substances in soil samples from mangrove swamps.

This week's viewer question was sent in by Arnulfo Quintanilla from El Salvador.

Scientists will soon be able to predict solar storms with a special orbiter, launched on 10 February. Its job is to track the visible surface of the sun and at the same time map its magnetic field, thereby providing glimpses into the inner life of the sun.

The Tomorrow Today viewer question this week comes from Salvador Salazar in Venezuela.