The heaviest thing in the Galaxy has now been imaged by the biggest telescope on Earth. This is Sagittarius A*, the supermassive black hole at the centre of our Galaxy – a gas and star-consuming object, a 4 million times the mass of the Sun. The Event Horizon Telescope is not one device but a consortium of radio telescopes ranging from the South Pole to the Arctic Circle. Their combined data allowed astronomers to focus in on this extreme object for the first time. Astronomer Ziri Younsi from University College London talks to Roland Pease about the orange doughnut image causing all the excitement.

Also in the programme…

Climatologist Chris Funk talks about the role of La Niña and climate change in the record-breaking two year drought that continues to threaten the lives and livelihoods of millions of people in East Africa.

Was a pig virus to blame for the death of the first patient to receive a pig heart transplant? We talk to the surgeon and scientist at the University of Maryland School of Medicine who led the historic animal to human transplant operation this year.

How easy will it be to grow plants in lunar soil on future moon bases? Plant biologist Anna Lisa Paul has been testing the question in her lab at the University of Florida, Gainesville, with cress seeds and lunar regolith collected by the Apollo missions.

And….

Does photographic memory exist?

Most people are great at remembering key points from important events in their lives, while the finer details - such as the colour of the table cloth in your favourite restaurant or the song playing on the radio while you brushed your teeth - are forgotten.

But some people seem to have the power to remember events, documents or landscapes with almost perfect recall, which is widely referred to as having a photographic memory. CrowdScience listeners Tracy and Michael want to know if photographic memory actually exists and if not, what are the memory processes that allow people to remember certain details so much better than others?

Putting her own memory skills to the test along the way, presenter Marnie Chesterton sets out to investigate just what’s happening inside our brains when we use our memories, the importance of being able to forget and why some people have better memories than others.

Photo: First image of Sgr A*, the supermassive black hole at the centre of our galaxy Credit: EHT Collaboration, Southern European Observatory

Presenter: Roland Pease and Marnie Chesterton Producer: Andrew Luck-Baker and Hannah Fisher