Why fusion promises clean unlimited energy and one firm hopes to spark it with high-speed collisions.
Read moreBy Ben Morris
Technology of Business editor

Facebook's global head of safety, Antigone Davis, testifies to the US Senate, about child protection.

Facebook's global head of safety, Antigone Davis, testifies to the US Senate, about child protection.
The forecasting system can predict the weather with about 89% accuracy.
Google tells an EU court the number-one search on its biggest rival is for Google.
Waze is using push notifications to ask for data on fuel supplies to notify others.
Videos saying vaccines cause autism, cancer or infertility are among those banned from the platform.
Astro can patrol the home when you're not there, or be remotely controlled.
Warehouse workers can no longer be sacked for time off task if they have good reason to take breaks.

Facebook's global head of safety, Antigone Davis, testifies to the US Senate, about child protection.
The forecasting system can predict the weather with about 89% accuracy.
Google tells an EU court the number-one search on its biggest rival is for Google.
Waze is using push notifications to ask for data on fuel supplies to notify others.
Videos saying vaccines cause autism, cancer or infertility are among those banned from the platform.
Astro can patrol the home when you're not there, or be remotely controlled.
Warehouse workers can no longer be sacked for time off task if they have good reason to take breaks.
The forecasting system can predict the weather with about 89% accuracy.
Google tells an EU court the number-one search on its biggest rival is for Google.
Waze is using push notifications to ask for data on fuel supplies to notify others.
By Ben Morris
Technology of Business editor
Senator Blumenthal asked a tech giant executive to end the company's Finsta product.
By Cristina Criddle
Technology reporter
By Manish Pandey
Newsbeat reporter
Dubai’s Lost Chambers Aquarium app tells users about conservation projects and endangered status.
By Michael Baggs
Newsbeat reporter

By Rory Cellan-Jones
Technology correspondent
Jack, Wesley and Darcy, who are all 14 and 15, set up CovidBaseAU anonymously to track data in Australia.
By Jane Wakefield
Technology reporter
By John Campbell
BBC News NI Economics & Business Editor
By Matthew Richards
BBC News